57 non null fields

django_graph_api/graphql/schema.py

@@ -24,6 +24,7 @@
     SCALAR,
     String,
     UNION,
+    NonNull,
 )
 from django_graph_api.graphql.utils import (
     format_error,
@@ -174,6 +175,10 @@ def get_type(self):
             type_ = field.object_type
             if isinstance(field.type_, List):
                 type_ = List(type_)
+            elif not field.null:
+                type_ = NonNull(type_)
+        elif not field.null:
+            type_ = NonNull(field.type_)
         else:
             type_ = field.type_
         return type_
@@ -204,7 +209,7 @@ class TypeObject(Object):
     ofType = RelatedField('self')
 
     def get_name(self):
-        if self.data.kind == LIST:
+        if self.data.kind in [LIST, NON_NULL]:
             return None
         return self.data.object_name
 
@@ -241,7 +246,7 @@ def get_enumValues(self):
         return self.data.values
 
     def get_ofType(self):
-        if self.data.kind == LIST:
+        if self.data.kind in [LIST, NON_NULL]:
             return self.data.type_
         return None
 
@@ -269,8 +274,6 @@ def _collect_types(self, object_type, types=None):
                 if enum_type in types:
                     continue
                 types.add(enum_type)
-            elif isinstance(field.type_, List):
-                field = field.type_
             elif field.type_:
                 types.add(field.type_)
         return types

django_graph_api/graphql/types.py

@@ -52,9 +52,10 @@ class Field(object):
     creation_counter = 0
     arguments = {}
 
-    def __init__(self, description=None, arguments=None):
+    def __init__(self, description=None, arguments=None, null=True):
         self.arguments = arguments or {}
         self.description = description
+        self.null = null
 
         # Increase the creation counter, and save our local copy.
         self.creation_counter = Field.creation_counter
@@ -66,11 +67,17 @@ def __init__(self, description=None, arguments=None):
 
     def get_value(self):
         raw_value = self.get_raw_value()
+        if not self.null and raw_value is None:
+            raise GraphQLError('Field {} returned null but is not nullable'.format(self.name))
         if hasattr(self.type_, 'coerce_result'):
             try:
                 return self.type_.coerce_result(raw_value)
             except ValueError:
-                return None
+                raise GraphQLError('Cannot coerce {} ({}) to {}'.format(
+                    type(raw_value).__name__,
+                    raw_value,
+                    self.type_.object_name
+                ))
         return raw_value
 
     def get_raw_value(self):
@@ -106,8 +113,12 @@ def get_resolver_args(self):
                     input_value = self.obj.variables.get(variable_name, default_value)
                 try:
                     arg_value = value.coerce_input(input_value)
-                except TypeError:
-                    error = 'Argument {} expected a {} but got a {}'.format(key, type(value), type(input_value))
+                except ValueError:
+                    error = 'Query error: Argument {} expected a {} but got a {}'.format(
+                        key,
+                        type(value),
+                        type(input_value)
+                    )
                     raise GraphQLError(error)
                 resolver_args[key] = arg_value
             else:
@@ -210,6 +221,13 @@ class Enum(Scalar):
     values = ()
 
 
+class NonNull(object):
+    kind = NON_NULL
+
+    def __init__(self, type_):
+        self.type_ = type_
+
+
 class List(object):
     kind = LIST
 

django_graph_api/tests/graphql/test_types.py

@@ -12,7 +12,10 @@
     Float,
     Int,
     List,
-    String)
+    String,
+    IntegerField,
+)
+from django_graph_api.graphql.utils import GraphQLError
 
 
 @patch('django_graph_api.graphql.types.Boolean.coerce_result')
@@ -43,6 +46,44 @@ def test_field_get_resolver_args_calls_coerce_input(coerce_input_mock):
     coerce_input_mock.assert_called_once_with('bar')
 
 
+def test_get_value_coercion_error():
+    field = IntegerField()
+    selection = mock.MagicMock()
+    selection.name = 'foo'
+    obj = mock.MagicMock()
+    obj.get_foo.return_value = 'bar'
+    field.bind(selection, obj)
+
+    with pytest.raises(GraphQLError):
+        field.get_value()
+
+
+def test_get_resolver_args_coercion_error():
+    field = CharField(arguments={'foo': Int()})
+    selection = mock.MagicMock()
+    argument = mock.Mock()
+    argument.name = 'foo'
+    argument.value = 'bar'
+    selection.arguments = [argument]
+    obj = mock.MagicMock()
+    field.bind(selection, obj)
+
+    with pytest.raises(GraphQLError):
+        field.get_resolver_args()
+
+
+def test_get_value_non_null():
+    field = IntegerField(null=False)
+    selection = mock.MagicMock()
+    selection.name = 'foo'
+    obj = mock.MagicMock()
+    obj.get_foo.return_value = None
+    field.bind(selection, obj)
+
+    with pytest.raises(GraphQLError):
+        field.get_value()
+
+
 def test_int_coerce_result():
     assert Int.coerce_result(True) is 1
     assert Int.coerce_result(4.9) is 4

django_graph_api/tests/test_introspection.py

@@ -18,6 +18,7 @@
     ManyRelatedField,
     RelatedField,
     String,
+    NonNull,
 )
 
 from test_app.schema import (
@@ -79,6 +80,36 @@ def test_type__scalar__get_ofType():
     assert type_object.get_ofType() is None
 
 
+def test_type__non_null__get_fields():
+    type_object = TypeObject(None, NonNull(Boolean), None)
+    assert type_object.get_fields() is None
+
+
+def test_type__non_null__get_inputFields():
+    type_object = TypeObject(None, NonNull(Boolean), None)
+    assert type_object.get_inputFields() is None
+
+
+def test_type__non_null__get_interfaces():
+    type_object = TypeObject(None, NonNull(Boolean), None)
+    assert type_object.get_interfaces() is None
+
+
+def test_type__non_null__get_possibleTypes():
+    type_object = TypeObject(None, NonNull(Boolean), None)
+    assert type_object.get_possibleTypes() is None
+
+
+def test_type__non_null__get_enumValues():
+    type_object = TypeObject(None, NonNull(Boolean), None)
+    assert type_object.get_enumValues() is None
+
+
+def test_type__non_null__get_ofType():
+    type_object = TypeObject(None, NonNull(Boolean), None)
+    assert type_object.get_ofType() is Boolean
+
+
 def test_type__object__get_name():
     type_object = TypeObject(None, Character, None)
     assert type_object.get_name() == 'Character'
@@ -301,6 +332,14 @@ def test_execute__filter_type():
             kind
             fields {
                 name
+                type {
+                    name
+                    kind
+                    ofType {
+                        name
+                        kind
+                    }
+                }
             }
         }
     }
@@ -311,11 +350,55 @@ def test_execute__filter_type():
                 'name': 'Character',
                 'kind': 'OBJECT',
                 'fields': [
-                    {'name': 'appears_in'},
-                    {'name': 'best_friend'},
-                    {'name': 'friends'},
-                    {'name': 'id'},
-                    {'name': 'name'},
+                    {
+                        'name': 'appears_in',
+                        'type': {
+                            'name': None,
+                            'kind': 'LIST',
+                            'ofType': {
+                                'name': 'Episode',
+                                'kind': 'OBJECT'
+                            }
+                        },
+                    },
+                    {
+                        'name': 'best_friend',
+                        'type': {
+                            'name': 'Character',
+                            'kind': 'OBJECT',
+                            'ofType': None
+                        },
+                    },
+                    {
+                        'name': 'friends',
+                        'type': {
+                            'name': None,
+                            'kind': 'LIST',
+                            'ofType': {
+                                'name': 'Character',
+                                'kind': 'OBJECT'
+                            }
+                        },
+                    },
+                    {
+                        'name': 'id',
+                        'type': {
+                            'name': None,
+                            'kind': 'NON_NULL',
+                            'ofType': {
+                                'name': 'Int',
+                                'kind': 'SCALAR'
+                            }
+                        },
+                    },
+                    {
+                        'name': 'name',
+                        'type': {
+                            'name': 'String',
+                            'kind': 'SCALAR',
+                            'ofType': None
+                        },
+                    },
                 ],
             }
         }

test_app/schema.py

@@ -46,7 +46,7 @@ def get_characters(self, types):
 
 
 class Character(Object):
-    id = IntegerField()
+    id = IntegerField(null=False)
     name = CharField()
     friends = ManyRelatedField('self')
     best_friend = RelatedField('self')
@@ -58,9 +58,9 @@ def get_best_friend(self):
 
 @schema.register_query_root
 class QueryRoot(Object):
-    hero = RelatedField(Character)
+    hero = RelatedField(Character, null=False)
     episodes = ManyRelatedField(Episode)
-    episode = RelatedField(Episode, arguments={'number': Int()})
+    episode = RelatedField(Episode, arguments={'number': Int()}, null=False)
 
     def get_hero(self):
         return CharacterModel.objects.get(name='R2-D2')