Merge pull request #1199 from yamila-moreno/get-filter-backends

Added get_filter_backends method

docs/api-guide/generic-views.md

@@ -121,6 +121,22 @@ For example:
 
 Note that if your API doesn't include any object level permissions, you may optionally exclude the ``self.check_object_permissions, and simply return the object from the `get_object_or_404` lookup.
 
+#### `get_filter_backends(self)`
+
+Returns the classes that should be used to filter the queryset. Defaults to returning the `filter_backends` attribute.
+
+May be override to provide more complex behavior with filters, as using different (or even exlusive) lists of filter_backends depending on different criteria.
+
+For example:
+
+    def get_filter_backends(self):
+        if "geo_route" in self.request.QUERY_PARAMS:
+            return (GeoRouteFilter, CategoryFilter)
+        elif "geo_point" in self.request.QUERY_PARAMS:
+            return (GeoPointFilter, CategoryFilter)
+
+        return (CategoryFilter,)
+
 #### `get_serializer_class(self)`
 
 Returns the class that should be used for the serializer.  Defaults to returning the `serializer_class` attribute, or dynamically generating a serializer class if the `model` shortcut is being used.
@@ -328,7 +344,7 @@ You can then simply apply this mixin to a view or viewset anytime you need to ap
         serializer_class = UserSerializer
         lookup_fields = ('account', 'username')
 
-Using custom mixins is a good option if you have custom behavior that needs to be used 
+Using custom mixins is a good option if you have custom behavior that needs to be used
 
 ## Creating custom base classes
 
@@ -337,7 +353,7 @@ If you are using a mixin across multiple views, you can take this a step further
     class BaseRetrieveView(MultipleFieldLookupMixin,
                            generics.RetrieveAPIView):
         pass
-    
+
     class BaseRetrieveUpdateDestroyView(MultipleFieldLookupMixin,
                                         generics.RetrieveUpdateDestroyAPIView):
         pass

rest_framework/generics.py

@@ -175,6 +175,14 @@ class GenericAPIView(views.APIView):
         method if you want to apply the configured filtering backend to the
         default queryset.
         """
+        for backend in self.get_filter_backends():
+            queryset = backend().filter_queryset(self.request, queryset, self)
+        return queryset
+
+    def get_filter_backends(self):
+        """
+        Returns the list of filter backends that this view requires.
+        """
         filter_backends = self.filter_backends or []
         if not filter_backends and self.filter_backend:
             warnings.warn(
@@ -185,10 +193,8 @@ class GenericAPIView(views.APIView):
                 PendingDeprecationWarning, stacklevel=2
             )
             filter_backends = [self.filter_backend]
+        return filter_backends
 
-        for backend in filter_backends:
-            queryset = backend().filter_queryset(self.request, queryset, self)
-        return queryset
 
     ########################
     ### The following methods provide default implementations