This is a very basic MediaWiki extension that exposes the PHP parse_url functions.

http://php.net/manual/en/function.parse-url.php

Usage

{{#parseurl: http://www.youtube.com/watch?v=C4kxS1ksqtw&feature=relate | host}}

Returns www.youtube.com

{{#parseurl: http://www.youtube.com/watch?v=C4kxS1ksqtw&feature=relate | scheme}}

Returns http

{{#parseurl: http://www.youtube.com/watch?v=C4kxS1ksqtw&feature=relate | path}}

Returns /watch

{{#parseurl: http://www.youtube.com/watch?v=C4kxS1ksqtw&feature=relate | query}}

Returns v=C4kxS1ksqtw&feature=relate

{{#parseurl: http://username:password@hostname/path?arg=value#anchor | fragment}}

Returns anchor

{{#parseurl: http://username:password@hostname/path?arg=value#anchor | anchor}}

Returns nothing.

{{#parseurlquery: http://www.youtube.com/watch?v=C4kxS1ksqtw&feature=relate | v}}

Returns C4kxS1ksqtw

{{#parseurlquery: http://www.youtube.com/watch?v=C4kxS1ksqtw&feature=relate | bar}}

Returns nothing.