passport.socket.io allows your socket.io connections to have access to your passportjs login session.
It will populate the socket.handshake.session.passport.user variable.
// setup express
var express = require('express')
var RedisStore = require('connect-redis')(express);
var redisStore = new RedisStore(); // setup redis
var cookieParser = express.cookieParser('supersecret');
app.configure(function(){
app.use(cookieParser);
app.use(express.session({store: redisStore}));
});
// default socket.io config
var auth = require('passport.socket.io')(cookieParser, redisStore);
io.set('authorization', auth);