From a66f6f299076215a8b712502707669ed2eade25a Mon Sep 17 00:00:00 2001
From: Syrus Akbary <me@syrusakbary.com>
Date: Tue, 2 Feb 2016 19:00:36 -0800
Subject: [PATCH] Added source argument to Fields. Fixed #101

---
 graphene/core/classtypes/objecttype.py  |  3 ++
 graphene/core/types/field.py            | 14 +++++++--
 graphene/core/types/tests/test_field.py | 38 +++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/graphene/core/classtypes/objecttype.py b/graphene/core/classtypes/objecttype.py
index 442d78f5..d542f28c 100644
--- a/graphene/core/classtypes/objecttype.py
+++ b/graphene/core/classtypes/objecttype.py
@@ -46,6 +46,9 @@ class ObjectType(six.with_metaclass(ObjectTypeMeta, FieldsClassType)):
     class Meta:
         abstract = True
 
+    def __getattr__(self, name):
+        return self._root and getattr(self._root, name)
+
     def __init__(self, *args, **kwargs):
         signals.pre_init.send(self.__class__, args=args, kwargs=kwargs)
         self._root = kwargs.pop('_root', None)
diff --git a/graphene/core/types/field.py b/graphene/core/types/field.py
index 3db7ed68..3109ffe0 100644
--- a/graphene/core/types/field.py
+++ b/graphene/core/types/field.py
@@ -4,6 +4,7 @@ from functools import wraps
 import six
 from graphql.core.type import GraphQLField, GraphQLInputObjectField
 
+from ...utils import maybe_func
 from ..classtypes.base import FieldsClassType
 from ..classtypes.inputobjecttype import InputObjectType
 from ..classtypes.mutation import Mutation
@@ -18,7 +19,8 @@ class Field(NamedType, OrderedType):
 
     def __init__(
             self, type, description=None, args=None, name=None, resolver=None,
-            required=False, default=None, deprecation_reason=None, *args_list, **kwargs):
+            source=None, required=False, default=None, deprecation_reason=None,
+            *args_list, **kwargs):
         _creation_counter = kwargs.pop('_creation_counter', None)
         if isinstance(name, (Argument, ArgumentType)):
             kwargs['name'] = name
@@ -33,7 +35,12 @@ class Field(NamedType, OrderedType):
         args = OrderedDict(args or {}, **kwargs)
         self.arguments = ArgumentsGroup(*args_list, **args)
         self.object_type = None
+        self.attname = None
+        self.default_name = None
         self.resolver_fn = resolver
+        self.source = source
+        assert not (self.source and self.resolver_fn), ('You cannot have a source'
+                                                        ' and a resolver at the same time')
         self.default = default
 
     def contribute_to_class(self, cls, attname):
@@ -68,7 +75,8 @@ class Field(NamedType, OrderedType):
             return getattr(self.object_type, resolve_fn_name)
 
         def default_getter(instance, args, info):
-            return getattr(instance, self.attname, self.default)
+            value = getattr(instance, self.source or self.attname, self.default)
+            return maybe_func(value)
         return default_getter
 
     def get_type(self, schema):
@@ -80,6 +88,8 @@ class Field(NamedType, OrderedType):
         return snake_case_args(resolver)
 
     def internal_type(self, schema):
+        if not self.object_type:
+            raise Exception('The field is not mounted in any ClassType')
         resolver = self.resolver
         description = self.description
         arguments = self.arguments
diff --git a/graphene/core/types/tests/test_field.py b/graphene/core/types/tests/test_field.py
index 34690223..444e91b5 100644
--- a/graphene/core/types/tests/test_field.py
+++ b/graphene/core/types/tests/test_field.py
@@ -180,3 +180,41 @@ def test_field_internal_type_deprecated():
     type = schema.T(field)
     assert isinstance(type, GraphQLField)
     assert type.deprecation_reason == deprecation_reason
+
+
+def test_field_resolve_object():
+    class Root(object):
+        att = True
+
+        @staticmethod
+        def att_func():
+            return True
+
+    field = Field(String(), description='My argument')
+    field_func = Field(String(), description='My argument')
+
+    class Query(ObjectType):
+        att = field
+        att_func = field_func
+
+    assert field.resolver(Root, {}, None) is True
+    assert field.resolver(Root, {}, None) is True
+
+
+def test_field_resolve_source_object():
+    class Root(object):
+        att_source = True
+
+        @staticmethod
+        def att_func_source():
+            return True
+
+    field = Field(String(), source='att_source', description='My argument')
+    field_func = Field(String(), source='att_source', description='My argument')
+
+    class Query(ObjectType):
+        att = field
+        att_func = field_func
+
+    assert field.resolver(Root, {}, None) is True
+    assert field.resolver(Root, {}, None) is True