Sending and Receiving Cookies from Express.js

const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const productDao = require('./productDao.js');

// We will define this later
const sessionHandler = require('./sessionHandler');
const apiRouter = require('./apiRouter');
const app = express()

// Our API will be listening on port 4000
app.set('port', process.env.PORT || 4000)

// We support json requests
app.use(bodyParser.json())

// Allow cors everywhere
app.use(cors())

// This will manage our sessions
app.use(sessionHandler)

// Our app had one route to get the products in our database
app.use('/api', apiRouter)

// Launching our server on our app's port
const server = app.listen(app.get('port'), () => {
 console.log(`Shopping App is running on port ${app.get('port')}`)
})

export default server

const router = require('express')

// Our app had one route to get the products in our database
app.get('/product/all', (req, res) => {

// This array simulates our database
const allProducts = [
  {name: 'blue cheese', type:'cheese'},
  {name: 'brocolli', type: 'vegetable'},
  {name: 'cookie', type: 'snack'}
 ];
 res.status(200).send(allOurProducts)
})

// add item to the cart
app.post('/cart', (req,res)=> {
 // We'll write this code later
})

// get all items in the shopping cart
app.post('/cart', (req,res)=> {
 // We'll write this code later
})

// Allows our user to checkout
app.post('/checkout', (req, res) => {
 // We'll write this code later
})

// sentTokenCookie creates a cookie which expires after one day
const sendUserIdCookie = (userId, res) => {
 // Our token expires after one day
 const oneDayToSeconds = 24 * 60 * 60;
 res.cookie('userId', userId,  
 { maxAge: oneDayToSeconds,
 // You can't access these tokens in the client's javascript
   httpOnly: true,
   // Forces to use https in production
   secure: process.env.NODE_ENV === 'production'? true: false
  });
};

// returns an object with the cookies' name as keys
const getAppCookies = (req) => {
 // We extract the raw cookies from the request headers
 const rawCookies = req.headers.cookie.split('; ');
 // rawCookies = ['myapp=secretcookie, 'analytics_cookie=beacon;']

 const parsedCookies = {};
 rawCookies.forEach(rawCookie=>{
 const parsedCookie = rawCookie.split('=');
 // parsedCookie = ['myapp', 'secretcookie'], ['analytics_cookie', 'beacon']
  parsedCookies[parsedCookie[0]] = parsedCookie[1];
 });
 return parsedCookies;
};

// Returns the value of the userId cookie
const getUserId = (req, res) =>  getAppCookies(req, res)['userId'];

// Our application store is stateful and uses a variable
const sessions = {};

const sessionHandler = (req, res, next)=> {
 // extracting the user id from the session
 let userId = getUserId(req, res);

 // If we don't have a userId or the session manager doesn't recognize the userId
 // then we create a new one one
  if(!userId || !sessions[userId]) {
   // this should create a time based unique identifier
    userId = uuidv1();
    sessions[userId] = {
    cart: {}
  };
  // Clearing the cookies in case the session userid is not valid
  res.clearCookie('userId');
  // Returning the newly assigned cookie value
  sendUserIdCookie(userId, res);
 }

 req.session = sessions[userId];
 // Now in our route handlers you'll have session information in req.session
 next();
};

router.get('/cart', (req, res) => {
 // Returns the value of the cart
 const cart = req.session.cart;
 res.status(200).send(cart);
});

router.post('/cart', (req, res) => {
 const cart = req.session.cart;
 const productName = req.body.productName;

 // Fancy stupid trick to do create a key with the value 1
 // or if the key exists increment the value by 1
 cart[productName] = -~ cart[productName];
 return res.status(200).send('success');
});

router.post('/checkout', (req, res)=> {
 // We want to clear the cookies
 res.clearCookie('userId');
});

module.exports = router;