Merge branch 'master' into union_connections

.travis.yml

@@ -6,19 +6,19 @@ python:
 - 3.5
 - pypy
 before_install:
-  - |
-      if [ "$TRAVIS_PYTHON_VERSION" = "pypy" ]; then
-        export PYENV_ROOT="$HOME/.pyenv"
-        if [ -f "$PYENV_ROOT/bin/pyenv" ]; then
-          cd "$PYENV_ROOT" && git pull
-        else
-          rm -rf "$PYENV_ROOT" && git clone --depth 1 https://github.com/yyuu/pyenv.git "$PYENV_ROOT"
-        fi
-        export PYPY_VERSION="4.0.1"
-        "$PYENV_ROOT/bin/pyenv" install "pypy-$PYPY_VERSION"
-        virtualenv --python="$PYENV_ROOT/versions/pypy-$PYPY_VERSION/bin/python" "$HOME/virtualenvs/pypy-$PYPY_VERSION"
-        source "$HOME/virtualenvs/pypy-$PYPY_VERSION/bin/activate"
-      fi
+- |
+  if [ "$TRAVIS_PYTHON_VERSION" = "pypy" ]; then
+    export PYENV_ROOT="$HOME/.pyenv"
+    if [ -f "$PYENV_ROOT/bin/pyenv" ]; then
+      cd "$PYENV_ROOT" && git pull
+    else
+      rm -rf "$PYENV_ROOT" && git clone --depth 1 https://github.com/yyuu/pyenv.git "$PYENV_ROOT"
+    fi
+    export PYPY_VERSION="4.0.1"
+    "$PYENV_ROOT/bin/pyenv" install "pypy-$PYPY_VERSION"
+    virtualenv --python="$PYENV_ROOT/versions/pypy-$PYPY_VERSION/bin/python" "$HOME/virtualenvs/pypy-$PYPY_VERSION"
+    source "$HOME/virtualenvs/pypy-$PYPY_VERSION/bin/activate"
+  fi
 install:
 - |
   if [ "$TEST_TYPE" = build ]; then
@@ -52,3 +52,10 @@ matrix:
   include:
   - python: '2.7'
     env: TEST_TYPE=lint
+deploy:
+  provider: pypi
+  user: syrusakbary
+  on:
+    tags: true
+  password:
+    secure: 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

README.md

@@ -83,3 +83,21 @@ After developing, the full test suite can be evaluated by running:
 ```sh
 python setup.py test # Use --pytest-args="-v -s" for verbose mode
 ```
+
+
+### Documentation
+
+The documentation is generated using the excellent [Sphinx](http://www.sphinx-doc.org/) and a custom theme.
+
+The documentation dependencies are installed by running:
+
+```sh
+cd docs
+pip install -r requirements.txt
+```
+
+Then to produce a HTML version of the documentation:
+
+```sh
+make html
+```

README.rst

@@ -1,37 +1,38 @@
-Please read `UPGRADE-v1.0.md`_ to learn how to upgrade to Graphene ``1.0``.
+Please read `UPGRADE-v1.0.md </UPGRADE-v1.0.md>`__ to learn how to
+upgrade to Graphene ``1.0``.
 
 --------------
 
-|Graphene Logo| `Graphene`_ |Build Status| |PyPI version| |Coverage Status|
-===========================================================================
+|Graphene Logo| `Graphene <http://graphene-python.org>`__ |Build Status| |PyPI version| |Coverage Status|
+=========================================================================================================
 
-`Graphene`_ is a Python library for building GraphQL schemas/types fast
-and easily.
+`Graphene <http://graphene-python.org>`__ is a Python library for
+building GraphQL schemas/types fast and easily.
 
 -  **Easy to use:** Graphene helps you use GraphQL in Python without
    effort.
 -  **Relay:** Graphene has builtin support for Relay
 -  **Data agnostic:** Graphene supports any kind of data source: SQL
-   (Django, SQLAlchemy), NoSQL, custom Python objects, etc. We believe that
-   by providing a complete API you could plug Graphene anywhere your
-   data lives and make your data available through GraphQL.
+   (Django, SQLAlchemy), NoSQL, custom Python objects, etc. We believe
+   that by providing a complete API you could plug Graphene anywhere
+   your data lives and make your data available through GraphQL.
 
 Integrations
 ------------
 
 Graphene has multiple integrations with different frameworks:
 
-+---------------------+-------------------------------------+
-| integration         | Package                             |
-+=====================+=====================================+
-| Django              | `graphene-django`_                  |
-+---------------------+-------------------------------------+
-| SQLAlchemy          | `graphene-sqlalchemy`_              |
-+---------------------+-------------------------------------+
-| Google App Engine   | `graphene-gae`_                     |
-+---------------------+-------------------------------------+
-| Peewee              | *In progress* (`Tracking Issue`_)   |
-+---------------------+-------------------------------------+
++---------------------+----------------------------------------------------------------------------------------------+
+| integration         | Package                                                                                      |
++=====================+==============================================================================================+
+| Django              | `graphene-django <https://github.com/graphql-python/graphene-django/>`__                     |
++---------------------+----------------------------------------------------------------------------------------------+
+| SQLAlchemy          | `graphene-sqlalchemy <https://github.com/graphql-python/graphene-sqlalchemy/>`__             |
++---------------------+----------------------------------------------------------------------------------------------+
+| Google App Engine   | `graphene-gae <https://github.com/graphql-python/graphene-gae/>`__                           |
++---------------------+----------------------------------------------------------------------------------------------+
+| Peewee              | *In progress* (`Tracking Issue <https://github.com/graphql-python/graphene/issues/289>`__)   |
++---------------------+----------------------------------------------------------------------------------------------+
 
 Installation
 ------------
@@ -45,7 +46,8 @@ For instaling graphene, just run this command in your shell
 1.0 Upgrade Guide
 -----------------
 
-Please read `UPGRADE-v1.0.md`_ to learn how to upgrade.
+Please read `UPGRADE-v1.0.md </UPGRADE-v1.0.md>`__ to learn how to
+upgrade.
 
 Examples
 --------
@@ -74,10 +76,11 @@ Then Querying ``graphene.Schema`` is as simple as:
     result = schema.execute(query)
 
 If you want to learn even more, you can also check the following
-`examples`_:
+`examples <examples/>`__:
 
--  **Basic Schema**: `Starwars example`_
--  **Relay Schema**: `Starwars Relay example`_
+-  **Basic Schema**: `Starwars example <examples/starwars>`__
+-  **Relay Schema**: `Starwars Relay
+   example <examples/starwars_relay>`__
 
 Contributing
 ------------
@@ -94,15 +97,24 @@ After developing, the full test suite can be evaluated by running:
 
     python setup.py test # Use --pytest-args="-v -s" for verbose mode
 
-.. _UPGRADE-v1.0.md: /UPGRADE-v1.0.md
-.. _Graphene: http://graphene-python.org
-.. _graphene-django: https://github.com/graphql-python/graphene-django/
-.. _graphene-sqlalchemy: https://github.com/graphql-python/graphene-sqlalchemy/
-.. _graphene-gae: https://github.com/graphql-python/graphene-gae/
-.. _Tracking Issue: https://github.com/graphql-python/graphene/issues/289
-.. _examples: examples/
-.. _Starwars example: examples/starwars
-.. _Starwars Relay example: examples/starwars_relay
+Documentation
+~~~~~~~~~~~~~
+
+The documentation is generated using the excellent
+`Sphinx <http://www.sphinx-doc.org/>`__ and a custom theme.
+
+The documentation dependencies are installed by running:
+
+.. code:: sh
+
+    cd docs
+    pip install -r requirements.txt
+
+Then to produce a HTML version of the documentation:
+
+.. code:: sh
+
+    make html
 
 .. |Graphene Logo| image:: http://graphene-python.org/favicon.png
 .. |Build Status| image:: https://travis-ci.org/graphql-python/graphene.svg?branch=master

docs/Makefile

@@ -223,3 +223,7 @@ dummy:
 	$(SPHINXBUILD) -b dummy $(ALLSPHINXOPTS) $(BUILDDIR)/dummy
 	@echo
 	@echo "Build finished. Dummy builder generates no files."
+
+.PHONY: livehtml
+livehtml:
+	sphinx-autobuild -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html

docs/execution/index.rst

@@ -2,6 +2,38 @@
 Execution
 =========
 
+For executing a query a schema, you can directly call the ``execute`` method on it.
+
+
+.. code:: python
+    
+    schema = graphene.Schema(...)
+    result = schema.execute('{ name }')
+
+``result`` represents he result of execution. ``result.data`` is the result of executing the query, ``result.errors`` is ``None`` if no errors occurred, and is a non-empty list if an error occurred.
+
+
+Context
+_______
+
+You can pass context to a query via ``context_value``.
+
+
+.. code:: python
+
+    class Query(graphene.ObjectType):
+        name = graphene.String()
+
+        def resolve_name(self, args, context, info):
+            return context.get('name')
+    
+    schema = graphene.Schema(Query)
+    result = schema.execute('{ name }', context_value={'name': 'Syrus'})
+
+
+Middleware
+__________
+
 .. toctree::
    :maxdepth: 1
 

docs/types/mutations.rst

@@ -76,3 +76,69 @@ We should receive:
             "ok": true
         }
     }
+
+InputFields and InputObjectTypes
+----------------------
+InputFields are used in mutations to allow nested input data for mutations
+
+To use an InputField you define an InputObjectType that specifies the structure of your input data
+
+
+
+
+.. code:: python
+
+    import graphene
+
+    class PersonInput(graphene.InputObjectType):
+        name = graphene.String()
+        age = graphene.Int()
+
+    class CreatePerson(graphene.Mutation):
+        class Input:
+            person_data = graphene.InputField(PersonInput)
+
+        person = graphene.Field(lambda: Person)
+
+        def mutate(self, args, context, info):
+            p_data = args.get('person_data')
+
+            name = p_data.get('name')
+            age = p_data.get('age')
+
+            person = Person(name=name, age=age)
+            return CreatePerson(person=person)
+
+
+Note that  **name** and **age** are part of **person_data** now
+
+Using the above mutation your new query would look like this:
+
+.. code:: graphql
+
+    mutation myFirstMutation {
+        createPerson(personData: {name:"Peter", age: 24}) {
+            person {
+                name,
+                age
+            }
+        }
+    }
+
+InputObjectTypes can also be fields of InputObjectTypes allowing you to have
+as complex of input data as you need
+
+.. code:: python
+
+    import graphene
+
+    class LatLngInput(graphene.InputObjectType):
+        lat = graphene.Float()
+        lng = graphene.Float()
+
+    #A location has a latlng associated to it
+    class LocationInput(graphene.InputObjectType):
+        name = graphene.String()
+        latlng = graphene.InputField(LatLngInputType)
+
+

examples/context_example.py

@@ -0,0 +1,39 @@
+import graphene
+
+
+class User(graphene.ObjectType):
+    id = graphene.ID()
+    name = graphene.String()
+
+
+class Query(graphene.ObjectType):
+    me = graphene.Field(User)
+
+    def resolve_me(self, args, context, info):
+        return context['user']
+
+schema = graphene.Schema(query=Query)
+query = '''
+    query something{
+      me {
+        id
+        name
+      }
+    }
+'''
+
+
+def test_query():
+    result = schema.execute(query, context_value={'user': User(id='1', name='Syrus')})
+    assert not result.errors
+    assert result.data == {
+        'me': {
+            'id': '1',
+            'name': 'Syrus',
+        }
+    }
+
+
+if __name__ == '__main__':
+    result = schema.execute(query, context_value={'user': User(id='X', name='Console')})
+    print(result.data['me'])

graphene/__init__.py

@@ -10,7 +10,7 @@ except NameError:
     __SETUP__ = False
 
 
-VERSION = (1, 0, 2, 'final', 0)
+VERSION = (1, 1, 0, 'final', 0)
 
 __version__ = get_version(VERSION)
 

graphene/relay/connection.py

@@ -116,7 +116,7 @@ class IterableConnectionField(Field):
             connection_type = type
         assert issubclass(connection_type, Connection), (
             '{} type have to be a subclass of Connection. Received "{}".'
-        ).format(str(self), connection_type)
+        ).format(self.__class__.__name__, connection_type)
         return connection_type
 
     @classmethod
@@ -152,4 +152,5 @@ class IterableConnectionField(Field):
         resolver = super(IterableConnectionField, self).get_resolver(parent_resolver)
         return partial(self.connection_resolver, resolver, self.type)
 
+
 ConnectionField = IterableConnectionField

graphene/relay/node.py

@@ -12,9 +12,9 @@ def is_node(objecttype):
     '''
     Check if the given objecttype has Node as an interface
     '''
-    assert issubclass(objecttype, ObjectType), (
-        'Only ObjectTypes can have a Node interface. Received %s'
-    ) % objecttype
+    if not issubclass(objecttype, ObjectType):
+        return False
+
     for i in objecttype._meta.interfaces:
         if issubclass(i, Node):
             return True
@@ -35,17 +35,19 @@ def get_default_connection(cls):
 
 class GlobalID(Field):
 
-    def __init__(self, node=None, required=True, *args, **kwargs):
+    def __init__(self, node=None, parent_type=None, required=True, *args, **kwargs):
         super(GlobalID, self).__init__(ID, required=required, *args, **kwargs)
         self.node = node or Node
+        self.parent_type_name = parent_type._meta.name if parent_type else None
 
     @staticmethod
-    def id_resolver(parent_resolver, node, root, args, context, info):
-        id = parent_resolver(root, args, context, info)
-        return node.to_global_id(info.parent_type.name, id)  # root._meta.name
+    def id_resolver(parent_resolver, node, root, args, context, info, parent_type_name=None):
+        type_id = parent_resolver(root, args, context, info)
+        parent_type_name = parent_type_name or info.parent_type.name
+        return node.to_global_id(parent_type_name, type_id)  # root._meta.name
 
     def get_resolver(self, parent_resolver):
-        return partial(self.id_resolver, parent_resolver, self.node)
+        return partial(self.id_resolver, parent_resolver, self.node, parent_type_name=self.parent_type_name)
 
 
 class NodeMeta(InterfaceMeta):

graphene/relay/tests/test_global_id.py

@@ -1,6 +1,8 @@
-from ..node import Node, GlobalID
+from graphql_relay import to_global_id
 
-from ...types import NonNull, ID
+from ..node import Node, GlobalID
+from ...types import NonNull, ID, ObjectType, String
+from ...types.definitions import GrapheneObjectType
 
 
 class CustomNode(Node):
@@ -9,6 +11,26 @@ class CustomNode(Node):
         name = 'Node'
 
 
+class User(ObjectType):
+
+    class Meta:
+        interfaces = [CustomNode]
+    name = String()
+
+
+class Info(object):
+
+    def __init__(self, parent_type):
+        self.parent_type = GrapheneObjectType(
+            graphene_type=parent_type,
+            name=parent_type._meta.name,
+            description=parent_type._meta.description,
+            fields=None,
+            is_type_of=parent_type.is_type_of,
+            interfaces=None
+        )
+
+
 def test_global_id_defaults_to_required_and_node():
     gid = GlobalID()
     assert isinstance(gid.type, NonNull)
@@ -20,3 +42,19 @@ def test_global_id_allows_overriding_of_node_and_required():
     gid = GlobalID(node=CustomNode, required=False)
     assert gid.type == ID
     assert gid.node == CustomNode
+
+
+def test_global_id_defaults_to_info_parent_type():
+    my_id = '1'
+    gid = GlobalID()
+    id_resolver = gid.get_resolver(lambda *_: my_id)
+    my_global_id = id_resolver(None, None, None, Info(User))
+    assert my_global_id == to_global_id(User._meta.name, my_id)
+
+
+def test_global_id_allows_setting_customer_parent_type():
+    my_id = '1'
+    gid = GlobalID(parent_type=User)
+    id_resolver = gid.get_resolver(lambda *_: my_id)
+    my_global_id = id_resolver(None, None, None, None)
+    assert my_global_id == to_global_id(User._meta.name, my_id)

graphene/tests/issues/test_313.py

@@ -0,0 +1,52 @@
+# https://github.com/graphql-python/graphene/issues/313
+
+import graphene
+from graphene import resolve_only_args
+
+class Success(graphene.ObjectType):
+    yeah = graphene.String()
+
+
+class Error(graphene.ObjectType):
+    message = graphene.String()
+
+
+class CreatePostResult(graphene.Union):
+    class Meta:
+        types = [Success, Error]
+
+
+class CreatePost(graphene.Mutation):
+    class Input:
+        text = graphene.String(required=True)
+
+    result = graphene.Field(CreatePostResult)
+
+    @resolve_only_args
+    def mutate(self, text):
+        result = Success(yeah='yeah')
+
+        return CreatePost(result=result)
+
+
+class Mutations(graphene.ObjectType):
+    create_post = CreatePost.Field()
+
+# tests.py
+
+def test_create_post():
+    query_string = '''
+    mutation {
+      createPost(text: "Try this out") {
+        result {
+          __typename
+        }
+      }
+    }
+    '''
+
+    schema = graphene.Schema(mutation=Mutations)
+    result = schema.execute(query_string)
+
+    assert not result.errors
+    assert result.data['createPost']['result']['__typename'] == 'Success'

graphene/tests/issues/test_356.py

@@ -0,0 +1,24 @@
+# https://github.com/graphql-python/graphene/issues/356
+
+import pytest
+import graphene
+from graphene import relay
+
+class SomeTypeOne(graphene.ObjectType):
+    pass
+
+class SomeTypeTwo(graphene.ObjectType):
+    pass
+
+class MyUnion(graphene.Union):
+    class Meta:
+        types = (SomeTypeOne, SomeTypeTwo)
+
+def test_issue():
+    with pytest.raises(Exception) as exc_info:
+        class Query(graphene.ObjectType):
+            things = relay.ConnectionField(MyUnion)
+
+        schema = graphene.Schema(query=Query)
+
+    assert str(exc_info.value) == 'IterableConnectionField type have to be a subclass of Connection. Received "MyUnion".'

graphene/types/argument.py

@@ -28,9 +28,14 @@ class Argument(OrderedType):
         )
 
 
-def to_arguments(args, extra_args):
+def to_arguments(args, extra_args=None):
     from .unmountedtype import UnmountedType
-    extra_args = sorted(extra_args.items(), key=lambda f: f[1])
+    from .field import Field
+    from .inputfield import InputField
+    if extra_args:
+        extra_args = sorted(extra_args.items(), key=lambda f: f[1])
+    else:
+        extra_args = []
     iter_arguments = chain(args.items(), extra_args)
     arguments = OrderedDict()
     for default_name, arg in iter_arguments:
@@ -44,6 +49,13 @@ def to_arguments(args, extra_args):
         if isinstance(arg, UnmountedType):
             arg = arg.Argument()
 
+        if isinstance(arg, (InputField, Field)):
+            raise ValueError('Expected {} to be Argument, but received {}. Try using Argument({}).'.format(
+                default_name,
+                type(arg).__name__,
+                arg.type
+            ))
+
         if not isinstance(arg, Argument):
             raise ValueError('Unknown argument "{}".'.format(default_name))
 

graphene/types/scalars.py

@@ -49,6 +49,7 @@ class Scalar(six.with_metaclass(ScalarTypeMeta, UnmountedType)):
         '''
         return cls
 
+
 # As per the GraphQL Spec, Integers are only treated as valid when a valid
 # 32-bit signed integer, providing the broadest support across platforms.
 #

graphene/types/structures.py

@@ -9,6 +9,15 @@ class Structure(UnmountedType):
 
     def __init__(self, of_type, *args, **kwargs):
         super(Structure, self).__init__(*args, **kwargs)
+        if not isinstance(of_type, Structure) and isinstance(of_type, UnmountedType):
+            cls_name = type(self).__name__
+            of_type_name = type(of_type).__name__
+            raise Exception("{} could not have a mounted {}() as inner type. Try with {}({}).".format(
+                cls_name,
+                of_type_name,
+                cls_name,
+                of_type_name,
+            ))
         self.of_type = of_type
 
     def get_type(self):
@@ -56,7 +65,7 @@ class NonNull(Structure):
         super(NonNull, self).__init__(*args, **kwargs)
         assert not isinstance(self.of_type, NonNull), (
             'Can only create NonNull of a Nullable GraphQLType but got: {}.'
-        ).format(type)
+        ).format(self.of_type)
 
     def __str__(self):
         return '{}!'.format(self.of_type)

graphene/types/tests/test_argument.py

@@ -1,6 +1,8 @@
 import pytest
 
-from ..argument import Argument
+from ..argument import Argument, to_arguments
+from ..field import Field
+from ..inputfield import InputField
 from ..structures import NonNull
 from ..scalars import String
 
@@ -24,3 +26,38 @@ def test_argument_comparasion():
 def test_argument_required():
     arg = Argument(String, required=True)
     assert arg.type == NonNull(String)
+
+
+def test_to_arguments():
+    args = {
+        'arg_string': Argument(String),
+        'unmounted_arg': String(required=True)
+    }
+
+    my_args = to_arguments(args)
+    assert my_args == {
+        'arg_string': Argument(String),
+        'unmounted_arg': Argument(String, required=True)
+    }
+
+
+def test_to_arguments_raises_if_field():
+    args = {
+        'arg_string': Field(String),
+    }
+
+    with pytest.raises(ValueError) as exc_info:
+        to_arguments(args)
+    
+    assert str(exc_info.value) == 'Expected arg_string to be Argument, but received Field. Try using Argument(String).'
+
+
+def test_to_arguments_raises_if_inputfield():
+    args = {
+        'arg_string': InputField(String),
+    }
+
+    with pytest.raises(ValueError) as exc_info:
+        to_arguments(args)
+    
+    assert str(exc_info.value) == 'Expected arg_string to be Argument, but received InputField. Try using Argument(String).'

graphene/types/tests/test_structures.py

@@ -10,12 +10,51 @@ def test_list():
     assert str(_list) == '[String]'
 
 
+def test_list_with_unmounted_type():
+    with pytest.raises(Exception) as exc_info:
+        List(String())
+    
+    assert str(exc_info.value) == 'List could not have a mounted String() as inner type. Try with List(String).'
+
+
+def test_list_inherited_works_list():
+    _list = List(List(String))
+    assert isinstance(_list.of_type, List)
+    assert _list.of_type.of_type == String
+
+
+def test_list_inherited_works_nonnull():
+    _list = List(NonNull(String))
+    assert isinstance(_list.of_type, NonNull)
+    assert _list.of_type.of_type == String
+
+
 def test_nonnull():
     nonnull = NonNull(String)
     assert nonnull.of_type == String
     assert str(nonnull) == 'String!'
 
 
+def test_nonnull_inherited_works_list():
+    _list = NonNull(List(String))
+    assert isinstance(_list.of_type, List)
+    assert _list.of_type.of_type == String
+
+
+def test_nonnull_inherited_dont_work_nonnull():
+    with pytest.raises(Exception) as exc_info:
+        NonNull(NonNull(String))
+    
+    assert str(exc_info.value) == 'Can only create NonNull of a Nullable GraphQLType but got: String!.'
+
+
+def test_nonnull_with_unmounted_type():
+    with pytest.raises(Exception) as exc_info:
+        NonNull(String())
+    
+    assert str(exc_info.value) == 'NonNull could not have a mounted String() as inner type. Try with NonNull(String).'
+
+
 def test_list_comparasion():
     list1 = List(String)
     list2 = List(String)

graphene/types/union.py

@@ -53,7 +53,11 @@ class Union(six.with_metaclass(UnionMeta)):
     to determine which type is actually used when the field is resolved.
     '''
 
-    resolve_type = None
+    @classmethod
+    def resolve_type(cls, instance, context, info):
+        from .objecttype import ObjectType
+        if isinstance(instance, ObjectType):
+            return type(instance)
 
     def __init__(self, *args, **kwargs):
         raise Exception("A Union cannot be intitialized")