bool validate(server & s, connection_hdl hdl) {
    server::connection_ptr con = s.get_con_from_hdl(hdl);

    std::cout << "Cache-Control: " << con->get_request_header("Cache-Control") << std::endl;

    const std::vector<std::string> & subp_requests = con->get_requested_subprotocols();
    std::vector<std::string>::const_iterator it;

    for (it = subp_requests.begin(); it != subp_requests.end(); ++it) {
        std::cout << "Requested: " << *it << std::endl;
    }

    if (subp_requests.size() > 0) {
        con->select_subprotocol(subp_requests[0]);
    }

    return true;
}