$re = '/^(?:(?\'scheme\'http[s]?):\/\/)?(?\'host\'[a-z0-9_\-.]+)(?:\:(?\'port\'[0-9]+))?(?\'path\'\/[^\?\s]*)?(?:\?(?\'query\'\S+))?/m';
$str = 'http://website.host21.ru/contacts?p1=2&p2=3
website.host21.ru/contacts/
https://host1.host21.ru:80/contacts/
http://localhost:5372';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php