@Override
public Optional<MqttMessage> process(MqttMessage req, String clientId, String remoteIp) throws BrokerException {
    MqttPublishMessage msg = (MqttPublishMessage) req;
    log.info("PUBLISH, {} Qos: {}", msg.variableHeader().topicName(), msg.fixedHeader().qosLevel());

    switch (msg.fixedHeader().qosLevel()) {
        case AT_MOST_ONCE: {
            this.sessionStore.publishMessage(msg, false);
            return Optional.empty();
        }

        case AT_LEAST_ONCE: {
            boolean result = this.sessionStore.publishMessage(msg, false);
            MqttQoS qos = result ? MqttQoS.AT_LEAST_ONCE : MqttQoS.FAILURE;
            MqttMessage rsp = MqttMessageFactory.newMessage(new MqttFixedHeader(MqttMessageType.PUBACK, false, qos, false, ProtocolProcess.fixLengthOfMessageId),
                    MqttMessageIdVariableHeader.from(msg.variableHeader().packetId()), null);
            return Optional.of(rsp);
        }

        case EXACTLY_ONCE:
        default: {
            log.error("DOT NOT support Qos=2, close");
            throw new BrokerException(ErrorCode.MQTT_NOT_SUPPORT_QOS2);
        }
    }
}
 

@Override
public Optional<MqttMessage> process(MqttMessage req, String clientId, String remoteIp) {
    MqttUnsubscribeMessage msg = (MqttUnsubscribeMessage) req;
    log.info("UNSUBSCRIBE, {}", msg.payload().topics());

    if (msg.payload().topics().isEmpty()) {
        log.error("empty topic, skip it");
        return Optional.empty();
    }

    this.sessionStore.unSubscribe(clientId, msg.payload().topics());

    MqttMessage rsp = MqttMessageFactory.newMessage(new MqttFixedHeader(MqttMessageType.UNSUBACK, false, MqttQoS.AT_LEAST_ONCE, false, ProtocolProcess.fixLengthOfMessageId),
            MqttMessageIdVariableHeader.from(msg.variableHeader().messageId()), null);
    return Optional.of(rsp);
}
 

/**
 *  P - B (Qos2)
 * @param channel
 * @param variableHeader
 */
public void processPubRel(Channel channel, MqttMessageIdVariableHeader variableHeader) {
	int messageId = variableHeader.messageId();
	ProcedureMessage info = this.procedureProcess.processPubRel(channel, messageId);

	if (info != null) {
		NettyLog.debug("relInfo:" + info);

		BorkerMessage bMsgInfo = BorkerMessage.builder().sourceClientId(info.getSourceClientId())
				.sourceMsgId(info.getSourceMsgId()).topicName(info.getTopicName()).iQosLevel(info.getIQosLevel())
				.msgBytes(info.getMsgBytes()).retain(false).build();

		List<SubscribeTopicInfo> subscribeClientList = this.topicProcess.search(bMsgInfo.getTopicName());
		this.consumerProcess.sendSubscribMessage(bMsgInfo, subscribeClientList);
	}

	this.sendProcess.sendPubCompMessage(channel, messageId);
}
 

private void sendPubAck(Channel client, Integer packageID) {
    if (LOG.isDebugEnabled()) {
        LOG.debug("发送PubAck消息给客户端");
    }
    try {
        MqttFixedHeader mqttFixedHeader = new MqttFixedHeader(MqttMessageType.PUBACK, false, MqttQoS.AT_MOST_ONCE, false, 0);
        MqttMessage pubAckMessage = MqttMessageFactory.newMessage(
                mqttFixedHeader,
                MqttMessageIdVariableHeader.from(packageID),
                null);
        client.writeAndFlush(pubAckMessage);
    } catch (Throwable th) {
        LOG.error("Send pubAck error!", th);
        client.close().addListener(CLOSE_ON_FAILURE);
    }
}
 

/**
 * Sends PUBREC packet to server
 *
 * @param publishMessage a PUBLISH message to acknowledge
 */
private void publishReceived(MqttPublishMessage publishMessage) {

  MqttFixedHeader fixedHeader =
    new MqttFixedHeader(MqttMessageType.PUBREC, false, AT_MOST_ONCE, false, 0);

  MqttMessageIdVariableHeader variableHeader =
    MqttMessageIdVariableHeader.from(publishMessage.messageId());

  io.netty.handler.codec.mqtt.MqttMessage pubrec = MqttMessageFactory.newMessage(fixedHeader, variableHeader, null);

  synchronized (this) {
    qos2inbound.put(publishMessage.messageId(), publishMessage);
  }
  this.write(pubrec);
}
 

/**
 * Sends the PUBREL message to server
 *
 * @param publishMessageId  identifier of the PUBLISH message to acknowledge
 */
private void publishRelease(int publishMessageId) {

  MqttFixedHeader fixedHeader =
    new MqttFixedHeader(MqttMessageType.PUBREL, false, MqttQoS.AT_LEAST_ONCE, false, 0);

  MqttMessageIdVariableHeader variableHeader =
    MqttMessageIdVariableHeader.from(publishMessageId);

  io.netty.handler.codec.mqtt.MqttMessage pubrel = MqttMessageFactory.newMessage(fixedHeader, variableHeader, null);

  synchronized (this) {
    qos2outbound.put(publishMessageId, pubrel);
  }
  this.write(pubrel);
}
 

/**
 * B - P (Qos1)
 * @param channel
 * @param mqttMessage
 */
public void processPubAck(Channel channel, MqttMessage mqttMessage) {
	MqttMessageIdVariableHeader messageIdVariableHeader = (MqttMessageIdVariableHeader) mqttMessage
			.variableHeader();
	int messageId = messageIdVariableHeader.messageId();

	producerProcess.processPubAck(messageId);
	producerProcess.delMessage(messageId);
}
 

/**
 * B- P(Qos2)
 * @param channel
 * @param mqttMessage
 */
public void processPubRec(Channel channel, MqttMessage mqttMessage) {
	MqttMessageIdVariableHeader messageIdVariableHeader = (MqttMessageIdVariableHeader) mqttMessage
			.variableHeader();
	int messageId = messageIdVariableHeader.messageId();

	producerProcess.processPubRec(messageId);
	producerProcess.sendPubRel(messageId);
}
 

/**
 * B - P (Qos2)
 * @param channel
 * @param mqttMessage
 */
public void processPubComp(Channel channel, MqttMessage mqttMessage) {
	MqttMessageIdVariableHeader messageIdVariableHeader = (MqttMessageIdVariableHeader) mqttMessage
			.variableHeader();
	int messageId = messageIdVariableHeader.messageId();

	producerProcess.processPubComp(messageId);
	producerProcess.delMessage(messageId);
}
 

/**
 * B - S(Qos2)
 * @param channel
 * @param mqttMessage
 */
public void processPubRel(Channel channel, MqttMessage mqttMessage) {
	MqttMessageIdVariableHeader messageIdVariableHeader = (MqttMessageIdVariableHeader) mqttMessage
			.variableHeader();
	int messageId = messageIdVariableHeader.messageId();
	this.consumerProcess.processPubRel(messageId);
	this.consumerProcess.sendPubCompMessage(messageId);
	this.consumerProcess.delMesage(messageId);
}
 

/**
 * B - S
 * @param channel
 * @param mqttMessage
 */
public void processUnSubBack(Channel channel, MqttMessage mqttMessage) {
	int messageId;
	if (mqttMessage instanceof MqttUnsubAckMessage) {
		MqttUnsubAckMessage mqttUnsubAckMessage = (MqttUnsubAckMessage) mqttMessage;
		messageId = mqttUnsubAckMessage.variableHeader().messageId();
	} else {
		MqttMessageIdVariableHeader o = (MqttMessageIdVariableHeader) mqttMessage.variableHeader();
		messageId = o.messageId();
		NettyLog.error("not UnsubAckMessage:{}", messageId);
	}
	this.consumerProcess.processUnSubBack(messageId);
}
 

public static MqttSubscribeMessage subscribeMessage(List<MqttTopicSubscription> mqttTopicSubscriptions,
		int messageId) {
	MqttSubscribePayload mqttSubscribePayload = new MqttSubscribePayload(mqttTopicSubscriptions);
	MqttFixedHeader mqttFixedHeader = new MqttFixedHeader(MqttMessageType.SUBSCRIBE, false, MqttQoS.AT_LEAST_ONCE,
			false, 0);
	MqttMessageIdVariableHeader mqttMessageIdVariableHeader = MqttMessageIdVariableHeader.from(messageId);
	return new MqttSubscribeMessage(mqttFixedHeader, mqttMessageIdVariableHeader, mqttSubscribePayload);
}
 

public static MqttUnsubscribeMessage unSubscribeMessage(List<String> topic, int messageId) {
	MqttFixedHeader mqttFixedHeader = new MqttFixedHeader(MqttMessageType.UNSUBSCRIBE, false, MqttQoS.AT_MOST_ONCE,
			false, 0x02);
	MqttMessageIdVariableHeader variableHeader = MqttMessageIdVariableHeader.from(messageId);
	MqttUnsubscribePayload mqttUnsubscribeMessage = new MqttUnsubscribePayload(topic);
	return new MqttUnsubscribeMessage(mqttFixedHeader, variableHeader, mqttUnsubscribeMessage);
}
 

public void processPubAck(Channel client, MqttPubAckMessage pubAckMessage) {
    MqttMessageIdVariableHeader pubAckVariableMessage = pubAckMessage.variableHeader();
    short packageId = (short) pubAckVariableMessage.messageId();
    String clientId = NettyAttrManager.getAttrClientId(client);

    consumerManager.acknowledge(clientId, packageId);

    if (LOG.isDebugEnabled()) {
        LOG.debug("Received PubAck packageID: {}" + packageId);
    }
}
 

private void sendUnSubAck(Channel client, int packageID, MqttQoS qoS) {
    MqttFixedHeader mqttFixedHeader = new MqttFixedHeader(MqttMessageType.UNSUBACK, false, qoS, false, 0);
    MqttMessage unSubAckMessage = MqttMessageFactory.newMessage(
            mqttFixedHeader,
            MqttMessageIdVariableHeader.from(packageID),
            null);
    LOG.info("UNSUBSCRIBE successful, packageID: {}", packageID);
    client.writeAndFlush(unSubAckMessage);
}
 

public static MqttPubAckMessage puback(int messageId) {
	MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.PUBACK, false, MqttQoS.AT_MOST_ONCE, false,
			2);
	MqttMessageIdVariableHeader variableHeader = MqttMessageIdVariableHeader.from(messageId);

	return new MqttPubAckMessage(fixedHeader, variableHeader);
}
 

public static MqttMessage pubrec(int messageId) {
	MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.PUBREC, false, MqttQoS.AT_MOST_ONCE, false,
			2);
	MqttMessageIdVariableHeader variableHeader = MqttMessageIdVariableHeader.from(messageId);

	return new MqttMessage(fixedHeader, variableHeader);
}
 

public static MqttMessage pubrel(int messageId) {
	MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.PUBREL, false, MqttQoS.AT_LEAST_ONCE, false,
			2);
	MqttMessageIdVariableHeader variableHeader = MqttMessageIdVariableHeader.from(messageId);

	return new MqttMessage(fixedHeader, variableHeader);
}
 

public static MqttMessage pubcomp(int messageId) {
	MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.PUBCOMP, false, MqttQoS.AT_MOST_ONCE, false,
			2);
	MqttMessageIdVariableHeader variableHeader = MqttMessageIdVariableHeader.from(messageId);

	return new MqttMessage(fixedHeader, variableHeader);
}
 

public static MqttSubscribeMessage subscribe(int messageId, MqttTopicSubscription... topicSubscriptions) {
	int topicNameSize = 0;
	int topicCount = topicSubscriptions.length;

	for (MqttTopicSubscription item : topicSubscriptions) {
		topicNameSize += item.topicName().getBytes(CharsetUtil.UTF_8).length;
	}

	MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.SUBSCRIBE, false, MqttQoS.AT_LEAST_ONCE,
			false, 2 + topicNameSize + topicCount);
	MqttMessageIdVariableHeader variableHeader = MqttMessageIdVariableHeader.from(messageId);
	MqttSubscribePayload payload = new MqttSubscribePayload(Lists.newArrayList(topicSubscriptions));

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

public static MqttSubAckMessage suback(int messageId, List<Integer> grantedQoSLevels) {
	MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.SUBACK, false, MqttQoS.AT_MOST_ONCE, false,
			2 + grantedQoSLevels.size());
	MqttMessageIdVariableHeader variableHeader = MqttMessageIdVariableHeader.from(messageId);
	MqttSubAckPayload payload = new MqttSubAckPayload(grantedQoSLevels);

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

public static MqttUnsubAckMessage unsuback(int messageId) {
	MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.UNSUBACK, false, MqttQoS.AT_MOST_ONCE, false,
			2);
	MqttMessageIdVariableHeader variableHeader = MqttMessageIdVariableHeader.from(messageId);

	return new MqttUnsubAckMessage(fixedHeader, variableHeader);
}
 

@Override
protected void channelRead0(ChannelHandlerContext ctx, MqttMessage msg) throws Exception {
	switch (msg.fixedHeader().messageType()) {
	case PUBLISH:
		if (receiver != null) {
			receiver.messageReceived(Message.newMessage(client.clientId(), (MqttPublishMessage) msg));
		}

		int messageId = ((MqttPublishMessage) msg).variableHeader().messageId();
		if (((MqttPublishMessage) msg).fixedHeader().qosLevel() == MqttQoS.AT_LEAST_ONCE) {
			client.send(MqttMessageFactory.puback(messageId));
		}
		else if (((MqttPublishMessage) msg).fixedHeader().qosLevel() == MqttQoS.EXACTLY_ONCE) {
			client.send(MqttMessageFactory.pubrec(messageId));
		}
		break;

	case CONNACK:
		sharedObject.receivedMessage(msg);

		synchronized (sharedObject.locker()) {
			sharedObject.locker().notify();
		}
		break;

	case PUBREC:
		client.send(MqttMessageFactory.pubrel(((MqttMessageIdVariableHeader) msg.variableHeader()).messageId()));
		break;

	case SUBACK:
	case PUBACK:
	case PUBCOMP:
	default:
		break;
	}
}
 

void sendPublishProtocolControlMessage(int messageId, MqttMessageType messageType) {
   MqttQoS qos = (messageType == MqttMessageType.PUBREL) ? MqttQoS.AT_LEAST_ONCE : MqttQoS.AT_MOST_ONCE;
   MqttFixedHeader fixedHeader = new MqttFixedHeader(messageType, false, qos, // Spec requires 01 in header for rel
                                                     false, 0);
   MqttPubAckMessage rel = new MqttPubAckMessage(fixedHeader, MqttMessageIdVariableHeader.from(messageId));
   sendToClient(rel);
}
 

private MqttMessage genSubAck(int messageId, List<Integer> mqttQoSList) {
    return MqttMessageFactory.newMessage(new MqttFixedHeader(MqttMessageType.SUBACK, false, MqttQoS.AT_LEAST_ONCE, false, ProtocolProcess.fixLengthOfMessageId + mqttQoSList.size()),
            MqttMessageIdVariableHeader.from(messageId),
            new MqttSubAckPayload(mqttQoSList));
}
 

public static int messageId(MqttMessage msg) {
    return ((MqttMessageIdVariableHeader) msg.variableHeader()).messageId();
}
 

/**
 *  S - B (Qos2)
 * @param channel
 * @param variableHeader
 */
public void processPubRec(Channel channel, MqttMessageIdVariableHeader variableHeader) {
	int messageId = variableHeader.messageId();
	this.consumerProcess.processPubRec(channel, messageId);
	this.sendProcess.sendPubRelMessage(channel, messageId, false);
}
 

@Override
protected void channelRead0(ChannelHandlerContext ctx, MqttMessage msg) throws Exception {
	
	if (!msg.decoderResult().isSuccess()) {
		NettyLog.error("error decoder");
		ctx.close(); 
		return;
	}
	
	NettyLog.debug("read: " + msg.fixedHeader().messageType());
	
	if (msg.fixedHeader().messageType() == MqttMessageType.CONNECT) {
		protocolProcess.processConnect(ctx.channel(), (MqttConnectMessage) msg);
	} else {
		if (!NettyUtil.isLogin(ctx.channel())) {
			NettyLog.info("not login");
			return ;
		}
	}

	switch (msg.fixedHeader().messageType()) {
	case CONNECT:
		break;
	case CONNACK:
		break;
	case PUBLISH:
		protocolProcess.processPublish(ctx.channel(), (MqttPublishMessage) msg);
		break;
	case PUBACK:
		protocolProcess.processPubAck(ctx.channel(), (MqttMessageIdVariableHeader) msg.variableHeader());
		break;
	case PUBREC:
		protocolProcess.processPubRec(ctx.channel(), (MqttMessageIdVariableHeader) msg.variableHeader());
		break;
	case PUBREL:
		protocolProcess.processPubRel(ctx.channel(), (MqttMessageIdVariableHeader) msg.variableHeader());
		break;
	case PUBCOMP:
		protocolProcess.processPubComp(ctx.channel(), (MqttMessageIdVariableHeader) msg.variableHeader());
		break;
	case SUBSCRIBE:
		protocolProcess.processSubscribe(ctx.channel(), (MqttSubscribeMessage) msg); 
		break;
	case SUBACK:
		break;
	case UNSUBSCRIBE:
		protocolProcess.processUnSubscribe(ctx.channel(), (MqttUnsubscribeMessage) msg);
		break;
	case UNSUBACK:
		break;
	case PINGREQ:
		protocolProcess.processPingReq(ctx.channel(), msg);
		break;
	case PINGRESP:
		break;
	case DISCONNECT:
		protocolProcess.processDisConnect(ctx.channel(), msg);
		break;
	default:
		break;
	}
}
 

public static MqttUnsubAckMessage unsubAckMessage(int messageId) {
	return (MqttUnsubAckMessage) MqttMessageFactory.newMessage(
			new MqttFixedHeader(MqttMessageType.UNSUBACK, false, MqttQoS.AT_MOST_ONCE, false, 0),
			MqttMessageIdVariableHeader.from(messageId), null);
}
 

public static MqttSubAckMessage subAckMessage(int messageId, List<Integer> mqttQoSList) {
	return (MqttSubAckMessage) MqttMessageFactory.newMessage(
			new MqttFixedHeader(MqttMessageType.SUBACK, false, MqttQoS.AT_MOST_ONCE, false, 0),
			MqttMessageIdVariableHeader.from(messageId), new MqttSubAckPayload(mqttQoSList));
}