每秒Angular 4 http请求

Question

我试图每秒调用我的API。我不知道该怎么做。

准时来电是可以的：

loadRequest(payload: any): Observable<RequestTask[]> {
    const headers = new Headers({'Authorization': localStorage.getItem('authorizationToken')});
    const options = new RequestOptions({headers: headers});
    const requestId = payload;
    const url = '/api/requests/'+ requestId +'/events'

    return this.http
        .get(url, options)
        .map(response => {
            const requests = response.json();
            console.log("Request API", requests)
            return requests.map(request => {
                return new RequestTask(request)
            });
        })
        .catch(this.handleError);
}

我的每秒呼叫测试

loadRequest(payload: any): Observable<RequestTask[]> {
    const headers = new Headers({'Authorization': localStorage.getItem('authorizationToken')});
    const options = new RequestOptions({headers: headers});
    const requestId = payload;
    const url = '/api/requests/'+ requestId +'/events'

    return Observable.interval(500)
        .flatMap(()=> {
            return this.http
                .get(url, options)
                .map(response => {
                    const request = response.json();
                    return request.map(request => {
                        return new RequestTask(request)
                    });
                }).catch(this.handleError);
        })

}

我认为我的错误来自Observable，但我看不出如何解决它