PHP to HTML

index.php

<?php

$base_path = dirname(__FILE__) . '/content/';

if($_GET['q']) {
  $q = explode('?', $_GET['q']);
  $file_check = $base_path.preg_replace('"\.html$"', '.php', $q[0]);
  if (substr($file_check, -1) == "/") {
    $file_check .= "index.php";
  }
  if (@file_exists($file_check)) {
    include_once($file_check);
  } else {
    http_response_code(404);
    die();
  }
} else {
  http_response_code(404);
  die();
}