Socket.io cleans the req.session session

I have an app that uses express, express-session, socket.io and socket.io.streams. The client connects to the server using:

  

socket.connect ('/ namespace')

But when the connection is achieved, my req.session object remains empty. Does anyone know how to prevent this from happening?

This is the configuration of express sessions:

 // app.js 
 var session = require('express-session');
 var MySQLStore = require('express-mysql-session')(session);
 var sessionStore = new MySQLStore({
                          "host": "localhost",
                          "port": 3306,
                          "user": "root",
                          "password": "somepass",
                          "database": "databse",
                          "checkExpirationInterval": 0,
                          "createDatabaseTable": true,
                          "schema": {
                            "tableName": "sessions_user"
                          }
                    });
app.use(session({
                  key: 'YUYUY6T76F78TF8YV9YV54S3A2A4D5F8',
                  secret: '2MDT6T6T6T6T6T65DA4ZCM',
                  store: sessionStore,
                  resave: true,
                  saveUninitialized: true,
                  maxAge: 20000,
                  cookie: {
                   secure: false,
                   maxAge: 600000
                  }
              }));

The way I start the server is very simple

// bin/www
var app = require('../app');
var server = http.createServer(app);
var io = require('socket.io').listen(server);