Friday, 6 July, 2018 UTC

Vue Authentication And Route Handling Using Vue-router

Vue Authentication And Route Handling Using Vue-router

Summary

Vue is a progressive Javascript framework that makes building frontend applications easy. Coupled with vue-router, we can build high performance applications with complete dynamic routes. Vue-router is an efficient tool and can handle authentication in our Vue application seamlessly. In this tutorial, we will look at using vue-router to handle authentication and access control for different parts of our application.
Getting Started
To begin, install Vue cli and create a vue application with it:
$ npm install -g @vue/cli
$ npm install -g @vue/cli-init
$ vue init webpack vue-router-auth
Follow the setup prompt and complete the installation of this application. If you are not sure of an option, simply click the return key (enter key) to continue with the default option. When asked to install vue-router, accept the option, because we need vue-router for this application.
Setup Node.js Server
Next, we will setup a Node.js server that would handle authentication for us. For our Node.js server, we will use SQLite as the database of choice. Run the following command to install SQLite driver:
$ npm install --save sqlite3
Because we are dealing with passwords, we need a way to hash passwords. We will use bcrypt to hash all our passwords. Run the following command to install it:
$ npm install --save bcrypt
We also want a way to confirm the user’s we authenticate when they try to make a request to a secured part of our application. For this, we will use JWT. Run the following command to install the JWT package we will use:
$ npm install jsonwebtoken --save
To read json data we will send to our server, we need body-parser. Run the following command to install it:
$ npm install --save body-parser
Now that it’s all set, let us create a simple nodejs server that would handle user authentication. Create a new directory named server. This is where we will store everything we will use to make our node backend. In the server directory, create a file and save it as app.js. Add the following to it:
"use strict";
const express = require('express');
const cors = require('cors');
const DB = require('./db');
const config = require('./config');
const bcrypt = require('bcrypt');
const jwt = require('jsonwebtoken');
const bodyParser = require('body-parser');

const db = new DB("sqlitedb")
const app = express();
const router = express.Router();

router.use(bodyParser.urlencoded({ extended: false }));
router.use(bodyParser.json());

// CORS middleware
const allowCrossDomain = function(req, res, next) {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Methods', '*');
    res.header('Access-Control-Allow-Headers', '*');
    next();
}

app.use(allowCrossDomain)

router.post('/register', function(req, res) {
    db.insert([
        req.body.name,
        req.body.email,
        bcrypt.hashSync(req.body.password, 8)
    ],
    function (err) {
        if (err) return res.status(500).send("There was a problem registering the user.")
        db.selectByEmail(req.body.email, (err,user) => {
            if (err) return res.status(500).send("There was a problem getting user")
            let token = jwt.sign({ id: user.id }, config.secret, {expiresIn: 86400 // expires in 24 hours
            });
            res.status(200).send({ auth: true, token: token, user: user });
        }); 
    }); 
});

router.post('/register-admin', function(req, res) {
    db.insertAdmin([
        req.body.name,
        req.body.email,
        bcrypt.hashSync(req.body.password, 8),
        1
    ],
    function (err) {
        if (err) return res.status(500).send("There was a problem registering the user.")
        db.selectByEmail(req.body.email, (err,user) => {
            if (err) return res.status(500).send("There was a problem getting user")
            let token = jwt.sign({ id: user.id }, config.secret, { expiresIn: 86400 // expires in 24 hours
            });
            res.status(200).send({ auth: true, token: token, user: user });
        }); 
    }); 
});

router.get('/me', function(req, res) {
    let token = req.headers['x-access-token'];
    if (!token) return res.status(401).send({ auth: false, message: 'No token provided.' });

    jwt.verify(token, config.secret, function(err, decoded) {
        if (err) return res.status(500).send({ auth: false, message: 'Failed to authenticate token.' });
        res.status(200).send(decoded);
    });
});

router.post('/login', (req, res) => {
    db.selectByEmail(req.body.email, (err, user) => {
        if (err) return res.status(500).send('Error on the server.');
        if (!user) return res.status(404).send('No user found.');
        let passwordIsValid = bcrypt.compareSync(req.body.password, user.user_pass);
        if (!passwordIsValid) return res.status(401).send({ auth: false, token: null });
        let token = jwt.sign({ id: user.id }, config.secret, { expiresIn: 86400 // expires in 24 hours
        });
        res.status(200).send({ auth: true, token: token, user: user });
    });
})

app.use(router)

let port = process.env.PORT || 3000;

let server = app.listen(port, function() {
    console.log('Express server listening on port ' + port)
});
In the above file, we imported all the packages we need to setup the server. We did a little configuration to allow access for requests coming from outside our server. This is us basically handling CORS. If this is your first time dealing with CORS, just know that many developers in the past have spent hundreds of hours pulling their hair while wondering why a simple request could not work. It was a sad time 😢 😭 .
We then went on to define the different routes for our server, and what our server should do when a user makes a request to the route. Finally, we created a server on port: 3000 or any dynamically generated port by our system (heroku generates dynamic ports).
If you find any of the above confusing, you can take an introductory course on Node.js
Then, create another file config.js in the same directory and add the following to it:
module.exports = {
    'secret': 'supersecret'
};
Finally, create another file db.js and add the following to it:
"use strict";
const sqlite3 = require('sqlite3').verbose();

class Db {
    constructor(file) {
        this.db = new sqlite3.Database(file);
        this.createTable()
    }

    createTable() {
        const sql = `
            CREATE TABLE IF NOT EXISTS user (
                id integer PRIMARY KEY, 
                name text, 
                email text UNIQUE, 
                user_pass text)`
        return this.db.run(sql);
    }

    selectByEmail(email, callback) {
        return this.db.get(
            `SELECT * FROM user WHERE email = ?`,
            [email],function(err,row){
                callback(err,row)
            })
    }

    insertAdmin(user, callback) {
        return this.db.run(
            'INSERT INTO user (name,email,user_pass,is_admin) VALUES (?,?,?,?)',
            user, (err) => {
                callback(err)
            })
    }

    selectAll(callback) {
        return this.db.all(`SELECT * FROM user`, function(err,rows){
            callback(err,rows)
        })
    }

    insert(user, callback) {
        return this.db.run(
            'INSERT INTO user (name,email,user_pass) VALUES (?,?,?)',
            user, (err) => {
                callback(err)
            })
    }
}

module.exports = Db
We created a class for our database to abstract the basic functions we need. You may want to use more generic and reusable methods here for database operations and likely use a promise to make it more efficient. This will allow you have a repository you can use with all other classes you define (especially if your application uses MVC architecture and has controllers).
All done and looking good, let’s make the vue application now.
Updating The Vue-router File
The vue-router file can be found in ./src/router/ directory. In the index.js file, we will define all the routes we want our application to have. This is different from what we did with our server and should not be confused.
Open the file and add the following:
import Vue from 'vue'
import Router from 'vue-router'
import HelloWorld from '@/components/HelloWorld'
import Login from '@/components/Login'
import Register from '@/components/Register'
import UserBoard from '@/components/UserBoard'
import Admin from '@/components/Admin'

Vue.use(Router)

let router = new Router({
    mode: 'history',
    routes: [
        {
            path: '/',
            name: 'HelloWorld',
            component: HelloWorld
        },
        {
            path: '/login',
            name: 'login',
            component: Login,
            meta: { 
                guest: true
            }
        },
        {
            path: '/register',
            name: 'register',
            component: Register,
            meta: { 
                guest: true
            }
        },
        {
            path: '/dashboard',
            name: 'userboard',
            component: UserBoard,
            meta: { 
                requiresAuth: true
            }
        },
        {
            path: '/admin',
            name: 'admin',
            component: Admin,
            meta: { 
                requiresAuth: true,
                is_admin : true
            }
        },
    ]
})

router.beforeEach((to, from, next) => {
    if(to.matched.some(record => record.meta.requiresAuth)) {
        if (localStorage.getItem('jwt') == null) {
            next({
                path: '/login',
                params: { nextUrl: to.fullPath }
            })
        } else {
            let user = JSON.parse(localStorage.getItem('user'))
            if(to.matched.some(record => record.meta.is_admin)) {
                if(user.is_admin == 1){
                    next()
                }
                else{
                    next({ name: 'userboard'})
                }
            }else {
                next()
            }
        }
    } else if(to.matched.some(record => record.meta.guest)) {
        if(localStorage.getItem('jwt') == null){
            next()
        }
        else{
            next({ name: 'userboard'})
        }
    }else {
        next() 
    }
})

export default router
What happens in that file is pretty straight forward. At the top, we imported the packages and components we need for the router. Then, we defined the router and the routes for our application. Finally, we defined the rules our router uses to render components.
If you look at the route definitions, you would notice some routes have a meta property. This meta property enables us to define additional conditions to check before either allowing a user to see a page/mount a component or redirecting a user to a different page. In this router definition, we used a meta property with values requiresAuth, is_admin and guest.
Vue-router has a beforeEach method that is called before each route is processed. This is where we can define our checking condition and restrict user access. The method takes three parameters — to, from and next. to is where the user wishes to go, from is where the user is coming from, next is a callback function that continues the processing of the user request. Our check is on the to object.
We check a few things:
  • if route requiresAuth, check for a jwt token showing the user is logged in.
  • if route requiresAuth and is only for admin users, check for auth and check if the user is an admin
  • if route requires guest, check if the user is logged in
We redirect the user based on what we are checking for. We use the name of the route to redirect, so check to be sure you are using this for your application.
IMPORTANT: Always ensure you have next() called at the end of every condition you are checking. This is to prevent your application from failing in the event that there is a condition you forgot to check.
Define Some Components
To test out what we have built, let’s define a few components. In the ./src/components/ directory, open the HelloWorld.vue file and add the following:
<template>
    <div class="hello">
        <h1>This is homepage</h1>
        <h2>{{msg}}</h2>
    </div>
</template>

<script>
    export default {
        data () {
            return {
                msg: 'Hello World!'
            }
        }
    }
</script>
    <!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
    h1, h2 {
        font-weight: normal;
    }
    ul {
        list-style-type: none;
        padding: 0;
    }
    li {
        display: inline-block;
        margin: 0 10px;
    }
    a {
        color: #42b983;
    }
</style>
Create a new file Login.vue in the same directory and add the following:
<template>
    <div>
        <h4>Login</h4>
        <form>
            <label for="email" >E-Mail Address</label>
            <div>
                <input id="email" type="email" v-model="email" required autofocus>
            </div>
            <div>
                <label for="password" >Password</label>
                <div>
                    <input id="password" type="password" v-model="password" required>
                </div>
            </div>
            <div>
                <button type="submit" @click="handleSubmit">
                    Login
                </button>
            </div>
        </form>
    </div>
</template>
<script>
    export default {
        data(){
            return {
                email : "",
                password : ""
            }
        },
        methods : {
            handleSubmit(e){
                e.preventDefault()
                if (this.password.length > 0) {
                    this.$http.post('http://localhost:3000/login', {
                        email: this.email,
                        password: this.password
                    })
                    .then(response => {
                        let is_admin = response.data.user.is_admin
                        localStorage.setItem('user',JSON.stringify(response.data.user))
                        localStorage.setItem('jwt',response.data.token)

                        if (localStorage.getItem('jwt') != null){
                            this.$emit('loggedIn')
                            if(this.$route.params.nextUrl != null){
                                this.$router.push(this.$route.params.nextUrl)
                            }
                            else {
                                if(is_admin== 1){
                                    this.$router.push('admin')
                                }
                                else {
                                    this.$router.push('dashboard')
                                }
                            }
                        }
                    })
                    .catch(function (error) {
                        console.error(error.response);
                    });
                }
            }
        }
    }
</script>
In the Login.vue file, we have defined the login component. We defined a method to handle user submission and log the user in. If you are not familiar with composing vue components, you can take this Getting Started With Vue course.
Next, create a Register.vue file and add the following to it:
<template>
    <div>
        <h4>Register</h4>
        <form>
            <label for="name">Name</label>
            <div>
                <input id="name" type="text" v-model="name" required autofocus>
            </div>

            <label for="email" >E-Mail Address</label>
            <div>
                <input id="email" type="email" v-model="email" required>
            </div>

            <label for="password">Password</label>
            <div>
                <input id="password" type="password" v-model="password" required>
            </div>

            <label for="password-confirm">Confirm Password</label>
            <div>
                <input id="password-confirm" type="password" v-model="password_confirmation" required>
            </div>

            <label for="password-confirm">Is this an administrator account?</label>
            <div>
                <select v-model="is_admin">
                    <option value=1>Yes</option>
                    <option value=0>No</option>
                </select>
            </div>

            <div>
                <button type="submit" @click="handleSubmit">
                    Register
                </button>
            </div>
        </form>
    </div>
</template>

<script>
    export default {
        props : ["nextUrl"],
        data(){
            return {
                name : "",
                email : "",
                password : "",
                password_confirmation : "",
                is_admin : null
            }
        },
        methods : {
            handleSubmit(e) {
                e.preventDefault()

                if (this.password === this.password_confirmation && this.password.length > 0)
                {
                    let url = "http://localhost:3000/register"
                    if(this.is_admin != null || this.is_admin == 1) url = "http://localhost:3000/register-admin"
                    this.$http.post(url, {
                        name: this.name,
                        email: this.email,
                        password: this.password,
                        is_admin: this.is_admin
                    })
                    .then(response => {
                        localStorage.setItem('user',JSON.stringify(response.data.user))
                        localStorage.setItem('jwt',response.data.token)

                        if (localStorage.getItem('jwt') != null){
                            this.$emit('loggedIn')
                            if(this.$route.params.nextUrl != null){
                                this.$router.push(this.$route.params.nextUrl)
                            }
                            else{
                                this.$router.push('/')
                            }
                        }
                    })
                    .catch(error => {
                        console.error(error);
                    });
                } else {
                    this.password = ""
                    this.passwordConfirm = ""

                    return alert("Passwords do not match")
                }
            }
        }
    }
</script>
This is similar in structure to the Login.vue file. It creates the register component and accompanying method to handle user submission of the registration form.
Now, create the file Admin.vue and add the following:
<template>
    <div class="hello">
        <h1>Welcome to administrator page</h1>
        <h2>{{msg}}</h2>
    </div>
</template>

<script>
    export default {
        data () {
            return {
                msg: 'The superheros'
            }
        }
    }
</script>
<style scoped>
    h1, h2 {
        font-weight: normal;
    }
    ul {
        list-style-type: none;
        padding: 0;
    }
    li {
        display: inline-block;
        margin: 0 10px;
    }
    a {
        color: #42b983;
    }
</style>
This is the component we will mount when a user visits the admin page.
Finally, create the file UserBoard.vue and add the following:
<template>
    <div class="hello">
        <h1>Welcome to regular users page</h1>
        <h2>{{msg}}</h2>
    </div>
</template>

<script>
    export default {
        data () {
            return {
                msg: 'The commoners'
            }
        }
    }
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
    h1, h2 {
        font-weight: normal;
    }
    ul {
        list-style-type: none;
        padding: 0;
    }
    li {
        display: inline-block;
        margin: 0 10px;
    }
    a {
        color: #42b983;
    }
</style>
This is the file we will see when a user visits the dashboard page.
And that’s it for components.
Setting Up Axios Globally
For all our server requests, we will use axios. Axios is a promise based HTTP client for the browser and node.js. Run the following command to install axios:
$ npm install --save axios
To make it accessible across all our components, open the ./src/main.js file and add the following:
import Vue from 'vue'
import App from './App'
import router from './router'
import Axios from 'axios'

Vue.prototype.$http = Axios;

Vue.config.productionTip = false

new Vue({
    el: '#app',
    router,
    components: { App },
    template: '<App/>'
})
By defining Vue.prototype.$http = Axios we have modified the vue engine and added axios. We can now use axios in all our components like this.$http.
Running The Application
Now that we are done with the application, we need to build all our assets and run it. Because we have a node js server along with our vue application, we will be both of them for our application to work.
Let’s add a script that will help us run our node server. Open the package.json file and add the following:
[...]
"scripts": {
    "dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
    "start": "npm run dev",
    "server": "node server/app",
    "build": "node build/build.js"
  },
[...]
We added the server script to help us start up the node server. Now, run the following command to start the server:
$ npm run server
You should see something like this:
Then create another terminal instance and run the vue app like this:
$ npm run dev
This will build all the assets and st art the application. You can open the link it shows you to see the application
Conclusion
In this guide, we have seen how to use vue-router to define checks on our routes and prevent users from accessing certain routes. We also saw how to redirect users to different parts of our application based on the authentication state. We also built a mini server with Node.js to handle user authentication.
What we did is an example of how access control is designed in frameworks like Laravel. You can checkout out vue-router and see what other cool things you can do with it.

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