examSystem-Anxin/src/app/http-interceptors/base-interceptor.ts

import { Injectable } from '@angular/core';
import {
  HttpClient, HttpEvent, HttpInterceptor, HttpHandler, HttpRequest,
  HttpErrorResponse
} from '@angular/common/http';
import { throwError } from 'rxjs'
import { catchError, retry } from 'rxjs/operators';
import { Router,ActivatedRoute } from '@angular/router'
import { CacheTokenService } from './cache-token.service'
import { IsLoginService } from '../is-login.service'
import { MatSnackBar, MatSnackBarConfig } from '@angular/material/snack-bar';

//baseurl
// const baseurl = 'http://39.106.78.171:8008';

@Injectable()
export class BaseInterceptor implements HttpInterceptor {

  constructor(private http:HttpClient,private router:Router,private route:ActivatedRoute,public token:CacheTokenService,public snackBar: MatSnackBar,public isLogin: IsLoginService) {}

  intercept(req, next: HttpHandler) {

    let newReq = req.clone({
      url: req.hadBaseurl ? `${req.url}` : `${req.url}`,
    });
    if(!req.cancelToken) {
      /*获取token*/
      let token = sessionStorage.getItem("token") || ''
      /*此处设置额外请求头，token令牌*/
      newReq.headers =
      newReq.headers.set('Authorization', `Bearer ${token}`)
    }

    // 携带请求头发送下一次请求
    return next.handle(newReq)
      .pipe(
        //箭头函数,注意this指向
        catchError((err) => this.handleError(err))
      )
  }

  // 捕获错误  
  //401 token过期   403没权限!!!   400参数错误   404未找到   614刷新令牌过期!!!

  private handleError(error: HttpErrorResponse) {
    // 用户认证失败返回登录页
    if (error.status === 401||error.status === 614) {
      sessionStorage.clear()
      this.router.navigate(['/login'])
      const config = new MatSnackBarConfig();
      config.verticalPosition = 'top';
      config.duration = 3000
      this.snackBar.open('用户认证信息过期,请重新登录','确定',config);
    }
    if (error.status === 403) {
      const config = new MatSnackBarConfig();
      config.verticalPosition = 'top';
      config.duration = 3000
      this.snackBar.open('对不起,您无此权限','确定',config);
    }
    if (error.status === 400) {
      const config = new MatSnackBarConfig();
      config.verticalPosition = 'top';
      config.duration = 3000
      this.snackBar.open('您输入的参数有误','确定',config);
    }

    if (error.error instanceof ErrorEvent) {
      // 发生客户端或网络错误。相应处理。
      console.error('An error occurred:', error.error.message);
    } else {
      // 服务端返回http状态码
      // 服务端返回错误信息
      console.error(
        `Backend returned code ${error.status}, ` +
        `body was: ${error.error}`);
    }
    // 返回带有面向用户的错误信息
    return throwError(
      error.error);
  };
}