Evo to Revo URI Plugin

evoURI.plugin.php

<?php
/**
 ** OnPageNotFound
**/

$URI = $_SERVER['REQUEST_URI'];

if(strpos($URI, '.html') !== false){
    $URI = ltrim(str_replace('.html','/',$URI), '/');
    $resource = $modx->getObject('modResource', array('uri:='=>$URI, 'context_key:='=> $modx->context->key));
    if(!empty($resource)){
        $modx->sendRedirect($modx->makeUrl($resource->id, $modx->context->key, '', 'full'), 0, 'REDIRECT_HEADER', 'HTTP/1.1 301 Moved Permanently');
    }
}else{
    $URI = ltrim($URI, '/').'.html';
    $resource = $modx->getObject('modResource', array('uri:='=>$URI, 'context_key:='=> $modx->context->key));
    if(!empty($resource)){
       $modx->sendRedirect($modx->makeUrl($resource->id, $modx->context->key, '', 'full'), 0, 'REDIRECT_HEADER', 'HTTP/1.1 301 Moved Permanently');
    }
}