Angular 9 JWT用户认证

川长思鸟来 2023-06-16 10:35 31阅读 0赞

## 创建Angular 9项目 ##

ng new angular-meanstack-authentication  
转到Angular用户身份验证项目文件夹  
cd angular-meanstack-authentication  
创建以下组件  
ng g c components/signin  
ng g c components/signup  
ng g c components/user-profile  
安装Bootstrap 4  
npm install bootstrap  
在angular.json文件中添加Bootstrap 4样式表路径  
"styles": \[  
  "node\_modules/bootstrap/dist/css/bootstrap.min.css",  
  "src/styles.css"  
 \]  
启动Angular应用  
ng serve --open

##    克隆基于Node.js令牌的身份验证REST API ##

git clone https://github.com/SinghDigamber/node-token-based-authentication.git  
进入服务器文件夹  
cd node-token-based-authentication  
运行\`npm install\`以安装所需的软件包  
打开其他终端运行 \`mongod\`  
安装nodemon软件包  
当服务器文件中发生任何更改时，它有助于启动节点服务器。  
npm install nodemon --save-dev  
打开终端运行 \`nodemon\`

API Methods			API URL
    GET (Users List)	/api
    POST (Sign in)		/api/signin
    POST (Sign up)		/api/register-user
    GET (User Profile)	/api/user-profile/id
    PUT (Update User)	/api/update-user/id
    DELETE (Delete User)	/api/delete-user/id

##    设置HttpClient ##

HttpClientModule在app.module.ts文件中导入服务。

import { HttpClientModule } from '@angular/common/http';
    @NgModule({
      imports: [
        HttpClientModule
       ]
    })

##    创建用户身份验证服务 ##

在共享文件夹内创建shared/user.ts文件，并在其中包含以下代码。

export class User {
      id: string;
      name: string;
      email: string;
      password: string;
    }

接下来，运行以下命令以创建用户身份验证服务。  
ng g s shared/auth  
将以下代码添加到shared / auth.service.ts文件中。

import {Injectable} from '@angular/core';
    import {User} from './user';
    import {Observable, throwError} from 'rxjs';
    import {catchError, map} from 'rxjs/operators';
    import {HttpClient, HttpErrorResponse, HttpHeaders} from '@angular/common/http';
    import {Router} from '@angular/router';
    
    @Injectable({
      providedIn: 'root'
    })
    
    export class AuthService {
      endpoint = 'http://localhost:4000/api';
      headers = new HttpHeaders().set('Content-Type', 'application/json');
      currentUser = {};
    
      constructor(
        private http: HttpClient,
        public router: Router
      ) {
      }
    
      // Sign-up
      signUp(user: User): Observable<any> {
        const api = `${this.endpoint}/register-user`;
        return this.http.post(api, user)
          .pipe(
            catchError(this.handleError)
          );
      }
    
      // Sign-in
      signIn(user: User) {
        return this.http.post<any>(`${this.endpoint}/signin`, user)
          .subscribe((res: any) => {
            localStorage.setItem('access_token', res.token);
            this.getUserProfile(res._id).subscribe((res) => {
              this.currentUser = res;
              this.router.navigate(['user-profile/' + res.msg._id]);
            });
          });
      }
    
      getToken() {
        return localStorage.getItem('access_token');
      }
    
      get isLoggedIn(): boolean {
        const authToken = localStorage.getItem('access_token');
        return (authToken !== null) ? true : false;
      }
    
      doLogout() {
        const removeToken = localStorage.removeItem('access_token');
        if (removeToken == null) {
          this.router.navigate(['log-in']);
        }
      }
    
      // User profile
      getUserProfile(id): Observable<any> {
        const api = `${this.endpoint}/user-profile/${id}`;
        return this.http.get(api, {headers: this.headers}).pipe(
          map((res: Response) => {
            return res || {};
          }),
          catchError(this.handleError)
        );
      }
    
      // Error
      handleError(error: HttpErrorResponse) {
        let msg = '';
        if (error.error instanceof ErrorEvent) {
          // client-side error
          msg = error.error.message;
        } else {
          // server-side error
          msg = `Error Code: ${error.status}\nMessage: ${error.message}`;
        }
        return throwError(msg);
      }
    }

signUp()将存储的MongoDB数据库的用户名，电子邮件地址和密码。  
通过使用bcryptjs，我们将密码安全地存储在数据库中。  
signIn()方法允许使用JSON网络令牌由节点服务器生成的用户在应用程序的访问。  
我们从API响应中获取JWT令牌并存储在本地存储中，然后在getToken方法中，我们通过本地存储getItem方法访问该令牌。  
该isLoggedIn如果用户在其他人返回false记录方法返回true。

## **使用Angular 9 HttpInterceptor设置JWT令牌** ##

在共享文件夹中创建**authconfig.interceptor.ts**文件

import {Injectable} from '@angular/core';
    import {HttpHandler, HttpInterceptor, HttpRequest} from '@angular/common/http';
    import {AuthService} from './auth.service';
    
    @Injectable()
    
    export class AuthInterceptor implements HttpInterceptor {
      constructor(private authService: AuthService) {
      }
    
      intercept(req: HttpRequest<any>, next: HttpHandler) {
        // 获取JWT令牌
        const authToken = this.authService.getToken();
        // 设置Authorization标头
        req = req.clone({
          setHeaders: {
            Authorization: 'Bearer ' + authToken
          }
        });
        return next.handle(req);
      }
    }

在**app.module.ts**文件中导入**HTTP\_INTERCEPTORS**并在数组中设置

providers: [{
        provide: HTTP_INTERCEPTORS,
        useClass: AuthInterceptor,
        multi: true
      }],

## **使用CanActivate保护路线** ##

运行以下命令来设置[CanActivate接口类][CanActivate]，它会阻止访问者访问应用程序中的某些URL。我们只希望登录用户访问`/user-profile`

ng g guard shared/auth

**auth.guard.ts**文件中添加以下代码

import {Injectable} from '@angular/core';
    import {ActivatedRouteSnapshot, CanActivate, Router, RouterStateSnapshot} from '@angular/router';
    import {Observable} from 'rxjs';
    import {AuthService} from './../shared/auth.service';
    
    @Injectable({
      providedIn: 'root'
    })
    export class AuthGuard implements CanActivate {
    
      constructor(
        public authService: AuthService,
        public router: Router
      ) {
      }
    
      canActivate(
        next: ActivatedRouteSnapshot,
        state: RouterStateSnapshot): Observable<boolean> | Promise<boolean> | boolean {
        if (this.authService.isLoggedIn !== true) {
          window.alert('Access not allowed!');
          this.router.navigate(['log-in']);
        }
        return true;
      }
    }

**app-routing.module.ts**文件导入AuthGuard接口类

import {NgModule} from '@angular/core';
    import {RouterModule, Routes} from '@angular/router';
    
    import {SigninComponent} from './components/signin/signin.component';
    import {SignupComponent} from './components/signup/signup.component';
    import {UserProfileComponent} from './components/user-profile/user-profile.component';
    
    import {AuthGuard} from './shared/auth.guard';
    
    
    const routes: Routes = [
      {path: '', redirectTo: '/log-in', pathMatch: 'full'},
      {path: 'log-in', component: SigninComponent},
      {path: 'sign-up', component: SignupComponent},
      {path: 'user-profile/:id', component: UserProfileComponent, canActivate: [AuthGuard]}
    ];
    
    @NgModule({
      imports: [RouterModule.forRoot(routes)],
      exports: [RouterModule]
    })
    
    export class AppRoutingModule {
    }

## Implement Angular 9 Reactive Forms ##

# Angular 9 JWT User Authentication Tutorial #

By **Digamber Rawat** Last updated on **November 9, 2019**

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**Welcome, fellas! Today, In this step-by-step Angular 8|9 tutorial, we are going to understand how to build a secure user authentication system using JSON web tokens (JWT) and RESTful Auth APIs built with express, node and mongoDB.**

We will be using the token-based user authentication RESTful APIs which we covered in our earlier tutorial. Learn [how to build secure (JWT) Token-Based RESTful authentication API with Node/Express Js?][how to build secure _JWT_ Token-Based RESTful authentication API with Node_Express Js] from scratch.

### What is JWT (JSON Web Token)? ###

JWT refers to JSON Web token. It’s a token in string form validated and generated by a web server. This string-based token helps in communicating between the client and the server.

Let’s understand how does the JWT help in transferring the data securely between the client and the server.

User information is sent to the client like username and password using an HTTP POST request to the webserver. Web server identifies the user information and creates a token and send it back to the client. Client store that token into local storage or a session and also set it to the header. On the next HTTP call, that token is verified by the server, and web server returns the response to the client.

## Angular 9 MEAN Stack User Authentication Work Flow ##

*  User can sign-in
 *  User can register or sign-up
 *  Store user data on MongoDB database.
 *  Creating Angular service to handle user auth API.
 *  Hide certain menu item based on authentication state
 *  Restrict user to access user profile page when the user is not logged-in.
 *  Store JWT token in local storage to manage the user session in Angular 8/9
 *  Store password in mongoDB Database using the password hash method with bcryptjs.
 *  Generate a JSON web token when a user logs in and store that token in a authorization header using HttpInterceptor class.

Click below to get the full code of this tutorial on GitHub.

[Git Repo][]

Table of contents

1.  [Set up Angular 9 Project][]
2.  [Clone Node Js Token-Based Auth REST API from GitHub][]
3.  [Setting up HttpClient][]
4.  [Creating User Authentication Service in Angular 9][]
5.  [Set JWT Token with Angular 9 HttpInterceptor][]
6.  [Protect Routes with CanActivate][]
7.  [Implement Reactive Forms][]
8.  [Implementing User Registration in MEAN Stack App][]
9.  [Handling MEAN Stack Login with Angular 9][]
10. [Fetch User Profile in Angular 9 Auth App][]
11. [Conclusion][]

## Set up Angular 9 Project ##

Let’s get started by installing the basic Angular app, enter the following command in your terminal:

ng new angular-meanstack-authentication
    
    # ? Would you like to add Angular routing? Yes
    # ? Which stylesheet format would you like to use? CSS

Next, head over to the Angular user authentication project folder:

cd angular-meanstack-authentication

To make things simpler create a separate front-end and backend (server) in Angular app. Our Angular 8/9 user auth app will have **signin**, **signup** and **user-profile** pages.

Create specific **components** folder in **src/app/components** in Angular app and create the following components in it.

ng g c components/signin
    
    ng g c components/signup
    
    ng g c components/user-profile

Next, install Bootstrap 4.

npm install bootstrap

Add the Bootstrap 4 stylesheet path in **angular.json** file.

"styles": [
              "node_modules/bootstrap/dist/css/bootstrap.min.css",
              "src/styles.css"
             ]

Start your Angular app.

ng serve --open

## Clone Node Js Token-Based Auth REST API from GitHub ##

Run the following command to clone **Node.js token-based auth REST API** from GitHub in your Angular’s root folder.

git clone https://github.com/SinghDigamber/node-token-based-authentication.git

Get inside the server folder:

cd node-token-based-authentication

Next, install npm packages to set up and start the Node server:

**Run `` `npm install` `` to install required packages**

**Open other terminal run `` `mongod` ``**

Next, install the nodemon NPM package for development purpose with `--save-dev` attribute, it helps in starting the node server when any change occurs in the server files.

npm install nodemon --save-dev

Open terminal run `` `nodemon` ``

Following auth APIs we are going to use in this tutorial.

<table> 
 <thead> 
  <tr> 
   <th>API Methods</th> 
   <th>API URL</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td><strong>GET (Users List)</strong></td> 
   <td>/api</td> 
  </tr> 
  <tr> 
   <td><strong>POST (Sign in)</strong></td> 
   <td>/api/signin</td> 
  </tr> 
  <tr> 
   <td><strong>POST (Sign up)</strong></td> 
   <td>/api/register-user</td> 
  </tr> 
  <tr> 
   <td><strong>GET (User Profile)</strong></td> 
   <td>/api/user-profile/id</td> 
  </tr> 
  <tr> 
   <td><strong>PUT (Update User)</strong></td> 
   <td>/api/update-user/id</td> 
  </tr> 
  <tr> 
   <td><strong>DELETE (Delete User)</strong></td> 
   <td>/api/delete-user/id</td> 
  </tr> 
 </tbody> 
</table>

Open API URL on [http://localhost:4000/api][http_localhost_4000_api]

## Setting up HttpClient ##

To handle REST APIs via HTTP requests in our Angular user authentication app. We need to import [Angular HttpClient service][] in the auth module.

Import `HttpClientModule` service in `app.module.ts` file.

import { HttpClientModule } from '@angular/common/http';
    
    @NgModule({
      imports: [
        HttpClientModule
       ]
    })

## Creating User Authentication Service in Angular 9 ##

Now create Angular auth service and user class, these files will handle all the **JWT user authentication** related APIs in our project.

Inside the shared folder create `shared/user.ts` file and include the following code inside of it.

export class User {
        _id: String;
        name: String;
        email: String;
        password: String;
    }

Next, run below command to create user auth service.

ng g s shared/auth

Add the following code in the **shared/auth.service.ts** file.

import { Injectable } from '@angular/core';
    import { User } from './user';
    import { Observable, throwError } from 'rxjs';
    import { catchError, map } from 'rxjs/operators';
    import { HttpClient, HttpHeaders, HttpErrorResponse } from '@angular/common/http';
    import { Router } from '@angular/router';
    
    @Injectable({
      providedIn: 'root'
    })
    
    export class AuthService {
      endpoint: string = 'http://localhost:4000/api';
      headers = new HttpHeaders().set('Content-Type', 'application/json');
      currentUser = {};
    
      constructor(
        private http: HttpClient,
        public router: Router
      ) {
      }
    
      // Sign-up
      signUp(user: User): Observable<any> {
        let api = `${this.endpoint}/register-user`;
        return this.http.post(api, user)
          .pipe(
            catchError(this.handleError)
          )
      }
    
      // Sign-in
      signIn(user: User) {
        return this.http.post<any>(`${this.endpoint}/signin`, user)
          .subscribe((res: any) => {
            localStorage.setItem('access_token', res.token)
            this.getUserProfile(res._id).subscribe((res) => {
              this.currentUser = res;
              this.router.navigate(['user-profile/' + res.msg._id]);
            })
          })
      }
    
      getToken() {
        return localStorage.getItem('access_token');
      }
    
      get isLoggedIn(): boolean {
        let authToken = localStorage.getItem('access_token');
        return (authToken !== null) ? true : false;
      }
    
      doLogout() {
        let removeToken = localStorage.removeItem('access_token');
        if (removeToken == null) {
          this.router.navigate(['log-in']);
        }
      }
    
      // User profile
      getUserProfile(id): Observable<any> {
        let api = `${this.endpoint}/user-profile/${id}`;
        return this.http.get(api, { headers: this.headers }).pipe(
          map((res: Response) => {
            return res || {}
          }),
          catchError(this.handleError)
        )
      }
    
      // Error 
      handleError(error: HttpErrorResponse) {
        let msg = '';
        if (error.error instanceof ErrorEvent) {
          // client-side error
          msg = error.error.message;
        } else {
          // server-side error
          msg = `Error Code: ${error.status}\nMessage: ${error.message}`;
        }
        return throwError(msg);
      }
    }

*  The **signUp()** method stores the user name, email and password in mongoDB database.
 *  By taking the help of bcryptjs, we are storing the password securely in the database.
 *  The **signin()** method allows the user to access in the app using JSON web token generated by node server.
 *  We are getting JWT token from the API response and storing in the local storage, then in the **getToken()** method, we are accessing the token via local storage **getItem()** method.
 *  The **isLoggedIn** method returns true if the user is logged in else returns false.

## Set JWT Token with Angular 9 HttpInterceptor ##

In this part of the tutorial, we are going to set the JSON web token in the header using Angular 8/9 HttpInterceptor. To set the authorization header, first create the **authconfig.interceptor.ts** file in the shared folder.

import { Injectable } from "@angular/core";
    import { HttpInterceptor, HttpRequest, HttpHandler } from "@angular/common/http";
    import { AuthService } from "./auth.service";
    
    @Injectable()
    
    export class AuthInterceptor implements HttpInterceptor {
        constructor(private authService: AuthService) { }
    
        intercept(req: HttpRequest<any>, next: HttpHandler) {
            const authToken = this.authService.getToken();
            req = req.clone({
                setHeaders: {
                    Authorization: "Bearer " + authToken
                }
            });
            return next.handle(req);
        }
    }

Import the AuthService in and inject inside the constructor. In the **intercept()\{…\}** method call the **getToken()** method to get the JWT token then within the req.clone method set the Authorization header and call teh next.handle() method.

import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
    import { AuthInterceptor } from './shared/authconfig.interceptor';
    
    @NgModule({
      declarations: [...],
      imports: [HttpClientModule],
      providers: [
        {
          provide: HTTP_INTERCEPTORS,
          useClass: AuthInterceptor,
          multi: true
        }
      ],
      bootstrap: [...]
    })
    
    export class AppModule { }

Next, import the **HTTP\_INTERCEPTORS** in the **app.module.ts** file and set the HTTP\_INTERCEPTORS along with **AuthInterceptor** in `providers:[...]` array.

## Protect Routes with CanActivate ##

Run following command to set up [CanActivate interface class][CanActivate], It stops visitors to access certain urls in the Angular app. In our case we only want logged-in users to access the `/user-profile` URL.

ng g guard shared/auth

Next, add the following code in the **auth.guard.ts** file.

import { Injectable } from '@angular/core';
    import { ActivatedRouteSnapshot, RouterStateSnapshot, 
    UrlTree, CanActivate, Router } from '@angular/router';
    import { Observable } from 'rxjs';
    import { AuthService } from './../shared/auth.service';
    
    @Injectable({
      providedIn: 'root'
    })
    export class AuthGuard implements CanActivate {
    
      constructor(
        public authService: AuthService,
        public router: Router
      ) { }
    
      canActivate(
        next: ActivatedRouteSnapshot,
        state: RouterStateSnapshot): Observable<boolean> | Promise<boolean> | boolean {
        if (this.authService.isLoggedIn !== true) {
          window.alert("Access not allowed!");
          this.router.navigate(['log-in'])
        }
        return true;
      }
    }

Then, go to **app-routing.module.ts** file and import the AuthGuard interface class and inject the AuthGuard in the route as given below.

import { NgModule } from '@angular/core';
    import { Routes, RouterModule } from '@angular/router';
    
    import { SigninComponent } from './components/signin/signin.component';
    import { SignupComponent } from './components/signup/signup.component';
    import { UserProfileComponent } from './components/user-profile/user-profile.component';
    
    import { AuthGuard } from "./shared/auth.guard";
    
    
    const routes: Routes = [
      { path: '', redirectTo: '/log-in', pathMatch: 'full' },
      { path: 'log-in', component: SigninComponent },
      { path: 'sign-up', component: SignupComponent },
      { path: 'user-profile/:id', component: UserProfileComponent, canActivate: [AuthGuard] }
    ];
    
    @NgModule({
      imports: [RouterModule.forRoot(routes)],
      exports: [RouterModule]
    })
    
    export class AppRoutingModule { }

## 实现 Reactive Forms ##

Import `ReactiveFormsModule` and `FormsModule` in `app.module.ts`

imports: [
        ReactiveFormsModule,
        FormsModule,
        BrowserModule,
        AppRoutingModule,
        HttpClientModule,
      ],

## **在MEAN Stack App中实现用户注册** ##

**components/signup.component.ts** file add the following code

import {Component, OnInit} from '@angular/core';
    import {FormBuilder, FormGroup} from '@angular/forms';
    import {AuthService} from './../../shared/auth.service';
    import {Router} from '@angular/router';
    
    @Component({
      selector: 'app-signup',
      templateUrl: './signup.component.html',
      styleUrls: ['./signup.component.css']
    })
    export class SignupComponent implements OnInit {
      signupForm: FormGroup;
    
      constructor(
        public fb: FormBuilder,
        public authService: AuthService,
        public router: Router
      ) {
        this.signupForm = this.fb.group({
          name: [''],
          email: [''],
          mobile: [''],
          password: ['']
        });
      }
    
      ngOnInit() {
      }
    
      registerUser() {
        this.authService.signUp(this.signupForm.value).subscribe((res) => {
          if (res.result) {
            console.log(res);
            this.signupForm.reset();
            this.router.navigate(['log-in']);
          }
        });
      }
    }

**components/signup.component.html**

<div class="auth-wrapper">
        <form class="form-signin" [formGroup]="signupForm" (ngSubmit)="registerUser()">
            <h3 class="h3 mb-3 font-weight-normal text-center">Please sign up</h3>
            <div class="form-group">
                <label>Name</label>
                <input type="text" class="form-control" formControlName="name" placeholder="Enter name" required>
            </div>
            <div class="form-group">
                <label>Email address</label>
                <input type="email" class="form-control" formControlName="email" placeholder="Enter email" required>
            </div>
            <div class="form-group">
                <label>Password</label>
                <input type="password" class="form-control" formControlName="password" placeholder="Password" required>
            </div>
            <button type="submit" class="btn btn-block btn-primary">Sign up</button>
        </form>
    </div>

## **使用Angular处理MEAN Stack登录** ##

**components/signin.component.ts**

import {Component, OnInit} from '@angular/core';
    import {FormBuilder, FormGroup} from '@angular/forms';
    import {AuthService} from './../../shared/auth.service';
    import {Router} from '@angular/router';
    
    @Component({
      selector: 'app-signin',
      templateUrl: './signin.component.html',
      styleUrls: ['./signin.component.css']
    })
    
    export class SigninComponent implements OnInit {
      signinForm: FormGroup;
    
      constructor(
        public fb: FormBuilder,
        public authService: AuthService,
        public router: Router
      ) {
        this.signinForm = this.fb.group({
          email: [''],
          password: ['']
        });
      }
    
      ngOnInit() {
      }
    
      loginUser() {
        this.authService.signIn(this.signinForm.value);
      }
    }

**components/signin.component.html**

<div class="auth-wrapper">
        <form class="form-signin" [formGroup]="signinForm" (ngSubmit)="loginUser()">
            <h3 class="h3 mb-3 font-weight-normal text-center">Please sign in</h3>
            <div class="form-group">
                <label>Email</label>
                <input type="email" class="form-control" formControlName="email" placeholder="Enter email" required>
            </div>
            <div class="form-group">
                <label>Password</label>
                <input type="password" class="form-control" formControlName="password" placeholder="Password">
            </div>
            <button type="submit" class="btn btn-block btn-primary">Sign in</button>
        </form>
    </div>

## **在Angular 9 Auth App中获取用户个人资料** ##

**server / /middlewares/auth.js**文件中，`jwt.verify()`方法检查API请求，发现无效的令牌或JWT机密，则不呈现用户数据

**components / user-profile.component.ts**

import {Component, OnInit} from '@angular/core';
    import {ActivatedRoute} from '@angular/router';
    import {AuthService} from './../../shared/auth.service';
    import {User} from '../../shared/user';
    
    @Component({
      selector: 'app-user-profile',
      templateUrl: './user-profile.component.html',
      styleUrls: ['./user-profile.component.css']
    })
    
    export class UserProfileComponent implements OnInit {
      currentUser: User;
    
      constructor(
        public authService: AuthService,
        private actRoute: ActivatedRoute
      ) {
        const id = this.actRoute.snapshot.paramMap.get('id');
        this.authService.getUserProfile(id).subscribe(res => {
          this.currentUser = res.msg;
        });
      }
    
      ngOnInit() {
      }
    }

components / user-profile.component.html

<div class="container">
      <div class="row">
        <div class="inner-main">
          <h2 class="mb-4">User Profile</h2>
          <p><strong>Name:</strong> {
       {this.currentUser.name}}</p>
          <p><strong>Email:</strong> {
       {this.currentUser.email}}</p>
        </div>
      </div>
    </div>

## **在MEAN App中添加注销** ##

**app / app.component.ts**

import {Component} from '@angular/core';
    import {AuthService} from './shared/auth.service';
    
    @Component({
      selector: 'app-root',
      templateUrl: './app.component.html',
      styleUrls: ['./app.component.css']
    })
    
    export class AppComponent {
    
      constructor(public authService: AuthService) {
      }
    
      logout() {
        this.authService.doLogout();
      }
    }

**app / app.component.html**

<div class="container">
      <div
        class="d-flex flex-column flex-md-row align-items-center p-3 px-md-4 mb-3 bg-white border-bottom shadow-sm fixed-top">
        <h5 class="my-0 mr-md-auto font-weight-normal">Angular Mean Auth</h5>
        <nav class="my-2 my-md-0 mr-md-3">
          <a *ngIf="this.authService.isLoggedIn" class="p-2 text-dark">User Profile</a>
          <a *ngIf="!this.authService.isLoggedIn" class="p-2 text-dark" routerLinkActive="active" routerLink="/log-in">Sign
            in</a>
        </nav>
        <a *ngIf="!this.authService.isLoggedIn" class="btn btn-outline-primary" routerLinkActive="active"
           routerLinkActive="active" routerLink="/sign-up">Sign up</a>
        <button (click)="logout()" *ngIf="this.authService.isLoggedIn" type="button" class="btn btn-danger">Logout</button>
      </div>
    
      <router-outlet></router-outlet>
    </div>

![20191125230240775.png][]

[CanActivate]: https://www.positronx.io/protect-angular-2-routes-with-canactivate-guard-for-firebase-users/
[how to build secure _JWT_ Token-Based RESTful authentication API with Node_Express Js]: https://www.positronx.io/build-secure-jwt-token-based-authentication-api-with-node/
[Git Repo]: https://github.com/SinghDigamber/angular-meanstack-authentication
[Set up Angular 9 Project]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_01
[Clone Node Js Token-Based Auth REST API from GitHub]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_02
[Setting up HttpClient]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_03
[Creating User Authentication Service in Angular 9]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_04
[Set JWT Token with Angular 9 HttpInterceptor]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_05
[Protect Routes with CanActivate]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_06
[Implement Reactive Forms]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_07
[Implementing User Registration in MEAN Stack App]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_08
[Handling MEAN Stack Login with Angular 9]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_09
[Fetch User Profile in Angular 9 Auth App]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_10
[Conclusion]: https://www.positronx.io/angular-jwt-user-authentication-tutorial/#tc_6845_11
[http_localhost_4000_api]: http://localhost:4000/api
[Angular HttpClient service]: https://www.positronx.io/angular-8-httpclient-http-tutorial-build-consume-restful-api/
[20191125230240775.png]: https://img-blog.csdnimg.cn/20191125230240775.png