MODx evolution 404 snippet for 301 redirects

404-301-redirects.php

<?php

$redirects = array(
  'www.domain.com/old-url-1' => 'www.domain.com/new-url-1',
  'www.domain.com/old-url-2' => 'www.domain.com/new-url-2',
  );

$host = $_SERVER['HTTP_HOST'];

$url_parts = explode('?', $_SERVER['REQUEST_URI']);
$url_to_lookup = $host . $url_parts[0];

$new_url = isset($redirects[$url_to_lookup]) ? $redirects[$url_to_lookup] : null;

if( $new_url !== null ) {
  header ('HTTP/1.1 301 Moved Permanently');
  header ('Location: http://' . $new_url);
}