angular http 拦截器

import { Injectable } from '@angular/core';
import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpResponse, HttpErrorResponse } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { timeout, delay, retryWhen, scan, tap, catchError  } from 'rxjs/operators';
import { mergeMap } from 'rxjs/operators';
import { AuthService } from '../service/auth-service/AuthService.service'
import { Router } from '@angular/router';
/** Pass untouched request through to the next request handler. */

import { MessageProvider } from "../tools/message";

/** 超时时间 */
const DEFAULTTIMEOUT = 5000;

/** 最大重试次数 */
const MAXRETRYCOUNT = 3;

/** 防止重复点击 网络重复请求 */
const MAXDEBOUNCETIME = 1000;

@Injectable()
export class NoopInterceptor implements HttpInterceptor {

  constructor(
    private authService: AuthService, 
    private router: Router, 
    private messagePvd: MessageProvider
    ) { 
  };
  
  intercept(req: HttpRequest, next: HttpHandler):Observable> {
    // console.log('test ckick3');
    let time = new Date().getTime();
    let accessToken: string = this.authService.getAuthToken() ? this.authService.getAuthToken() : "";
    const authReq = req.clone({
      setHeaders: {
        // REQUEST_FROM: "WEB_OFFICIAL",
        Ver: "1.0.17",
        TIMESTAMP: time.toString(),
        ACCESS_TOKEN: accessToken,
        Authentication: "web:fkasfklasjfklwejiwefsklfsjfiwej="
      }
    });
    // ACCESS_TOKEN:accessToken}});

    return next.handle(authReq).pipe(
      debounceTime(MAXDEBOUNCETIME),
      timeout(DEFAULTTIMEOUT),
      retryWhen(err$ => {
        // 重试
        return err$.pipe(
          scan((errCount, err) => {
            if (errCount >= MAXRETRYCOUNT) {
              throw err;
            }
            return errCount + 1;
          }, 0),
          delay(1000),
          tap(errCount => {
            // 副作用
            if (errCount == 1) {
              // 第一次重试时，提示用户
              this.messagePvd.errorMsg('网络超时,正在重新请求中...');
            }
          })
        )
      }),
      catchError((err: HttpErrorResponse) => {
        this.messagePvd.errorMsg('网络超时, 请重试');
        return throwError('网络超时' + err.name + err.message)
      }),
      mergeMap((event: any) => {
        if (event instanceof HttpResponse && event.status != 200) {
          return Observable.create(event);
        } 
        
        if (event instanceof HttpResponse && event.body.code == 2) {
          this.messagePvd.errorMsg(event.body.msg);
          this.router.navigate(['/passport']);
          return Observable.create(event);
        }
        
        if (event instanceof HttpResponse && event.body.code != undefined && event.body.code != 0) {
          this.messagePvd.errorMsg(event.body.msg);
          return Observable.create(event);
        }

        return Observable.create(observer => observer.next(event)); //请求成功返回响应

      }),
      catchError((err: HttpErrorResponse) => {
        switch (err.status) {
          case 401: 
            this.messagePvd.errorMsg('服务器错误代码:401');
            console.log(err);
          break;
          case 403:
            this.messagePvd.errorMsg('服务器错误代码:403');
            console.log(err);
            break;
          case 404:
            this.messagePvd.errorMsg('服务器错误代码:404');
            console.log(err);
            break;
          case 500:
            this.messagePvd.errorMsg('服务器错误代码:500');
            console.log(err);
            break;
          case 502:
            this.messagePvd.errorMsg('服务器错误代码:502');
            console.log(err);
            break;
          default:
            console.log(err);
            break;
        }
        return throwError(err.status);
      })
    );
  }
}

注意：

1.这是自己根据网上各种大神的拦截器copy过来，改造的拦截器，不足请指正

2.MessageProvider 是自己封装的消息弹出系统，拷贝过去不能使用，直接删除相关代码即可，不影响使用

3. https://angular.cn/guide/http#intercepting-requests-and-responses