Socket connection inside route

Socket connection inside route

I'm trying to clean up my express node app by maintaining all of the
socket.io functionality inside express routes, or router pages (relying on
a question answered here: Nodejs include socket.io in router page). For
some unknown reason, no socket connection ever opens (no "success" is ever
logged).
//app.js
server = http.createServer(app).listen(3000);
app.get('/', function(req,res){
routes.index(req,res,app,server);
});
With my routes.index looking like this:
//routes.index
var socketio = require('socket.io');
exports.index = function(req,res,app,server){
var io = socketio.listen(server);
server.listen(3000);
console.log("routed correctly?"); //yes, it is routed correctly.
io.sockets.on('connection', function (socket) {
console.log("success");
});
res.render('index');
};
Any ideas? Much appreciated.