GraphQL 在 Django 中的一个请求中进行多个查询

Posted 2023-03-08

【中文标题】GraphQL 在 Django 中的一个请求中进行多个查询

【英文标题】：GraphQL multiple queries in one request in Django

【发布时间】：2020-07-08 11:48:56

【问题描述】：

我使用 Django 和石墨烯来构建 API，但我想在一个查询中组合两个模型，模型的所有字段都是相同的。

示例 架构.py

import graphene
from graphene_django import DjangoObjectType
from .models import Post, Post2

class PostType(DjangoObjectType):
    class Meta:
        model = Post

class Post2Type(DjangoObjectType):
    class Meta:
        model = Post2

class Query(graphene.ObjectType):
    post = graphene.List(PostType)
    post2 = graphene.List(Post2Type)

    def resolve_post(self, info):
        return Post.objects.all()

    def resolve_post2(self, info):
        return Post2.objects.all()

我收到此回复：

  "data": 
    "post": [
      
        "title": "post 1"
      
    ],
    "post2": [
      
        "title": "post test"
      
    ]
  

我想得到的是：

  "data": 
    "allPost": [
      
        "title": "post 1"
      ,
      
        "title": "post test"
      
  

【参考方案1】：

您可以创建一个联合类型 (https://docs.graphene-python.org/en/latest/types/unions/#unions) 的列表，它应该可以满足您的需求：

class PostUnion(graphene.Union):
    class Meta:
        types = (PostType, Post2Type)

    @classmethod
    def resolve_type(cls, instance, info):
        # This function tells Graphene what Graphene type the instance is
        if isinstance(instance, Post):
            return PostType
        if isinstance(instance, Post2):
            return Post2Type
        return PostUnion.resolve_type(instance, info)


class Query(graphene.ObjectType):
    all_posts = graphene.List(PostUnion)

    def resolve_all_posts(self, info):
        return list(Post.objects.all()) + list(Post2.objects.all())