重新连接Angular和rxjs中的websocket? [英] Reconnecting a websocket in Angular and rxjs?

问题描述

我有一个基于ngrx/store(v2.2.2)和rxjs(v5.1.0)的应用程序，该应用程序使用可观察的方法侦听Web套接字中的传入数据.当我启动应用程序时，我会完美地接收到传入的数据.

但是过了一会儿(更新很少出现)，连接似乎丢失了，我再也没有收到传入的数据了.我的代码:

服务

import { Injectable, OnInit } from '@angular/core';
import { Observable } from 'rxjs';

@Injectable()
export class MemberService implements OnInit {

  private websocket: any;
  private destination: string = "wss://notessensei.mybluemix.net/ws/time";

  constructor() { }

  ngOnInit() { }

  listenToTheSocket(): Observable<any> {

    this.websocket = new WebSocket(this.destination);

    this.websocket.onopen = () => {
      console.log("WebService Connected to " + this.destination);
    }

    return Observable.create(observer => {
      this.websocket.onmessage = (evt) => {
        observer.next(evt);
      };
    })
      .map(res => res.data)
      .share();
  }
}

订户

  export class AppComponent implements OnInit {

  constructor(/*private store: Store<fromRoot.State>,*/ private memberService: MemberService) {}

  ngOnInit() {
    this.memberService.listenToTheSocket().subscribe((result: any) => {
      try {
        console.log(result);
        // const member: any = JSON.parse(result);
        // this.store.dispatch(new MemberActions.AddMember(member));
      } catch (ex) {
        console.log(JSON.stringify(ex));
      }
    })
  }
}

当Web套接字超时时，我该怎么做才能重新连接，以便可观察对象继续发出输入值?

我在此处，此处，但似乎并没有解决这个问题(以我能理解的方式).

注意:位于wss://notessensei.mybluemix.net/ws/time的websocket处于活动状态，并且每分钟发出一次时间戳(以防万一要对其进行测试).

非常感谢您的建议！

解决方案

实际上，rxjs中现在有一个WebsocketSubject！

 import { webSocket } from 'rxjs/webSocket' // for RxJS 6, for v5 use Observable.webSocket

 let subject = webSocket('ws://localhost:8081');
 subject.subscribe(
    (msg) => console.log('message received: ' + msg),
    (err) => console.log(err),
    () => console.log('complete')
  );
 subject.next(JSON.stringify({ op: 'hello' }));

当您重新订阅断开的连接时，它会处理重新连接.因此，例如，将其编写为重新连接:

subject.retry().subscribe(...)

有关更多信息，请参阅文档.不幸的是，搜索框未显示该方法，但您可以在此处找到它:

http://reactivex.io/rxjs/class/es6/Observable.js〜Observable.html#static-method-webSocket

#导航在我的浏览器中不起作用，因此请在该页面上搜索"webSocket".

来源: http://reactivex.io/rxjs/file/es6/observable/dom/WebSocketSubject.js.html#lineNumber15

I have a ngrx/store (v2.2.2) and rxjs (v5.1.0) based application that listens to a web socket for incoming data using an observable. When I start the application I receive incoming data flawlessly.

However after a while (updates are coming in quite infrequently) the connection seem to get lost and I don't get anymore incoming data. My code:

The service

import { Injectable, OnInit } from '@angular/core';
import { Observable } from 'rxjs';

@Injectable()
export class MemberService implements OnInit {

  private websocket: any;
  private destination: string = "wss://notessensei.mybluemix.net/ws/time";

  constructor() { }

  ngOnInit() { }

  listenToTheSocket(): Observable<any> {

    this.websocket = new WebSocket(this.destination);

    this.websocket.onopen = () => {
      console.log("WebService Connected to " + this.destination);
    }

    return Observable.create(observer => {
      this.websocket.onmessage = (evt) => {
        observer.next(evt);
      };
    })
      .map(res => res.data)
      .share();
  }
}

The subscriber

  export class AppComponent implements OnInit {

  constructor(/*private store: Store<fromRoot.State>,*/ private memberService: MemberService) {}

  ngOnInit() {
    this.memberService.listenToTheSocket().subscribe((result: any) => {
      try {
        console.log(result);
        // const member: any = JSON.parse(result);
        // this.store.dispatch(new MemberActions.AddMember(member));
      } catch (ex) {
        console.log(JSON.stringify(ex));
      }
    })
  }
}

What do I need to do to reconnect the web socket when it times out, so the observable continues to emit incoming values?

I had a look at some Q&A here, here and here and it didn't seem to address this question (in a way I could comprehend).

Note: the websocket at wss://notessensei.mybluemix.net/ws/time is live and emits a time stamp once a minute (in case one wants to test that).

Advice is greatly appreciated!

解决方案

Actually there now is a WebsocketSubject in rxjs!

 import { webSocket } from 'rxjs/webSocket' // for RxJS 6, for v5 use Observable.webSocket

 let subject = webSocket('ws://localhost:8081');
 subject.subscribe(
    (msg) => console.log('message received: ' + msg),
    (err) => console.log(err),
    () => console.log('complete')
  );
 subject.next(JSON.stringify({ op: 'hello' }));

It does handle reconnection when you resubscribe to a broken connection. So for example write this to reconnect:

subject.retry().subscribe(...)

See the docs for more info. Unfortunately the searchbox doesn't show the method, but you find it here:

http://reactivex.io/rxjs/class/es6/Observable.js~Observable.html#static-method-webSocket

that #-navigation is not working in my browser, so search for "webSocket" on that page.

Source: http://reactivex.io/rxjs/file/es6/observable/dom/WebSocketSubject.js.html#lineNumber15

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