php http basic auth

define('HTTP_USER','user');
define('HTTP_PASS','pass');
if(isset($_SERVER['PHP_AUTH_USER'])&&($_SERVER['PHP_AUTH_PW']==HTTP_PASS)&&(strtolower($_SERVER['PHP_AUTH_USER'])==HTTP_USER)){
	//success
}
else{
	header('WWW-Authenticate: Basic realm="Authorization required"');
	header('HTTP/1.0 401 Unauthorized');
	echo 'Authenticate required!';
	exit();
}