application.js

var q= function(s){ return document.getElementById(s) }

function send(){
  var input = q('text');
  socket.send(input.value);
  input.value = '';
}

var socket = new io.Socket(null, {
  port: 8001,
  rememberTransport: false
});

socket.on('message', function(message){
  var el = document.createElement('p');
  el.innerHTML = message;
  q('chat').appendChild(el);
});

socket.connect();

index.jade

!!! 5
html(lang="en")
  head
    title chat
    meta(charset="utf-8")
    link(rel="stylesheet", href="/master.css")
    script(src="http://cdn.socket.io/stable/socket.io.js")
    script(src="/application.js")
  body
    h1 Sample chat client
    div#chat
    form#form(onsubmit="send();return false")
      input#text(type="text", autocomplete="off")

master.css

#chat p { 
  padding: 8px; 
  margin: 0; 
}
#chat p:nth-child(odd) { 
  background: #F6F6F6; 
}
form { 
  background: #444; 
  padding: 5px 10px; 
}
form input[type=text] { 
  width: 98%; 
  padding: 5px; 
  background: #fff; 
}

package.json

{
  "name": "redispubsub",
  "version": "0.0.2",
  "dependencies": {
    "connect": "1.3.0",
    "express": "2.2.1",
    "jade": "0.10.4",
    "socket.io": "0.6.17",
    "redis":"0.5.11"
  }
} 

server.js

var express = require("express")
var socketio = require("socket.io")
var redis = require("redis")

// redis clients
var store = redis.createClient()
var pub = redis.createClient()
var sub = redis.createClient()

var app = express.createServer(express.static(__dirname + '/public'))
app.set('view engine', 'jade')

app.get("/", function(req, rsp){
  rsp.render('index', { layout: false })
})

app.listen(8001)
  
var socket = socketio.listen(app)

sub.subscribe("chat")

socket.on("connection", function(client){
  client.send("welcome!")

  client.on("message", function(text){
    store.incr("messageNextId", function(e, id){
      store.hmset("messages:" + id, { uid: client.sessionId, text: text }, function(e, r){
        pub.publish("chat", "messages:" + id)
      })
    })
  })
  
  client.on("disconnect", function(){
    client.broadcast(client.sessionId + " disconnected")
  })

  sub.on("message", function(pattern, key){
    store.hgetall(key, function(e, obj){
      client.send(obj.uid + ": " + obj.text)
    })
  })
    
})