Tập tành chọt Node.js Express: JWT example

In this tutorial, we’re gonna build a Node.js Express Rest API example that supports Token Based Authentication with JWT (JSONWebToken). You’ll know:

• Appropriate Flow for User Signup & User Login with JWT Authentication
• Node.js Express Architecture with CORS, Authentication & Authorization middlewares & Sequelize
• How to configure Express routes to work with JWT
• How to define Data Models and association for Authentication and Authorization
• Way to use Sequelize to interact with MySQL Database

Token Based Authentication

Comparing with Session-based Authentication that need to store Session on Cookie, the big advantage of Token-based Authentication is that we store the JSON Web Token (JWT) on Client side: Local Storage for Browser, Keychain for IOS and SharedPreferences for Android… So we don’t need to build another backend project that supports Native Apps or an additional Authentication module for Native App users.

There are three important parts of a JWT: Header, Payload, Signature. Together they are combined to a standard structure: header.payload.signature.

The Client typically attaches JWT in Authorization header with Bearer prefix:

Authorization: Bearer [header].[payload].[signature]

Or only in x-access-token header:

x-access-token: [header].[payload].[signature]

Overview of Node.js Express JWT Authentication example

We will build a Node.js Express application in that:

1. User can signup new account, or login with username & password.
2. By User’s role (admin, moderator, user), we authorize the User to access resources

This is our Node.js application demo running with MySQL database and test Rest Apis with Postman.

These are APIs that we need to provide:

Methods	Urls	Actions
POST	/api/auth/signup	signup new account
POST	/api/auth/signin	login an account
GET	/api/test/all	retrieve public content
GET	/api/test/user	access User’s content
GET	/api/test/mod	access Moderator’s content
GET	/api/test/admin	access Admin’s content

Flow for Signup & Login with JWT Authentication

The diagram shows flow of User Registration, User Login and Authorization process.

A legal JWT must be added to HTTP x-access-token Header if Client accesses protected resources.

You will need to implement Refresh Token:

Node.js Express Architecture with Authentication & Authorization

You can have an overview of our Node.js Express App with the diagram below:

Via Express routes, HTTP request that matches a route will be checked by CORS Middleware before coming to Security layer.

Security layer includes:

• JWT Authentication Middleware: verify SignUp, verify token
• Authorization Middleware: check User’s roles with record in database

If these middlewares throw any error, a message will be sent as HTTP response.

Controllers interact with MySQL Database via Sequelize and send HTTP response (token, user information, data based on roles…) to client.

Technology

• Express 4.17.1
• bcryptjs 2.4.3
• jsonwebtoken 8.5.1
• Sequelize 5.21.3
• MySQL

Project Structure

This is directory structure for our Node.js Express application:

– config

• configure MySQL database & Sequelize
• configure Auth Key

– routes

• auth.routes.js: POST signup & signin
• user.routes.js: GET public & protected resources

– middlewares

• verifySignUp.js: check duplicate Username or Email
• authJwt.js: verify Token, check User roles in database

– controllers

• auth.controller.js: handle signup & signin actions
• user.controller.js: return public & protected content

– models for Sequelize Models

• user.model.js
• role.model.js

– server.js: import and initialize necessary modules and routes, listen for connections.

Create Node.js App

First, we create a folder for our project:

$ mkdir node-js-jwt-auth
$ cd node-js-jwt-auth

Then we initialize the Node.js App with a package.json file:

npm init
name: (node-js-jwt-auth) 
version: (1.0.0) 
description: Node.js Demo for JWT Authentication
entry point: (index.js) server.js
test command: 
git repository: 
keywords: node.js, express, jwt, authentication, mysql
author: bezkoder
license: (ISC)
Is this ok? (yes) yes

We need to install necessary modules: express, cors, sequelize, mysql2, jsonwebtoken and bcryptjs.
Run the command:

npm install express sequelize mysql2 cors jsonwebtoken bcryptjs --save

The package.json file now looks like this:

{
  "name": "node-js-jwt-auth",
  "version": "1.0.0",
  "description": "Node.js Demo for JWT Authentication",
  "main": "server.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [
    "node.js",
    "jwt",
    "authentication",
    "express",
    "mysql"
  ],
  "author": "bezkoder",
  "license": "ISC",
  "dependencies": {
    "bcryptjs": "^2.4.3",
    "cors": "^2.8.5",
    "express": "^4.17.1",
    "jsonwebtoken": "^8.5.1",
    "mysql2": "^2.1.0",
    "sequelize": "^5.21.3"
  }
}

Setup Express web server

In the root folder, let’s create a new server.js file:

const express = require("express");
const cors = require("cors");
const app = express();
var corsOptions = {
  origin: "http://localhost:8081"
};
app.use(cors(corsOptions));
// parse requests of content-type - application/json
app.use(express.json());
// parse requests of content-type - application/x-www-form-urlencoded
app.use(express.urlencoded({ extended: true }));
// simple route
app.get("/", (req, res) => {
  res.json({ message: "Welcome to bezkoder application." });
});
// set port, listen for requests
const PORT = process.env.PORT || 8080;
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}.`);
});

Let me explain what we’ve just done:
– import express and cors modules:

• Express is for building the Rest apis
• cors provides Express middleware to enable CORS

– create an Express app, then add request body parser and cors middlewares using app.use() method. Notice that we set origin: http://localhost:8081.
– define a GET route which is simple for test.
– listen on port 8080 for incoming requests.

Now let’s run the app with command: node server.js.

Open your browser with url http://localhost:8080/, you will see:

Configure MySQL database & Sequelize

In the app folder, create config folder for configuration with db.config.js file like this:

module.exports = {
  HOST: "localhost",
  USER: "root",
  PASSWORD: "123456",
  DB: "testdb",
  dialect: "mysql",
  pool: {
    max: 5,
    min: 0,
    acquire: 30000,
    idle: 10000
  }
};

First five parameters are for MySQL connection.
pool is optional, it will be used for Sequelize connection pool configuration:

• max: maximum number of connection in pool
• min: minimum number of connection in pool
• idle: maximum time, in milliseconds, that a connection can be idle before being released
• acquire: maximum time, in milliseconds, that pool will try to get connection before throwing error

Define the Sequelize Model

In models folder, create User and Role data model as following code:

models/user.model.js

module.exports = (sequelize, Sequelize) => {
  const User = sequelize.define("users", {
    username: {
      type: Sequelize.STRING
    },
    email: {
      type: Sequelize.STRING
    },
    password: {
      type: Sequelize.STRING
    }
  });
  return User;
};

models/role.model.js

module.exports = (sequelize, Sequelize) => {
  const Role = sequelize.define("roles", {
    id: {
      type: Sequelize.INTEGER,
      primaryKey: true
    },
    name: {
      type: Sequelize.STRING
    }
  });
  return Role;
};

These Sequelize Models represents users & roles table in MySQL database.

After initializing Sequelize, we don’t need to write CRUD functions, Sequelize supports all of them:

• create a new User: create(object)
• find a User by id: findByPk(id)
• find a User by email: findOne({ where: { email: ... } })
• get all Users: findAll()
• find all Users by username: findAll({ where: { username: ... } })

These functions will be used in our Controllers and Middlewares.

Initialize Sequelize

Now create app/models/index.js with content like this:

const config = require("../config/db.config.js");
const Sequelize = require("sequelize");
const sequelize = new Sequelize(
  config.DB,
  config.USER,
  config.PASSWORD,
  {
    host: config.HOST,
    dialect: config.dialect,
    operatorsAliases: false,
    pool: {
      max: config.pool.max,
      min: config.pool.min,
      acquire: config.pool.acquire,
      idle: config.pool.idle
    }
  }
);
const db = {};
db.Sequelize = Sequelize;
db.sequelize = sequelize;
db.user = require("../models/user.model.js")(sequelize, Sequelize);
db.role = require("../models/role.model.js")(sequelize, Sequelize);
db.role.belongsToMany(db.user, {
  through: "user_roles",
  foreignKey: "roleId",
  otherKey: "userId"
});
db.user.belongsToMany(db.role, {
  through: "user_roles",
  foreignKey: "userId",
  otherKey: "roleId"
});
db.ROLES = ["user", "admin", "moderator"];
module.exports = db;

The association between Users and Roles is Many-to-Many relationship:

– One User can have several Roles.

– One Role can be taken on by many Users.

We use User.belongsToMany(Role) to indicate that the user model can belong to many Roles and vice versa.

With through, foreignKey, otherKey, we’re gonna have a new table user_roles as connection between users and roles table via their primary key as foreign keys.

Don’t forget to call sync() method in server.js.

...
const app = express();
app.use(...);
const db = require("./app/models");
const Role = db.role;
db.sequelize.sync({force: true}).then(() => {
  console.log('Drop and Resync Db');
  initial();
});
...
function initial() {
  Role.create({
    id: 1,
    name: "user"
  });
 
  Role.create({
    id: 2,
    name: "moderator"
  });
 
  Role.create({
    id: 3,
    name: "admin"
  });
}

initial() function helps us to create 3 rows in database.

In development, you may need to drop existing tables and re-sync database. So you can use force: true as code above.

For production, just insert these rows manually and use sync() without parameters to avoid dropping data:

...
const app = express();
app.use(...);
const db = require("./app/models");
db.sequelize.sync();
...

Configure Auth Key

jsonwebtoken functions such as verify() or sign() use algorithm that needs a secret key (as String) to encode and decode token.

In the app/config folder, create auth.config.js file with following code:

module.exports = {
  secret: "bezkoder-secret-key"
};

You can create your own secret String.

Create Middleware functions

To verify a Signup action, we need 2 functions:

– check if username or email is duplicate or not

– check if roles in the request is existed or not

middleware/verifySignUp.js

const db = require("../models");
const ROLES = db.ROLES;
const User = db.user;
checkDuplicateUsernameOrEmail = (req, res, next) => {
  // Username
  User.findOne({
    where: {
      username: req.body.username
    }
  }).then(user => {
    if (user) {
      res.status(400).send({
        message: "Failed! Username is already in use!"
      });
      return;
    }
    // Email
    User.findOne({
      where: {
        email: req.body.email
      }
    }).then(user => {
      if (user) {
        res.status(400).send({
          message: "Failed! Email is already in use!"
        });
        return;
      }
      next();
    });
  });
};
checkRolesExisted = (req, res, next) => {
  if (req.body.roles) {
    for (let i = 0; i < req.body.roles.length; i++) {
      if (!ROLES.includes(req.body.roles[i])) {
        res.status(400).send({
          message: "Failed! Role does not exist = " + req.body.roles[i]
        });
        return;
      }
    }
  }
  
  next();
};
const verifySignUp = {
  checkDuplicateUsernameOrEmail: checkDuplicateUsernameOrEmail,
  checkRolesExisted: checkRolesExisted
};
module.exports = verifySignUp;

To process Authentication & Authorization, we have these functions:

- check if token is provided, legal or not. We get token from x-access-token of HTTP headers, then use jsonwebtoken's verify() function.

- check if roles of the user contains required role or not.

middleware/authJwt.js

const jwt = require("jsonwebtoken");
const config = require("../config/auth.config.js");
const db = require("../models");
const User = db.user;
verifyToken = (req, res, next) => {
  let token = req.headers["x-access-token"];
  if (!token) {
    return res.status(403).send({
      message: "No token provided!"
    });
  }
  jwt.verify(token, config.secret, (err, decoded) => {
    if (err) {
      return res.status(401).send({
        message: "Unauthorized!"
      });
    }
    req.userId = decoded.id;
    next();
  });
};
isAdmin = (req, res, next) => {
  User.findByPk(req.userId).then(user => {
    user.getRoles().then(roles => {
      for (let i = 0; i < roles.length; i++) {
        if (roles[i].name === "admin") {
          next();
          return;
        }
      }
      res.status(403).send({
        message: "Require Admin Role!"
      });
      return;
    });
  });
};
isModerator = (req, res, next) => {
  User.findByPk(req.userId).then(user => {
    user.getRoles().then(roles => {
      for (let i = 0; i < roles.length; i++) {
        if (roles[i].name === "moderator") {
          next();
          return;
        }
      }
      res.status(403).send({
        message: "Require Moderator Role!"
      });
    });
  });
};
isModeratorOrAdmin = (req, res, next) => {
  User.findByPk(req.userId).then(user => {
    user.getRoles().then(roles => {
      for (let i = 0; i < roles.length; i++) {
        if (roles[i].name === "moderator") {
          next();
          return;
        }
        if (roles[i].name === "admin") {
          next();
          return;
        }
      }
      res.status(403).send({
        message: "Require Moderator or Admin Role!"
      });
    });
  });
};
const authJwt = {
  verifyToken: verifyToken,
  isAdmin: isAdmin,
  isModerator: isModerator,
  isModeratorOrAdmin: isModeratorOrAdmin
};
module.exports = authJwt;

middleware/index.js

const authJwt = require("./authJwt");
const verifySignUp = require("./verifySignUp");
module.exports = {
  authJwt,
  verifySignUp
};

Create Controllers

Controller for Authentication

There are 2 main functions for Authentication:

- signup: create new User in database (role is user if not specifying role)

- signin:

• find username of the request in database, if it exists
• compare password with password in database using bcrypt, if it is correct
• generate a token using jsonwebtoken
• return user information & access Token

controllers/auth.controller.js

const db = require("../models");
const config = require("../config/auth.config");
const User = db.user;
const Role = db.role;
const Op = db.Sequelize.Op;
var jwt = require("jsonwebtoken");
var bcrypt = require("bcryptjs");
exports.signup = (req, res) => {
  // Save User to Database
  User.create({
    username: req.body.username,
    email: req.body.email,
    password: bcrypt.hashSync(req.body.password, 8)
  })
    .then(user => {
      if (req.body.roles) {
        Role.findAll({
          where: {
            name: {
              [Op.or]: req.body.roles
            }
          }
        }).then(roles => {
          user.setRoles(roles).then(() => {
            res.send({ message: "User was registered successfully!" });
          });
        });
      } else {
        // user role = 1
        user.setRoles([1]).then(() => {
          res.send({ message: "User was registered successfully!" });
        });
      }
    })
    .catch(err => {
      res.status(500).send({ message: err.message });
    });
};
exports.signin = (req, res) => {
  User.findOne({
    where: {
      username: req.body.username
    }
  })
    .then(user => {
      if (!user) {
        return res.status(404).send({ message: "User Not found." });
      }
      var passwordIsValid = bcrypt.compareSync(
        req.body.password,
        user.password
      );
      if (!passwordIsValid) {
        return res.status(401).send({
          accessToken: null,
          message: "Invalid Password!"
        });
      }
      var token = jwt.sign({ id: user.id }, config.secret, {
        expiresIn: 86400 // 24 hours
      });
      var authorities = [];
      user.getRoles().then(roles => {
        for (let i = 0; i < roles.length; i++) {
          authorities.push("ROLE_" + roles[i].name.toUpperCase());
        }
        res.status(200).send({
          id: user.id,
          username: user.username,
          email: user.email,
          roles: authorities,
          accessToken: token
        });
      });
    })
    .catch(err => {
      res.status(500).send({ message: err.message });
    });
};

Controller for testing Authorization

There are 4 functions:
– /api/test/all for public access
– /api/test/user for loggedin users (role: user/moderator/admin)
– /api/test/mod for users having moderator role
– /api/test/admin for users having admin role

controllers/user.controller.js

exports.allAccess = (req, res) => {
  res.status(200).send("Public Content.");
};
exports.userBoard = (req, res) => {
  res.status(200).send("User Content.");
};
exports.adminBoard = (req, res) => {
  res.status(200).send("Admin Content.");
};
exports.moderatorBoard = (req, res) => {
  res.status(200).send("Moderator Content.");
};

Now, do you have any question? Would you like to know how we can combine middlewares with controller functions?
Let's do it in the next section.

Define Routes

When a client sends request for an endpoint using HTTP request (GET, POST, PUT, DELETE), we need to determine how the server will response by setting up the routes.

We can separate our routes into 2 part: for Authentication and for Authorization (accessing protected resources).

Authentication:

• POST /api/auth/signup
• POST /api/auth/signin

routes/auth.routes.js

const { verifySignUp } = require("../middleware");
const controller = require("../controllers/auth.controller");
module.exports = function(app) {
  app.use(function(req, res, next) {
    res.header(
      "Access-Control-Allow-Headers",
      "x-access-token, Origin, Content-Type, Accept"
    );
    next();
  });
  app.post(
    "/api/auth/signup",
    [
      verifySignUp.checkDuplicateUsernameOrEmail,
      verifySignUp.checkRolesExisted
    ],
    controller.signup
  );
  app.post("/api/auth/signin", controller.signin);
};

Authorization:

• GET /api/test/all
• GET /api/test/user for loggedin users (user/moderator/admin)
• GET /api/test/mod for moderator
• GET /api/test/admin for admin

routes/user.routes.js

const { authJwt } = require("../middleware");
const controller = require("../controllers/user.controller");
module.exports = function(app) {
  app.use(function(req, res, next) {
    res.header(
      "Access-Control-Allow-Headers",
      "x-access-token, Origin, Content-Type, Accept"
    );
    next();
  });
  app.get("/api/test/all", controller.allAccess);
  app.get(
    "/api/test/user",
    [authJwt.verifyToken],
    controller.userBoard
  );
  app.get(
    "/api/test/mod",
    [authJwt.verifyToken, authJwt.isModerator],
    controller.moderatorBoard
  );
  app.get(
    "/api/test/admin",
    [authJwt.verifyToken, authJwt.isAdmin],
    controller.adminBoard
  );
};

Don't forget to add these routes in server.js:

...
// routes
require('./app/routes/auth.routes')(app);
require('./app/routes/user.routes')(app);
// set port, listen for requests
...

Run & Test with Results

Run Node.js application with command: node server.js

Tables that we define in models package will be automatically generated in MySQL Database.
If you check the database, you can see things like this:

mysql> describe users;
+-----------+--------------+------+-----+---------+----------------+
| Field     | Type         | Null | Key | Default | Extra          |
+-----------+--------------+------+-----+---------+----------------+
| id        | int(11)      | NO   | PRI | NULL    | auto_increment |
| username  | varchar(255) | YES  |     | NULL    |                |
| email     | varchar(255) | YES  |     | NULL    |                |
| password  | varchar(255) | YES  |     | NULL    |                |
| createdAt | datetime     | NO   |     | NULL    |                |
| updatedAt | datetime     | NO   |     | NULL    |                |
+-----------+--------------+------+-----+---------+----------------+

mysql> describe roles;
+-----------+--------------+------+-----+---------+-------+
| Field     | Type         | Null | Key | Default | Extra |
+-----------+--------------+------+-----+---------+-------+
| id        | int(11)      | NO   | PRI | NULL    |       |
| name      | varchar(255) | YES  |     | NULL    |       |
| createdAt | datetime     | NO   |     | NULL    |       |
| updatedAt | datetime     | NO   |     | NULL    |       |
+-----------+--------------+------+-----+---------+-------+

mysql> describe user_roles;
+-----------+----------+------+-----+---------+-------+
| Field     | Type     | Null | Key | Default | Extra |
+-----------+----------+------+-----+---------+-------+
| createdAt | datetime | NO   |     | NULL    |       |
| updatedAt | datetime | NO   |     | NULL    |       |
| roleId    | int(11)  | NO   | PRI | NULL    |       |
| userId    | int(11)  | NO   | PRI | NULL    |       |
+-----------+----------+------+-----+---------+-------+

If you don't use initial() function in Sequelize sync() method. You need to run following SQL script:

mysql> INSERT INTO roles VALUES (1, 'user', now(), now());
mysql> INSERT INTO roles VALUES (2, 'moderator', now(), now());
mysql> INSERT INTO roles VALUES (3, 'admin', now(), now());

3 records will be created in roles table:

mysql> select * from roles;
+----+-----------+---------------------+---------------------+
| id | name      | createdAt           | updatedAt           |
+----+-----------+---------------------+---------------------+
|  1 | user      | 2020-01-13 09:05:39 | 2020-01-13 09:05:39 |
|  2 | moderator | 2020-01-13 09:05:39 | 2020-01-13 09:05:39 |
|  3 | admin     | 2020-01-13 09:05:39 | 2020-01-13 09:05:39 |
+----+-----------+---------------------+---------------------+

Register some users with /signup API:

• admin with admin role
• mod with moderator and user roles
• zkoder with user role

Our tables after signup could look like this.

mysql> select * from users;
+----+----------+--------------------+--------------------------------------------------------------+---------------------+---------------------+
| id | username | email              | password                                                     | createdAt           | updatedAt           |
+----+----------+--------------------+--------------------------------------------------------------+---------------------+---------------------+
|  1 | admin    | [email protected] | $2a$08$w3cYCF.N0UQZO19z8CQSZ.whzxFS5vMoi9k51g3TQx9r5tkwrIXO2 | 2020-01-13 09:21:51 | 2020-01-13 09:21:51 |
|  2 | mod      | [email protected]   | $2a$08$tTj1l28esAxPSSvl3YqKl./nz35vQF7Y76jGtzcYUhHtGy6d.1/ze | 2020-01-13 09:22:01 | 2020-01-13 09:22:01 |
|  3 | zkoder   | [email protected]  | $2a$08$U2F07dLyYZjzTxQbFMCAcOd1k8V1o9f6E4TGVJHpy0V6/DC7iS0CS | 2020-01-13 09:23:25 | 2020-01-13 09:23:25 |
+----+----------+--------------------+--------------------------------------------------------------+---------------------+---------------------+

mysql> select * from user_roles;
+---------------------+---------------------+--------+--------+
| createdAt           | updatedAt           | roleId | userId |
+---------------------+---------------------+--------+--------+
| 2020-01-13 09:22:01 | 2020-01-13 09:22:01 |      1 |      2 |
| 2020-01-13 09:23:25 | 2020-01-13 09:23:25 |      1 |      3 |
| 2020-01-13 09:22:01 | 2020-01-13 09:22:01 |      2 |      2 |
| 2020-01-13 09:21:51 | 2020-01-13 09:21:51 |      3 |      1 |
+---------------------+---------------------+--------+--------+

Access public resource: GET /api/test/all

Access protected resource: GET /api/test/user

Login an account (with wrong password): POST /api/auth/signin

Login an account: POST /api/auth/signin

Access protected resources: GET /api/test/user

Conclusion

Congratulation!

Today we've learned so many interesting things about Node.js Token Based Authentication with JWT - JSONWebToken in just a Node.js Express Rest Api example.

Despite we wrote a lot of code, I hope you will understand the overall architecture of the application, and apply it in your project at ease.