Processwire Google Analytics Tracking
<?php
$test_url = "https://ga-dev-tools.appspot.com/hit-builder/";
$http = new WireHttp();
$http->post('http://www.google-analytics.com/collect', [ // Make sure to use HTTP, not HTTPS!
'v' => 1, // Version
'tid' => 'your-tracking-id', // Tracking ID / Property ID.
'cid' => 555, // Anonymous Client ID.
't' => 'event', // hit type
'ec' => 'myEventCategory', // category
'ea' => 'myEventAction', // action
'el' => 'myEventLabel', // label
]);