STM32F1网络编程-MQTT客户端（基于W5500网卡）

MQTT客户端（基于W5500网卡）

MQTT 是用于物联网 (IoT) 的 OASIS 标准消息传递协议。它被设计为一种极其轻量级的发布/订阅消息传输，非常适合连接具有小代码足迹和最小网络带宽的远程设备。如今，MQTT 被广泛用于各种行业，例如汽车、制造、电信、石油和天然气等。

W5500驱动支持MQTT客户端。本次实例将演示如何使用MQTT客户端。

MQTT客户端的主要使用步骤如下：

1）初始化Network对象，并连接Network
2）初始化MQTTClient对象
3）创建MQTT连接
4）订阅主题
5）发布主题

注意：在连接Network时，如MQTT服务器使用的是域名而不是IP地址，则需要使用DNS客户端查询MQTT服务器的IP地址。

关于W5500的驱动移植及IP设置、获取，请参考：

关于TCP通信过程，请参考：

关于远程主机IP查询，请参考：

STM32F1网络编程-DNS客户端查询域名IP地址（基于W5500网卡）

本次使用的MQTT服务器为：https://mosquitto.org/

1、MQTT客户端

在STM32CubeIDE工程的Application目录下分别添加mqtt_client_demo.h和mqtt_client_demo.c文件。其内容分别如下：

/\*
 \* mqtt\_client\_demo.h
 \*
 \* Created on: 2022年7月18日
 \* Author: jenson
 \*/

#ifndef MQTT\_CLIENT\_DEMO\_H\_
#define MQTT\_CLIENT\_DEMO\_H\_

void mqtt\_client\_init(void);
void mqtt\_client\_loop(void);

#endif /\* MQTT\_CLIENT\_DEMO\_H\_ \*/

/\*
 \* mqtt\_client\_demo.c
 \*
 \* Created on: 2022年7月18日
 \* Author: jenson
 \*/
#include "app\_config.h"
#ifdef MQTT\_DEMO
#include <stdio.h>
#include <string.h>
#include "stm32f1xx\_hal.h"
#include "mqtt\_client\_demo.h"
#include "w5500.h"
#include "socket.h"
#include "MQTT/MQTTClient.h"

#define MQTT\_CLIENT\_BUFFER\_SIZE 1024
#define MQTT\_SOCKET 0
#define MQTT\_TIMEOUT 1000

static Network network; 
static MQTTClient client;

static uint8\_t tx_buffer[MQTT_CLIENT_BUFFER_SIZE]; // 发送缓存
static uint8\_t rx_buffer[MQTT_CLIENT_BUFFER_SIZE]; // 接收缓存
static uint8\_t message_buffer[MQTT_CLIENT_BUFFER_SIZE]; //消息缓存 

static uint8\_t server_ip[4] = { 192, 168, 2, 78 }; // MQTT服务器IP
static uint16\_t server_port = 1883; // MQTT服务器端口


// MQTT消息接收回调函数。
void on\_mqtt\_message(MessageData \*md) {
	memset(message_buffer, 0, MQTT_CLIENT_BUFFER_SIZE);
	MQTTMessage \*msg = md->message;
	printf("message received len = %d.\r\n", msg->payloadlen);
	memcpy(message_buffer, (uint8\_t\*) msg->payload, msg->payloadlen);
	printf("message:%s\r\n", message_buffer);
}

void mqtt\_client\_init(void) {
	int ret;
	// 初始化Network
	NewNetwork(&network, MQTT_SOCKET);

	// 连接MQTT服务器
	ConnectNetwork(&network, server_ip, server_port);
	MQTTClientInit(&client, &network, MQTT_TIMEOUT, tx_buffer,
	MQTT_CLIENT_BUFFER_SIZE, rx_buffer, MQTT_CLIENT_BUFFER_SIZE);

	MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
	data.willFlag = 0;
	data.MQTTVersion = 3;
	data.clientID.cstring = "stm32\_w5500";
	data.username.cstring = "";
	data.password.cstring = "";

	data.keepAliveInterval = 60;
	data.cleansession = 1;

	// 建立MQTT连接
	ret = MQTTConnect(&client, &data);
	if (ret != SUCCESSS) {
		printf("mqtt\_client\_init:mqtt connect failed(%d)\r\n", ret);
		while (1)
			;
	}
	printf("mqtt\_client\_init:connected\r\n");

	// 订阅主题
	ret = MQTTSubscribe(&client, "stm32\_iot/led\_ctr", QOS0, on_mqtt_message);
}

void mqtt\_client\_loop(void) {
	MQTTMessage msg;
	msg.qos = QOS0;
	msg.retained = 0;
	msg.dup = 0;
	msg.payload = "{\"led\":\"0\",\"state\":\"on\"}";
	msg.payloadlen = strlen((const char\*)msg.payload);
	while (client.isconnected) {
		MQTTPublish(&client, "stm32\_iot/led\_state", &msg);
		HAL\_Delay(2000);
		MQTTYield(&client, 60);
	}
}
#endif

2、主程序

在main.c文件中添加如下代码

/\* Private includes ----------------------------------------------------------\*/
/\* USER CODE BEGIN Includes \*/
#include <stdio.h>
#include "w5500\_port.h"
#include <string.h> // memcmp
#include "app\_config.h"
#ifdef MQTT\_DEMO
#include "mqtt\_client\_demo.h"
#endif
/\* USER CODE END Includes \*/

int main(void) {
	/\* USER CODE BEGIN 1 \*/

	/\* USER CODE END 1 \*/

	/\* MCU Configuration--------------------------------------------------------\*/

	/\* Reset of all peripherals, Initializes the Flash interface and the Systick. \*/
	HAL\_Init();

	/\* USER CODE BEGIN Init \*/

	/\* USER CODE END Init \*/

	/\* Configure the system clock \*/
	SystemClock\_Config();

	/\* USER CODE BEGIN SysInit \*/

	/\* USER CODE END SysInit \*/

	/\* Initialize all configured peripherals \*/
	MX\_GPIO\_Init();
	MX\_USART1\_UART\_Init();
	MX\_SPI1\_Init();
	/\* USER CODE BEGIN 2 \*/
	printf("-----STM32 W5500 Ethernet Demo-----\r\n");
	w5500\_restart();  // hardware restart through RESET pin
	wiznet\_register();
	w5500\_network\_init\_static();
	wiznet\_chip\_config();


#ifdef MQTT\_DEMO
	mqtt\_client\_init();
	mqtt\_client\_loop();
#endif

	/\* USER CODE END 2 \*/

	/\* Infinite loop \*/
	/\* USER CODE BEGIN WHILE \*/
	while (1) {
		/\* USER CODE END WHILE \*/
		//loopback\_tcpc(0, (uint8\_t\*) recv\_buff, destip, destport);
		/\* USER CODE BEGIN 3 \*/
	}
	/\* USER CODE END 3 \*/
}