CODEWITHSUNDEEP
angularwebsocketspring-websocket
Jane Wayne
Jane Wayne

Reputation: 8855

Why is the web socket is closed in my Angular 2 application although I did not explicitly close it yet?

I am using the angular2-websocket wrapper. Although I have not closed the websocket, when I attempt to send a message later, I get an error saying that the websocket has already been closed.

My component looks like the following.

export class ListDataComponent implements OnInit, OnDestroy, AfterViewInit {
 ws: $WebSocket;
 sub: Subscription;

 ngAfterViewInit() { this.initWebSocket(); }
 ngOnDestroy() { this.destroyWebSocket(); }
 initWebSocket(): void {
   this.ws = new $WebSocket('ws://localhost:8080/topic/data');
   this.sub = this.ws.getDataStream().subscribe(
    data => {
     console.log(data);
     //this part is following the example on the github page
     //makes me unsure because the close method will force a close and true/false only signifies if the closing is immediate or not
     //even if i comment out this line, i still get the same behavior
     this.ws.close(false);
    },
    err => console.err(data)
   );
 }
 destroyWebSocket(): void {
   //this is the only place where i destroy/release my websocket resources
   if (this.sub) {
    try { 
      this.sub.unsubscribe(); 
    } catch(err) { }
   }
   if (this.ws) {
    try { 
     this.ws.close(true); 
    } catch(err) { }
   }
 }
 //this method is bound to a bunch of checkboxes that triggers sending data back to the websocket topic
 selectionChanged(i: number): void {
   let json = getSomeJson(i); //gets some JSON to send back; omitted
   this.ws.send(json).subscribe(
    data => console.log(data),
    err => {
     //it seems i can't send because the websocket has been closed! why?
     console.error(err);
    }
   );
 }
}

Looking at the JavaScript console, I see the following message.

Socket connection has been closed
(anonymous) @   list-data-ws.component.ts:141
SafeSubscriber.__tryOrSetError  @   Subscriber.js:243
SafeSubscriber.error    @   Subscriber.js:199
Subscriber._error   @   Subscriber.js:128
Subscriber.error    @   Subscriber.js:102
(anonymous) @   angular2-websocket.js:123
Observable._trySubscribe    @   Observable.js:57
Observable.subscribe    @   Observable.js:45
webpackJsonp.362.ListTransactionWsComponent.cryptoSelected  @   list-transaction-ws.component.ts:139
View_ListTransactionWsComponent1.handleEvent_2  @   /AppModule/ListTransactionWsComponent/component.ngfactory.js:68
(anonymous) @   view.js:664
(anonymous) @   dom_renderer.js:489
webpackJsonp.946.ZoneDelegate.invokeTask    @   zone.js:363
onInvokeTask    @   ng_zone.js:264
webpackJsonp.946.ZoneDelegate.invokeTask    @   zone.js:362
webpackJsonp.946.Zone.runTask   @   zone.js:166
ZoneTask.invoke

What's weird is that I still keep getting data coming back in the data stream. I have also placed debugging messages on the backend (Spring Boot) and I don't see that the websocket has been closed.

If it helps,

Upvotes: 0

Views: 875

Answers (1)

Jane Wayne
Jane Wayne

Reputation: 8855

I was using 0.9.0 of angular2-websocket. After upgrading to 0.9.1, everything works as expected. Hope this information helps anyone else out there: DO NOT USE v0.9.0.

Upvotes: 1

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