Merge pull request #1009 from tfranzel/pydantic_blockers

Example Pydantic support

docs/blueprints.rst

@@ -146,4 +146,13 @@ django-parler-rest
 `django-parler-rest <https://github.com/django-parler/django-parler-rest>`_ integration for
 translation package `django-parler <https://github.com/django-parler/django-parler>`_.
 
-.. literalinclude:: blueprints/django_parler_rest.py
+.. literalinclude:: blueprints/django_parler_rest.py
+
+
+Pydantic
+--------
+
+Preliminary support for `Pydantic <https://github.com/pydantic/pydantic>`_  models. This may or may not
+end up in the main package. Catches decorated Pydantic classes and integrates their schema.
+
+.. literalinclude:: blueprints/pydantic.py

docs/blueprints/pydantic.py

@@ -0,0 +1,36 @@
+from drf_spectacular.extensions import OpenApiSerializerExtension
+from drf_spectacular.plumbing import ResolvedComponent
+
+
+class PydanticExtension(OpenApiSerializerExtension):
+    target_class = 'pydantic.BaseModel'
+    match_subclasses = True
+
+    def get_name(self, auto_schema, direction):
+        return self.target.__name__
+
+    def map_serializer(self, auto_schema, direction):
+        def translate_refs(obj, key=None):
+            if isinstance(obj, dict):
+                return {k: translate_refs(v, k) for k, v in obj.items()}
+            elif isinstance(obj, list):
+                return [translate_refs(i) for i in obj]
+            elif key == '$ref':
+                return obj.replace('#/definitions/', '#/components/schemas/')
+            else:
+                return obj
+
+        # let pydantic generate a JSON schema
+        schema = self.target.schema()
+
+        # pull out potential sub-schemas and put them into component section
+        for sub_name, sub_schema in schema.pop('definitions', {}).items():
+            component = ResolvedComponent(
+                name=sub_name,
+                type=ResolvedComponent.SCHEMA,
+                object=sub_name,
+                schema=translate_refs(sub_schema),
+            )
+            auto_schema.registry.register_on_missing(component)
+
+        return translate_refs(schema)

drf_spectacular/plumbing.py

@@ -146,8 +146,8 @@ def is_basic_type(obj, allow_none=True):
 def is_patched_serializer(serializer, direction):
     return bool(
         spectacular_settings.COMPONENT_SPLIT_PATCH
-        and serializer.partial
-        and not serializer.read_only
+        and getattr(serializer, 'partial', None)
+        and not getattr(serializer, 'read_only', None)
         and not (spectacular_settings.COMPONENT_SPLIT_REQUEST and direction == 'response')
     )
 
@@ -764,7 +764,11 @@ def _matches(cls, target) -> bool:
         if cls.target_class is None:
             return False  # app not installed
         elif cls.match_subclasses:
-            return issubclass(get_class(target), cls.target_class)  # type: ignore
+            # Targets may trigger customized check through __subclasscheck__. Attempt to be more robust
+            try:
+                return issubclass(get_class(target), cls.target_class)  # type: ignore
+            except TypeError:
+                return False
         else:
             return get_class(target) == cls.target_class