I see that Google Analytics now allows you to see how many users are currently on your website, does anyone know if this information is accessible via javascript ?
Google provides an example of accessing it's API's via javascript. I haven't seen a javascript solution with a service account although it may be out there. Google APIs Client Library for JS
I did find this post: How to get an access to Google Drive API service account from web browser
You can use a service account to access this data without user interaction (log in authorization) on a ColdFusion server with relative ease.
The Real Time API is in beta now and you must request access: https://developers.google.com/analytics/devguides/reporting/realtime/v3/
After that, you will need to install the .jar files from Google which can be downloaded at Google Analytics API Client Library for Java into the WEB-INF/lib folder of the CF server.
Create the objects in ColdFusion. Here is a single example:
variables.HTTP_Transport = createObject("java", "com.google.api.client.http.javanet.NetHttpTransport").init();
You will then follow the instructions Google has for using the java objects almost exactly.
There are too many lines to list (but it's not too crazy) so you can follow this post: Google Analytics Real Time API Access with Service Account and ColdFusion