Support nullable FKs, with blank=True

rest_framework/fields.py

@@ -350,7 +350,13 @@ class RelatedField(WritableField):
             return
 
         value = data.get(field_name)
-        into[(self.source or field_name)] = self.from_native(value)
+
+        if value is None and not self.blank:
+            raise ValidationError('Value may not be null')
+        elif value is None and self.blank:
+            into[(self.source or field_name)] = None
+        else:
+            into[(self.source or field_name)] = self.from_native(value)
 
 
 class ManyRelatedMixin(object):

rest_framework/serializers.py

@@ -431,10 +431,14 @@ class ModelSerializer(Serializer):
         """
         # TODO: filter queryset using:
         # .using(db).complex_filter(self.rel.limit_choices_to)
-        queryset = model_field.rel.to._default_manager
+        kwargs = {
+            'blank': model_field.blank,
+            'queryset': model_field.rel.to._default_manager
+        }
+
         if to_many:
-            return ManyPrimaryKeyRelatedField(queryset=queryset)
-        return PrimaryKeyRelatedField(queryset=queryset)
+            return ManyPrimaryKeyRelatedField(**kwargs)
+        return PrimaryKeyRelatedField(**kwargs)
 
     def get_field(self, model_field):
         """
@@ -572,9 +576,9 @@ class HyperlinkedModelSerializer(ModelSerializer):
         # TODO: filter queryset using:
         # .using(db).complex_filter(self.rel.limit_choices_to)
         rel = model_field.rel.to
-        queryset = rel._default_manager
         kwargs = {
-            'queryset': queryset,
+            'blank': model_field.blank,
+            'queryset': rel._default_manager,
             'view_name': self._get_default_view_name(rel)
         }
         if to_many:

rest_framework/tests/hyperlinkedserializers.py

 from django.conf.urls.defaults import patterns, url
 from django.test import TestCase
 from django.test.client import RequestFactory
+from django.utils import simplejson as json
 from rest_framework import generics, status, serializers
 from rest_framework.tests.models import Anchor, BasicModel, ManyToManyModel, BlogPost, BlogPostComment, Album, Photo, OptionalRelationModel
 
@@ -54,10 +55,12 @@ class BlogPostCommentListCreate(generics.ListCreateAPIView):
     model = BlogPostComment
     serializer_class = BlogPostCommentSerializer
 
+
 class BlogPostCommentDetail(generics.RetrieveAPIView):
     model = BlogPostComment
     serializer_class = BlogPostCommentSerializer
 
+
 class BlogPostDetail(generics.RetrieveAPIView):
     model = BlogPost
 
@@ -71,7 +74,7 @@ class AlbumDetail(generics.RetrieveAPIView):
     model = Album
 
 
-class OptionalRelationDetail(generics.RetrieveAPIView):
+class OptionalRelationDetail(generics.RetrieveUpdateDestroyAPIView):
     model = OptionalRelationModel
     model_serializer_class = serializers.HyperlinkedModelSerializer
 
@@ -162,7 +165,7 @@ class TestManyToManyHyperlinkedView(TestCase):
         GET requests to ListCreateAPIView should return list of objects.
         """
         request = factory.get('/manytomany/')
-        response = self.list_view(request).render()
+        response = self.list_view(request)
         self.assertEquals(response.status_code, status.HTTP_200_OK)
         self.assertEquals(response.data, self.data)
 
@@ -171,7 +174,7 @@ class TestManyToManyHyperlinkedView(TestCase):
         GET requests to ListCreateAPIView should return list of objects.
         """
         request = factory.get('/manytomany/1/')
-        response = self.detail_view(request, pk=1).render()
+        response = self.detail_view(request, pk=1)
         self.assertEquals(response.status_code, status.HTTP_200_OK)
         self.assertEquals(response.data, self.data[0])
 
@@ -194,7 +197,7 @@ class TestCreateWithForeignKeys(TestCase):
         }
 
         request = factory.post('/comments/', data=data)
-        response = self.create_view(request).render()
+        response = self.create_view(request)
         self.assertEqual(response.status_code, status.HTTP_201_CREATED)
         self.assertEqual(response['Location'], 'http://testserver/comments/1/')
         self.assertEqual(self.post.blogpostcomment_set.count(), 1)
@@ -219,7 +222,7 @@ class TestCreateWithForeignKeysAndCustomSlug(TestCase):
         }
 
         request = factory.post('/photos/', data=data)
-        response = self.list_create_view(request).render()
+        response = self.list_create_view(request)
         self.assertEqual(response.status_code, status.HTTP_201_CREATED)
         self.assertNotIn('Location', response, msg='Location should only be included if there is a "url" field on the serializer')
         self.assertEqual(self.post.photo_set.count(), 1)
@@ -244,6 +247,16 @@ class TestOptionalRelationHyperlinkedView(TestCase):
         for non existing relations.
         """
         request = factory.get('/optionalrelationmodel-detail/1')
-        response = self.detail_view(request, pk=1).render()
+        response = self.detail_view(request, pk=1)
         self.assertEquals(response.status_code, status.HTTP_200_OK)
         self.assertEquals(response.data, self.data)
+
+    def test_put_detail_view(self):
+        """
+        PUT requests to RetrieveUpdateDestroyAPIView with optional relations
+        should accept None for non existing relations.
+        """
+        response = self.client.put('/optionalrelation/1/',
+                                   data=json.dumps(self.data),
+                                   content_type='application/json')
+        self.assertEqual(response.status_code, status.HTTP_200_OK)

rest_framework/tests/pk_relations.py

@@ -49,9 +49,22 @@ class ForeignKeySourceSerializer(serializers.ModelSerializer):
         model = ForeignKeySource
 
 
+# Nullable ForeignKey
+
+class NullableForeignKeySource(models.Model):
+    name = models.CharField(max_length=100)
+    target = models.ForeignKey(ForeignKeyTarget, null=True, blank=True,
+                               related_name='nullable_sources')
+
+
+class NullableForeignKeySourceSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = NullableForeignKeySource
+
+
 # TODO: Add test that .data cannot be accessed prior to .is_valid
 
-class PrimaryKeyManyToManyTests(TestCase):
+class PKManyToManyTests(TestCase):
     def setUp(self):
         for idx in range(1, 4):
             target = ManyToManyTarget(name='target-%d' % idx)
@@ -137,7 +150,7 @@ class PrimaryKeyManyToManyTests(TestCase):
         self.assertEquals(serializer.data, expected)
 
 
-class PrimaryKeyForeignKeyTests(TestCase):
+class PKForeignKeyTests(TestCase):
     def setUp(self):
         target = ForeignKeyTarget(name='target-1')
         target.save()
@@ -174,7 +187,7 @@ class PrimaryKeyForeignKeyTests(TestCase):
         self.assertEquals(serializer.data, data)
         serializer.save()
 
-        # # Ensure source 1 is updated, and everything else is as expected
+        # Ensure source 1 is updated, and everything else is as expected
         queryset = ForeignKeySource.objects.all()
         serializer = ForeignKeySourceSerializer(queryset)
         expected = [
@@ -184,6 +197,40 @@ class PrimaryKeyForeignKeyTests(TestCase):
         ]
         self.assertEquals(serializer.data, expected)
 
+    def test_foreign_key_update_with_invalid_null(self):
+        data = {'id': 1, 'name': u'source-1', 'target': None}
+        instance = ForeignKeySource.objects.get(pk=1)
+        serializer = ForeignKeySourceSerializer(instance, data=data)
+        self.assertFalse(serializer.is_valid())
+        self.assertEquals(serializer.errors, {'target': [u'Value may not be null']})
+
+
+class PKNullableForeignKeyTests(TestCase):
+    def setUp(self):
+        target = ForeignKeyTarget(name='target-1')
+        target.save()
+        for idx in range(1, 4):
+            source = NullableForeignKeySource(name='source-%d' % idx, target=target)
+            source.save()
+
+    def test_foreign_key_update_with_valid_null(self):
+        data = {'id': 1, 'name': u'source-1', 'target': None}
+        instance = NullableForeignKeySource.objects.get(pk=1)
+        serializer = NullableForeignKeySourceSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        self.assertEquals(serializer.data, data)
+        serializer.save()
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': None},
+            {'id': 2, 'name': u'source-2', 'target': 1},
+            {'id': 3, 'name': u'source-3', 'target': 1}
+        ]
+        self.assertEquals(serializer.data, expected)
+
     # reverse foreign keys MUST be read_only
     # In the general case they do not provide .remove() or .clear()
     # and cannot be arbitrarily set.