mirror of
https://github.com/graphql-python/graphene.git
synced 2024-11-14 13:46:54 +03:00
101 lines
2.2 KiB
ReStructuredText
101 lines
2.2 KiB
ReStructuredText
Enums
|
|
=====
|
|
|
|
An ``Enum`` is a special ``GraphQL`` type that represents a set of
|
|
symbolic names (members) bound to unique, constant values.
|
|
|
|
Definition
|
|
----------
|
|
|
|
You can create an ``Enum`` using classes:
|
|
|
|
.. code:: python
|
|
|
|
import graphene
|
|
|
|
class Episode(graphene.Enum):
|
|
NEWHOPE = 4
|
|
EMPIRE = 5
|
|
JEDI = 6
|
|
|
|
But also using instances of Enum:
|
|
|
|
.. code:: python
|
|
|
|
Episode = graphene.Enum('Episode', [('NEWHOPE', 4), ('EMPIRE', 5), ('JEDI', 6)])
|
|
|
|
Value descriptions
|
|
------------------
|
|
|
|
It's possible to add a description to an enum value, for that the enum value
|
|
needs to have the ``description`` property on it.
|
|
|
|
.. code:: python
|
|
|
|
class Episode(graphene.Enum):
|
|
NEWHOPE = 4
|
|
EMPIRE = 5
|
|
JEDI = 6
|
|
|
|
@property
|
|
def description(self):
|
|
if self == Episode.NEWHOPE:
|
|
return 'New Hope Episode'
|
|
return 'Other episode'
|
|
|
|
|
|
Usage with Python Enums
|
|
-----------------------
|
|
|
|
In case the Enums are already defined it's possible to reuse them using
|
|
the ``Enum.from_enum`` function.
|
|
|
|
.. code:: python
|
|
|
|
graphene.Enum.from_enum(AlreadyExistingPyEnum)
|
|
|
|
``Enum.from_enum`` supports a ``description`` and ``deprecation_reason`` lambdas as input so
|
|
you can add description etc. to your enum without changing the original:
|
|
|
|
.. code:: python
|
|
|
|
graphene.Enum.from_enum(
|
|
AlreadyExistingPyEnum,
|
|
description=lambda v: return 'foo' if v == AlreadyExistingPyEnum.Foo else 'bar')
|
|
|
|
|
|
Notes
|
|
-----
|
|
|
|
``graphene.Enum`` uses |enum.Enum|_ internally (or a backport if
|
|
that's not available) and can be used in a similar way, with the exception of
|
|
member getters.
|
|
|
|
In the Python ``Enum`` implementation you can access a member by initing the Enum.
|
|
|
|
.. code:: python
|
|
|
|
from enum import Enum
|
|
class Color(Enum):
|
|
RED = 1
|
|
GREEN = 2
|
|
BLUE = 3
|
|
|
|
assert Color(1) == Color.RED
|
|
|
|
|
|
However, in Graphene ``Enum`` you need to call get to have the same effect:
|
|
|
|
.. code:: python
|
|
|
|
from graphene import Enum
|
|
class Color(Enum):
|
|
RED = 1
|
|
GREEN = 2
|
|
BLUE = 3
|
|
|
|
assert Color.get(1) == Color.RED
|
|
|
|
.. |enum.Enum| replace:: ``enum.Enum``
|
|
.. _enum.Enum: https://docs.python.org/3/library/enum.html
|