Question

使用RxJs和WebSockets我创建了一些应该从服务器接收数据的服务，并将其发送给我程序中服务的订阅者。当我只有1个服务时，没有问题，但在创建第二个服务后，第一个服务不再收到响应。我该如何确定呢？

这是我的WebSocket服务：

import { Injectable } from '@angular/core';
import * as Rx from 'rxjs/Rx';

@Injectable()
export class WebSocketService {
private subject: Rx.Subject<MessageEvent>;

public connect(url): Rx.Subject<MessageEvent> {
    if (!this.subject) {
        this.subject = this.create(url);
    }
    return this.subject;
}

private create(url): Rx.Subject<MessageEvent> {
    let ws = new WebSocket(url);

    let observable = Rx.Observable.create(
        (obs: Rx.Observer<MessageEvent>) => {
            ws.onmessage = obs.next.bind(obs);
            ws.onerror = obs.error.bind(obs);
            ws.onclose = obs.complete.bind(obs);

            return ws.close.bind(ws);
        })

    let observer = {
        next: (data: Object) => {
            if (ws.readyState === WebSocket.OPEN) {
                ws.send(JSON.stringify(data));
            }
        }
    }

    return Rx.Subject.create(observer, observable);
}
}

这是我的倒计时服务：

import { Injectable } from '@angular/core';
import { Observable, Subject } from 'rxjs/Rx';
import {WebSocketService } from './websocket.service';

const AUCTION_URL = 'ws://localhost:9999';

export interface Countdown {
days: number,
hours: number,
minutes: number,
seconds: number
}

@Injectable()
export class CountdownService {
public countdowns: Subject<Countdown>;

constructor(wsService: WebSocketService) {
    this.countdowns = <Subject<Countdown>>wsService
        .connect(AUCTION_URL)
        .map((response: MessageEvent): Countdown => {
            let data = JSON.parse(response.data);
            return {
                days: data.days,
                hours: data.hours,
                minutes: data.minutes,
                seconds: data.seconds
            }
        });
}
}

其他服务的实现方式与倒计时服务相同，但与其他变量相同。

感谢任何帮助，谢谢。

Answer 1

该服务是否跨多个组件使用？我会检查该服务是否只被实例化一次。

您还可以通过将share操作符添加到observable create：

来确保

let observable = Rx.Observable.create(
        (obs: Rx.Observer<MessageEvent>) => {
            ws.onmessage = obs.next.bind(obs);
            ws.onerror = obs.error.bind(obs);
            ws.onclose = obs.complete.bind(obs);

            return ws.close.bind(ws);
        }).share()

只有一个订阅者从服务器接收响应

1 个答案: