[Easy] Complete user Login and Registration using NodeJS, ExpressJs, MySQL and JWT.

const express = require('express');
const app = express();
const port = process.env.PORT || 5000;

app.listen(port, () => {
    console.log('Server Started');
});

const express = require('express');
const mysql = require('mysql');
const exphbs = require('express-handlebars');
const bodyParser = require('body-parser');
const cookieParser = require('cookie-parser');
require('dotenv').config();

const app = express();
const port = process.env.PORT || 5000;

app.use(bodyParser.urlencoded({
    extended: false
}))

// Converting JSON to JavaScript Objects
app.use(bodyParser.json());

// Accessing Cookies from user's Browser
app.use(cookieParser())

// Telling our backend that the static files of our website are going to be in which folder!!
app.use(express.static('public'));

//Template Engines 
app.engine("hbs", exphbs({ extname: '.hbs' }))
app.set('view engine', 'hbs');

// DataBase Credentials
const pool = mysql.createPool({
    connectionLimit: 100,
    host           : 'localhost',
    user           : 'root',
    password       : '',
    database       : 'users',
})

// Connecting to DB
pool.getConnection((err, connection)=>{
    if(err){
        throw err;
    }
    else{
        console.log('Connection Successful and Connected');
    }
});

// All Routers Middleware Setup => 
const homeRoutes = require('./server/routes/homeRoutes');
app.use('/', homeRoutes);

const authRoutes = require('./server/routes/authRoutes');
app.use('/auth', authRoutes);

app.listen(port, () => {
    console.log('Server Started');
});

//type this following code in authRoute.js

const router = require('express').Router();
const { tokenValidation } = require('../../auth/userToken');
const controllers = require('../controllers/authController');

// Routes
// Login
router.get('/login', controllers.ViewLoginPage)
router.post('/login', controllers.Loginuser)

// Register
router.get('/register', controllers.ViewRegisterPage)
router.post('/register', controllers.RegisterNewPage)

module.exports = router;

const router = require('express').Router();
const controllers = require('../controllers/homeController');
const { tokenValidation } = require('../../auth/userToken');

// Routes
router.get('/', controllers.HomePage);
router.get('/user-profile', tokenValidation, controllers.userProfilePage);

//NOTE: dont get confuse with why am i passing to middlewares in route user-profile, once we learn the JWT then you will get this.

module.exports = router;

//type the following code in authControllers.js


const mysql = require('mysql');
const { hashSync, genSaltSync, compareSync } = require('bcrypt');
const { sign } = require('jsonwebtoken');
require('dotenv').config();

const pool = mysql.createPool({
    connectionLimit: 100,
    host: "localhost",
    user: "root",
    password: "",
    database: "users",
})


exports.ViewLoginPage = (req, res) => {
    res.render('login', { title: 'Login' })
}
exports.ViewRegisterPage = (req, res) => {
    res.render('register', { title: 'Register' })
}


//Registration of user
exports.RegisterNewPage = (req, res) => {
    const {name, email, password, bio} = req.body;

    //Generating salt for Hashing
    const salt = genSaltSync(10);

    //Hashing the password
    const hashPassword = hashSync(password, salt);


    // Connecting to DB
    pool.getConnection((err, connection) => {
        if (err) {
            throw err;
        }
        else {
            connection.query('select email from users where email = ?', [email], (err, data) => {
                console.log(data)
                if (data.length != 0) {
                    res.render('register', {message: 'Already Registered'})

                }
                else{
                    connection.query('INSERT INTO users SET name = ?, email = ?, bio = ?, password = ?', [name, email, bio, hashPassword], (err, newRegisteredUser) => {
                        if(err){
                            res.render('register', {message: 'Something went wrong, Please try again'})
                        }
                        res.redirect('/auth/login/')
                    })
                }
            })


        }
    });
}

//Login the user
exports.Loginuser = (req,res) => {
    const {email, password} = req.body;
    pool.getConnection((err, connection) => {
        if (err) {
            throw err;
        }
        else {
            connection.query('SELECT * FROM users WHERE email = ?', [email], (err,data) => {
                if(err){
                    res.render('login', {message: 'Email or Password is Incorrect'});
                }
                if(data.length == 0){
                    res.render('login', {message: `Email Doesn't exist, Try to register`})
                }
                else{
                    const checkPassword = compareSync(password, data[0].password);
                    if(checkPassword){

                    //Creating the token for logged in user
                        const userToken = sign({result: data[0].email}, process.env.SECRET_KEY, {
                            expiresIn: '600s'
                        })

                        //Sending the token to user's cookie
                        res.cookie('userToken', userToken, {
                            expires: new Date(Date.now() + 600000),
                            httpOnly: true
                        })
                        console.log(userToken)
                        res.redirect('/')
                    };
                    else{
                        res.render('login', {message: 'Email or Password is Incorrect'})
                    };
                };
            });
        };
    });
};

type the following code in homeControllers.js

const cookieParser = require('cookie-parser');
const { verify } = require('jsonwebtoken');
const mysql = require('mysql');
require('dotenv').config();

const pool = mysql.createPool({
    connectionLimit: 100,
    host: "localhost",
    user: "root",
    password: "",
    database: "users",
})

exports.HomePage = (req, res) => {
    const userToken = req.cookies.userToken;
    if (userToken) {
        verify(userToken, process.env.SECRET_KEY, (err, decoded) => {
            if (err) {
                res.render('home',{ notUser: true })
            }
            else {
                let userEmail = decoded.result;
                pool.getConnection((err, connection) => {
                    if (err) {
                        throw err;
                    }
                    else {
                        connection.query('SELECT * FROM users WHERE email = ?', [userEmail], (err,data) => {
                            res.render('home', {data})
                        })  
                    }
                });

            }
        })
    }
    else {
        res.render('home',{notUser: true})
    }
}


exports.userProfilePage = (req, res) => {
    const userToken = req.cookies.userToken;
    if (userToken) {
        verify(userToken, process.env.SECRET_KEY, (err, decoded) => {
            if (err) {
                res.redirect('/auth/login/')
            }
            else {
                let userEmail = decoded.result;
                pool.getConnection((err, connection) => {
                    if (err) {
                        throw err;
                    }
                    else {
                        connection.query('SELECT * FROM users WHERE email = ?', [userEmail], (err,data) => {
                            res.render('userProfile', {data})
                        })  
                    }
                });

            }
        })
    }
    else {
        res.redirect('/auth/login/')
    }
}

type this code in userToken.js

const { verify } = require('jsonwebtoken');
require('dotenv').config()

exports.tokenValidation = (req,res,next) => {

    //geeting the stored cookie from user
    const userToken = req.cookies.userToken;
    if(userToken){

        //verifiying the stored cookie from user
        verify(userToken, process.env.SECRET_KEY, (err, decoded) => {
            if(err){
                res.redirect('/auth/login/')
            }
            else{
                // next will help to jump on next controller
                next()
            }
        })
    }
    else{
        res.redirect('/auth/login/')
    }
}