Allow custom serializer class for request and response

docs/api-guide/viewsets.md

@@ -295,6 +295,8 @@ As with `ModelViewSet`, you'll normally need to provide at least the `queryset`
 
 Again, as with `ModelViewSet`, you can use any of the standard attributes and method overrides available to `GenericAPIView`.
 
+---
+
 # Custom ViewSet base classes
 
 You may need to provide custom `ViewSet` classes that do not have the full set of `ModelViewSet` actions, or that customize the behavior in some other way.
@@ -321,3 +323,44 @@ By creating your own base `ViewSet` classes, you can provide common behavior tha
 
 [cite]: https://guides.rubyonrails.org/action_controller_overview.html
 [routers]: routers.md
+
+---
+
+# Custom serializer for request and response
+
+It is possible to define at the view level (or for each custom method via the @action decorator) a custom serialization class for each request and response.
+To do this you need to define `request_serializer_response` and `response_serializer_response` and call them via `get_request_serializer` and `get_response_serializer`.
+
+
+        class UserViewSet(viewsets.ModelViewSet):
+        """
+        A viewset that provides the standard actions
+        """
+        queryset = User.objects.all()
+        serializer_class = UserSerializer
+
+        @action(
+            detail=True,
+            methods=['post'],
+            request_serializer_class=PasswordSerializer
+        )
+        def set_password(self, request, pk=None):
+            user = self.get_object()
+            serializer = self.get_request_serializer(data=request.data)
+            if serializer.is_valid():
+                user.set_password(serializer.validated_data['password'])
+                user.save()
+                return Response({'status': 'password set'})
+            else:
+                return Response(serializer.errors,
+                                status=status.HTTP_400_BAD_REQUEST)
+
+        @action(
+            detail=True,
+            methods=['get'],
+            request_response_class=ExtendedUserSerializer
+        )
+        def complete_profile(self, request, pk=None):
+            user = self.get_object()
+            response_serializer = self.get_response_serializer(user)
+            return Response(response_serializer.data)

rest_framework/generics.py

@@ -33,6 +33,8 @@ class GenericAPIView(views.APIView):
     # for all subsequent requests.
     queryset = None
     serializer_class = None
+    request_serializer_class = None
+    response_serializer_class = None
 
     # If you want to use object lookups other than pk, set 'lookup_field'.
     # For more complex lookup requirements override `get_object()`.
@@ -109,6 +111,23 @@ class GenericAPIView(views.APIView):
         kwargs.setdefault('context', self.get_serializer_context())
         return serializer_class(*args, **kwargs)
 
+    def get_request_serializer(self, *args, **kwargs):
+        """
+        Return the serializer instance that should be used for validating and
+        deserializing input.
+        """
+        serializer_class = self.get_request_serializer_class()
+        kwargs.setdefault('context', self.get_serializer_context())
+        return serializer_class(*args, **kwargs)
+
+    def get_response_serializer(self, *args, **kwargs):
+        """
+        Return the serializer instance that should be used for serializing output.
+        """
+        serializer_class = self.get_response_serializer_class()
+        kwargs.setdefault('context', self.get_serializer_context())
+        return serializer_class(*args, **kwargs)
+
     def get_serializer_class(self):
         """
         Return the class to use for the serializer.
@@ -127,6 +146,18 @@ class GenericAPIView(views.APIView):
 
         return self.serializer_class
 
+    def get_request_serializer_class(self):
+        """
+        Return the class to use as input serializer.
+        """
+        return self.request_serializer_class or self.get_serializer_class()
+
+    def get_response_serializer_class(self):
+        """
+        Returns the class to use as output serializer.
+        """
+        return self.response_serializer_class or self.get_serializer_class()
+
     def get_serializer_context(self):
         """
         Extra context provided to the serializer class.

rest_framework/schemas/openapi.py

@@ -627,15 +627,41 @@ class AutoSchema(ViewInspector):
         Override this method if your view uses a different serializer for
         handling request body.
         """
+        view = self.view
+
+        if not hasattr(view, "get_request_serializer"):
             return self.get_serializer(path, method)
 
+        try:
+            return view.get_request_serializer()
+        except exceptions.APIException:
+            warnings.warn(
+                "{}.get_request_serializer() raised an exception during "
+                "schema generation. Serializer fields will not be "
+                "generated for {} {}.".format(view.__class__.__name__, method, path)
+            )
+            return None
+
     def get_response_serializer(self, path, method):
         """
         Override this method if your view uses a different serializer for
         populating response data.
         """
+        view = self.view
+
+        if not hasattr(view, "get_response_serializer"):
             return self.get_serializer(path, method)
 
+        try:
+            return view.get_response_serializer()
+        except exceptions.APIException:
+            warnings.warn(
+                "{}.get_response_serializer() raised an exception during "
+                "schema generation. Serializer fields will not be "
+                "generated for {} {}.".format(view.__class__.__name__, method, path)
+            )
+            return None
+
     def _get_reference(self, serializer):
         return {'$ref': '#/components/schemas/{}'.format(self.get_component_name(serializer))}
 

tests/test_generics.py

@@ -692,3 +692,45 @@ class TestSerializer(TestCase):
         serializer = response.serializer
 
         assert serializer.context is context
+
+    def test_get_request_serializer_class(self):
+        class View(generics.GenericAPIView):
+            request_serializer_class = BasicSerializer
+
+        view = View()
+        assert view.get_request_serializer_class() == BasicSerializer
+
+    def test_get_response_serializer_class(self):
+        class TestResponseSerializerView(generics.GenericAPIView):
+            response_serializer_class = BasicSerializer
+
+        view = TestResponseSerializerView()
+        assert view.get_response_serializer_class() == BasicSerializer
+
+    def test_get_request_serializer(self):
+        class View(generics.ListAPIView):
+            request_serializer_class = BasicSerializer
+
+            def list(self, request):
+                response = Response()
+                response.serializer = self.get_request_serializer()
+                return response
+
+        view = View.as_view()
+        request = factory.get('/')
+        response = view(request)
+        assert isinstance(response.serializer, BasicSerializer)
+
+    def test_get_response_serializer(self):
+        class View(generics.ListAPIView):
+            response_serializer_class = BasicSerializer
+
+            def list(self, request):
+                response = Response()
+                response.serializer = self.get_response_serializer()
+                return response
+
+        view = View.as_view()
+        request = factory.get('/')
+        response = view(request)
+        assert isinstance(response.serializer, BasicSerializer)