graphene/graphene/relay/node.py
2017-10-28 10:59:13 -07:00

130 lines
4.0 KiB
Python

from functools import partial
import six
from graphql_relay import from_global_id, to_global_id
from ..types import ID, Field, Interface, ObjectType
from ..types.utils import get_type
from ..types.interface import InterfaceMeta
def is_node(objecttype):
'''
Check if the given objecttype has Node as an interface
'''
if not issubclass(objecttype, ObjectType):
return False
for i in objecttype._meta.interfaces:
if issubclass(i, Node):
return True
return False
def get_default_connection(cls):
from .connection import Connection
assert issubclass(cls, ObjectType), (
'Can only get connection type on implemented Nodes.'
)
class Meta:
node = cls
return type('{}Connection'.format(cls.__name__), (Connection,), {'Meta': Meta})
class GlobalID(Field):
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, 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, parent_type_name=self.parent_type_name)
class NodeMeta(InterfaceMeta):
def __new__(cls, name, bases, attrs):
cls = InterfaceMeta.__new__(cls, name, bases, attrs)
cls._meta.fields['id'] = GlobalID(
cls, description='The ID of the object.')
return cls
class NodeField(Field):
def __init__(self, node, type=False, deprecation_reason=None,
name=None, **kwargs):
assert issubclass(node, Node), 'NodeField can only operate in Nodes'
self.node_type = node
self.field_type = type
super(NodeField, self).__init__(
# If we don's specify a type, the field type will be the node
# interface
type or node,
description='The ID of the object',
id=ID(required=True)
)
def get_resolver(self, parent_resolver):
return partial(self.node_type.node_resolver, only_type=get_type(self.field_type))
class Node(six.with_metaclass(NodeMeta, Interface)):
'''An object with an ID'''
@classmethod
def Field(cls, *args, **kwargs): # noqa: N802
return NodeField(cls, *args, **kwargs)
@classmethod
def node_resolver(cls, root, args, context, info, only_type=None):
return cls.get_node_from_global_id(args.get('id'), context, info, only_type)
@classmethod
def get_node_from_global_id(cls, global_id, context, info, only_type=None):
try:
_type, _id = cls.from_global_id(global_id)
graphene_type = info.schema.get_type(_type).graphene_type
except Exception:
return None
if only_type:
assert graphene_type == only_type, (
'Must receive an {} id.'
).format(graphene_type._meta.name)
# We make sure the ObjectType implements the "Node" interface
if cls not in graphene_type._meta.interfaces:
return None
get_node = getattr(graphene_type, 'get_node', None)
if get_node:
return get_node(_id, context, info)
@classmethod
def from_global_id(cls, global_id):
return from_global_id(global_id)
@classmethod
def to_global_id(cls, type, id):
return to_global_id(type, id)
@classmethod
def implements(cls, objecttype):
get_connection = getattr(objecttype, 'get_connection', None)
if not get_connection:
get_connection = partial(get_default_connection, objecttype)
objecttype.Connection = get_connection()