CONNECT Packet Structure CONNACK Packet Structure Conclusion In Introduction to MQTT 5.0 Packet, we introduced that MQTT packets are composed of three parts: Fixed Header, Variable Header, and Payload, as well as common concepts in MQTT packets such as Variable Byte Integer and Property. Now, we...
UNSUBSCRIBE Packet Structure Fixed Header Same as the SUBSCRIBE packet, the only difference is that the value of the Packet Type field changes from 8 (0b1000) to 10 (0b1010). Variable Header Same as the SUBSCRIBE packet. Payload The payload of the UNSUBSCRIBE packet contains one or more To...
1、数据结构体 (1)MQTT包 /** Network write buffers for an MQTT packet*/typedefstruct{intcount;/**> number of buffers/buflens/frees */char**buffers;/**> array of byte buffers */size_t*buflens;/**> array of lengths of buffers */int*frees;/**> array of flags indicating whether eac...
{ MQTT_PACKET_STRUCTURE mqttPacket = {NULL, 0, 0, 0}; //协议包 char buf[128]; short body_len = 0, i = 0; UsartPrintf(USART_DEBUG, "Tips: OneNet_SendData-MQTT\r\n"); memset(buf, 0, sizeof(buf)); body_len = OneNet_FillBuf(buf); //获取当前需要发送的数据流的总长度 if(bod...
2.1 MQTT控制报文的结构 Structure of an MQTT Control Packet 2.2 固定报头 Fixed header 2.2.1 MQTT控制报文的类型 MQTT Control Packet type 2.2.2 标志 Flags 控制报文字类型是从值区分为0-15依次对应 Reserved Connect ConnAck Publish PubRec PubComp Subscribe SubAck Unsubscribe PingReq PingResp DisConnect ...
MQTT通过交换一些预定义的MQTT控制包来工作。这一节描述这些包的格式。 一个MQTT控制包包含三部分,按照下图的顺序Figure 2.1 - Structure of an MQTT Control Packet. Figure2.1-StructureofanMQTTControlPacket|固定包头,存在于所有MQTT控制包 |可变包头,存在于某些MQTT控制包 ...
(const int8 *user, const int8 *password, const int8 *devid, uint16 cTime, uint1 clean_session, uint1 qos, const int8 *will_topic, const int8 *will_msg, int32 will_retain, MQTT_PACKET_STRUCTURE *mqttPacket) { uint8 flags = 0; uint8 will_topic_len = 0; uint16 total_len = ...
{ MQTT_PACKET_STRUCTURE mqttPacket = {NULL, 0, 0, 0}; unsigned char sCount = 3; //---步骤一:组包--- if(MQTT_PacketPing(&mqttPacket)) return; while(sCount--) { //---步骤二:发送数据---
2.1 MQTT控制报文的结构 Structure of an MQTT Control PacketMQTT协议通过交换预定义的MQTT控制报文来通信。这一节描述这些报文的格式。MQTT控制报文由三部分组成,按照 图例2.1 –MQTT控制报文的结构 描述的顺序:图例2.1 –MQTT控制报文的结构Fixed header固定报头,所有控制报文都包含 Variable header 可变报头,部分控制...
2.1 MQTT控制报文的结构 Structure of an MQTT Control PacketMQTT协议通过交换预定义的MQTT控制报文来通信。这一节描述这些报文的格式。MQTT控制报文由三部分组成,按照 图例2.1 –MQTT控制报文的结构 描述的顺序:图例2.1 –MQTT控制报文的结构Fixed header固定报头,所有控制报文都包含 Variable header 可变报头,...