// hack for https proxies
        if (isset($_SERVER['HTTP_X_FORWARDED_PROTO'])) {
            if ($_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https' && isset($_SERVER['SERVER_PORT']) && in_array($_SERVER['SERVER_PORT'], [80, 82])) { // https over proxy
                $_SERVER['HTTPS'] = 'On';
                $_SERVER['SERVER_PORT'] = 443;

            } elseif ($_SERVER['HTTP_X_FORWARDED_PROTO'] === 'http' && isset($_SERVER['SERVER_PORT']) && $_SERVER['SERVER_PORT'] == 80) { // http over proxy
                $_SERVER['HTTPS'] = 'Off';
                $_SERVER['SERVER_PORT'] = 80;
            }

        } elseif (isset($_SERVER['SERVER_PORT']) && $_SERVER['SERVER_PORT'] == 81) { // spdy
            $_SERVER['HTTPS'] = 'On';
            $_SERVER['SERVER_PORT'] = 443;
        }