modx switch context by url

<?php
if ($modx->context->get('key') == 'mgr') return;
if (!function_exists('contextbyurl_error_handler')) {
  function contextbyurl_error_handler($errno, $errstr) {
	  global $modx;
	  $modx->log(E_ERROR, $errstr);
  }
}
$conditions = $modx->getCollection('modContextSetting', array('key' => 'condition.regex'));
set_error_handler('contextbyurl_error_handler');
foreach($conditions as $cn) {
	if ($cn) {
		$condition = $cn->toArray();
		if (preg_match($condition['value'], $_SERVER['REQUEST_URI']) > 0) {
		  $modx->switchContext($condition['context_key']);
		  return;
		}			
	}
}
restore_error_handler();