こんな機能が欲しい

$referer = isset($_SERVER['HTTP_REFERER'])? urldecode($_SERVER['HTTP_REFERER']): '';
if(!empty($referer)) {
	$pieces = parse_url($referer);
	$referer = $pieces['scheme']."://".$pieces['host'].$pieces['path'];
	if(strpos($referer, $_SERVER['SERVER_NAME'])<1) {
		$pieces['path'] から検索文字列の抽出
	}
}

$limit=いくつ分取り出すか;
$sql = "SELECT t2.data AS referer FROM ".$modx->getFullTableName('log_access')." AS t1, ".$modx->getFullTableName('log_referers')." AS t2 WHERE t1.document = ".$modx->documentIdentifier." AND t1.referer = t2.id AND t2.data!='Unknown' AND t2.data!='Internal' GROUP BY referer ORDER BY t1.timestamp DESC LIMIT ".$limit;
$result = $modx->dbQuery($sql);
$count = $modx->recordCount($result);
for ($i=0;$i<$count;$i++) {
    $row = $modx->fetchRow($result);
    $row['referer']から検索文字列の抽出
}