// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package oauth2
import (
"errors"
"io"
"net/http"
"sync"
)
// Transport is an http.RoundTripper that makes OAuth 2.0 HTTP requests,
// wrapping a base RoundTripper and adding an Authorization header
// with a token from the supplied Sources.
//
// Transport is a low-level mechanism. Most code will use the
// higher-level Config.Client method instead.
type Transport struct {
// Source supplies the token to add to outgoing requests'
// Authorization headers.
Source TokenSource
// Base is the base RoundTripper used to make HTTP requests.
// If nil, http.DefaultTransport is used.
Base http.RoundTripper
mu sync.Mutex // guards modReq
modReq map[*http.Request]*http.Request // original -> modified
}
// RoundTrip authorizes and authenticates the request with an
// access token from Transport's Source.
func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
reqBodyClosed := false
if req.Body != nil {
defer func() {
if !reqBodyClosed {
req.Body.Close()
}
}()
}
if t.Source == nil {
return nil, errors.New("oauth2: Transport's Source is nil")
}
token, err := t.Source.Token()
if err != nil {
return nil, err
}
req2 := cloneRequest(req) // per RoundTripper contract
token.SetAuthHeader(req2)
t.setModReq(req, req2)
res, err := t.base().RoundTrip(req2)
// req.Body is assumed to have been closed by the base RoundTripper.
reqBodyClosed = true
if err != nil {
t.setModReq(req, nil)
return nil, err
}
res.Body = &onEOFReader{
rc: res.Body,
fn: func() { t.setModReq(req, nil) },
}
return res, nil
}
// CancelRequest cancels an in-flight request by closing its connection.
func (t *Transport) CancelRequest(req *http.Request) {
type canceler interface {
CancelRequest(*http.Request)
}
if cr, ok := t.base().(canceler); ok {
t.mu.Lock()
modReq := t.modReq[req]
delete(t.modReq, req)
t.mu.Unlock()
cr.CancelRequest(modReq)
}
}
func (t *Transport) base() http.RoundTripper {
if t.Base != nil {
return t.Base
}
return http.DefaultTransport
}
func (t *Transport) setModReq(orig, mod *http.Request) {
t.mu.Lock()
defer t.mu.Unlock()
if t.modReq == nil {
t.modReq = make(map[*http.Request]*http.Request)
}
if mod == nil {
delete(t.modReq, orig)
} else {
t.modReq[orig] = mod
}
}
// cloneRequest returns a clone of the provided *http.Request.
// The clone is a shallow copy of the struct and its Header map.
func cloneRequest(r *http.Request) *http.Request {
// shallow copy of the struct
r2 := new(http.Request)
*r2 = *r
// deep copy of the Header
r2.Header = make(http.Header, len(r.Header))
for k, s := range r.Header {
r2.Header[k] = append([]string(nil), s...)
}
return r2
}
type onEOFReader struct {
rc io.ReadCloser
fn func()
}
func (r *onEOFReader) Read(p []byte) (n int, err error) {
n, err = r.rc.Read(p)
if err == io.EOF {
r.runFunc()
}
return
}
func (r *onEOFReader) Close() error {
err := r.rc.Close()
r.runFunc()
return err
}
func (r *onEOFReader) runFunc() {
if fn := r.fn; fn != nil {
fn()
r.fn = nil
}
}
