$re = '/^(https?|ftp):\/\/(?!\W*www\.)\S+$/m';
$str = 'http://example.com
http://example.com/path1/path2?hello=1&hello=2
http://a
http://abc
http:/example.com
http://exampl e.com
http:// exampl e.com
http://example.com // Trailing space
http:// example.com
http:///www.example.com';
preg_match_all($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