server.js

// server.js
// where your node app starts

// init project
const express = require('express'),
      sqlite3 = require('sqlite3').verbose(),
      bodyParser = require('body-parser'),
      passport = require('passport'),
      Local = require('passport-local').Strategy,
      session = require('express-session'),
      cookieParser = require('cookie-parser'),
      low = require('lowdb'),
      FileSync = require('lowdb/adapters/FileSync'),
      helmet = require('helmet'),
      app = express();

const userAdapter = new FileSync('users.json');
const userdb = low(userAdapter);
let credential = '';

passport.serializeUser( ( user, done ) => {
    done( null, user.username ) 
})

passport.deserializeUser( ( username, done ) => {
  const user = userdb.find( u => u.username === username ).value()
  credential = username
  
  if( user !== undefined ) {
    done( null, user )
  }else{
    done( null, false, { message:'user not found; session not restored' })
  }
})

app.use(helmet())

// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: false }))

// parse application/json
app.use(bodyParser.json())

console.log( '#'+Math.floor(Math.random()*167772153298472234).toString(16) )

// http://expressjs.com/en/starter/static-files.html
app.use(cookieParser());
app.use(require('express-session')({
    secret: process.env.SECRET,
    resave: false,
    saveUninitialized: false
}));
app.use(passport.initialize());
app.use(passport.session());

userdb.defaults({ users: [] })
  .write();

// //--------------------------------------------------------------------------------------//

// Create dB

// //--------------------------------------------------------------------------------------//
 
// open database in memory
let db = new sqlite3.Database(':memory:', (err) => {
  if (err) {
    return console.error(err.message);
  }
  console.log('Connected to the in-memory SQlite database.');
  
});

db.serialize(function () {
  db.run('CREATE TABLE deck_list (user TEXT, quantity INTEGER, card_name TEXT, set_name TEXT)');
  var stmt = db.prepare("INSERT INTO deck_list VALUES ('Andrew', 2, 'Ugin, the Spirit Dragon', 'Fate Reforged')");
  stmt.run()
  var stmt = db.prepare("INSERT INTO deck_list VALUES ('Hand', 1, 'Mind Slaver', 'Mirrodan')");
  stmt.run()
  stmt.finalize()
  
})
 
// // close the database connection
// db.close((err) => {
//   if (err) {
//     return console.error(err.message);
//   }
//   console.log('Close the database connection.');
// });

// we've started you off with Express, 
// but feel free to use whatever libs or frameworks you'd like through `package.json`.

// http://expressjs.com/en/starter/static-files.html
app.use(express.static('public'));

// http://expressjs.com/en/starter/basic-routing.html
app.get('/', function(request, response) {
  response.sendFile(__dirname + '/views/index.html');
});
 
app.get('/index.html', function(request, response) {
  response.sendFile(__dirname + '/views/index.html');
});


// all authentication requests in passwords assume that your client
// is submitting a field named "username" and field named "password".
// these are both passed as arugments to the authentication strategy.
const myLocalStrategy = function( username, password, done ) {
    // find the first item in our users array where the username
    // matches what was sent by the client. nicer to read/write than a for loop!
    const user = userdb.get( 'users' )
                       .find({ username: username})
                       .value()
    
    // if user is undefined, then there was no match for the submitted username
    if( user === undefined ) {
      /* arguments to done():
       - an error object (usually returned from database requests )
       - authentication status
       - a message / other data to send to client
      */
     console.log('user not found')
      return done( null, false, { message:'user not found' })
    }else if( user.password === password ) {
      // we found the user and the password matches!
      // go ahead and send the userdata... this will appear as request.user
      // in all express middleware functions.
      console.log('user found')
      return done( null, { username, password })
    }else{
      // we found the user but the password didn't match...
      console.log('password not found')
      return done( null, false, { message: 'incorrect password' })
    }
}
passport.use(new Local(myLocalStrategy))

app.get('/redirect-login', (request, response) => response.sendFile(__dirname + '/views/login.html'));
app.get('/redirect-signup', (request, response) => response.sendFile(__dirname + '/views/signup.html'));
app.post('/signout', function(request, response) {
    request.session.destroy()
    credential = ''
    response.redirect('/redirect-login')
    response.end()
});
app.post('/login', passport.authenticate('local', {
    successRedirect: '/',
    failureRedirect: '/redirect-login'
}),
    function (request, response) {
        response.json({ status: true })
    }
  )
app.post('/signup', function(request, responce) {
  const body = request.body
  let userAttempt = body.username
  let passAttempt = body.password

  // Add a post
  userdb.get('users')
    .push({ username: userAttempt, password: passAttempt })
    .write()

  responce.writeHead(200, "OK", { 'Content-Type': 'text/plain' })
  responce.end()
})


// //--------------------------------------------------------------------------------------

// Read, write, modify database using the following expressions

// //--------------------------------------------------------------------------------------

app.get('/read', function(request, response) {
  let rows = []
  db.each(
    "SELECT quantity, card_name, set_name FROM deck_list WHERE user = '" + credential + "'",
    function(err, row) { rows.push(row) },
    function() { response.end( JSON.stringify(rows) ) }
  )
});

app.post('/update', function(request, response) {
  // response.sendFile(__dirname + '/views/index.html');
  console.log(request.body);
  let quantity = request.body['quantity'],
      card_name = request.body['card_name'],
      set_name = request.body['set_name'];
  db.run("UPDATE deck_list SET quantity = " + quantity + " WHERE card_name = '" + card_name + "' AND set_name = '" + set_name + "' AND user = '" + credential + "'");
});

app.post('/add', function(request, response) {
  // response.sendFile(__dirname + '/views/index.html');
  console.log(request.body)
  let quantity = request.body['quantity'],
      card_name = request.body['card_name'],
      set_name = request.body['set_name'];
  console.log(quantity);
  console.log(card_name);
  console.log(set_name);
  db.run("INSERT INTO deck_list VALUES ('" + credential + "',"+ quantity + ",'" + card_name + "','" + set_name + "')");
});

app.put('/delete', function(request, response) {
  let card_name = request.body['card_name'],
      set_name = request.body['set_name'];
  db.run("DELETE FROM deck_list WHERE card_name = '"+ card_name + "' AND set_name = '" + set_name + "' AND user = '" + credential + "'");
});

// listen for requests :)
const listener = app.listen(process.env.PORT, function() {
  console.log('Your app is listening on port ' + listener.address().port);
});