Implement document filter for filtering with/without annotation

filter_fields=('seq_annotations__isnull',) is desirable but it can't.
See more detail:
https://github.com/carltongibson/django-filter/issues/743

app/server/api.py

@@ -16,6 +16,7 @@ from rest_framework.views import APIView
 from rest_framework.parsers import MultiPartParser
 
 from .exceptions import FileParseException
+from .filters import DocumentFilter
 from .models import Project, Label, Document
 from .models import SequenceAnnotation
 from .permissions import IsAdminUserAndWriteOnly, IsProjectUser, IsMyEntity, IsOwnAnnotation
@@ -98,8 +99,8 @@ class DocumentList(generics.ListCreateAPIView):
     filter_backends = (DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter)
     search_fields = ('text', )
     ordering_fields = ('created_at', 'updated_at', 'doc_annotations__updated_at',
-                       'seq_annotations__updated_at')
-    filter_fields = ('doc_annotations__label__id', 'seq_annotations__label__id')
+                       'seq_annotations__updated_at', 'seq2seq_annotations__updated_at')
+    filter_class = DocumentFilter
     permission_classes = (IsAuthenticated, IsProjectUser, IsAdminUserAndWriteOnly)
 
     def get_queryset(self):

app/server/filters.py

@@ -0,0 +1,14 @@
+from django_filters.rest_framework import FilterSet, BooleanFilter
+from .models import Document
+
+
+class DocumentFilter(FilterSet):
+    seq_annotations__isnull = BooleanFilter(field_name='seq_annotations', lookup_expr='isnull')
+    doc_annotations__isnull = BooleanFilter(field_name='doc_annotations', lookup_expr='isnull')
+    seq2seq_annotations__isnull = BooleanFilter(field_name='seq2seq_annotations', lookup_expr='isnull')
+
+    class Meta:
+        model = Document
+        fields = ('project', 'text', 'metadata', 'created_at', 'updated_at',
+                  'doc_annotations__label__id', 'seq_annotations__label__id',
+                  'doc_annotations__isnull', 'seq_annotations__isnull', 'seq2seq_annotations__isnull')

app/server/tests/test_api.py

@@ -758,11 +758,12 @@ class TestFilter(APITestCase):
         cls.project_member_pass = 'project_member_pass'
         project_member = User.objects.create_user(username=cls.project_member_name,
                                                   password=cls.project_member_pass)
-        cls.main_project = mommy.make('server.TextClassificationProject', users=[project_member])
+        cls.main_project = mommy.make('server.SequenceLabelingProject', users=[project_member])
         cls.label1 = mommy.make('server.Label', project=cls.main_project)
         cls.label2 = mommy.make('server.Label', project=cls.main_project)
         doc1 = mommy.make('server.Document', project=cls.main_project)
         doc2 = mommy.make('server.Document', project=cls.main_project)
+        doc3 = mommy.make('server.Document', project=cls.main_project)
         mommy.make('server.SequenceAnnotation', document=doc1, user=project_member, label=cls.label1)
         mommy.make('server.SequenceAnnotation', document=doc2, user=project_member, label=cls.label2)
         cls.url = reverse(viewname='doc_list', args=[cls.main_project.id])
@@ -777,6 +778,26 @@ class TestFilter(APITestCase):
         for d1, d2 in zip(response.data['results'], docs):
             self.assertEqual(d1['id'], d2['id'])
 
+    def test_can_filter_doc_with_annotation(self):
+        params = {'seq_annotations__isnull': False}
+        self.client.login(username=self.project_member_name,
+                          password=self.project_member_pass)
+        response = self.client.get(self.url, format='json', data=params)
+        docs = Document.objects.filter(project=self.main_project, seq_annotations__isnull=False).values()
+        self.assertEqual(response.data['count'], docs.count())
+        for d1, d2 in zip(response.data['results'], docs):
+            self.assertEqual(d1['id'], d2['id'])
+
+    def test_can_filter_doc_without_anotation(self):
+        params = {'seq_annotations__isnull': True}
+        self.client.login(username=self.project_member_name,
+                          password=self.project_member_pass)
+        response = self.client.get(self.url, format='json', data=params)
+        docs = Document.objects.filter(project=self.main_project, seq_annotations__isnull=True).values()
+        self.assertEqual(response.data['count'], docs.count())
+        for d1, d2 in zip(response.data['results'], docs):
+            self.assertEqual(d1['id'], d2['id'])
+
 
 class TestUploader(APITestCase):