get session from socket.io

app.js

var express       = require('express');
var parse_cookie  = require('connect').utils.parseCookie;
var MemoryStore   = express.session.MemoryStore;
var session_store = new MemoryStore();
var app           = module.exports = express.createServer();

app.configure(function(){
  app.use(express.bodyParser());
  app.use(express.cookieParser());
  app.use(express.methodOverride());
  app.use(express.session({
    store  : session_store,
    secret : 'secret-key',
    key    : 'express.sid'
  }));
});

var io = require('socket.io').listen();
io.configure(function(){
  io.set('log level', 1);
  io.set('authorization', function(data, accept){
    if(data.headers.cookie){
      data.cookie     = parse_cookie(data.headers.cookie);
      data.session_id = data.cookie['express.sid'];
      session_store.get(data.session_id, function(error, session){
        data.session = error ? null : session;
        accept(null, true);
      });
    } else {
      data.session = null;
      accept(null, true)
    }
  });
});