当令牌在角度4中过期时如何重定向到注销

Question

我有一个 Angular 4 应用程序。我在那里使用 JWT 令牌进行身份验证。一切正常。但是我给 JWT 令牌的令牌过期时间是 1 小时。一旦令牌在服务器端过期，我想将用户从前端应用程序中注销。在节点后端，我使用快速中间件通过检查所有请求是否包含有效令牌来处理此问题。有没有办法做到这一点？

Answer 1

您可以使用 Http 拦截器。如果有任何未经授权的 401 响应。假设您正在发送带有标头中令牌的 http 请求。您的服务器端代码检查您的令牌，最后发现，令牌无效/过期返回 401 代码，您可以将用户重定向到登录页面。并且手动传递令牌并检查所有授权/未授权的http请求是非常重复的工作，您可以通过拦截器作为http请求的委托来完成这项常见任务。查看代码示例，您将获得解决方案。

AppHttpInterceptor.ts

import { Injectable } from "@angular/core";
import {
    HttpInterceptor,
    HttpRequest,
    HttpResponse,
    HttpErrorResponse,
    HttpHandler,
    HttpEvent
} from '@angular/common/http';

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/do';
import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/throw';
import { Http, Response, RequestOptions, Headers } from '@angular/http';
import { Router } from '@angular/router'


@Injectable()
export class AppHttpInterceptor implements HttpInterceptor {
    constructor(private router: Router){

    }
    headers = new Headers({
        'Content-Type': 'application/json',
        'Token': localStorage.getItem("Token")
    });
    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {

        console.log("intercepted request ... ");

        // Clone the request to add the new header.
        const authReq = req.clone({ headers: req.headers.set("Token", localStorage.getItem("Token")) });

        console.log("Sending request with new header now ...");

        //send the newly created request
        return next.handle(authReq)
            .catch(err => {
                // onError
                console.log(err);
                if (err instanceof HttpErrorResponse) {
                    console.log(err.status);
                    console.log(err.statusText);
                    if (err.status === 401) {
                        window.location.href = "/login";
                    }
                }
                return Observable.throw(err);
            }) as any;
    }
}

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { HttpModule } from '@angular/http';
import { HttpClient } from "@angular/common/http";
import { FormsModule } from '@angular/forms';
import { ToasterModule, ToasterService } from "angular2-toaster";
import { BrowserAnimationsModule } from '@angular/platform-browser /animations';
import { RouterModule } from '@angular/router';
import { ReactiveFormsModule } from '@angular/forms';
import { HttpClientModule,HTTP_INTERCEPTORS} from '@angular/common/http';
import {AppHttpInterceptor} from './Common/AuthInterceptor';
import { AppRoutes } from '../app/Common/Routes';
import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent,
  ],
  imports: [
    BrowserModule, HttpModule,HttpClientModule, ReactiveFormsModule, FormsModule, BrowserAnimationsModule, RouterModule.forRoot(AppRoutes)
  ],
 providers: [
 {
   provide: HTTP_INTERCEPTORS,
   useClass: AppHttpInterceptor,
   multi: true
 }
],
bootstrap: [AppComponent]
})
export class AppModule { 
  constructor(private httpClient: HttpClient){
    this.httpClient.get("https://jsonplaceholder.typicode.com/users").subscribe(
  success => {
    console.log("Successfully Completed");
    console.log(success);
  }
  );
 }

}

Answer 2

您可以检查令牌是否过期，作为响应，您可以重定向到登录页面 将令牌存储在本地存储中 例如

 yourmthod(parametr) {
        this.token = localStorage.getItem("token");
        this.headers = new Headers();
        this.headers.delete(this.token);
        this.headers.append("Authorization", this.token);
        return this._http.post(Constants.SERVER_URL + 'your method', {headers: this.headers});
    }

所以它会响应 401 错误，您可以通过重定向到您的登录页面来处理此问题

如有任何疑问，您可以在 cmets 中提出问题，以便我可以帮助您

你也可以在你的方法中使用 if-else

你可以在app.component.ts中用onIt()方法写代码

ngOnInit(): void {
        let token = localStorage.getItem("token");
        if (token) {
            this.isTokenAvaialable = true;
            this.http.get(Constants.SERVER_URL + 'your mthod to validate token' + token).subscribe(data => {
                if (data == true) {
                    if (window.location.pathname == "") {
                        this.router.navigate(['/home', {outlets: {'r2': ['dashboard']}}]);
                    }
                } else if (data == false) {

                    this.logout('Server restarted.Please login again!!');
                } else {

                    this.logout('Session expired.Please login again.!!');
                }

            }, (err: HttpErrorResponse) => {
                this.toastr.warning('Server restarted.Please login again!!', 'Alert');
                localStorage.removeItem("token");
                this.isTokenAvaialable = false;
                this.logout('Server restarted.Please login again!!');
            });
        } else {
            this.isTokenAvaialable = false;
            this.router.navigate(['']);
            localStorage.removeItem("token");
            this.isTokenAvaialable = false;
        }
    }

Answer 3

angular2-jwt 中有 tokenNotExpired 方法，您可以使用它来检查令牌过期时间

试试这个

  authHttpGet(URL: string): Observable<any> {
    if (!tokenNotExpired('id_token')) {
      this._route.navigate(['login']);
    }
  }