prisma2 订阅返回数据：null

Posted 2023-03-10

【中文标题】prisma2 订阅返回数据：null

【英文标题】：prisma2 subscriptions returns data: null

【发布时间】：2020-01-03 00:21:22

【问题描述】：

我有一个基本的 pubsub 使用样板和 graphql-yoga 在这里工作： https://github.com/ryanking1809/prisma2_subscriptions https://codesandbox.io/s/github/ryanking1809/prisma2_subscriptions/tree/sql-lite

带有发布突变：

const Mutation = objectType(
  name: 'Mutation',
  definition(t) 
   //...
    t.field('publish', 
      type: 'Post',
      nullable: true,
      args: 
        id: idArg(),
      ,
      resolve: async (parent,  id , ctx) => 
        const post = await ctx.photon.posts.update(
          where:  id ,
          data:  published: true ,
          include:  author: true 
        );
        ctx.pubsub.publish("PUBLISHED_POST", 
          publishedPost: post
        );
        return post
      ,
    )
  ,
)

还有一个订阅 - 我只是返回 true 以确保 withFilter（来自 graphql-yoga）正常工作。

const Subscription = objectType(
    name: "Subscription",
    definition(t) 
        t.field("publishedPostWithEmail", 
            type: "Post",
            args: 
                authorEmail: stringArg( required: false )
            ,
            subscribe: withFilter(
                (parent,  authorEmail , ctx) => ctx.pubsub.asyncIterator("PUBLISHED_POST"),
                (payload,  authorEmail ) => true
            )
        );
    
);

在publish 上返回以下内容（您可以将这些内容复制并粘贴到代码沙箱中 - 这很整洁！）

mutation 
  publish(
    id: "cjzwz39og0000nss9b3gbzb7v"
  ) 
    id,
    title,
    author 
      email
    
  

subscription 
  publishedPostWithEmail(authorEmail:"[e-mail]") 
    title,
    content,
    published
  

  "errors": [
    
      "message": "Cannot return null for non-nullable field Subscription.publishedPostWithEmail.",
      "locations": [
        
          "line": 2,
          "column": 3
        
      ],
      "path": [
        "publishedPostWithEmail"
      ]
    
  ],
  "data": null

由于某种原因，它返回了data: null。当我在过滤器函数中记录payload.publishedPosts 时，似乎一切都在那里。

 id: 'cjzwqcf2x0001q6s97m4yzqpi',
  createdAt: '2019-08-29T13:34:26.648Z',
  updatedAt: '2019-08-29T13:54:19.479Z',
  published: true,
  title: 'Check Author',
  content: 'Do you save the author?',
  author:
    id: 'sdfsdfsdfsdf',
     email: '[e-mail]',
     name: 'Prisma Sub'  

我有什么遗漏吗？

【参考方案1】：

终于明白了！ ?

订阅函数需要以pubsub中的key命名。 因此，如果您有如下发布功能：

ctx.pubsub.publish("PUBLISHED_POST", 
          publishedPost: post
        );

那么你必须将你的订阅命名为publishedPost

        t.field("publishedPost", 
            type: "Post",
            args: 
                authorEmail: stringArg( required: false )
            ,
            subscribe: withFilter(
                (parent,  authorEmail , ctx) =>
                    ctx.pubsub.asyncIterator("PUBLISHED_POST"),
                (payload,  authorEmail ) => payload.publishedPost.author.email === authorEmail
            )
        );

如果您将订阅命名为 publishedPostWithEmail，则不会返回任何数据

        t.field("publishedPostWithEmail", 
                //...
        );

---

有趣的是，如果你有 2 把钥匙

ctx.pubsub.publish("PUBLISHED_POST", 
          publishedPost2: post,
          publishedPost3: post
        );

如果您将订阅命名为 publishedPost2，那么结果中将省略 publishedPost3。

---

奇怪的是，如果您订阅了 2 条消息，您将获得所有数据

ctx.pubsub.publish("PUBLISHED_POST", 
          publishedPost: post,
          publishedPost2: post
        );
        ctx.pubsub.publish("PUBLISHED_POST_X", 
          publishedPostX: post,
          publishedPostY: post
        );

ctx.pubsub.asyncIterator([
                        "PUBLISHED_POST",
                        "PUBLISHED_POST_X"
                    ]),

返回publishedPost、publishedPost2、publishedPostX、publishedPostY

因此，您可以通过订阅具有单个项目的数组来解决上述问题，并且订阅的名称变得无关紧要。

        t.field("publishedPostXYZ", 
            type: "Post",
            args: 
                authorEmail: stringArg( required: false )
            ,
            subscribe: withFilter(
                (parent,  authorEmail , ctx) =>
                    ctx.pubsub.asyncIterator([
                        "PUBLISHED_POST"
                    ]),
                (payload,  authorEmail ) => 
                    return payload.publishedPost.author.email === authorEmail;
                
            )
        );

---

看来这可能是一个错误?