Merge pull request #100 from graphql-python/features/enum

Add Enum type

Author: syrusakbary

.coveragerc

@@ -0,0 +1,2 @@
+[run]
+omit = graphene/utils/enum.py,graphene/contrib/django/debug/sql/tracking.py,*/tests/*

.travis.yml

@@ -23,7 +23,7 @@ before_install:
 install:
 - |
   if [ "$TEST_TYPE" = build ]; then
-    pip install --download-cache $HOME/.cache/pip/ pytest pytest-cov coveralls six pytest-django django-filter
+    pip install --download-cache $HOME/.cache/pip/ pytest pytest-cov coveralls six pytest-django django-filter sqlalchemy_utils
     pip install --download-cache $HOME/.cache/pip/ -e .[django]
     pip install --download-cache $HOME/.cache/pip/ -e .[sqlalchemy]
     pip install django==$DJANGO_VERSION

docs/config.toml

@@ -14,6 +14,7 @@ ga = "UA-12613282-7"
 	  "/docs/objecttypes/",
 	  "/docs/mutations/",
 	  "/docs/basic-types/",
+	  "/docs/enums/",
 	  "/docs/relay/",
 	]
 

docs/pages/docs/enums.md

@@ -0,0 +1,33 @@
+---
+title: Enums
+description: Walkthrough Enums
+---
+
+# Enums
+
+A `Enum` is a special `GraphQL` type that represents a set of symbolic names (members) bound to unique, constant values.
+
+## Enum definition
+
+You can create an `Enum` using classes:
+
+```python
+import graphene
+
+class Episode(graphene.Enum):
+    NEWHOPE = 4
+    EMPIRE = 5
+    JEDI = 6
+```
+
+But also using instances of Enum:
+
+```python
+Episode = graphene.Enum('Episode', [('NEWHOPE', 4), ('EMPIRE', 5), ('JEDI', 6)])
+```
+
+## Notes
+
+Internally, `graphene.Enum` uses [`enum.Enum`](https://docs.python.org/3/library/enum.html) Python implementation if available, or a backport if not.
+
+So you can use it in the same way as you would do with Python `enum.Enum`.

examples/starwars/schema.py

@@ -1,15 +1,13 @@
-from graphql.core.type import GraphQLEnumValue
-
 import graphene
 from graphene import resolve_only_args
 
 from .data import get_character, get_droid, get_hero, get_human
 
-Episode = graphene.Enum('Episode', dict(
-    NEWHOPE=GraphQLEnumValue(4),
-    EMPIRE=GraphQLEnumValue(5),
-    JEDI=GraphQLEnumValue(6)
-))
+
+class Episode(graphene.Enum):
+    NEWHOPE = 4
+    EMPIRE = 5
+    JEDI = 6
 
 
 class Character(graphene.Interface):

graphene/__init__.py

@@ -1,7 +1,3 @@
-from graphql.core.type import (
-    GraphQLEnumType as Enum
-)
-
 from graphene import signals
 
 from .core import (
@@ -11,6 +7,7 @@
     Interface,
     Mutation,
     Scalar,
+    Enum,
     InstanceType,
     LazyType,
     Argument,
@@ -58,6 +55,7 @@
     'Interface',
     'Mutation',
     'Scalar',
+    'Enum',
     'Field',
     'InputField',
     'StringField',

graphene/contrib/django/converter.py

@@ -1,12 +1,22 @@
 from django.db import models
 
 from ...core.types.scalars import ID, Boolean, Float, Int, String
+from ...core.classtypes.enum import Enum
 from .compat import RelatedObject, UUIDField
 from .utils import get_related_model, import_single_dispatch
 
 singledispatch = import_single_dispatch()
 
 
+def convert_django_field_with_choices(field):
+    choices = getattr(field, 'choices', None)
+    if choices:
+        meta = field.model._meta
+        name = '{}_{}_{}'.format(meta.app_label, meta.object_name, field.name)
+        return Enum(name.upper(), choices, description=field.help_text)
+    return convert_django_field(field)
+
+
 @singledispatch
 def convert_django_field(field):
     raise Exception(

graphene/contrib/django/tests/test_converter.py

@@ -2,7 +2,8 @@
 from py.test import raises
 
 import graphene
-from graphene.contrib.django.converter import convert_django_field
+from graphene.contrib.django.converter import (
+    convert_django_field, convert_django_field_with_choices)
 from graphene.contrib.django.fields import (ConnectionOrListField,
                                             DjangoModelField)
 
@@ -86,6 +87,26 @@ def test_should_nullboolean_convert_boolean():
     assert field.required is False
 
 
+def test_field_with_choices_convert_enum():
+    field = models.CharField(help_text='Language', choices=(
+        ('es', 'Spanish'),
+        ('en', 'English')
+    ))
+
+    class TranslatedModel(models.Model):
+        language = field
+
+        class Meta:
+            app_label = 'test'
+
+    graphene_type = convert_django_field_with_choices(field)
+    assert issubclass(graphene_type, graphene.Enum)
+    assert graphene_type._meta.type_name == 'TEST_TRANSLATEDMODEL_LANGUAGE'
+    assert graphene_type._meta.description == 'Language'
+    assert graphene_type.__enum__.__members__['es'].value == 'Spanish'
+    assert graphene_type.__enum__.__members__['en'].value == 'English'
+
+
 def test_should_float_convert_float():
     assert_conversion(models.FloatField, graphene.Float)
 

graphene/contrib/django/types.py

@@ -5,7 +5,7 @@
 
 from ...core.classtypes.objecttype import ObjectType, ObjectTypeMeta
 from ...relay.types import Connection, Node, NodeMeta
-from .converter import convert_django_field
+from .converter import convert_django_field_with_choices
 from .options import DjangoOptions
 from .utils import get_reverse_fields
 
@@ -29,7 +29,7 @@ def construct_fields(cls):
                 # We skip this field if we specify only_fields and is not
                 # in there. Or when we exclude this field in exclude_fields
                 continue
-            converted_field = convert_django_field(field)
+            converted_field = convert_django_field_with_choices(field)
             cls.add_to_class(field.name, converted_field)
 
     def construct(cls, *args, **kwargs):

graphene/contrib/sqlalchemy/converter.py

@@ -2,7 +2,13 @@
 
 from sqlalchemy import types
 from sqlalchemy.orm import interfaces
+try:
+    from sqlalchemy_utils.types.choice import ChoiceType
+except ImportError:
+    class ChoiceType(object):
+        pass
 
+from ...core.classtypes.enum import Enum
 from ...core.types.scalars import ID, Boolean, Float, Int, String
 from .fields import ConnectionOrListField, SQLAlchemyModelField
 
@@ -59,3 +65,9 @@ def convert_column_to_boolean(type, column):
 @convert_sqlalchemy_type.register(types.Numeric)
 def convert_column_to_float(type, column):
     return Float(description=column.doc)
+
+
+@convert_sqlalchemy_type.register(ChoiceType)
+def convert_column_to_enum(type, column):
+    name = '{}_{}'.format(column.table.name, column.name).upper()
+    return Enum(name, type.choices, description=column.doc)