php getUser php handle opendir while false file readdir handle if preg

<?php
//getUser.php
$handle = opendir('.');
while (false !== ($file = readdir($handle)))
	if(preg_match('/\.txt$/', $file))
    	if(file_get_contents($file) == $_GET['key']) {
			echo reset(explode('.', $file));
            break;
        }
closedir($handle);