Apollo GraphQL订阅

Question

我在Apollo中的GraphQL订阅遇到了麻烦。我想订阅关于主题的添加“透视图”（基本上是在帖子上添加评论），我很确定我已经正确地设置了服务器。客户才是给我带来麻烦的人。（如果这个问题看起来很熟悉，我以前问过它，以为我得到了答案，但没有去）。下面是我的订阅模式：

type Subscription {
  perspectiveAdded: Perspective
}

schema {
  query: RootQuery
  mutation: Mutation
  subscription: Subscription
}

Subscription: {
    perspectiveAdded(perspective) {
      return perspective;
    }
  }

const pubsub = new PubSub();
const subscriptionManager = new SubscriptionManager({
  schema,
  pubsub,
  setupFunctions: {
    perspectiveAdded: (options, args) => {
      perspectiveAdded: {
        filter: (topic) => {
          return topic
        }
      }
    },
  }
});

export { subscriptionManager, pubsub };

//...    
return perspective.save((error, perspective) => {
   if(error){
     console.log(error);
   }

   //Publish it to Subscription channel
   pubsub.publish('perspectiveAdded', perspective);
});

const PORT = process.env.PORT || 4000;
const server = createServer(app);

server.listen(PORT, ()=>{
    new SubscriptionServer(
    {
        subscriptionManager: subscriptionManager,
        onConnect: (connectionParams, webSocket) => {
        console.log('Websocket connection established Lord Commander');
    },
    onSubscribe: (message, params, webSocket) => {
        console.log("The client has been subscribed, Lord Commander", message, params);
    },
    onUnsubsribe: (webSocket) => {
        console.log("Now unsubscribed, Lord Commander");
    },
    onDisconnect: (webSocket) => {
        console.log('Now disconnected, Lord Commander');
    }
    },
    {
        server: server,
        path: '/subscriptions',
    });
    console.log('Server is hot my Lord Commander!');
});

我也正确地连接了客户端，因为在我的终端中，我看到了“WebSocket connection Selected”消息。我被难倒的部分是如何实际调用订阅。根据Apollo的博客，我应该能够在GraphiQL中测试订阅（因为我使用的是Apollo服务器，现在是graphql-server-express)，但是它说“resolve function for\”subscription.perspectiveadded\“return undefined”。

对于我的组件，我尝试连接“subscribe tomore”，但在浏览器控制台中，我得到了一个错误对象，该对象表示“从onsubscribe返回的params无效！返回值必须是一个对象！”我不确定它指的是哪个对象。

下面是我的订阅查询PerspectiveSubscription：

export default gql`
subscription {
  perspectiveAdded {
    id
    content
  }
}
`;

constructor(props){
      super(props);
      this.state = {};
      this.subscription = null;
    }



    componentWillReceiveProps(nextProps) {
      if (!this.subscription && !nextProps.data.loading) {
        let { subscribeToMore } = this.props.data
        this.subscription = subscribeToMore(
          {
            document: perspectiveSubscription,
            updateQuery: (previousResult, { subscriptionData }) => {
              if(!subscriptionData.data){
                console.log('no new subscription data');
                return previousResult;
              }

              const newPerspective = subscriptionData.data.perspectiveAdded;
              console.log(newPerspective);
              return Object.assign({}, previousResult, newPerspective);
            }
          }
        )
      }

从这里，我在我的终端中得到一条消息，说客户端已经被订阅，但我仍然得到上面提到的错误对象。几天来我一直在为这件事烦恼--你们看到我错过了什么吗？具体地说，在客户端有什么想法吗？谢谢大家！

Answer 1

服务器端似乎不正确，因为添加了订阅，而graphiql也没有提供正确的结果。

我建议您检查频道定义：

js prettyprint-override">const pubsub = new PubSub();
const subscriptionManager = new SubscriptionManager({
  schema,
  pubsub,
  setupFunctions: {
    perspectiveAdded: (options, args) => {
      perspectiveAdded: {
        filter: (perspective) => {
        console.log(perspective); // check if object is correct
          return true; // return true and not the object as long as you do not want to filter
        }
      }
    },
  }
});

export { subscriptionManager, pubsub };