带有多个forkjoin的rxjs在执行HTTP请求时 [英] rxjs with multiple forkjoin when doing http requests

问题描述

我正在执行一些http请求，并使用rxjs成功通知结果:

I am doing some http requests and use rxjs for successfull notification of the result:

  getReportings(departmentId: number): Observable<any> {
        return Observable.forkJoin(
            this.http.get('/api/members/' + departmentId).map(res => res.json()),
            this.http.get('/api/reports/' + departmentId).map(res => res.json())
        );
    }

当两个HTTP请求都完成后，我希望在getReportings方法内迭代reports数组，读取一些值，并为每个报告再次使用这些值进行新的http请求.

When both http requests are done I want inside the getReportings method to iterate the reports array , read some values and for each report make again a new http request with those values.

总共我有2个(成员/报告)+ appr. 4到8个(其他内容)请求.

All in all I have 2 (member/reports) + appr. 4 to 8 (other stuff) requests.

全部通过时.完成6到8个请求后，我想在成功处理程序中获取前6到8个请求中的所有数据.

When all appr. 6 to 8 requests are done I want to get ALL data from the previous 6 to 8 requests in the successfull handler.

如何使用rxjs做到这一点?

How can I do this with rxjs?

更新

随着olsn用户要求提供更多详细信息，现在我了解他的关注点，我在这里放置了更多数据(伪代码)，6至8个请求应如何显示:

As user olsn asked for more details and I understand him now whats his concern I put more data here (pseudo code) how the 6 to 8 requests should look like:

getReportings(departmentId: number): Observable<any> {
    return Observable.forkJoin(
        this.http.get('/api/members/' + departmentId).map(res => res.json()),
        this.http.get('/api/reports/' + departmentId).map(res => res.json())
    ).switchMap((result: [any[], any[]]) => {
        let members: any[] = result[0];
        let reports: any[] = result[1];
        let allNewStreams: Observable<any>[] = [
            Observable.of(members),
            Observable.of(reports)
        ]; 

        for(let report of reports)
        {
            allNewStreams.push(
this.http.get(report.url + ?key1=report.name1?).map(res => res.json()));
        }


        return Observable.forkJoin(allNewStreams); // will contain members, reports + 4-6 other results in an array [members[], reports[], ...other stuff]
    });
}

推荐答案

您可以使用switchMap扩展流，如下所示:

You could extend your stream using switchMap, like this:

getReportings(departmentId: number): Observable<any> {
    return Observable.forkJoin(
        this.http.get('/api/members/' + departmentId).map(res => res.json()),
        this.http.get('/api/reports/' + departmentId).map(res => res.json())
    ).switchMap((result: [any[], any[]]) => {
        let members: any[] = result[0];
        let reports: any[] = result[1];
        let allNewStreams: Observable<any>[] = [
            Observable.of(members),
            Observable.of(reports)
        ];
        // do your stuff and push new streams to array...
        if (foo) { // for each additional request
            let reportId: string | number = reports[0].id; // or however you retrieve the reportId
            allNewStreams.push(
                this.http.get('some/api/ + bar)
                    .map(res => res.json())
                    .map(data => ({reportId, data})); // so your final object will look like this: {reportId: "d38f68989af87d987f8", data: {...}}
            );
        }

        return Observable.forkJoin(allNewStreams); // will contain members, reports + 4-6 other results in an array [members[], reports[], ...other stuff]
    });
}

这应该做到，它更像是一种旧式逻辑锤" 方法-如果您正在寻找它:可能有一种更优雅的方法来解决此问题其他运算符，但是如果不知道全部数据和所有逻辑就很难说.

This should do it, it's more like an "old-style-logic-hammer" approach - in case you are looking for it: There might be a more elegant way to solve this by using other operators, but that is hard to say without knowing the full data and all logic.

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