This integration guide will walk you through setting up and managing authentication and authorization in your Vue.js apps using Auth0.

Get Your Application Keys

When you signed up for Auth0, you were invited to create a new client.

There are some details about this client that your application needs to know about to properly communicate with Auth0, including your Client ID and Domain. You can retrieve these values from the settings area for your client in the Auth0 dashboard.

Please note that if you download the samples available for this tutorial, these keys will be pre-populated for you. If you have created more than one client in your account, the sample will come with the values for your Default App.

Configure Callback URLs

A callback URL is a URL in your application where Auth0 redirects to after the user has authenticated. You need to whitelist a callback URL for your app in the Callback URLs field in your Client Settings. If no callback URLs are set, a mismatch error will be displayed when a user logs in.

If you are following along with the downloadable sample projects for this tutorial directly, the Callback URL should be set to

http://localhost:8080/callback

Install auth0.js

Integrating Auth0 in your application requires the auth0.js library. Install it using npm or yarn.

# installation with npm
npm install --save auth0-js

# installation with yarn
yarn add auth0-js

Once auth0.js is installed, add it to your build system or bring it in to your project with a script tag.

<script type="text/javascript" src="node_modules/auth0-js/build/auth0.js"></script>

If you don't want to use a package manager, auth0.js can also be retrieved from Auth0's CDN.

<script src="https://cdn.auth0.com/js/auth0/8.7/auth0.min.js"></script>

Add Authentication with Auth0

The first step in adding authentication to your Vue.js application is to provide a way for your users to log in. The fastest, most secure, and most feature-rich way to do this with Auth0 is to use the hosted login page.

When authentication is successful, three items will be returned which can all be used at some point in your application: an access_token, an id_token, and the number of seconds until the access_token expires.

Create an Authentication Service

The best way to manage and coordinate the tasks necessary for user authentication is to create a reusable service. With the service in place, you'll be able to call its methods throughout your application. The name for it is at your discretion, but in these examples it will be called AuthService and the filename will be AuthService.js. An instance of the WebAuth object from auth0.js can be created in the service.

Create a service and instantiate auth0.WebAuth. Provide a method called login which calls the authorize from auth0.js.

// src/Auth/AuthService.js

import auth0 from 'auth0-js'

export default class AuthService {

  constructor () {
    this.login = this.login.bind(this)
  }

  auth0 = new auth0.WebAuth({
    domain: 'YOUR_AUTH0_DOMAIN',
    clientID: 'YOUR_CLIENT_ID',
    redirectUri: 'http://localhost:8080/callback',
    audience: 'https://YOUR_AUTH0_DOMAIN/userinfo',
    responseType: 'token id_token',
    scope: 'openid'
  })

  login () {
    this.auth0.authorize()
  }
}

Finish Out the Service

Add some additional methods to the Auth service to fully handle authentication in the app.

// src/Auth/AuthService.js

import auth0 from 'auth0-js'
import EventEmitter from 'EventEmitter'
import router from './../router'

export default class AuthService {

  authenticated = this.isAuthenticated()
  authNotifier = new EventEmitter()

  constructor () {
    this.login = this.login.bind(this)
    this.setSession = this.setSession.bind(this)
    this.logout = this.logout.bind(this)
    this.isAuthenticated = this.isAuthenticated.bind(this)
  }

  // ...
  handleAuthentication () {
    this.auth0.parseHash((err, authResult) => {
      if (authResult && authResult.accessToken && authResult.idToken) {
        this.setSession(authResult)
        router.replace('home')
      } else if (err) {
        router.replace('home')
        console.log(err)
      }
    })
  }

  setSession (authResult) {
    // Set the time that the access token will expire at
    let expiresAt = JSON.stringify(
      authResult.expiresIn * 1000 + new Date().getTime()
    )
    localStorage.setItem('access_token', authResult.accessToken)
    localStorage.setItem('id_token', authResult.idToken)
    localStorage.setItem('expires_at', expiresAt)
    this.authNotifier.emit('authChange', { authenticated: true })
  }

  logout () {
    // Clear access token and ID token from local storage
    localStorage.removeItem('access_token')
    localStorage.removeItem('id_token')
    localStorage.removeItem('expires_at')
    this.userProfile = null
    this.authNotifier.emit('authChange', false)
    // navigate to the home route
    router.replace('home')
  }

  isAuthenticated () {
    // Check whether the current time is past the
    // access token's expiry time
    let expiresAt = JSON.parse(localStorage.getItem('expires_at'))
    return new Date().getTime() < expiresAt
  }
}

The service now includes several other methods for handling authentication.

• handleAuthentication - looks for an authentication result in the URL hash and processes it with the parseHash method from auth0.js
• setSession - sets the user's access_token, id_token, and a time at which the access_token will expire
• logout - removes the user's tokens from browser storage
• isAuthenticated - checks whether the expiry time for the access_token has passed

About the Authentication Service

The first noteworthy thing happening in this service is that an instance of auth0.WebAuth is created. The options object passed to it includes configuration for your client and domain, a response type to indicate you would like to receive an access_token and id_token after authentication, and an audience and scope which specify that authentication should be OIDC conformant. Also specified is the location that users should be returned to after authentication is complete. In this case, that's a route of /callback, which will be implemented later.

When a user successfully authenticates at Auth0's hosted login page and is redirected back to your application, there will be a hash fragment in the URL containing their authentication information. Contained within will be an access_token, an id_token and an expires_in value. These values are extracted from the URL using the parseHash method from auth0.js and are then saved into local storage with the setSession method. This method also calculates the time at which the access_token will expire using the expires_in value from the hash.

Authentication using JSON Web Tokens is stateless by nature, meaning that there is no information about the user's session stored on your server. In this way, setting up a session for the user on the client side is simply a matter of saving the access_token, id_token, and a time that the access_token expires at in browser storage. Conversely, logging the user out only requires that these items be removed from storage. These examples use local storage to save the tokens and the expiry time, but you may also use session storage or cookies if you wish.

The application needs some way to make decisions about showing or hiding UI elements and restricting routing based on whether or not the user can be considered "authenticated". Once again, since JWT authentication is stateless, there is no real way to say whether the user is authenticated in any traditional sense, but there are clues that can be used. The best clue to go with is whether or not the access_token is expired. If it is expired, anything meaningful that the user could do with it--such as a call to your API for protected resources--will not work. It's at this point that the user would need to reauthenticate and get a new token. The isAuthenticated method checks whether the expiry time for the access_token has passed or not so that the above-mentioned decisions can be made.

Provide a Login Control

Provide a component with controls for the user to log in and log out.

// src/App.vue

<template>
  <div>
    <nav class="navbar navbar-default">
      <div class="container-fluid">
        <div class="navbar-header">
          <a class="navbar-brand" href="#">Auth0 - Vue</a>

          <router-link :to="'/'"
            class="btn btn-primary btn-margin">
              Home
          </router-link>

          <button
            class="btn btn-primary btn-margin"
            v-if="!authenticated"
            @click="login()">
              Log In
          </button>

          <button
            class="btn btn-primary btn-margin"
            v-if="authenticated"
            @click="logout()">
              Log Out
          </button>

        </div>
      </div>
    </nav>

    <div class="container">
      <router-view 
        :auth="auth" 
        :authenticated="authenticated">
      </router-view>
    </div>
  </div>
</template>

<script>

import AuthService from './auth/AuthService'

const auth = new AuthService()

const { login, logout, authenticated, authNotifier } = auth

export default {
  name: 'app',
  data () {
    authNotifier.on('authChange', authState => {
      this.authenticated = authState.authenticated
    })
    return {
      auth,
      authenticated
    }
  },
  methods: {
    login,
    logout
  }
}
</script>

<style>
@import '../node_modules/bootstrap/dist/css/bootstrap.css';
</style>

The @click events on the Log In and Log Out buttons make the appropriate calls to the AuthService to allow the user to log in and log out. Notice that these buttons are conditionally hidden and shown depending on whether or not the user is currently authenticated.

When the Log In button is clicked, the user will be redirected to Auth0's hosted login page.

Add a Callback Component

Using Auth0's hosted login page means that users are taken away from your application to a page hosted by Auth0. After they successfully authenticate, they are returned to your application where a client-side session is set for them.

You can choose to have users return to any URL in your application that you like; however, it is recommended that you create a dedicated callback route to serve as a central location that the user will be returned to upon successful authentication. Having a single callback route is beneficial for two main reasons:

• It prevents the need to whitelist multiple (and sometimes unknown) callback URLs
• It serves as a place to show a loading indicator while your application sets the user's client-side session

When a user authenticates at Auth0's hosted login page and is then redirected back to your application, their authentication information will be contained in a URL hash fragment. The handleAuthentication method in the AuthService is responsbile for processing the hash.

Create a component named CallbackComponent and populate it with a loading indicator. The component should also call handleAuthentication from the AuthService.

// src/components/Callback.vue

<template>
  <div class="spinner">
    <img src="../assets/loading.svg" alt="loading"/>
  </div>
</template>

<script>
  export default {
    name: 'callback',
    props: ['auth'],
    data () {
      this.auth.handleAuthentication()
      return {}
    }
  }
</script>

After authentication, users will be taken to the /callback route for a brief time where they will be shown a loading indicator. During this time, their client-side session will be set, after which they will be redirected to the /home route.

Embedded Login

Auth0's hosted login page provides the fastest, most secure, and most feature-rich way to implement authentication in your app. If required, the Lock widget can also be embedded directly into your application, but certain features such as single sign-on won't be accessible. It is highly recommended that you use the hosted login page (as covered in this tutorial), but if you wish to embed the Lock widget directly in your application, follow the Embedded Login sample.