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from collections import OrderedDict
from functools import partial
from inspect import isclass
from graphql_relay import from_global_id, to_global_id
from ..types import ID, Field, Interface, ObjectType
from ..types.interface import InterfaceOptions
from ..types.utils import get_type
def is_node(objecttype):
"""
Check if the given objecttype has Node as an interface
"""
if not isclass(objecttype):
return False
if not issubclass(objecttype, ObjectType):
return False
for i in objecttype._meta.interfaces:
if issubclass(i, Node):
return True
return False
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, info, parent_type_name=None, **args):
type_id = parent_resolver(root, info, **args)
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 NodeField(Field):
def __init__(self, node, type=False, **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,
id=ID(required=True, description="The ID of the object"),
**kwargs
)
def get_resolver(self, parent_resolver):
return partial(self.node_type.node_resolver, get_type(self.field_type))
class AbstractNode(Interface):
class Meta:
abstract = True
@classmethod
def __init_subclass_with_meta__(cls, **options):
_meta = InterfaceOptions(cls)
_meta.fields = OrderedDict(
id=GlobalID(cls, description="The ID of the object.")
)
super(AbstractNode, cls).__init_subclass_with_meta__(_meta=_meta, **options)
class Node(AbstractNode):
"""An object with an ID"""
@classmethod
def Field(cls, *args, **kwargs): # noqa: N802
return NodeField(cls, *args, **kwargs)
@classmethod
def node_resolver(cls, only_type, root, info, id):
return cls.get_node_from_global_id(info, id, only_type=only_type)
@classmethod
def get_node_from_global_id(cls, info, global_id, 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 a {} id.").format(
only_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(info, _id)
@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)
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