One-to-many writable, nested serializer support

rest_framework/serializers.py

@@ -299,6 +299,19 @@ class BaseSerializer(WritableField):
             ret.fields[key] = field
         return ret
 
+    def _get_object_from_data(self, objects, data):
+        """
+        Get the corresponding object to deserialize the data into.
+        """
+        # Just get the first object in the list.
+        if objects:
+            obj = objects[0]
+            objects.remove(obj)
+        else:
+            obj = None
+
+        return obj
+
     def from_native(self, data, files):
         """
         Deserialize primitives -> objects.
@@ -365,6 +378,9 @@ class BaseSerializer(WritableField):
         # Set the serializer object if it exists
         obj = getattr(self.parent.object, field_name) if self.parent.object else None
 
+        if is_simple_callable(getattr(obj, 'all', None)):
+            obj = list(obj.all())
+
         if value in (None, ''):
             into[(self.source or field_name)] = None
         else:
@@ -404,9 +420,17 @@ class BaseSerializer(WritableField):
             if many:
                 ret = []
                 errors = []
+                objects = self.object
                 for item in data:
+                    obj = self._get_object_from_data(objects, item)
+                    self.object = obj
                     ret.append(self.from_native(item, None))
                     errors.append(self._errors)
+                self.object = objects
+                # Unused objects will be deleted
+                for obj in objects or []:
+                    obj._delete = True
+                    ret.append(obj)
                 self._errors = any(errors) and errors or []
             else:
                 ret = self.from_native(data, files)
@@ -498,6 +522,27 @@ class ModelSerializer(Serializer):
         models.ImageField: ImageField,
     }
 
+    def _get_object_from_data(self, objects, data):
+        """
+        Get the corresponding object to deserialize the data into.
+        """
+        if objects is None: return None
+
+        # Get the object based on pk
+        pk_field_name = self.opts.model._meta.pk.name
+        pk = data.get(pk_field_name, None)
+        if pk:
+            # Loop through objects and find one with pk or return None
+            obj = [o for o in objects if o.pk == pk]
+            if obj:
+                obj = obj[0]
+                objects.remove(obj)
+            else:
+                obj = None
+            return obj
+        else:
+            return None
+
     def get_default_fields(self):
         """
         Return all the fields that should be serialized for the model.
@@ -704,6 +749,14 @@ class ModelSerializer(Serializer):
                     fk_field = obj._meta.get_field_by_name(accessor_name)[0].field.name
                     setattr(related, fk_field, obj)
                     self.save_object(related)
+                elif hasattr(related, '__iter__'):
+                    for related_obj in related:
+                        if getattr(related_obj, '_delete', None):
+                            related_obj.delete()
+                            continue
+                        fk_field = obj._meta.get_field_by_name(accessor_name)[0].field.name
+                        setattr(related_obj, fk_field, obj)
+                        self.save_object(related_obj)                        
                 else:
                     setattr(obj, accessor_name, related)
             del(obj._related_data)

rest_framework/tests/relations_nested.py

@@ -40,6 +40,49 @@ class OneToOneTargetSerializer(serializers.ModelSerializer):
         model = OneToOneTarget
 
 
+class OneToManyTarget(models.Model):
+    name = models.CharField(max_length=100)
+
+
+class OneToManyTargetSource(models.Model):
+    name = models.CharField(max_length=100)
+    target = models.ForeignKey(OneToManyTarget,
+                               related_name='target_sources')
+
+
+class OneToManySource(models.Model):
+    name = models.CharField(max_length=100)
+    target_source = models.ForeignKey(OneToManyTargetSource,
+                                      related_name='sources')
+
+
+class OneToManySource(models.Model):
+    name = models.CharField(max_length=100)
+    target = models.ForeignKey(OneToManyTarget,
+                               related_name='sources')
+
+
+class OneToManySourceSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = OneToManySource
+        exclude = ('target_source', )
+
+
+class OneToManyTargetSourceSerializer(serializers.ModelSerializer):
+    sources = OneToManySourceSerializer(many=True)
+
+    class Meta:
+        model = OneToManyTargetSource
+        exclude = ('target', )
+
+
+class OneToManyTargetSerializer(serializers.ModelSerializer):
+    target_sources = OneToManyTargetSourceSerializer(many=True)
+
+    class Meta:
+        model = OneToManyTarget
+
+
 class NestedOneToOneTests(TestCase):
     def setUp(self):
         for idx in range(1, 4):
@@ -123,3 +166,77 @@ class NestedOneToOneTests(TestCase):
             {'id': 3, 'name': 'target-3', 'target_source': None}
         ]
         self.assertEqual(serializer.data, expected)
+
+
+class NestedOneToManyTests(TestCase):
+    def setUp(self):
+        target = OneToManyTarget(name='target-1')
+        target.save()
+        target_source = OneToManyTargetSource(name='target-source-1', target=target)
+        target_source.save()
+        for idx in range(1, 4):
+            source = OneToManySource(name='source-%d' % idx, target_source=target_source)
+            source.save()
+
+    def test_one_to_many_retrieve(self):
+        queryset = OneToManyTarget.objects.all()
+        serializer = OneToManyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': 'target-1', 'target_sources': [{'id': 1, 'name': 'target-source-1', 'sources': [{'id': 1, 'name': 'source-1'}, {'id': 2, 'name': 'source-2'}, {'id': 3, 'name': 'source-3'}]}]}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_one_to_many_create(self):
+        # Note the nonsensical source id given
+        data = {'id': 2, 'name': 'target-2', 'target_sources': [{'id': 2, 'name': 'target-source-2', 'sources': [{'id': 2, 'name': 'source-4'}]}]}
+        expected = {'id': 2, 'name': 'target-2', 'target_sources': [{'id': 2, 'name': 'target-source-2', 'sources': [{'id': 4, 'name': 'source-4'}]}]}
+        serializer = OneToManyTargetSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, expected)
+        self.assertEqual(obj.name, 'target-2')
+
+        # Ensure (target 4, target_source 4, source 4) are added, and
+        # everything else is as expected.
+        queryset = OneToManyTarget.objects.all()
+        serializer = OneToManyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': 'target-1', 'target_sources': [{'id': 1, 'name': 'target-source-1', 'sources': [{'id': 1, 'name': 'source-1'}, {'id': 2, 'name': 'source-2'}, {'id': 3, 'name': 'source-3'}]}]},
+            {'id': 2, 'name': 'target-2', 'target_sources': [{'id': 2, 'name': 'target-source-2', 'sources': [{'id': 4, 'name': 'source-4'}]}]}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_one_to_many_update(self):
+        data = {'id': 1, 'name': 'target-1-updated', 'target_sources': [{'id': 1, 'name': 'target-source-1-updated', 'sources': [{'id': 1, 'name': 'source-1-updated'}, {'id': 2, 'name': 'source-2'}, {'id': 3, 'name': 'source-3'}]}]}
+        expected = {'id': 1, 'name': 'target-1-updated', 'target_sources': [{'id': 1, 'name': 'target-source-1-updated', 'sources': [{'id': 1, 'name': 'source-1-updated'}, {'id': 2, 'name': 'source-2'}, {'id': 3, 'name': 'source-3'}]}]}
+        instance = OneToManyTarget.objects.get(pk=1)
+        serializer = OneToManyTargetSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, expected)
+        self.assertEqual(obj.name, 'target-1-updated')
+
+        # Ensure (target 1, target_source 1, source 1) are updated,
+        # and everything else is as expected.
+        queryset = OneToManyTarget.objects.all()
+        serializer = OneToManyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': 'target-1-updated', 'target_sources': [{'id': 1, 'name': 'target-source-1-updated', 'sources': [{'id': 1, 'name': 'source-1-updated'}, {'id': 2, 'name': 'source-2'}, {'id': 3, 'name': 'source-3'}]}]}
+            ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_one_to_many_delete(self):
+        data = {'id': 1, 'name': 'target-1', 'target_sources': [{'id': 1, 'name': 'target-source-1', 'sources': [{'id': 2, 'name': 'source-2'}]}]}
+        instance = OneToManyTarget.objects.get(pk=1)
+        serializer = OneToManyTargetSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+
+        # Ensure target_source 1 is deleted, and everything else is as
+        # expected.
+        queryset = OneToManyTarget.objects.all()
+        serializer = OneToManyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': 'target-1', 'target_sources': [{'id': 1, 'name': 'target-source-1', 'sources': [{'id': 2, 'name': 'source-2'}]}]}
+            ]
+        self.assertEquals(serializer.data, expected)

rest_framework/tests/serializer.py

@@ -266,7 +266,7 @@ class ValidationTests(TestCase):
         Data of the wrong type is not valid.
         """
         data = ['i am', 'a', 'list']
-        serializer = CommentSerializer(self.comment, data=data, many=True)
+        serializer = CommentSerializer([self.comment], data=data, many=True)
         self.assertEqual(serializer.is_valid(), False)
         self.assertTrue(isinstance(serializer.errors, list))