[krapp]

PHP already has a filter (FILTER_VALIDATE_URL) for validating urls using filter_var[0], however, it doesn't work on international URLs. You can also break up a url with parse_url()[1]

You might also want to look into PHP's curl wrapper which is a lot more powerful[2].

[0]https://secure.php.net/manual/en/function.filter-var.php

[1]https://secure.php.net/manual/en/function.parse-url.php

[2]https://secure.php.net/manual/en/book.curl.php