graphene/graphene/types/structures.py

84 lines
2.6 KiB
Python

from .unmountedtype import UnmountedType
from .utils import get_type
class Structure(UnmountedType):
'''
A structure is a GraphQL type instance that
wraps a main type with certain structure.
'''
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
@property
def of_type(self):
return get_type(self._of_type)
def get_type(self):
'''
This function is called when the unmounted type (List or NonNull instance)
is mounted (as a Field, InputField or Argument)
'''
return self
class List(Structure):
'''
List Modifier
A list is a kind of type marker, a wrapping type which points to another
type. Lists are often created within the context of defining the fields of
an object type.
'''
def __str__(self):
return '[{}]'.format(self.of_type)
def __eq__(self, other):
return isinstance(other, List) and (
self.of_type == other.of_type and
self.args == other.args and
self.kwargs == other.kwargs
)
class NonNull(Structure):
'''
Non-Null Modifier
A non-null is a kind of type marker, a wrapping type which points to another
type. Non-null types enforce that their values are never null and can ensure
an error is raised if this ever occurs during a request. It is useful for
fields which you can make a strong guarantee on non-nullability, for example
usually the id field of a database row will never be null.
Note: the enforcement of non-nullability occurs within the executor.
'''
def __init__(self, *args, **kwargs):
super(NonNull, self).__init__(*args, **kwargs)
assert not isinstance(self._of_type, NonNull), (
'Can only create NonNull of a Nullable GraphQLType but got: {}.'
).format(self._of_type)
def __str__(self):
return '{}!'.format(self.of_type)
def __eq__(self, other):
return isinstance(other, NonNull) and (
self.of_type == other.of_type and
self.args == other.args and
self.kwargs == other.kwargs
)