#!/usr/bin/python
# -*- coding: utf-8 -*-
"""
Script for comparing two objects
Copyright (c) 2011, Red Hat Corp.
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""
from __future__ import division, absolute_import, print_function, unicode_literals
import json, sys
# import pdb
import logging
from optparse import OptionParser
__author__ = "Matěj Cepl"
__version__ = "0.1.0"
logging.basicConfig(format='%(levelname)s:%(funcName)s:%(message)s', level=logging.DEBUG)
STYLE_MAP = {
"_append": "append_class",
"_remove": "remove_class",
"_update": "update_class"
}
INTERNAL_KEYS = set(STYLE_MAP.keys())
LEVEL_INDENT = " "
out_str_template = """
%s
%s
%s
"""
# I would love to have better solution for this ...
if sys.version_info[0] == 3: unicode = str
def is_scalar(value):
"""
Primitive version, relying on the fact that JSON cannot
contain any more complicated data structures.
"""
return not isinstance(value, (list, tuple, dict))
class HTMLFormatter(object):
def __init__(self, diff_object):
self.diff = diff_object
def _generate_page(self, in_dict, title="json_diff result"):
out_str = out_str_template % (title, title,
self._format_dict(in_dict))
out_str += """
"""
return out_str
def _format_item(self, item, index, typch, level=0):
level_str = ("" + LEVEL_INDENT + " | ") * level
if is_scalar(item):
out_str = ("\n %s| %s = %s | \n
\n" %
(level_str, STYLE_MAP[typch], index, unicode(item)))
elif isinstance(item, (list, tuple)):
out_str = self._format_array(item, typch, level+1)
else:
out_str = self._format_dict(item, typch, level+1)
return out_str.strip()
def _format_array(self, diff_array, typch, level=0):
out_str = ""
for index in range(len(diff_array)):
out_str += self._format_item(diff_array[index], index, typch, level)
return out_str.strip()
# doesn't have level and neither concept of it, much
def _format_dict(self, diff_dict, typch="unknown_change", level=0):
out_str = ""
# For all STYLE_MAP keys which are present in diff_dict
for typechange in set(diff_dict.keys()) & INTERNAL_KEYS:
out_str += self._format_dict(diff_dict[typechange], typechange, level)
# For all other non-internal keys
for variable in set(diff_dict.keys()) - INTERNAL_KEYS:
out_str += self._format_item(diff_dict[variable], variable, typch, level)
return out_str.strip()
def __str__(self):
return self._generate_page(self.diff)
class BadJSONError(ValueError):
pass
class Comparator(object):
"""
Main workhorse, the object itself
"""
def __init__(self, fn1=None, fn2=None, included_attrs=(), excluded_attrs=()):
self.obj1 = None
self.obj2 = None
if fn1:
try:
self.obj1 = json.load(fn1)
except (TypeError, OverflowError, ValueError) as exc:
raise BadJSONError("Cannot decode object from JSON.\n%s" % unicode(exc))
if fn2:
try:
self.obj2 = json.load(fn2)
except (TypeError, OverflowError, ValueError) as exc:
raise BadJSONError("Cannot decode object from JSON\n%s" % unicode(exc))
self.excluded_attributes = excluded_attrs
self.included_attributes = included_attrs
if self.obj1:
logging.debug("self.obj1:\n%s\n", json.dumps(self.obj1, indent=4))
if self.obj2:
logging.debug("self.obj2:\n%s\n", json.dumps(self.obj2, indent=4))
def _compare_scalars(self, old, new, name=None):
"""
Be careful with the result of this function. Negative answer from this function
is really None, not False, so deciding based on the return value like in
if self._compare_scalars(...):
leads to wrong answer (it should be if self._compare_scalars(...) is not None:)
"""
# Explicitly excluded arguments
logging.debug("Comparing scalars %s and %s", old, new)
if ((self.included_attributes and (name not in self.included_attributes)) or
(name in self.excluded_attributes)):
return None
elif old != new:
logging.debug("Comparing result (name=%s) is %s", name, new)
return new
else:
logging.debug("Comparing result (name=%s) is None", name)
return None
def _compare_arrays(self, old_arr, new_arr):
"""
simpler version of compare_dicts; just an internal method, becase
it could never be called from outside.
We have it guaranteed that both new_arr and old_arr are of type list.
"""
inters = min(len(old_arr), len(new_arr)) # this is the smaller length
result = {
"_append": {},
"_remove": {},
"_update": {}
}
for idx in range(inters):
# changed objects, new value is new_arr
if (type(old_arr[idx]) != type(new_arr[idx])):
result['_update'][idx] = new_arr[idx]
# another simple variant ... scalars
elif (is_scalar(old_arr[idx])):
scalar_diff = self._compare_scalars(old_arr[idx], new_arr[idx])
if scalar_diff is not None:
result['_update'][idx] = scalar_diff
# recursive arrays
elif (isinstance(old_arr[idx], list)):
res_arr = self._compare_arrays(old_arr[idx],
new_arr[idx])
if (len(res_arr) > 0):
result['_update'][idx] = res_arr
# and now nested dicts
elif isinstance(old_arr[idx], dict):
res_dict = self.compare_dicts(old_arr[idx], new_arr[idx])
if (len(res_dict) > 0):
result['_update'][idx] = res_dict
# the rest of the larger array
if (inters == len(old_arr)):
for idx in range(inters, len(new_arr)):
result['_append'][idx] = new_arr[idx]
else:
for idx in range(inters, len(old_arr)):
result['_remove'][idx] = old_arr[idx]
# Clear out unused keys in result
out_result = {}
for key in result:
if len(result[key]) > 0:
out_result[key] = result[key]
logging.debug("out_result = %s",
json.dumps(out_result, indent=4))
return out_result
def compare_dicts(self, old_obj=None, new_obj=None):
"""
The real workhorse
"""
if not old_obj and hasattr(self, "obj1"):
old_obj = self.obj1
if not new_obj and hasattr(self, "obj2"):
new_obj = self.obj2
old_keys = set()
new_keys = set()
if old_obj and len(old_obj) > 0:
old_keys = set(old_obj.keys())
if new_obj and len(new_obj) > 0:
new_keys = set(new_obj.keys())
keys = old_keys | new_keys
result = {
"_append": {},
"_remove": {},
"_update": {}
}
for name in keys:
# old_obj is missing
if name not in old_obj:
result['_append'][name] = new_obj[name]
# new_obj is missing
elif name not in new_obj:
result['_remove'][name] = old_obj[name]
# We want to go through the tree post-order
elif isinstance(old_obj[name], dict):
res_dict = self.compare_dicts(old_obj[name], new_obj[name])
if (len(res_dict) > 0):
result['_update'][name] = res_dict
# Now we are on the same level
# changed objects, new value is new_obj
elif (type(old_obj[name]) != type(new_obj[name])):
result['_update'][name] = new_obj[name]
# now arrays (we can be sure, that both old_obj and
# new_obj are of the same type)
elif (isinstance(old_obj[name], list)):
res_arr = self._compare_arrays(old_obj[name],
new_obj[name])
if (len(res_arr) > 0):
result['_update'][name] = res_arr
# the only thing remaining are scalars
else:
# Explicitly excluded arguments
res_scal = self._compare_scalars(old_obj[name], new_obj[name], name)
if res_scal is not None:
result['_update'][name] = res_scal
# Clear out unused keys in result
out_result = {}
for key in result:
if len(result[key]) > 0:
out_result[key] = result[key]
return out_result
if __name__ == "__main__":
usage = "usage: %prog [options] old.json new.json"
description = "Generates diff between two JSON files."
parser = OptionParser(usage=usage)
parser.add_option("-x", "--exclude",
action="append", dest="exclude", metavar="ATTR", default=[],
help="attributes which should be ignored when comparing")
parser.add_option("-i", "--include",
action="append", dest="include", metavar="ATTR", default=[],
help="attributes which should be exclusively used when comparing")
parser.add_option("-H", "--HTML",
action="store_true", dest="HTMLoutput", metavar="BOOL", default=False,
help="program should output to HTML report")
(options, args) = parser.parse_args()
if len(args) != 2:
parser.error("Script requires two positional arguments, names for old and new JSON file.")
diff = Comparator(file(args[0]), file(args[1]), options.exclude, options.include)
if options.HTMLoutput:
diff_res = diff.compare_dicts()
# logging.debug("diff_res:\n%s", json.dumps(diff_res, indent=True))
print(HTMLFormatter(diff_res))
else:
outs = json.dumps(diff.compare_dicts(), indent=4, ensure_ascii=False).encode("utf-8")
outs = "\n".join([line for line in outs.split("\n")])
print(outs)