drupal php check valid url
A too-simple snippet contributed elsewhere:
<?php
function valid_url($str)
{
return ( ! preg_match('/^(http|https|ftp):\/\/([A-Z0-9][A-Z0-9_-]*(?:\.[A-Z0-9][A-Z0-9_-]*)+):?(\d+)?\/?/i', $str)) ? FALSE : TRUE;
}
?>
After following this epic thread
http://drupal.org/node/124492
it becomes clear that Drupal has a wonderful valid_url function of its own, thanks to mfer