apollo-server-express：如何解决内部订阅问题？

Posted 2023-03-10

【中文标题】apollo-server-express：如何解决内部订阅问题？

【英文标题】：apollo-server-express: how to resolve inside subscriptions?

【发布时间】：2018-06-17 22:24:12

【问题描述】：

在执行常规 graphQL 查询时，我可以轻松获取嵌套对象或计算。 但是当在订阅中时，例如：

subscription 
  Event(filter: 
    mutation_in: [CREATED]
  ) 
    node 
      title
      description
      start
      end
      seats
      bookings
      owner 
        email
      
    
  

我一添加bookings 或owner ... ，它就会中断。我在当时的服务器上没有看到错误消息。 QraphiQL 仅显示 [object Object] 作为响应。

有趣的模式是：

type Event 
  id: ID!
  title: String!
  description: String!
  owner: User!
  seats: Int
  bookings: Int
  start: DateTime!
  end: DateTime!
  tickets: [EventTicket!]!



type Mutation 
  createEvent(event: EventInput!): Event

input EventInput 
  title: String!
  description: String!
  seats: Int
  start: DateTime!
  end: DateTime!



type Subscription 
  Event(filter: EventSubscriptionFilter): EventSubscriptionPayload

input EventSubscriptionFilter 
  mutation_in: [_ModelMutationType!]

type EventSubscriptionPayload 
  mutation: _ModelMutationType!
  node: Event

enum _ModelMutationType 
  CREATED
  UPDATED
  DELETED

以及解析器：

import  ObjectId  from "mongodb"
import pubsub from "../../utils/pubsub"

export default 
  // ...
  Mutation: 
    createEvent: async (_, data,  mongo:  Events , user ) => 
      const newEvent = data.event
      newEvent.ownerId = user._id
      const response = await Events.insert(newEvent)
      const [_id] = response.insertedIds
      newEvent._id = _id
      pubsub.publish("Event",  Event:  mutation: "CREATED", node: newEvent  )
      return newEvent
    ,
  ,
  Subscription: 
    Event: 
      subscribe: () => pubsub.asyncIterator("Event"),
    ,
  ,
  Event: 
    id: event => event._id.toString(),
    owner: async (event, _,  mongo:  Users  ) => Users.findOne( _id: event.ownerId ),
    bookings: async (event, _,  mongo:  EventTickets  ) =>
      EventTickets.find( eventId: event._id ).count(),
    tickets: async (event, _,  mongo:  EventTickets  ) =>
      EventTickets.find( eventId: event._id ).toArray(),
  ,

关于如何处理这个问题的任何想法（和/或如何获得正确的错误消息以进行调试^^）。

【参考方案1】：

搜索后确定，I found the solution/hack here。

    SubscriptionServer.create(
        
           execute, subscribe, schema,
           onOperation: (message, params, webSocket) => 
            return  ...params, context: mongo 
          ,
        ,
         server, path: '/subscriptions' ,
    );

谢谢nharraud。