EDIT 2015/09/16: I realised adding event listeners in middleware is not a smart thing to do (hint: middleware gets called on every request) and have therefore updated this guide. Also, I have added session sharing between Express and Socket.IO for accessing stuff like req.params.id from Socket.IO.

To integrate Socket.IO with KeystoneJS requires some work but it can be done, at least using the packages keystone 0.3.14 and socket.io 1.3.6 from npm.

The steps below assume you have followed the Getting Started guide and have a folder structure as stated in the guide. ./web.js is the entry point for the app, ./routes/views/index.js is the route controller for index and ./templates/views/index.jade is the jade template rendered for index.

Firstly, npm install --save socket.io to get Socket.IO and update your ./package.json.

Change the following in ./web.js

//replace this
keystone.start();

//with this
var socketio = require('socket.io');
keystone.start({
    onHttpServerCreated: function(){
        keystone.set('io', socketio.listen(keystone.httpServer));
    },
    onStart: function(){
        var io = keystone.get('io');
        var session = keystone.get('express session');

        // Share session between express and socketio
        io.use(function(socket, next){
            session(socket.handshake, {}, next);
        });

        // Socketio connection
        io.on('connect', function(socket){
            console.log('--- User connected');
            
            // Set session variables in route controller
            // which is going to load the client side socketio
            // in this case, ./routes/index.js
            console.log(socket.handshake.session);
            socket.emit('msg', socket.handshake.session.message);


            socket.on('disconnect', function(){
                console.log('--- User disconnected');
            });
        });
    }
});

Set the session variable in ./routes/views/index.js by adding into the module.exports function

req.session.message = 'Hello World';

Load /socket.io/socket.io.js on the client’s side by adding script tags to ./templates/views/index.jade

<script src="/socket.io/socket.io.js"></script>
<script>

    var socket = io();
    socket.on('msg', function(message){
        console.log(message);
    });

</script>

Now to check if Socket.IO is working and session sharing between Express and Socket.IO is enabled, start the app with node ./web.js and connect to the server from the client. You should see on the server console

--- User connected

and on the browser console

'Hello World'