universal-analytics wrapper to assist with putting user info on session. Note that this method assumes you are going to scrape the cid out of the _ga cookie i.e. let analytics.js derive the cid and do the cookie persistance for you. If you want to use your own cid determined server side, then this is not for you.

universal-analytics-wrapper.js

/*
Useage

**require**
uaw = require('.[path]/universal-analytics-wrapper'),

** express setup **
app.use(uaw.cookieConfigurer('UAXXXXX'));

** get visitor **
var visitor = uaw.getVisitor(req.session);

** get visitor socket.io with session integration**
var visitor = uaw.getVisitor(socket.handshake.session);

** use visitor **
visitor.debug().event("activation", "Joined Hosted Room").send();

*/


var ua = require('universal-analytics');
var gaTrackingIdlocal;

module.exports.cookieConfigurer = function(gaTrackingId) {
    gaTrackingIdlocal = gaTrackingId;

    return function cookieConfigurer(req, res, next) {
        if(req.session && (!req.session.cid) && req.cookies._ga){
            //Use the cid already embedded in the _ga cookie and save to session
            var gaSplit = req.cookies._ga.split('.');
            req.session.cid = gaSplit[2] + "." + gaSplit[3];
        };
        next();
    }
};

module.exports.getVisitor = function(session){
    console.log('getVisitor');
    if(session && session.cid){
        console.log('gaTrackingIdlocal:' + gaTrackingIdlocal);
        console.log('session.cid:' + session.cid);
        return ua(gaTrackingIdlocal, session.cid);
    }  
}