Passport + Socket.io get logged user id - node.js

Question

I'm making a Node.js app and I need to create a new document in mongoDB inside socket.io.
I have to insert the logged in user in the new document.
How can I access the session variable inside socketio ?
// INCLUDE MODULES =======================================================
var SocketIOFileUpload = require("socketio-file-upload");
var express = require('express');
var app = express();
var server = require('http').createServer(app);
var socketio = require('socket.io');
var Twig = require('twig');
var twig = Twig.twig;
var path = require('path');
var mongoose = require('mongoose');
var passport = require('passport');
var Cookies = require( "cookies" );
var flash = require('connect-flash');
var configDB = require('./config/database.js');
var connect = require('connect');
var ImageFile = require('./app/models/image');
// Assets ================================================================
app.use(express.static(path.join(__dirname, 'public')));
app.use(connect.favicon(path.join(__dirname, 'public/images/favicon.ico')));
// Start mongoose
mongoose.connect(configDB.url);
// USER MANAGEMENT =======================================================
require('./config/passport')(passport); // pass passport for configuration
app.use(connect.logger('dev')); // log every request to the console
app.use(connect.cookieParser()); // read cookies (needed for auth)
app.use(connect.json()); // to support JSON-encoded bodies
app.use(SocketIOFileUpload.router); //socket io file upload
app.use(connect.urlencoded()); // to support URL-encoded bodies
app.set('view engine', 'twig'); // set up twig for templating
app.use(connect.session({ secret: 'ilovescotchscotchyscotchscotch' })); // session secret
app.use(passport.initialize());
app.use(passport.session()); // persistent login sessions
app.use(flash());
// Some more code ...
//SOCKET IO =======================================================
//Quand on client se connecte, on le note dans la console
var io = socketio.listen(server);
io.sockets.on("connection", function(socket){
// Make an instance of SocketIOFileUpload and listen on this socket:
var session = socket.handshake.session;
var uploader = new SocketIOFileUpload();
uploader.dir = "/LeafStore/public/uploads";
uploader.listen(socket);
console.log(socket.handshake.user);
// Do something when a file is saved:
uploader.on("saved", function(event, socket){
console.log(event.file);
});
// Do something when a file is saved:
uploader.on("complete", function(event){
console.log("saving file" + name);
console.log(event);
var name = event.file.name;
var imageData = {
name: name
, type: "image"
, userId: ""
, creationDate: new Date()
};
var newImage = new ImageFile(imageData);
newImage.save( function(error, data){
if(error){
throw error;
}
else{
}
});
// save the user
newImage.save(function(err) {
if (err)
throw err;
});;
});
// Error handler:
uploader.on("error", function(event){
console.log("Error from uploader", event);
});
});
// LISTEN SERVER =======================================================
server.listen(80);

Answer 1

I found a temporary solution :
I emit the user Id in my views :
socket.emit('userId', $("#userId").val());
Then I set the socket.userId var :
socket.on('userId', function(userId){
socket.userId = userId;
});
But it's probably unsafe