//请求连接
void mqtt_connect(char *clientid,char *username,char *passwd)
{uint32_t clientid_len = strlen(clientid);uint32_t username_len = strlen(username);uint32_t passwd_len = strlen(passwd);//用于存储剩余长度 = 可变包头+有效载荷(客户端id+2+用户名+2+密码+2);uint32_t remain_len = 10 + (clientid_len+2)+ (username_len+2)+ (passwd_len+2);//1 对发送缓冲区进行初始化memset((char *)sendbuf,0,512);sendcnt = 0;//2 固定包头sendbuf[sendcnt++] = 0x10;//connect//3 对剩余长度进行编码do{uint8_t encodeByte = remain_len %128;remain_len = remain_len /128;if(remain_len >0){encodeByte = encodeByte |128;}sendbuf[sendcnt++] = encodeByte;}while(remain_len >0);//4 可变包头sendbuf[sendcnt++] = 0;sendbuf[sendcnt++] = 4;sendbuf[sendcnt++] = 'M';//协议名称sendbuf[sendcnt++] = 'Q';sendbuf[sendcnt++] = 'T';sendbuf[sendcnt++] = 'T';sendbuf[sendcnt++] = 4;//协议版本sendbuf[sendcnt++] = 0xc2 ;//连接标志sendbuf[sendcnt++] = 0 ;//保持连接sendbuf[sendcnt++] = 120 ;//2分钟//5 有效载荷 客户端id 用户名 密码sendbuf[sendcnt++] = BYTE1(clientid_len); //msbsendbuf[sendcnt++] = BYTE0(clientid_len); //lsbmemcpy(&sendbuf[sendcnt] ,clientid,clientid_len);sendcnt +=clientid_len;sendbuf[sendcnt++] = BYTE1(username_len); //msbsendbuf[sendcnt++] = BYTE0(username_len); //lsbmemcpy(&sendbuf[sendcnt] ,username,username_len);sendcnt +=username_len;sendbuf[sendcnt++] = BYTE1(passwd_len); //msbsendbuf[sendcnt++] = BYTE0(passwd_len); //lsbmemcpy(&sendbuf[sendcnt] ,passwd,passwd_len);sendcnt +=passwd_len;//6 把connect报文发送出去Serial_Sendstring(sendbuf,sendcnt);
}
//发布消息
void mqtt_publish(char *topic,uint8_t Qos,char *databuf)
{uint32_t remain_len;uint32_t topic_len = strlen(topic);uint32_t databuf_len = strlen(databuf);//有效载荷//用于存储剩余长度 = 可变包头+有效载荷(客户端id+2+用户名+2+密码+2);if(Qos == 0){remain_len = (topic_len+2)+(databuf_len);}else{remain_len = (topic_len+2)+(databuf_len) + 2;}//1 对发送缓冲区进行初始化memset((char *)sendbuf,0,512);sendcnt = 0;//2 固定包头sendbuf[sendcnt++] = 0x30;//connect//3 对剩余长度进行编码do{uint8_t encodeByte = remain_len %128;remain_len = remain_len /128;if(remain_len >0){encodeByte = encodeByte |128;}sendbuf[sendcnt++] = encodeByte;}while(remain_len >0);//可变包头sendbuf[sendcnt++] = BYTE1(topic_len); //msbsendbuf[sendcnt++] = BYTE0(topic_len); //lsbmemcpy(&sendbuf[sendcnt] ,topic,topic_len);sendcnt +=topic_len;//有效载荷
// sendbuf[sendcnt++] = BYTE1(databuf_len); //msb
// sendbuf[sendcnt++] = BYTE0(databuf_len); //lsbmemcpy(&sendbuf[sendcnt] ,databuf,databuf_len);sendcnt +=databuf_len;//6 把connect报文发送出去Serial_Sendstring(sendbuf,sendcnt);
}
//订阅消息
void mqtt_subscribe(const char *Filter, uint16_t msg_id, uint8_t qos)
{char data[256] = {0};int cnt = 0;uint32_t remain;// 固定包头data[cnt++] = 0x82; // 订阅消息类型// 计算剩余字节长度uint32_t Filter_len = strlen(Filter);remain = 2 + Filter_len + 2 + 1; // 消息 ID (2 字节) + 主题长度 (2 字节) + 主题 (Filter_len 字节) + QoS (1 字节)// 编码剩余字节do{uint8_t encodeByte = remain % 128;remain = remain / 128;if (remain > 0){encodeByte |= 128;}data[cnt++] = encodeByte;}while (remain > 0);// 可变包头data[cnt++] = BYTE1(msg_id); // 消息 ID 高字节data[cnt++] = BYTE0(msg_id); // 消息 ID 低字节// 有效载荷data[cnt++] = BYTE1(Filter_len); // 主题长度高字节data[cnt++] = BYTE0(Filter_len); // 主题长度低字节memcpy(&data[cnt], Filter, Filter_len); // 主题cnt += Filter_len;data[cnt++] = qos; // QoS 级别// 发送构建的 MQTT 消息Serial_Sendstring(data, cnt);
}
//保持心跳请求
void mqtt_keepalive()
{uint8_t buf[2] = {0xc0,0x00};}