index.js

'use strict'

/**
 * Module dependencies.
 */

const express = require('../../')
const hash = require('pbkdf2-password')()
const path = require('node:path')
const session = require('express-session')

const app = module.exports = express()

// config

app.set('view engine', 'ejs')
app.set('views', path.join(__dirname, 'views'))

// middleware

app.use(express.urlencoded())
app.use(session({
  resave: false, // don't save session if unmodified
  saveUninitialized: false, // don't create session until something stored
  secret: 'shhhh, very secret'
}))

// Session-persisted message middleware

app.use((req, res, next) => {
  const err = req.session.error
  const msg = req.session.success
  delete req.session.error
  delete req.session.success
  res.locals.message = ''
  if (err) res.locals.message = '<p class="msg error">' + err + '</p>'
  if (msg) res.locals.message = '<p class="msg success">' + msg + '</p>'
  next()
})

// dummy database

const users = {
  tj: { name: 'tj' }
}

// when you create a user, generate a salt
// and hash the password ('foobar' is the pass here)

hash({ password: 'foobar' }, (err, pass, salt, hash) => {
  if (err) throw err
  // store the salt & hash in the "db"
  users.tj.salt = salt
  users.tj.hash = hash
})

// Authenticate using our plain-object database of doom!

function authenticate (name, pass, fn) {
  if (!module.parent) console.log('authenticating %s:%s', name, pass)
  const user = users[name]
  // query the db for the given username
  if (!user) return fn(null, null)
  // apply the same algorithm to the POSTed password, applying
  // the hash against the pass / salt, if there is a match we
  // found the user
  hash({ password: pass, salt: user.salt }, (err, pass, salt, hash) => {
    if (err) return fn(err)
    if (hash === user.hash) return fn(null, user)
    fn(null, null)
  })
}

function restrict (req, res, next) {
  if (req.session.user) {
    next()
  } else {
    req.session.error = 'Access denied!'
    res.redirect('/login')
  }
}

app.get('/', (req, res) => {
  res.redirect('/login')
})

app.get('/restricted', restrict, (req, res) => {
  res.send('Wahoo! restricted area, click to <a href="/logout">logout</a>')
})

app.get('/logout', (req, res) => {
  // destroy the user's session to log them out
  // will be re-created next request
  req.session.destroy(() => {
    res.redirect('/')
  })
})

app.get('/login', (req, res) => {
  res.render('login')
})

app.post('/login', (req, res, next) => {
  if (!req.body) return res.sendStatus(400)
  authenticate(req.body.username, req.body.password, (err, user) => {
    if (err) return next(err)
    if (user) {
      // Regenerate session when signing in
      // to prevent fixation
      req.session.regenerate(() => {
        // Store the user's primary key
        // in the session store to be retrieved,
        // or in this case the entire user object
        req.session.user = user
        req.session.success = 'Authenticated as ' + user.name +
          ' click to <a href="/logout">logout</a>. ' +
          ' You may now access <a href="/restricted">/restricted</a>.'
        res.redirect(req.get('Referrer') || '/')
      })
    } else {
      req.session.error = 'Authentication failed, please check your ' +
        ' username and password.' +
        ' (use "tj" and "foobar")'
      res.redirect('/login')
    }
  })
})

/* istanbul ignore next */
if (!module.parent) {
  app.listen(3000)
  console.log('Express started on port 3000')
}