$re = '/^(?:(?<protocol>[a-z]+):\/\/)?
(?:(?:(?<username>[^@\r\n:]+))
(?::(?<password>[^@\r\n]+))?@)?
(?<host>[^\/:\r\n]+)
(?::(?<port>\d+))?
(?:\/(?<path>[^?\r\n]+)?)?
(?:\?(?<query>[^\r\n]+))?/xm';
$str = 'http://server:12345/path/blabla
http://server.com:1234/path?query_string#fragment_id
ftp://user:password@server:1234/path
ftp://user@server:1234/path
http://www.server.com
www.server.com/path
server.com
http://user@server.com:1234/path?query_string#fragment_id
user@server.com:1234
';
preg_match_all($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