From 03c4d8fadb80c47c87d718da5d487dd187436934 Mon Sep 17 00:00:00 2001
From: Tommy Beadle <tbeadle@gmail.com>
Date: Mon, 27 Mar 2017 14:51:39 -0400
Subject: [PATCH] Make mixins available to implement only PUT or only PATCH.

This makes it so that a user can include PartialUpdateModelMixin or
FullUpdateModelMixin if he/she wants only the PATCH or PUT ability, but
not both.  The UpdateModelMixin class is maintained for the common
desire to have both.
---
 docs/api-guide/generic-views.md | 10 ++++++++
 rest_framework/mixins.py        | 30 +++++++++++++++++-----
 tests/test_routers.py           | 45 +++++++++++++++++++++++++++++----
 3 files changed, 74 insertions(+), 11 deletions(-)

diff --git a/docs/api-guide/generic-views.md b/docs/api-guide/generic-views.md
index ae2705080..1f1210325 100644
--- a/docs/api-guide/generic-views.md
+++ b/docs/api-guide/generic-views.md
@@ -222,6 +222,16 @@ If an object is updated this returns a `200 OK` response, with a serialized repr
 
 If the request data provided for updating the object was invalid, a `400 Bad Request` response will be returned, with the error details as the body of the response.
 
+## PartialUpdateModelMixin
+
+Similar to `UpdateModelMixin` except that it only includes the `partial_update`
+(i.e. `PATCH`) capability and not the `update` (i.e. `PUT`) capability.
+
+## FullUpdateModelMixin
+
+Similar to `UpdateModelMixin` except that it only includes the `update`
+(i.e. `PUT`) capability and not the `partial_update` (i.e. `PATCH`) capability.
+
 ## DestroyModelMixin
 
 Provides a `.destroy(request, *args, **kwargs)` method, that implements deletion of an existing model instance.
diff --git a/rest_framework/mixins.py b/rest_framework/mixins.py
index f3695e665..04364f322 100644
--- a/rest_framework/mixins.py
+++ b/rest_framework/mixins.py
@@ -58,11 +58,8 @@ class RetrieveModelMixin(object):
         return Response(serializer.data)
 
 
-class UpdateModelMixin(object):
-    """
-    Update a model instance.
-    """
-    def update(self, request, *args, **kwargs):
+class _UpdateModelMixin(object):
+    def do_update(self, request, *args, **kwargs):
         partial = kwargs.pop('partial', False)
         instance = self.get_object()
         serializer = self.get_serializer(instance, data=request.data, partial=partial)
@@ -79,9 +76,30 @@ class UpdateModelMixin(object):
     def perform_update(self, serializer):
         serializer.save()
 
+
+class PartialUpdateModelMixin(_UpdateModelMixin):
+    """
+    Partial update a model instance.
+    """
     def partial_update(self, request, *args, **kwargs):
         kwargs['partial'] = True
-        return self.update(request, *args, **kwargs)
+        return self.do_update(request, *args, **kwargs)
+
+
+class FullUpdateModelMixin(object):
+    """
+    Full update a model instance.
+    """
+    def update(self, request, *args, **kwargs):
+        kwargs['partial'] = False
+        return self.do_update(request, *args, **kwargs)
+
+
+class UpdateModelMixin(FullUpdateModelMixin, PartialUpdateModelMixin):
+    """
+    Update a model instance fully or partially.
+    """
+    pass
 
 
 class DestroyModelMixin(object):
diff --git a/tests/test_routers.py b/tests/test_routers.py
index dc3df2e7b..322cdb643 100644
--- a/tests/test_routers.py
+++ b/tests/test_routers.py
@@ -9,7 +9,7 @@ from django.core.exceptions import ImproperlyConfigured
 from django.db import models
 from django.test import TestCase, override_settings
 
-from rest_framework import permissions, serializers, viewsets
+from rest_framework import mixins, permissions, serializers, viewsets
 from rest_framework.compat import include
 from rest_framework.decorators import detail_route, list_route
 from rest_framework.response import Response
@@ -115,10 +115,6 @@ class BasicViewSet(viewsets.ViewSet):
         return Response({'method': 'link2'})
 
 
-class TestSimpleRouter(TestCase):
-    def setUp(self):
-        self.router = SimpleRouter()
-
     def test_link_and_action_decorator(self):
         routes = self.router.get_routes(BasicViewSet)
         decorator_routes = routes[2:]
@@ -138,6 +134,45 @@ class TestSimpleRouter(TestCase):
                 assert route.mapping[method] == endpoint
 
 
+class TestUpdateViewSets(TestCase):
+    """
+    Verify that the *UpdateModelMixin mixin classes expose the correct methods
+    for a router to pick up.
+    """
+    def test_update_viewsets(self):
+        class PartialUpdateViewSet(
+                mixins.PartialUpdateModelMixin,
+                viewsets.GenericViewSet,
+        ):
+            pass
+
+
+        class FullUpdateViewSet(
+                mixins.FullUpdateModelMixin,
+                viewsets.GenericViewSet,
+        ):
+            pass
+
+
+        class UpdateViewSet(
+                mixins.FullUpdateModelMixin,
+                viewsets.GenericViewSet,
+        ):
+            pass
+
+
+        for cls, actions in (
+            (PartialUpdateViewSet, {'patch', 'partial_update'}),
+            (FullUpdateViewSet, {'put', 'update'}),
+            (UpdateViewSet, {'patch': 'partial_update', 'put', 'update'}),
+        ):
+            router = SimpleRouter()
+            router.register('test', cls, 'basename')
+            urls = router.get_urls()
+            assert len(urls) == 1
+            assert urls[0].callback.actions == actions
+
+
 @override_settings(ROOT_URLCONF='tests.test_routers')
 class TestRootView(TestCase):
     def test_retrieve_namespaced_root(self):