Node.js Express using Session with Redis Cluster

Dependencies

• express
• express-session
• connect-redis
• ioredis

  $ npm install express express-session connect-redis ioredis

Redis – Single Node

1. install & run redis
2. run in cmd

   $ redis-cli

3. run this in redis-cli

   redis> FLUSHALL
   redis> keys *

4. then there are no keys in redis store.
5. and make js file for running express. refer below code

   var express = require('express');
   var app = express();
   
   var session = require('express-session');
   var RedisStore = require('connect-redis')(session);
   
   var Redis = require('ioredis');
   var redisClient = new Redis({port: 6379, host: 'localhost'});
   
   app.use(session({
       secret: 'redis-session-test',
       store: new RedisStore({client: redisClient}),
       resave: false,
       saveUninitialized: true
   }));
   
   app.get('/session', function (req, res) {
       var session = req.session;
       console.log(session.user);
       if (session.user) {
           res.send('session already saved. user = ' + session.user);
       } else {
           session.user = 'test';
           res.send('session saved');
       }
   });
   
   app.listen(5000, function () {
       console.log('Web Console @ 127.0.0.1: 5000');
   });

6. connect to ‘localhost:5000/session’. then you can show message ‘session saved’
7. refresh web browser, then message change to ‘session already saved. user = test’
8. you can show key that is created by express session

   redis> keys *

Redis – Multi Node

1. change code, redisClient in upper code. make sure that add all node ip in your cluster to option.

   var redisClient = new Redis.Cluster([
       {port: 6379, host: 'your-cluster-ip-1'},
       {port: 6379, host: 'your-cluster-ip-2'},
       {port: 6379, host: 'your-cluster-ip-3'},
       {port: 6379, host: 'your-cluster-ip-4'}
   ]);
   

2. find keys in your cluster