在 Angular 2 中的多个组件之间共享 WebSocket 数据的最佳方式是什么? [英] The best way to share WebSocket data between multiple components in Angular 2?

问题描述

我开始构建一个应用程序.有很多组件.他们每个人都需要来自 1 个 webSocket 的一部分数据.webSocket接收对象示例:

I start to build an application. There are a lot of components. Each of them need a part of data from 1 webSocket. The example of a receiveing object by webSocket:

每个 Angular 2 组件需​​要 1 个来自接收对象的字段.是否可以创建 1 项服务，该服务将连接到 webSocket、接收数据并在所有组件之间共享?我认为这将是一个很好的解决方案.

Each Angular 2 component need 1 field from receiveing object. Is it possible to make 1 service, that will connect to webSocket, receive data and share it between all components ? I think it will be a good solution.

现在我正在使用下一种方法:

Now i'm using the next approach:

getConfigCallback() {
    this.connectionSockets.telemetry = io(this.config.connections.telemetry);
    this.connectionSockets.controlFlow = new WebSocket(this.config.connections.controlFlow.server + ':' + this.config.connections.controlFlow.port);

    this.connectionSockets.telemetry.on('telemetry', function(data) {
        console.log(data);
    });

    this.connectionSockets.controlFlow.onopen = function(data) {
        console.log('onOpen', data);
    };

    this.connectionSockets.controlFlow.onmessage = function(data) {
        console.log('onMessage', data);
    };
}

我在主组件中接收数据，并希望使用组件的实例在组件之间共享它.但我认为这是一个坏主意，并且存在更好的解决方案.

I receive data in a main component and want to share it between components using component's instances. But i think it's a bad idea and there is exist a better solution.

推荐答案

当然你可以通过在启动应用程序时设置它的提供者来共享你的服务:

Sure you can share your service by set its provider when bootstrapping the application:

bootstrap(AppComponent, [ WebSocketService ]);

这样，您将在整个应用程序中共享同一个服务实例.我的意思是当您注入 WebSocketService 服务时，无论组件/服务如何，相应的实例都是相同的.

This way you will share the same instance of your service in the whole application. I mean when you inject the WebSocketService service, the corresponding instance will be the same whatever the component / service.

为了能够共享接收到的数据，我会利用一个 hot observable.默认情况下，可观察对象是冷的，因此您需要使用 share 运算符.

To be able to share the received data, I would leverage an hot observable. By default observables are cold so you need to use the share operator.

initializeWebSocket(url) {
  this.wsObservable = Observable.create((observer) => {
    this.ws = new WebSocket(url);

    this.ws.onopen = (e) => {
      (...)
    };

    this.ws.onclose = (e) => {
      if (e.wasClean) {
        observer.complete();
      } else {
        observer.error(e);
      }
    };

    this.ws.onerror = (e) => {
      observer.error(e);
    }

    this.ws.onmessage = (e) => {
      observer.next(JSON.parse(e.data));
    }

    return () => {
      this.ws.close();
    };
  }).share();
}

想要从 web socket 接收数据的组件可以这样使用这个 observable:

Components that would like to receive data from the web socket could use this observable this way:

@Component({
  (...)
})
export class SomeComponent {
  constructor(private service:WebSocketService) {
    this.service.wsObservable.subscribe((data) => {
      // use data
    });
  }
}

有关基于事件的方法"部分的更多详细信息，请参阅本文:

See this article for more details in the "event-based approach" section:

• https://jaxenter.com/reactive-programming-http-and-angular-2-124560.html

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