First stab at supporting the PATCH method.

rest_framework/compat.py

@@ -59,6 +59,10 @@ else:
             update_wrapper(view, cls.dispatch, assigned=())
             return view
 
+http_method_names = set(View.http_method_names)
+http_method_names.add('patch')
+View.http_method_names = list(http_method_names)  # PATCH method is not implemented by Django
+
 # PUT, DELETE do not require CSRF until 1.4.  They should.  Make it better.
 if django.VERSION >= (1, 4):
     from django.middleware.csrf import CsrfViewMiddleware

rest_framework/generics.py

@@ -138,11 +138,14 @@ class UpdateAPIView(mixins.UpdateModelMixin,
                     SingleObjectAPIView):
 
     """
-    Concrete view for updating a model instance.
+    Concrete view for updating or partially updating a model instance.
     """
     def put(self, request, *args, **kwargs):
         return self.update(request, *args, **kwargs)
 
+    def patch(self, request, *args, **kwargs):
+        return self.partially_update(request, *args, **kwargs)
+
 
 class ListCreateAPIView(mixins.ListModelMixin,
                         mixins.CreateModelMixin,
@@ -175,7 +178,7 @@ class RetrieveUpdateDestroyAPIView(mixins.RetrieveModelMixin,
                                    mixins.DestroyModelMixin,
                                    SingleObjectAPIView):
     """
-    Concrete view for retrieving, updating or deleting a model instance.
+    Concrete view for retrieving, updating, partially updating, or deleting a model instance.
     """
     def get(self, request, *args, **kwargs):
         return self.retrieve(request, *args, **kwargs)
@@ -183,5 +186,8 @@ class RetrieveUpdateDestroyAPIView(mixins.RetrieveModelMixin,
     def put(self, request, *args, **kwargs):
         return self.update(request, *args, **kwargs)
 
+    def patch(self, request, *args, **kwargs):
+        return self.partially_update(request, *args, **kwargs)
+
     def delete(self, request, *args, **kwargs):
         return self.destroy(request, *args, **kwargs)

rest_framework/mixins.py

@@ -82,7 +82,21 @@ class UpdateModelMixin(object):
             self.object = None
 
         serializer = self.get_serializer(data=request.DATA, instance=self.object)
+        if serializer.is_valid():
+            self.pre_save(serializer.object)
+            self.object = serializer.save()
+            return Response(serializer.data)
 
+        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
+
+    def partially_update(self, request, *args, **kwargs):
+        """
+        Updates model instance with only the fields present in request.DATA.
+        """
+        self.object = self.get_object()
+        data = self.get_serializer(instance=self.object).data
+        data.update(request.DATA)  # overwrite data with data from the request
+        serializer = self.get_serializer(data=data, instance=self.object)
         if serializer.is_valid():
             self.pre_save(serializer.object)
             self.object = serializer.save()