File Content: jsonpatch.py # -*- coding: utf-8 -*- # # python-json-patch - An implementation of the JSON Patch format # https://github.com/stefankoegl/python-json-patch # # Copyright (c) 2011 Stefan Kögl <stefan@skoegl.net> # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # 3. The name of the author may not be used to endorse or promote products # derived from this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # """ Apply JSON-Patches (RFC 6902) """ from __future__ import unicode_literals import collections import copy import functools import inspect import itertools import json import sys from jsonpointer import JsonPointer, JsonPointerException _ST_ADD = 0 _ST_REMOVE = 1 try: from collections.abc import MutableMapping, MutableSequence except ImportError: from collections import MutableMapping, MutableSequence str = unicode # Will be parsed by setup.py to determine package metadata __author__ = 'Stefan Kögl <stefan@skoegl.net>' __version__ = '1.21' __website__ = 'https://github.com/stefankoegl/python-json-patch' __license__ = 'Modified BSD License' # pylint: disable=E0611,W0404 if sys.version_info >= (3, 0): basestring = (bytes, str) # pylint: disable=C0103,W0622 class JsonPatchException(Exception): """Base Json Patch exception""" class InvalidJsonPatch(JsonPatchException): """ Raised if an invalid JSON Patch is created """ class JsonPatchConflict(JsonPatchException): """Raised if patch could not be applied due to conflict situation such as: - attempt to add object key then it already exists; - attempt to operate with nonexistence object key; - attempt to insert value to array at position beyond of it size; - etc. """ class JsonPatchTestFailed(JsonPatchException, AssertionError): """ A Test operation failed """ def multidict(ordered_pairs): """Convert duplicate keys values to lists.""" # read all values into lists mdict = collections.defaultdict(list) for key, value in ordered_pairs: mdict[key].append(value) return dict( # unpack lists that have only 1 item (key, values[0] if len(values) == 1 else values) for key, values in mdict.items() ) # The "object_pairs_hook" parameter is used to handle duplicate keys when # loading a JSON object. _jsonloads = functools.partial(json.loads, object_pairs_hook=multidict) def apply_patch(doc, patch, in_place=False): """Apply list of patches to specified json document. :param doc: Document object. :type doc: dict :param patch: JSON patch as list of dicts or raw JSON-encoded string. :type patch: list or str :param in_place: While :const:`True` patch will modify target document. By default patch will be applied to document copy. :type in_place: bool :return: Patched document object. :rtype: dict >>> doc = {'foo': 'bar'} >>> patch = [{'op': 'add', 'path': '/baz', 'value': 'qux'}] >>> other = apply_patch(doc, patch) >>> doc is not other True >>> other == {'foo': 'bar', 'baz': 'qux'} True >>> patch = [{'op': 'add', 'path': '/baz', 'value': 'qux'}] >>> apply_patch(doc, patch, in_place=True) == {'foo': 'bar', 'baz': 'qux'} True >>> doc == other True """ if isinstance(patch, basestring): patch = JsonPatch.from_string(patch) else: patch = JsonPatch(patch) return patch.apply(doc, in_place) def make_patch(src, dst): """Generates patch by comparing of two document objects. Actually is a proxy to :meth:`JsonPatch.from_diff` method. :param src: Data source document object. :type src: dict :param dst: Data source document object. :type dst: dict >>> src = {'foo': 'bar', 'numbers': [1, 3, 4, 8]} >>> dst = {'baz': 'qux', 'numbers': [1, 4, 7]} >>> patch = make_patch(src, dst) >>> new = patch.apply(src) >>> new == dst True """ return JsonPatch.from_diff(src, dst) class JsonPatch(object): """A JSON Patch is a list of Patch Operations. >>> patch = JsonPatch([ ... {'op': 'add', 'path': '/foo', 'value': 'bar'}, ... {'op': 'add', 'path': '/baz', 'value': [1, 2, 3]}, ... {'op': 'remove', 'path': '/baz/1'}, ... {'op': 'test', 'path': '/baz', 'value': [1, 3]}, ... {'op': 'replace', 'path': '/baz/0', 'value': 42}, ... {'op': 'remove', 'path': '/baz/1'}, ... ]) >>> doc = {} >>> result = patch.apply(doc) >>> expected = {'foo': 'bar', 'baz': [42]} >>> result == expected True JsonPatch object is iterable, so you could easily access to each patch statement in loop: >>> lpatch = list(patch) >>> expected = {'op': 'add', 'path': '/foo', 'value': 'bar'} >>> lpatch[0] == expected True >>> lpatch == patch.patch True Also JsonPatch could be converted directly to :class:`bool` if it contains any operation statements: >>> bool(patch) True >>> bool(JsonPatch([])) False This behavior is very handy with :func:`make_patch` to write more readable code: >>> old = {'foo': 'bar', 'numbers': [1, 3, 4, 8]} >>> new = {'baz': 'qux', 'numbers': [1, 4, 7]} >>> patch = make_patch(old, new) >>> if patch: ... # document have changed, do something useful ... patch.apply(old) #doctest: +ELLIPSIS {...} """ def __init__(self, patch): self.patch = patch self.operations = { 'remove': RemoveOperation, 'add': AddOperation, 'replace': ReplaceOperation, 'move': MoveOperation, 'test': TestOperation, 'copy': CopyOperation, } def __str__(self): """str(self) -> self.to_string()""" return self.to_string() def __bool__(self): return bool(self.patch) __nonzero__ = __bool__ def __iter__(self): return iter(self.patch) def __hash__(self): return hash(tuple(self._ops)) def __eq__(self, other): if not isinstance(other, JsonPatch): return False return self._ops == other._ops def __ne__(self, other): return not(self == other) @classmethod def from_string(cls, patch_str): """Creates JsonPatch instance from string source. :param patch_str: JSON patch as raw string. :type patch_str: str :return: :class:`JsonPatch` instance. """ patch = _jsonloads(patch_str) return cls(patch) @classmethod def from_diff(cls, src, dst, optimization=True): """Creates JsonPatch instance based on comparing of two document objects. Json patch would be created for `src` argument against `dst` one. :param src: Data source document object. :type src: dict :param dst: Data source document object. :type dst: dict :return: :class:`JsonPatch` instance. >>> src = {'foo': 'bar', 'numbers': [1, 3, 4, 8]} >>> dst = {'baz': 'qux', 'numbers': [1, 4, 7]} >>> patch = JsonPatch.from_diff(src, dst) >>> new = patch.apply(src) >>> new == dst True """ builder = DiffBuilder() builder._compare_values('', None, src, dst) ops = list(builder.execute()) return cls(ops) def to_string(self): """Returns patch set as JSON string.""" return json.dumps(self.patch) @property def _ops(self): return tuple(map(self._get_operation, self.patch)) def apply(self, obj, in_place=False): """Applies the patch to given object. :param obj: Document object. :type obj: dict :param in_place: Tweaks way how patch would be applied - directly to specified `obj` or to his copy. :type in_place: bool :return: Modified `obj`. """ if not in_place: obj = copy.deepcopy(obj) for operation in self._ops: obj = operation.apply(obj) return obj def _get_operation(self, operation): if 'op' not in operation: raise InvalidJsonPatch("Operation does not contain 'op' member") op = operation['op'] if not isinstance(op, basestring): raise InvalidJsonPatch("Operation must be a string") if op not in self.operations: raise InvalidJsonPatch("Unknown operation {0!r}".format(op)) cls = self.operations[op] return cls(operation) class PatchOperation(object): """A single operation inside a JSON Patch.""" def __init__(self, operation): self.location = operation['path'] self.pointer = JsonPointer(self.location) self.operation = operation def apply(self, obj): """Abstract method that applies patch operation to specified object.""" raise NotImplementedError('should implement patch operation.') def __hash__(self): return hash(frozenset(self.operation.items())) def __eq__(self, other): if not isinstance(other, PatchOperation): return False return self.operation == other.operation def __ne__(self, other): return not(self == other) @property def path(self): return '/'.join(self.pointer.parts[:-1]) @property def key(self): try: return int(self.pointer.parts[-1]) except ValueError: return self.pointer.parts[-1] @key.setter def key(self, value): self.pointer.parts[-1] = str(value) self.location = self.pointer.path self.operation['path'] = self.location class RemoveOperation(PatchOperation): """Removes an object property or an array element.""" def apply(self, obj): subobj, part = self.pointer.to_last(obj) try: del subobj[part] except (KeyError, IndexError) as ex: msg = "can't remove non-existent object '{0}'".format(part) raise JsonPatchConflict(msg) return obj def _on_undo_remove(self, path, key): if self.path == path: if self.key >= key: self.key += 1 else: key -= 1 return key def _on_undo_add(self, path, key): if self.path == path: if self.key > key: self.key -= 1 else: key -= 1 return key class AddOperation(PatchOperation): """Adds an object property or an array element.""" def apply(self, obj): try: value = self.operation["value"] except KeyError as ex: raise InvalidJsonPatch( "The operation does not contain a 'value' member") subobj, part = self.pointer.to_last(obj) if isinstance(subobj, MutableSequence): if part == '-': subobj.append(value) # pylint: disable=E1103 elif part > len(subobj) or part < 0: raise JsonPatchConflict("can't insert outside of list") else: subobj.insert(part, value) # pylint: disable=E1103 elif isinstance(subobj, MutableMapping): if part is None: obj = value # we're replacing the root else: subobj[part] = value else: raise TypeError("invalid document type {0}".format(type(subobj))) return obj def _on_undo_remove(self, path, key): if self.path == path: if self.key > key: self.key += 1 else: key += 1 return key def _on_undo_add(self, path, key): if self.path == path: if self.key > key: self.key -= 1 else: key += 1 return key class ReplaceOperation(PatchOperation): """Replaces an object property or an array element by new value.""" def apply(self, obj): try: value = self.operation["value"] except KeyError as ex: raise InvalidJsonPatch( "The operation does not contain a 'value' member") subobj, part = self.pointer.to_last(obj) if part is None: return value if isinstance(subobj, MutableSequence): if part > len(subobj) or part < 0: raise JsonPatchConflict("can't replace outside of list") elif isinstance(subobj, MutableMapping): if part not in subobj: msg = "can't replace non-existent object '{0}'".format(part) raise JsonPatchConflict(msg) else: raise TypeError("invalid document type {0}".format(type(subobj))) subobj[part] = value return obj def _on_undo_remove(self, path, key): return key def _on_undo_add(self, path, key): return key class MoveOperation(PatchOperation): """Moves an object property or an array element to new location.""" def apply(self, obj): try: from_ptr = JsonPointer(self.operation['from']) except KeyError as ex: raise InvalidJsonPatch( "The operation does not contain a 'from' member") subobj, part = from_ptr.to_last(obj) try: value = subobj[part] except (KeyError, IndexError) as ex: raise JsonPatchConflict(str(ex)) # If source and target are equal, this is a no-op if self.pointer == from_ptr: return obj if isinstance(subobj, MutableMapping) and \ self.pointer.contains(from_ptr): raise JsonPatchConflict('Cannot move values into its own children') obj = RemoveOperation({ 'op': 'remove', 'path': self.operation['from'] }).apply(obj) obj = AddOperation({ 'op': 'add', 'path': self.location, 'value': value }).apply(obj) return obj @property def from_path(self): from_ptr = JsonPointer(self.operation['from']) return '/'.join(from_ptr.parts[:-1]) @property def from_key(self): from_ptr = JsonPointer(self.operation['from']) try: return int(from_ptr.parts[-1]) except TypeError: return from_ptr.parts[-1] @from_key.setter def from_key(self, value): from_ptr = JsonPointer(self.operation['from']) from_ptr.parts[-1] = str(value) self.operation['from'] = from_ptr.path def _on_undo_remove(self, path, key): if self.from_path == path: if self.from_key >= key: self.from_key += 1 else: key -= 1 if self.path == path: if self.key > key: self.key += 1 else: key += 1 return key def _on_undo_add(self, path, key): if self.from_path == path: if self.from_key > key: self.from_key -= 1 else: key -= 1 if self.path == path: if self.key > key: self.key -= 1 else: key += 1 return key class TestOperation(PatchOperation): """Test value by specified location.""" def apply(self, obj): try: subobj, part = self.pointer.to_last(obj) if part is None: val = subobj else: val = self.pointer.walk(subobj, part) except JsonPointerException as ex: raise JsonPatchTestFailed(str(ex)) try: value = self.operation['value'] except KeyError as ex: raise InvalidJsonPatch( "The operation does not contain a 'value' member") if val != value: msg = '{0} ({1}) is not equal to tested value {2} ({3})' raise JsonPatchTestFailed(msg.format(val, type(val), value, type(value))) return obj class CopyOperation(PatchOperation): """ Copies an object property or an array element to a new location """ def apply(self, obj): try: from_ptr = JsonPointer(self.operation['from']) except KeyError as ex: raise InvalidJsonPatch( "The operation does not contain a 'from' member") subobj, part = from_ptr.to_last(obj) try: value = copy.deepcopy(subobj[part]) except (KeyError, IndexError) as ex: raise JsonPatchConflict(str(ex)) obj = AddOperation({ 'op': 'add', 'path': self.location, 'value': value }).apply(obj) return obj class DiffBuilder(object): def __init__(self): self.index_storage = [{}, {}] self.index_storage2 = [[], []] self.__root = root = [] root[:] = [root, root, None] def store_index(self, value, index, st): try: storage = self.index_storage[st] stored = storage.get(value) if stored is None: storage[value] = [index] else: storage[value].append(index) except TypeError: self.index_storage2[st].append((value, index)) def take_index(self, value, st): try: stored = self.index_storage[st].get(value) if stored: return stored.pop() except TypeError: storage = self.index_storage2[st] for i in range(len(storage)-1, -1, -1): if storage[i][0] == value: return storage.pop(i)[1] def insert(self, op): root = self.__root last = root[0] last[1] = root[0] = [last, root, op] return root[0] def remove(self, index): link_prev, link_next, _ = index link_prev[1] = link_next link_next[0] = link_prev index[:] = [] def iter_from(self, start): root = self.__root curr = start[1] while curr is not root: yield curr[2] curr = curr[1] def __iter__(self): root = self.__root curr = root[1] while curr is not root: yield curr[2] curr = curr[1] def execute(self): root = self.__root curr = root[1] while curr is not root: if curr[1] is not root: op_first, op_second = curr[2], curr[1][2] if op_first.location == op_second.location and \ type(op_first) == RemoveOperation and \ type(op_second) == AddOperation: yield ReplaceOperation({ 'op': 'replace', 'path': op_second.location, 'value': op_second.operation['value'], }).operation curr = curr[1][1] continue yield curr[2].operation curr = curr[1] def _item_added(self, path, key, item): index = self.take_index(item, _ST_REMOVE) if index is not None: op = index[2] if type(op.key) == int: for v in self.iter_from(index): op.key = v._on_undo_remove(op.path, op.key) self.remove(index) if op.location != _path_join(path, key): new_op = MoveOperation({ 'op': 'move', 'from': op.location, 'path': _path_join(path, key), }) self.insert(new_op) else: new_op = AddOperation({ 'op': 'add', 'path': _path_join(path, key), 'value': item, }) new_index = self.insert(new_op) self.store_index(item, new_index, _ST_ADD) def _item_removed(self, path, key, item): new_op = RemoveOperation({ 'op': 'remove', 'path': _path_join(path, key), }) index = self.take_index(item, _ST_ADD) new_index = self.insert(new_op) if index is not None: op = index[2] if type(op.key) == int: for v in self.iter_from(index): op.key = v._on_undo_add(op.path, op.key) self.remove(index) if new_op.location != op.location: new_op = MoveOperation({ 'op': 'move', 'from': new_op.location, 'path': op.location, }) new_index[2] = new_op else: self.remove(new_index) else: self.store_index(item, new_index, _ST_REMOVE) def _item_replaced(self, path, key, item): self.insert(ReplaceOperation({ 'op': 'replace', 'path': _path_join(path, key), 'value': item, })) def _compare_dicts(self, path, src, dst): src_keys = set(src.keys()) dst_keys = set(dst.keys()) added_keys = dst_keys - src_keys removed_keys = src_keys - dst_keys for key in removed_keys: self._item_removed(path, str(key), src[key]) for key in added_keys: self._item_added(path, str(key), dst[key]) for key in src_keys & dst_keys: self._compare_values(path, key, src[key], dst[key]) def _compare_lists(self, path, src, dst): len_src, len_dst = len(src), len(dst) max_len = max(len_src, len_dst) min_len = min(len_src, len_dst) for key in range(max_len): if key < min_len: old, new = src[key], dst[key] if old == new: continue elif isinstance(old, MutableMapping) and \ isinstance(new, MutableMapping): self._compare_dicts(_path_join(path, key), old, new) elif isinstance(old, MutableSequence) and \ isinstance(new, MutableSequence): self._compare_lists(_path_join(path, key), old, new) else: self._item_removed(path, key, old) self._item_added(path, key, new) elif len_src > len_dst: self._item_removed(path, len_dst, src[key]) else: self._item_added(path, key, dst[key]) def _compare_values(self, path, key, src, dst): if src == dst: return elif isinstance(src, MutableMapping) and \ isinstance(dst, MutableMapping): self._compare_dicts(_path_join(path, key), src, dst) elif isinstance(src, MutableSequence) and \ isinstance(dst, MutableSequence): self._compare_lists(_path_join(path, key), src, dst) else: self._item_replaced(path, key, dst) def _path_join(path, key): if key is None: return path return path + '/' + str(key).replace('~', '~0').replace('/', '~1') Submit