A small PHP Script to add usual Google Analytics utm_ variables to outgoing links so you can track your referrers in NATS system. Warning: don't use sever-side page cache with this script

GA_utm_to_Nats_PHP

<?php
/*
A small PHP Script  to add usual Google Analytics utm_ variables to outgoing links so you can track your referrers in NATS system. This works only if NATS has Automatic Campaigns (autocampaigns) enabled:  http://wiki.toomuchmedia.com/index.php/Automatic_Campaigns  tags
NATS 4.1 also supports tags / autotags which can be handy to split utm_ parameters apart

Sample outgoing affil link http://www.affiliate.com/?utm_source=TS&utm_campaign=Header	

author: transbetty@gmail.com, www.transbetty.com

WARNING: don't use sever-side page cache with this script - obviously it will cause the first page visit to generate some  referral the  code, unless you create an exception in your cache (little bit complicated). Use a JS/cookie solution instead: https://gist.github.com/transbetty/ffa7374d8f71667a1e44
*/
	
// if GA utm query var exists, put it into cookie, function setter
function setTrackSource () {
	$my_utm_source =  $_GET['utm_source'];
	$my_utm_campaign =  $_GET['utm_campaign'];
	if ((!empty($my_utm_source) || !empty($my_utm_campaign)) && !(isset($_COOKIE['trackSource'])) ) {
		$autocampValue = $my_utm_source . ",". $my_utm_campaign;
		setcookie('trackSource', $autocampValue, time()+3600*24*30, '/');
		//echo "yes";
	}
}

//output GA utm if present in query var or cookie, function getter
function getTrackSource () {
	$my_utm_source =  $_GET['utm_source'];
	$my_utm_campaign =  $_GET['utm_campaign'];
	if (!empty($my_utm_source) || !empty($my_utm_campaign)) {
		$result = "/?autocamp=".$my_utm_source . ",". $my_utm_campaign;
	} elseif  (isset($_COOKIE['trackSource']) ) {
		$result = "/?autocamp=". $_COOKIE['trackSource'];
	}
	echo $result;
}

setTrackSource ();
getTrackSource();
?>