Plugin to fix trailing slash inconsistencies in MODX Resource URIs

NormalizeUriSuffix.plugin.php

<?php
/**
 * Steps to implement
 * 1. Set HTML content-type default suffix to '/'
 * 2. Ensure Resources have isFolder = 1 as default
 * 3. If you still have issues with Resources being routed to the URI without a trailing slash,
 *    create this Plugin and enable it 'OnWebPageInit'.
 **/
if ($modx->event->name !== 'OnWebPageInit') return;
if (substr($_SERVER['REQUEST_URI'], -1) !== '/') $modx->sendRedirect($_SERVER['REQUEST_URI'] . '/', array(
    'responseCode' => 'HTTP/1.1 301 Moved Permanently'));