Angular 5 HttpInterceptor 重试请求 [英] Angular 5 HttpInterceptor Retry Request

问题描述

Angluar 5 HttpInterceptor 如何在出错时重试请求?

How can an Angluar 5 HttpInterceptor retry a request on error?

Angular 文档没有显示 HttpInterceptor 重试的示例:https://angular.io/guide/httphttps://angular.io/api/common/http/HttpInterceptor

The Angular docs don't show an example of an HttpInterceptor retry: https://angular.io/guide/http https://angular.io/api/common/http/HttpInterceptor

请注意，对 HttpClient 对象进行了重试.这在这种情况下没有帮助.

Note that there is a retry on the HttpClient object. This is NOT helpful in this case.

我试图实现的伪逻辑:发送请求IF 错误响应 THEN 更改请求并重试请求.

Psuedo logic I'm trying to achieve: Send request IF error response THEN change the request and retry the request.

此 HttpInterceptor 成功运行请求并捕获错误但不重试请求.

This HttpInterceptor successfully runs the request and catches the error but doesn't retry the request.

export class AuthInterceptor implements HttpInterceptor {
    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {

        return next
            .handle(req)
            .do(event => {
            }, (err: any) => {
                let reqRepeat = req.clone(); // For now, keep it simple. Don't change original request.
                return next.handle(req); // Retry request. THIS DOESN'T SEEM TO DO ANYTHING!
            })
    }
};

推荐答案

rxjs 'do' 操作符不会修改观察者.返回 '​​next.handle(...)' 不应该工作.

The rxjs 'do' operator does not modify the observer. Returning the 'next.handle(...)' should not work.

尝试改用catch"运算符.

Try to use the 'catch' operator instead.

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    return next.handle(req).catch(() => {
      const newReq = req.clone();
      return next.handle(newReq);
    });
  }

不要忘记导入 catch 操作符:

Do not forget to import the catch operator:

import 'rxjs/add/operator/catch';

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