Angular 5/HttpInterceptor/Detect(已取消)xhr

Question

在我的角度应用程序中,我看到chrome(取消)api调用太快了.我还有一个HttpInterceptor,如果请求没有完成,它会在500ms后触发每个HttpClient请求的加载指示符.但是,对于获取(取消)的请求,似乎没有任何新事件随后隐藏我的加载指示器.

有没有办法在HttpInterceptor中检测"已取消"的请求,以便我可以再次隐藏我的加载指示器？

export class GlobalHttpInterceptor implements HttpInterceptor {
constructor(
private sessionService: SessionService,
private loadingService: LoadingService
) { }

intercept(
req: HttpRequest<any>,
next: HttpHandler
): Observable<HttpEvent<any>> {

setTimeout(() => {
  if (showLoading) {
    this.loadingService.show();
  }
}, 500);
let showLoading = true;

if (this.sessionService.headers.length > 0) {
  for (const x of this.sessionService.headers) {
    req = req.clone({
      headers: req.headers.set(x.key, x.value)
    });
  }
}

return next.handle(req)
  .do(
    (response) => {
      if (response instanceof HttpResponse) {
        showLoading = false;
        this.loadingService.hide();
      }
    },
    (error) => {
      showLoading = false;
      this.loadingService.hide();
    });
}
}

Answer 1

刚遇到同样的问题.即使取消http请求,finalize运算符似乎也会触发.

public intercept(
    request: HttpRequest<any>,
    next: HttpHandler
): Observable<HttpSentEvent | HttpHeaderResponse | HttpProgressEvent | HttpResponse<any> | HttpUserEvent<any>> {
    // request starts

    return next.handle(request).pipe(
        finalize(() => {
            // request completes, errors, or is cancelled
        })
    );
}

Answer 2

扩展戴维的回答，这就是我检测中止请求的方式。

正如他所说，finalize 将始终在可观察源完成时运行，在这种情况下，它要么是成功响应，要么是错误响应，要么是中止的请求。

我的方法的关键是跟踪您目前收到的信息。

intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
  let lastResponse: HttpEvent<any>;
  let error: HttpErrorResponse;

  return next.handle(request)
    .pipe(
      tap((response: HttpEvent<any>) => {
        lastResponse = response;
        if (response.type === HttpEventType.Response) {
          console.log('success response', response);
        }
      }),
      catchError((err: any) => {
        error = err;
        console.log('error response', err);
        // TODO: error handling if required
        return throwError(err);        
      }),    
      finalize(() => {
        if (lastResponse.type === HttpEventType.Sent && !error) {
          // last response type was 0, and we haven't received an error
          console.log('aborted request');
        }
      })
    );
}