Tutorial

Please refer to RFC 6902 for the exact patch syntax.

Creating a Patch

Patches can be created in two ways. One way is to explicitly create a JsonPatch object from a list of operations. For convenience, the method JsonPatch.from_string() accepts a string, parses it and constructs the patch object from it.

>>> import jsonpatch
>>> patch = jsonpatch.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'},
])

# or equivalently
>>> patch = jsonpatch.JsonPatch.from_string('[{"op": "add", ....}]')

Another way is to diff two objects.

>>> src = {'foo': 'bar', 'numbers': [1, 3, 4, 8]}
>>> dst = {'baz': 'qux', 'numbers': [1, 4, 7]}
>>> patch = jsonpatch.JsonPatch.from_diff(src, dst)

# or equivalently
>>> patch = jsonpatch.make_patch(src, dst)

Applying a Patch

A patch is always applied to an object.

>>> doc = {}
>>> result = patch.apply(doc)
{'foo': 'bar', 'baz': [42]}

The apply method returns a new object as a result. If in_place=True the object is modified in place.

If a patch is only used once, it is not necessary to create a patch object explicitly.

>>> obj = {'foo': 'bar'}

# from a patch string
>>> patch = '[{"op": "add", "path": "/baz", "value": "qux"}]'
>>> res = jsonpatch.apply_patch(obj, patch)

# or from a list
>>> patch = [{'op': 'add', 'path': '/baz', 'value': 'qux'}]
>>> res = jsonpatch.apply_patch(obj, patch)