feat: implement PatchOp.patch

Author: azmeuk

doc/changelog.rst

@@ -7,6 +7,7 @@ Changelog
 Added
 ^^^^^
 - Proper path validation for :attr:`~scim2_models.SearchRequest.attributes`, :attr:`~scim2_models.SearchRequest.excluded_attributes` and :attr:`~scim2_models.SearchRequest.sort_by`.
+- Implement :meth:`~scim2_models.PatchOp.patch`
 
 Fixed
 ^^^^^

doc/tutorial.rst

@@ -403,9 +403,49 @@ This can be used by client applications that intends to dynamically discover ser
           :language: json
           :caption: schema-group.json
 
-Bulk and Patch operations
-=========================
+Patch operations
+================
+
+:class:`~scim2_models.PatchOp` allows you to apply patch operations to modify SCIM resources.
+The :meth:`~scim2_models.PatchOp.patch` method applies operations in sequence and returns whether the resource was modified. The return code is a boolean indicating whether the object have been modified by the operations.
+
+.. note::
+   :class:`~scim2_models.PatchOp` takes a type parameter that should be the class of the resource
+   that is expected to be patched.
+
+.. code-block:: python
+
+    >>> from scim2_models import User, PatchOp, PatchOperation
+    >>> user = User(user_name="john.doe", nick_name="Johnny")
+
+    >>> payload = {
+    ...   "schemas": ["urn:ietf:params:scim:api:messages:2.0:PatchOp"],
+    ...   "Operations": [
+    ...     {"op": "replace", "path": "nickName", "value": "John" },
+    ...     {"op": "add", "path": "emails", "value": [{"value": "[email protected]"}]},
+    ...   ]
+    ... }
+    >>> patch = PatchOp[User].model_validate(
+    ...     payload, scim_ctx=Context.RESOURCE_PATCH_REQUEST
+    ... )
+
+    >>> modified = patch.patch(user)
+    >>> print(modified)
+    True
+    >>> print(user.nick_name)
+    John
+    >>> print(user.emails[0].value)
+    john@example.com
+
+.. warning::
+
+   Patch operations are validated in the :attr:`~scim2_models.Context.RESOURCE_PATCH_REQUEST`
+   context. Make sure to validate patch operations with the correct context to
+   ensure proper validation of mutability and required constraints.
+
+Bulk operations
+===============
 
 .. todo::
 
-   Bulk and Patch operations are not implemented yet, but any help is welcome!
+   Bulk operations are not implemented yet, but any help is welcome!

scim2_models/rfc7644/message.py

@@ -114,12 +114,6 @@ def __new__(
 
 def get_resource_class(obj) -> Optional[type[Resource]]:
     """Extract the resource class from generic type parameter."""
-    metadata = getattr(obj.__class__, "__pydantic_generic_metadata__", None)
-    if not metadata or not metadata.get("args"):
-        return None
-
+    metadata = getattr(obj.__class__, "__pydantic_generic_metadata__", {"args": [None]})
     resource_class = metadata["args"][0]
-    if isinstance(resource_class, type) and issubclass(resource_class, Resource):
-        return resource_class
-
-    return None
+    return resource_class