- parse_str: documentation ( source)
- parse_url: documentation ( source)
<?php
$url = 'http://yoursite.com/?site=http://exapmle.com/&site2=http://google.com/';
$query = parse_url($url, PHP_URL_QUERY );
parse_str($query, $params);
$site = $params['site'];
$sitehost = parse_url($site, PHP_URL_HOST);
echo $sitehost . PHP_EOL;