Returning a list of enums with string values with Graphene

Question

This is using Python and the Graphene library.

I want to provide a list of constants to my front-end via GraphQL. I went down the route of using inspection, but it will only output the keys of the enum. Not the values. I learned that Graphene enums only contain name/description.

    {
      __type(name: "FruitEnum") {
        enumValues {
          name
          description
        }
      }
    }

this returns

{
  "data": {
    "__type": {
      "enumValues": [
        {
          "name": "APPLE",
          "description": null
        },
        {
          "name": "BANANA",
          "description": null
        },
        {
          "name": "ORANGE",
          "description": null
        }
      ]
    }
  },
  "errors": null
}

This is what the actual enum looks like

class FruitEnum(Enum):
    APPLE = "Apple -- but could also be other information for the front end"
    BANANA = "Banana"
    ORANGE = "Orange"

Is there a preferred way of exposing a list of constants like this through GraphQL? Can introspection be modified with a resolver to read the value? I am taking a regular Python enum and registering it with Graphene using the Enum.from_enum function.

Answer 1

I don't think you add or remove fields from the enumValues since it is the standard.

But, you can add the description by specifying a description property in the enum class.

import graphene

from enum import Enum as PyEnum


class FruitEnum(PyEnum):
    APPLE = "Apple"
    BANANA = "Banana"
    ORANGE = "Orange"

    def get_field_description(self):
        mapper = {
            "default": "default description",
            "APPLE": "Apple description"
        }
        return mapper.get(self.name, mapper['default'])

    @property
    def description(self):
        return self.get_field_description()


class FruitType(graphene.ObjectType):
    foo = graphene.Enum.from_enum(FruitEnum)()

Thus you will get a response as,

{
  "data": {
    "__type": {
      "name": "FruitEnum",
      "enumValues": [
        {
          "name": "APPLE",
          "description": "Apple description"
        },
        {
          "name": "BANANA",
          "description": "default description"
        },
        {
          "name": "ORANGE",
          "description": "default description"
        }
      ]
    }
  }
}

Answer 2

Using Django you can simply write:

from django.db import models

from django.utils.translation import gettext_lazy as _   # Provides a convenient way to translate your descriptions

class FruitEnum(models.TextChoices):
    APPLE = "Apple", _('Apple description goes here')
    BANANA = "Banana", _('Banana description goes here')
    ORANGE = "Orange", _('Orange description goes here')

Thus you will get a response as,

{
  "data": {
    "__type": {
      "name": "FruitEnum",
      "enumValues": [
        {
          "name": "APPLE",
          "description": "Apple description goes here"
        },
        {
          "name": "BANANA",
          "description": "Banana description goes here"
        },
        {
          "name": "ORANGE",
          "description": "Orange description goes here"
        }
      ]
    }
  }
}