serializer update support

Author: pizzapanther

docs/rest-framework.rst

@@ -19,3 +19,50 @@ You can create a Mutation based on a serializer by using the
         class Meta:
             serializer_class = MySerializer
 
+Create/Update Operations
+---------------------
+
+By default ModelSerializers accept create and update operations. To
+customize this use the `model_operations` attribute. The update
+operation looks up models by the primary key by default. You can
+customize the look up with the lookup attribute.
+
+Other default attributes:
+
+`partial = False`: Accept updates without all the input fields.
+
+.. code:: python
+
+    from graphene_django.rest_framework.mutation import SerializerMutation
+
+    class AwesomeModelMutation(SerializerMutation):
+        class Meta:
+            serializer_class = MyModelSerializer
+            model_operations = ['create', 'update']
+            lookup_field = 'id'
+
+Overriding Update Queries
+-------------------------
+
+Use the method `get_serializer_kwargs` to override how
+updates are applied.
+
+.. code:: python
+
+    from graphene_django.rest_framework.mutation import SerializerMutation
+
+    class AwesomeModelMutation(SerializerMutation):
+        class Meta:
+            serializer_class = MyModelSerializer
+
+        @classmethod
+        def get_serializer_kwargs(cls, root, info, **input):
+            if 'id' in input:
+                instance = Post.objects.filter(id=input['id'], owner=info.context.user).first()
+                if instance:
+                    return {'instance': instance, 'data': input, 'partial': True}
+
+                else:
+                    raise http.Http404
+
+            return {'data': input, 'partial': True}

graphene_django/rest_framework/mutation.py

@@ -1,5 +1,7 @@
 from collections import OrderedDict
 
+from django.shortcuts import get_object_or_404
+
 import graphene
 from graphene.types import Field, InputField
 from graphene.types.mutation import MutationOptions
@@ -15,6 +17,9 @@
 
 
 class SerializerMutationOptions(MutationOptions):
+    lookup_field = None
+    model_class = None
+    model_operations = ['create', 'update']
     serializer_class = None
 
 
@@ -44,18 +49,34 @@ class Meta:
     )
 
     @classmethod
-    def __init_subclass_with_meta__(cls, serializer_class=None,
+    def __init_subclass_with_meta__(cls, lookup_field=None,
+                                    serializer_class=None, model_class=None,
+                                    model_operations=['create', 'update'],
                                     only_fields=(), exclude_fields=(), **options):
 
         if not serializer_class:
             raise Exception('serializer_class is required for the SerializerMutation')
 
+        if 'update' not in model_operations and 'create' not in model_operations:
+            raise Exception('model_operations must contain "create" and/or "update"')
+
         serializer = serializer_class()
+        if model_class is None:
+            serializer_meta = getattr(serializer_class, 'Meta', None)
+            if serializer_meta:
+                model_class = getattr(serializer_meta, 'model', None)
+
+        if lookup_field is None and model_class:
+            lookup_field = model_class._meta.pk.name
+
         input_fields = fields_for_serializer(serializer, only_fields, exclude_fields, is_input=True)
         output_fields = fields_for_serializer(serializer, only_fields, exclude_fields, is_input=False)
 
         _meta = SerializerMutationOptions(cls)
+        _meta.lookup_field = lookup_field
+        _meta.model_operations = model_operations
         _meta.serializer_class = serializer_class
+        _meta.model_class = model_class
         _meta.fields = yank_fields_from_attrs(
             output_fields,
             _as=Field,
@@ -67,9 +88,35 @@ def __init_subclass_with_meta__(cls, serializer_class=None,
         )
         super(SerializerMutation, cls).__init_subclass_with_meta__(_meta=_meta, input_fields=input_fields, **options)
 
+    @classmethod
+    def get_serializer_kwargs(cls, root, info, **input):
+        lookup_field = cls._meta.lookup_field
+        model_class = cls._meta.model_class
+
+        if model_class:
+            if 'update' in cls._meta.model_operations and lookup_field in input:
+                instance = get_object_or_404(model_class, **{
+                    lookup_field: input[lookup_field]})
+            elif 'create' in cls._meta.model_operations:
+                instance = None
+            else:
+                raise Exception(
+                    'Invalid update operation. Input parameter "{}" required.'.format(
+                        lookup_field
+                    ))
+
+            return {
+                'instance': instance,
+                'data': input,
+                'context': {'request': info.context}
+            }
+
+        return {'data': input, 'context': {'request': info.context}}
+
     @classmethod
     def mutate_and_get_payload(cls, root, info, **input):
-        serializer = cls._meta.serializer_class(data=input)
+        kwargs = cls.get_serializer_kwargs(root, info, **input)
+        serializer = cls._meta.serializer_class(**kwargs)
 
         if serializer.is_valid():
             return cls.perform_mutate(serializer, info)

graphene_django/rest_framework/tests/test_mutation.py

@@ -1,6 +1,6 @@
 import datetime
 
-from graphene import Field
+from graphene import Field, ResolveInfo
 from graphene.types.inputobjecttype import InputObjectType
 from py.test import raises
 from py.test import mark
@@ -10,12 +10,29 @@
 from ..models import MyFakeModel
 from ..mutation import SerializerMutation
 
+def mock_info():
+  return ResolveInfo(
+    None,
+    None,
+    None,
+    None,
+    schema=None,
+    fragments=None,
+    root_value=None,
+    operation=None,
+    variable_values=None,
+    context=None
+  )
+
 
 class MyModelSerializer(serializers.ModelSerializer):
     class Meta:
         model = MyFakeModel
         fields = '__all__'
 
+class MyModelMutation(SerializerMutation):
+    class Meta:
+        serializer_class = MyModelSerializer
 
 class MySerializer(serializers.Serializer):
     text = serializers.CharField()
@@ -92,7 +109,7 @@ class MyMutation(SerializerMutation):
         class Meta:
             serializer_class = MySerializer
 
-    result = MyMutation.mutate_and_get_payload(None, None, **{
+    result = MyMutation.mutate_and_get_payload(None, mock_info(), **{
         'text': 'value',
         'model': {
             'cool_name': 'other_value'
@@ -102,34 +119,58 @@ class Meta:
 
 
 @mark.django_db
-def test_model_mutate_and_get_payload_success():
-    class MyMutation(SerializerMutation):
-        class Meta:
-            serializer_class = MyModelSerializer
-
-    result = MyMutation.mutate_and_get_payload(None, None, **{
+def test_model_add_mutate_and_get_payload_success():
+    result = MyModelMutation.mutate_and_get_payload(None, mock_info(), **{
         'cool_name': 'Narf',
     })
     assert result.errors is None
     assert result.cool_name == 'Narf'
     assert isinstance(result.created, datetime.datetime)
 
+@mark.django_db
+def test_model_update_mutate_and_get_payload_success():
+    instance = MyFakeModel.objects.create(cool_name="Narf")
+    result = MyModelMutation.mutate_and_get_payload(None, mock_info(), **{
+        'id': instance.id,
+        'cool_name': 'New Narf',
+    })
+    assert result.errors is None
+    assert result.cool_name == 'New Narf'
+
+@mark.django_db
+def test_model_invalid_update_mutate_and_get_payload_success():
+    class InvalidModelMutation(SerializerMutation):
+        class Meta:
+            serializer_class = MyModelSerializer
+            model_operations = ['update']
+
+    with raises(Exception) as exc:
+        result = InvalidModelMutation.mutate_and_get_payload(None, mock_info(), **{
+            'cool_name': 'Narf',
+        })
+
+    assert '"id" required' in str(exc.value)
+
 def test_mutate_and_get_payload_error():
 
     class MyMutation(SerializerMutation):
         class Meta:
             serializer_class = MySerializer
 
     # missing required fields
-    result = MyMutation.mutate_and_get_payload(None, None, **{})
+    result = MyMutation.mutate_and_get_payload(None, mock_info(), **{})
     assert len(result.errors) > 0
 
 def test_model_mutate_and_get_payload_error():
-
-    class MyMutation(SerializerMutation):
-        class Meta:
-            serializer_class = MyModelSerializer
-
     # missing required fields
-    result = MyMutation.mutate_and_get_payload(None, None, **{})
+    result = MyModelMutation.mutate_and_get_payload(None, mock_info(), **{})
     assert len(result.errors) > 0
+
+def test_invalid_serializer_operations():
+    with raises(Exception) as exc:
+        class MyModelMutation(SerializerMutation):
+            class Meta:
+                serializer_class = MyModelSerializer
+                model_operations = ['Add']
+
+    assert 'model_operations' in str(exc.value)