扩展 graphene/graphene_django 中的查询参数

Question

如何向石墨烯中的 GraphQL 查询添加非字段参数？这是一个用例的示例。我希望能够做到：

{
  hsv(h: 40, s: 128, v: 54) {
    r
    g
    b
    name
}

使用这个 Django 模型：

from django.db import models
from django.core.validators import MinValueValidator, MaxValueValidator,

class Color(models.Model):
    name = models.CharField(
        "name",
        max_length=24,
        null=False, blank=False)
    r = models.IntegerField(
        "red", null=False, blank=False,
        validators=[MinValueValidator(0), MinValueValidator(255)]
    )

    g = models.IntegerField(
        "green", null=False, blank=False,
        validators=[MinValueValidator(0), MinValueValidator(255)]
    )

    b = models.IntegerField(
        "blue", null=False, blank=False,
        validators=[MinValueValidator(0), MinValueValidator(255)]
    )

以及这个 GraphQL 对象类型和基于它的查询：

from graphene import ObjectType, IntegerField, Field, relay
from graphene_django import DjangoObjectType

from .django import Color
from colorsys import hsv_to_rgb

class ColorNode(DjangoObjectType):
    r = IntegerField()
    g = IntegerField()
    b = IntegerField()

    class Meta:
        model = Color

class Query(ObjectType):
    rgb = relay.node.Field(ColorNode)
    hsv = relay.node.Field(ColorNode)
    named = relay.node.Field(ColorNode)

    def resolve_rgb(self, args, context, info):
        if not all(map(lambda x: x in args, ['r', 'g', 'b'])):
            # Arguments missing
            return None
        return Color.objects.get(**args)

    def resolve_hsv(self, args, context, info):
        if not all(map(lambda x: x in args, ['h', 's', 'v'])):
            # Arguments missing
            return None

        r, g, b = hsv_to_rgb(args['h'], args['s'], args['v'])
        return Color.objects.get(r=r, g=g, b=b)

    def resolve_named(self, args, context, info):
        if not 'name' in args:
            # Arguments missing
            return None
        return Color.objects.get(name=args['name'])

它失败了，因为参数不被接受。我缺少什么？

Answer 1

答案其实很简单。要将参数添加到解析器，请在字段的构造函数中声明参数，如下所示：

rgb = relay.node.Field(ColorNode,
    r=graphene.String(),
    g=graphene.String(),
    b=graphene.String())
hsv = relay.node.Field(ColorNode,
    h=graphene.String(),
    s=graphene.String(),
    v=graphene.String()))
named = relay.node.Field(ColorNode,
    name=graphene.String())

然后，参数可以包含在查询中，如上所示。