Added relay.Connection and relay.ConnectionField

graphene/relay/__init__.py

@@ -1,10 +1,10 @@
 from .node import Node
 # from .mutation import ClientIDMutation
-# from .connection import Connection, ConnectionField
+from .connection import Connection, ConnectionField
 
 __all__ = [
     'Node',
     # 'ClientIDMutation',
-    # 'Connection',
-    # 'ConnectionField',
+    'Connection',
+    'ConnectionField',
 ]

graphene/relay/connection.py

@@ -0,0 +1,155 @@
+import re
+from collections import Iterable, OrderedDict
+from functools import partial
+
+import six
+
+from graphql_relay import connection_from_list
+from graphql_relay.connection.connection import connection_args
+
+from ..types import Boolean, String, List
+from ..types.field import Field
+from ..types.objecttype import ObjectType, ObjectTypeMeta
+from ..types.options import Options
+from ..utils.is_base_type import is_base_type
+from ..utils.props import props
+from .node import Node
+
+from ..types.utils import get_fields_in_type, yank_fields_from_attrs, merge_fields_in_attrs
+
+
+def is_node(objecttype):
+    for i in objecttype._meta.interfaces:
+        if issubclass(i, Node):
+            return True
+    return False
+
+
+class PageInfo(ObjectType):
+    has_next_page = Boolean(
+        required=True,
+        name='hasNextPage',
+        description='When paginating forwards, are there more items?',
+    )
+
+    has_previous_page = Boolean(
+        required=True,
+        name='hasPreviousPage',
+        description='When paginating backwards, are there more items?',
+    )
+
+    start_cursor = String(
+        name='startCursor',
+        description='When paginating backwards, the cursor to continue.',
+    )
+
+    end_cursor = String(
+        name='endCursor',
+        description='When paginating forwards, the cursor to continue.',
+    )
+
+
+class ConnectionMeta(ObjectTypeMeta):
+
+    def __new__(cls, name, bases, attrs):
+        # Also ensure initialization is only performed for subclasses of Model
+        # (excluding Model class itself).
+        if not is_base_type(bases, ConnectionMeta):
+            return type.__new__(cls, name, bases, attrs)
+
+        options = Options(
+            attrs.pop('Meta', None),
+            name=None,
+            description=None,
+            node=None,
+        )
+        options.interfaces = ()
+
+        assert options.node, 'You have to provide a node in {}.Meta'.format(cls.__name__)
+        assert issubclass(options.node, (Node, ObjectType)), (
+            'Received incompatible node "{}" for Connection {}.'
+        ).format(options.node, name)
+
+        base_name = re.sub('Connection$', '', name)
+        if not options.name:
+            options.name = '{}Connection'.format(base_name)
+
+
+        edge_class = attrs.pop('Edge', None)
+        edge_fields = OrderedDict([
+            ('node', Field(options.node, description='The item at the end of the edge')),
+            ('cursor', Field(String, required=True, description='A cursor for use in pagination'))
+        ])
+        edge_attrs = props(edge_class) if edge_class else OrderedDict()
+        edge_fields.update(get_fields_in_type(ObjectType, edge_attrs))
+        EdgeMeta = type('Meta', (object, ), {'fields': edge_fields})
+        Edge = type('{}Edge'.format(base_name), (ObjectType,), {'Meta': EdgeMeta})
+
+        options.local_fields = OrderedDict([
+            ('page_info', Field(PageInfo, name='pageInfo', required=True)),
+            ('edges', Field(List(Edge)))
+        ])
+        typed_fields = get_fields_in_type(ObjectType, attrs)
+        options.local_fields.update(typed_fields)
+        options.fields = options.local_fields
+        yank_fields_from_attrs(attrs, typed_fields)
+
+        return type.__new__(cls, name, bases, dict(attrs, _meta=options, Edge=Edge))
+
+
+class Connection(six.with_metaclass(ConnectionMeta, ObjectType)):
+    resolve_node = None
+    resolve_cursor = None
+
+    def __init__(self, *args, **kwargs):
+        kwargs['pageInfo'] = kwargs.pop('pageInfo', kwargs.pop('page_info'))
+        super(Connection, self).__init__(*args, **kwargs)
+
+
+class IterableConnectionField(Field):
+
+    def __init__(self, type, *args, **kwargs):
+        # arguments = kwargs.pop('args', {})
+        # if not arguments:
+        #     arguments = connection_args
+        # else:
+        #     arguments = copy.copy(arguments)
+        #     arguments.update(connection_args)
+
+        super(IterableConnectionField, self).__init__(
+            type,
+            args=connection_args,
+            *args,
+            **kwargs
+        )
+
+    @property
+    def connection(self):
+        if is_node(self.type):
+            connection_type = self.type.Connection
+        else:
+            connection_type = self.type
+        assert issubclass(connection_type, Connection), (
+            '{} type have to be a subclass of Connection'
+        ).format(str(self))
+        return connection_type
+
+    @staticmethod
+    def connection_resolver(resolver, connection, root, args, context, info):
+        iterable = resolver(root, args, context, info)
+        assert isinstance(iterable, Iterable), (
+            'Resolved value from the connection field have to be iterable. '
+            'Received "{}"'
+        ).format(iterable)
+        connection = connection_from_list(
+            iterable,
+            args,
+            connection_type=connection,
+            edge_type=connection.Edge,
+        )
+        return connection
+
+    def get_resolver(self, parent_resolver):
+        return partial(self.connection_resolver, parent_resolver, self.connection)
+
+ConnectionField = IterableConnectionField

graphene/relay/tests/test_connection.py

@@ -0,0 +1,66 @@
+
+from ...types import ObjectType, Schema, List, Field, String, NonNull
+from ..connection import Connection, PageInfo
+from ..node import Node
+
+
+class MyObject(ObjectType):
+    class Meta:
+        interfaces = [Node]
+    field = String()
+
+    @classmethod
+    def get_node(cls, id):
+        pass
+
+
+class MyObjectConnection(Connection):
+    extra = String()
+
+    class Meta:
+        node = MyObject
+
+    class Edge:
+        other = String()
+
+
+class RootQuery(ObjectType):
+    my_connection = Field(MyObjectConnection)
+
+
+schema = Schema(query=RootQuery)
+
+
+def test_connection():
+    assert MyObjectConnection._meta.name == 'MyObjectConnection'
+    fields = MyObjectConnection._meta.fields
+    assert fields.keys() == ['page_info', 'edges', 'extra']
+    edge_field = fields['edges']
+    pageinfo_field = fields['page_info']
+
+    assert isinstance(edge_field, Field)
+    assert isinstance(edge_field.type, List)
+    assert edge_field.type.of_type == MyObjectConnection.Edge
+
+    assert isinstance(pageinfo_field, Field)
+    assert isinstance(pageinfo_field.type, NonNull)
+    assert pageinfo_field.type.of_type == PageInfo
+
+
+def test_edge():
+    Edge = MyObjectConnection.Edge
+    assert Edge._meta.name == 'MyObjectEdge'
+    edge_fields = Edge._meta.fields
+    assert edge_fields.keys() == ['node', 'cursor', 'other']
+
+    assert isinstance(edge_fields['node'], Field)
+    assert edge_fields['node'].type == MyObject
+
+    assert isinstance(edge_fields['other'], Field)
+    assert edge_fields['other'].type == String
+
+
+def test_pageinfo():
+    assert PageInfo._meta.name == 'PageInfo'
+    fields = PageInfo._meta.fields
+    assert fields.keys() == ['has_next_page', 'has_previous_page', 'start_cursor', 'end_cursor']

graphene/types/field.py

@@ -44,3 +44,6 @@ class Field(OrderedType):
         if inspect.isfunction(self._type):
             return self._type()
         return self._type
+
+    def get_resolver(self, parent_resolver):
+        return self.resolver or parent_resolver

graphene/types/objecttype.py

@@ -22,6 +22,7 @@ class ObjectTypeMeta(AbstractTypeMeta):
             name=name,
             description=attrs.get('__doc__'),
             interfaces=(),
+            fields=OrderedDict(),
         )
 
         attrs = merge_fields_in_attrs(bases, attrs)
@@ -33,7 +34,7 @@ class ObjectTypeMeta(AbstractTypeMeta):
                 'All interfaces of {} must be a subclass of Interface. Received "{}".'
             ).format(name, interface)
             options.interface_fields.update(interface._meta.fields)
-        options.fields = OrderedDict(options.interface_fields)
+        options.fields.update(options.interface_fields)
         options.fields.update(options.local_fields)
 
         cls = type.__new__(cls, name, bases, dict(attrs, _meta=options))

graphene/types/tests/test_typemap.py

@@ -42,6 +42,7 @@ def test_objecttype():
     class MyObjectType(ObjectType):
         '''Description'''
         foo = String(bar=String(description='Argument description', default_value='x'), description='Field description')
+        bar = String(name='gizmo')
 
         def resolve_foo(self, args, info):
             return args.get('bar')
@@ -54,7 +55,7 @@ def test_objecttype():
     assert graphql_type.description == 'Description'
 
     fields = graphql_type.get_fields()
-    assert 'foo' in fields
+    assert fields.keys() == ['foo', 'gizmo']
     foo_field = fields['foo']
     assert isinstance(foo_field, GraphQLField)
     assert foo_field.description == 'Field description'

graphene/types/typemap.py

@@ -210,12 +210,12 @@ class TypeMap(GraphQLTypeMap):
                 _field = GraphQLField(
                     field_type,
                     args=args,
-                    resolver=field.resolver or cls.get_resolver_for_type(type, name),
+                    resolver=field.get_resolver(cls.get_resolver_for_type(type, name)),
                     deprecation_reason=field.deprecation_reason,
                     description=field.description
                 )
-            processed_name = cls.process_field_name(name)
-            fields[processed_name] = _field
+            field_name = field.name or cls.process_field_name(name)
+            fields[field_name] = _field
         return fields
 
     @classmethod