To create a token with expiration

token.js

// Express web app
const express = require('express');
const app = express()
const md5 = require('md5');

// Redis client
const redis = require("redis");
const client = redis.createClient({ host: '192.168.178.23' });

// Token generator
const TokenGenerator = require('uuid-token-generator');
const tokgen = new TokenGenerator();

// Express login & token generation
app.get("/login", function(req, res){
  const {username, password} = req.query;
  if(username && password) {
    client.get('users/' + username + ':mmd5', function(err, data) { // Check password.
      if(data == md5(password)) {
        let token = tokgen.generate();
        // Send the token back for use by the frontend (typically store it in the cookies)
        res.send(token);
        // Save the token in the Redis DB
        client.set('users/' + username + ':token-'+token, { 'whatever': 'data' }, 'EX', 10*86400); 
      } else {
        res.status(403).send('Invalid password or username.');
      };
      res.end();
    });
  } else {
    res.status(403).send('No password or username given.');
  }
});

// Token verification on the cookies:
// success, data = check_token(username, token);
function check_token(username, token) {
  if(username && token) {
    client.get('users/' + username + ':token-'+token, function(err, data) {
      // data is null if the key is not found.
      return data!=null, data;
    });
  }
  return false, null;
}

app.listen(3000,  () => console.log(`Listening on port 3000.`));