Fix #69

'cache' argument has already been removed, but the symptom was the same.
A non drf-filters FilterSet would not have the `get_subset` method and
error. This allows for compatibility.

Author: Ryan P Kilby

rest_framework_filters/backends.py

@@ -10,7 +10,8 @@ def filter_queryset(self, request, queryset, view):
         filter_class = self.get_filter_class(view, queryset)
 
         if filter_class:
-            subset_class = filter_class.get_subset(request.query_params)
-            return subset_class(request.query_params, queryset=queryset).qs
+            if hasattr(filter_class, 'get_subset'):
+                filter_class = filter_class.get_subset(request.query_params)
+            return filter_class(request.query_params, queryset=queryset).qs
 
         return queryset

tests/test_backends.py

@@ -1,10 +1,18 @@
 
-from django.test import TestCase, Client
+from rest_framework.test import APITestCase
 
+from .testapp import models
 
-class BackendTest(TestCase):
-    def setUp(self):
-        self.client = Client()
 
-    def test_get(self):
-        self.client.get('/notes')
+class BackendTest(APITestCase):
+
+    @classmethod
+    def setUpTestData(cls):
+        models.User.objects.create(username="user1", email="user1@example.org")
+        models.User.objects.create(username="user2", email="user2@example.org")
+
+    def test_django_filter_compatibility(self):
+        response = self.client.get('/df-users/', {'username': 'user1'}, content_type='json')
+
+        self.assertEqual(len(response.data), 1)
+        self.assertEqual(response.data[0]['username'], 'user1')

tests/testapp/filters.py

@@ -1,4 +1,5 @@
 
+import django_filters
 from rest_framework_filters import filters
 from rest_framework_filters.filters import RelatedFilter, AllLookupsFilter
 from rest_framework_filters.filterset import FilterSet, LOOKUP_SEP
@@ -9,6 +10,13 @@
 )
 
 
+class DFUserFilter(django_filters.FilterSet):
+    email = filters.CharFilter(name='email')
+
+    class Meta:
+        model = User
+
+
 class NoteFilterWithAll(FilterSet):
     title = AllLookupsFilter(name='title')
 

tests/testapp/urls.py

@@ -7,6 +7,7 @@
 
 
 router = routers.DefaultRouter()
+router.register(r'df-users', views.DFUserViewSet, base_name='df-users')
 router.register(r'users', views.UserViewSet,)
 router.register(r'notes', views.NoteViewSet,)
 

tests/testapp/views.py

@@ -4,7 +4,16 @@
 
 from .models import User, Note
 from .serializers import UserSerializer, NoteSerializer
-from .filters import UserFilterWithAll, NoteFilterWithRelatedAll
+from .filters import DFUserFilter, UserFilterWithAll, NoteFilterWithRelatedAll
+
+
+class DFUserViewSet(viewsets.ModelViewSet):
+    # used to test compatibility with the drf-filters backend
+    # with standard django-filter FilterSets.
+    queryset = User.objects.all()
+    serializer_class = UserSerializer
+    filter_backends = (backends.DjangoFilterBackend, )
+    filter_class = DFUserFilter
 
 
 class UserViewSet(viewsets.ModelViewSet):