inline CSS snippet for MODX Revolution

inline.php

<?php
// [[!inline?&file=`css/critical.css`]]
$assetsPath = $modx->getOption('assets_path');
$file = !empty($file) ? $file : $modx->getOption('file', $scriptProperties, '');
$myfile = fopen($assetsPath . $file, "r");

if (!$myfile){ return "";}
$inlneCSS = "";

while(!feof($myfile)) {
  $inlneCSS .= fgets($myfile);
}

fclose($myfile);
return $inlneCSS;