$filename = preg_replace('/(?:\.html)?$/', '.html', ltrim($_SERVER['PATH_INFO'], '/'), 1);
if (file_exists($filename) and !is_writable($filename))
abort('403 input error', "ongeldige bestandsnaam: $filename");
$filename = preg_replace('/(?:\.html)?$/', '.html', ltrim($_SERVER['PATH_INFO'], '/'), 1);
if (file_exists($filename) and !is_writable($filename))
abort('403 input error', "ongeldige bestandsnaam: $filename");