How do I set USER_ID in Google Universal Analytics tracking code in Rails?

Question

Here's the Universal Analytics tracking code for my Rails-based app. (It can be found in _analytics.html.erb, which is loaded as a partial in application.html.erb)

 <script>
   (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
   (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
   m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
   })(window,document,'script','//www.google-analytics.com/analytics.js','ga'); 

   ga('create', 'UA-44709438-1', 'auto');
   ga('set', '&uid', {{USER_ID}}); // Set the user ID using signed-in user_id.
   ga('send', 'pageview');
 </script>

Question: how do I set USER_ID using Ruby? Is the following right?

 ga('set', '&uid', <% current_user.id %>); // Set the user ID using signed-in user_id.

If not, how can I do this?

Answer 1

As per directive given in google analytics

You should do like this

ga('create', 'UA-XXXX-Y', { 'userId': <%= current_user.id %> })

and link it in application.html.erb exactly before closing of head tag

use this link for reference https://developers.google.com/analytics/devguides/collection/analyticsjs/user-id

Also you may need to add condition to decide whether the user is logged in or not