如何在角度5的一定时间后防止websocket关闭？

Question

我使用'rxjs-websockets'来连接websockets.但在一定时间(约2分钟)后,连接关闭.在手动关闭之前,如何保持连接.

这是我使用的代码片段

constructor(private socketService: WebSocketService) {}

this.socketService.connect('/endpoint');
this.socketSubscription = this.socketService.messages
      .subscribe(result => {            
            // perform operation
    });

这是WebSocketService

import {Injectable} from '@angular/core';
import {QueueingSubject} from 'queueing-subject';
import {Observable} from 'rxjs/Observable';
import websocketConnect from 'rxjs-websockets';
import 'rxjs/add/operator/share';
import 'rxjs/add/operator/retryWhen';
import 'rxjs/add/operator/delay';

@Injectable()
export class WebSocketService {
  private inputStream: QueueingSubject<string>;
  public messages: Observable<string>;

  constructor() {    
  }

  public connect(socketUrl) {
      this.messages = websocketConnect(
        socketUrl,
        this.inputStream = new QueueingSubject<string>()
      ).messages.retryWhen(errors => errors.delay(1000))
        .map(message => JSON.parse(message))
        .share();
  }

  public send(message: string): void {
    this.inputStream.next(message);
  }
}

Answer 1

Websockets通常在一些消息交换的帮助下长时间保持连接.在我们的例子中,我们可以将其称为'ping => pong',客户端发送消息'ping',服务器可以响应消息'pong'.

您可以按如下方式每30秒发送一次ping.

setInterval(() => {
    this.socketService.send('ping');
}, 30000);

当您将在WebSocketService接收的每条消息转换为JSON时,您必须进行这些更改以获得JSON解析错误.

export class WebSocketService {
.
.
.

    public connect(socketUrl) {
      this.messages = websocketConnect(
        socketUrl,
        this.inputStream = new QueueingSubject<string>()
      ).messages.retryWhen(errors => errors.delay(1000))
        //parse messages except pong to avoid JSON parsing error
        .map(message => message === 'pong' ? message : JSON.parse(message))
        .share();
    }
.
.
.
}