Domain ohne www auf mit umleiten in PHP

// redirect *example.org to www.*example.org
if ($_SERVER['SERVER_NAME']{0} . $_SERVER['SERVER_NAME']{1} . $_SERVER['SERVER_NAME']{2} . $_SERVER['SERVER_NAME']{3} != 'www.') {
	header('HTTP/1.1 301 Moved Permanently');
	header('Location: http://www.' . $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI']);
	exit;
}

// redirect www.*example.org to *example.org
if ($_SERVER['SERVER_NAME']{0} . $_SERVER['SERVER_NAME']{1} . $_SERVER['SERVER_NAME']{2} . $_SERVER['SERVER_NAME']{3} == 'www.') {
	header('HTTP/1.1 301 Moved Permanently');
	header('Location: http://' . $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI']);
	exit;
}

// redirect example.org to www.example.org
if ($_SERVER['SERVER_NAME'] == 'example.org') {
	header('HTTP/1.1 301 Moved Permanently');
	header('Location: http://www.' . $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI']);
	exit;
}

// redirect www.example.org to example.org
if ($_SERVER['SERVER_NAME'] == 'www.example.org') {
	header('HTTP/1.1 301 Moved Permanently');
	header('Location: http://' . substr($_SERVER['SERVER_NAME'], 4) . $_SERVER['REQUEST_URI']);
	exit;
}