Ionic2中有多个$ http请求 [英] Multiple $http requests in Ionic2

问题描述

我想知道多个请求：

如果我的 $ http请求1 开始，让我们说 $ http request 1 结束并尝试拨打 $ http request 2 。 我的问题如何创建多个请求？

if my $http request 1 start , let's say $http request 1 ends and tried to call $http request 2. my question how can i create a multiple request ?

例如：call $ http request 1 然后 $ http请求2 。

for example : call $http request 1 then $http request 2.

推荐答案

据我所知，您尝试生成多个http请求，然后在所有请求结束时处理响应。例如，您可能需要从多个源加载数据，并延迟后加载逻辑，直到所有数据都已加载。

As I understand, you're trying to make more than one http request and then process the response when all those request have ended. For instance, you may need to load data from more than one source, and delay the post-loading logic until all the data has loaded.

如果是这种情况，可以使用ReactiveX Observables，因为它提供了一个名为 forkJoin（）的方法来包装多个Observables。

If that's the case, you could use ReactiveX Observables because it provides a method called forkJoin() to wrap multiple Observables.

import {Injectable} from '@angular/core';
import {Http, Response} from '@angular/http';
import {Observable} from 'rxjs/Rx';

@Injectable()
export class MultipleHttpService {

  constructor(private http:Http) { }

  // If any single request fails, the entire operation will result in an error state.
  getData0AndData1() {
    return Observable.forkJoin(
      this.http.get('/app/data0.json').map((res:Response) => res.json()),
      this.http.get('/app/data1.json').map((res:Response) => res.json())
    );
  }

}

然后你就可以获得所有数据通过订阅该observable：

Then you could get all the data by subscribing to that observable:

// Code in your page ...
this.myMultipleHttpService.getData0AndData1()
    .subscribe(
      data => {
        this.data0= data[0]
        this.data1 = data[1]
      },
      err => console.error(err)
    );

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