通知组件时服务功能的角度完成 [英] Notify component when service function is complete in angular

问题描述

我写它做一个HTTP查询到后端服务：

I writing a service which do a http query to the backend:

getPlacesForUser(){
 this.http.get("http://localhost:8080/processPlaces")
  .map(res => res.text())
  .subscribe(
    data => this.result = data,
    err => this.logError(err),
    () => console.log('Places Request completed')
  )
}

现在我想更新的组件端，如果请求完成：

Now I want to update the components-side, if the request is completed:

processPlaces(){
 this._backendService.getPlacesForUser();
}

我怎么能组件和服务之间的沟通？

How can I communicate between the component and service?

此外，我寻找最好的做法。

Furthermore I searching for the best practice.

推荐答案

在事实上，你可以直接从 getPlacesForUser 方法返回observble并在其上附加一个订阅方法

In fact, you can return the observble directly from the getPlacesForUser method and attach a subscribe method on it.

• 服务

getPlacesForUser(){
  return this.http.get("http://localhost:8080/processPlaces")
    .map(res => res.text());
}

组件

processPlaces(){
 this._backendService.getPlacesForUser()
  .subscribe(
    data => this.result = data,
    err => this.logError(err),
    () => console.log('Places Request completed')
  );
}

的结果属性对应，您可以在组件中使用该组件的属性。

The result attribute corresponds to an attribute of the component you can use in the component.

您可以注意到一个异步管道可直接利用中前pressions观察到的（例如在一个 ngFor 之一）。

You can notice that a async pipe is available to directly leverage observable in expressions (for example within an ngFor one).

我觉得这个答案可以帮助你：<一href=\"http://stackoverflow.com/questions/34450131/how-to-consume-http-component-efficiently-in-angular-2-beta/34450948#34450948\">How在角2公测有效地消耗HTTP组件？。

I think that this answer could help you: How to Consume Http Component efficiently in angular 2 beta?.

希望它可以帮助你，
蒂埃里

Hope it helps you, Thierry

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