Learn Ionic 2 with Authentication by JWT ~ My Geeks

Auth0 team has a great post about How to secure your mobile app with JWT (Json Web Tokens). In this article, I want to modify its AuthService service with full functions. So you can reuse this code in any your project. Addition, I also show you how to navigate between pages after authenticated.

Step 1: start your project
#ionic start ionic-auth-jwt-sample blank --v2 --ts

Step 2: add angular2-jwt. I use version @0.1.12 because the latest version of angular2-jwt has problem with latest version of ionic 2 + angular:
#cd ionic-auth-jwt-sample
#npm install angular2-jwt@0.1.12

Step 3: install authenticate server
+Copy the source code from here
+Go to the folder copied, run the server
#npm install
#node server.js

Step 4: generate AuthService and modify its code
#ionic g provider AuthService

Then edit file app/providers/auth-service/auth-service.ts as below:

import {Injectable} from 'angular2/core';
import {Http, Headers} from 'angular2/http';
import {Storage, LocalStorage} from 'ionic-angular';
import {JwtHelper, tokenNotExpired} from 'angular2-jwt';
import 'rxjs/add/operator/map';
@Injectable()
export class AuthService {
    LOGIN_URL: string = "http://localhost:3001/sessions/create";
    SIGNUP_URL: string = "http://localhost:3001/users";
    contentHeader: Headers = new Headers({"Content-Type": "application/json"});
    local: Storage = new Storage(LocalStorage);
    jwtHelper: JwtHelper = new JwtHelper();
    user: string;
    error: string;
    constructor(private http: Http) {
        let token = localStorage.getItem('id_token');
        if (token) {
            this.user = this.jwtHelper.decodeToken(token).username;
        }
    }
    public authenticated() {
        return tokenNotExpired();
    }
    login(credentials) {
        return new Promise((resolve, reject) => {
            this.http.post(this.LOGIN_URL, JSON.stringify(credentials), { headers: this.contentHeader })
                .map(res => res.json())
                .subscribe(
                    data => {
                        this.authSuccess(data.id_token);
                        resolve(data)
                    },
                    err => {
                        this.error = err;
                        reject(err)
                    }
                );
        });
    }
    signup(credentials) {
        return new Promise((resolve, reject) => {
            this.http.post(this.SIGNUP_URL, JSON.stringify(credentials), { headers: this.contentHeader })
              .map(res => res.json())
              .subscribe(
                  data => {
                    this.authSuccess(data.id_token);
                    resolve(data)
                  },
                  err => {
                    this.error = err;
                    reject(err)
                  }
              );
        });
    }
    logout() {
        this.local.remove('id_token');
        this.user = null;
    }
    authSuccess(token) {
        this.error = null;
        this.local.set('id_token', token);
        this.user = this.jwtHelper.decodeToken(token).username;
    }
}

Step 5: generate LoginPage and WorkPage
#ionic g page Login
#ionic g page Work

Then edit file app/pages/login/login.ts as below:

import {Page, NavController} from 'ionic-angular';
import {AuthService} from '../../providers/auth-service/auth-service';
import {WorkPage} from '../work/work';
@Page({
templateUrl: 'build/pages/login/login.html',
})
export class LoginPage {
    authType: string = "login";

    constructor(private auth: AuthService, private nav: NavController) {
    }

    login(credentials) {
        this.auth.login(credentials).then(
          (success) => {
            this.nav.setRoot(WorkPage);
          },
          (err) => console.log(err)
        );
    }

    signup(credentials) {
        this.auth.signup(credentials).then(
          (success) => {
            this.nav.setRoot(WorkPage);
          },
          (err) => console.log(err)
        );
    }

}

Edit file app/pages/login/login.html as below:

<ion-navbar *navbar>
<ion-title>Login</ion-title>
</ion-navbar>
<ion-content class="login" *ngIf="!auth.authenticated()">

    <div padding>
      <ion-segment [(ngModel)]="authType">
        <ion-segment-button value="login">
          Login
        </ion-segment-button>
        <ion-segment-button value="signup">
          Signup
        </ion-segment-button>
      </ion-segment>
    </div>

    <div [ngSwitch]="authType">
      <form *ngSwitchWhen="'login'" #loginCreds="ngForm" (ngSubmit)="login(loginCreds.value)">
        <ion-item>
          <ion-label>Username</ion-label>
          <ion-input type="text" ngControl="username"></ion-input>
        </ion-item>

        <ion-item>
          <ion-label>Password</ion-label>
          <ion-input type="password" ngControl="password"></ion-input>
        </ion-item>

        <div padding>
          <button block type="submit">Login</button>
        </div>

      </form>
      <form *ngSwitchWhen="'signup'" #signupCreds="ngForm" (ngSubmit)="signup(signupCreds.value)">
        <ion-item>
          <ion-label>Username</ion-label>
          <ion-input type="text" ngControl="username"></ion-input>
        </ion-item>

        <ion-item>
          <ion-label>Password</ion-label>
          <ion-input type="password" ngControl="password"></ion-input>
        </ion-item>

        <div padding>
          <button block type="submit">Signup</button>
        </div>

      </form>
    </div>

    <div padding>
      <p *ngIf="error" class="error">{{ error._body }}</p>
    </div>

</ion-content>

Edit file app/pages/work/work.ts as below:

import {Page, NavController} from 'ionic-angular';
import {AuthService} from '../../providers/auth-service/auth-service';
import {LoginPage} from '../login/login';
@Page({
templateUrl: 'build/pages/work/work.html',
})
export class WorkPage {
constructor(private auth: AuthService, private nav: NavController) {}

logout() {
    this.auth.logout();
    this.nav.setRoot(LoginPage);
}
}

Edit file app/pages/work/work.html as below:

<ion-navbar *navbar>
<ion-title>Work</ion-title>
</ion-navbar>
<ion-content padding class="tools">
<div *ngIf="auth.authenticated()">
    <div padding>
      <h1>Welcome {{ auth.user }}! Let do your job then Logout.</h1>
      <button block (click)="logout()">Logout</button>
    </div>
</div>
</ion-content>

Step 6: edit file app/app.ts

import {App, Platform} from 'ionic-angular';
import {StatusBar} from 'ionic-native';
import {LoginPage} from './pages/login/login';
import {Http} from 'angular2/http';
import {AuthHttp, AuthConfig} from 'angular2-jwt';
import {provide} from 'angular2/core';
import {AuthService} from './providers/auth-service/auth-service';
@App({
template: '<ion-nav [root]="rootPage"></ion-nav>',
providers: [
      provide(AuthHttp, {
        useFactory: (http) => {
          return new AuthHttp(new AuthConfig, http);
        },
        deps: [Http]
      }),
      AuthService
    ],
config: {}
})
export class MyApp {
rootPage: any = LoginPage;
constructor(platform: Platform) {
    platform.ready().then(() => {
      StatusBar.styleDefault();
    });
}
}

Step 7: start the app and check.
#ionic serve

Below are my captured images: