lib::error_code process_handshake(request_type const & req,
        std::string const & subprotocol, response_type & res) const
    {
        std::array<char, 16> key_final;

        // copy key1 into final key
        decode_client_key(req.get_header("Sec-WebSocket-Key1"), &key_final[0]);

        // copy key2 into final key
        decode_client_key(req.get_header("Sec-WebSocket-Key2"), &key_final[4]);

        // copy key3 into final key
        // key3 should be exactly 8 bytes. If it is more it will be truncated
        // if it is less the final key will almost certainly be wrong.
        // TODO: decide if it is best to silently fail here or produce some sort
        //       of warning or exception.
        const std::string& key3 = req.get_header("Sec-WebSocket-Key3");
        auto sz = std::min(size_t(8), key3.size());
        std::copy(key3.begin(),
                  key3.begin() + sz,
                  key_final.begin() + 8);

        res.append_header(
            "Sec-WebSocket-Key3",
            md5::md5_hash_string(std::string(key_final.begin(), key_final.end()))
        );

        res.append_header("Upgrade","WebSocket");
        res.append_header("Connection","Upgrade");

        // Echo back client's origin unless our local application set a
        // more restrictive one.
        if (res.get_header("Sec-WebSocket-Origin") == "") {
            res.append_header("Sec-WebSocket-Origin",req.get_header("Origin"));
        }

        // Echo back the client's request host unless our local application
        // set a different one.
        if (res.get_header("Sec-WebSocket-Location") == "") {
            uri_ptr uri = get_uri(req);
            res.append_header("Sec-WebSocket-Location",uri->str());
        }

        if (subprotocol != "") {
            res.replace_header("Sec-WebSocket-Protocol",subprotocol);
        }

        return lib::error_code();
    }

    /**
     * @param req The original request sent
     * @param res The reponse to generate
     * @return An error code, 0 on success, non-zero for other errors
     */
    lib::error_code validate_server_handshake_response(request_type const & req,
        response_type& res) const
    {
        // A valid response has an HTTP 101 switching protocols code
        if (res.get_status_code() != http::status_code::switching_protocols) {
            return error::make_error_code(error::invalid_http_status);
        }

        // And the upgrade token in an upgrade header
        std::string const & upgrade_header = res.get_header("Upgrade");
        if (utility::ci_find_substr(upgrade_header, constants::upgrade_token,
            sizeof(constants::upgrade_token)-1) == upgrade_header.end())
        {
            return error::make_error_code(error::missing_required_header);
        }

        // And the websocket token in the connection header
        std::string const & con_header = res.get_header("Connection");
        if (utility::ci_find_substr(con_header, constants::connection_token,
            sizeof(constants::connection_token)-1) == con_header.end())
        {
            return error::make_error_code(error::missing_required_header);
        }

        // And has a valid Sec-WebSocket-Accept value
        std::string key = req.get_header("Sec-WebSocket-Key");
        lib::error_code ec = process_handshake_key(key);

        if (ec || key != res.get_header("Sec-WebSocket-Accept")) {
            return error::make_error_code(error::missing_required_header);
        }

        return lib::error_code();
    }

    request_type (request_type & packet)
    {
      setPCode (packet.getPCode ());
      server_flag = packet.server_flag;
      area = packet.area;

      key.clone (packet.key);
    }

    lib::error_code extract_subprotocols(request_type const & req,
        std::vector<std::string> & subprotocol_list)
    {
        if (!req.get_header("Sec-WebSocket-Protocol").empty()) {
            http::parameter_list p;

             if (!req.get_header_as_plist("Sec-WebSocket-Protocol",p)) {
                 http::parameter_list::const_iterator it;

                 for (it = p.begin(); it != p.end(); ++it) {
                     subprotocol_list.push_back(it->first);
                 }
             } else {
                 return error::make_error_code(error::subprotocol_parse_error);
             }
        }
        return lib::error_code();
    }

    lib::error_code validate_handshake(request_type const & r) const {
        if (r.get_method() != "GET") {
            return make_error_code(error::invalid_http_method);
        }

        if (r.get_version() != "HTTP/1.1") {
            return make_error_code(error::invalid_http_version);
        }

        // required headers
        // Host is required by HTTP/1.1
        // Connection is required by is_websocket_handshake
        // Upgrade is required by is_websocket_handshake
        if (r.get_header("Sec-WebSocket-Key") == "") {
            return make_error_code(error::missing_required_header);
        }

        return lib::error_code();
    }

    uri_ptr get_uri(request_type const & request) const {
        std::string h = request.get_header("Host");

        size_t last_colon = h.rfind(":");
        size_t last_sbrace = h.rfind("]");

        // no : = hostname with no port
        // last : before ] = ipv6 literal with no port
        // : with no ] = hostname with port
        // : after ] = ipv6 literal with port

        if (last_colon == std::string::npos ||
            (last_sbrace != std::string::npos && last_sbrace > last_colon))
        {
            return uri_ptr(new uri(base::m_secure, h, request.get_uri()));
        } else {
            return uri_ptr(new uri(base::m_secure,
                                   h.substr(0,last_colon),
                                   h.substr(last_colon+1),
                                   request.get_uri()));
        }

        // TODO: check if get_uri is a full uri
    }

    lib::error_code client_handshake_request(request_type& req, uri_ptr uri,
            std::vector<std::string> const & subprotocols) const
    {
        req.set_method("GET");
        req.set_uri(uri->get_resource());
        req.set_version("HTTP/1.1");

        req.append_header("Upgrade", "websocket");
        req.append_header("Connection", "Upgrade");
        req.replace_header("Sec-WebSocket-Version", "13");
        req.replace_header("Host", uri->get_host_port());

        if (!subprotocols.empty())
        {
            std::ostringstream result;
            std::vector<std::string>::const_iterator it = subprotocols.begin();
            result << *it++;
            while (it != subprotocols.end())
            {
                result << ", " << *it++;
            }

            req.replace_header("Sec-WebSocket-Protocol", result.str());
        }

        // Generate handshake key
        frame::uint32_converter conv;
        unsigned char raw_key[16];

        for (int i = 0; i < 4; i++)
        {
            conv.i = m_rng();
            std::copy(conv.c, conv.c + 4, &raw_key[i * 4]);
        }

        req.replace_header("Sec-WebSocket-Key", base64_encode(raw_key, 16));

        return lib::error_code();
    }

    /* TODO: the 'subprotocol' parameter may need to be expanded into a more
     * generic struct if other user input parameters to the processed handshake
     * are found.
     */
    lib::error_code process_handshake(request_type const & request, 
        std::string const & subprotocol, response_type & response) const
    {
        std::string server_key = request.get_header("Sec-WebSocket-Key");

        lib::error_code ec = process_handshake_key(server_key);

        if (ec) {
            return ec;
        }

        response.replace_header("Sec-WebSocket-Accept",server_key);
        response.append_header("Upgrade",constants::upgrade_token);
        response.append_header("Connection",constants::connection_token);

        if (!subprotocol.empty()) {
            response.replace_header("Sec-WebSocket-Protocol",subprotocol);
        }

        return lib::error_code();
    }

			void prepare_request(request_type &packet) {
				set_state(has_request);
				payload_length_ = packet.get_payload_length();
				buffer_ = packet.get_buffer();
			}

			void prepare_request(request_type &packet) {
				set_state(has_request);
				buffer_  = packet.write();
			}