Making Express, Socket.IO, and Angular play nicely together

main.js

// File: client/scripts/controllers/main.js

// With this, you can use 'socket' very nicely (IMHO)
'use strict';

angular.module('theApp')
  .controller('MainCtrl', function ($scope, socket) {

    $scope.now = 'loading...';

    var ioTime = socket.connect('/io/time');
    ioTime.on('time', function(now) {
      $scope.now = now;
    });

    var ioPing = socket.connect('/io/ping');
    ioPing.on('pong', function(data) {
      console.log(data);
    });

  });

server.js

// File: server/server.js

// This is the Node file to fire up an Socket.IO enabled Express server
// Code your io stuff as normal
var express       = require('express'),
    session       = require('express-session'),
    bodyParser    = require('body-parser'),
    cookieParser  = require('cookie-parser'),
    http          = require('http'),
    socketio      = require('socket.io');

var app = express();
var server = http.createServer(app);
var io = socketio.listen(server);
var sessionStore = new session.MemoryStore();

app.use(express.static(__dirname+'/../client')); // serve the client
app.use(bodyParser());
app.use(cookieParser());
app.use(session({
  store: sessionStore,
  secret: ''+new Date().getTime()
}));

// this is the authentication middleware that links the 
// Express session with the socket.  You need to manage
// the session within the authentication stack of the
// Express app:
/*
  app.get('/signout', function(req, res) {
    ...
    req.session.destroy();
    ...
  })
*/
io.use(function(socket, next) {
  var cookie = socket.handshake.headers.cookie,
      sid = cookie.match(/connect.sid=s%3A([^\.]+)\.*/);

  if (sid)
    sid = sid[1];
  else
    return next('no session', false);
    
  sessionStore.get(sid, function(err, session) {
    if (!session)
      return next('no session', false);
    // check every 5 seconds to see if the express session is active
    var checkSession = setInterval(function() {
      sessionStore.get(sid, function(err, session) {
        if (!session) {
          socket.disconnect(true);
          clearInterval(checkSession);
        }
      });
    }, 5000);
    next();
  });
});

io.of('/io/ping').on('connection', function(socket) {
  setInterval(function() { // emit a pong every 1 sec
    socket.emit('pong', { pong: new Date() });
  }, 1000);
});

io.of('/io/time').on('connection', function(socket) {
  setInterval(function() { // emit a new Date() every .5 sec
    socket.emit('time', new Date());
  }, 500);
});

server.listen(8000);

socket.js

// File: client/scripts/services/socket.js

// Here's the good stuff! =)
// Heavily inspired by another developer's work whom I've lost track of
'use strict';

angular.module('theApp')
  .service('socket', function($rootScope) {

    this.connect = function(namespace) {
      console.log('connecting: ', namespace)
      var _socket = io.connect(namespace);
      _socket._on = _socket.on;
      _socket._emit = _socket.emit;

      _socket.on = function(eventName, callback) {
        _socket._on(eventName, function() {
          var args = arguments;
          $rootScope.$apply(function() {
            callback.apply(_socket, args);
          });
        });
      };

      _socket.emit = function(eventName, data, callback) {
        _socket._emit(eventName, data, function() {
          var args = arguments;
          $rootScope.$apply(function() {
            if (callback) {
              callback.apply(_socket, args);
            }
          });
        });
      };

      return _socket;
    };

  })

I'm struggling with authentication on the socket, if anyone has any ideas for nice, clean solutions, please let me know.

I think I've sorted out the authentication sync between Express & Socket.IO in server.js