PHP functions to send data to Google Analytics

server-side-ga-events.php

//Parse the GA Cookie
function gaParseCookie() {
	if (isset($_COOKIE['_ga'])) {
		list($version, $domainDepth, $cid1, $cid2) = explode('.', $_COOKIE["_ga"], 4);
		$contents = array('version' => $version, 'domainDepth' => $domainDepth, 'cid' => $cid1 . '.' . $cid2);
		$cid = $contents['cid'];
	} else {
		$cid = gaGenerateUUID();
	}
	return $cid;
}

//Generate UUID
//Special thanks to stumiller.me for this formula.
function gaGenerateUUID() {
	return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
		mt_rand(0, 0xffff), mt_rand(0, 0xffff),
		mt_rand(0, 0xffff),
		mt_rand(0, 0x0fff) | 0x4000,
		mt_rand(0, 0x3fff) | 0x8000,
		mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
	);
}

//Send Data to Google Analytics
//https://developers.google.com/analytics/devguides/collection/protocol/v1/devguide#event
function gaSendData($data) {
	$getString = 'https://ssl.google-analytics.com/collect';
	$getString .= '?payload_data&';
	$getString .= http_build_query($data);
	$result = wp_remote_get($getString);
	return $result;
}

//Send Pageview Function for Server-Side Google Analytics
function ga_send_pageview($hostname=null, $page=null, $title=null) {
	$data = array(
		'v' => 1,
		'tid' => 'UA-000000-1', //@TODO: Change this to your Google Analytics Tracking ID.
		'cid' => gaParseCookie(),
		't' => 'pageview',
		'dh' => $hostname, //Document Hostname "gearside.com"
		'dp' => $page, //Page "/something"
		'dt' => $title //Title
	);
	gaSendData($data);
}

//Send Event Function for Server-Side Google Analytics
function ga_send_event($category=null, $action=null, $label=null) {
	$data = array(
		'v' => 1,
		'tid' => 'UA-000000-1', //@TODO: Change this to your Google Analytics Tracking ID.
		'cid' => gaParseCookie(),
		't' => 'event',
		'ec' => $category, //Category (Required)
		'ea' => $action, //Action (Required)
		'el' => $label //Label
	);
	gaSendData($data);
}