Angular拦截器，处理HTTP错误并重试

Question

我有一个基本的 JWT 系统，以及一个检查请求是否因未授权而失败的拦截器。

import {Injectable} from '@angular/core';
import {HttpErrorResponse, HttpEvent, HttpHandler, HttpInterceptor, HttpRequest} from '@angular/common/http';
import {Observable, throwError} from 'rxjs';
import {AuthService} from '../services/auth.service';
import {catchError, retryWhen} from 'rxjs/operators';

@Injectable()
export class AuthenticationErrorInterceptor implements HttpInterceptor {

  private readonly _authService: AuthService;

  constructor(authService: AuthService) {
    this._authService = authService;
  }

  public intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const authReq = req.clone({headers: req.headers});
    return next.handle(authReq)
      .pipe(
        catchError((err) => this._handleAuthError(err)),
        retry(3)
      );
  }

  private _handleAuthError(error: HttpErrorResponse): Observable<any> {
    if (error.status === 401 || error.status === 403) {
      return this._authService.authenticate();
    }

    return throwError(error);
  }
}

如果请求确实失败，那么我想在调用 this._authService.authenticate(); 后重新发送请求。它将重新进行身份验证，因为错误处理迫使它重新进行身份验证，但在我刷新浏览器之前它不会回忆起导致应用程序失败的请求。

我怎样才能让我的守卫再次尝试请求？

我也尝试过使用 retryWhen，但我得到了 same/similar 结果。

Answer 1

在您拥有 re-authenticated 您的 session 之后，在 HTTP 处理程序上调用 .next。理想情况下，您应该 return 来自您的身份验证方法的身份验证令牌，然后可以将其附加到请求 auth headers.

import {Injectable} from '@angular/core';
import {HttpErrorResponse, HttpEvent, HttpHandler, HttpInterceptor, HttpRequest} from '@angular/common/http';
import {Observable, throwError} from 'rxjs';
import {AuthService} from '../services/auth.service';
import {catchError, retryWhen} from 'rxjs/operators';

@Injectable()
export class AuthenticationErrorInterceptor implements HttpInterceptor {

  private readonly _authService: AuthService;

  constructor(authService: AuthService) {
    this._authService = authService;
  }

  public intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
      return next.handle(req)
            .pipe(
                catchError((error: HttpErrorResponse) => {
                  if (error.status === 401 || error.status === 403) {
                    return this._authService.authenticate()
                      .pipe(
                        mergeMap((token) => next.handle(req.clone({
                                    headers: req.headers.set(AUTH_TOKEN_NAME_HERE, token)
                                })))
                      );
                  }

                    return throwError(error);
                })
            );
  }
}

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