public static MqttConnectMessage connect(ConnectOptions options) {
	MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.CONNECT, false, MqttQoS.AT_MOST_ONCE, false,
			10);
	MqttConnectVariableHeader variableHeader = new MqttConnectVariableHeader(options.version().protocolName(),
			options.version().protocolLevel(), options.userName() != null, options.password() != null,
			options.will() == null ? false : options.will().isRetain(),
			options.will() == null ? 0 : options.will().qos().value(), options.will() != null,
			options.cleanSession(), options.keepAliveTimeSeconds());

	MqttConnectPayload payload = new MqttConnectPayload(Strings.nullToEmpty(options.clientId()),
			options.will() == null ? "" : options.will().topicName(),
			options.will() == null ? "" : new String(options.will().message(), CharsetUtil.UTF_8),
			Strings.nullToEmpty(options.userName()), Strings.nullToEmpty(options.password()));

	return new MqttConnectMessage(fixedHeader, variableHeader, payload);
}
 

private MqttConnAckMessage executeNormalChannelRead0(String clientId, boolean cleanSession, ChannelId channelId)
		throws Exception {
	MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.CONNECT, false, MqttQoS.AT_MOST_ONCE, false,
			10);
	MqttConnectVariableHeader variableHeader = new MqttConnectVariableHeader("MQTT", 4, true, true, true, 0, true,
			cleanSession, 60);
	MqttConnectPayload payload = new MqttConnectPayload(clientId, "willtopic", "willmessage", "username",
			"password");

	MqttConnectMessage msg = new MqttConnectMessage(fixedHeader, variableHeader, payload);

	ChannelId cid = channelId == null ? TestUtil.newChannelId(clientId, false) : channelId;

	EmbeddedChannel channel = new EmbeddedChannel(cid, new ConnectReceiver());

	channel.writeInbound(msg);

	return channel.readOutbound();
}
 

public static MqttConnectMessage connectMessage(MqttConnectOptions info) {
	MqttVersion verinfo = info.getMqttVersion();
	MqttFixedHeader mqttFixedHeader = new MqttFixedHeader(MqttMessageType.CONNECT, false, MqttQoS.AT_MOST_ONCE,
			false, 10);
	MqttConnectVariableHeader mqttConnectVariableHeader = new MqttConnectVariableHeader(verinfo.protocolName(),
			verinfo.protocolLevel(), info.isHasUserName(), info.isHasPassword(), info.isHasWillRetain(),
			info.getWillQos(), info.isHasWillFlag(), info.isHasCleanSession(), info.getKeepAliveTime());
	MqttConnectPayload mqttConnectPayload = new MqttConnectPayload(info.getClientIdentifier(), info.getWillTopic(),
			info.getWillMessage(), info.getUserName(), info.getPassword());
	MqttConnectMessage mqttSubscribeMessage = new MqttConnectMessage(mqttFixedHeader, mqttConnectVariableHeader,
			mqttConnectPayload);
	return mqttSubscribeMessage;
}
 

private MqttMessage createConnectPacket(MqttClientOptions options) {
  MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.CONNECT,
    false,
    MqttQoS.AT_MOST_ONCE,
    false,
    0);

  MqttConnectVariableHeader variableHeader = new MqttConnectVariableHeader(
    PROTOCOL_NAME,
    PROTOCOL_VERSION,
    options.hasUsername(),
    options.hasPassword(),
    options.isWillRetain(),
    options.getWillQoS(),
    options.isWillFlag(),
    options.isCleanSession(),
    options.getKeepAliveTimeSeconds()
  );

  MqttConnectPayload payload = new MqttConnectPayload(
    options.getClientId() == null ? "" : options.getClientId(),
    options.getWillTopic(),
    options.getWillMessage() != null ? options.getWillMessage().getBytes(StandardCharsets.UTF_8) : null,
    options.hasUsername() ? options.getUsername() : null,
    options.hasPassword() ? options.getPassword().getBytes(StandardCharsets.UTF_8) : null
  );

  return MqttMessageFactory.newMessage(fixedHeader, variableHeader, payload);
}