Make modelserializer support writable properties on models it instantiates.

rest_framework/serializers.py

@@ -858,14 +858,18 @@ class ModelSerializer(Serializer):
             if isinstance(self.fields.get(field_name, None), Serializer):
                 nested_forward_relations[field_name] = attrs[field_name]
 
-        # Update an existing instance...
+        if instance is None:
-        if instance is not None:
+            # Create a new instance, if we need to
-            for key, val in attrs.items():
+            field_attrs = {}
-                setattr(instance, key, val)
+            for field_name in meta.get_all_field_names():
+                if field_name in attrs:
+                    field_attrs[field_name] = attrs.pop(field_name)
 
-        # ...or create a new instance
+            instance = self.opts.model(**field_attrs)
-        else:
+
-            instance = self.opts.model(**attrs)
+        # Update an existing instance...
+        for key, val in attrs.items():
+            setattr(instance, key, val)
 
         # Any relations that cannot be set until we've
         # saved the model get hidden away on these

rest_framework/tests/models.py

@@ -81,10 +81,16 @@ class Person(RESTFrameworkModel):
 
     @property
     def info(self):
-        return {
+        if not hasattr(self, '_info'):
-            'name': self.name,
+            self._info = {
-            'age': self.age,
+                'name': self.name,
-        }
+                'age': self.age,
+            }
+        return self._info
+
+    @info.setter
+    def info(self, value):
+        self._info = value
 
 
 class BlogPost(RESTFrameworkModel):
@@ -163,6 +169,18 @@ class NullableOneToOneSource(RESTFrameworkModel):
                                   related_name='nullable_source')
 
 
+class ModelWithWritableProperty(RESTFrameworkModel):
+    name = models.CharField(max_length=100)
+
+    @property
+    def prop(self):
+        return getattr(self, '_value', 'hi!')
+
+    @prop.setter
+    def prop(self, value):
+        self._value = value
+
+
 # Serializer used to test BasicModel
 class BasicModelSerializer(serializers.ModelSerializer):
     class Meta:

rest_framework/tests/test_serializer.py

@@ -7,7 +7,7 @@ from django.utils.translation import ugettext_lazy as _
 from rest_framework import serializers, fields, relations
 from rest_framework.tests.models import (HasPositiveIntegerAsChoice, Album, ActionItem, Anchor, BasicModel,
     BlankFieldModel, BlogPost, BlogPostComment, Book, CallableDefaultValueModel, DefaultValueModel,
-    ManyToManyModel, Person, ReadOnlyManyToManyModel, Photo, RESTFrameworkModel)
+    ManyToManyModel, Person, ReadOnlyManyToManyModel, Photo, RESTFrameworkModel, ModelWithWritableProperty)
 from rest_framework.tests.models import BasicModelSerializer
 import datetime
 import pickle
@@ -1643,3 +1643,24 @@ class SerializerSupportsManyRelationships(TestCase):
         serializer = SimpleSlugSourceModelSerializer(data={'text': 'foo', 'targets': [1, 2]})
         self.assertTrue(serializer.is_valid())
         self.assertEqual(serializer.data, {'text': 'foo', 'targets': [1, 2]})
+
+
+class WritablePropertyModelSerializer(serializers.ModelSerializer):
+    prop = serializers.CharField(source='prop')
+    class Meta:
+        model = ModelWithWritableProperty
+        fields = ('name', 'prop',)
+
+
+class ModelSerializerSupportsWritableProperty(TestCase):
+    def setUp(self):
+        ModelWithWritableProperty.objects.create(name='hey! ')
+
+    def test_modelserializer_create_with_property(self):
+        s = WritablePropertyModelSerializer(data={
+            'name': 'the name',
+            'prop': 'new value',
+        })
+        self.assertTrue(s.is_valid())
+        obj = s.save()
+        self.assertEqual(obj.prop, 'new value')