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Diffstat (limited to 'json_diff.py')
| -rw-r--r-- | json_diff.py | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/json_diff.py b/json_diff.py new file mode 100644 index 0000000..1dadbf5 --- /dev/null +++ b/json_diff.py @@ -0,0 +1,154 @@ +#!/usr/bin/python +# -*- coding: utf-8 -*- +""" +Script for comparing two objects +""" +import json +from optparse import OptionParser +import logging + +logging.basicConfig(format='%(levelname)s:%(funcName)s:%(message)s', level=logging.INFO) + +class Comparator(object): + """ + Main workhorse, the object itself + """ + def __init__(self, fn1=None, fn2=None, excluded_attrs=()): + if fn1: + self.obj1 = json.load(fn1) + if fn2: + self.obj2 = json.load(fn2) + self.excluded_attributes = excluded_attrs + if (fn1 and fn2): + logging.debug("self.obj1 = %s\nself.obj2 = %s\nself.excluded_attrs = %s", \ + (self.obj1, self.obj2, self.excluded_attributes)) + + @staticmethod + def _get_keys(obj): + """ + Getter for the current object's keys. + """ + out = set() + for key in obj.keys(): + out.add(key) + return out + + @staticmethod + 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)) + + def _compare_arrays(self, old_arr, new_arr): + inters = min(old_arr, new_arr) + + result = { + u"append": {}, + u"remove": {}, + u"update": {} + } + for idx in range(len(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 (self._is_scalar(old_arr)): + if old_arr[idx] != new_arr[idx]: + result['update'][idx] = new_arr[idx] + # 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 + + # Clear out unused inters in result + out_result = {} + for key in result: + if len(result[key]) > 0: + out_result[key] = result[key] + + 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 = self._get_keys(old_obj) + if new_obj and len(new_obj) > 0: + new_keys = self._get_keys(new_obj) + + keys = old_keys | new_keys + + result = { + u"append": {}, + u"remove": {}, + u"update": {} + } + for name in keys: + # Explicitly excluded arguments + if (name in self.excluded_attributes): + continue + # 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] + # changed objects, new value is new_obj + elif (type(old_obj[name]) != type(new_obj[name])): + result['update'][name] = new_obj[name] + # last simple variant ... scalars + elif (self._is_scalar(old_obj[name])): + if old_obj[name] != new_obj[name]: + result['update'][name] = new_obj[name] + # now arrays + 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 + # and now nested dicts + 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 + + # 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" + parser = OptionParser(usage=usage) + parser.add_option("-x", "--exclude", + action="append", dest="exclude", metavar="ATTR", default=[], + help="attributes which should be ignored when comparing") + (options, args) = parser.parse_args() + logging.debug("options = %s", str(options)) + logging.debug("args = %s", str(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) + print json.dumps(diff.compare_dicts(), indent=4, ensure_ascii=False)
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