我如何每1秒钟致电服务并使用angular2检查响应？

Question

我执行了以下服务，

export class UploadPollingService {
    constructor(private http: Http, private appConfig: AppConfigService) { }
    checkUploadInfo(term: string, ): Observable<Event[]> {
        return this.http
            .get(this.appConfig.getAPIUrl() + `/checkStatus?processId=${term}`)
            .map(this.extractData)
            .catch(this.handleErrors);
    }

我在组件内部使用它，我想每1秒调用一次此服务并检查状态，基本上是进行轮询。怎么做？

this.uploadPollingService.checkUploadInfo()

Answer 1

您必须timeinterval像这样使用您的服务方法

   ngOnInit(){
   this.interval = setInterval(() => {
        this.checkUpdate();
    }, 1000);
   }

    ngOnDestroy() {
    if (this.interval) {
        clearInterval(this.interval);
    }
   }

  checkUpdate(){
    this.uploadPollingService.checkUploadInfo()
      .subscribe(res => {
        console.log(res, "Response here");
      },
      err => {
        console.log(err);
      })
  }
  ....



  export class UploadPollingService {
    constructor(private http: Http, private appConfig: AppConfigService) { }
    checkUploadInfo(term?: string): Observable<Event[]> {
        return this.http
            .get(this.appConfig.getAPIUrl() + `/checkStatus?processId=${term}`)
            .map( res => {
              return [{ status: res.status, json: res.json() }]
            })
            .catch(this.handleErrors);
    }