Secure variables from outside

// Secure variables from outside
foreach(array('HTTP_REFERER','HTTP_USER_AGENT') as $outside) {
  $_SERVER[$outside] = preg_replace("/[^A-Za-z0-9_\-\,\.\/\s]/", "", $_SERVER[$outside]);
  if(strlen($_SERVER[$outside])>255) $_SERVER[$outside] = substr(0,255,$_SERVER[$outside]);
}
if(isset($_GET['q'])) $_GET['q'] = preg_replace("/[^A-Za-z0-9_\-\.\/]/", "", $_GET['q']);

// Never allow request via get and post contain snippets, javascript or php
$modxtags = array('@<script[^>]*?>.*?</script>@si',
                  '@&#(\d+);@e',
                  '@\[\[(.*?)\]\]@si',
                  '@\[!(.*?)!\]@si',
                  '@\[\~(.*?)\~\]@si',
                  '@\[\((.*?)\)\]@si',
                  '@{{(.*?)}}@si',
                  '@\[\*(.*?)\*\]@si');
foreach($_POST as $key => $value) {
  $_POST[$key] = preg_replace($modxtags,"", $value);
}
foreach($_GET as $key => $value) {
  $_GET[$key] = preg_replace($modxtags,"", $value);
}
// End of modification