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| author | Matěj Cepl <mcepl@cepl.eu> | 2023-01-11 09:37:51 +0100 |
|---|---|---|
| committer | Matěj Cepl <mcepl@cepl.eu> | 2023-01-11 09:37:51 +0100 |
| commit | ad3932128a6b98d93f4a64c0bac67112b89c33e2 (patch) | |
| tree | e40839c5b587aea240bc3d42b757777678aeb62b /rfcs/RFC 4918 - HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV).html | |
| parent | bed92eae10558cdd8eddfd91f5d8addaf509413c (diff) | |
| download | jsCalDAV-ad3932128a6b98d93f4a64c0bac67112b89c33e2.tar.gz | |
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diff --git a/rfcs/RFC 4918 - HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV).html b/rfcs/RFC 4918 - HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV).html new file mode 100644 index 0000000..748cdbf --- /dev/null +++ b/rfcs/RFC 4918 - HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV).html @@ -0,0 +1,7186 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head profile="http://dublincore.org/documents/2008/08/04/dc-html/"> +<meta http-equiv="content-type" content="text/html; charset=UTF-8"> + <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> + <meta name="robots" content="index,follow"> + <meta name="creator" content="rfcmarkup version 1.109"> + <link rel="schema.DC" href="http://purl.org/dc/elements/1.1/"> +<meta name="DC.Relation.Replaces" content="rfc2518"> +<meta name="DC.Identifier" content="urn:ietf:rfc:4918"> +<meta name="DC.Date.Issued" content="June, 2007"> +<meta name="DC.Creator" content="Lisa Dusseault <ldusseault@commerce.net>"> +<meta name="DC.Description.Abstract" content="Web Distributed Authoring and Versioning (WebDAV) consists of a set of +methods, headers, and content-types ancillary to HTTP/1.1 for the +management of resource properties, creation and management of resource +collections, URL namespace manipulation, and resource locking +(collision avoidance). RFC 2518 was published in February 1999, and +this specification obsoletes RFC 2518 with minor revisions mostly due +to interoperability experience. [STANDARDS-TRACK]"> +<meta name="DC.Title" content="HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)"> + + <link rel="icon" href="index_files/rfc.png" type="image/png"> + <link rel="shortcut icon" href="index_files/rfc.png" type="image/png"> + <title>RFC 4918 - HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)</title> + + + <style type="text/css"><!--
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+--></script> +</head> +<body onload=""> + <div style="height: 13px;"> + <div onmouseover="" onclick="" onmouseout="" style="height: 6px; position: absolute;" class="pre noprint docinfo bgblue" title="Click for colour legend."> </div> + <div id="legend" class="docinfo noprint pre legend" style="position:absolute; top: 4px; left: 4ex; visibility:hidden; background-color: white; padding: 4px 9px 5px 7px; border: solid #345 1px; " onmouseover="" onmouseout=""> + </div> + </div> +<span class="pre noprint docinfo top">[<a href="http://tools.ietf.org/html/" title="Document search and retrieval page">Docs</a>] [<a href="http://tools.ietf.org/rfc/rfc4918.txt" title="Plaintext version of this document">txt</a>|<a href="http://tools.ietf.org/pdf/rfc4918" title="PDF version of this document">pdf</a>] [<a href="http://tools.ietf.org/html/draft-ietf-webdav-rfc2518bis" title="draft-ietf-webdav-rfc2518bis">draft-ietf-webdav...</a>] [<a href="http://tools.ietf.org/rfcdiff?difftype=--hwdiff&url2=rfc4918" title="Inline diff (wdiff)">Diff1</a>] [<a href="http://tools.ietf.org/rfcdiff?url2=rfc4918" title="Side-by-side diff">Diff2</a>] [<a href="https://www.rfc-editor.org/errata_search.php?rfc=4918">Errata</a>] </span><br> +<span class="pre noprint docinfo"> </span><br> +<span class="pre noprint docinfo">Updated by: <a href="http://tools.ietf.org/html/rfc5689">5689</a> PROPOSED STANDARD</span><br> +<span class="pre noprint docinfo"> <span style="color: #C00;">Errata Exist</span></span><br> +<pre>Network Working Group L. Dusseault, Ed. +Request for Comments: 4918 CommerceNet +Obsoletes: <a href="http://tools.ietf.org/html/rfc2518">2518</a> June 2007 +Category: Standards Track + + + <span class="h1"><h1>HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)</h1></span> + +Status of This Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (C) The IETF Trust (2007). + +Abstract + + Web Distributed Authoring and Versioning (WebDAV) consists of a set + of methods, headers, and content-types ancillary to HTTP/1.1 for the + management of resource properties, creation and management of + resource collections, URL namespace manipulation, and resource + locking (collision avoidance). + + <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a> was published in February 1999, and this specification + obsoletes <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a> with minor revisions mostly due to + interoperability experience. + + + + + + + + + + + + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 1]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-2" id="page-2" href="#page-2" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +Table of Contents + + <a href="#section-1">1</a>. Introduction ....................................................<a href="#page-7">7</a> + <a href="#section-2">2</a>. Notational Conventions ..........................................<a href="#page-8">8</a> + <a href="#section-3">3</a>. Terminology .....................................................<a href="#page-8">8</a> + <a href="#section-4">4</a>. Data Model for Resource Properties .............................<a href="#page-10">10</a> + <a href="#section-4.1">4.1</a>. The Resource Property Model ...............................<a href="#page-10">10</a> + <a href="#section-4.2">4.2</a>. Properties and HTTP Headers ...............................<a href="#page-10">10</a> + <a href="#section-4.3">4.3</a>. Property Values ...........................................<a href="#page-10">10</a> + <a href="#section-4.3.1">4.3.1</a>. Example - Property with Mixed Content ..............<a href="#page-12">12</a> + <a href="#section-4.4">4.4</a>. Property Names ............................................<a href="#page-14">14</a> + <a href="#section-4.5">4.5</a>. Source Resources and Output Resources .....................<a href="#page-14">14</a> + <a href="#section-5">5</a>. Collections of Web Resources ...................................<a href="#page-14">14</a> + <a href="#section-5.1">5.1</a>. HTTP URL Namespace Model ..................................<a href="#page-15">15</a> + <a href="#section-5.2">5.2</a>. Collection Resources ......................................<a href="#page-15">15</a> + <a href="#section-6">6</a>. Locking ........................................................<a href="#page-17">17</a> + <a href="#section-6.1">6.1</a>. Lock Model ................................................<a href="#page-18">18</a> + <a href="#section-6.2">6.2</a>. Exclusive vs. Shared Locks ................................<a href="#page-19">19</a> + <a href="#section-6.3">6.3</a>. Required Support ..........................................<a href="#page-20">20</a> + <a href="#section-6.4">6.4</a>. Lock Creator and Privileges ...............................<a href="#page-20">20</a> + <a href="#section-6.5">6.5</a>. Lock Tokens ...............................................<a href="#page-21">21</a> + <a href="#section-6.6">6.6</a>. Lock Timeout ..............................................<a href="#page-21">21</a> + <a href="#section-6.7">6.7</a>. Lock Capability Discovery .................................<a href="#page-22">22</a> + <a href="#section-6.8">6.8</a>. Active Lock Discovery .....................................<a href="#page-22">22</a> + <a href="#section-7">7</a>. Write Lock .....................................................<a href="#page-23">23</a> + <a href="#section-7.1">7.1</a>. Write Locks and Properties ................................<a href="#page-24">24</a> + <a href="#section-7.2">7.2</a>. Avoiding Lost Updates .....................................<a href="#page-24">24</a> + <a href="#section-7.3">7.3</a>. Write Locks and Unmapped URLs .............................<a href="#page-25">25</a> + <a href="#section-7.4">7.4</a>. Write Locks and Collections ...............................<a href="#page-26">26</a> + <a href="#section-7.5">7.5</a>. Write Locks and the If Request Header .....................<a href="#page-28">28</a> + <a href="#section-7.5.1">7.5.1</a>. Example - Write Lock and COPY ......................<a href="#page-28">28</a> + 7.5.2. Example - Deleting a Member of a Locked + Collection .........................................<a href="#page-29">29</a> + <a href="#section-7.6">7.6</a>. Write Locks and COPY/MOVE .................................<a href="#page-30">30</a> + <a href="#section-7.7">7.7</a>. Refreshing Write Locks ....................................<a href="#page-30">30</a> + <a href="#section-8">8</a>. General Request and Response Handling ..........................<a href="#page-31">31</a> + <a href="#section-8.1">8.1</a>. Precedence in Error Handling ..............................<a href="#page-31">31</a> + <a href="#section-8.2">8.2</a>. Use of XML ................................................<a href="#page-31">31</a> + <a href="#section-8.3">8.3</a>. URL Handling ..............................................<a href="#page-32">32</a> + <a href="#section-8.3.1">8.3.1</a>. Example - Correct URL Handling .....................<a href="#page-32">32</a> + <a href="#section-8.4">8.4</a>. Required Bodies in Requests ...............................<a href="#page-33">33</a> + <a href="#section-8.5">8.5</a>. HTTP Headers for Use in WebDAV ............................<a href="#page-33">33</a> + <a href="#section-8.6">8.6</a>. ETag ......................................................<a href="#page-33">33</a> + <a href="#section-8.7">8.7</a>. Including Error Response Bodies ...........................<a href="#page-34">34</a> + <a href="#section-8.8">8.8</a>. Impact of Namespace Operations on Cache Validators ........<a href="#page-34">34</a> + <a href="#section-9">9</a>. HTTP Methods for Distributed Authoring .........................<a href="#page-35">35</a> + <a href="#section-9.1">9.1</a>. PROPFIND Method ...........................................<a href="#page-35">35</a> + <a href="#section-9.1.1">9.1.1</a>. PROPFIND Status Codes ..............................<a href="#page-37">37</a> + + + +<span class="grey">Dusseault Standards Track [Page 2]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-3" id="page-3" href="#page-3" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + <a href="#section-9.1.2">9.1.2</a>. Status Codes for Use in 'propstat' Element .........<a href="#page-37">37</a> + <a href="#section-9.1.3">9.1.3</a>. Example - Retrieving Named Properties ..............<a href="#page-38">38</a> + 9.1.4. Example - Using 'propname' to Retrieve All + Property Names .....................................<a href="#page-39">39</a> + <a href="#section-9.1.5">9.1.5</a>. Example - Using So-called 'allprop' ................<a href="#page-41">41</a> + <a href="#section-9.1.6">9.1.6</a>. Example - Using 'allprop' with 'include' ...........<a href="#page-43">43</a> + <a href="#section-9.2">9.2</a>. PROPPATCH Method ..........................................<a href="#page-44">44</a> + <a href="#section-9.2.1">9.2.1</a>. Status Codes for Use in 'propstat' Element .........<a href="#page-44">44</a> + <a href="#section-9.2.2">9.2.2</a>. Example - PROPPATCH ................................<a href="#page-45">45</a> + <a href="#section-9.3">9.3</a>. MKCOL Method ..............................................<a href="#page-46">46</a> + <a href="#section-9.3.1">9.3.1</a>. MKCOL Status Codes .................................<a href="#page-47">47</a> + <a href="#section-9.3.2">9.3.2</a>. Example - MKCOL ....................................<a href="#page-47">47</a> + <a href="#section-9.4">9.4</a>. GET, HEAD for Collections .................................<a href="#page-48">48</a> + <a href="#section-9.5">9.5</a>. POST for Collections ......................................<a href="#page-48">48</a> + <a href="#section-9.6">9.6</a>. DELETE Requirements .......................................<a href="#page-48">48</a> + <a href="#section-9.6.1">9.6.1</a>. DELETE for Collections .............................<a href="#page-49">49</a> + <a href="#section-9.6.2">9.6.2</a>. Example - DELETE ...................................<a href="#page-49">49</a> + <a href="#section-9.7">9.7</a>. PUT Requirements ..........................................<a href="#page-50">50</a> + <a href="#section-9.7.1">9.7.1</a>. PUT for Non-Collection Resources ...................<a href="#page-50">50</a> + <a href="#section-9.7.2">9.7.2</a>. PUT for Collections ................................<a href="#page-51">51</a> + <a href="#section-9.8">9.8</a>. COPY Method ...............................................<a href="#page-51">51</a> + <a href="#section-9.8.1">9.8.1</a>. COPY for Non-collection Resources ..................<a href="#page-51">51</a> + <a href="#section-9.8.2">9.8.2</a>. COPY for Properties ................................<a href="#page-52">52</a> + <a href="#section-9.8.3">9.8.3</a>. COPY for Collections ...............................<a href="#page-52">52</a> + <a href="#section-9.8.4">9.8.4</a>. COPY and Overwriting Destination Resources .........<a href="#page-53">53</a> + <a href="#section-9.8.5">9.8.5</a>. Status Codes .......................................<a href="#page-54">54</a> + <a href="#section-9.8.6">9.8.6</a>. Example - COPY with Overwrite ......................<a href="#page-55">55</a> + <a href="#section-9.8.7">9.8.7</a>. Example - COPY with No Overwrite ...................<a href="#page-55">55</a> + <a href="#section-9.8.8">9.8.8</a>. Example - COPY of a Collection .....................<a href="#page-56">56</a> + <a href="#section-9.9">9.9</a>. MOVE Method ...............................................<a href="#page-56">56</a> + <a href="#section-9.9.1">9.9.1</a>. MOVE for Properties ................................<a href="#page-57">57</a> + <a href="#section-9.9.2">9.9.2</a>. MOVE for Collections ...............................<a href="#page-57">57</a> + <a href="#section-9.9.3">9.9.3</a>. MOVE and the Overwrite Header ......................<a href="#page-58">58</a> + <a href="#section-9.9.4">9.9.4</a>. Status Codes .......................................<a href="#page-59">59</a> + <a href="#section-9.9.5">9.9.5</a>. Example - MOVE of a Non-Collection .................<a href="#page-60">60</a> + <a href="#section-9.9.6">9.9.6</a>. Example - MOVE of a Collection .....................<a href="#page-60">60</a> + <a href="#section-9.10">9.10</a>. LOCK Method ..............................................<a href="#page-61">61</a> + <a href="#section-9.10.1">9.10.1</a>. Creating a Lock on an Existing Resource ...........<a href="#page-61">61</a> + <a href="#section-9.10.2">9.10.2</a>. Refreshing Locks ..................................<a href="#page-62">62</a> + <a href="#section-9.10.3">9.10.3</a>. Depth and Locking .................................<a href="#page-62">62</a> + <a href="#section-9.10.4">9.10.4</a>. Locking Unmapped URLs .............................<a href="#page-63">63</a> + <a href="#section-9.10.5">9.10.5</a>. Lock Compatibility Table ..........................<a href="#page-63">63</a> + <a href="#section-9.10.6">9.10.6</a>. LOCK Responses ....................................<a href="#page-63">63</a> + <a href="#section-9.10.7">9.10.7</a>. Example - Simple Lock Request .....................<a href="#page-64">64</a> + <a href="#section-9.10.8">9.10.8</a>. Example - Refreshing a Write Lock .................<a href="#page-65">65</a> + <a href="#section-9.10.9">9.10.9</a>. Example - Multi-Resource Lock Request .............<a href="#page-66">66</a> + <a href="#section-9.11">9.11</a>. UNLOCK Method ............................................<a href="#page-68">68</a> + <a href="#section-9.11.1">9.11.1</a>. Status Codes ......................................<a href="#page-68">68</a> + + + +<span class="grey">Dusseault Standards Track [Page 3]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-4" id="page-4" href="#page-4" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + <a href="#section-9.11.2">9.11.2</a>. Example - UNLOCK ..................................<a href="#page-69">69</a> + <a href="#section-10">10</a>. HTTP Headers for Distributed Authoring ........................<a href="#page-69">69</a> + <a href="#section-10.1">10.1</a>. DAV Header ...............................................<a href="#page-69">69</a> + <a href="#section-10.2">10.2</a>. Depth Header .............................................<a href="#page-70">70</a> + <a href="#section-10.3">10.3</a>. Destination Header .......................................<a href="#page-71">71</a> + <a href="#section-10.4">10.4</a>. If Header ................................................<a href="#page-72">72</a> + <a href="#section-10.4.1">10.4.1</a>. Purpose ...........................................<a href="#page-72">72</a> + <a href="#section-10.4.2">10.4.2</a>. Syntax ............................................<a href="#page-72">72</a> + <a href="#section-10.4.3">10.4.3</a>. List Evaluation ...................................<a href="#page-73">73</a> + <a href="#section-10.4.4">10.4.4</a>. Matching State Tokens and ETags ...................<a href="#page-74">74</a> + <a href="#section-10.4.5">10.4.5</a>. If Header and Non-DAV-Aware Proxies ...............<a href="#page-74">74</a> + <a href="#section-10.4.6">10.4.6</a>. Example - No-tag Production .......................<a href="#page-75">75</a> + <a href="#section-10.4.7">10.4.7</a>. Example - Using "Not" with No-tag Production ......<a href="#page-75">75</a> + 10.4.8. Example - Causing a Condition to Always + Evaluate to True ..................................<a href="#page-75">75</a> + <a href="#section-10.4.9">10.4.9</a>. Example - Tagged List If Header in COPY ...........<a href="#page-76">76</a> + 10.4.10. Example - Matching Lock Tokens with + Collection Locks .................................<a href="#page-76">76</a> + <a href="#section-10.4.11">10.4.11</a>. Example - Matching ETags on Unmapped URLs ........<a href="#page-76">76</a> + <a href="#section-10.5">10.5</a>. Lock-Token Header ........................................<a href="#page-77">77</a> + <a href="#section-10.6">10.6</a>. Overwrite Header .........................................<a href="#page-77">77</a> + <a href="#section-10.7">10.7</a>. Timeout Request Header ...................................<a href="#page-78">78</a> + <a href="#section-11">11</a>. Status Code Extensions to HTTP/1.1 ............................<a href="#page-78">78</a> + <a href="#section-11.1">11.1</a>. 207 Multi-Status .........................................<a href="#page-78">78</a> + <a href="#section-11.2">11.2</a>. 422 Unprocessable Entity .................................<a href="#page-78">78</a> + <a href="#section-11.3">11.3</a>. 423 Locked ...............................................<a href="#page-78">78</a> + <a href="#section-11.4">11.4</a>. 424 Failed Dependency ....................................<a href="#page-79">79</a> + <a href="#section-11.5">11.5</a>. 507 Insufficient Storage .................................<a href="#page-79">79</a> + <a href="#section-12">12</a>. Use of HTTP Status Codes ......................................<a href="#page-79">79</a> + <a href="#section-12.1">12.1</a>. 412 Precondition Failed ..................................<a href="#page-79">79</a> + <a href="#section-12.2">12.2</a>. 414 Request-URI Too Long .................................<a href="#page-79">79</a> + <a href="#section-13">13</a>. Multi-Status Response .........................................<a href="#page-80">80</a> + <a href="#section-13.1">13.1</a>. Response Headers .........................................<a href="#page-80">80</a> + <a href="#section-13.2">13.2</a>. Handling Redirected Child Resources ......................<a href="#page-81">81</a> + <a href="#section-13.3">13.3</a>. Internal Status Codes ....................................<a href="#page-81">81</a> + <a href="#section-14">14</a>. XML Element Definitions .......................................<a href="#page-81">81</a> + <a href="#section-14.1">14.1</a>. activelock XML Element ...................................<a href="#page-81">81</a> + <a href="#section-14.2">14.2</a>. allprop XML Element ......................................<a href="#page-82">82</a> + <a href="#section-14.3">14.3</a>. collection XML Element ...................................<a href="#page-82">82</a> + <a href="#section-14.4">14.4</a>. depth XML Element ........................................<a href="#page-82">82</a> + <a href="#section-14.5">14.5</a>. error XML Element ........................................<a href="#page-82">82</a> + <a href="#section-14.6">14.6</a>. exclusive XML Element ....................................<a href="#page-83">83</a> + <a href="#section-14.7">14.7</a>. href XML Element .........................................<a href="#page-83">83</a> + <a href="#section-14.8">14.8</a>. include XML Element ......................................<a href="#page-83">83</a> + <a href="#section-14.9">14.9</a>. location XML Element .....................................<a href="#page-83">83</a> + <a href="#section-14.10">14.10</a>. lockentry XML Element ...................................<a href="#page-84">84</a> + <a href="#section-14.11">14.11</a>. lockinfo XML Element ....................................<a href="#page-84">84</a> + <a href="#section-14.12">14.12</a>. lockroot XML Element ....................................<a href="#page-84">84</a> + + + +<span class="grey">Dusseault Standards Track [Page 4]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-5" id="page-5" href="#page-5" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + <a href="#section-14.13">14.13</a>. lockscope XML Element ...................................<a href="#page-84">84</a> + <a href="#section-14.14">14.14</a>. locktoken XML Element ...................................<a href="#page-85">85</a> + <a href="#section-14.15">14.15</a>. locktype XML Element ....................................<a href="#page-85">85</a> + <a href="#section-14.16">14.16</a>. multistatus XML Element .................................<a href="#page-85">85</a> + <a href="#section-14.17">14.17</a>. owner XML Element .......................................<a href="#page-85">85</a> + <a href="#section-14.18">14.18</a>. prop XML Element ........................................<a href="#page-86">86</a> + <a href="#section-14.19">14.19</a>. propertyupdate XML Element ..............................<a href="#page-86">86</a> + <a href="#section-14.20">14.20</a>. propfind XML Element ....................................<a href="#page-86">86</a> + <a href="#section-14.21">14.21</a>. propname XML Element ....................................<a href="#page-87">87</a> + <a href="#section-14.22">14.22</a>. propstat XML Element ....................................<a href="#page-87">87</a> + <a href="#section-14.23">14.23</a>. remove XML Element ......................................<a href="#page-87">87</a> + <a href="#section-14.24">14.24</a>. response XML Element ....................................<a href="#page-88">88</a> + <a href="#section-14.25">14.25</a>. responsedescription XML Element .........................<a href="#page-88">88</a> + <a href="#section-14.26">14.26</a>. set XML Element .........................................<a href="#page-88">88</a> + <a href="#section-14.27">14.27</a>. shared XML Element ......................................<a href="#page-89">89</a> + <a href="#section-14.28">14.28</a>. status XML Element ......................................<a href="#page-89">89</a> + <a href="#section-14.29">14.29</a>. timeout XML Element .....................................<a href="#page-89">89</a> + <a href="#section-14.30">14.30</a>. write XML Element .......................................<a href="#page-89">89</a> + <a href="#section-15">15</a>. DAV Properties ................................................<a href="#page-90">90</a> + <a href="#section-16">16</a>. Precondition/Postcondition XML Elements .......................<a href="#page-98">98</a> + <a href="#section-17">17</a>. XML Extensibility in DAV .....................................<a href="#page-101">101</a> + <a href="#section-18">18</a>. DAV Compliance Classes .......................................<a href="#page-103">103</a> + <a href="#section-18.1">18.1</a>. Class 1 .................................................<a href="#page-103">103</a> + <a href="#section-18.2">18.2</a>. Class 2 .................................................<a href="#page-103">103</a> + <a href="#section-18.3">18.3</a>. Class 3 .................................................<a href="#page-103">103</a> + <a href="#section-19">19</a>. Internationalization Considerations ..........................<a href="#page-104">104</a> + <a href="#section-20">20</a>. Security Considerations ......................................<a href="#page-105">105</a> + <a href="#section-20.1">20.1</a>. Authentication of Clients ...............................<a href="#page-105">105</a> + <a href="#section-20.2">20.2</a>. Denial of Service .......................................<a href="#page-106">106</a> + <a href="#section-20.3">20.3</a>. Security through Obscurity ..............................<a href="#page-106">106</a> + <a href="#section-20.4">20.4</a>. Privacy Issues Connected to Locks .......................<a href="#page-106">106</a> + <a href="#section-20.5">20.5</a>. Privacy Issues Connected to Properties ..................<a href="#page-107">107</a> + <a href="#section-20.6">20.6</a>. Implications of XML Entities ............................<a href="#page-107">107</a> + <a href="#section-20.7">20.7</a>. Risks Connected with Lock Tokens ........................<a href="#page-108">108</a> + <a href="#section-20.8">20.8</a>. Hosting Malicious Content ...............................<a href="#page-108">108</a> + <a href="#section-21">21</a>. IANA Considerations ..........................................<a href="#page-109">109</a> + <a href="#section-21.1">21.1</a>. New URI Schemes .........................................<a href="#page-109">109</a> + <a href="#section-21.2">21.2</a>. XML Namespaces ..........................................<a href="#page-109">109</a> + <a href="#section-21.3">21.3</a>. Message Header Fields ...................................<a href="#page-109">109</a> + <a href="#section-21.3.1">21.3.1</a>. DAV ..............................................<a href="#page-109">109</a> + <a href="#section-21.3.2">21.3.2</a>. Depth ............................................<a href="#page-110">110</a> + <a href="#section-21.3.3">21.3.3</a>. Destination ......................................<a href="#page-110">110</a> + <a href="#section-21.3.4">21.3.4</a>. If ...............................................<a href="#page-110">110</a> + <a href="#section-21.3.5">21.3.5</a>. Lock-Token .......................................<a href="#page-110">110</a> + <a href="#section-21.3.6">21.3.6</a>. Overwrite ........................................<a href="#page-111">111</a> + <a href="#section-21.3.7">21.3.7</a>. Timeout ..........................................<a href="#page-111">111</a> + <a href="#section-21.4">21.4</a>. HTTP Status Codes .......................................<a href="#page-111">111</a> + <a href="#section-22">22</a>. Acknowledgements .............................................<a href="#page-112">112</a> + + + +<span class="grey">Dusseault Standards Track [Page 5]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-6" id="page-6" href="#page-6" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + <a href="#section-23">23</a>. Contributors to This Specification ...........................<a href="#page-113">113</a> + <a href="#section-24">24</a>. Authors of <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a> ..........................................<a href="#page-113">113</a> + <a href="#section-25">25</a>. References ...................................................<a href="#page-114">114</a> + <a href="#section-25.1">25.1</a>. Normative References.....................................<a href="#page-114">114</a> + <a href="#section-25.2">25.2</a>. Informative References ..................................<a href="#page-115">115</a> + <a href="#appendix-A">Appendix A</a>. Notes on Processing XML Elements ....................<a href="#page-117">117</a> + <a href="#appendix-A.1">A.1</a>. Notes on Empty XML Elements ..............................<a href="#page-117">117</a> + <a href="#appendix-A.2">A.2</a>. Notes on Illegal XML Processing ..........................<a href="#page-117">117</a> + <a href="#appendix-A.3">A.3</a>. Example - XML Syntax Error ...............................<a href="#page-117">117</a> + <a href="#appendix-A.4">A.4</a>. Example - Unexpected XML Element .........................<a href="#page-118">118</a> + <a href="#appendix-B">Appendix B</a>. Notes on HTTP Client Compatibility ...................<a href="#page-119">119</a> + <a href="#appendix-C">Appendix C</a>. The 'opaquelocktoken' Scheme and URIs ................<a href="#page-120">120</a> + <a href="#appendix-D">Appendix D</a>. Lock-null Resources ..................................<a href="#page-120">120</a> + <a href="#appendix-D.1">D.1</a>. Guidance for Clients Using LOCK to Create Resources ......<a href="#page-121">121</a> + <a href="#appendix-E">Appendix E</a>. Guidance for Clients Desiring to Authenticate ........<a href="#page-121">121</a> + <a href="#appendix-F">Appendix F</a>. Summary of Changes from <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a> .....................<a href="#page-123">123</a> + <a href="#appendix-F.1">F.1</a>. Changes for Both Client and Server Implementations .......<a href="#page-123">123</a> + <a href="#appendix-F.2">F.2</a>. Changes for Server Implementations .......................<a href="#page-125">125</a> + <a href="#appendix-F.3">F.3</a>. Other Changes ............................................<a href="#page-126">126</a> + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 6]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-7" id="page-7" href="#page-7" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="section-1" href="#section-1">1</a>. Introduction</h2></span> + + This document describes an extension to the HTTP/1.1 protocol that + allows clients to perform remote Web content authoring operations. + This extension provides a coherent set of methods, headers, request + entity body formats, and response entity body formats that provide + operations for: + + Properties: The ability to create, remove, and query information + about Web pages, such as their authors, creation dates, etc. + + Collections: The ability to create sets of documents and to retrieve + a hierarchical membership listing (like a directory listing in a file + system). + + Locking: The ability to keep more than one person from working on a + document at the same time. This prevents the "lost update problem", + in which modifications are lost as first one author, then another, + writes changes without merging the other author's changes. + + Namespace Operations: The ability to instruct the server to copy and + move Web resources, operations that change the mapping from URLs to + resources. + + Requirements and rationale for these operations are described in a + companion document, "Requirements for a Distributed Authoring and + Versioning Protocol for the World Wide Web" [<a href="http://tools.ietf.org/html/rfc2291" title="" requirements for a distributed authoring and versioning protocol the world wide web>RFC2291</a>]. + + This document does not specify the versioning operations suggested by + [<a href="http://tools.ietf.org/html/rfc2291" title="" requirements for a distributed authoring and versioning protocol the world wide web>RFC2291</a>]. That work was done in a separate document, "Versioning + Extensions to WebDAV" [<a href="http://tools.ietf.org/html/rfc3253" title="" versioning extensions to webdav distributed authoring and>RFC3253</a>]. + + The sections below provide a detailed introduction to various WebDAV + abstractions: resource properties (<a href="#section-4">Section 4</a>), collections of + resources (<a href="#section-5">Section 5</a>), locks (<a href="#section-6">Section 6</a>) in general, and write locks + (<a href="#section-7">Section 7</a>) specifically. + + These abstractions are manipulated by the WebDAV-specific HTTP + methods (<a href="#section-9">Section 9</a>) and the extra HTTP headers (<a href="#section-10">Section 10</a>) used with + WebDAV methods. General considerations for handling HTTP requests + and responses in WebDAV are found in <a href="#section-8">Section 8</a>. + + While the status codes provided by HTTP/1.1 are sufficient to + describe most error conditions encountered by WebDAV methods, there + are some errors that do not fall neatly into the existing categories. + This specification defines extra status codes developed for WebDAV + methods (<a href="#section-11">Section 11</a>) and describes existing HTTP status codes + (<a href="#section-12">Section 12</a>) as used in WebDAV. Since some WebDAV methods may + + + +<span class="grey">Dusseault Standards Track [Page 7]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-8" id="page-8" href="#page-8" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + operate over many resources, the Multi-Status response (<a href="#section-13">Section 13</a>) + has been introduced to return status information for multiple + resources. Finally, this version of WebDAV introduces precondition + and postcondition (<a href="#section-16">Section 16</a>) XML elements in error response bodies. + + WebDAV uses XML ([<a href="#ref-REC-XML" title="" extensible markup language edition>REC-XML</a>]) for property names and some values, and + also uses XML to marshal complicated requests and responses. This + specification contains DTD and text definitions of all properties + (<a href="#section-15">Section 15</a>) and all other XML elements (<a href="#section-14">Section 14</a>) used in + marshalling. WebDAV includes a few special rules on extending WebDAV + XML marshalling in backwards-compatible ways (<a href="#section-17">Section 17</a>). + + Finishing off the specification are sections on what it means for a + resource to be compliant with this specification (<a href="#section-18">Section 18</a>), on + internationalization support (<a href="#section-19">Section 19</a>), and on security + (<a href="#section-20">Section 20</a>). + +<span class="h2"><h2><a class="selflink" name="section-2" href="#section-2">2</a>. Notational Conventions</h2></span> + + Since this document describes a set of extensions to the HTTP/1.1 + protocol, the augmented BNF used herein to describe protocol elements + is exactly the same as described in <a href="http://tools.ietf.org/html/rfc2616#section-2.1">Section 2.1 of [RFC2616]</a>, + including the rules about implied linear whitespace. Since this + augmented BNF uses the basic production rules provided in <a href="http://tools.ietf.org/html/rfc2616#section-2.2">Section 2.2 + of [RFC2616]</a>, these rules apply to this document as well. Note this + is not the standard BNF syntax used in other RFCs. + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this + document are to be interpreted as described in [<a href="http://tools.ietf.org/html/rfc2119" title="" key words for use in rfcs to indicate requirement levels>RFC2119</a>]. + + Note that in natural language, a property like the "creationdate" + property in the "DAV:" XML namespace is sometimes referred to as + "DAV:creationdate" for brevity. + +<span class="h2"><h2><a class="selflink" name="section-3" href="#section-3">3</a>. Terminology</h2></span> + + URI/URL - A Uniform Resource Identifier and Uniform Resource Locator, + respectively. These terms (and the distinction between them) are + defined in [<a href="http://tools.ietf.org/html/rfc3986" title="" uniform resource identifier generic syntax>RFC3986</a>]. + + URI/URL Mapping - A relation between an absolute URI and a resource. + Since a resource can represent items that are not network + retrievable, as well as those that are, it is possible for a resource + to have zero, one, or many URI mappings. Mapping a resource to an + "http" scheme URI makes it possible to submit HTTP protocol requests + to the resource using the URI. + + + + +<span class="grey">Dusseault Standards Track [Page 8]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-9" id="page-9" href="#page-9" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Path Segment - Informally, the characters found between slashes ("/") + in a URI. Formally, as defined in <a href="http://tools.ietf.org/html/rfc3986#section-3.3">Section 3.3 of [RFC3986]</a>. + + Collection - Informally, a resource that also acts as a container of + references to child resources. Formally, a resource that contains a + set of mappings between path segments and resources and meets the + requirements defined in <a href="#section-5">Section 5</a>. + + Internal Member (of a Collection) - Informally, a child resource of a + collection. Formally, a resource referenced by a path segment + mapping contained in the collection. + + Internal Member URL (of a Collection) - A URL of an internal member, + consisting of the URL of the collection (including trailing slash) + plus the path segment identifying the internal member. + + Member (of a Collection) - Informally, a "descendant" of a + collection. Formally, an internal member of the collection, or, + recursively, a member of an internal member. + + Member URL (of a Collection) - A URL that is either an internal + member URL of the collection itself, or is an internal member URL of + a member of that collection. + + Property - A name/value pair that contains descriptive information + about a resource. + + Live Property - A property whose semantics and syntax are enforced by + the server. For example, the live property DAV:getcontentlength has + its value, the length of the entity returned by a GET request, + automatically calculated by the server. + + Dead Property - A property whose semantics and syntax are not + enforced by the server. The server only records the value of a dead + property; the client is responsible for maintaining the consistency + of the syntax and semantics of a dead property. + + Principal - A distinct human or computational actor that initiates + access to network resources. + + State Token - A URI that represents a state of a resource. Lock + tokens are the only state tokens defined in this specification. + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 9]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-10" id="page-10" href="#page-10" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="section-4" href="#section-4">4</a>. Data Model for Resource Properties</h2></span> + +<span class="h3"><h3><a class="selflink" name="section-4.1" href="#section-4.1">4.1</a>. The Resource Property Model</h3></span> + + Properties are pieces of data that describe the state of a resource. + Properties are data about data. + + Properties are used in distributed authoring environments to provide + for efficient discovery and management of resources. For example, a + 'subject' property might allow for the indexing of all resources by + their subject, and an 'author' property might allow for the discovery + of what authors have written which documents. + + The DAV property model consists of name/value pairs. The name of a + property identifies the property's syntax and semantics, and provides + an address by which to refer to its syntax and semantics. + + There are two categories of properties: "live" and "dead". A live + property has its syntax and semantics enforced by the server. Live + properties include cases where a) the value of a property is + protected and maintained by the server, and b) the value of the + property is maintained by the client, but the server performs syntax + checking on submitted values. All instances of a given live property + MUST comply with the definition associated with that property name. + A dead property has its syntax and semantics enforced by the client; + the server merely records the value of the property verbatim. + +<span class="h3"><h3><a class="selflink" name="section-4.2" href="#section-4.2">4.2</a>. Properties and HTTP Headers</h3></span> + + Properties already exist, in a limited sense, in HTTP message + headers. However, in distributed authoring environments, a + relatively large number of properties are needed to describe the + state of a resource, and setting/returning them all through HTTP + headers is inefficient. Thus, a mechanism is needed that allows a + principal to identify a set of properties in which the principal is + interested and to set or retrieve just those properties. + +<span class="h3"><h3><a class="selflink" name="section-4.3" href="#section-4.3">4.3</a>. Property Values</h3></span> + + The value of a property is always a (well-formed) XML fragment. + + XML has been chosen because it is a flexible, self-describing, + structured data format that supports rich schema definitions, and + because of its support for multiple character sets. XML's self- + describing nature allows any property's value to be extended by + adding elements. Clients will not break when they encounter + extensions because they will still have the data specified in the + original schema and MUST ignore elements they do not understand. + + + +<span class="grey">Dusseault Standards Track [Page 10]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-11" id="page-11" href="#page-11" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + XML's support for multiple character sets allows any human-readable + property to be encoded and read in a character set familiar to the + user. XML's support for multiple human languages, using the "xml: + lang" attribute, handles cases where the same character set is + employed by multiple human languages. Note that xml:lang scope is + recursive, so an xml:lang attribute on any element containing a + property name element applies to the property value unless it has + been overridden by a more locally scoped attribute. Note that a + property only has one value, in one language (or language MAY be left + undefined); a property does not have multiple values in different + languages or a single value in multiple languages. + + A property is always represented with an XML element consisting of + the property name, called the "property name element". The simplest + example is an empty property, which is different from a property that + does not exist: + + <R:title xmlns:R="http://www.example.com/ns/"></R:title> + + The value of the property appears inside the property name element. + The value may be any kind of well-formed XML content, including both + text-only and mixed content. Servers MUST preserve the following XML + Information Items (using the terminology from [<a href="#ref-REC-XML-INFOSET" title="" xml information set edition>REC-XML-INFOSET</a>]) in + storage and transmission of dead properties: + + For the property name Element Information Item itself: + + [namespace name] + + [local name] + + [<a name="ref-attributes" id="ref-attributes">attributes</a>] named "xml:lang" or any such attribute in scope + + [<a name="ref-children" id="ref-children">children</a>] of type element or character + + On all Element Information Items in the property value: + + [namespace name] + + [local name] + + [<a name="ref-attributes" id="ref-attributes">attributes</a>] + + [<a href="#ref-children">children</a>] of type element or character + + + + + + + +<span class="grey">Dusseault Standards Track [Page 11]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-12" id="page-12" href="#page-12" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + On Attribute Information Items in the property value: + + [namespace name] + + [local name] + + [normalized value] + + On Character Information Items in the property value: + + [character code] + + Since prefixes are used in some XML vocabularies (XPath and XML + Schema, for example), servers SHOULD preserve, for any Information + Item in the value: + + [<a name="ref-prefix" id="ref-prefix">prefix</a>] + + XML Infoset attributes not listed above MAY be preserved by the + server, but clients MUST NOT rely on them being preserved. The above + rules would also apply by default to live properties, unless defined + otherwise. + + Servers MUST ignore the XML attribute xml:space if present and never + use it to change whitespace handling. Whitespace in property values + is significant. + +<span class="h4"><h4><a class="selflink" name="section-4.3.1" href="#section-4.3.1">4.3.1</a>. Example - Property with Mixed Content</h4></span> + + Consider a dead property 'author' created by the client as follows: + + <D:prop xml:lang="en" xmlns:D="DAV:"> + <x:author xmlns:x='http://example.com/ns'> + <x:name>Jane Doe</x:name> + <!-- Jane's contact info --> + <x:uri type='email' + added='2005-11-26'>mailto:jane.doe@example.com</x:uri> + <x:uri type='web' + added='2005-11-27'>http://www.example.com</x:uri> + <x:notes xmlns:h='http://www.w3.org/1999/xhtml'> + Jane has been working way <h:em>too</h:em> long on the + long-awaited revision of <![CDATA[<<a href="http://tools.ietf.org/html/rfc2518">RFC2518</a>>]]>. + </x:notes> + </x:author> + </D:prop> + + + + + + +<span class="grey">Dusseault Standards Track [Page 12]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-13" id="page-13" href="#page-13" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + When this property is requested, a server might return: + + <D:prop xmlns:D='DAV:'><author + xml:lang='en' + xmlns:x='http://example.com/ns' + xmlns='http://example.com/ns' + xmlns:h='http://www.w3.org/1999/xhtml'> + <x:name>Jane Doe</x:name> + <x:uri added="2005-11-26" type="email" + >mailto:jane.doe@example.com</x:uri> + <x:uri added="2005-11-27" type="web" + >http://www.example.com</x:uri> + <x:notes> + Jane has been working way <h:em>too</h:em> long on the + long-awaited revision of &lt;<a href="http://tools.ietf.org/html/rfc2518">RFC2518</a>&gt;. + </x:notes> + </author> + </D:prop> + + Note in this example: + + o The [<a href="#ref-prefix">prefix</a>] for the property name itself was not preserved, being + non-significant, whereas all other [<a href="#ref-prefix">prefix</a>] values have been + preserved, + + o attribute values have been rewritten with double quotes instead of + single quotes (quoting style is not significant), and attribute + order has not been preserved, + + o the xml:lang attribute has been returned on the property name + element itself (it was in scope when the property was set, but the + exact position in the response is not considered significant as + long as it is in scope), + + o whitespace between tags has been preserved everywhere (whitespace + between attributes not so), + + o CDATA encapsulation was replaced with character escaping (the + reverse would also be legal), + + o the comment item was stripped (as would have been a processing + instruction item). + + Implementation note: there are cases such as editing scenarios where + clients may require that XML content is preserved character by + character (such as attribute ordering or quoting style). In this + case, clients should consider using a text-only property value by + escaping all characters that have a special meaning in XML parsing. + + + +<span class="grey">Dusseault Standards Track [Page 13]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-14" id="page-14" href="#page-14" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-4.4" href="#section-4.4">4.4</a>. Property Names</h3></span> + + A property name is a universally unique identifier that is associated + with a schema that provides information about the syntax and + semantics of the property. + + Because a property's name is universally unique, clients can depend + upon consistent behavior for a particular property across multiple + resources, on the same and across different servers, so long as that + property is "live" on the resources in question, and the + implementation of the live property is faithful to its definition. + + The XML namespace mechanism, which is based on URIs ([<a href="http://tools.ietf.org/html/rfc3986" title="" uniform resource identifier generic syntax>RFC3986</a>]), is + used to name properties because it prevents namespace collisions and + provides for varying degrees of administrative control. + + The property namespace is flat; that is, no hierarchy of properties + is explicitly recognized. Thus, if a property A and a property A/B + exist on a resource, there is no recognition of any relationship + between the two properties. It is expected that a separate + specification will eventually be produced that will address issues + relating to hierarchical properties. + + Finally, it is not possible to define the same property twice on a + single resource, as this would cause a collision in the resource's + property namespace. + +<span class="h3"><h3><a class="selflink" name="section-4.5" href="#section-4.5">4.5</a>. Source Resources and Output Resources</h3></span> + + Some HTTP resources are dynamically generated by the server. For + these resources, there presumably exists source code somewhere + governing how that resource is generated. The relationship of source + files to output HTTP resources may be one to one, one to many, many + to one, or many to many. There is no mechanism in HTTP to determine + whether a resource is even dynamic, let alone where its source files + exist or how to author them. Although this problem would usefully be + solved, interoperable WebDAV implementations have been widely + deployed without actually solving this problem, by dealing only with + static resources. Thus, the source vs. output problem is not solved + in this specification and has been deferred to a separate document. + +<span class="h2"><h2><a class="selflink" name="section-5" href="#section-5">5</a>. Collections of Web Resources</h2></span> + + This section provides a description of a type of Web resource, the + collection, and discusses its interactions with the HTTP URL + namespace and with HTTP methods. The purpose of a collection + resource is to model collection-like objects (e.g., file system + directories) within a server's namespace. + + + +<span class="grey">Dusseault Standards Track [Page 14]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-15" id="page-15" href="#page-15" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + All DAV-compliant resources MUST support the HTTP URL namespace model + specified herein. + +<span class="h3"><h3><a class="selflink" name="section-5.1" href="#section-5.1">5.1</a>. HTTP URL Namespace Model</h3></span> + + The HTTP URL namespace is a hierarchical namespace where the + hierarchy is delimited with the "/" character. + + An HTTP URL namespace is said to be consistent if it meets the + following conditions: for every URL in the HTTP hierarchy there + exists a collection that contains that URL as an internal member URL. + The root, or top-level collection of the namespace under + consideration, is exempt from the previous rule. The top-level + collection of the namespace under consideration is not necessarily + the collection identified by the absolute path '/' -- it may be + identified by one or more path segments (e.g., /servlets/webdav/...) + + Neither HTTP/1.1 nor WebDAV requires that the entire HTTP URL + namespace be consistent -- a WebDAV-compatible resource may not have + a parent collection. However, certain WebDAV methods are prohibited + from producing results that cause namespace inconsistencies. + + As is implicit in [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>] and [<a href="http://tools.ietf.org/html/rfc3986" title="" uniform resource identifier generic syntax>RFC3986</a>], any resource, including + collection resources, MAY be identified by more than one URI. For + example, a resource could be identified by multiple HTTP URLs. + +<span class="h3"><h3><a class="selflink" name="section-5.2" href="#section-5.2">5.2</a>. Collection Resources</h3></span> + + Collection resources differ from other resources in that they also + act as containers. Some HTTP methods apply only to a collection, but + some apply to some or all of the resources inside the container + defined by the collection. When the scope of a method is not clear, + the client can specify what depth to apply. Depth can be either zero + levels (only the collection), one level (the collection and directly + contained resources), or infinite levels (the collection and all + contained resources recursively). + + A collection's state consists of at least a set of mappings between + path segments and resources, and a set of properties on the + collection itself. In this document, a resource B will be said to be + contained in the collection resource A if there is a path segment + mapping that maps to B and that is contained in A. A collection MUST + contain at most one mapping for a given path segment, i.e., it is + illegal to have the same path segment mapped to more than one + resource. + + + + + + +<span class="grey">Dusseault Standards Track [Page 15]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-16" id="page-16" href="#page-16" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Properties defined on collections behave exactly as do properties on + non-collection resources. A collection MAY have additional state + such as entity bodies returned by GET. + + For all WebDAV-compliant resources A and B, identified by URLs "U" + and "V", respectively, such that "V" is equal to "U/SEGMENT", A MUST + be a collection that contains a mapping from "SEGMENT" to B. So, if + resource B with URL "http://example.com/bar/blah" is WebDAV compliant + and if resource A with URL "http://example.com/bar/" is WebDAV + compliant, then resource A must be a collection and must contain + exactly one mapping from "blah" to B. + + Although commonly a mapping consists of a single segment and a + resource, in general, a mapping consists of a set of segments and a + resource. This allows a server to treat a set of segments as + equivalent (i.e., either all of the segments are mapped to the same + resource, or none of the segments are mapped to a resource). For + example, a server that performs case-folding on segments will treat + the segments "ab", "Ab", "aB", and "AB" as equivalent. A client can + then use any of these segments to identify the resource. Note that a + PROPFIND result will select one of these equivalent segments to + identify the mapping, so there will be one PROPFIND response element + per mapping, not one per segment in the mapping. + + Collection resources MAY have mappings to non-WebDAV-compliant + resources in the HTTP URL namespace hierarchy but are not required to + do so. For example, if resource X with URL + "http://example.com/bar/blah" is not WebDAV compliant and resource A + with "URL http://example.com/bar/" identifies a WebDAV collection, + then A may or may not have a mapping from "blah" to X. + + If a WebDAV-compliant resource has no WebDAV-compliant internal + members in the HTTP URL namespace hierarchy, then the WebDAV- + compliant resource is not required to be a collection. + + There is a standing convention that when a collection is referred to + by its name without a trailing slash, the server MAY handle the + request as if the trailing slash were present. In this case, it + SHOULD return a Content-Location header in the response, pointing to + the URL ending with the "/". For example, if a client invokes a + method on http://example.com/blah (no trailing slash), the server may + respond as if the operation were invoked on http://example.com/blah/ + (trailing slash), and should return a Content-Location header with + the value http://example.com/blah/. Wherever a server produces a URL + referring to a collection, the server SHOULD include the trailing + slash. In general, clients SHOULD use the trailing slash form of + collection names. If clients do not use the trailing slash form the + client needs to be prepared to see a redirect response. Clients will + + + +<span class="grey">Dusseault Standards Track [Page 16]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-17" id="page-17" href="#page-17" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + find the DAV:resourcetype property more reliable than the URL to find + out if a resource is a collection. + + Clients MUST be able to support the case where WebDAV resources are + contained inside non-WebDAV resources. For example, if an OPTIONS + response from "http://example.com/servlet/dav/collection" indicates + WebDAV support, the client cannot assume that + "http://example.com/servlet/dav/" or its parent necessarily are + WebDAV collections. + + A typical scenario in which mapped URLs do not appear as members of + their parent collection is the case where a server allows links or + redirects to non-WebDAV resources. For instance, "/col/link" might + not appear as a member of "/col/", although the server would respond + with a 302 status to a GET request to "/col/link"; thus, the URL + "/col/link" would indeed be mapped. Similarly, a dynamically- + generated page might have a URL mapping from "/col/index.html", thus + this resource might respond with a 200 OK to a GET request yet not + appear as a member of "/col/". + + Some mappings to even WebDAV-compliant resources might not appear in + the parent collection. An example for this case are servers that + support multiple alias URLs for each WebDAV-compliant resource. A + server may implement case-insensitive URLs, thus "/col/a" and + "/col/A" identify the same resource, yet only either "a" or "A" is + reported upon listing the members of "/col". In cases where a server + treats a set of segments as equivalent, the server MUST expose only + one preferred segment per mapping, consistently chosen, in PROPFIND + responses. + +<span class="h2"><h2><a class="selflink" name="section-6" href="#section-6">6</a>. Locking</h2></span> + + The ability to lock a resource provides a mechanism for serializing + access to that resource. Using a lock, an authoring client can + provide a reasonable guarantee that another principal will not modify + a resource while it is being edited. In this way, a client can + prevent the "lost update" problem. + + This specification allows locks to vary over two client-specified + parameters, the number of principals involved (exclusive vs. shared) + and the type of access to be granted. This document defines locking + for only one access type, write. However, the syntax is extensible, + and permits the eventual specification of locking for other access + types. + + + + + + + +<span class="grey">Dusseault Standards Track [Page 17]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-18" id="page-18" href="#page-18" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-6.1" href="#section-6.1">6.1</a>. Lock Model</h3></span> + + This section provides a concise model for how locking behaves. Later + sections will provide more detail on some of the concepts and refer + back to these model statements. Normative statements related to LOCK + and UNLOCK method handling can be found in the sections on those + methods, whereas normative statements that cover any method are + gathered here. + + 1. A lock either directly or indirectly locks a resource. + + 2. A resource becomes directly locked when a LOCK request to a URL + of that resource creates a new lock. The "lock-root" of the new + lock is that URL. If at the time of the request, the URL is not + mapped to a resource, a new empty resource is created and + directly locked. + + 3. An exclusive lock (<a href="#section-6.2">Section 6.2</a>) conflicts with any other kind of + lock on the same resource, whether either lock is direct or + indirect. A server MUST NOT create conflicting locks on a + resource. + + 4. For a collection that is locked with a depth-infinity lock L, all + member resources are indirectly locked. Changes in membership of + such a collection affect the set of indirectly locked resources: + + * If a member resource is added to the collection, the new + member resource MUST NOT already have a conflicting lock, + because the new resource MUST become indirectly locked by L. + + * If a member resource stops being a member of the collection, + then the resource MUST no longer be indirectly locked by L. + + 5. Each lock is identified by a single globally unique lock token + (<a href="#section-6.5">Section 6.5</a>). + + 6. An UNLOCK request deletes the lock with the specified lock token. + After a lock is deleted, no resource is locked by that lock. + + 7. A lock token is "submitted" in a request when it appears in an + "If" header (<a href="#section-7">Section 7</a>, "Write Lock", discusses when token + submission is required for write locks). + + 8. If a request causes the lock-root of any lock to become an + unmapped URL, then the lock MUST also be deleted by that request. + + + + + + +<span class="grey">Dusseault Standards Track [Page 18]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-19" id="page-19" href="#page-19" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-6.2" href="#section-6.2">6.2</a>. Exclusive vs. Shared Locks</h3></span> + + The most basic form of lock is an exclusive lock. Exclusive locks + avoid having to deal with content change conflicts, without requiring + any coordination other than the methods described in this + specification. + + However, there are times when the goal of a lock is not to exclude + others from exercising an access right but rather to provide a + mechanism for principals to indicate that they intend to exercise + their access rights. Shared locks are provided for this case. A + shared lock allows multiple principals to receive a lock. Hence any + principal that has both access privileges and a valid lock can use + the locked resource. + + With shared locks, there are two trust sets that affect a resource. + The first trust set is created by access permissions. Principals who + are trusted, for example, may have permission to write to the + resource. Among those who have access permission to write to the + resource, the set of principals who have taken out a shared lock also + must trust each other, creating a (typically) smaller trust set + within the access permission write set. + + Starting with every possible principal on the Internet, in most + situations the vast majority of these principals will not have write + access to a given resource. Of the small number who do have write + access, some principals may decide to guarantee their edits are free + from overwrite conflicts by using exclusive write locks. Others may + decide they trust their collaborators will not overwrite their work + (the potential set of collaborators being the set of principals who + have write permission) and use a shared lock, which informs their + collaborators that a principal may be working on the resource. + + The WebDAV extensions to HTTP do not need to provide all of the + communications paths necessary for principals to coordinate their + activities. When using shared locks, principals may use any out-of- + band communication channel to coordinate their work (e.g., face-to- + face interaction, written notes, post-it notes on the screen, + telephone conversation, email, etc.) The intent of a shared lock is + to let collaborators know who else may be working on a resource. + + Shared locks are included because experience from Web-distributed + authoring systems has indicated that exclusive locks are often too + rigid. An exclusive lock is used to enforce a particular editing + process: take out an exclusive lock, read the resource, perform + edits, write the resource, release the lock. This editing process + has the problem that locks are not always properly released, for + example, when a program crashes or when a lock creator leaves without + + + +<span class="grey">Dusseault Standards Track [Page 19]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-20" id="page-20" href="#page-20" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + unlocking a resource. While both timeouts (<a href="#section-6.6">Section 6.6</a>) and + administrative action can be used to remove an offending lock, + neither mechanism may be available when needed; the timeout may be + long or the administrator may not be available. + + A successful request for a new shared lock MUST result in the + generation of a unique lock associated with the requesting principal. + Thus, if five principals have taken out shared write locks on the + same resource, there will be five locks and five lock tokens, one for + each principal. + +<span class="h3"><h3><a class="selflink" name="section-6.3" href="#section-6.3">6.3</a>. Required Support</h3></span> + + A WebDAV-compliant resource is not required to support locking in any + form. If the resource does support locking, it may choose to support + any combination of exclusive and shared locks for any access types. + + The reason for this flexibility is that locking policy strikes to the + very heart of the resource management and versioning systems employed + by various storage repositories. These repositories require control + over what sort of locking will be made available. For example, some + repositories only support shared write locks, while others only + provide support for exclusive write locks, while yet others use no + locking at all. As each system is sufficiently different to merit + exclusion of certain locking features, this specification leaves + locking as the sole axis of negotiation within WebDAV. + +<span class="h3"><h3><a class="selflink" name="section-6.4" href="#section-6.4">6.4</a>. Lock Creator and Privileges</h3></span> + + The creator of a lock has special privileges to use the lock to + modify the resource. When a locked resource is modified, a server + MUST check that the authenticated principal matches the lock creator + (in addition to checking for valid lock token submission). + + The server MAY allow privileged users other than the lock creator to + destroy a lock (for example, the resource owner or an administrator). + The 'unlock' privilege in [<a href="http://tools.ietf.org/html/rfc3744" title="" web distributed authoring and versioning access control protocol>RFC3744</a>] was defined to provide that + permission. + + There is no requirement for servers to accept LOCK requests from all + users or from anonymous users. + + Note that having a lock does not confer full privilege to modify the + locked resource. Write access and other privileges MUST be enforced + through normal privilege or authentication mechanisms, not based on + the possible obscurity of lock token values. + + + + + +<span class="grey">Dusseault Standards Track [Page 20]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-21" id="page-21" href="#page-21" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-6.5" href="#section-6.5">6.5</a>. Lock Tokens</h3></span> + + A lock token is a type of state token that identifies a particular + lock. Each lock has exactly one unique lock token generated by the + server. Clients MUST NOT attempt to interpret lock tokens in any + way. + + Lock token URIs MUST be unique across all resources for all time. + This uniqueness constraint allows lock tokens to be submitted across + resources and servers without fear of confusion. Since lock tokens + are unique, a client MAY submit a lock token in an If header on a + resource other than the one that returned it. + + When a LOCK operation creates a new lock, the new lock token is + returned in the Lock-Token response header defined in <a href="#section-10.5">Section 10.5</a>, + and also in the body of the response. + + Servers MAY make lock tokens publicly readable (e.g., in the DAV: + lockdiscovery property). One use case for making lock tokens + readable is so that a long-lived lock can be removed by the resource + owner (the client that obtained the lock might have crashed or + disconnected before cleaning up the lock). Except for the case of + using UNLOCK under user guidance, a client SHOULD NOT use a lock + token created by another client instance. + + This specification encourages servers to create Universally Unique + Identifiers (UUIDs) for lock tokens, and to use the URI form defined + by "A Universally Unique Identifier (UUID) URN Namespace" + ([<a href="http://tools.ietf.org/html/rfc4122" title="" a universally unique identifier urn namespace>RFC4122</a>]). However, servers are free to use any URI (e.g., from + another scheme) so long as it meets the uniqueness requirements. For + example, a valid lock token might be constructed using the + "opaquelocktoken" scheme defined in <a href="#appendix-C">Appendix C</a>. + + Example: "urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6" + +<span class="h3"><h3><a class="selflink" name="section-6.6" href="#section-6.6">6.6</a>. Lock Timeout</h3></span> + + A lock MAY have a limited lifetime. The lifetime is suggested by the + client when creating or refreshing the lock, but the server + ultimately chooses the timeout value. Timeout is measured in seconds + remaining until lock expiration. + + The timeout counter MUST be restarted if a refresh lock request is + successful (see <a href="#section-9.10.2">Section 9.10.2</a>). The timeout counter SHOULD NOT be + restarted at any other time. + + If the timeout expires, then the lock SHOULD be removed. In this + case the server SHOULD act as if an UNLOCK method was executed by the + + + +<span class="grey">Dusseault Standards Track [Page 21]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-22" id="page-22" href="#page-22" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + server on the resource using the lock token of the timed-out lock, + performed with its override authority. + + Servers are advised to pay close attention to the values submitted by + clients, as they will be indicative of the type of activity the + client intends to perform. For example, an applet running in a + browser may need to lock a resource, but because of the instability + of the environment within which the applet is running, the applet may + be turned off without warning. As a result, the applet is likely to + ask for a relatively small timeout value so that if the applet dies, + the lock can be quickly harvested. However, a document management + system is likely to ask for an extremely long timeout because its + user may be planning on going offline. + + A client MUST NOT assume that just because the timeout has expired, + the lock has immediately been removed. + + Likewise, a client MUST NOT assume that just because the timeout has + not expired, the lock still exists. Clients MUST assume that locks + can arbitrarily disappear at any time, regardless of the value given + in the Timeout header. The Timeout header only indicates the + behavior of the server if extraordinary circumstances do not occur. + For example, a sufficiently privileged user may remove a lock at any + time, or the system may crash in such a way that it loses the record + of the lock's existence. + +<span class="h3"><h3><a class="selflink" name="section-6.7" href="#section-6.7">6.7</a>. Lock Capability Discovery</h3></span> + + Since server lock support is optional, a client trying to lock a + resource on a server can either try the lock and hope for the best, + or perform some form of discovery to determine what lock capabilities + the server supports. This is known as lock capability discovery. A + client can determine what lock types the server supports by + retrieving the DAV:supportedlock property. + + Any DAV-compliant resource that supports the LOCK method MUST support + the DAV:supportedlock property. + +<span class="h3"><h3><a class="selflink" name="section-6.8" href="#section-6.8">6.8</a>. Active Lock Discovery</h3></span> + + If another principal locks a resource that a principal wishes to + access, it is useful for the second principal to be able to find out + who the first principal is. For this purpose the DAV:lockdiscovery + property is provided. This property lists all outstanding locks, + describes their type, and MAY even provide the lock tokens. + + Any DAV-compliant resource that supports the LOCK method MUST support + the DAV:lockdiscovery property. + + + +<span class="grey">Dusseault Standards Track [Page 22]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-23" id="page-23" href="#page-23" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="section-7" href="#section-7">7</a>. Write Lock</h2></span> + + This section describes the semantics specific to the write lock type. + The write lock is a specific instance of a lock type, and is the only + lock type described in this specification. + + An exclusive write lock protects a resource: it prevents changes by + any principal other than the lock creator and in any case where the + lock token is not submitted (e.g., by a client process other than the + one holding the lock). + + Clients MUST submit a lock-token they are authorized to use in any + request that modifies a write-locked resource. The list of + modifications covered by a write-lock include: + + 1. A change to any of the following aspects of any write-locked + resource: + + * any variant, + + * any dead property, + + * any live property that is lockable (a live property is + lockable unless otherwise defined.) + + 2. For collections, any modification of an internal member URI. An + internal member URI of a collection is considered to be modified + if it is added, removed, or identifies a different resource. + More discussion on write locks and collections is found in + <a href="#section-7.4">Section 7.4</a>. + + 3. A modification of the mapping of the root of the write lock, + either to another resource or to no resource (e.g., DELETE). + + Of the methods defined in HTTP and WebDAV, PUT, POST, PROPPATCH, + LOCK, UNLOCK, MOVE, COPY (for the destination resource), DELETE, and + MKCOL are affected by write locks. All other HTTP/WebDAV methods + defined so far -- GET in particular -- function independently of a + write lock. + + The next few sections describe in more specific terms how write locks + interact with various operations. + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 23]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-24" id="page-24" href="#page-24" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-7.1" href="#section-7.1">7.1</a>. Write Locks and Properties</h3></span> + + While those without a write lock may not alter a property on a + resource it is still possible for the values of live properties to + change, even while locked, due to the requirements of their schemas. + Only dead properties and live properties defined as lockable are + guaranteed not to change while write locked. + +<span class="h3"><h3><a class="selflink" name="section-7.2" href="#section-7.2">7.2</a>. Avoiding Lost Updates</h3></span> + + Although the write locks provide some help in preventing lost + updates, they cannot guarantee that updates will never be lost. + Consider the following scenario: + + Two clients A and B are interested in editing the resource + 'index.html'. Client A is an HTTP client rather than a WebDAV + client, and so does not know how to perform locking. + + Client A doesn't lock the document, but does a GET, and begins + editing. + + Client B does LOCK, performs a GET and begins editing. + + Client B finishes editing, performs a PUT, then an UNLOCK. + + Client A performs a PUT, overwriting and losing all of B's changes. + + There are several reasons why the WebDAV protocol itself cannot + prevent this situation. First, it cannot force all clients to use + locking because it must be compatible with HTTP clients that do not + comprehend locking. Second, it cannot require servers to support + locking because of the variety of repository implementations, some of + which rely on reservations and merging rather than on locking. + Finally, being stateless, it cannot enforce a sequence of operations + like LOCK / GET / PUT / UNLOCK. + + WebDAV servers that support locking can reduce the likelihood that + clients will accidentally overwrite each other's changes by requiring + clients to lock resources before modifying them. Such servers would + effectively prevent HTTP 1.0 and HTTP 1.1 clients from modifying + resources. + + WebDAV clients can be good citizens by using a lock / retrieve / + write /unlock sequence of operations (at least by default) whenever + they interact with a WebDAV server that supports locking. + + + + + + +<span class="grey">Dusseault Standards Track [Page 24]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-25" id="page-25" href="#page-25" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + HTTP 1.1 clients can be good citizens, avoiding overwriting other + clients' changes, by using entity tags in If-Match headers with any + requests that would modify resources. + + Information managers may attempt to prevent overwrites by + implementing client-side procedures requiring locking before + modifying WebDAV resources. + +<span class="h3"><h3><a class="selflink" name="section-7.3" href="#section-7.3">7.3</a>. Write Locks and Unmapped URLs</h3></span> + + WebDAV provides the ability to send a LOCK request to an unmapped URL + in order to reserve the name for use. This is a simple way to avoid + the lost-update problem on the creation of a new resource (another + way is to use If-None-Match header specified in <a href="http://tools.ietf.org/html/rfc2616#section-14.26">Section 14.26 of + [RFC2616]</a>). It has the side benefit of locking the new resource + immediately for use of the creator. + + Note that the lost-update problem is not an issue for collections + because MKCOL can only be used to create a collection, not to + overwrite an existing collection. When trying to lock a collection + upon creation, clients can attempt to increase the likelihood of + getting the lock by pipelining the MKCOL and LOCK requests together + (but because this doesn't convert two separate operations into one + atomic operation, there's no guarantee this will work). + + A successful lock request to an unmapped URL MUST result in the + creation of a locked (non-collection) resource with empty content. + Subsequently, a successful PUT request (with the correct lock token) + provides the content for the resource. Note that the LOCK request + has no mechanism for the client to provide Content-Type or Content- + Language, thus the server will use defaults or empty values and rely + on the subsequent PUT request for correct values. + + A resource created with a LOCK is empty but otherwise behaves in + every way as a normal resource. It behaves the same way as a + resource created by a PUT request with an empty body (and where a + Content-Type and Content-Language was not specified), followed by a + LOCK request to the same resource. Following from this model, a + locked empty resource: + + o Can be read, deleted, moved, and copied, and in all ways behaves + as a regular non-collection resource. + + o Appears as a member of its parent collection. + + o SHOULD NOT disappear when its lock goes away (clients must + therefore be responsible for cleaning up their own mess, as with + any other operation or any non-empty resource). + + + +<span class="grey">Dusseault Standards Track [Page 25]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-26" id="page-26" href="#page-26" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + o MAY NOT have values for properties like DAV:getcontentlanguage + that haven't been specified yet by the client. + + o Can be updated (have content added) with a PUT request. + + o MUST NOT be converted into a collection. The server MUST fail a + MKCOL request (as it would with a MKCOL request to any existing + non-collection resource). + + o MUST have defined values for DAV:lockdiscovery and DAV: + supportedlock properties. + + o The response MUST indicate that a resource was created, by use of + the "201 Created" response code (a LOCK request to an existing + resource instead will result in 200 OK). The body must still + include the DAV:lockdiscovery property, as with a LOCK request to + an existing resource. + + The client is expected to update the locked empty resource shortly + after locking it, using PUT and possibly PROPPATCH. + + Alternatively and for backwards compatibility to [<a href="http://tools.ietf.org/html/rfc2518" title="" http extensions for distributed authoring webdav>RFC2518</a>], servers + MAY implement Lock-Null Resources (LNRs) instead (see definition in + <a href="#appendix-D">Appendix D</a>). Clients can easily interoperate both with servers that + support the old model LNRs and the recommended model of "locked empty + resources" by only attempting PUT after a LOCK to an unmapped URL, + not MKCOL or GET, and by not relying on specific properties of LNRs. + +<span class="h3"><h3><a class="selflink" name="section-7.4" href="#section-7.4">7.4</a>. Write Locks and Collections</h3></span> + + There are two kinds of collection write locks. A depth-0 write lock + on a collection protects the collection properties plus the internal + member URLs of that one collection, while not protecting the content + or properties of member resources (if the collection itself has any + entity bodies, those are also protected). A depth-infinity write + lock on a collection provides the same protection on that collection + and also provides write lock protection on every member resource. + + Expressed otherwise, a write lock of either kind protects any request + that would create a new resource in a write locked collection, any + request that would remove an internal member URL of a write locked + collection, and any request that would change the segment name of any + internal member. + + Thus, a collection write lock protects all the following actions: + + o DELETE a collection's direct internal member, + + + + +<span class="grey">Dusseault Standards Track [Page 26]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-27" id="page-27" href="#page-27" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + o MOVE an internal member out of the collection, + + o MOVE an internal member into the collection, + + o MOVE to rename an internal member within a collection, + + o COPY an internal member into a collection, and + + o PUT or MKCOL request that would create a new internal member. + + The collection's lock token is required in addition to the lock token + on the internal member itself, if it is locked separately. + + In addition, a depth-infinity lock affects all write operations to + all members of the locked collection. With a depth-infinity lock, + the resource identified by the root of the lock is directly locked, + and all its members are indirectly locked. + + o Any new resource added as a descendant of a depth-infinity locked + collection becomes indirectly locked. + + o Any indirectly locked resource moved out of the locked collection + into an unlocked collection is thereafter unlocked. + + o Any indirectly locked resource moved out of a locked source + collection into a depth-infinity locked target collection remains + indirectly locked but is now protected by the lock on the target + collection (the target collection's lock token will thereafter be + required to make further changes). + + If a depth-infinity write LOCK request is issued to a collection + containing member URLs identifying resources that are currently + locked in a manner that conflicts with the new lock (see <a href="#section-6.1">Section 6.1</a>, + point 3), the request MUST fail with a 423 (Locked) status code, and + the response SHOULD contain the 'no-conflicting-lock' precondition. + + If a lock request causes the URL of a resource to be added as an + internal member URL of a depth-infinity locked collection, then the + new resource MUST be automatically protected by the lock. For + example, if the collection /a/b/ is write locked and the resource /c + is moved to /a/b/c, then resource /a/b/c will be added to the write + lock. + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 27]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-28" id="page-28" href="#page-28" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-7.5" href="#section-7.5">7.5</a>. Write Locks and the If Request Header</h3></span> + + A user agent has to demonstrate knowledge of a lock when requesting + an operation on a locked resource. Otherwise, the following scenario + might occur. In the scenario, program A, run by User A, takes out a + write lock on a resource. Program B, also run by User A, has no + knowledge of the lock taken out by program A, yet performs a PUT to + the locked resource. In this scenario, the PUT succeeds because + locks are associated with a principal, not a program, and thus + program B, because it is acting with principal A's credential, is + allowed to perform the PUT. However, had program B known about the + lock, it would not have overwritten the resource, preferring instead + to present a dialog box describing the conflict to the user. Due to + this scenario, a mechanism is needed to prevent different programs + from accidentally ignoring locks taken out by other programs with the + same authorization. + + In order to prevent these collisions, a lock token MUST be submitted + by an authorized principal for all locked resources that a method may + change or the method MUST fail. A lock token is submitted when it + appears in an If header. For example, if a resource is to be moved + and both the source and destination are locked, then two lock tokens + must be submitted in the If header, one for the source and the other + for the destination. + +<span class="h4"><h4><a class="selflink" name="section-7.5.1" href="#section-7.5.1">7.5.1</a>. Example - Write Lock and COPY</h4></span> + + >>Request + + COPY /~fielding/index.html HTTP/1.1 + Host: www.example.com + Destination: http://www.example.com/users/f/fielding/index.html + If: <http://www.example.com/users/f/fielding/index.html> + (<urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6>) + + >>Response + + HTTP/1.1 204 No Content + + In this example, even though both the source and destination are + locked, only one lock token must be submitted (the one for the lock + on the destination). This is because the source resource is not + modified by a COPY, and hence unaffected by the write lock. In this + example, user agent authentication has previously occurred via a + mechanism outside the scope of the HTTP protocol, in the underlying + transport layer. + + + + + +<span class="grey">Dusseault Standards Track [Page 28]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-29" id="page-29" href="#page-29" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-7.5.2" href="#section-7.5.2">7.5.2</a>. Example - Deleting a Member of a Locked Collection</h4></span> + + Consider a collection "/locked" with an exclusive, depth-infinity + write lock, and an attempt to delete an internal member "/locked/ + member": + + >>Request + + DELETE /locked/member HTTP/1.1 + Host: example.com + + >>Response + + HTTP/1.1 423 Locked + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:error xmlns:D="DAV:"> + <D:lock-token-submitted> + <D:href>/locked/</D:href> + </D:lock-token-submitted> + </D:error> + + Thus, the client would need to submit the lock token with the request + to make it succeed. To do that, various forms of the If header (see + <a href="#section-10.4">Section 10.4</a>) could be used. + + "No-Tag-List" format: + + If: (<urn:uuid:150852e2-3847-42d5-8cbe-0f4f296f26cf>) + + "Tagged-List" format, for "http://example.com/locked/": + + If: <http://example.com/locked/> + (<urn:uuid:150852e2-3847-42d5-8cbe-0f4f296f26cf>) + + "Tagged-List" format, for "http://example.com/locked/member": + + If: <http://example.com/locked/member> + (<urn:uuid:150852e2-3847-42d5-8cbe-0f4f296f26cf>) + + Note that, for the purpose of submitting the lock token, the actual + form doesn't matter; what's relevant is that the lock token appears + in the If header, and that the If header itself evaluates to true. + + + + + + +<span class="grey">Dusseault Standards Track [Page 29]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-30" id="page-30" href="#page-30" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-7.6" href="#section-7.6">7.6</a>. Write Locks and COPY/MOVE</h3></span> + + A COPY method invocation MUST NOT duplicate any write locks active on + the source. However, as previously noted, if the COPY copies the + resource into a collection that is locked with a depth-infinity lock, + then the resource will be added to the lock. + + A successful MOVE request on a write locked resource MUST NOT move + the write lock with the resource. However, if there is an existing + lock at the destination, the server MUST add the moved resource to + the destination lock scope. For example, if the MOVE makes the + resource a child of a collection that has a depth-infinity lock, then + the resource will be added to that collection's lock. Additionally, + if a resource with a depth-infinity lock is moved to a destination + that is within the scope of the same lock (e.g., within the URL + namespace tree covered by the lock), the moved resource will again be + added to the lock. In both these examples, as specified in + <a href="#section-7.5">Section 7.5</a>, an If header must be submitted containing a lock token + for both the source and destination. + +<span class="h3"><h3><a class="selflink" name="section-7.7" href="#section-7.7">7.7</a>. Refreshing Write Locks</h3></span> + + A client MUST NOT submit the same write lock request twice. Note + that a client is always aware it is resubmitting the same lock + request because it must include the lock token in the If header in + order to make the request for a resource that is already locked. + + However, a client may submit a LOCK request with an If header but + without a body. A server receiving a LOCK request with no body MUST + NOT create a new lock -- this form of the LOCK request is only to be + used to "refresh" an existing lock (meaning, at minimum, that any + timers associated with the lock MUST be reset). + + Clients may submit Timeout headers of arbitrary value with their lock + refresh requests. Servers, as always, may ignore Timeout headers + submitted by the client, and a server MAY refresh a lock with a + timeout period that is different than the previous timeout period + used for the lock, provided it advertises the new value in the LOCK + refresh response. + + If an error is received in response to a refresh LOCK request, the + client MUST NOT assume that the lock was refreshed. + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 30]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-31" id="page-31" href="#page-31" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="section-8" href="#section-8">8</a>. General Request and Response Handling</h2></span> + +<span class="h3"><h3><a class="selflink" name="section-8.1" href="#section-8.1">8.1</a>. Precedence in Error Handling</h3></span> + + Servers MUST return authorization errors in preference to other + errors. This avoids leaking information about protected resources + (e.g., a client that finds that a hidden resource exists by seeing a + 423 Locked response to an anonymous request to the resource). + +<span class="h3"><h3><a class="selflink" name="section-8.2" href="#section-8.2">8.2</a>. Use of XML</h3></span> + + In HTTP/1.1, method parameter information was exclusively encoded in + HTTP headers. Unlike HTTP/1.1, WebDAV encodes method parameter + information either in an XML ([<a href="#ref-REC-XML" title="" extensible markup language edition>REC-XML</a>]) request entity body, or in + an HTTP header. The use of XML to encode method parameters was + motivated by the ability to add extra XML elements to existing + structures, providing extensibility; and by XML's ability to encode + information in ISO 10646 character sets, providing + internationalization support. + + In addition to encoding method parameters, XML is used in WebDAV to + encode the responses from methods, providing the extensibility and + internationalization advantages of XML for method output, as well as + input. + + When XML is used for a request or response body, the Content-Type + type SHOULD be application/xml. Implementations MUST accept both + text/xml and application/xml in request and response bodies. Use of + text/xml is deprecated. + + All DAV-compliant clients and resources MUST use XML parsers that are + compliant with [<a href="#ref-REC-XML" title="" extensible markup language edition>REC-XML</a>] and [<a href="#ref-REC-XML-NAMES" title="" namespaces in xml edition>REC-XML-NAMES</a>]. All XML used in either + requests or responses MUST be, at minimum, well formed and use + namespaces correctly. If a server receives XML that is not well- + formed, then the server MUST reject the entire request with a 400 + (Bad Request). If a client receives XML that is not well-formed in a + response, then the client MUST NOT assume anything about the outcome + of the executed method and SHOULD treat the server as malfunctioning. + + Note that processing XML submitted by an untrusted source may cause + risks connected to privacy, security, and service quality (see + <a href="#section-20">Section 20</a>). Servers MAY reject questionable requests (even though + they consist of well-formed XML), for instance, with a 400 (Bad + Request) status code and an optional response body explaining the + problem. + + + + + + +<span class="grey">Dusseault Standards Track [Page 31]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-32" id="page-32" href="#page-32" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-8.3" href="#section-8.3">8.3</a>. URL Handling</h3></span> + + URLs appear in many places in requests and responses. + Interoperability experience with [<a href="http://tools.ietf.org/html/rfc2518" title="" http extensions for distributed authoring webdav>RFC2518</a>] showed that many clients + parsing Multi-Status responses did not fully implement the full + Reference Resolution defined in <a href="http://tools.ietf.org/html/rfc3986#section-5">Section 5 of [RFC3986]</a>. Thus, + servers in particular need to be careful in handling URLs in + responses, to ensure that clients have enough context to be able to + interpret all the URLs. The rules in this section apply not only to + resource URLs in the 'href' element in Multi-Status responses, but + also to the Destination and If header resource URLs. + + The sender has a choice between two approaches: using a relative + reference, which is resolved against the Request-URI, or a full URI. + A server MUST ensure that every 'href' value within a Multi-Status + response uses the same format. + + WebDAV only uses one form of relative reference in its extensions, + the absolute path. + + Simple-ref = absolute-URI | ( path-absolute [ "?" query ] ) + + The absolute-URI, path-absolute and query productions are defined in + Sections <a href="#section-4.3">4.3</a>, <a href="#section-3.3">3.3</a>, and <a href="#section-3.4">3.4</a> of [<a href="http://tools.ietf.org/html/rfc3986" title="" uniform resource identifier generic syntax>RFC3986</a>]. + + Within Simple-ref productions, senders MUST NOT: + + o use dot-segments ("." or ".."), or + + o have prefixes that do not match the Request-URI (using the + comparison rules defined in <a href="http://tools.ietf.org/html/rfc2616#section-3.2.3">Section 3.2.3 of [RFC2616]</a>). + + Identifiers for collections SHOULD end in a '/' character. + +<span class="h4"><h4><a class="selflink" name="section-8.3.1" href="#section-8.3.1">8.3.1</a>. Example - Correct URL Handling</h4></span> + + Consider the collection http://example.com/sample/ with the internal + member URL http://example.com/sample/a%20test and the PROPFIND + request below: + + >>Request: + + PROPFIND /sample/ HTTP/1.1 + Host: example.com + Depth: 1 + + + + + + +<span class="grey">Dusseault Standards Track [Page 32]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-33" id="page-33" href="#page-33" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + In this case, the server should return two 'href' elements containing + either + + o 'http://example.com/sample/' and + 'http://example.com/sample/a%20test', or + + o '/sample/' and '/sample/a%20test' + + Note that even though the server may be storing the member resource + internally as 'a test', it has to be percent-encoded when used inside + a URI reference (see <a href="http://tools.ietf.org/html/rfc3986#section-2.1">Section 2.1 of [RFC3986]</a>). Also note that a + legal URI may still contain characters that need to be escaped within + XML character data, such as the ampersand character. + +<span class="h3"><h3><a class="selflink" name="section-8.4" href="#section-8.4">8.4</a>. Required Bodies in Requests</h3></span> + + Some of these new methods do not define bodies. Servers MUST examine + all requests for a body, even when a body was not expected. In cases + where a request body is present but would be ignored by a server, the + server MUST reject the request with 415 (Unsupported Media Type). + This informs the client (which may have been attempting to use an + extension) that the body could not be processed as the client + intended. + +<span class="h3"><h3><a class="selflink" name="section-8.5" href="#section-8.5">8.5</a>. HTTP Headers for Use in WebDAV</h3></span> + + HTTP defines many headers that can be used in WebDAV requests and + responses. Not all of these are appropriate in all situations and + some interactions may be undefined. Note that HTTP 1.1 requires the + Date header in all responses if possible (see <a href="#section-14.18">Section 14.18</a>, + [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>]). + + The server MUST do authorization checks before checking any HTTP + conditional header. + +<span class="h3"><h3><a class="selflink" name="section-8.6" href="#section-8.6">8.6</a>. ETag</h3></span> + + HTTP 1.1 recommends the use of ETags rather than modification dates, + for cache control, and there are even stronger reasons to prefer + ETags for authoring. Correct use of ETags is even more important in + a distributed authoring environment, because ETags are necessary + along with locks to avoid the lost-update problem. A client might + fail to renew a lock, for example, when the lock times out and the + client is accidentally offline or in the middle of a long upload. + When a client fails to renew the lock, it's quite possible the + resource can still be relocked and the user can go on editing, as + long as no changes were made in the meantime. ETags are required for + the client to be able to distinguish this case. Otherwise, the + + + +<span class="grey">Dusseault Standards Track [Page 33]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-34" id="page-34" href="#page-34" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + client is forced to ask the user whether to overwrite the resource on + the server without even being able to tell the user if it has + changed. Timestamps do not solve this problem nearly as well as + ETags. + + Strong ETags are much more useful for authoring use cases than weak + ETags (see <a href="http://tools.ietf.org/html/rfc2616#section-13.3.3">Section 13.3.3 of [RFC2616]</a>). Semantic equivalence can be + a useful concept but that depends on the document type and the + application type, and interoperability might require some agreement + or standard outside the scope of this specification and HTTP. Note + also that weak ETags have certain restrictions in HTTP, e.g., these + cannot be used in If-Match headers. + + Note that the meaning of an ETag in a PUT response is not clearly + defined either in this document or in <a href="http://tools.ietf.org/html/rfc2616">RFC 2616</a> (i.e., whether the + ETag means that the resource is octet-for-octet equivalent to the + body of the PUT request, or whether the server could have made minor + changes in the formatting or content of the document upon storage). + This is an HTTP issue, not purely a WebDAV issue. + + Because clients may be forced to prompt users or throw away changed + content if the ETag changes, a WebDAV server SHOULD NOT change the + ETag (or the Last-Modified time) for a resource that has an unchanged + body and location. The ETag represents the state of the body or + contents of the resource. There is no similar way to tell if + properties have changed. + +<span class="h3"><h3><a class="selflink" name="section-8.7" href="#section-8.7">8.7</a>. Including Error Response Bodies</h3></span> + + HTTP and WebDAV did not use the bodies of most error responses for + machine-parsable information until the specification for Versioning + Extensions to WebDAV introduced a mechanism to include more specific + information in the body of an error response (<a href="http://tools.ietf.org/html/rfc3253#section-1.6">Section 1.6 of + [RFC3253]</a>). The error body mechanism is appropriate to use with any + error response that may take a body but does not already have a body + defined. The mechanism is particularly appropriate when a status + code can mean many things (for example, 400 Bad Request can mean + required headers are missing, headers are incorrectly formatted, or + much more). This error body mechanism is covered in <a href="#section-16">Section 16</a>. + +<span class="h3"><h3><a class="selflink" name="section-8.8" href="#section-8.8">8.8</a>. Impact of Namespace Operations on Cache Validators</h3></span> + + Note that the HTTP response headers "Etag" and "Last-Modified" (see + [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>], Sections <a href="#section-14.19">14.19</a> and <a href="#section-14.29">14.29</a>) are defined per URL (not per + resource), and are used by clients for caching. Therefore servers + must ensure that executing any operation that affects the URL + namespace (such as COPY, MOVE, DELETE, PUT, or MKCOL) does preserve + their semantics, in particular: + + + +<span class="grey">Dusseault Standards Track [Page 34]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-35" id="page-35" href="#page-35" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + o For any given URL, the "Last-Modified" value MUST increment every + time the representation returned upon GET changes (within the + limits of timestamp resolution). + + o For any given URL, an "ETag" value MUST NOT be reused for + different representations returned by GET. + + In practice this means that servers + + o might have to increment "Last-Modified" timestamps for every + resource inside the destination namespace of a namespace operation + unless it can do so more selectively, and + + o similarly, might have to re-assign "ETag" values for these + resources (unless the server allocates entity tags in a way so + that they are unique across the whole URL namespace managed by the + server). + + Note that these considerations also apply to specific use cases, such + as using PUT to create a new resource at a URL that has been mapped + before, but has been deleted since then. + + Finally, WebDAV properties (such as DAV:getetag and DAV: + getlastmodified) that inherit their semantics from HTTP headers must + behave accordingly. + +<span class="h2"><h2><a class="selflink" name="section-9" href="#section-9">9</a>. HTTP Methods for Distributed Authoring</h2></span> + +<span class="h3"><h3><a class="selflink" name="section-9.1" href="#section-9.1">9.1</a>. PROPFIND Method</h3></span> + + The PROPFIND method retrieves properties defined on the resource + identified by the Request-URI, if the resource does not have any + internal members, or on the resource identified by the Request-URI + and potentially its member resources, if the resource is a collection + that has internal member URLs. All DAV-compliant resources MUST + support the PROPFIND method and the propfind XML element + (<a href="#section-14.20">Section 14.20</a>) along with all XML elements defined for use with that + element. + + A client MUST submit a Depth header with a value of "0", "1", or + "infinity" with a PROPFIND request. Servers MUST support "0" and "1" + depth requests on WebDAV-compliant resources and SHOULD support + "infinity" requests. In practice, support for infinite-depth + requests MAY be disabled, due to the performance and security + concerns associated with this behavior. Servers SHOULD treat a + request without a Depth header as if a "Depth: infinity" header was + included. + + + + +<span class="grey">Dusseault Standards Track [Page 35]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-36" id="page-36" href="#page-36" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + A client may submit a 'propfind' XML element in the body of the + request method describing what information is being requested. It is + possible to: + + o Request particular property values, by naming the properties + desired within the 'prop' element (the ordering of properties in + here MAY be ignored by the server), + + o Request property values for those properties defined in this + specification (at a minimum) plus dead properties, by using the + 'allprop' element (the 'include' element can be used with + 'allprop' to instruct the server to also include additional live + properties that may not have been returned otherwise), + + o Request a list of names of all the properties defined on the + resource, by using the 'propname' element. + + A client may choose not to submit a request body. An empty PROPFIND + request body MUST be treated as if it were an 'allprop' request. + + Note that 'allprop' does not return values for all live properties. + WebDAV servers increasingly have expensively-calculated or lengthy + properties (see [<a href="http://tools.ietf.org/html/rfc3253" title="" versioning extensions to webdav distributed authoring and>RFC3253</a>] and [<a href="http://tools.ietf.org/html/rfc3744" title="" web distributed authoring and versioning access control protocol>RFC3744</a>]) and do not return all + properties already. Instead, WebDAV clients can use propname + requests to discover what live properties exist, and request named + properties when retrieving values. For a live property defined + elsewhere, that definition can specify whether or not that live + property would be returned in 'allprop' requests. + + All servers MUST support returning a response of content type text/ + xml or application/xml that contains a multistatus XML element that + describes the results of the attempts to retrieve the various + properties. + + If there is an error retrieving a property, then a proper error + result MUST be included in the response. A request to retrieve the + value of a property that does not exist is an error and MUST be noted + with a 'response' XML element that contains a 404 (Not Found) status + value. + + Consequently, the 'multistatus' XML element for a collection resource + MUST include a 'response' XML element for each member URL of the + collection, to whatever depth was requested. It SHOULD NOT include + any 'response' elements for resources that are not WebDAV-compliant. + Each 'response' element MUST contain an 'href' element that contains + the URL of the resource on which the properties in the prop XML + element are defined. Results for a PROPFIND on a collection resource + are returned as a flat list whose order of entries is not + + + +<span class="grey">Dusseault Standards Track [Page 36]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-37" id="page-37" href="#page-37" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + significant. Note that a resource may have only one value for a + property of a given name, so the property may only show up once in + PROPFIND responses. + + Properties may be subject to access control. In the case of + 'allprop' and 'propname' requests, if a principal does not have the + right to know whether a particular property exists, then the property + MAY be silently excluded from the response. + + Some PROPFIND results MAY be cached, with care, as there is no cache + validation mechanism for most properties. This method is both safe + and idempotent (see <a href="http://tools.ietf.org/html/rfc2616#section-9.1">Section 9.1 of [RFC2616]</a>). + +<span class="h4"><h4><a class="selflink" name="section-9.1.1" href="#section-9.1.1">9.1.1</a>. PROPFIND Status Codes</h4></span> + + This section, as with similar sections for other methods, provides + some guidance on error codes and preconditions or postconditions + (defined in <a href="#section-16">Section 16</a>) that might be particularly useful with + PROPFIND. + + 403 Forbidden - A server MAY reject PROPFIND requests on collections + with depth header of "Infinity", in which case it SHOULD use this + error with the precondition code 'propfind-finite-depth' inside the + error body. + +<span class="h4"><h4><a class="selflink" name="section-9.1.2" href="#section-9.1.2">9.1.2</a>. Status Codes for Use in 'propstat' Element</h4></span> + + In PROPFIND responses, information about individual properties is + returned inside 'propstat' elements (see <a href="#section-14.22">Section 14.22</a>), each + containing an individual 'status' element containing information + about the properties appearing in it. The list below summarizes the + most common status codes used inside 'propstat'; however, clients + should be prepared to handle other 2/3/4/5xx series status codes as + well. + + 200 OK - A property exists and/or its value is successfully returned. + + 401 Unauthorized - The property cannot be viewed without appropriate + authorization. + + 403 Forbidden - The property cannot be viewed regardless of + authentication. + + 404 Not Found - The property does not exist. + + + + + + + +<span class="grey">Dusseault Standards Track [Page 37]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-38" id="page-38" href="#page-38" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-9.1.3" href="#section-9.1.3">9.1.3</a>. Example - Retrieving Named Properties</h4></span> + + >>Request + + PROPFIND /file HTTP/1.1 + Host: www.example.com + Content-type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:propfind xmlns:D="DAV:"> + <D:prop xmlns:R="http://ns.example.com/boxschema/"> + <R:bigbox/> + <R:author/> + <R:DingALing/> + <R:Random/> + </D:prop> + </D:propfind> + + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:multistatus xmlns:D="DAV:"> + <D:response xmlns:R="http://ns.example.com/boxschema/"> + <D:href>http://www.example.com/file</D:href> + <D:propstat> + <D:prop> + <R:bigbox> + <R:BoxType>Box type A</R:BoxType> + </R:bigbox> + <R:author> + <R:Name>J.J. Johnson</R:Name> + </R:author> + </D:prop> + <D:status>HTTP/1.1 200 OK</D:status> + </D:propstat> + <D:propstat> + <D:prop><R:DingALing/><R:Random/></D:prop> + <D:status>HTTP/1.1 403 Forbidden</D:status> + <D:responsedescription> The user does not have access to the + DingALing property. + </D:responsedescription> + </D:propstat> + + + +<span class="grey">Dusseault Standards Track [Page 38]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-39" id="page-39" href="#page-39" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + </D:response> + <D:responsedescription> There has been an access violation error. + </D:responsedescription> + </D:multistatus> + + + In this example, PROPFIND is executed on a non-collection resource + http://www.example.com/file. The propfind XML element specifies the + name of four properties whose values are being requested. In this + case, only two properties were returned, since the principal issuing + the request did not have sufficient access rights to see the third + and fourth properties. + +<span class="h4"><h4><a class="selflink" name="section-9.1.4" href="#section-9.1.4">9.1.4</a>. Example - Using 'propname' to Retrieve All Property Names</h4></span> + + >>Request + + PROPFIND /container/ HTTP/1.1 + Host: www.example.com + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <propfind xmlns="DAV:"> + <propname/> + </propfind> + + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <multistatus xmlns="DAV:"> + <response> + <href>http://www.example.com/container/</href> + <propstat> + <prop xmlns:R="http://ns.example.com/boxschema/"> + <R:bigbox/> + <R:author/> + <creationdate/> + <displayname/> + <resourcetype/> + <supportedlock/> + </prop> + <status>HTTP/1.1 200 OK</status> + + + +<span class="grey">Dusseault Standards Track [Page 39]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-40" id="page-40" href="#page-40" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + </propstat> + </response> + <response> + <href>http://www.example.com/container/front.html</href> + <propstat> + <prop xmlns:R="http://ns.example.com/boxschema/"> + <R:bigbox/> + <creationdate/> + <displayname/> + <getcontentlength/> + <getcontenttype/> + <getetag/> + <getlastmodified/> + <resourcetype/> + <supportedlock/> + </prop> + <status>HTTP/1.1 200 OK</status> + </propstat> + </response> + </multistatus> + + In this example, PROPFIND is invoked on the collection resource + http://www.example.com/container/, with a propfind XML element + containing the propname XML element, meaning the name of all + properties should be returned. Since no Depth header is present, it + assumes its default value of "infinity", meaning the name of the + properties on the collection and all its descendants should be + returned. + + Consistent with the previous example, resource + http://www.example.com/container/ has six properties defined on it: + bigbox and author in the "http://ns.example.com/boxschema/" + namespace, and creationdate, displayname, resourcetype, and + supportedlock in the "DAV:" namespace. + + The resource http://www.example.com/container/index.html, a member of + the "container" collection, has nine properties defined on it, bigbox + in the "http://ns.example.com/boxschema/" namespace and creationdate, + displayname, getcontentlength, getcontenttype, getetag, + getlastmodified, resourcetype, and supportedlock in the "DAV:" + namespace. + + This example also demonstrates the use of XML namespace scoping and + the default namespace. Since the "xmlns" attribute does not contain + a prefix, the namespace applies by default to all enclosed elements. + Hence, all elements that do not explicitly state the namespace to + which they belong are members of the "DAV:" namespace. + + + + +<span class="grey">Dusseault Standards Track [Page 40]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-41" id="page-41" href="#page-41" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-9.1.5" href="#section-9.1.5">9.1.5</a>. Example - Using So-called 'allprop'</h4></span> + + Note that 'allprop', despite its name, which remains for backward- + compatibility, does not return every property, but only dead + properties and the live properties defined in this specification. + + >>Request + + PROPFIND /container/ HTTP/1.1 + Host: www.example.com + Depth: 1 + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:propfind xmlns:D="DAV:"> + <D:allprop/> + </D:propfind> + + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:multistatus xmlns:D="DAV:"> + <D:response> + <D:href>/container/</D:href> + <D:propstat> + <D:prop xmlns:R="http://ns.example.com/boxschema/"> + <R:bigbox><R:BoxType>Box type A</R:BoxType></R:bigbox> + <R:author><R:Name>Hadrian</R:Name></R:author> + <D:creationdate>1997-12-01T17:42:21-08:00</D:creationdate> + <D:displayname>Example collection</D:displayname> + <D:resourcetype><D:collection/></D:resourcetype> + <D:supportedlock> + <D:lockentry> + <D:lockscope><D:exclusive/></D:lockscope> + <D:locktype><D:write/></D:locktype> + </D:lockentry> + <D:lockentry> + <D:lockscope><D:shared/></D:lockscope> + <D:locktype><D:write/></D:locktype> + </D:lockentry> + </D:supportedlock> + </D:prop> + + + +<span class="grey">Dusseault Standards Track [Page 41]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-42" id="page-42" href="#page-42" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + <D:status>HTTP/1.1 200 OK</D:status> + </D:propstat> + </D:response> + <D:response> + <D:href>/container/front.html</D:href> + <D:propstat> + <D:prop xmlns:R="http://ns.example.com/boxschema/"> + <R:bigbox><R:BoxType>Box type B</R:BoxType> + </R:bigbox> + <D:creationdate>1997-12-01T18:27:21-08:00</D:creationdate> + <D:displayname>Example HTML resource</D:displayname> + <D:getcontentlength>4525</D:getcontentlength> + <D:getcontenttype>text/html</D:getcontenttype> + <D:getetag>"zzyzx"</D:getetag> + <D:getlastmodified + >Mon, 12 Jan 1998 09:25:56 GMT</D:getlastmodified> + <D:resourcetype/> + <D:supportedlock> + <D:lockentry> + <D:lockscope><D:exclusive/></D:lockscope> + <D:locktype><D:write/></D:locktype> + </D:lockentry> + <D:lockentry> + <D:lockscope><D:shared/></D:lockscope> + <D:locktype><D:write/></D:locktype> + </D:lockentry> + </D:supportedlock> + </D:prop> + <D:status>HTTP/1.1 200 OK</D:status> + </D:propstat> + </D:response> + </D:multistatus> + + In this example, PROPFIND was invoked on the resource + http://www.example.com/container/ with a Depth header of 1, meaning + the request applies to the resource and its children, and a propfind + XML element containing the allprop XML element, meaning the request + should return the name and value of all the dead properties defined + on the resources, plus the name and value of all the properties + defined in this specification. This example illustrates the use of + relative references in the 'href' elements of the response. + + The resource http://www.example.com/container/ has six properties + defined on it: 'bigbox' and 'author in the + "http://ns.example.com/boxschema/" namespace, DAV:creationdate, DAV: + displayname, DAV:resourcetype, and DAV:supportedlock. + + + + + +<span class="grey">Dusseault Standards Track [Page 42]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-43" id="page-43" href="#page-43" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + The last four properties are WebDAV-specific, defined in <a href="#section-15">Section 15</a>. + Since GET is not supported on this resource, the get* properties + (e.g., DAV:getcontentlength) are not defined on this resource. The + WebDAV-specific properties assert that "container" was created on + December 1, 1997, at 5:42:21PM, in a time zone 8 hours west of GMT + (DAV:creationdate), has a name of "Example collection" (DAV: + displayname), a collection resource type (DAV:resourcetype), and + supports exclusive write and shared write locks (DAV:supportedlock). + + The resource http://www.example.com/container/front.html has nine + properties defined on it: + + 'bigbox' in the "http://ns.example.com/boxschema/" namespace (another + instance of the "bigbox" property type), DAV:creationdate, DAV: + displayname, DAV:getcontentlength, DAV:getcontenttype, DAV:getetag, + DAV:getlastmodified, DAV:resourcetype, and DAV:supportedlock. + + The DAV-specific properties assert that "front.html" was created on + December 1, 1997, at 6:27:21PM, in a time zone 8 hours west of GMT + (DAV:creationdate), has a name of "Example HTML resource" (DAV: + displayname), a content length of 4525 bytes (DAV:getcontentlength), + a MIME type of "text/html" (DAV:getcontenttype), an entity tag of + "zzyzx" (DAV:getetag), was last modified on Monday, January 12, 1998, + at 09:25:56 GMT (DAV:getlastmodified), has an empty resource type, + meaning that it is not a collection (DAV:resourcetype), and supports + both exclusive write and shared write locks (DAV:supportedlock). + +<span class="h4"><h4><a class="selflink" name="section-9.1.6" href="#section-9.1.6">9.1.6</a>. Example - Using 'allprop' with 'include'</h4></span> + + >>Request + + PROPFIND /mycol/ HTTP/1.1 + Host: www.example.com + Depth: 1 + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:propfind xmlns:D="DAV:"> + <D:allprop/> + <D:include> + <D:supported-live-property-set/> + <D:supported-report-set/> + </D:include> + </D:propfind> + + + + + + +<span class="grey">Dusseault Standards Track [Page 43]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-44" id="page-44" href="#page-44" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + In this example, PROPFIND is executed on the resource + http://www.example.com/mycol/ and its internal member resources. The + client requests the values of all live properties defined in this + specification, plus all dead properties, plus two more live + properties defined in [<a href="http://tools.ietf.org/html/rfc3253" title="" versioning extensions to webdav distributed authoring and>RFC3253</a>]. The response is not shown. + +<span class="h3"><h3><a class="selflink" name="section-9.2" href="#section-9.2">9.2</a>. PROPPATCH Method</h3></span> + + The PROPPATCH method processes instructions specified in the request + body to set and/or remove properties defined on the resource + identified by the Request-URI. + + All DAV-compliant resources MUST support the PROPPATCH method and + MUST process instructions that are specified using the + propertyupdate, set, and remove XML elements. Execution of the + directives in this method is, of course, subject to access control + constraints. DAV-compliant resources SHOULD support the setting of + arbitrary dead properties. + + The request message body of a PROPPATCH method MUST contain the + propertyupdate XML element. + + Servers MUST process PROPPATCH instructions in document order (an + exception to the normal rule that ordering is irrelevant). + Instructions MUST either all be executed or none executed. Thus, if + any error occurs during processing, all executed instructions MUST be + undone and a proper error result returned. Instruction processing + details can be found in the definition of the set and remove + instructions in Sections <a href="#section-14.23">14.23</a> and <a href="#section-14.26">14.26</a>. + + If a server attempts to make any of the property changes in a + PROPPATCH request (i.e., the request is not rejected for high-level + errors before processing the body), the response MUST be a Multi- + Status response as described in <a href="#section-9.2.1">Section 9.2.1</a>. + + This method is idempotent, but not safe (see <a href="http://tools.ietf.org/html/rfc2616#section-9.1">Section 9.1 of + [RFC2616]</a>). Responses to this method MUST NOT be cached. + +<span class="h4"><h4><a class="selflink" name="section-9.2.1" href="#section-9.2.1">9.2.1</a>. Status Codes for Use in 'propstat' Element</h4></span> + + In PROPPATCH responses, information about individual properties is + returned inside 'propstat' elements (see <a href="#section-14.22">Section 14.22</a>), each + containing an individual 'status' element containing information + about the properties appearing in it. The list below summarizes the + most common status codes used inside 'propstat'; however, clients + should be prepared to handle other 2/3/4/5xx series status codes as + well. + + + + +<span class="grey">Dusseault Standards Track [Page 44]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-45" id="page-45" href="#page-45" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + 200 (OK) - The property set or change succeeded. Note that if this + appears for one property, it appears for every property in the + response, due to the atomicity of PROPPATCH. + + 403 (Forbidden) - The client, for reasons the server chooses not to + specify, cannot alter one of the properties. + + 403 (Forbidden): The client has attempted to set a protected + property, such as DAV:getetag. If returning this error, the server + SHOULD use the precondition code 'cannot-modify-protected-property' + inside the response body. + + 409 (Conflict) - The client has provided a value whose semantics are + not appropriate for the property. + + 424 (Failed Dependency) - The property change could not be made + because of another property change that failed. + + 507 (Insufficient Storage) - The server did not have sufficient space + to record the property. + +<span class="h4"><h4><a class="selflink" name="section-9.2.2" href="#section-9.2.2">9.2.2</a>. Example - PROPPATCH</h4></span> + + >>Request + + PROPPATCH /bar.html HTTP/1.1 + Host: www.example.com + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:propertyupdate xmlns:D="DAV:" + xmlns:Z="http://ns.example.com/standards/z39.50/"> + <D:set> + <D:prop> + <Z:Authors> + <Z:Author>Jim Whitehead</Z:Author> + <Z:Author>Roy Fielding</Z:Author> + </Z:Authors> + </D:prop> + </D:set> + <D:remove> + <D:prop><Z:Copyright-Owner/></D:prop> + </D:remove> + </D:propertyupdate> + + + + + + +<span class="grey">Dusseault Standards Track [Page 45]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-46" id="page-46" href="#page-46" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:multistatus xmlns:D="DAV:" + xmlns:Z="http://ns.example.com/standards/z39.50/"> + <D:response> + <D:href>http://www.example.com/bar.html</D:href> + <D:propstat> + <D:prop><Z:Authors/></D:prop> + <D:status>HTTP/1.1 424 Failed Dependency</D:status> + </D:propstat> + <D:propstat> + <D:prop><Z:Copyright-Owner/></D:prop> + <D:status>HTTP/1.1 409 Conflict</D:status> + </D:propstat> + <D:responsedescription> Copyright Owner cannot be deleted or + altered.</D:responsedescription> + </D:response> + </D:multistatus> + + In this example, the client requests the server to set the value of + the "Authors" property in the + "http://ns.example.com/standards/z39.50/" namespace, and to remove + the property "Copyright-Owner" in the same namespace. Since the + Copyright-Owner property could not be removed, no property + modifications occur. The 424 (Failed Dependency) status code for the + Authors property indicates this action would have succeeded if it + were not for the conflict with removing the Copyright-Owner property. + +<span class="h3"><h3><a class="selflink" name="section-9.3" href="#section-9.3">9.3</a>. MKCOL Method</h3></span> + + MKCOL creates a new collection resource at the location specified by + the Request-URI. If the Request-URI is already mapped to a resource, + then the MKCOL MUST fail. During MKCOL processing, a server MUST + make the Request-URI an internal member of its parent collection, + unless the Request-URI is "/". If no such ancestor exists, the + method MUST fail. When the MKCOL operation creates a new collection + resource, all ancestors MUST already exist, or the method MUST fail + with a 409 (Conflict) status code. For example, if a request to + create collection /a/b/c/d/ is made, and /a/b/c/ does not exist, the + request must fail. + + When MKCOL is invoked without a request body, the newly created + collection SHOULD have no members. + + + +<span class="grey">Dusseault Standards Track [Page 46]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-47" id="page-47" href="#page-47" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + A MKCOL request message may contain a message body. The precise + behavior of a MKCOL request when the body is present is undefined, + but limited to creating collections, members of a collection, bodies + of members, and properties on the collections or members. If the + server receives a MKCOL request entity type it does not support or + understand, it MUST respond with a 415 (Unsupported Media Type) + status code. If the server decides to reject the request based on + the presence of an entity or the type of an entity, it should use the + 415 (Unsupported Media Type) status code. + + This method is idempotent, but not safe (see <a href="http://tools.ietf.org/html/rfc2616#section-9.1">Section 9.1 of + [RFC2616]</a>). Responses to this method MUST NOT be cached. + +<span class="h4"><h4><a class="selflink" name="section-9.3.1" href="#section-9.3.1">9.3.1</a>. MKCOL Status Codes</h4></span> + + In addition to the general status codes possible, the following + status codes have specific applicability to MKCOL: + + 201 (Created) - The collection was created. + + 403 (Forbidden) - This indicates at least one of two conditions: 1) + the server does not allow the creation of collections at the given + location in its URL namespace, or 2) the parent collection of the + Request-URI exists but cannot accept members. + + 405 (Method Not Allowed) - MKCOL can only be executed on an unmapped + URL. + + 409 (Conflict) - A collection cannot be made at the Request-URI until + one or more intermediate collections have been created. The server + MUST NOT create those intermediate collections automatically. + + 415 (Unsupported Media Type) - The server does not support the + request body type (although bodies are legal on MKCOL requests, since + this specification doesn't define any, the server is likely not to + support any given body type). + + 507 (Insufficient Storage) - The resource does not have sufficient + space to record the state of the resource after the execution of this + method. + +<span class="h4"><h4><a class="selflink" name="section-9.3.2" href="#section-9.3.2">9.3.2</a>. Example - MKCOL</h4></span> + + This example creates a collection called /webdisc/xfiles/ on the + server www.example.com. + + + + + + +<span class="grey">Dusseault Standards Track [Page 47]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-48" id="page-48" href="#page-48" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + >>Request + + MKCOL /webdisc/xfiles/ HTTP/1.1 + Host: www.example.com + + + >>Response + + HTTP/1.1 201 Created + +<span class="h3"><h3><a class="selflink" name="section-9.4" href="#section-9.4">9.4</a>. GET, HEAD for Collections</h3></span> + + The semantics of GET are unchanged when applied to a collection, + since GET is defined as, "retrieve whatever information (in the form + of an entity) is identified by the Request-URI" [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>]. GET, when + applied to a collection, may return the contents of an "index.html" + resource, a human-readable view of the contents of the collection, or + something else altogether. Hence, it is possible that the result of + a GET on a collection will bear no correlation to the membership of + the collection. + + Similarly, since the definition of HEAD is a GET without a response + message body, the semantics of HEAD are unmodified when applied to + collection resources. + +<span class="h3"><h3><a class="selflink" name="section-9.5" href="#section-9.5">9.5</a>. POST for Collections</h3></span> + + Since by definition the actual function performed by POST is + determined by the server and often depends on the particular + resource, the behavior of POST when applied to collections cannot be + meaningfully modified because it is largely undefined. Thus, the + semantics of POST are unmodified when applied to a collection. + +<span class="h3"><h3><a class="selflink" name="section-9.6" href="#section-9.6">9.6</a>. DELETE Requirements</h3></span> + + DELETE is defined in <a href="http://tools.ietf.org/html/rfc2616#section-9.7">[RFC2616], Section 9.7</a>, to "delete the resource + identified by the Request-URI". However, WebDAV changes some DELETE + handling requirements. + + A server processing a successful DELETE request: + + MUST destroy locks rooted on the deleted resource + + MUST remove the mapping from the Request-URI to any resource. + + Thus, after a successful DELETE operation (and in the absence of + other actions), a subsequent GET/HEAD/PROPFIND request to the target + Request-URI MUST return 404 (Not Found). + + + +<span class="grey">Dusseault Standards Track [Page 48]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-49" id="page-49" href="#page-49" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-9.6.1" href="#section-9.6.1">9.6.1</a>. DELETE for Collections</h4></span> + + The DELETE method on a collection MUST act as if a "Depth: infinity" + header was used on it. A client MUST NOT submit a Depth header with + a DELETE on a collection with any value but infinity. + + DELETE instructs that the collection specified in the Request-URI and + all resources identified by its internal member URLs are to be + deleted. + + If any resource identified by a member URL cannot be deleted, then + all of the member's ancestors MUST NOT be deleted, so as to maintain + URL namespace consistency. + + Any headers included with DELETE MUST be applied in processing every + resource to be deleted. + + When the DELETE method has completed processing, it MUST result in a + consistent URL namespace. + + If an error occurs deleting a member resource (a resource other than + the resource identified in the Request-URI), then the response can be + a 207 (Multi-Status). Multi-Status is used here to indicate which + internal resources could NOT be deleted, including an error code, + which should help the client understand which resources caused the + failure. For example, the Multi-Status body could include a response + with status 423 (Locked) if an internal resource was locked. + + The server MAY return a 4xx status response, rather than a 207, if + the request failed completely. + + 424 (Failed Dependency) status codes SHOULD NOT be in the 207 (Multi- + Status) response for DELETE. They can be safely left out because the + client will know that the ancestors of a resource could not be + deleted when the client receives an error for the ancestor's progeny. + Additionally, 204 (No Content) errors SHOULD NOT be returned in the + 207 (Multi-Status). The reason for this prohibition is that 204 (No + Content) is the default success code. + +<span class="h4"><h4><a class="selflink" name="section-9.6.2" href="#section-9.6.2">9.6.2</a>. Example - DELETE</h4></span> + + >>Request + + DELETE /container/ HTTP/1.1 + Host: www.example.com + + + + + + +<span class="grey">Dusseault Standards Track [Page 49]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-50" id="page-50" href="#page-50" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <d:multistatus xmlns:d="DAV:"> + <d:response> + <d:href>http://www.example.com/container/resource3</d:href> + <d:status>HTTP/1.1 423 Locked</d:status> + <d:error><d:lock-token-submitted/></d:error> + </d:response> + </d:multistatus> + + In this example, the attempt to delete + http://www.example.com/container/resource3 failed because it is + locked, and no lock token was submitted with the request. + Consequently, the attempt to delete http://www.example.com/container/ + also failed. Thus, the client knows that the attempt to delete + http://www.example.com/container/ must have also failed since the + parent cannot be deleted unless its child has also been deleted. + Even though a Depth header has not been included, a depth of infinity + is assumed because the method is on a collection. + +<span class="h3"><h3><a class="selflink" name="section-9.7" href="#section-9.7">9.7</a>. PUT Requirements</h3></span> + +<span class="h4"><h4><a class="selflink" name="section-9.7.1" href="#section-9.7.1">9.7.1</a>. PUT for Non-Collection Resources</h4></span> + + A PUT performed on an existing resource replaces the GET response + entity of the resource. Properties defined on the resource may be + recomputed during PUT processing but are not otherwise affected. For + example, if a server recognizes the content type of the request body, + it may be able to automatically extract information that could be + profitably exposed as properties. + + A PUT that would result in the creation of a resource without an + appropriately scoped parent collection MUST fail with a 409 + (Conflict). + + A PUT request allows a client to indicate what media type an entity + body has, and whether it should change if overwritten. Thus, a + client SHOULD provide a Content-Type for a new resource if any is + known. If the client does not provide a Content-Type for a new + resource, the server MAY create a resource with no Content-Type + assigned, or it MAY attempt to assign a Content-Type. + + + + + +<span class="grey">Dusseault Standards Track [Page 50]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-51" id="page-51" href="#page-51" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Note that although a recipient ought generally to treat metadata + supplied with an HTTP request as authoritative, in practice there's + no guarantee that a server will accept client-supplied metadata + (e.g., any request header beginning with "Content-"). Many servers + do not allow configuring the Content-Type on a per-resource basis in + the first place. Thus, clients can't always rely on the ability to + directly influence the content type by including a Content-Type + request header. + +<span class="h4"><h4><a class="selflink" name="section-9.7.2" href="#section-9.7.2">9.7.2</a>. PUT for Collections</h4></span> + + This specification does not define the behavior of the PUT method for + existing collections. A PUT request to an existing collection MAY be + treated as an error (405 Method Not Allowed). + + The MKCOL method is defined to create collections. + +<span class="h3"><h3><a class="selflink" name="section-9.8" href="#section-9.8">9.8</a>. COPY Method</h3></span> + + The COPY method creates a duplicate of the source resource identified + by the Request-URI, in the destination resource identified by the URI + in the Destination header. The Destination header MUST be present. + The exact behavior of the COPY method depends on the type of the + source resource. + + All WebDAV-compliant resources MUST support the COPY method. + However, support for the COPY method does not guarantee the ability + to copy a resource. For example, separate programs may control + resources on the same server. As a result, it may not be possible to + copy a resource to a location that appears to be on the same server. + + This method is idempotent, but not safe (see <a href="http://tools.ietf.org/html/rfc2616#section-9.1">Section 9.1 of + [RFC2616]</a>). Responses to this method MUST NOT be cached. + +<span class="h4"><h4><a class="selflink" name="section-9.8.1" href="#section-9.8.1">9.8.1</a>. COPY for Non-collection Resources</h4></span> + + When the source resource is not a collection, the result of the COPY + method is the creation of a new resource at the destination whose + state and behavior match that of the source resource as closely as + possible. Since the environment at the destination may be different + than at the source due to factors outside the scope of control of the + server, such as the absence of resources required for correct + operation, it may not be possible to completely duplicate the + behavior of the resource at the destination. Subsequent alterations + to the destination resource will not modify the source resource. + Subsequent alterations to the source resource will not modify the + destination resource. + + + + +<span class="grey">Dusseault Standards Track [Page 51]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-52" id="page-52" href="#page-52" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-9.8.2" href="#section-9.8.2">9.8.2</a>. COPY for Properties</h4></span> + + After a successful COPY invocation, all dead properties on the source + resource SHOULD be duplicated on the destination resource. Live + properties described in this document SHOULD be duplicated as + identically behaving live properties at the destination resource, but + not necessarily with the same values. Servers SHOULD NOT convert + live properties into dead properties on the destination resource, + because clients may then draw incorrect conclusions about the state + or functionality of a resource. Note that some live properties are + defined such that the absence of the property has a specific meaning + (e.g., a flag with one meaning if present, and the opposite if + absent), and in these cases, a successful COPY might result in the + property being reported as "Not Found" in subsequent requests. + + When the destination is an unmapped URL, a COPY operation creates a + new resource much like a PUT operation does. Live properties that + are related to resource creation (such as DAV:creationdate) should + have their values set accordingly. + +<span class="h4"><h4><a class="selflink" name="section-9.8.3" href="#section-9.8.3">9.8.3</a>. COPY for Collections</h4></span> + + The COPY method on a collection without a Depth header MUST act as if + a Depth header with value "infinity" was included. A client may + submit a Depth header on a COPY on a collection with a value of "0" + or "infinity". Servers MUST support the "0" and "infinity" Depth + header behaviors on WebDAV-compliant resources. + + An infinite-depth COPY instructs that the collection resource + identified by the Request-URI is to be copied to the location + identified by the URI in the Destination header, and all its internal + member resources are to be copied to a location relative to it, + recursively through all levels of the collection hierarchy. Note + that an infinite-depth COPY of /A/ into /A/B/ could lead to infinite + recursion if not handled correctly. + + A COPY of "Depth: 0" only instructs that the collection and its + properties, but not resources identified by its internal member URLs, + are to be copied. + + Any headers included with a COPY MUST be applied in processing every + resource to be copied with the exception of the Destination header. + + The Destination header only specifies the destination URI for the + Request-URI. When applied to members of the collection identified by + the Request-URI, the value of Destination is to be modified to + reflect the current location in the hierarchy. So, if the Request- + URI is /a/ with Host header value http://example.com/ and the + + + +<span class="grey">Dusseault Standards Track [Page 52]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-53" id="page-53" href="#page-53" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Destination is http://example.com/b/, then when + http://example.com/a/c/d is processed, it must use a Destination of + http://example.com/b/c/d. + + When the COPY method has completed processing, it MUST have created a + consistent URL namespace at the destination (see <a href="#section-5.1">Section 5.1</a> for the + definition of namespace consistency). However, if an error occurs + while copying an internal collection, the server MUST NOT copy any + resources identified by members of this collection (i.e., the server + must skip this subtree), as this would create an inconsistent + namespace. After detecting an error, the COPY operation SHOULD try + to finish as much of the original copy operation as possible (i.e., + the server should still attempt to copy other subtrees and their + members that are not descendants of an error-causing collection). + + So, for example, if an infinite-depth copy operation is performed on + collection /a/, which contains collections /a/b/ and /a/c/, and an + error occurs copying /a/b/, an attempt should still be made to copy + /a/c/. Similarly, after encountering an error copying a non- + collection resource as part of an infinite-depth copy, the server + SHOULD try to finish as much of the original copy operation as + possible. + + If an error in executing the COPY method occurs with a resource other + than the resource identified in the Request-URI, then the response + MUST be a 207 (Multi-Status), and the URL of the resource causing the + failure MUST appear with the specific error. + + The 424 (Failed Dependency) status code SHOULD NOT be returned in the + 207 (Multi-Status) response from a COPY method. These responses can + be safely omitted because the client will know that the progeny of a + resource could not be copied when the client receives an error for + the parent. Additionally, 201 (Created)/204 (No Content) status + codes SHOULD NOT be returned as values in 207 (Multi-Status) + responses from COPY methods. They, too, can be safely omitted + because they are the default success codes. + +<span class="h4"><h4><a class="selflink" name="section-9.8.4" href="#section-9.8.4">9.8.4</a>. COPY and Overwriting Destination Resources</h4></span> + + If a COPY request has an Overwrite header with a value of "F", and a + resource exists at the Destination URL, the server MUST fail the + request. + + When a server executes a COPY request and overwrites a destination + resource, the exact behavior MAY depend on many factors, including + WebDAV extension capabilities (see particularly [<a href="http://tools.ietf.org/html/rfc3253" title="" versioning extensions to webdav distributed authoring and>RFC3253</a>]). For + + + + + +<span class="grey">Dusseault Standards Track [Page 53]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-54" id="page-54" href="#page-54" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + example, when an ordinary resource is overwritten, the server could + delete the target resource before doing the copy, or could do an in- + place overwrite to preserve live properties. + + When a collection is overwritten, the membership of the destination + collection after the successful COPY request MUST be the same + membership as the source collection immediately before the COPY. + Thus, merging the membership of the source and destination + collections together in the destination is not a compliant behavior. + + In general, if clients require the state of the destination URL to be + wiped out prior to a COPY (e.g., to force live properties to be + reset), then the client could send a DELETE to the destination before + the COPY request to ensure this reset. + +<span class="h4"><h4><a class="selflink" name="section-9.8.5" href="#section-9.8.5">9.8.5</a>. Status Codes</h4></span> + + In addition to the general status codes possible, the following + status codes have specific applicability to COPY: + + 201 (Created) - The source resource was successfully copied. The + COPY operation resulted in the creation of a new resource. + + 204 (No Content) - The source resource was successfully copied to a + preexisting destination resource. + + 207 (Multi-Status) - Multiple resources were to be affected by the + COPY, but errors on some of them prevented the operation from taking + place. Specific error messages, together with the most appropriate + of the source and destination URLs, appear in the body of the multi- + status response. For example, if a destination resource was locked + and could not be overwritten, then the destination resource URL + appears with the 423 (Locked) status. + + 403 (Forbidden) - The operation is forbidden. A special case for + COPY could be that the source and destination resources are the same + resource. + + 409 (Conflict) - A resource cannot be created at the destination + until one or more intermediate collections have been created. The + server MUST NOT create those intermediate collections automatically. + + 412 (Precondition Failed) - A precondition header check failed, e.g., + the Overwrite header is "F" and the destination URL is already mapped + to a resource. + + + + + + +<span class="grey">Dusseault Standards Track [Page 54]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-55" id="page-55" href="#page-55" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + 423 (Locked) - The destination resource, or resource within the + destination collection, was locked. This response SHOULD contain the + 'lock-token-submitted' precondition element. + + 502 (Bad Gateway) - This may occur when the destination is on another + server, repository, or URL namespace. Either the source namespace + does not support copying to the destination namespace, or the + destination namespace refuses to accept the resource. The client may + wish to try GET/PUT and PROPFIND/PROPPATCH instead. + + 507 (Insufficient Storage) - The destination resource does not have + sufficient space to record the state of the resource after the + execution of this method. + +<span class="h4"><h4><a class="selflink" name="section-9.8.6" href="#section-9.8.6">9.8.6</a>. Example - COPY with Overwrite</h4></span> + + This example shows resource + http://www.example.com/~fielding/index.html being copied to the + location http://www.example.com/users/f/fielding/index.html. The 204 + (No Content) status code indicates that the existing resource at the + destination was overwritten. + + >>Request + + COPY /~fielding/index.html HTTP/1.1 + Host: www.example.com + Destination: http://www.example.com/users/f/fielding/index.html + + >>Response + + HTTP/1.1 204 No Content + +<span class="h4"><h4><a class="selflink" name="section-9.8.7" href="#section-9.8.7">9.8.7</a>. Example - COPY with No Overwrite</h4></span> + + The following example shows the same copy operation being performed, + but with the Overwrite header set to "F." A response of 412 + (Precondition Failed) is returned because the destination URL is + already mapped to a resource. + + >>Request + + COPY /~fielding/index.html HTTP/1.1 + Host: www.example.com + Destination: http://www.example.com/users/f/fielding/index.html + Overwrite: F + + + + + + +<span class="grey">Dusseault Standards Track [Page 55]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-56" id="page-56" href="#page-56" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + >>Response + + HTTP/1.1 412 Precondition Failed + +<span class="h4"><h4><a class="selflink" name="section-9.8.8" href="#section-9.8.8">9.8.8</a>. Example - COPY of a Collection</h4></span> + + >>Request + + COPY /container/ HTTP/1.1 + Host: www.example.com + Destination: http://www.example.com/othercontainer/ + Depth: infinity + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + + <d:multistatus xmlns:d="DAV:"> + <d:response> + <d:href>http://www.example.com/othercontainer/R2/</d:href> + <d:status>HTTP/1.1 423 Locked</d:status> + <d:error><d:lock-token-submitted/></d:error> + </d:response> + </d:multistatus> + + The Depth header is unnecessary as the default behavior of COPY on a + collection is to act as if a "Depth: infinity" header had been + submitted. In this example, most of the resources, along with the + collection, were copied successfully. However, the collection R2 + failed because the destination R2 is locked. Because there was an + error copying R2, none of R2's members were copied. However, no + errors were listed for those members due to the error minimization + rules. + +<span class="h3"><h3><a class="selflink" name="section-9.9" href="#section-9.9">9.9</a>. MOVE Method</h3></span> + + The MOVE operation on a non-collection resource is the logical + equivalent of a copy (COPY), followed by consistency maintenance + processing, followed by a delete of the source, where all three + actions are performed in a single operation. The consistency + maintenance step allows the server to perform updates caused by the + move, such as updating all URLs, other than the Request-URI that + identifies the source resource, to point to the new destination + resource. + + + +<span class="grey">Dusseault Standards Track [Page 56]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-57" id="page-57" href="#page-57" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + The Destination header MUST be present on all MOVE methods and MUST + follow all COPY requirements for the COPY part of the MOVE method. + All WebDAV-compliant resources MUST support the MOVE method. + + Support for the MOVE method does not guarantee the ability to move a + resource to a particular destination. For example, separate programs + may actually control different sets of resources on the same server. + Therefore, it may not be possible to move a resource within a + namespace that appears to belong to the same server. + + If a resource exists at the destination, the destination resource + will be deleted as a side-effect of the MOVE operation, subject to + the restrictions of the Overwrite header. + + This method is idempotent, but not safe (see <a href="http://tools.ietf.org/html/rfc2616#section-9.1">Section 9.1 of + [RFC2616]</a>). Responses to this method MUST NOT be cached. + +<span class="h4"><h4><a class="selflink" name="section-9.9.1" href="#section-9.9.1">9.9.1</a>. MOVE for Properties</h4></span> + + Live properties described in this document SHOULD be moved along with + the resource, such that the resource has identically behaving live + properties at the destination resource, but not necessarily with the + same values. Note that some live properties are defined such that + the absence of the property has a specific meaning (e.g., a flag with + one meaning if present, and the opposite if absent), and in these + cases, a successful MOVE might result in the property being reported + as "Not Found" in subsequent requests. If the live properties will + not work the same way at the destination, the server MAY fail the + request. + + MOVE is frequently used by clients to rename a file without changing + its parent collection, so it's not appropriate to reset all live + properties that are set at resource creation. For example, the DAV: + creationdate property value SHOULD remain the same after a MOVE. + + Dead properties MUST be moved along with the resource. + +<span class="h4"><h4><a class="selflink" name="section-9.9.2" href="#section-9.9.2">9.9.2</a>. MOVE for Collections</h4></span> + + A MOVE with "Depth: infinity" instructs that the collection + identified by the Request-URI be moved to the address specified in + the Destination header, and all resources identified by its internal + member URLs are to be moved to locations relative to it, recursively + through all levels of the collection hierarchy. + + The MOVE method on a collection MUST act as if a "Depth: infinity" + header was used on it. A client MUST NOT submit a Depth header on a + MOVE on a collection with any value but "infinity". + + + +<span class="grey">Dusseault Standards Track [Page 57]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-58" id="page-58" href="#page-58" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Any headers included with MOVE MUST be applied in processing every + resource to be moved with the exception of the Destination header. + The behavior of the Destination header is the same as given for COPY + on collections. + + When the MOVE method has completed processing, it MUST have created a + consistent URL namespace at both the source and destination (see + <a href="#section-5.1">Section 5.1</a> for the definition of namespace consistency). However, + if an error occurs while moving an internal collection, the server + MUST NOT move any resources identified by members of the failed + collection (i.e., the server must skip the error-causing subtree), as + this would create an inconsistent namespace. In this case, after + detecting the error, the move operation SHOULD try to finish as much + of the original move as possible (i.e., the server should still + attempt to move other subtrees and the resources identified by their + members that are not descendants of an error-causing collection). + So, for example, if an infinite-depth move is performed on collection + /a/, which contains collections /a/b/ and /a/c/, and an error occurs + moving /a/b/, an attempt should still be made to try moving /a/c/. + Similarly, after encountering an error moving a non-collection + resource as part of an infinite-depth move, the server SHOULD try to + finish as much of the original move operation as possible. + + If an error occurs with a resource other than the resource identified + in the Request-URI, then the response MUST be a 207 (Multi-Status), + and the errored resource's URL MUST appear with the specific error. + + The 424 (Failed Dependency) status code SHOULD NOT be returned in the + 207 (Multi-Status) response from a MOVE method. These errors can be + safely omitted because the client will know that the progeny of a + resource could not be moved when the client receives an error for the + parent. Additionally, 201 (Created)/204 (No Content) responses + SHOULD NOT be returned as values in 207 (Multi-Status) responses from + a MOVE. These responses can be safely omitted because they are the + default success codes. + +<span class="h4"><h4><a class="selflink" name="section-9.9.3" href="#section-9.9.3">9.9.3</a>. MOVE and the Overwrite Header</h4></span> + + If a resource exists at the destination and the Overwrite header is + "T", then prior to performing the move, the server MUST perform a + DELETE with "Depth: infinity" on the destination resource. If the + Overwrite header is set to "F", then the operation will fail. + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 58]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-59" id="page-59" href="#page-59" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-9.9.4" href="#section-9.9.4">9.9.4</a>. Status Codes</h4></span> + + In addition to the general status codes possible, the following + status codes have specific applicability to MOVE: + + 201 (Created) - The source resource was successfully moved, and a new + URL mapping was created at the destination. + + 204 (No Content) - The source resource was successfully moved to a + URL that was already mapped. + + 207 (Multi-Status) - Multiple resources were to be affected by the + MOVE, but errors on some of them prevented the operation from taking + place. Specific error messages, together with the most appropriate + of the source and destination URLs, appear in the body of the multi- + status response. For example, if a source resource was locked and + could not be moved, then the source resource URL appears with the 423 + (Locked) status. + + 403 (Forbidden) - Among many possible reasons for forbidding a MOVE + operation, this status code is recommended for use when the source + and destination resources are the same. + + 409 (Conflict) - A resource cannot be created at the destination + until one or more intermediate collections have been created. The + server MUST NOT create those intermediate collections automatically. + Or, the server was unable to preserve the behavior of the live + properties and still move the resource to the destination (see + 'preserved-live-properties' postcondition). + + 412 (Precondition Failed) - A condition header failed. Specific to + MOVE, this could mean that the Overwrite header is "F" and the + destination URL is already mapped to a resource. + + 423 (Locked) - The source or the destination resource, the source or + destination resource parent, or some resource within the source or + destination collection, was locked. This response SHOULD contain the + 'lock-token-submitted' precondition element. + + 502 (Bad Gateway) - This may occur when the destination is on another + server and the destination server refuses to accept the resource. + This could also occur when the destination is on another sub-section + of the same server namespace. + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 59]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-60" id="page-60" href="#page-60" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-9.9.5" href="#section-9.9.5">9.9.5</a>. Example - MOVE of a Non-Collection</h4></span> + + This example shows resource + http://www.example.com/~fielding/index.html being moved to the + location http://www.example.com/users/f/fielding/index.html. The + contents of the destination resource would have been overwritten if + the destination URL was already mapped to a resource. In this case, + since there was nothing at the destination resource, the response + code is 201 (Created). + + >>Request + + MOVE /~fielding/index.html HTTP/1.1 + Host: www.example.com + Destination: http://www.example/users/f/fielding/index.html + + >>Response + + HTTP/1.1 201 Created + Location: http://www.example.com/users/f/fielding/index.html + +<span class="h4"><h4><a class="selflink" name="section-9.9.6" href="#section-9.9.6">9.9.6</a>. Example - MOVE of a Collection</h4></span> + + >>Request + + MOVE /container/ HTTP/1.1 + Host: www.example.com + Destination: http://www.example.com/othercontainer/ + Overwrite: F + If: (<urn:uuid:fe184f2e-6eec-41d0-c765-01adc56e6bb4>) + (<urn:uuid:e454f3f3-acdc-452a-56c7-00a5c91e4b77>) + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <d:multistatus xmlns:d='DAV:'> + <d:response> + <d:href>http://www.example.com/othercontainer/C2/</d:href> + <d:status>HTTP/1.1 423 Locked</d:status> + <d:error><d:lock-token-submitted/></d:error> + </d:response> + </d:multistatus> + + + + + +<span class="grey">Dusseault Standards Track [Page 60]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-61" id="page-61" href="#page-61" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + In this example, the client has submitted a number of lock tokens + with the request. A lock token will need to be submitted for every + resource, both source and destination, anywhere in the scope of the + method, that is locked. In this case, the proper lock token was not + submitted for the destination + http://www.example.com/othercontainer/C2/. This means that the + resource /container/C2/ could not be moved. Because there was an + error moving /container/C2/, none of /container/C2's members were + moved. However, no errors were listed for those members due to the + error minimization rules. User agent authentication has previously + occurred via a mechanism outside the scope of the HTTP protocol, in + an underlying transport layer. + +<span class="h3"><h3><a class="selflink" name="section-9.10" href="#section-9.10">9.10</a>. LOCK Method</h3></span> + + The following sections describe the LOCK method, which is used to + take out a lock of any access type and to refresh an existing lock. + These sections on the LOCK method describe only those semantics that + are specific to the LOCK method and are independent of the access + type of the lock being requested. + + Any resource that supports the LOCK method MUST, at minimum, support + the XML request and response formats defined herein. + + This method is neither idempotent nor safe (see <a href="http://tools.ietf.org/html/rfc2616#section-9.1">Section 9.1 of + [RFC2616]</a>). Responses to this method MUST NOT be cached. + +<span class="h4"><h4><a class="selflink" name="section-9.10.1" href="#section-9.10.1">9.10.1</a>. Creating a Lock on an Existing Resource</h4></span> + + A LOCK request to an existing resource will create a lock on the + resource identified by the Request-URI, provided the resource is not + already locked with a conflicting lock. The resource identified in + the Request-URI becomes the root of the lock. LOCK method requests + to create a new lock MUST have an XML request body. The server MUST + preserve the information provided by the client in the 'owner' + element in the LOCK request. The LOCK request MAY have a Timeout + header. + + When a new lock is created, the LOCK response: + + o MUST contain a body with the value of the DAV:lockdiscovery + property in a prop XML element. This MUST contain the full + information about the lock just granted, while information about + other (shared) locks is OPTIONAL. + + o MUST include the Lock-Token response header with the token + associated with the new lock. + + + + +<span class="grey">Dusseault Standards Track [Page 61]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-62" id="page-62" href="#page-62" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-9.10.2" href="#section-9.10.2">9.10.2</a>. Refreshing Locks</h4></span> + + A lock is refreshed by sending a LOCK request to the URL of a + resource within the scope of the lock. This request MUST NOT have a + body and it MUST specify which lock to refresh by using the 'If' + header with a single lock token (only one lock may be refreshed at a + time). The request MAY contain a Timeout header, which a server MAY + accept to change the duration remaining on the lock to the new value. + A server MUST ignore the Depth header on a LOCK refresh. + + If the resource has other (shared) locks, those locks are unaffected + by a lock refresh. Additionally, those locks do not prevent the + named lock from being refreshed. + + The Lock-Token header is not returned in the response for a + successful refresh LOCK request, but the LOCK response body MUST + contain the new value for the DAV:lockdiscovery property. + +<span class="h4"><h4><a class="selflink" name="section-9.10.3" href="#section-9.10.3">9.10.3</a>. Depth and Locking</h4></span> + + The Depth header may be used with the LOCK method. Values other than + 0 or infinity MUST NOT be used with the Depth header on a LOCK + method. All resources that support the LOCK method MUST support the + Depth header. + + A Depth header of value 0 means to just lock the resource specified + by the Request-URI. + + If the Depth header is set to infinity, then the resource specified + in the Request-URI along with all its members, all the way down the + hierarchy, are to be locked. A successful result MUST return a + single lock token. Similarly, if an UNLOCK is successfully executed + on this token, all associated resources are unlocked. Hence, partial + success is not an option for LOCK or UNLOCK. Either the entire + hierarchy is locked or no resources are locked. + + If the lock cannot be granted to all resources, the server MUST + return a Multi-Status response with a 'response' element for at least + one resource that prevented the lock from being granted, along with a + suitable status code for that failure (e.g., 403 (Forbidden) or 423 + (Locked)). Additionally, if the resource causing the failure was not + the resource requested, then the server SHOULD include a 'response' + element for the Request-URI as well, with a 'status' element + containing 424 Failed Dependency. + + If no Depth header is submitted on a LOCK request, then the request + MUST act as if a "Depth:infinity" had been submitted. + + + + +<span class="grey">Dusseault Standards Track [Page 62]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-63" id="page-63" href="#page-63" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-9.10.4" href="#section-9.10.4">9.10.4</a>. Locking Unmapped URLs</h4></span> + + A successful LOCK method MUST result in the creation of an empty + resource that is locked (and that is not a collection) when a + resource did not previously exist at that URL. Later on, the lock + may go away but the empty resource remains. Empty resources MUST + then appear in PROPFIND responses including that URL in the response + scope. A server MUST respond successfully to a GET request to an + empty resource, either by using a 204 No Content response, or by + using 200 OK with a Content-Length header indicating zero length + +<span class="h4"><h4><a class="selflink" name="section-9.10.5" href="#section-9.10.5">9.10.5</a>. Lock Compatibility Table</h4></span> + + The table below describes the behavior that occurs when a lock + request is made on a resource. + + +--------------------------+----------------+-------------------+ + | Current State | Shared Lock OK | Exclusive Lock OK | + +--------------------------+----------------+-------------------+ + | None | True | True | + | Shared Lock | True | False | + | Exclusive Lock | False | False* | + +--------------------------+----------------+-------------------+ + + Legend: True = lock may be granted. False = lock MUST NOT be + granted. *=It is illegal for a principal to request the same lock + twice. + + The current lock state of a resource is given in the leftmost column, + and lock requests are listed in the first row. The intersection of a + row and column gives the result of a lock request. For example, if a + shared lock is held on a resource, and an exclusive lock is + requested, the table entry is "false", indicating that the lock must + not be granted. + +<span class="h4"><h4><a class="selflink" name="section-9.10.6" href="#section-9.10.6">9.10.6</a>. LOCK Responses</h4></span> + + In addition to the general status codes possible, the following + status codes have specific applicability to LOCK: + + 200 (OK) - The LOCK request succeeded and the value of the DAV: + lockdiscovery property is included in the response body. + + 201 (Created) - The LOCK request was to an unmapped URL, the request + succeeded and resulted in the creation of a new resource, and the + value of the DAV:lockdiscovery property is included in the response + body. + + + + +<span class="grey">Dusseault Standards Track [Page 63]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-64" id="page-64" href="#page-64" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + 409 (Conflict) - A resource cannot be created at the destination + until one or more intermediate collections have been created. The + server MUST NOT create those intermediate collections automatically. + + 423 (Locked), potentially with 'no-conflicting-lock' precondition + code - There is already a lock on the resource that is not compatible + with the requested lock (see lock compatibility table above). + + 412 (Precondition Failed), with 'lock-token-matches-request-uri' + precondition code - The LOCK request was made with an If header, + indicating that the client wishes to refresh the given lock. + However, the Request-URI did not fall within the scope of the lock + identified by the token. The lock may have a scope that does not + include the Request-URI, or the lock could have disappeared, or the + token may be invalid. + +<span class="h4"><h4><a class="selflink" name="section-9.10.7" href="#section-9.10.7">9.10.7</a>. Example - Simple Lock Request</h4></span> + + >>Request + + LOCK /workspace/webdav/proposal.doc HTTP/1.1 + Host: example.com + Timeout: Infinite, Second-4100000000 + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + Authorization: Digest username="ejw", + realm="ejw@example.com", nonce="...", + uri="/workspace/webdav/proposal.doc", + response="...", opaque="..." + + <?xml version="1.0" encoding="utf-8" ?> + <D:lockinfo xmlns:D='DAV:'> + <D:lockscope><D:exclusive/></D:lockscope> + <D:locktype><D:write/></D:locktype> + <D:owner> + <D:href>http://example.org/~ejw/contact.html</D:href> + </D:owner> + </D:lockinfo> + + >>Response + + HTTP/1.1 200 OK + Lock-Token: <urn:uuid:e71d4fae-5dec-22d6-fea5-00a0c91e6be4> + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:prop xmlns:D="DAV:"> + + + +<span class="grey">Dusseault Standards Track [Page 64]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-65" id="page-65" href="#page-65" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + <D:lockdiscovery> + <D:activelock> + <D:locktype><D:write/></D:locktype> + <D:lockscope><D:exclusive/></D:lockscope> + <D:depth>infinity</D:depth> + <D:owner> + <D:href>http://example.org/~ejw/contact.html</D:href> + </D:owner> + <D:timeout>Second-604800</D:timeout> + <D:locktoken> + <D:href + >urn:uuid:e71d4fae-5dec-22d6-fea5-00a0c91e6be4</D:href> + </D:locktoken> + <D:lockroot> + <D:href + >http://example.com/workspace/webdav/proposal.doc</D:href> + </D:lockroot> + </D:activelock> + </D:lockdiscovery> + </D:prop> + + + This example shows the successful creation of an exclusive write lock + on resource http://example.com/workspace/webdav/proposal.doc. The + resource http://example.org/~ejw/contact.html contains contact + information for the creator of the lock. The server has an activity- + based timeout policy in place on this resource, which causes the lock + to automatically be removed after 1 week (604800 seconds). Note that + the nonce, response, and opaque fields have not been calculated in + the Authorization request header. + +<span class="h4"><h4><a class="selflink" name="section-9.10.8" href="#section-9.10.8">9.10.8</a>. Example - Refreshing a Write Lock</h4></span> + + >>Request + + LOCK /workspace/webdav/proposal.doc HTTP/1.1 + Host: example.com + Timeout: Infinite, Second-4100000000 + If: (<urn:uuid:e71d4fae-5dec-22d6-fea5-00a0c91e6be4>) + Authorization: Digest username="ejw", + realm="ejw@example.com", nonce="...", + uri="/workspace/webdav/proposal.doc", + response="...", opaque="..." + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 65]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-66" id="page-66" href="#page-66" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + >>Response + + HTTP/1.1 200 OK + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:prop xmlns:D="DAV:"> + <D:lockdiscovery> + <D:activelock> + <D:locktype><D:write/></D:locktype> + <D:lockscope><D:exclusive/></D:lockscope> + <D:depth>infinity</D:depth> + <D:owner> + <D:href>http://example.org/~ejw/contact.html</D:href> + </D:owner> + <D:timeout>Second-604800</D:timeout> + <D:locktoken> + <D:href + >urn:uuid:e71d4fae-5dec-22d6-fea5-00a0c91e6be4</D:href> + </D:locktoken> + <D:lockroot> + <D:href + >http://example.com/workspace/webdav/proposal.doc</D:href> + </D:lockroot> + </D:activelock> + </D:lockdiscovery> + </D:prop> + + + This request would refresh the lock, attempting to reset the timeout + to the new value specified in the timeout header. Notice that the + client asked for an infinite time out but the server choose to ignore + the request. In this example, the nonce, response, and opaque fields + have not been calculated in the Authorization request header. + +<span class="h4"><h4><a class="selflink" name="section-9.10.9" href="#section-9.10.9">9.10.9</a>. Example - Multi-Resource Lock Request</h4></span> + + >>Request + + LOCK /webdav/ HTTP/1.1 + Host: example.com + Timeout: Infinite, Second-4100000000 + Depth: infinity + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + Authorization: Digest username="ejw", + realm="ejw@example.com", nonce="...", + + + +<span class="grey">Dusseault Standards Track [Page 66]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-67" id="page-67" href="#page-67" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + uri="/workspace/webdav/proposal.doc", + response="...", opaque="..." + + <?xml version="1.0" encoding="utf-8" ?> + <D:lockinfo xmlns:D="DAV:"> + <D:locktype><D:write/></D:locktype> + <D:lockscope><D:exclusive/></D:lockscope> + <D:owner> + <D:href>http://example.org/~ejw/contact.html</D:href> + </D:owner> + </D:lockinfo> + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:multistatus xmlns:D="DAV:"> + <D:response> + <D:href>http://example.com/webdav/secret</D:href> + <D:status>HTTP/1.1 403 Forbidden</D:status> + </D:response> + <D:response> + <D:href>http://example.com/webdav/</D:href> + <D:status>HTTP/1.1 424 Failed Dependency</D:status> + </D:response> + </D:multistatus> + + + This example shows a request for an exclusive write lock on a + collection and all its children. In this request, the client has + specified that it desires an infinite-length lock, if available, + otherwise a timeout of 4.1 billion seconds, if available. The + request entity body contains the contact information for the + principal taking out the lock -- in this case, a Web page URL. + + The error is a 403 (Forbidden) response on the resource + http://example.com/webdav/secret. Because this resource could not be + locked, none of the resources were locked. Note also that the a + 'response' element for the Request-URI itself has been included as + required. + + In this example, the nonce, response, and opaque fields have not been + calculated in the Authorization request header. + + + + + +<span class="grey">Dusseault Standards Track [Page 67]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-68" id="page-68" href="#page-68" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-9.11" href="#section-9.11">9.11</a>. UNLOCK Method</h3></span> + + The UNLOCK method removes the lock identified by the lock token in + the Lock-Token request header. The Request-URI MUST identify a + resource within the scope of the lock. + + Note that use of the Lock-Token header to provide the lock token is + not consistent with other state-changing methods, which all require + an If header with the lock token. Thus, the If header is not needed + to provide the lock token. Naturally, when the If header is present, + it has its normal meaning as a conditional header. + + For a successful response to this method, the server MUST delete the + lock entirely. + + If all resources that have been locked under the submitted lock token + cannot be unlocked, then the UNLOCK request MUST fail. + + A successful response to an UNLOCK method does not mean that the + resource is necessarily unlocked. It means that the specific lock + corresponding to the specified token no longer exists. + + Any DAV-compliant resource that supports the LOCK method MUST support + the UNLOCK method. + + This method is idempotent, but not safe (see <a href="http://tools.ietf.org/html/rfc2616#section-9.1">Section 9.1 of + [RFC2616]</a>). Responses to this method MUST NOT be cached. + +<span class="h4"><h4><a class="selflink" name="section-9.11.1" href="#section-9.11.1">9.11.1</a>. Status Codes</h4></span> + + In addition to the general status codes possible, the following + status codes have specific applicability to UNLOCK: + + 204 (No Content) - Normal success response (rather than 200 OK, since + 200 OK would imply a response body, and an UNLOCK success response + does not normally contain a body). + + 400 (Bad Request) - No lock token was provided. + + 403 (Forbidden) - The currently authenticated principal does not have + permission to remove the lock. + + 409 (Conflict), with 'lock-token-matches-request-uri' precondition - + The resource was not locked, or the request was made to a Request-URI + that was not within the scope of the lock. + + + + + + +<span class="grey">Dusseault Standards Track [Page 68]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-69" id="page-69" href="#page-69" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-9.11.2" href="#section-9.11.2">9.11.2</a>. Example - UNLOCK</h4></span> + + >>Request + + UNLOCK /workspace/webdav/info.doc HTTP/1.1 + Host: example.com + Lock-Token: <urn:uuid:a515cfa4-5da4-22e1-f5b5-00a0451e6bf7> + Authorization: Digest username="ejw" + realm="ejw@example.com", nonce="...", + uri="/workspace/webdav/proposal.doc", + response="...", opaque="..." + + >>Response + + HTTP/1.1 204 No Content + + In this example, the lock identified by the lock token + "urn:uuid:a515cfa4-5da4-22e1-f5b5-00a0451e6bf7" is successfully + removed from the resource + http://example.com/workspace/webdav/info.doc. If this lock included + more than just one resource, the lock is removed from all resources + included in the lock. + + In this example, the nonce, response, and opaque fields have not been + calculated in the Authorization request header. + +<span class="h2"><h2><a class="selflink" name="section-10" href="#section-10">10</a>. HTTP Headers for Distributed Authoring</h2></span> + + All DAV headers follow the same basic formatting rules as HTTP + headers. This includes rules like line continuation and how to + combine (or separate) multiple instances of the same header using + commas. + + WebDAV adds two new conditional headers to the set defined in HTTP: + the If and Overwrite headers. + +<span class="h3"><h3><a class="selflink" name="section-10.1" href="#section-10.1">10.1</a>. DAV Header</h3></span> + + DAV = "DAV" ":" #( compliance-class ) + compliance-class = ( "1" | "2" | "3" | extend ) + extend = Coded-URL | token + ; token is defined in <a href="http://tools.ietf.org/html/rfc2616#section-2.2">RFC 2616, Section 2.2</a> + Coded-URL = "<" absolute-URI ">" + ; No linear whitespace (LWS) allowed in Coded-URL + ; absolute-URI defined in <a href="http://tools.ietf.org/html/rfc3986#section-4.3">RFC 3986, Section 4.3</a> + + + + + + +<span class="grey">Dusseault Standards Track [Page 69]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-70" id="page-70" href="#page-70" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + This general-header appearing in the response indicates that the + resource supports the DAV schema and protocol as specified. All DAV- + compliant resources MUST return the DAV header with compliance-class + "1" on all OPTIONS responses. In cases where WebDAV is only + supported in part of the server namespace, an OPTIONS request to non- + WebDAV resources (including "/") SHOULD NOT advertise WebDAV support. + + The value is a comma-separated list of all compliance class + identifiers that the resource supports. Class identifiers may be + Coded-URLs or tokens (as defined by [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>]). Identifiers can + appear in any order. Identifiers that are standardized through the + IETF RFC process are tokens, but other identifiers SHOULD be Coded- + URLs to encourage uniqueness. + + A resource must show class 1 compliance if it shows class 2 or 3 + compliance. In general, support for one compliance class does not + entail support for any other, and in particular, support for + compliance class 3 does not require support for compliance class 2. + Please refer to <a href="#section-18">Section 18</a> for more details on compliance classes + defined in this specification. + + Note that many WebDAV servers do not advertise WebDAV support in + response to "OPTIONS *". + + As a request header, this header allows the client to advertise + compliance with named features when the server needs that + information. Clients SHOULD NOT send this header unless a standards + track specification requires it. Any extension that makes use of + this as a request header will need to carefully consider caching + implications. + +<span class="h3"><h3><a class="selflink" name="section-10.2" href="#section-10.2">10.2</a>. Depth Header</h3></span> + + Depth = "Depth" ":" ("0" | "1" | "infinity") + + The Depth request header is used with methods executed on resources + that could potentially have internal members to indicate whether the + method is to be applied only to the resource ("Depth: 0"), to the + resource and its internal members only ("Depth: 1"), or the resource + and all its members ("Depth: infinity"). + + The Depth header is only supported if a method's definition + explicitly provides for such support. + + The following rules are the default behavior for any method that + supports the Depth header. A method may override these defaults by + defining different behavior in its definition. + + + + +<span class="grey">Dusseault Standards Track [Page 70]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-71" id="page-71" href="#page-71" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Methods that support the Depth header may choose not to support all + of the header's values and may define, on a case-by-case basis, the + behavior of the method if a Depth header is not present. For + example, the MOVE method only supports "Depth: infinity", and if a + Depth header is not present, it will act as if a "Depth: infinity" + header had been applied. + + Clients MUST NOT rely upon methods executing on members of their + hierarchies in any particular order or on the execution being atomic + unless the particular method explicitly provides such guarantees. + + Upon execution, a method with a Depth header will perform as much of + its assigned task as possible and then return a response specifying + what it was able to accomplish and what it failed to do. + + So, for example, an attempt to COPY a hierarchy may result in some of + the members being copied and some not. + + By default, the Depth header does not interact with other headers. + That is, each header on a request with a Depth header MUST be applied + only to the Request-URI if it applies to any resource, unless + specific Depth behavior is defined for that header. + + If a source or destination resource within the scope of the Depth + header is locked in such a way as to prevent the successful execution + of the method, then the lock token for that resource MUST be + submitted with the request in the If request header. + + The Depth header only specifies the behavior of the method with + regards to internal members. If a resource does not have internal + members, then the Depth header MUST be ignored. + +<span class="h3"><h3><a class="selflink" name="section-10.3" href="#section-10.3">10.3</a>. Destination Header</h3></span> + + The Destination request header specifies the URI that identifies a + destination resource for methods such as COPY and MOVE, which take + two URIs as parameters. + + Destination = "Destination" ":" Simple-ref + + + If the Destination value is an absolute-URI (<a href="http://tools.ietf.org/html/rfc3986#section-4.3">Section 4.3 of + [RFC3986]</a>), it may name a different server (or different port or + scheme). If the source server cannot attempt a copy to the remote + server, it MUST fail the request. Note that copying and moving + resources to remote servers is not fully defined in this + specification (e.g., specific error conditions). + + + + +<span class="grey">Dusseault Standards Track [Page 71]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-72" id="page-72" href="#page-72" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + If the Destination value is too long or otherwise unacceptable, the + server SHOULD return 400 (Bad Request), ideally with helpful + information in an error body. + +<span class="h3"><h3><a class="selflink" name="section-10.4" href="#section-10.4">10.4</a>. If Header</h3></span> + + The If request header is intended to have similar functionality to + the If-Match header defined in <a href="http://tools.ietf.org/html/rfc2616#section-14.24">Section 14.24 of [RFC2616]</a>. However, + the If header handles any state token as well as ETags. A typical + example of a state token is a lock token, and lock tokens are the + only state tokens defined in this specification. + +<span class="h4"><h4><a class="selflink" name="section-10.4.1" href="#section-10.4.1">10.4.1</a>. Purpose</h4></span> + + The If header has two distinct purposes: + + o The first purpose is to make a request conditional by supplying a + series of state lists with conditions that match tokens and ETags + to a specific resource. If this header is evaluated and all state + lists fail, then the request MUST fail with a 412 (Precondition + Failed) status. On the other hand, the request can succeed only + if one of the described state lists succeeds. The success + criteria for state lists and matching functions are defined in + Sections <a href="#section-10.4.3">10.4.3</a> and <a href="#section-10.4.4">10.4.4</a>. + + o Additionally, the mere fact that a state token appears in an If + header means that it has been "submitted" with the request. In + general, this is used to indicate that the client has knowledge of + that state token. The semantics for submitting a state token + depend on its type (for lock tokens, please refer to <a href="#section-6">Section 6</a>). + + Note that these two purposes need to be treated distinctly: a state + token counts as being submitted independently of whether the server + actually has evaluated the state list it appears in, and also + independently of whether or not the condition it expressed was found + to be true. + +<span class="h4"><h4><a class="selflink" name="section-10.4.2" href="#section-10.4.2">10.4.2</a>. Syntax</h4></span> + + If = "If" ":" ( 1*No-tag-list | 1*Tagged-list ) + + No-tag-list = List + Tagged-list = Resource-Tag 1*List + + List = "(" 1*Condition ")" + Condition = ["Not"] (State-token | "[" entity-tag "]") + ; entity-tag: see <a href="http://tools.ietf.org/html/rfc2616#section-3.11">Section 3.11 of [RFC2616]</a> + ; No LWS allowed between "[", entity-tag and "]" + + + +<span class="grey">Dusseault Standards Track [Page 72]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-73" id="page-73" href="#page-73" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + State-token = Coded-URL + + Resource-Tag = "<" Simple-ref ">" + ; Simple-ref: see <a href="#section-8.3">Section 8.3</a> + ; No LWS allowed in Resource-Tag + + The syntax distinguishes between untagged lists ("No-tag-list") and + tagged lists ("Tagged-list"). Untagged lists apply to the resource + identified by the Request-URI, while tagged lists apply to the + resource identified by the preceding Resource-Tag. + + A Resource-Tag applies to all subsequent Lists, up to the next + Resource-Tag. + + Note that the two list types cannot be mixed within an If header. + This is not a functional restriction because the No-tag-list syntax + is just a shorthand notation for a Tagged-list production with a + Resource-Tag referring to the Request-URI. + + Each List consists of one or more Conditions. Each Condition is + defined in terms of an entity-tag or state-token, potentially negated + by the prefix "Not". + + Note that the If header syntax does not allow multiple instances of + If headers in a single request. However, the HTTP header syntax + allows extending single header values across multiple lines, by + inserting a line break followed by whitespace (see [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>], <a href="#section-4.2">Section</a> + <a href="#section-4.2">4.2</a>). + +<span class="h4"><h4><a class="selflink" name="section-10.4.3" href="#section-10.4.3">10.4.3</a>. List Evaluation</h4></span> + + A Condition that consists of a single entity-tag or state-token + evaluates to true if the resource matches the described state (where + the individual matching functions are defined below in + <a href="#section-10.4.4">Section 10.4.4</a>). Prefixing it with "Not" reverses the result of the + evaluation (thus, the "Not" applies only to the subsequent entity-tag + or state-token). + + Each List production describes a series of conditions. The whole + list evaluates to true if and only if each condition evaluates to + true (that is, the list represents a logical conjunction of + Conditions). + + Each No-tag-list and Tagged-list production may contain one or more + Lists. They evaluate to true if and only if any of the contained + lists evaluates to true (that is, if there's more than one List, that + List sequence represents a logical disjunction of the Lists). + + + + +<span class="grey">Dusseault Standards Track [Page 73]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-74" id="page-74" href="#page-74" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Finally, the whole If header evaluates to true if and only if at + least one of the No-tag-list or Tagged-list productions evaluates to + true. If the header evaluates to false, the server MUST reject the + request with a 412 (Precondition Failed) status. Otherwise, + execution of the request can proceed as if the header wasn't present. + +<span class="h4"><h4><a class="selflink" name="section-10.4.4" href="#section-10.4.4">10.4.4</a>. Matching State Tokens and ETags</h4></span> + + When performing If header processing, the definition of a matching + state token or entity tag is as follows: + + Identifying a resource: The resource is identified by the URI along + with the token, in tagged list production, or by the Request-URI in + untagged list production. + + Matching entity tag: Where the entity tag matches an entity tag + associated with the identified resource. Servers MUST use either the + weak or the strong comparison function defined in <a href="http://tools.ietf.org/html/rfc2616#section-13.3.3">Section 13.3.3 of + [RFC2616]</a>. + + Matching state token: Where there is an exact match between the state + token in the If header and any state token on the identified + resource. A lock state token is considered to match if the resource + is anywhere in the scope of the lock. + + Handling unmapped URLs: For both ETags and state tokens, treat as if + the URL identified a resource that exists but does not have the + specified state. + +<span class="h4"><h4><a class="selflink" name="section-10.4.5" href="#section-10.4.5">10.4.5</a>. If Header and Non-DAV-Aware Proxies</h4></span> + + Non-DAV-aware proxies will not honor the If header, since they will + not understand the If header, and HTTP requires non-understood + headers to be ignored. When communicating with HTTP/1.1 proxies, the + client MUST use the "Cache-Control: no-cache" request header so as to + prevent the proxy from improperly trying to service the request from + its cache. When dealing with HTTP/1.0 proxies, the "Pragma: no- + cache" request header MUST be used for the same reason. + + Because in general clients may not be able to reliably detect non- + DAV-aware intermediates, they are advised to always prevent caching + using the request directives mentioned above. + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 74]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-75" id="page-75" href="#page-75" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-10.4.6" href="#section-10.4.6">10.4.6</a>. Example - No-tag Production</h4></span> + + If: (<urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2> + ["I am an ETag"]) + (["I am another ETag"]) + + The previous header would require that the resource identified in the + Request-URI be locked with the specified lock token and be in the + state identified by the "I am an ETag" ETag or in the state + identified by the second ETag "I am another ETag". + + To put the matter more plainly one can think of the previous If + header as expressing the condition below: + + ( + is-locked-with(urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2) AND + matches-etag("I am an ETag") + ) + OR + ( + matches-etag("I am another ETag") + ) + +<span class="h4"><h4><a class="selflink" name="section-10.4.7" href="#section-10.4.7">10.4.7</a>. Example - Using "Not" with No-tag Production</h4></span> + + If: (Not <urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2> + <urn:uuid:58f202ac-22cf-11d1-b12d-002035b29092>) + + This If header requires that the resource must not be locked with a + lock having the lock token + urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2 and must be locked by a + lock with the lock token + urn:uuid:58f202ac-22cf-11d1-b12d-002035b29092. + +<span class="h4"><h4><a class="selflink" name="section-10.4.8" href="#section-10.4.8">10.4.8</a>. Example - Causing a Condition to Always Evaluate to True</h4></span> + + There may be cases where a client wishes to submit state tokens, but + doesn't want the request to fail just because the state token isn't + current anymore. One simple way to do this is to include a Condition + that is known to always evaluate to true, such as in: + + If: (<urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2>) + (Not <DAV:no-lock>) + + "DAV:no-lock" is known to never represent a current lock token. Lock + tokens are assigned by the server, following the uniqueness + requirements described in <a href="#section-6.5">Section 6.5</a>, therefore cannot use the + "DAV:" scheme. Thus, by applying "Not" to a state token that is + + + +<span class="grey">Dusseault Standards Track [Page 75]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-76" id="page-76" href="#page-76" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + known not to be current, the Condition always evaluates to true. + Consequently, the whole If header will always evaluate to true, and + the lock token urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2 will be + submitted in any case. + +<span class="h4"><h4><a class="selflink" name="section-10.4.9" href="#section-10.4.9">10.4.9</a>. Example - Tagged List If Header in COPY</h4></span> + + >>Request + + COPY /resource1 HTTP/1.1 + Host: www.example.com + Destination: /resource2 + If: </resource1> + (<urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2> + [W/"A weak ETag"]) (["strong ETag"]) + + In this example, http://www.example.com/resource1 is being copied to + http://www.example.com/resource2. When the method is first applied + to http://www.example.com/resource1, resource1 must be in the state + specified by "(<urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2> [W/"A + weak ETag"]) (["strong ETag"])". That is, either it must be locked + with a lock token of "urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2" + and have a weak entity tag W/"A weak ETag" or it must have a strong + entity tag "strong ETag". + +<span class="h4"><h4><a class="selflink" name="section-10.4.10" href="#section-10.4.10">10.4.10</a>. Example - Matching Lock Tokens with Collection Locks</h4></span> + + DELETE /specs/rfc2518.txt HTTP/1.1 + Host: www.example.com + If: <http://www.example.com/specs/> + (<urn:uuid:181d4fae-7d8c-11d0-a765-00a0c91e6bf2>) + + For this example, the lock token must be compared to the identified + resource, which is the 'specs' collection identified by the URL in + the tagged list production. If the 'specs' collection is not locked + by a lock with the specified lock token, the request MUST fail. + Otherwise, this request could succeed, because the If header + evaluates to true, and because the lock token for the lock affecting + the affected resource has been submitted. + +<span class="h4"><h4><a class="selflink" name="section-10.4.11" href="#section-10.4.11">10.4.11</a>. Example - Matching ETags on Unmapped URLs</h4></span> + + Consider a collection "/specs" that does not contain the member + "/specs/rfc2518.doc". In this case, the If header + + If: </specs/rfc2518.doc> (["4217"]) + + + + + +<span class="grey">Dusseault Standards Track [Page 76]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-77" id="page-77" href="#page-77" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + will evaluate to false (the URI isn't mapped, thus the resource + identified by the URI doesn't have an entity matching the ETag + "4217"). + + On the other hand, an If header of + + If: </specs/rfc2518.doc> (Not ["4217"]) + + will consequently evaluate to true. + + Note that, as defined above in <a href="#section-10.4.4">Section 10.4.4</a>, the same + considerations apply to matching state tokens. + +<span class="h3"><h3><a class="selflink" name="section-10.5" href="#section-10.5">10.5</a>. Lock-Token Header</h3></span> + + Lock-Token = "Lock-Token" ":" Coded-URL + + The Lock-Token request header is used with the UNLOCK method to + identify the lock to be removed. The lock token in the Lock-Token + request header MUST identify a lock that contains the resource + identified by Request-URI as a member. + + The Lock-Token response header is used with the LOCK method to + indicate the lock token created as a result of a successful LOCK + request to create a new lock. + +<span class="h3"><h3><a class="selflink" name="section-10.6" href="#section-10.6">10.6</a>. Overwrite Header</h3></span> + + Overwrite = "Overwrite" ":" ("T" | "F") + + The Overwrite request header specifies whether the server should + overwrite a resource mapped to the destination URL during a COPY or + MOVE. A value of "F" states that the server must not perform the + COPY or MOVE operation if the destination URL does map to a resource. + If the overwrite header is not included in a COPY or MOVE request, + then the resource MUST treat the request as if it has an overwrite + header of value "T". While the Overwrite header appears to duplicate + the functionality of using an "If-Match: *" header (see [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>]), + If-Match applies only to the Request-URI, and not to the Destination + of a COPY or MOVE. + + If a COPY or MOVE is not performed due to the value of the Overwrite + header, the method MUST fail with a 412 (Precondition Failed) status + code. The server MUST do authorization checks before checking this + or any conditional header. + + All DAV-compliant resources MUST support the Overwrite header. + + + + +<span class="grey">Dusseault Standards Track [Page 77]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-78" id="page-78" href="#page-78" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-10.7" href="#section-10.7">10.7</a>. Timeout Request Header</h3></span> + + TimeOut = "Timeout" ":" 1#TimeType + TimeType = ("Second-" DAVTimeOutVal | "Infinite") + ; No LWS allowed within TimeType + DAVTimeOutVal = 1*DIGIT + + Clients MAY include Timeout request headers in their LOCK requests. + However, the server is not required to honor or even consider these + requests. Clients MUST NOT submit a Timeout request header with any + method other than a LOCK method. + + The "Second" TimeType specifies the number of seconds that will + elapse between granting of the lock at the server, and the automatic + removal of the lock. The timeout value for TimeType "Second" MUST + NOT be greater than 2^32-1. + + See <a href="#section-6.6">Section 6.6</a> for a description of lock timeout behavior. + +<span class="h2"><h2><a class="selflink" name="section-11" href="#section-11">11</a>. Status Code Extensions to HTTP/1.1</h2></span> + + The following status codes are added to those defined in HTTP/1.1 + [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>]. + +<span class="h3"><h3><a class="selflink" name="section-11.1" href="#section-11.1">11.1</a>. 207 Multi-Status</h3></span> + + The 207 (Multi-Status) status code provides status for multiple + independent operations (see <a href="#section-13">Section 13</a> for more information). + +<span class="h3"><h3><a class="selflink" name="section-11.2" href="#section-11.2">11.2</a>. 422 Unprocessable Entity</h3></span> + + The 422 (Unprocessable Entity) status code means the server + understands the content type of the request entity (hence a + 415(Unsupported Media Type) status code is inappropriate), and the + syntax of the request entity is correct (thus a 400 (Bad Request) + status code is inappropriate) but was unable to process the contained + instructions. For example, this error condition may occur if an XML + request body contains well-formed (i.e., syntactically correct), but + semantically erroneous, XML instructions. + +<span class="h3"><h3><a class="selflink" name="section-11.3" href="#section-11.3">11.3</a>. 423 Locked</h3></span> + + The 423 (Locked) status code means the source or destination resource + of a method is locked. This response SHOULD contain an appropriate + precondition or postcondition code, such as 'lock-token-submitted' or + 'no-conflicting-lock'. + + + + + +<span class="grey">Dusseault Standards Track [Page 78]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-79" id="page-79" href="#page-79" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-11.4" href="#section-11.4">11.4</a>. 424 Failed Dependency</h3></span> + + The 424 (Failed Dependency) status code means that the method could + not be performed on the resource because the requested action + depended on another action and that action failed. For example, if a + command in a PROPPATCH method fails, then, at minimum, the rest of + the commands will also fail with 424 (Failed Dependency). + +<span class="h3"><h3><a class="selflink" name="section-11.5" href="#section-11.5">11.5</a>. 507 Insufficient Storage</h3></span> + + The 507 (Insufficient Storage) status code means the method could not + be performed on the resource because the server is unable to store + the representation needed to successfully complete the request. This + condition is considered to be temporary. If the request that + received this status code was the result of a user action, the + request MUST NOT be repeated until it is requested by a separate user + action. + +<span class="h2"><h2><a class="selflink" name="section-12" href="#section-12">12</a>. Use of HTTP Status Codes</h2></span> + + These HTTP codes are not redefined, but their use is somewhat + extended by WebDAV methods and requirements. In general, many HTTP + status codes can be used in response to any request, not just in + cases described in this document. Note also that WebDAV servers are + known to use 300-level redirect responses (and early interoperability + tests found clients unprepared to see those responses). A 300-level + response MUST NOT be used when the server has created a new resource + in response to the request. + +<span class="h3"><h3><a class="selflink" name="section-12.1" href="#section-12.1">12.1</a>. 412 Precondition Failed</h3></span> + + Any request can contain a conditional header defined in HTTP (If- + Match, If-Modified-Since, etc.) or the "If" or "Overwrite" + conditional headers defined in this specification. If the server + evaluates a conditional header, and if that condition fails to hold, + then this error code MUST be returned. On the other hand, if the + client did not include a conditional header in the request, then the + server MUST NOT use this status code. + +<span class="h3"><h3><a class="selflink" name="section-12.2" href="#section-12.2">12.2</a>. 414 Request-URI Too Long</h3></span> + + This status code is used in HTTP 1.1 only for Request-URIs, not URIs + in other locations. + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 79]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-80" id="page-80" href="#page-80" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="section-13" href="#section-13">13</a>. Multi-Status Response</h2></span> + + A Multi-Status response conveys information about multiple resources + in situations where multiple status codes might be appropriate. The + default Multi-Status response body is a text/xml or application/xml + HTTP entity with a 'multistatus' root element. Further elements + contain 200, 300, 400, and 500 series status codes generated during + the method invocation. 100 series status codes SHOULD NOT be recorded + in a 'response' XML element. + + Although '207' is used as the overall response status code, the + recipient needs to consult the contents of the multistatus response + body for further information about the success or failure of the + method execution. The response MAY be used in success, partial + success and also in failure situations. + + The 'multistatus' root element holds zero or more 'response' elements + in any order, each with information about an individual resource. + Each 'response' element MUST have an 'href' element to identify the + resource. + + A Multi-Status response uses one out of two distinct formats for + representing the status: + + 1. A 'status' element as child of the 'response' element indicates + the status of the message execution for the identified resource + as a whole (for instance, see <a href="#section-9.6.2">Section 9.6.2</a>). Some method + definitions provide information about specific status codes + clients should be prepared to see in a response. However, + clients MUST be able to handle other status codes, using the + generic rules defined in <a href="http://tools.ietf.org/html/rfc2616#section-10">Section 10 of [RFC2616]</a>. + + 2. For PROPFIND and PROPPATCH, the format has been extended using + the 'propstat' element instead of 'status', providing information + about individual properties of a resource. This format is + specific to PROPFIND and PROPPATCH, and is described in detail in + Sections <a href="#section-9.1">9.1</a> and <a href="#section-9.2">9.2</a>. + +<span class="h3"><h3><a class="selflink" name="section-13.1" href="#section-13.1">13.1</a>. Response Headers</h3></span> + + HTTP defines the Location header to indicate a preferred URL for the + resource that was addressed in the Request-URI (e.g., in response to + successful PUT requests or in redirect responses). However, use of + this header creates ambiguity when there are URLs in the body of the + response, as with Multi-Status. Thus, use of the Location header + with the Multi-Status response is intentionally undefined. + + + + + +<span class="grey">Dusseault Standards Track [Page 80]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-81" id="page-81" href="#page-81" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-13.2" href="#section-13.2">13.2</a>. Handling Redirected Child Resources</h3></span> + + Redirect responses (300-303, 305, and 307) defined in HTTP 1.1 + normally take a Location header to indicate the new URI for the + single resource redirected from the Request-URI. Multi-Status + responses contain many resource addresses, but the original + definition in [<a href="http://tools.ietf.org/html/rfc2518" title="" http extensions for distributed authoring webdav>RFC2518</a>] did not have any place for the server to + provide the new URI for redirected resources. This specification + does define a 'location' element for this information (see + <a href="#section-14.9">Section 14.9</a>). Servers MUST use this new element with redirect + responses in Multi-Status. + + Clients encountering redirected resources in Multi-Status MUST NOT + rely on the 'location' element being present with a new URI. If the + element is not present, the client MAY reissue the request to the + individual redirected resource, because the response to that request + can be redirected with a Location header containing the new URI. + +<span class="h3"><h3><a class="selflink" name="section-13.3" href="#section-13.3">13.3</a>. Internal Status Codes</h3></span> + + Sections <a href="#section-9.2.1">9.2.1</a>, <a href="#section-9.1.2">9.1.2</a>, <a href="#section-9.6.1">9.6.1</a>, <a href="#section-9.8.3">9.8.3</a>, and <a href="#section-9.9.2">9.9.2</a> define various status + codes used in Multi-Status responses. This specification does not + define the meaning of other status codes that could appear in these + responses. + +<span class="h2"><h2><a class="selflink" name="section-14" href="#section-14">14</a>. XML Element Definitions</h2></span> + + In this section, the final line of each section gives the element + type declaration using the format defined in [<a href="#ref-REC-XML" title="" extensible markup language edition>REC-XML</a>]. The "Value" + field, where present, specifies further restrictions on the allowable + contents of the XML element using BNF (i.e., to further restrict the + values of a PCDATA element). Note that all of the elements defined + here may be extended according to the rules defined in <a href="#section-17">Section 17</a>. + All elements defined here are in the "DAV:" namespace. + +<span class="h3"><h3><a class="selflink" name="section-14.1" href="#section-14.1">14.1</a>. activelock XML Element</h3></span> + + Name: activelock + + Purpose: Describes a lock on a resource. + + + <!ELEMENT activelock (lockscope, locktype, depth, owner?, timeout?, + locktoken?, lockroot)> + + + + + + + +<span class="grey">Dusseault Standards Track [Page 81]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-82" id="page-82" href="#page-82" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-14.2" href="#section-14.2">14.2</a>. allprop XML Element</h3></span> + + Name: allprop + + Purpose: Specifies that all names and values of dead properties and + the live properties defined by this document existing on the + resource are to be returned. + + <!ELEMENT allprop EMPTY > + +<span class="h3"><h3><a class="selflink" name="section-14.3" href="#section-14.3">14.3</a>. collection XML Element</h3></span> + + Name: collection + + Purpose: Identifies the associated resource as a collection. The + DAV:resourcetype property of a collection resource MUST contain + this element. It is normally empty but extensions may add sub- + elements. + + <!ELEMENT collection EMPTY > + +<span class="h3"><h3><a class="selflink" name="section-14.4" href="#section-14.4">14.4</a>. depth XML Element</h3></span> + + Name: depth + + Purpose: Used for representing depth values in XML content (e.g., + in lock information). + + Value: "0" | "1" | "infinity" + + <!ELEMENT depth (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-14.5" href="#section-14.5">14.5</a>. error XML Element</h3></span> + + Name: error + + Purpose: Error responses, particularly 403 Forbidden and 409 + Conflict, sometimes need more information to indicate what went + wrong. In these cases, servers MAY return an XML response body + with a document element of 'error', containing child elements + identifying particular condition codes. + + Description: Contains at least one XML element, and MUST NOT + contain text or mixed content. Any element that is a child of the + 'error' element is considered to be a precondition or + postcondition code. Unrecognized elements MUST be ignored. + + <!ELEMENT error ANY > + + + +<span class="grey">Dusseault Standards Track [Page 82]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-83" id="page-83" href="#page-83" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-14.6" href="#section-14.6">14.6</a>. exclusive XML Element</h3></span> + + Name: exclusive + + Purpose: Specifies an exclusive lock. + + + <!ELEMENT exclusive EMPTY > + + +<span class="h3"><h3><a class="selflink" name="section-14.7" href="#section-14.7">14.7</a>. href XML Element</h3></span> + + Name: href + + Purpose: MUST contain a URI or a relative reference. + + Description: There may be limits on the value of 'href' depending + on the context of its use. Refer to the specification text where + 'href' is used to see what limitations apply in each case. + + Value: Simple-ref + + + <!ELEMENT href (#PCDATA)> + +<span class="h3"><h3><a class="selflink" name="section-14.8" href="#section-14.8">14.8</a>. include XML Element</h3></span> + + Name: include + + Purpose: Any child element represents the name of a property to be + included in the PROPFIND response. All elements inside an + 'include' XML element MUST define properties related to the + resource, although possible property names are in no way limited + to those property names defined in this document or other + standards. This element MUST NOT contain text or mixed content. + + <!ELEMENT include ANY > + +<span class="h3"><h3><a class="selflink" name="section-14.9" href="#section-14.9">14.9</a>. location XML Element</h3></span> + + Name: location + + Purpose: HTTP defines the "Location" header (see [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>], <a href="#section-14.30">Section</a> + <a href="#section-14.30">14.30</a>) for use with some status codes (such as 201 and the 300 + series codes). When these codes are used inside a 'multistatus' + element, the 'location' element can be used to provide the + accompanying Location header value. + + + + +<span class="grey">Dusseault Standards Track [Page 83]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-84" id="page-84" href="#page-84" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Description: Contains a single href element with the same value + that would be used in a Location header. + + + <!ELEMENT location (href)> + +<span class="h3"><h3><a class="selflink" name="section-14.10" href="#section-14.10">14.10</a>. lockentry XML Element</h3></span> + + Name: lockentry + + Purpose: Defines the types of locks that can be used with the + resource. + + <!ELEMENT lockentry (lockscope, locktype) > + +<span class="h3"><h3><a class="selflink" name="section-14.11" href="#section-14.11">14.11</a>. lockinfo XML Element</h3></span> + + Name: lockinfo + + Purpose: The 'lockinfo' XML element is used with a LOCK method to + specify the type of lock the client wishes to have created. + + + <!ELEMENT lockinfo (lockscope, locktype, owner?) > + +<span class="h3"><h3><a class="selflink" name="section-14.12" href="#section-14.12">14.12</a>. lockroot XML Element</h3></span> + + Name: lockroot + + Purpose: Contains the root URL of the lock, which is the URL + through which the resource was addressed in the LOCK request. + + Description: The href element contains the root of the lock. The + server SHOULD include this in all DAV:lockdiscovery property + values and the response to LOCK requests. + + <!ELEMENT lockroot (href) > + +<span class="h3"><h3><a class="selflink" name="section-14.13" href="#section-14.13">14.13</a>. lockscope XML Element</h3></span> + + Name: lockscope + + Purpose: Specifies whether a lock is an exclusive lock, or a shared + lock. + + + <!ELEMENT lockscope (exclusive | shared) > + + + + +<span class="grey">Dusseault Standards Track [Page 84]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-85" id="page-85" href="#page-85" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-14.14" href="#section-14.14">14.14</a>. locktoken XML Element</h3></span> + + Name: locktoken + + Purpose: The lock token associated with a lock. + + Description: The href contains a single lock token URI, which + refers to the lock. + + <!ELEMENT locktoken (href) > + +<span class="h3"><h3><a class="selflink" name="section-14.15" href="#section-14.15">14.15</a>. locktype XML Element</h3></span> + + Name: locktype + + Purpose: Specifies the access type of a lock. At present, this + specification only defines one lock type, the write lock. + + + <!ELEMENT locktype (write) > + + +<span class="h3"><h3><a class="selflink" name="section-14.16" href="#section-14.16">14.16</a>. multistatus XML Element</h3></span> + + Name: multistatus + + Purpose: Contains multiple response messages. + + Description: The 'responsedescription' element at the top level is + used to provide a general message describing the overarching + nature of the response. If this value is available, an + application may use it instead of presenting the individual + response descriptions contained within the responses. + + + <!ELEMENT multistatus (response*, responsedescription?) > + + +<span class="h3"><h3><a class="selflink" name="section-14.17" href="#section-14.17">14.17</a>. owner XML Element</h3></span> + + Name: owner + + Purpose: Holds client-supplied information about the creator of a + lock. + + Description: Allows a client to provide information sufficient for + either directly contacting a principal (such as a telephone number + or Email URI), or for discovering the principal (such as the URL + + + +<span class="grey">Dusseault Standards Track [Page 85]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-86" id="page-86" href="#page-86" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + of a homepage) who created a lock. The value provided MUST be + treated as a dead property in terms of XML Information Item + preservation. The server MUST NOT alter the value unless the + owner value provided by the client is empty. For a certain amount + of interoperability between different client implementations, if + clients have URI-formatted contact information for the lock + creator suitable for user display, then clients SHOULD put those + URIs in 'href' child elements of the 'owner' element. + + Extensibility: MAY be extended with child elements, mixed content, + text content or attributes. + + <!ELEMENT owner ANY > + +<span class="h3"><h3><a class="selflink" name="section-14.18" href="#section-14.18">14.18</a>. prop XML Element</h3></span> + + Name: prop + + Purpose: Contains properties related to a resource. + + Description: A generic container for properties defined on + resources. All elements inside a 'prop' XML element MUST define + properties related to the resource, although possible property + names are in no way limited to those property names defined in + this document or other standards. This element MUST NOT contain + text or mixed content. + + <!ELEMENT prop ANY > + +<span class="h3"><h3><a class="selflink" name="section-14.19" href="#section-14.19">14.19</a>. propertyupdate XML Element</h3></span> + + Name: propertyupdate + + Purpose: Contains a request to alter the properties on a resource. + + Description: This XML element is a container for the information + required to modify the properties on the resource. + + <!ELEMENT propertyupdate (remove | set)+ > + +<span class="h3"><h3><a class="selflink" name="section-14.20" href="#section-14.20">14.20</a>. propfind XML Element</h3></span> + + Name: propfind + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 86]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-87" id="page-87" href="#page-87" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Purpose: Specifies the properties to be returned from a PROPFIND + method. Four special elements are specified for use with + 'propfind': 'prop', 'allprop', 'include', and 'propname'. If + 'prop' is used inside 'propfind', it MUST NOT contain property + values. + + <!ELEMENT propfind ( propname | (allprop, include?) | prop ) > + +<span class="h3"><h3><a class="selflink" name="section-14.21" href="#section-14.21">14.21</a>. propname XML Element</h3></span> + + Name: propname + + Purpose: Specifies that only a list of property names on the + resource is to be returned. + + <!ELEMENT propname EMPTY > + +<span class="h3"><h3><a class="selflink" name="section-14.22" href="#section-14.22">14.22</a>. propstat XML Element</h3></span> + + Name: propstat + + Purpose: Groups together a prop and status element that is + associated with a particular 'href' element. + + Description: The propstat XML element MUST contain one prop XML + element and one status XML element. The contents of the prop XML + element MUST only list the names of properties to which the result + in the status element applies. The optional precondition/ + postcondition element and 'responsedescription' text also apply to + the properties named in 'prop'. + + <!ELEMENT propstat (prop, status, error?, responsedescription?) > + +<span class="h3"><h3><a class="selflink" name="section-14.23" href="#section-14.23">14.23</a>. remove XML Element</h3></span> + + Name: remove + + Purpose: Lists the properties to be removed from a resource. + + Description: Remove instructs that the properties specified in prop + should be removed. Specifying the removal of a property that does + not exist is not an error. All the XML elements in a 'prop' XML + element inside of a 'remove' XML element MUST be empty, as only + the names of properties to be removed are required. + + <!ELEMENT remove (prop) > + + + + + +<span class="grey">Dusseault Standards Track [Page 87]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-88" id="page-88" href="#page-88" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h3"><h3><a class="selflink" name="section-14.24" href="#section-14.24">14.24</a>. response XML Element</h3></span> + + Name: response + + Purpose: Holds a single response describing the effect of a method + on resource and/or its properties. + + Description: The 'href' element contains an HTTP URL pointing to a + WebDAV resource when used in the 'response' container. A + particular 'href' value MUST NOT appear more than once as the + child of a 'response' XML element under a 'multistatus' XML + element. This requirement is necessary in order to keep + processing costs for a response to linear time. Essentially, this + prevents having to search in order to group together all the + responses by 'href'. There are, however, no requirements + regarding ordering based on 'href' values. The optional + precondition/postcondition element and 'responsedescription' text + can provide additional information about this resource relative to + the request or result. + + + <!ELEMENT response (href, ((href*, status)|(propstat+)), + error?, responsedescription? , location?) > + +<span class="h3"><h3><a class="selflink" name="section-14.25" href="#section-14.25">14.25</a>. responsedescription XML Element</h3></span> + + Name: responsedescription + + Purpose: Contains information about a status response within a + Multi-Status. + + Description: Provides information suitable to be presented to a + user. + + <!ELEMENT responsedescription (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-14.26" href="#section-14.26">14.26</a>. set XML Element</h3></span> + + Name: set + + Purpose: Lists the property values to be set for a resource. + + Description: The 'set' element MUST contain only a 'prop' element. + The elements contained by the 'prop' element inside the 'set' + element MUST specify the name and value of properties that are set + on the resource identified by Request-URI. If a property already + exists, then its value is replaced. Language tagging information + appearing in the scope of the 'prop' element (in the "xml:lang" + + + +<span class="grey">Dusseault Standards Track [Page 88]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-89" id="page-89" href="#page-89" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + attribute, if present) MUST be persistently stored along with the + property, and MUST be subsequently retrievable using PROPFIND. + + <!ELEMENT set (prop) > + +<span class="h3"><h3><a class="selflink" name="section-14.27" href="#section-14.27">14.27</a>. shared XML Element</h3></span> + + Name: shared + + Purpose: Specifies a shared lock. + + + <!ELEMENT shared EMPTY > + + +<span class="h3"><h3><a class="selflink" name="section-14.28" href="#section-14.28">14.28</a>. status XML Element</h3></span> + + Name: status + + Purpose: Holds a single HTTP status-line. + + Value: status-line (defined in <a href="http://tools.ietf.org/html/rfc2616#section-6.1">Section 6.1 of [RFC2616]</a>) + + <!ELEMENT status (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-14.29" href="#section-14.29">14.29</a>. timeout XML Element</h3></span> + + Name: timeout + + Purpose: The number of seconds remaining before a lock expires. + + Value: TimeType (defined in <a href="#section-10.7">Section 10.7</a>) + + + <!ELEMENT timeout (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-14.30" href="#section-14.30">14.30</a>. write XML Element</h3></span> + + Name: write + + Purpose: Specifies a write lock. + + + <!ELEMENT write EMPTY > + + + + + + + +<span class="grey">Dusseault Standards Track [Page 89]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-90" id="page-90" href="#page-90" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="section-15" href="#section-15">15</a>. DAV Properties</h2></span> + + For DAV properties, the name of the property is also the same as the + name of the XML element that contains its value. In the section + below, the final line of each section gives the element type + declaration using the format defined in [<a href="#ref-REC-XML" title="" extensible markup language edition>REC-XML</a>]. The "Value" + field, where present, specifies further restrictions on the allowable + contents of the XML element using BNF (i.e., to further restrict the + values of a PCDATA element). + + A protected property is one that cannot be changed with a PROPPATCH + request. There may be other requests that would result in a change + to a protected property (as when a LOCK request affects the value of + DAV:lockdiscovery). Note that a given property could be protected on + one type of resource, but not protected on another type of resource. + + A computed property is one with a value defined in terms of a + computation (based on the content and other properties of that + resource, or even of some other resource). A computed property is + always a protected property. + + COPY and MOVE behavior refers to local COPY and MOVE operations. + + For properties defined based on HTTP GET response headers (DAV:get*), + the header value could include LWS as defined in [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>], <a href="#section-4.2">Section</a> + <a href="#section-4.2">4.2</a>. Server implementors SHOULD strip LWS from these values before + using as WebDAV property values. + +<span class="h3"><h3><a class="selflink" name="section-15.1" href="#section-15.1">15.1</a>. creationdate Property</h3></span> + + Name: creationdate + + Purpose: Records the time and date the resource was created. + + Value: date-time (defined in [<a href="http://tools.ietf.org/html/rfc3339" title="" date and time on the internet: timestamps>RFC3339</a>], see the ABNF in <a href="#section-5.6">Section</a> + <a href="#section-5.6">5.6</a>.) + + Protected: MAY be protected. Some servers allow DAV:creationdate + to be changed to reflect the time the document was created if that + is more meaningful to the user (rather than the time it was + uploaded). Thus, clients SHOULD NOT use this property in + synchronization logic (use DAV:getetag instead). + + COPY/MOVE behavior: This property value SHOULD be kept during a + MOVE operation, but is normally re-initialized when a resource is + created with a COPY. It should not be set in a COPY. + + + + + +<span class="grey">Dusseault Standards Track [Page 90]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-91" id="page-91" href="#page-91" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Description: The DAV:creationdate property SHOULD be defined on all + DAV compliant resources. If present, it contains a timestamp of + the moment when the resource was created. Servers that are + incapable of persistently recording the creation date SHOULD + instead leave it undefined (i.e. report "Not Found"). + + <!ELEMENT creationdate (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-15.2" href="#section-15.2">15.2</a>. displayname Property</h3></span> + + Name: displayname + + Purpose: Provides a name for the resource that is suitable for + presentation to a user. + + Value: Any text. + + Protected: SHOULD NOT be protected. Note that servers implementing + [<a href="http://tools.ietf.org/html/rfc2518" title="" http extensions for distributed authoring webdav>RFC2518</a>] might have made this a protected property as this is a + new requirement. + + COPY/MOVE behavior: This property value SHOULD be preserved in COPY + and MOVE operations. + + Description: Contains a description of the resource that is + suitable for presentation to a user. This property is defined on + the resource, and hence SHOULD have the same value independent of + the Request-URI used to retrieve it (thus, computing this property + based on the Request-URI is deprecated). While generic clients + might display the property value to end users, client UI designers + must understand that the method for identifying resources is still + the URL. Changes to DAV:displayname do not issue moves or copies + to the server, but simply change a piece of meta-data on the + individual resource. Two resources can have the same DAV: + displayname value even within the same collection. + + <!ELEMENT displayname (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-15.3" href="#section-15.3">15.3</a>. getcontentlanguage Property</h3></span> + + Name: getcontentlanguage + + Purpose: Contains the Content-Language header value (from <a href="#section-14.12">Section</a> + <a href="#section-14.12">14.12</a> of [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>]) as it would be returned by a GET without + accept headers. + + Value: language-tag (language-tag is defined in <a href="http://tools.ietf.org/html/rfc2616#section-3.10">Section 3.10 of + [RFC2616]</a>) + + + +<span class="grey">Dusseault Standards Track [Page 91]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-92" id="page-92" href="#page-92" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Protected: SHOULD NOT be protected, so that clients can reset the + language. Note that servers implementing [<a href="http://tools.ietf.org/html/rfc2518" title="" http extensions for distributed authoring webdav>RFC2518</a>] might have + made this a protected property as this is a new requirement. + + COPY/MOVE behavior: This property value SHOULD be preserved in COPY + and MOVE operations. + + Description: The DAV:getcontentlanguage property MUST be defined on + any DAV-compliant resource that returns the Content-Language + header on a GET. + + <!ELEMENT getcontentlanguage (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-15.4" href="#section-15.4">15.4</a>. getcontentlength Property</h3></span> + + Name: getcontentlength + + Purpose: Contains the Content-Length header returned by a GET + without accept headers. + + Value: See <a href="http://tools.ietf.org/html/rfc2616#section-14.13">Section 14.13 of [RFC2616]</a>. + + Protected: This property is computed, therefore protected. + + Description: The DAV:getcontentlength property MUST be defined on + any DAV-compliant resource that returns the Content-Length header + in response to a GET. + + COPY/MOVE behavior: This property value is dependent on the size of + the destination resource, not the value of the property on the + source resource. + + <!ELEMENT getcontentlength (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-15.5" href="#section-15.5">15.5</a>. getcontenttype Property</h3></span> + + Name: getcontenttype + + Purpose: Contains the Content-Type header value (from <a href="http://tools.ietf.org/html/rfc2616#section-14.17">Section 14.17 + of [RFC2616]</a>) as it would be returned by a GET without accept + headers. + + Value: media-type (defined in <a href="http://tools.ietf.org/html/rfc2616#section-3.7">Section 3.7 of [RFC2616]</a>) + + Protected: Potentially protected if the server prefers to assign + content types on its own (see also discussion in <a href="#section-9.7.1">Section 9.7.1</a>). + + + + + +<span class="grey">Dusseault Standards Track [Page 92]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-93" id="page-93" href="#page-93" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + COPY/MOVE behavior: This property value SHOULD be preserved in COPY + and MOVE operations. + + Description: This property MUST be defined on any DAV-compliant + resource that returns the Content-Type header in response to a + GET. + + <!ELEMENT getcontenttype (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-15.6" href="#section-15.6">15.6</a>. getetag Property</h3></span> + + Name: getetag + + Purpose: Contains the ETag header value (from <a href="http://tools.ietf.org/html/rfc2616#section-14.19">Section 14.19 of + [RFC2616]</a>) as it would be returned by a GET without accept + headers. + + Value: entity-tag (defined in <a href="http://tools.ietf.org/html/rfc2616#section-3.11">Section 3.11 of [RFC2616]</a>) + + Protected: MUST be protected because this value is created and + controlled by the server. + + COPY/MOVE behavior: This property value is dependent on the final + state of the destination resource, not the value of the property + on the source resource. Also note the considerations in + <a href="#section-8.8">Section 8.8</a>. + + Description: The getetag property MUST be defined on any DAV- + compliant resource that returns the Etag header. Refer to <a href="#section-3.11">Section</a> + <a href="#section-3.11">3.11</a> of <a href="http://tools.ietf.org/html/rfc2616">RFC 2616</a> for a complete definition of the semantics of an + ETag, and to <a href="#section-8.6">Section 8.6</a> for a discussion of ETags in WebDAV. + + <!ELEMENT getetag (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-15.7" href="#section-15.7">15.7</a>. getlastmodified Property</h3></span> + + Name: getlastmodified + + Purpose: Contains the Last-Modified header value (from <a href="#section-14.29">Section</a> + <a href="#section-14.29">14.29</a> of [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>]) as it would be returned by a GET method + without accept headers. + + Value: <a href="http://tools.ietf.org/html/rfc1123">rfc1123</a>-date (defined in <a href="http://tools.ietf.org/html/rfc2616#section-3.3.1">Section 3.3.1 of [RFC2616]</a>) + + Protected: SHOULD be protected because some clients may rely on the + value for appropriate caching behavior, or on the value of the + Last-Modified header to which this property is linked. + + + + +<span class="grey">Dusseault Standards Track [Page 93]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-94" id="page-94" href="#page-94" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + COPY/MOVE behavior: This property value is dependent on the last + modified date of the destination resource, not the value of the + property on the source resource. Note that some server + implementations use the file system date modified value for the + DAV:getlastmodified value, and this can be preserved in a MOVE + even when the HTTP Last-Modified value SHOULD change. Note that + since [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>] requires clients to use ETags where provided, a + server implementing ETags can count on clients using a much better + mechanism than modification dates for offline synchronization or + cache control. Also note the considerations in <a href="#section-8.8">Section 8.8</a>. + + Description: The last-modified date on a resource SHOULD only + reflect changes in the body (the GET responses) of the resource. + A change in a property only SHOULD NOT cause the last-modified + date to change, because clients MAY rely on the last-modified date + to know when to overwrite the existing body. The DAV: + getlastmodified property MUST be defined on any DAV-compliant + resource that returns the Last-Modified header in response to a + GET. + + <!ELEMENT getlastmodified (#PCDATA) > + +<span class="h3"><h3><a class="selflink" name="section-15.8" href="#section-15.8">15.8</a>. lockdiscovery Property</h3></span> + + Name: lockdiscovery + + Purpose: Describes the active locks on a resource + + Protected: MUST be protected. Clients change the list of locks + through LOCK and UNLOCK, not through PROPPATCH. + + COPY/MOVE behavior: The value of this property depends on the lock + state of the destination, not on the locks of the source resource. + Recall that locks are not moved in a MOVE operation. + + Description: Returns a listing of who has a lock, what type of lock + he has, the timeout type and the time remaining on the timeout, + and the associated lock token. Owner information MAY be omitted + if it is considered sensitive. If there are no locks, but the + server supports locks, the property will be present but contain + zero 'activelock' elements. If there are one or more locks, an + 'activelock' element appears for each lock on the resource. This + property is NOT lockable with respect to write locks (<a href="#section-7">Section 7</a>). + + <!ELEMENT lockdiscovery (activelock)* > + + + + + + +<span class="grey">Dusseault Standards Track [Page 94]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-95" id="page-95" href="#page-95" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h4"><h4><a class="selflink" name="section-15.8.1" href="#section-15.8.1">15.8.1</a>. Example - Retrieving DAV:lockdiscovery</h4></span> + + >>Request + + PROPFIND /container/ HTTP/1.1 + Host: www.example.com + Content-Length: xxxx + Content-Type: application/xml; charset="utf-8" + + <?xml version="1.0" encoding="utf-8" ?> + <D:propfind xmlns:D='DAV:'> + <D:prop><D:lockdiscovery/></D:prop> + </D:propfind> + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:multistatus xmlns:D='DAV:'> + <D:response> + <D:href>http://www.example.com/container/</D:href> + <D:propstat> + <D:prop> + <D:lockdiscovery> + <D:activelock> + <D:locktype><D:write/></D:locktype> + <D:lockscope><D:exclusive/></D:lockscope> + <D:depth>0</D:depth> + <D:owner>Jane Smith</D:owner> + <D:timeout>Infinite</D:timeout> + <D:locktoken> + <D:href + >urn:uuid:f81de2ad-7f3d-a1b2-4f3c-00a0c91a9d76</D:href> + </D:locktoken> + <D:lockroot> + <D:href>http://www.example.com/container/</D:href> + </D:lockroot> + </D:activelock> + </D:lockdiscovery> + </D:prop> + <D:status>HTTP/1.1 200 OK</D:status> + </D:propstat> + </D:response> + </D:multistatus> + + + + +<span class="grey">Dusseault Standards Track [Page 95]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-96" id="page-96" href="#page-96" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + This resource has a single exclusive write lock on it, with an + infinite timeout. + +<span class="h3"><h3><a class="selflink" name="section-15.9" href="#section-15.9">15.9</a>. resourcetype Property</h3></span> + + Name: resourcetype + + Purpose: Specifies the nature of the resource. + + Protected: SHOULD be protected. Resource type is generally decided + through the operation creating the resource (MKCOL vs PUT), not by + PROPPATCH. + + COPY/MOVE behavior: Generally a COPY/MOVE of a resource results in + the same type of resource at the destination. + + Description: MUST be defined on all DAV-compliant resources. Each + child element identifies a specific type the resource belongs to, + such as 'collection', which is the only resource type defined by + this specification (see <a href="#section-14.3">Section 14.3</a>). If the element contains + the 'collection' child element plus additional unrecognized + elements, it should generally be treated as a collection. If the + element contains no recognized child elements, it should be + treated as a non-collection resource. The default value is empty. + This element MUST NOT contain text or mixed content. Any custom + child element is considered to be an identifier for a resource + type. + + Example: (fictional example to show extensibility) + + <x:resourcetype xmlns:x="DAV:"> + <x:collection/> + <f:search-results xmlns:f="http://www.example.com/ns"/> + </x:resourcetype> + +<span class="h3"><h3><a class="selflink" name="section-15.10" href="#section-15.10">15.10</a>. supportedlock Property</h3></span> + + Name: supportedlock + + Purpose: To provide a listing of the lock capabilities supported by + the resource. + + Protected: MUST be protected. Servers, not clients, determine what + lock mechanisms are supported. + + + + + + + +<span class="grey">Dusseault Standards Track [Page 96]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-97" id="page-97" href="#page-97" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + COPY/MOVE behavior: This property value is dependent on the kind of + locks supported at the destination, not on the value of the + property at the source resource. Servers attempting to COPY to a + destination should not attempt to set this property at the + destination. + + Description: Returns a listing of the combinations of scope and + access types that may be specified in a lock request on the + resource. Note that the actual contents are themselves controlled + by access controls, so a server is not required to provide + information the client is not authorized to see. This property is + NOT lockable with respect to write locks (<a href="#section-7">Section 7</a>). + + <!ELEMENT supportedlock (lockentry)* > + +<span class="h4"><h4><a class="selflink" name="section-15.10.1" href="#section-15.10.1">15.10.1</a>. Example - Retrieving DAV:supportedlock</h4></span> + + >>Request + + PROPFIND /container/ HTTP/1.1 + Host: www.example.com + Content-Length: xxxx + Content-Type: application/xml; charset="utf-8" + + <?xml version="1.0" encoding="utf-8" ?> + <D:propfind xmlns:D="DAV:"> + <D:prop><D:supportedlock/></D:prop> + </D:propfind> + + >>Response + + HTTP/1.1 207 Multi-Status + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:multistatus xmlns:D="DAV:"> + <D:response> + <D:href>http://www.example.com/container/</D:href> + <D:propstat> + <D:prop> + <D:supportedlock> + <D:lockentry> + <D:lockscope><D:exclusive/></D:lockscope> + <D:locktype><D:write/></D:locktype> + </D:lockentry> + <D:lockentry> + <D:lockscope><D:shared/></D:lockscope> + + + +<span class="grey">Dusseault Standards Track [Page 97]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-98" id="page-98" href="#page-98" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + <D:locktype><D:write/></D:locktype> + </D:lockentry> + </D:supportedlock> + </D:prop> + <D:status>HTTP/1.1 200 OK</D:status> + </D:propstat> + </D:response> + </D:multistatus> + +<span class="h2"><h2><a class="selflink" name="section-16" href="#section-16">16</a>. Precondition/Postcondition XML Elements</h2></span> + + As introduced in <a href="#section-8.7">Section 8.7</a>, extra information on error conditions + can be included in the body of many status responses. This section + makes requirements on the use of the error body mechanism and + introduces a number of precondition and postcondition codes. + + A "precondition" of a method describes the state of the server that + must be true for that method to be performed. A "postcondition" of a + method describes the state of the server that must be true after that + method has been completed. + + Each precondition and postcondition has a unique XML element + associated with it. In a 207 Multi-Status response, the XML element + MUST appear inside an 'error' element in the appropriate 'propstat or + 'response' element depending on whether the condition applies to one + or more properties or to the resource as a whole. In all other error + responses where this specification's 'error' body is used, the + precondition/postcondition XML element MUST be returned as the child + of a top-level 'error' element in the response body, unless otherwise + negotiated by the request, along with an appropriate response status. + The most common response status codes are 403 (Forbidden) if the + request should not be repeated because it will always fail, and 409 + (Conflict) if it is expected that the user might be able to resolve + the conflict and resubmit the request. The 'error' element MAY + contain child elements with specific error information and MAY be + extended with any custom child elements. + + This mechanism does not take the place of using a correct numeric + status code as defined here or in HTTP, because the client must + always be able to take a reasonable course of action based only on + the numeric code. However, it does remove the need to define new + numeric codes. The new machine-readable codes used for this purpose + are XML elements classified as preconditions and postconditions, so + naturally, any group defining a new condition code can use their own + namespace. As always, the "DAV:" namespace is reserved for use by + IETF-chartered WebDAV working groups. + + + + + +<span class="grey">Dusseault Standards Track [Page 98]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-99" id="page-99" href="#page-99" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + A server supporting this specification SHOULD use the XML error + whenever a precondition or postcondition defined in this document is + violated. For error conditions not specified in this document, the + server MAY simply choose an appropriate numeric status and leave the + response body blank. However, a server MAY instead use a custom + condition code and other supporting text, because even when clients + do not automatically recognize condition codes, they can be quite + useful in interoperability testing and debugging. + + Example - Response with precondition code + + >>Response + + HTTP/1.1 423 Locked + Content-Type: application/xml; charset="utf-8" + Content-Length: xxxx + + <?xml version="1.0" encoding="utf-8" ?> + <D:error xmlns:D="DAV:"> + <D:lock-token-submitted> + <D:href>/workspace/webdav/</D:href> + </D:lock-token-submitted> + </D:error> + + In this example, a client unaware of a depth-infinity lock on the + parent collection "/workspace/webdav/" attempted to modify the + collection member "/workspace/webdav/proposal.doc". + + Some other useful preconditions and postconditions have been defined + in other specifications extending WebDAV, such as [<a href="http://tools.ietf.org/html/rfc3744" title="" web distributed authoring and versioning access control protocol>RFC3744</a>] (see + particularly <a href="#section-7.1.1">Section 7.1.1</a>), [<a href="http://tools.ietf.org/html/rfc3253" title="" versioning extensions to webdav distributed authoring and>RFC3253</a>], and [<a href="http://tools.ietf.org/html/rfc3648" title="" web distributed authoring and versioning ordered collections protocol>RFC3648</a>]. + + All these elements are in the "DAV:" namespace. If not specified + otherwise, the content for each condition's XML element is defined to + be empty. + + + Name: lock-token-matches-request-uri + + Use with: 409 Conflict + + Purpose: (precondition) -- A request may include a Lock-Token header + to identify a lock for the UNLOCK method. However, if the + Request-URI does not fall within the scope of the lock identified + by the token, the server SHOULD use this error. The lock may have + a scope that does not include the Request-URI, or the lock could + have disappeared, or the token may be invalid. + + + + +<span class="grey">Dusseault Standards Track [Page 99]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-100" id="page-100" href="#page-100" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Name: lock-token-submitted (precondition) + + Use with: 423 Locked + + Purpose: The request could not succeed because a lock token should + have been submitted. This element, if present, MUST contain at + least one URL of a locked resource that prevented the request. In + cases of MOVE, COPY, and DELETE where collection locks are + involved, it can be difficult for the client to find out which + locked resource made the request fail -- but the server is only + responsible for returning one such locked resource. The server + MAY return every locked resource that prevented the request from + succeeding if it knows them all. + + <!ELEMENT lock-token-submitted (href+) > + + + Name: no-conflicting-lock (precondition) + + Use with: Typically 423 Locked + + Purpose: A LOCK request failed due the presence of an already + existing conflicting lock. Note that a lock can be in conflict + although the resource to which the request was directed is only + indirectly locked. In this case, the precondition code can be + used to inform the client about the resource that is the root of + the conflicting lock, avoiding a separate lookup of the + "lockdiscovery" property. + + <!ELEMENT no-conflicting-lock (href)* > + + + Name: no-external-entities + + Use with: 403 Forbidden + + Purpose: (precondition) -- If the server rejects a client request + because the request body contains an external entity, the server + SHOULD use this error. + + + Name: preserved-live-properties + + Use with: 409 Conflict + + Purpose: (postcondition) -- The server received an otherwise-valid + MOVE or COPY request, but cannot maintain the live properties with + the same behavior at the destination. It may be that the server + + + +<span class="grey">Dusseault Standards Track [Page 100]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-101" id="page-101" href="#page-101" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + only supports some live properties in some parts of the + repository, or simply has an internal error. + + + Name: propfind-finite-depth + + Use with: 403 Forbidden + + Purpose: (precondition) -- This server does not allow infinite-depth + PROPFIND requests on collections. + + + Name: cannot-modify-protected-property + + Use with: 403 Forbidden + + Purpose: (precondition) -- The client attempted to set a protected + property in a PROPPATCH (such as DAV:getetag). See also + <a href="http://tools.ietf.org/html/rfc3253#section-3.12">[RFC3253], Section 3.12</a>. + +<span class="h2"><h2><a class="selflink" name="section-17" href="#section-17">17</a>. XML Extensibility in DAV</h2></span> + + The XML namespace extension ([<a href="#ref-REC-XML-NAMES" title="" namespaces in xml edition>REC-XML-NAMES</a>]) is used in this + specification in order to allow for new XML elements to be added + without fear of colliding with other element names. Although WebDAV + request and response bodies can be extended by arbitrary XML + elements, which can be ignored by the message recipient, an XML + element in the "DAV:" namespace SHOULD NOT be used in the request or + response body unless that XML element is explicitly defined in an + IETF RFC reviewed by a WebDAV working group. + + For WebDAV to be both extensible and backwards-compatible, both + clients and servers need to know how to behave when unexpected or + unrecognized command extensions are received. For XML processing, + this means that clients and servers MUST process received XML + documents as if unexpected elements and attributes (and all children + of unrecognized elements) were not there. An unexpected element or + attribute includes one that may be used in another context but is not + expected here. Ignoring such items for purposes of processing can of + course be consistent with logging all information or presenting for + debugging. + + This restriction also applies to the processing, by clients, of DAV + property values where unexpected XML elements SHOULD be ignored + unless the property's schema declares otherwise. + + This restriction does not apply to setting dead DAV properties on the + server where the server MUST record all XML elements. + + + +<span class="grey">Dusseault Standards Track [Page 101]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-102" id="page-102" href="#page-102" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Additionally, this restriction does not apply to the use of XML where + XML happens to be the content type of the entity body, for example, + when used as the body of a PUT. + + Processing instructions in XML SHOULD be ignored by recipients. + Thus, specifications extending WebDAV SHOULD NOT use processing + instructions to define normative behavior. + + XML DTD fragments are included for all the XML elements defined in + this specification. However, correct XML will not be valid according + to any DTD due to namespace usage and extension rules. In + particular: + + o Elements (from this specification) are in the "DAV:" namespace, + + o Element ordering is irrelevant unless otherwise stated, + + o Extension attributes MAY be added, + + o For element type definitions of "ANY", the normative text + definition for that element defines what can be in it and what + that means. + + o For element type definitions of "#PCDATA", extension elements MUST + NOT be added. + + o For other element type definitions, including "EMPTY", extension + elements MAY be added. + + Note that this means that elements containing elements cannot be + extended to contain text, and vice versa. + + With DTD validation relaxed by the rules above, the constraints + described by the DTD fragments are normative (see for example + <a href="#appendix-A">Appendix A</a>). A recipient of a WebDAV message with an XML body MUST + NOT validate the XML document according to any hard-coded or + dynamically-declared DTD. + + Note that this section describes backwards-compatible extensibility + rules. There might also be times when an extension is designed not + to be backwards-compatible, for example, defining an extension that + reuses an XML element defined in this document but omitting one of + the child elements required by the DTDs in this specification. + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 102]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-103" id="page-103" href="#page-103" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="section-18" href="#section-18">18</a>. DAV Compliance Classes</h2></span> + + A DAV-compliant resource can advertise several classes of compliance. + A client can discover the compliance classes of a resource by + executing OPTIONS on the resource and examining the "DAV" header + which is returned. Note particularly that resources, rather than + servers, are spoken of as being compliant. That is because + theoretically some resources on a server could support different + feature sets. For example, a server could have a sub-repository + where an advanced feature like versioning was supported, even if that + feature was not supported on all sub-repositories. + + Since this document describes extensions to the HTTP/1.1 protocol, + minimally all DAV-compliant resources, clients, and proxies MUST be + compliant with [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>]. + + A resource that is class 2 or class 3 compliant must also be class 1 + compliant. + +<span class="h3"><h3><a class="selflink" name="section-18.1" href="#section-18.1">18.1</a>. Class 1</h3></span> + + A class 1 compliant resource MUST meet all "MUST" requirements in all + sections of this document. + + Class 1 compliant resources MUST return, at minimum, the value "1" in + the DAV header on all responses to the OPTIONS method. + +<span class="h3"><h3><a class="selflink" name="section-18.2" href="#section-18.2">18.2</a>. Class 2</h3></span> + + A class 2 compliant resource MUST meet all class 1 requirements and + support the LOCK method, the DAV:supportedlock property, the DAV: + lockdiscovery property, the Time-Out response header and the Lock- + Token request header. A class 2 compliant resource SHOULD also + support the Timeout request header and the 'owner' XML element. + + Class 2 compliant resources MUST return, at minimum, the values "1" + and "2" in the DAV header on all responses to the OPTIONS method. + +<span class="h3"><h3><a class="selflink" name="section-18.3" href="#section-18.3">18.3</a>. Class 3</h3></span> + + A resource can explicitly advertise its support for the revisions to + [<a href="http://tools.ietf.org/html/rfc2518" title="" http extensions for distributed authoring webdav>RFC2518</a>] made in this document. Class 1 MUST be supported as well. + Class 2 MAY be supported. Advertising class 3 support in addition to + class 1 and 2 means that the server supports all the requirements in + this specification. Advertising class 3 and class 1 support, but not + class 2, means that the server supports all the requirements in this + specification except possibly those that involve locking support. + + + + +<span class="grey">Dusseault Standards Track [Page 103]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-104" id="page-104" href="#page-104" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Example: + + DAV: 1, 3 + +<span class="h2"><h2><a class="selflink" name="section-19" href="#section-19">19</a>. Internationalization Considerations</h2></span> + + In the realm of internationalization, this specification complies + with the IETF Character Set Policy [<a href="http://tools.ietf.org/html/rfc2277" title="" ietf policy on character sets and languages>RFC2277</a>]. In this specification, + human-readable fields can be found either in the value of a property, + or in an error message returned in a response entity body. In both + cases, the human-readable content is encoded using XML, which has + explicit provisions for character set tagging and encoding, and + requires that XML processors read XML elements encoded, at minimum, + using the UTF-8 [<a href="http://tools.ietf.org/html/rfc3629" title="" utf-8 a transformation format of iso>RFC3629</a>] and UTF-16 [<a href="http://tools.ietf.org/html/rfc2781" title="" utf-16 an encoding of iso>RFC2781</a>] encodings of the ISO + 10646 multilingual plane. XML examples in this specification + demonstrate use of the charset parameter of the Content-Type header + (defined in [<a href="http://tools.ietf.org/html/rfc3023" title="" xml media types>RFC3023</a>]), as well as XML charset declarations. + + XML also provides a language tagging capability for specifying the + language of the contents of a particular XML element. The "xml:lang" + attribute appears on an XML element to identify the language of its + content and attributes. See [<a href="#ref-REC-XML" title="" extensible markup language edition>REC-XML</a>] for definitions of values and + scoping. + + WebDAV applications MUST support the character set tagging, character + set encoding, and the language tagging functionality of the XML + specification. Implementors of WebDAV applications are strongly + encouraged to read "XML Media Types" [<a href="http://tools.ietf.org/html/rfc3023" title="" xml media types>RFC3023</a>] for instruction on + which MIME media type to use for XML transport, and on use of the + charset parameter of the Content-Type header. + + Names used within this specification fall into four categories: names + of protocol elements such as methods and headers, names of XML + elements, names of properties, and names of conditions. Naming of + protocol elements follows the precedent of HTTP, using English names + encoded in US-ASCII for methods and headers. Since these protocol + elements are not visible to users, and are simply long token + identifiers, they do not need to support multiple languages. + Similarly, the names of XML elements used in this specification are + not visible to the user and hence do not need to support multiple + languages. + + WebDAV property names are qualified XML names (pairs of XML namespace + name and local name). Although some applications (e.g., a generic + property viewer) will display property names directly to their users, + it is expected that the typical application will use a fixed set of + properties, and will provide a mapping from the property name and + namespace to a human-readable field when displaying the property name + + + +<span class="grey">Dusseault Standards Track [Page 104]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-105" id="page-105" href="#page-105" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + to a user. It is only in the case where the set of properties is not + known ahead of time that an application need display a property name + to a user. We recommend that applications provide human-readable + property names wherever feasible. + + For error reporting, we follow the convention of HTTP/1.1 status + codes, including with each status code a short, English description + of the code (e.g., 423 (Locked)). While the possibility exists that + a poorly crafted user agent would display this message to a user, + internationalized applications will ignore this message, and display + an appropriate message in the user's language and character set. + + Since interoperation of clients and servers does not require locale + information, this specification does not specify any mechanism for + transmission of this information. + +<span class="h2"><h2><a class="selflink" name="section-20" href="#section-20">20</a>. Security Considerations</h2></span> + + This section is provided to detail issues concerning security + implications of which WebDAV applications need to be aware. + + All of the security considerations of HTTP/1.1 (discussed in + [<a href="http://tools.ietf.org/html/rfc2616" title="" hypertext transfer protocol http>RFC2616</a>]) and XML (discussed in [<a href="http://tools.ietf.org/html/rfc3023" title="" xml media types>RFC3023</a>]) also apply to WebDAV. In + addition, the security risks inherent in remote authoring require + stronger authentication technology, introduce several new privacy + concerns, and may increase the hazards from poor server design. + These issues are detailed below. + +<span class="h3"><h3><a class="selflink" name="section-20.1" href="#section-20.1">20.1</a>. Authentication of Clients</h3></span> + + Due to their emphasis on authoring, WebDAV servers need to use + authentication technology to protect not just access to a network + resource, but the integrity of the resource as well. Furthermore, + the introduction of locking functionality requires support for + authentication. + + A password sent in the clear over an insecure channel is an + inadequate means for protecting the accessibility and integrity of a + resource as the password may be intercepted. Since Basic + authentication for HTTP/1.1 performs essentially clear text + transmission of a password, Basic authentication MUST NOT be used to + authenticate a WebDAV client to a server unless the connection is + secure. Furthermore, a WebDAV server MUST NOT send a Basic + authentication challenge in a WWW-Authenticate header unless the + connection is secure. An example of a secure connection would be a + Transport Layer Security (TLS) connection employing a strong cipher + suite and server authentication. + + + + +<span class="grey">Dusseault Standards Track [Page 105]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-106" id="page-106" href="#page-106" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + WebDAV applications MUST support the Digest authentication scheme + [<a href="http://tools.ietf.org/html/rfc2617" title="" http authentication: basic and digest access authentication>RFC2617</a>]. Since Digest authentication verifies that both parties to + a communication know a shared secret, a password, without having to + send that secret in the clear, Digest authentication avoids the + security problems inherent in Basic authentication while providing a + level of authentication that is useful in a wide range of scenarios. + +<span class="h3"><h3><a class="selflink" name="section-20.2" href="#section-20.2">20.2</a>. Denial of Service</h3></span> + + Denial-of-service attacks are of special concern to WebDAV servers. + WebDAV plus HTTP enables denial-of-service attacks on every part of a + system's resources. + + o The underlying storage can be attacked by PUTting extremely large + files. + + o Asking for recursive operations on large collections can attack + processing time. + + o Making multiple pipelined requests on multiple connections can + attack network connections. + + WebDAV servers need to be aware of the possibility of a denial-of- + service attack at all levels. The proper response to such an attack + MAY be to simply drop the connection. Or, if the server is able to + make a response, the server MAY use a 400-level status request such + as 400 (Bad Request) and indicate why the request was refused (a 500- + level status response would indicate that the problem is with the + server, whereas unintentional DoS attacks are something the client is + capable of remedying). + +<span class="h3"><h3><a class="selflink" name="section-20.3" href="#section-20.3">20.3</a>. Security through Obscurity</h3></span> + + WebDAV provides, through the PROPFIND method, a mechanism for listing + the member resources of a collection. This greatly diminishes the + effectiveness of security or privacy techniques that rely only on the + difficulty of discovering the names of network resources. Users of + WebDAV servers are encouraged to use access control techniques to + prevent unwanted access to resources, rather than depending on the + relative obscurity of their resource names. + +<span class="h3"><h3><a class="selflink" name="section-20.4" href="#section-20.4">20.4</a>. Privacy Issues Connected to Locks</h3></span> + + When submitting a lock request, a user agent may also submit an + 'owner' XML field giving contact information for the person taking + out the lock (for those cases where a person, rather than a robot, is + taking out the lock). This contact information is stored in a DAV: + lockdiscovery property on the resource, and can be used by other + + + +<span class="grey">Dusseault Standards Track [Page 106]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-107" id="page-107" href="#page-107" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + collaborators to begin negotiation over access to the resource. + However, in many cases, this contact information can be very private, + and should not be widely disseminated. Servers SHOULD limit read + access to the DAV:lockdiscovery property as appropriate. + Furthermore, user agents SHOULD provide control over whether contact + information is sent at all, and if contact information is sent, + control over exactly what information is sent. + +<span class="h3"><h3><a class="selflink" name="section-20.5" href="#section-20.5">20.5</a>. Privacy Issues Connected to Properties</h3></span> + + Since property values are typically used to hold information such as + the author of a document, there is the possibility that privacy + concerns could arise stemming from widespread access to a resource's + property data. To reduce the risk of inadvertent release of private + information via properties, servers are encouraged to develop access + control mechanisms that separate read access to the resource body and + read access to the resource's properties. This allows a user to + control the dissemination of their property data without overly + restricting access to the resource's contents. + +<span class="h3"><h3><a class="selflink" name="section-20.6" href="#section-20.6">20.6</a>. Implications of XML Entities</h3></span> + + XML supports a facility known as "external entities", defined in + Section 4.2.2 of [<a href="#ref-REC-XML" title="" extensible markup language edition>REC-XML</a>], which instructs an XML processor to + retrieve and include additional XML. An external XML entity can be + used to append or modify the document type declaration (DTD) + associated with an XML document. An external XML entity can also be + used to include XML within the content of an XML document. For non- + validating XML, such as the XML used in this specification, including + an external XML entity is not required by XML. However, XML does + state that an XML processor may, at its discretion, include the + external XML entity. + + External XML entities have no inherent trustworthiness and are + subject to all the attacks that are endemic to any HTTP GET request. + Furthermore, it is possible for an external XML entity to modify the + DTD, and hence affect the final form of an XML document, in the worst + case, significantly modifying its semantics or exposing the XML + processor to the security risks discussed in [<a href="http://tools.ietf.org/html/rfc3023" title="" xml media types>RFC3023</a>]. Therefore, + implementers must be aware that external XML entities should be + treated as untrustworthy. If a server chooses not to handle external + XML entities, it SHOULD respond to requests containing external + entities with the 'no-external-entities' condition code. + + There is also the scalability risk that would accompany a widely + deployed application that made use of external XML entities. In this + situation, it is possible that there would be significant numbers of + requests for one external XML entity, potentially overloading any + + + +<span class="grey">Dusseault Standards Track [Page 107]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-108" id="page-108" href="#page-108" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + server that fields requests for the resource containing the external + XML entity. + + Furthermore, there's also a risk based on the evaluation of "internal + entities" as defined in Section 4.2.2 of [<a href="#ref-REC-XML" title="" extensible markup language edition>REC-XML</a>]. A small, + carefully crafted request using nested internal entities may require + enormous amounts of memory and/or processing time to process. Server + implementers should be aware of this risk and configure their XML + parsers so that requests like these can be detected and rejected as + early as possible. + +<span class="h3"><h3><a class="selflink" name="section-20.7" href="#section-20.7">20.7</a>. Risks Connected with Lock Tokens</h3></span> + + This specification encourages the use of "A Universally Unique + Identifier (UUID) URN Namespace" ([<a href="http://tools.ietf.org/html/rfc4122" title="" a universally unique identifier urn namespace>RFC4122</a>]) for lock tokens + (<a href="#section-6.5">Section 6.5</a>), in order to guarantee their uniqueness across space + and time. Version 1 UUIDs (defined in <a href="#section-4">Section 4</a>) MAY contain a + "node" field that "consists of an IEEE 802 MAC address, usually the + host address. For systems with multiple IEEE addresses, any + available one can be used". Since a WebDAV server will issue many + locks over its lifetime, the implication is that it may also be + publicly exposing its IEEE 802 address. + + There are several risks associated with exposure of IEEE 802 + addresses. Using the IEEE 802 address: + + o It is possible to track the movement of hardware from subnet to + subnet. + + o It may be possible to identify the manufacturer of the hardware + running a WebDAV server. + + o It may be possible to determine the number of each type of + computer running WebDAV. + + This risk only applies to host-address-based UUID versions. <a href="#section-4">Section</a> + <a href="#section-4">4</a> of [<a href="http://tools.ietf.org/html/rfc4122" title="" a universally unique identifier urn namespace>RFC4122</a>] describes several other mechanisms for generating + UUIDs that do not involve the host address and therefore do not + suffer from this risk. + +<span class="h3"><h3><a class="selflink" name="section-20.8" href="#section-20.8">20.8</a>. Hosting Malicious Content</h3></span> + + HTTP has the ability to host programs that are executed on client + machines. These programs can take many forms including Web scripts, + executables, plug-in modules, and macros in documents. WebDAV does + not change any of the security concerns around these programs, yet + often WebDAV is used in contexts where a wide range of users can + publish documents on a server. The server might not have a close + + + +<span class="grey">Dusseault Standards Track [Page 108]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-109" id="page-109" href="#page-109" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + trust relationship with the author that is publishing the document. + Servers that allow clients to publish arbitrary content can usefully + implement precautions to check that content published to the server + is not harmful to other clients. Servers could do this by techniques + such as restricting the types of content that is allowed to be + published and running virus and malware detection software on + published content. Servers can also mitigate the risk by having + appropriate access restriction and authentication of users that are + allowed to publish content to the server. + +<span class="h2"><h2><a class="selflink" name="section-21" href="#section-21">21</a>. IANA Considerations</h2></span> + +<span class="h3"><h3><a class="selflink" name="section-21.1" href="#section-21.1">21.1</a>. New URI Schemes</h3></span> + + This specification defines two URI schemes: + + 1. the "opaquelocktoken" scheme defined in <a href="#appendix-C">Appendix C</a>, and + + 2. the "DAV" URI scheme, which historically was used in [<a href="http://tools.ietf.org/html/rfc2518" title="" http extensions for distributed authoring webdav>RFC2518</a>] to + disambiguate WebDAV property and XML element names and which + continues to be used for that purpose in this specification and + others extending WebDAV. Creation of identifiers in the "DAV:" + namespace is controlled by the IETF. + + Note that defining new URI schemes for XML namespaces is now + discouraged. "DAV:" was defined before standard best practices + emerged. + +<span class="h3"><h3><a class="selflink" name="section-21.2" href="#section-21.2">21.2</a>. XML Namespaces</h3></span> + + XML namespaces disambiguate WebDAV property names and XML elements. + Any WebDAV user or application can define a new namespace in order to + create custom properties or extend WebDAV XML syntax. IANA does not + need to manage such namespaces, property names, or element names. + +<span class="h3"><h3><a class="selflink" name="section-21.3" href="#section-21.3">21.3</a>. Message Header Fields</h3></span> + + The message header fields below should be added to the permanent + registry (see [<a href="http://tools.ietf.org/html/rfc3864" title="" registration procedures for message header fields>RFC3864</a>]). + +<span class="h4"><h4><a class="selflink" name="section-21.3.1" href="#section-21.3.1">21.3.1</a>. DAV</h4></span> + + Header field name: DAV + + Applicable protocol: http + + Status: standard + + + + +<span class="grey">Dusseault Standards Track [Page 109]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-110" id="page-110" href="#page-110" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Author/Change controller: IETF + + Specification document: this specification (<a href="#section-10.1">Section 10.1</a>) + +<span class="h4"><h4><a class="selflink" name="section-21.3.2" href="#section-21.3.2">21.3.2</a>. Depth</h4></span> + + Header field name: Depth + + Applicable protocol: http + + Status: standard + + Author/Change controller: IETF + + Specification document: this specification (<a href="#section-10.2">Section 10.2</a>) + +<span class="h4"><h4><a class="selflink" name="section-21.3.3" href="#section-21.3.3">21.3.3</a>. Destination</h4></span> + + Header field name: Destination + + Applicable protocol: http + + Status: standard + + Author/Change controller: IETF + + Specification document: this specification (<a href="#section-10.3">Section 10.3</a>) + +<span class="h4"><h4><a class="selflink" name="section-21.3.4" href="#section-21.3.4">21.3.4</a>. If</h4></span> + + Header field name: If + + Applicable protocol: http + + Status: standard + + Author/Change controller: IETF + + Specification document: this specification (<a href="#section-10.4">Section 10.4</a>) + +<span class="h4"><h4><a class="selflink" name="section-21.3.5" href="#section-21.3.5">21.3.5</a>. Lock-Token</h4></span> + + Header field name: Lock-Token + + Applicable protocol: http + + Status: standard + + + + +<span class="grey">Dusseault Standards Track [Page 110]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-111" id="page-111" href="#page-111" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + Author/Change controller: IETF + + Specification document: this specification (<a href="#section-10.5">Section 10.5</a>) + +<span class="h4"><h4><a class="selflink" name="section-21.3.6" href="#section-21.3.6">21.3.6</a>. Overwrite</h4></span> + + Header field name: Overwrite + + Applicable protocol: http + + Status: standard + + Author/Change controller: IETF + + Specification document: this specification (<a href="#section-10.6">Section 10.6</a>) + +<span class="h4"><h4><a class="selflink" name="section-21.3.7" href="#section-21.3.7">21.3.7</a>. Timeout</h4></span> + + Header field name: Timeout + + Applicable protocol: http + + Status: standard + + Author/Change controller: IETF + + Specification document: this specification (<a href="#section-10.7">Section 10.7</a>) + +<span class="h3"><h3><a class="selflink" name="section-21.4" href="#section-21.4">21.4</a>. HTTP Status Codes</h3></span> + + This specification defines the HTTP status codes + + o 207 Multi-Status (<a href="#section-11.1">Section 11.1</a>) + + o 422 Unprocessable Entity (<a href="#section-11.2">Section 11.2</a>), + + o 423 Locked (<a href="#section-11.3">Section 11.3</a>), + + o 424 Failed Dependency (<a href="#section-11.4">Section 11.4</a>) and + + o 507 Insufficient Storage (<a href="#section-11.5">Section 11.5</a>), + + to be updated in the registry at + <<a href="http://www.iana.org/assignments/http-status-codes">http://www.iana.org/assignments/http-status-codes</a>>. + + Note: the HTTP status code 102 (Processing) has been removed in this + specification; its IANA registration should continue to reference <a href="http://tools.ietf.org/html/rfc2518">RFC</a> + <a href="http://tools.ietf.org/html/rfc2518">2518</a>. + + + +<span class="grey">Dusseault Standards Track [Page 111]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-112" id="page-112" href="#page-112" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="section-22" href="#section-22">22</a>. Acknowledgements</h2></span> + + A specification such as this thrives on piercing critical review and + withers from apathetic neglect. The authors gratefully acknowledge + the contributions of the following people, whose insights were so + valuable at every stage of our work. + + Contributors to <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a> + + Terry Allen, Harald Alvestrand, Jim Amsden, Becky Anderson, Alan + Babich, Sanford Barr, Dylan Barrell, Bernard Chester, Tim Berners- + Lee, Dan Connolly, Jim Cunningham, Ron Daniel, Jr., Jim Davis, Keith + Dawson, Mark Day, Brian Deen, Martin Duerst, David Durand, Lee + Farrell, Chuck Fay, Wesley Felter, Roy Fielding, Mark Fisher, Alan + Freier, George Florentine, Jim Gettys, Phill Hallam-Baker, Dennis + Hamilton, Steve Henning, Mead Himelstein, Alex Hopmann, Andre van der + Hoek, Ben Laurie, Paul Leach, Ora Lassila, Karen MacArthur, Steven + Martin, Larry Masinter, Michael Mealling, Keith Moore, Thomas Narten, + Henrik Nielsen, Kenji Ota, Bob Parker, Glenn Peterson, Jon Radoff, + Saveen Reddy, Henry Sanders, Christopher Seiwald, Judith Slein, Mike + Spreitzer, Einar Stefferud, Greg Stein, Ralph Swick, Kenji Takahashi, + Richard N. Taylor, Robert Thau, John Turner, Sankar Virdhagriswaran, + Fabio Vitali, Gregory Woodhouse, and Lauren Wood. + + Two from this list deserve special mention. The contributions by + Larry Masinter have been invaluable; he both helped the formation of + the working group and patiently coached the authors along the way. + In so many ways he has set high standards that we have toiled to + meet. The contributions of Judith Slein were also invaluable; by + clarifying the requirements and in patiently reviewing version after + version, she both improved this specification and expanded our minds + on document management. + + We would also like to thank John Turner for developing the XML DTD. + + The authors of <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a> were Yaron Goland, Jim Whitehead, A. Faizi, + Steve Carter, and D. Jensen. Although their names had to be removed + due to IETF author count restrictions, they can take credit for the + majority of the design of WebDAV. + + Additional Acknowledgements for This Specification + + Significant contributors of text for this specification are listed as + contributors in the section below. We must also gratefully + acknowledge Geoff Clemm, Joel Soderberg, and Dan Brotsky for hashing + out specific text on the list or in meetings. Joe Hildebrand and + Cullen Jennings helped close many issues. Barry Lind described an + additional security consideration and Cullen Jennings provided text + + + +<span class="grey">Dusseault Standards Track [Page 112]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-113" id="page-113" href="#page-113" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + for that consideration. Jason Crawford tracked issue status for this + document for a period of years, followed by Elias Sinderson. + +<span class="h2"><h2><a class="selflink" name="section-23" href="#section-23">23</a>. Contributors to This Specification</h2></span> + + Julian Reschke + <green/>bytes GmbH + Hafenweg 16, 48155 Muenster, Germany + EMail: julian.reschke@greenbytes.de + + + Elias Sinderson + University of California, Santa Cruz + 1156 High Street, Santa Cruz, CA 95064 + EMail: elias@cse.ucsc.edu + + + Jim Whitehead + University of California, Santa Cruz + 1156 High Street, Santa Cruz, CA 95064 + EMail: ejw@soe.ucsc.edu + +<span class="h2"><h2><a class="selflink" name="section-24" href="#section-24">24</a>. Authors of <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a></h2></span> + + Y. Y. Goland + Microsoft Corporation + One Microsoft Way + Redmond, WA 98052-6399 + EMail: yarong@microsoft.com + + + E. J. Whitehead, Jr. + Dept. Of Information and Computer Science + University of California, Irvine + Irvine, CA 92697-3425 + EMail: ejw@ics.uci.edu + + + A. Faizi + Netscape + 685 East Middlefield Road + Mountain View, CA 94043 + EMail: asad@netscape.com + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 113]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-114" id="page-114" href="#page-114" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + S. R. Carter + Novell + 1555 N. Technology Way + M/S ORM F111 + Orem, UT 84097-2399 + EMail: srcarter@novell.com + + + D. Jensen + Novell + 1555 N. Technology Way + M/S ORM F111 + Orem, UT 84097-2399 + EMail: dcjensen@novell.com + +<span class="h2"><h2><a class="selflink" name="section-25" href="#section-25">25</a>. References</h2></span> + +<span class="h3"><h3><a class="selflink" name="section-25.1" href="#section-25.1">25.1</a>. Normative References</h3></span> + + [<a name="ref-REC-XML" id="ref-REC-XML">REC-XML</a>] Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, + E., and F. Yergeau, "Extensible Markup Language + (XML) 1.0 (Fourth Edition)", W3C REC-xml-20060816, + August 2006, + <<a href="http://www.w3.org/TR/2006/REC-xml-20060816/">http://www.w3.org/TR/2006/REC-xml-20060816/</a>>. + + [<a name="ref-REC-XML-INFOSET" id="ref-REC-XML-INFOSET">REC-XML-INFOSET</a>] Cowan, J. and R. Tobin, "XML Information Set + (Second Edition)", W3C REC-xml-infoset-20040204, + February 2004, <<a href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/">http://www.w3.org/TR/2004/</a> + <a href="http://www.w3.org/TR/2004/REC-xml-infoset-20040204/">REC-xml-infoset-20040204/</a>>. + + [<a name="ref-REC-XML-NAMES" id="ref-REC-XML-NAMES">REC-XML-NAMES</a>] Bray, T., Hollander, D., Layman, A., and R. Tobin, + "Namespaces in XML 1.0 (Second Edition)", W3C REC- + xml-names-20060816, August 2006, <<a href="http://www.w3.org/TR/2006/REC-xml-names-20060816/">http://</a> + <a href="http://www.w3.org/TR/2006/REC-xml-names-20060816/">www.w3.org/TR/2006/REC-xml-names-20060816/</a>>. + + [<a name="ref-RFC2119" id="ref-RFC2119">RFC2119</a>] Bradner, S., "Key words for use in RFCs to + Indicate Requirement Levels", <a href="http://tools.ietf.org/html/bcp14">BCP 14</a>, <a href="http://tools.ietf.org/html/rfc2119">RFC 2119</a>, + March 1997. + + [<a name="ref-RFC2277" id="ref-RFC2277">RFC2277</a>] Alvestrand, H., "IETF Policy on Character Sets and + Languages", <a href="http://tools.ietf.org/html/bcp18">BCP 18</a>, <a href="http://tools.ietf.org/html/rfc2277">RFC 2277</a>, January 1998. + + [<a name="ref-RFC2616" id="ref-RFC2616">RFC2616</a>] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., + Masinter, L., Leach, P., and T. Berners-Lee, + "Hypertext Transfer Protocol -- HTTP/1.1", + <a href="http://tools.ietf.org/html/rfc2616">RFC 2616</a>, June 1999. + + + + + +<span class="grey">Dusseault Standards Track [Page 114]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-115" id="page-115" href="#page-115" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + [<a name="ref-RFC2617" id="ref-RFC2617">RFC2617</a>] Franks, J., Hallam-Baker, P., Hostetler, J., + Lawrence, S., Leach, P., Luotonen, A., and L. + Stewart, "HTTP Authentication: Basic and Digest + Access Authentication", <a href="http://tools.ietf.org/html/rfc2617">RFC 2617</a>, June 1999. + + [<a name="ref-RFC3339" id="ref-RFC3339">RFC3339</a>] Klyne, G., Ed. and C. Newman, "Date and Time on + the Internet: Timestamps", <a href="http://tools.ietf.org/html/rfc3339">RFC 3339</a>, July 2002. + + [<a name="ref-RFC3629" id="ref-RFC3629">RFC3629</a>] Yergeau, F., "UTF-8, a transformation format of + ISO 10646", STD 63, <a href="http://tools.ietf.org/html/rfc3629">RFC 3629</a>, November 2003. + + [<a name="ref-RFC3986" id="ref-RFC3986">RFC3986</a>] Berners-Lee, T., Fielding, R., and L. Masinter, + "Uniform Resource Identifier (URI): Generic + Syntax", STD 66, <a href="http://tools.ietf.org/html/rfc3986">RFC 3986</a>, January 2005. + + [<a name="ref-RFC4122" id="ref-RFC4122">RFC4122</a>] Leach, P., Mealling, M., and R. Salz, "A + Universally Unique IDentifier (UUID) URN + Namespace", <a href="http://tools.ietf.org/html/rfc4122">RFC 4122</a>, July 2005. + +<span class="h3"><h3><a class="selflink" name="section-25.2" href="#section-25.2">25.2</a>. Informative References</h3></span> + + [<a name="ref-RFC2291" id="ref-RFC2291">RFC2291</a>] Slein, J., Vitali, F., Whitehead, E., and D. + Durand, "Requirements for a Distributed Authoring + and Versioning Protocol for the World Wide Web", + <a href="http://tools.ietf.org/html/rfc2291">RFC 2291</a>, February 1998. + + [<a name="ref-RFC2518" id="ref-RFC2518">RFC2518</a>] Goland, Y., Whitehead, E., Faizi, A., Carter, S., + and D. Jensen, "HTTP Extensions for Distributed + Authoring -- WEBDAV", <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a>, February 1999. + + [<a name="ref-RFC2781" id="ref-RFC2781">RFC2781</a>] Hoffman, P. and F. Yergeau, "UTF-16, an encoding + of ISO 10646", <a href="http://tools.ietf.org/html/rfc2781">RFC 2781</a>, February 2000. + + [<a name="ref-RFC3023" id="ref-RFC3023">RFC3023</a>] Murata, M., St. Laurent, S., and D. Kohn, "XML + Media Types", <a href="http://tools.ietf.org/html/rfc3023">RFC 3023</a>, January 2001. + + [<a name="ref-RFC3253" id="ref-RFC3253">RFC3253</a>] Clemm, G., Amsden, J., Ellison, T., Kaler, C., and + J. Whitehead, "Versioning Extensions to WebDAV + (Web Distributed Authoring and Versioning)", + <a href="http://tools.ietf.org/html/rfc3253">RFC 3253</a>, March 2002. + + [<a name="ref-RFC3648" id="ref-RFC3648">RFC3648</a>] Whitehead, J. and J. Reschke, Ed., "Web + Distributed Authoring and Versioning (WebDAV) + Ordered Collections Protocol", <a href="http://tools.ietf.org/html/rfc3648">RFC 3648</a>, + December 2003. + + + + + + +<span class="grey">Dusseault Standards Track [Page 115]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-116" id="page-116" href="#page-116" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + [<a name="ref-RFC3744" id="ref-RFC3744">RFC3744</a>] Clemm, G., Reschke, J., Sedlar, E., and J. + Whitehead, "Web Distributed Authoring and + Versioning (WebDAV) Access Control Protocol", + <a href="http://tools.ietf.org/html/rfc3744">RFC 3744</a>, May 2004. + + [<a name="ref-RFC3864" id="ref-RFC3864">RFC3864</a>] Klyne, G., Nottingham, M., and J. Mogul, + "Registration Procedures for Message Header + Fields", <a href="http://tools.ietf.org/html/bcp90">BCP 90</a>, <a href="http://tools.ietf.org/html/rfc3864">RFC 3864</a>, September 2004. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 116]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-117" id="page-117" href="#page-117" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="appendix-A" href="#appendix-A">Appendix A</a>. Notes on Processing XML Elements</h2></span> + +<span class="h1"><h1><a class="selflink" name="appendix-A.1" href="#appendix-A.1">A.1</a>. Notes on Empty XML Elements</h1></span> + + XML supports two mechanisms for indicating that an XML element does + not have any content. The first is to declare an XML element of the + form <A></A>. The second is to declare an XML element of the form + <A/>. The two XML elements are semantically identical. + +<span class="h1"><h1><a class="selflink" name="appendix-A.2" href="#appendix-A.2">A.2</a>. Notes on Illegal XML Processing</h1></span> + + XML is a flexible data format that makes it easy to submit data that + appears legal but in fact is not. The philosophy of "Be flexible in + what you accept and strict in what you send" still applies, but it + must not be applied inappropriately. XML is extremely flexible in + dealing with issues of whitespace, element ordering, inserting new + elements, etc. This flexibility does not require extension, + especially not in the area of the meaning of elements. + + There is no kindness in accepting illegal combinations of XML + elements. At best, it will cause an unwanted result and at worst it + can cause real damage. + +<span class="h1"><h1><a class="selflink" name="appendix-A.3" href="#appendix-A.3">A.3</a>. Example - XML Syntax Error</h1></span> + + The following request body for a PROPFIND method is illegal. + + <?xml version="1.0" encoding="utf-8" ?> + <D:propfind xmlns:D="DAV:"> + <D:allprop/> + <D:propname/> + </D:propfind> + + The definition of the propfind element only allows for the allprop or + the propname element, not both. Thus, the above is an error and must + be responded to with a 400 (Bad Request). + + Imagine, however, that a server wanted to be "kind" and decided to + pick the allprop element as the true element and respond to it. A + client running over a bandwidth limited line who intended to execute + a propname would be in for a big surprise if the server treated the + command as an allprop. + + Additionally, if a server were lenient and decided to reply to this + request, the results would vary randomly from server to server, with + some servers executing the allprop directive, and others executing + the propname directive. This reduces interoperability rather than + increasing it. + + + +<span class="grey">Dusseault Standards Track [Page 117]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-118" id="page-118" href="#page-118" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h1"><h1><a class="selflink" name="appendix-A.4" href="#appendix-A.4">A.4</a>. Example - Unexpected XML Element</h1></span> + + The previous example was illegal because it contained two elements + that were explicitly banned from appearing together in the propfind + element. However, XML is an extensible language, so one can imagine + new elements being defined for use with propfind. Below is the + request body of a PROPFIND and, like the previous example, must be + rejected with a 400 (Bad Request) by a server that does not + understand the expired-props element. + + <?xml version="1.0" encoding="utf-8" ?> + <D:propfind xmlns:D="DAV:" + xmlns:E="http://www.example.com/standards/props/"> + <E:expired-props/> + </D:propfind> + + To understand why a 400 (Bad Request) is returned, let us look at the + request body as the server unfamiliar with expired-props sees it. + + <?xml version="1.0" encoding="utf-8" ?> + <D:propfind xmlns:D="DAV:" + xmlns:E="http://www.example.com/standards/props/"> + </D:propfind> + + As the server does not understand the 'expired-props' element, + according to the WebDAV-specific XML processing rules specified in + <a href="#section-17">Section 17</a>, it must process the request as if the element were not + there. Thus, the server sees an empty propfind, which by the + definition of the propfind element is illegal. + + Please note that had the extension been additive, it would not + necessarily have resulted in a 400 (Bad Request). For example, + imagine the following request body for a PROPFIND: + + + <?xml version="1.0" encoding="utf-8" ?> + <D:propfind xmlns:D="DAV:" + xmlns:E="http://www.example.com/standards/props/"> + <D:propname/> + <E:leave-out>*boss*</E:leave-out> + </D:propfind> + + The previous example contains the fictitious element leave-out. Its + purpose is to prevent the return of any property whose name matches + the submitted pattern. If the previous example were submitted to a + server unfamiliar with 'leave-out', the only result would be that the + 'leave-out' element would be ignored and a propname would be + executed. + + + +<span class="grey">Dusseault Standards Track [Page 118]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-119" id="page-119" href="#page-119" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="appendix-B" href="#appendix-B">Appendix B</a>. Notes on HTTP Client Compatibility</h2></span> + + WebDAV was designed to be, and has been found to be, backward- + compatible with HTTP 1.1. The PUT and DELETE methods are defined in + HTTP and thus may be used by HTTP clients as well as WebDAV-aware + clients, but the responses to PUT and DELETE have been extended in + this specification in ways that only a WebDAV client would be + entirely prepared for. Some theoretical concerns were raised about + whether those responses would cause interoperability problems with + HTTP-only clients, and this section addresses those concerns. + + Since any HTTP client ought to handle unrecognized 400-level and 500- + level status codes as errors, the following new status codes should + not present any issues: 422, 423, and 507 (424 is also a new status + code but it appears only in the body of a Multistatus response.) So, + for example, if an HTTP client attempted to PUT or DELETE a locked + resource, the 423 Locked response ought to result in a generic error + presented to the user. + + The 207 Multistatus response is interesting because an HTTP client + issuing a DELETE request to a collection might interpret a 207 + response as a success, even though it does not realize the resource + is a collection and cannot understand that the DELETE operation might + have been a complete or partial failure. That interpretation isn't + entirely justified, because a 200-level response indicates that the + server "received, understood, and accepted" the request, not that the + request resulted in complete success. + + One option is that a server could treat a DELETE of a collection as + an atomic operation, and use either 204 No Content in case of + success, or some appropriate error response (400 or 500 level) for an + error. This approach would indeed maximize backward compatibility. + However, since interoperability tests and working group discussions + have not turned up any instances of HTTP clients issuing a DELETE + request against a WebDAV collection, this concern is more theoretical + than practical. Thus, servers are likely to be completely successful + at interoperating with HTTP clients even if they treat any collection + DELETE request as a WebDAV request and send a 207 Multi-Status + response. + + In general, server implementations are encouraged to use the detailed + responses and other mechanisms defined in this document rather than + make changes for theoretical interoperability concerns. + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 119]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-120" id="page-120" href="#page-120" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +<span class="h2"><h2><a class="selflink" name="appendix-C" href="#appendix-C">Appendix C</a>. The 'opaquelocktoken' Scheme and URIs</h2></span> + + The 'opaquelocktoken' URI scheme was defined in [<a href="http://tools.ietf.org/html/rfc2518" title="" http extensions for distributed authoring webdav>RFC2518</a>] (and + registered by IANA) in order to create syntactically correct and + easy-to-generate URIs out of UUIDs, intended to be used as lock + tokens and to be unique across all resources for all time. + + An opaquelocktoken URI is constructed by concatenating the + 'opaquelocktoken' scheme with a UUID, along with an optional + extension. Servers can create new UUIDs for each new lock token. If + a server wishes to reuse UUIDs, the server MUST add an extension, and + the algorithm generating the extension MUST guarantee that the same + extension will never be used twice with the associated UUID. + + OpaqueLockToken-URI = "opaquelocktoken:" UUID [Extension] + ; UUID is defined in <a href="http://tools.ietf.org/html/rfc4122#section-3">Section 3 of [RFC4122]</a>. Note that LWS + ; is not allowed between elements of + ; this production. + + Extension = path + ; path is defined in <a href="http://tools.ietf.org/html/rfc3986#section-3.3">Section 3.3 of [RFC3986]</a> + + +<span class="h2"><h2><a class="selflink" name="appendix-D" href="#appendix-D">Appendix D</a>. Lock-null Resources</h2></span> + + The original WebDAV model for locking unmapped URLs created "lock- + null resources". This model was over-complicated and some + interoperability and implementation problems were discovered. The + new WebDAV model for locking unmapped URLs (see <a href="#section-7.3">Section 7.3</a>) creates + "locked empty resources". Lock-null resources are deprecated. This + section discusses the original model briefly because clients MUST be + able to handle either model. + + In the original "lock-null resource" model, which is no longer + recommended for implementation: + + o A lock-null resource sometimes appeared as "Not Found". The + server responds with a 404 or 405 to any method except for PUT, + MKCOL, OPTIONS, PROPFIND, LOCK, UNLOCK. + + o A lock-null resource does however show up as a member of its + parent collection. + + o The server removes the lock-null resource entirely (its URI + becomes unmapped) if its lock goes away before it is converted to + a regular resource. Recall that locks go away not only when they + expire or are unlocked, but are also removed if a resource is + renamed or moved, or if any parent collection is renamed or moved. + + + +<span class="grey">Dusseault Standards Track [Page 120]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-121" id="page-121" href="#page-121" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + o The server converts the lock-null resource into a regular resource + if a PUT request to the URL is successful. + + o The server converts the lock-null resource into a collection if a + MKCOL request to the URL is successful (though interoperability + experience showed that not all servers followed this requirement). + + o Property values were defined for DAV:lockdiscovery and DAV: + supportedlock properties but not necessarily for other properties + like DAV:getcontenttype. + + Clients can easily interoperate both with servers that support the + old model "lock-null resources" and the recommended model of "locked + empty resources" by only attempting PUT after a LOCK to an unmapped + URL, not MKCOL or GET. + +<span class="h1"><h1><a class="selflink" name="appendix-D.1" href="#appendix-D.1">D.1</a>. Guidance for Clients Using LOCK to Create Resources</h1></span> + + A WebDAV client implemented to this specification might find servers + that create lock-null resources (implemented before this + specification using [<a href="http://tools.ietf.org/html/rfc2518" title="" http extensions for distributed authoring webdav>RFC2518</a>]) as well as servers that create locked + empty resources. The response to the LOCK request will not indicate + what kind of resource was created. There are a few techniques that + help the client deal with either type. + + If the client wishes to avoid accidentally creating either lock- + null or empty locked resources, an "If-Match: *" header can be + included with LOCK requests to prevent the server from creating a + new resource. + + If a LOCK request creates a resource and the client subsequently + wants to overwrite that resource using a COPY or MOVE request, the + client should include an "Overwrite: T" header. + + If a LOCK request creates a resource and the client then decides + to get rid of that resource, a DELETE request is supposed to fail + on a lock-null resource and UNLOCK should be used instead. But + with a locked empty resource, UNLOCK doesn't make the resource + disappear. Therefore, the client might have to try both requests + and ignore an error in one of the two requests. + +<span class="h2"><h2><a class="selflink" name="appendix-E" href="#appendix-E">Appendix E</a>. Guidance for Clients Desiring to Authenticate</h2></span> + + Many WebDAV clients that have already been implemented have account + settings (similar to the way email clients store IMAP account + settings). Thus, the WebDAV client would be able to authenticate + with its first couple requests to the server, provided it had a way + to get the authentication challenge from the server with realm name, + + + +<span class="grey">Dusseault Standards Track [Page 121]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-122" id="page-122" href="#page-122" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + nonce, and other challenge information. Note that the results of + some requests might vary according to whether or not the client is + authenticated -- a PROPFIND might return more visible resources if + the client is authenticated, yet not fail if the client is anonymous. + + There are a number of ways the client might be able to trigger the + server to provide an authentication challenge. This appendix + describes a couple approaches that seem particularly likely to work. + + The first approach is to perform a request that ought to require + authentication. However, it's possible that a server might handle + any request even without authentication, so to be entirely safe, the + client could add a conditional header to ensure that even if the + request passes permissions checks, it's not actually handled by the + server. An example of following this approach would be to use a PUT + request with an "If-Match" header with a made-up ETag value. This + approach might fail to result in an authentication challenge if the + server does not test authorization before testing conditionals as is + required (see <a href="#section-8.5">Section 8.5</a>), or if the server does not need to test + authorization. + + Example - forcing auth challenge with write request + + >>Request + + PUT /forceauth.txt HTTP/1.1 + Host: www.example.com + If-Match: "xxx" + Content-Type: text/plain + Content-Length: 0 + + + The second approach is to use an Authorization header (defined in + [<a href="http://tools.ietf.org/html/rfc2617" title="" http authentication: basic and digest access authentication>RFC2617</a>]), which is likely to be rejected by the server but which + will then prompt a proper authentication challenge. For example, the + client could start with a PROPFIND request containing an + Authorization header containing a made-up Basic userid:password + string or with actual plausible credentials. This approach relies on + the server responding with a "401 Unauthorized" along with a + challenge if it receives an Authorization header with an unrecognized + username, invalid password, or if it doesn't even handle Basic + authentication. This seems likely to work because of the + requirements of <a href="http://tools.ietf.org/html/rfc2617">RFC 2617</a>: + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 122]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-123" id="page-123" href="#page-123" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + "If the origin server does not wish to accept the credentials sent + with a request, it SHOULD return a 401 (Unauthorized) response. The + response MUST include a WWW-Authenticate header field containing at + least one (possibly new) challenge applicable to the requested + resource." + + There's a slight problem with implementing that recommendation in + some cases, because some servers do not even have challenge + information for certain resources. Thus, when there's no way to + authenticate to a resource or the resource is entirely publicly + available over all accepted methods, the server MAY ignore the + Authorization header, and the client will presumably try again later. + + Example - forcing auth challenge with Authorization header + + >>Request + + PROPFIND /docs/ HTTP/1.1 + Host: www.example.com + Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ== + Content-type: application/xml; charset="utf-8" + Content-Length: xxxx + + [body omitted] + + +<span class="h2"><h2><a class="selflink" name="appendix-F" href="#appendix-F">Appendix F</a>. Summary of Changes from <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a></h2></span> + + This section lists major changes between this document and <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a>, + starting with those that are likely to result in implementation + changes. Servers will advertise support for all changes in this + specification by returning the compliance class "3" in the DAV + response header (see Sections <a href="#section-10.1">10.1</a> and <a href="#section-18.3">18.3</a>). + +<span class="h1"><h1><a class="selflink" name="appendix-F.1" href="#appendix-F.1">F.1</a>. Changes for Both Client and Server Implementations</h1></span> + + Collections and Namespace Operations + + o The semantics of PROPFIND 'allprop' (<a href="#section-9.1">Section 9.1</a>) have been + relaxed so that servers return results including, at a minimum, + the live properties defined in this specification, but not + necessarily return other live properties. The 'allprop' directive + therefore means something more like "return all properties that + are supposed to be returned when 'allprop' is requested" -- a set + of properties that may include custom properties and properties + defined in other specifications if those other specifications so + require. Related to this, 'allprop' requests can now be extended + with the 'include' syntax to include specific named properties, + + + +<span class="grey">Dusseault Standards Track [Page 123]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-124" id="page-124" href="#page-124" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + thereby avoiding additional requests due to changed 'allprop' + semantics. + + o Servers are now allowed to reject PROPFIND requests with Depth: + Infinity. Clients that used this will need to be able to do a + series of Depth:1 requests instead. + + o Multi-Status response bodies now can transport the value of HTTP's + Location response header in the new 'location' element. Clients + may use this to avoid additional roundtrips to the server when + there is a 'response' element with a 3xx status (see + <a href="#section-14.24">Section 14.24</a>). + + o The definition of COPY has been relaxed so that it doesn't require + servers to first delete the target resources anymore (this was a + known incompatibility with [<a href="http://tools.ietf.org/html/rfc3253" title="" versioning extensions to webdav distributed authoring and>RFC3253</a>]). See <a href="#section-9.8">Section 9.8</a>. + + Headers and Marshalling + + o The Destination and If request headers now allow absolute paths in + addition to full URIs (see <a href="#section-8.3">Section 8.3</a>). This may be useful for + clients operating through a reverse proxy that does rewrite the + Host request header, but not WebDAV-specific headers. + + o This specification adopts the error marshalling extensions and the + "precondition/postcondition" terminology defined in [<a href="http://tools.ietf.org/html/rfc3253" title="" versioning extensions to webdav distributed authoring and>RFC3253</a>] (see + <a href="#section-16">Section 16</a>). Related to that, it adds the "error" XML element + inside multistatus response bodies (see <a href="#section-14.5">Section 14.5</a>, however note + that it uses a format different from the one recommended in <a href="http://tools.ietf.org/html/rfc3253">RFC</a> + <a href="http://tools.ietf.org/html/rfc3253">3253</a>). + + o Senders and recipients are now required to support the UTF-16 + character encoding in XML message bodies (see <a href="#section-19">Section 19</a>). + + o Clients are now required to send the Depth header on PROPFIND + requests, although servers are still encouraged to support clients + that don't. + + Locking + + o <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a>'s concept of "lock-null resources" (LNRs) has been + replaced by a simplified approach, the "locked empty resources" + (see <a href="#section-7.3">Section 7.3</a>). There are some aspects of lock-null resources + clients cannot rely on anymore, namely, the ability to use them to + create a locked collection or the fact that they disappear upon + UNLOCK when no PUT or MKCOL request was issued. Note that servers + are still allowed to implement LNRs as per <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a>. + + + + +<span class="grey">Dusseault Standards Track [Page 124]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-125" id="page-125" href="#page-125" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + o There is no implicit refresh of locks anymore. Locks are only + refreshed upon explicit request (see <a href="#section-9.10.2">Section 9.10.2</a>). + + o Clarified that the DAV:owner value supplied in the LOCK request + must be preserved by the server just like a dead property + (<a href="#section-14.17">Section 14.17</a>). Also added the DAV:lockroot element + (<a href="#section-14.12">Section 14.12</a>), which allows clients to discover the root of + lock. + +<span class="h1"><h1><a class="selflink" name="appendix-F.2" href="#appendix-F.2">F.2</a>. Changes for Server Implementations</h1></span> + + Collections and Namespace Operations + + o Due to interoperability problems, allowable formats for contents + of 'href' elements in multistatus responses have been limited (see + <a href="#section-8.3">Section 8.3</a>). + + o Due to lack of implementation, support for the 'propertybehavior' + request body for COPY and MOVE has been removed. Instead, + requirements for property preservation have been clarified (see + Sections <a href="#section-9.8">9.8</a> and <a href="#section-9.9">9.9</a>). + + Properties + + o Strengthened server requirements for storage of property values, + in particular persistence of language information (xml:lang), + whitespace, and XML namespace information (see <a href="#section-4.3">Section 4.3</a>). + + o Clarified requirements on which properties should be writable by + the client; in particular, setting "DAV:displayname" should be + supported by servers (see <a href="#section-15">Section 15</a>). + + o Only '<a href="http://tools.ietf.org/html/rfc1123">rfc1123</a>-date' productions are legal as values for DAV: + getlastmodified (see <a href="#section-15.7">Section 15.7</a>). + + Headers and Marshalling + + o Servers are now required to do authorization checks before + processing conditional headers (see <a href="#section-8.5">Section 8.5</a>). + + Locking + + o Strengthened requirement to check identity of lock creator when + accessing locked resources (see <a href="#section-6.4">Section 6.4</a>). Clients should be + aware that lock tokens returned to other principals can only be + used to break a lock, if at all. + + + + + +<span class="grey">Dusseault Standards Track [Page 125]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-126" id="page-126" href="#page-126" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + + o <a href="http://tools.ietf.org/html/rfc2518#section-8.10.4">Section 8.10.4 of [RFC2518]</a> incorrectly required servers to return + a 409 status where a 207 status was really appropriate. This has + been corrected (<a href="#section-9.10">Section 9.10</a>). + +<span class="h1"><h1><a class="selflink" name="appendix-F.3" href="#appendix-F.3">F.3</a>. Other Changes</h1></span> + + The definition of collection state has been fixed so it doesn't vary + anymore depending on the Request-URI (see <a href="#section-5.2">Section 5.2</a>). + + The DAV:source property introduced in <a href="http://tools.ietf.org/html/rfc2518#section-4.6">Section 4.6 of [RFC2518]</a> was + removed due to lack of implementation experience. + + The DAV header now allows non-IETF extensions through URIs in + addition to compliance class tokens. It also can now be used in + requests, although this specification does not define any associated + semantics for the compliance classes defined in here (see + <a href="#section-10.1">Section 10.1</a>). + + In <a href="http://tools.ietf.org/html/rfc2518">RFC 2518</a>, the definition of the Depth header (<a href="#section-9.2">Section 9.2</a>) + required that, by default, request headers would be applied to each + resource in scope. Based on implementation experience, the default + has now been reversed (see <a href="#section-10.2">Section 10.2</a>). + + The definitions of HTTP status code 102 (<a href="http://tools.ietf.org/html/rfc2518#section-10.1">[RFC2518], Section 10.1</a>) and + the Status-URI response header (<a href="#section-9.7">Section 9.7</a>) have been removed due to + lack of implementation. + + The TimeType format used in the Timeout request header and the + "timeout" XML element used to be extensible. Now, only the two + formats defined by this specification are allowed (see <a href="#section-10.7">Section 10.7</a>). + +Author's Address + + Lisa Dusseault (editor) + CommerceNet + 2064 Edgewood Dr. + Palo Alto, CA 94303 + US + + EMail: ldusseault@commerce.net + + + + + + + + + + + +<span class="grey">Dusseault Standards Track [Page 126]</span> +</pre><!--NewPage--><pre class="newpage"><a name="page-127" id="page-127" href="#page-127" class="invisible"> </a> +<span class="grey"><a href="#">RFC 4918</a> WebDAV June 2007</span> + + +Full Copyright Statement + + Copyright (C) The IETF Trust (2007). + + This document is subject to the rights, licenses and restrictions + contained in <a href="http://tools.ietf.org/html/bcp78">BCP 78</a>, and except as set forth therein, the authors + retain all their rights. + + This document and the information contained herein are provided on an + "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS + OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND + THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS + OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF + THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED + WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + +Intellectual Property + + The IETF takes no position regarding the validity or scope of any + Intellectual Property Rights or other rights that might be claimed to + pertain to the implementation or use of the technology described in + this document or the extent to which any license under such rights + might or might not be available; nor does it represent that it has + made any independent effort to identify any such rights. Information + on the procedures with respect to rights in RFC documents can be + found in <a href="http://tools.ietf.org/html/bcp78">BCP 78</a> and <a href="http://tools.ietf.org/html/bcp79">BCP 79</a>. + + Copies of IPR disclosures made to the IETF Secretariat and any + assurances of licenses to be made available, or the result of an + attempt made to obtain a general license or permission for the use of + such proprietary rights by implementers or users of this + specification can be obtained from the IETF on-line IPR repository at + <a href="http://www.ietf.org/ipr">http://www.ietf.org/ipr</a>. + + The IETF invites any interested party to bring to its attention any + copyrights, patents or patent applications, or other proprietary + rights that may cover technology that may be required to implement + this standard. Please address the information to the IETF at + ietf-ipr@ietf.org. + +Acknowledgement + + Funding for the RFC Editor function is currently provided by the + Internet Society. + + + + + + + +Dusseault Standards Track [Page 127] + +</pre><br> +<span class="noprint"><small><small>Html markup produced by rfcmarkup 1.109, available from +<a href="https://tools.ietf.org/tools/rfcmarkup/">https://tools.ietf.org/tools/rfcmarkup/</a> +</small></small></span> + +</body></html>
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