浅谈angular9中拦截器的用途

本篇文章和大家一起聊聊angular9中拦截器的使用。有必然的参照 价值，有需要的伴侣可以参照 一下，但愿对大家有所帮忙。

相关教程引荐：《angular教程》

拦截器统一增加token

我们在做一个后台治理系统时,需要给每个恳求的恳求头里面增加token,所以下面我们来理解一下angular的拦截器,并使用

拦截器使用

1.创立http.service.ts,用于网络恳求

import { Injectable } from '@angular/core';import { HttpClient } from '@angular/common/http';@Injectable({
  providedIn: 'root'})export class HttpService {

  constructor(private http: HttpClient) { }
  getData () {
    return this.http.get('/assets/mock/data.json')
  }}

2.创立noop.interceptor.ts,拦截器实现代码

import { Injectable } from '@angular/core';import {
  HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpResponse} from '@angular/common/http';import { Observable } from 'rxjs';import { tap } from 'rxjs/operators';import { Router } from '@angular/router';/** Pass untouched request through to the next request handler. */@Injectable()export class NoopInterceptor implements HttpInterceptor {
    constructor (private router: Router) {}
  intercept(req: HttpRequest<any>, next: HttpHandler):
    Observable<HttpEvent<any>> {
    // 拦截恳求,给恳求头增加token
    let url = req.url // 可以对url停止处置
    let token = document.cookie && document.cookie.split("=")[1]
    // 登录恳求排除在外
    // if (!url.includes('login')) {
        req = req.clone({
            url, // 处置后的url,再赋值给req
            headers: req.headers.set('Authorization', token)//恳求头统一增加token
        })
    // }
    return next.handle(req).pipe(
        tap(
         event => {
          if (event instanceof HttpResponse) {
           console.log(event);
           if (event.status >= 500) {
            // 处置错误
           }
          }
         },
         error => {
          // token过期 效劳器错误等处置
        //   this.router.navigate(['/login']);
         })
       );
  }}

3.在app.module.ts中使用

3.1imports中引入HttpClientModule

3.2HttpService的注册

3.3NoopInterceptor拦截器的使用

import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';import { HttpService } from './auth/http.service';import { NoopInterceptor } from './auth/noop.interceptor';@NgModule({
   imports: [
      BrowserModule,
      HttpClientModule,
      AppRoutingModule   ],
   providers: [
      HttpService,
      { provide: HTTP_INTERCEPTORS, useClass: NoopInterceptor, multi: true }
   ],
   // ... 省略})

拦截器实现后的结果

拦截器一样配合路由保卫一起使用。