Test and fix for #814.

rest_framework/filters.py

@@ -38,21 +38,27 @@ class DjangoFilterBackend(BaseFilterBackend):
         """
         filter_class = getattr(view, 'filter_class', None)
         filter_fields = getattr(view, 'filter_fields', None)
-        view_model = getattr(view, 'model', None)
+        model_cls = getattr(view, 'model', None)
+        queryset = getattr(view, 'queryset', None)
+        if model_cls is None and queryset is not None:
+            model_cls = queryset.model
 
         if filter_class:
             filter_model = filter_class.Meta.model
 
-            assert issubclass(filter_model, view_model), \
+            assert issubclass(filter_model, model_cls), \
                 'FilterSet model %s does not match view model %s' % \
-                (filter_model, view_model)
+                (filter_model, model_cls)
 
             return filter_class
 
         if filter_fields:
+            assert model_cls is not None, 'Cannot use DjangoFilterBackend ' \
+                'on a view which does not have a .model or .queryset attribute.'
+
             class AutoFilterSet(self.default_filter_set):
                 class Meta:
-                    model = view_model
+                    model = model_cls
                     fields = filter_fields
             return AutoFilterSet
 

rest_framework/tests/filterset.py

@@ -5,7 +5,7 @@ from django.core.urlresolvers import reverse
 from django.test import TestCase
 from django.test.client import RequestFactory
 from django.utils import unittest
-from rest_framework import generics, status, filters
+from rest_framework import generics, serializers, status, filters
 from rest_framework.compat import django_filters, patterns, url
 from rest_framework.tests.models import FilterableItem, BasicModel
 
@@ -52,6 +52,17 @@ if django_filters:
         filter_class = SeveralFieldsFilter
         filter_backend = filters.DjangoFilterBackend
 
+    # Regression test for #814
+    class FilterableItemSerializer(serializers.ModelSerializer):
+        class Meta:
+            model = FilterableItem
+
+    class FilterFieldsQuerysetView(generics.ListCreateAPIView):
+        queryset = FilterableItem.objects.all()
+        serializer_class = FilterableItemSerializer
+        filter_fields = ['decimal', 'date']
+        filter_backend = filters.DjangoFilterBackend
+
     urlpatterns = patterns('',
         url(r'^(?P<pk>\d+)/$', FilterClassDetailView.as_view(), name='detail-view'),
         url(r'^$', FilterClassRootView.as_view(), name='root-view'),
@@ -114,6 +125,21 @@ class IntegrationTestFiltering(CommonFilteringTestCase):
         expected_data = [f for f in self.data if f['date'] == search_date]
         self.assertEqual(response.data, expected_data)
 
+    @unittest.skipUnless(django_filters, 'django-filters not installed')
+    def test_filter_with_queryset(self):
+        """
+        Regression test for #814.
+        """
+        view = FilterFieldsQuerysetView.as_view()
+
+        # Tests that the decimal filter works.
+        search_decimal = Decimal('2.25')
+        request = factory.get('/?decimal=%s' % search_decimal)
+        response = view(request).render()
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        expected_data = [f for f in self.data if f['decimal'] == search_decimal]
+        self.assertEqual(response.data, expected_data)
+
     @unittest.skipUnless(django_filters, 'django-filters not installed')
     def test_get_filtered_class_root_view(self):
         """