public static function domain()
{
$self = self::instance();
if (is_null($self->domain)) {
if (array_key_exists('REQUEST_URI', $_SERVER)) {
$s = array_key_exists('HTTPS', $_SERVER) ? 's' : '';
$self->domain = 'http' . $s . '://' . $_SERVER['HTTP_HOST'];
} else {
$self->domain = 'http://localhost';
}
}
return $self->domain;
}