Angular HTTP拦截器如何链接可观察的 [英] Angular HTTP Interceptor how to chain an observable

问题描述

我正在使用Azure AD adal库进行身份验证。有一个调用来获取返回可观察值的令牌。如何将此可观察值添加到截距中？在下面的示例中，如何获取在订阅中设置的请求以Observable的形式返回？

I am using the Azure AD adal library to do authentication. There is a call to aquire a token that returns an observable. How can this observable be added into the intercept? In the below example, how can I get the request that is set inside the subscribe to be returned as the Observable?

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    this.authAzureService.getAccessToken()
    .subscribe(token => {
      // I need this to be returned
      request = this.getRequestWithHeaders(request, token);
    });

    // This returns the request before the access token is added
    return next.handle(request);
  }

推荐答案

感谢@Commercial Suicide I找到了解决方案，那就是使用flatMap。这是有效的代码：

Thanks to @Commecial Suicide I found the solution, which is to use a flatMap. Here is the code that worked:

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    let requestHandler = this.authAzureService.getAccessToken()
    .flatMap(token => {
      request = this.getRequestWithHeaders(request, token);
      return next.handle(request);
    });
    return requestHandler;
  }

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