nodejs-jwt

Nodejs app with expressjs RESTAPI and JSON Web Token to check authentification sample.

Before the start

Clone this repository and run:

npm install
npm start

Use case with nodejs server and curl client

Send a login request with curl and add two parameters:

• admin = [email protected]
• password = admin

curl -d "[email protected]&password=admin" -X POST http://localhost:8080/login

A valid token is returned:

{
  "email":"[email protected]","token":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6IjEiLCJpYXQiOjE1MjI0MjEyODAsImV4cCI6MTUyMjQyNDg4MH0.Lt4zggS4xv_nFru_Vvob_S1KGIAHth_ifxr6g4VN5R0"
}

Use that token to send next request to the API at http://localhost:8080/api/helloworld

curl -H "Authorization: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6IjEiLCJpYXQiOjE1MjI0MjEyODAsImV4cCI6MTUyMjQyNDg4MH0.Lt4zggS4xv_nFru_Vvob_S1KGIAHth_ifxr6g4VN5R0" -X GET "http://localhost:8080/api/helloworld"

The server check if a valid token is present in Authorization header and returns a HelloWorld:

{"message":"Helloworld"}

Try with an invalid token:

curl -H "Authorization: wrong-token" -X GET "http://localhost:8080/api/helloworld"

The server returns a token error:

{"error":"Failed to authenticate token!"}

Project description

Install the jsonwebtoken:

npm install jsonwebtoken --save

Create a middleware auth.js to check JWT. Change the secret by what do you want.

// ./routes/api/middlewares/auth.js

const jwt = require('jsonwebtoken');
const fs = require('fs');

module.exports = function (req, res, next) {

  // Check if authorization header is set with a JWT valid
  if (req.hasOwnProperty('headers') && req.headers.hasOwnProperty('authorization')) {
    try {
      // Decode JWT and keep user id (you can add more value)
      req.user = jwt.verify(req.headers['authorization'], 'secret'); // secret key here
    } catch (err) {
      // Invalid token
      return res.status(401).json({
        error: 'Failed to authenticate token!'
      });
    }
  } else {
    // No token present in header
    return res.status(401).json({
      error: 'No token!'
    });
  }
  next();
  return;
};

Add this middleware to the /api/ route in app.js.

// ./app.js

[...]

// Add middleware. Because we defined the first parameter ( '/api' ), it will run
// only for urls that starts with '/api/*'
app.use('/api', require('./routes/api/middlewares/auth.js'));

[...]

Add a login router to generate the token.

// ./routes/login.js

const express = require('express');
const asyncHandler = require('express-async-handler');
const jwt = require('jsonwebtoken');
const fs = require('fs');

var router = express.Router();
router.route('/')

  .post(asyncHandler(async (req, res, next) => {
    const email = req.body.email;
    const password = req.body.password;

    // check login information
    if (email === '[email protected]' && password === 'admin') {
      // build json response with JWT valid token
      let user = {
        email: email,
        token: jwt.sign({
          id: '1',
        }, 'secret', { expiresIn: 60 * 60 }) // use secret key
      }
      res.status(200).json(user);
    }
    else {
      res.status(401).json({
        error: 'wrong username or password!'
      });
    }
  }))

module.exports = router;