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:
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();
}
}
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!
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