» Parent-/Eltern-Verzeichnis einer URL ermitteln

function parentdir($url) {
	// note: parent of "/" is "/" and parent of "http://example.com" is "http://example.com/"
	// remove filename and query
	$url = currentdir($url);
	// get parent
	$len = strlen($url);
	return currentdir(substr($url, 0, $len && $url[ $len - 1 ] == '/' ? -1 : $len));
}

parentdir("http://example.com/foo/bar/");

http://example.com/foo/

parentdir(parentdir("http://example.com/foo/bar/index.html"));

http://example.com/

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