如何在 angular 4 中令牌过期时重定向到注销

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 令牌的令牌到期时间是 1 小时。一旦令牌在服务器端过期，我想从前端应用程序中注销用户。在节点后端，我使用 express 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。 angular 这边也有方法吗？

Answer 1

angular2-jwt 中有 tokenNotExpired 方法，你可以用它来检查令牌过期

试试这个

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

Answer 2

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 header 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，令牌是 invalid/expire return 401 代码，您可以将用户重定向到登录页面。手动传递令牌并检查所有 http 请求 authorized/unauthorized 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 3

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这个问题

如有任何疑问，您可以在评论中提出问题，以便我为您提供帮助

你也可以在你的方法中使用 if-else

你可以在onIt()方法

中编写app.component.ts中的代码

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;
        }
    }

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