初出茅庐的小李博客之使用立创开发板(ESP32)连接到EMQX Platform【MQTT TLS/SSL 端口连接】

介绍

手上有一块立创开发板，本着不吃灰的原则把它用起来，今天就来用它来连接上自己部署的MQTT服务器进行数据通信。

硬件：立创开发板
开发环境：Arduino IDE Win11
MQTT 平台：EMQX Platform

立创开发板介绍：

初出茅庐的小李博客之立创开发板初体验【Arduino IDE开发环境】：
地址：https://blog.csdn.net/weixin_43176183/article/details/139101412?spm=1001.2014.3001.5501

MQTT.fx客户端接入EMQX Platform

初出茅庐的小李博客之MQTT.fx客户端接入EMQX Platform
地址：https://blog.csdn.net/weixin_43176183/article/details/139190727?spm=1001.2014.3001.5501

参考文档：
https://docs.emqx.com/zh/cloud/latest/connect_to_deployments/esp32.html

过程记录：

安装MQTT依赖库

在 Arduino IDE 中完成以下安装。
先安装 ESP32 开发板。
点击工具 -> 开发板 -> 开发板管理。搜索 ESP32，点击安装 我已经安装过。
安装 PubSub client 库。
点击项目 -> 加载库 -> 管理库…。搜索 PubSubClient，安装 PubSubClient by Nick O’Leary。
通过 TCP 端口连接

写代码

• 引入对应的库

#include "WiFi.h"
#include <PubSubClient.h>
#include <WiFiClientSecure.h>

• 定义用户自定义参数

// WiFi Credentials
const char *ssid     = "AQST";             // Replace with your WiFi name
const char *password = "12345678";         // Replace with your WiFi password// MQTT Broker Settings
const char *mqtt_broker   = "xxxxxx.ala.cn-hangzhou.emqxsl.cn";//这里定义自己的连接地址
const char *mqtt_topic    = "emqx/esp32";
const char *mqtt_username = "AQ";
const char *mqtt_password = "123456";
const int   mqtt_port     = 8883;

• 编写连接代码【准确的来说叫改写】

/连接Wifi热点函数
void ConnectToWiFi(void) 
{WiFi.begin(ssid, password);Serial.print("Connecting to WiFi");while (WiFi.status() != WL_CONNECTED){delay(500);Serial.print(".");}Serial.println("\nConnected to WiFi");
}
//连接MQTT代理函数
void ConnectToMQTT(void) 
{while (!mqtt_client.connected()){String client_id = "esp32-client-" + String(WiFi.macAddress());Serial.printf("Connecting to MQTT Broker as %s...\n", client_id.c_str());if(mqtt_client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {Serial.println("Connected to MQTT broker");mqtt_client.subscribe(mqtt_topic);mqtt_client.publish(mqtt_topic, "Hi EMQX I'm ESP32 by Arduino IED ^^");  // Publish message upon connection}else {Serial.print("Failed to connect to MQTT broker, rc=");Serial.print(mqtt_client.state());Serial.println(" Retrying in 5 seconds.");delay(5000);}}
}
//MQTT 回调函数
void MqttCallback(char *topic, byte *payload, unsigned int length)
{Serial.print("Message received on topic: ");Serial.println(topic);Serial.print("Message: ");for (unsigned int i = 0; i < length; i++) {Serial.print((char) payload[i]);//打印有效载荷的信息}Serial.println("\n-----------------------");
}

• 函数调用

void setup(void)
{Serial.begin(115200);                         //设置串口参数ConnectToWiFi();                              //连接Wifi热点// Set Root CA certificateespClient.setCACert(ca_cert);                 //设置CA证书mqtt_client.setServer(mqtt_broker, mqtt_port);//指定代理 指定端口mqtt_client.setKeepAlive(60);                 //保活时间mqtt_client.setCallback(MqttCallback);        //回调函数ConnectToMQTT();                              //连接MQTT 代理}void loop(void) 
{if (!mqtt_client.connected()) {ConnectToMQTT();}mqtt_client.loop();
}

特别提示：这里的地址要写自己的地址 CA证书也要用自己的证书 否则连不上

官方原话：
添加服务端证书。如果您在使用公共 MQTT Broker、Serverless 部署或基础版部署的 TLS/SSL 端口连接，在此下载 CA 证书。 如您使用专业版 / BYOC 部署的 TLS/SSL 端口连接，请使用自己的服务端证书。

• 开启MQTT服务器
  

• 编译烧录代码

用MQTT.fx连接到MQTT服务器跟ESP32开发板进行通信

发布消息：

ESP32收到订阅消息

这里可以看到开发板收到了消息 但是客户端提示收到的消息不是标准json

改进一下发送的数据格式

{"mag": "This is Json Data"
}

总结：

利用Arduino IED 进行MQTT通信 确实很方便，很容易就能实现两个设备的交互、但是使用库的缺点也很明显 有很多api不太懂它的意思，还需要进一步研究。

完整代码

#include "WiFi.h"
#include <PubSubClient.h>
#include <WiFiClientSecure.h>// WiFi Credentials
const char *ssid     = "AQST";             // Replace with your WiFi name
const char *password = "12345678";         // Replace with your WiFi password// MQTT Broker Settings
const char *mqtt_broker   = "xxxxxxx.ala.cn-hangzhou.emqxsl.cn";//这里要改成自己的地址！！！！
const char *mqtt_topic    = "emqx/esp32";
const char *mqtt_username = "AQ";
const char *mqtt_password = "123456";
const int   mqtt_port     = 8883;WiFiClientSecure espClient;
PubSubClient mqtt_client(espClient);void ConnectToWiFi(void);//函数声明
void ConnectToMQTT(void);//函数声明
void MqttCallback(char *mqtt_topic, byte *payload, unsigned int length);//函数声明const char *ca_cert = R"EOF(
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
)EOF";void setup(void)
{Serial.begin(115200);                         //设置串口参数ConnectToWiFi();                              //连接Wifi热点// Set Root CA certificateespClient.setCACert(ca_cert);                 //设置CA证书mqtt_client.setServer(mqtt_broker, mqtt_port);//指定代理 指定端口mqtt_client.setKeepAlive(60);                 //保活时间mqtt_client.setCallback(MqttCallback);        //回调函数ConnectToMQTT();                              //连接MQTT 代理}//连接Wifi热点函数
void ConnectToWiFi(void) 
{WiFi.begin(ssid, password);Serial.print("Connecting to WiFi");while (WiFi.status() != WL_CONNECTED){delay(500);Serial.print(".");}Serial.println("\nConnected to WiFi");
}
//连接MQTT代理函数
void ConnectToMQTT(void) 
{while (!mqtt_client.connected()){String client_id = "esp32-client-" + String(WiFi.macAddress());Serial.printf("Connecting to MQTT Broker as %s...\n", client_id.c_str());if(mqtt_client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {Serial.println("Connected to MQTT broker");mqtt_client.subscribe(mqtt_topic);mqtt_client.publish(mqtt_topic, "Hi EMQX I'm ESP32 by Arduino IED ^^");  // Publish message upon connection}else {Serial.print("Failed to connect to MQTT broker, rc=");Serial.print(mqtt_client.state());Serial.println(" Retrying in 5 seconds.");delay(5000);}}
}
//MQTT 回调函数
void MqttCallback(char *topic, byte *payload, unsigned int length)
{Serial.print("Message received on topic: ");Serial.println(topic);Serial.print("Message: ");for (unsigned int i = 0; i < length; i++) {Serial.print((char) payload[i]);//打印有效载荷的信息}Serial.println("\n-----------------------");
}void loop(void) 
{if (!mqtt_client.connected()) {ConnectToMQTT();}mqtt_client.loop();
}// WiFiClient espClient;
// PubSubClient mqtt_client(espClient);// void setup(void) 
// {
//   Serial.begin(115200);
//   ConnectToWiFi(); //连接指定热点
//   //mqtt_client.setServer(mqtt_broker, mqtt_port);
//   espClient.setCACert(ca_cert);
//   mqtt_client.setKeepAlive(60);
//   mqtt_client.setCallback(MqttCallback); // Corrected callback function name
//   ConnectToMQTT();
// }// void loop(void) 
// {
//   if (!mqtt_client.connected()) 
//   {
//     ConnectToMQTT();
//   }
//   mqtt_client.loop();
// }//用户自定义函数
// void ConnectToWiFi(void) 
// {
//     WiFi.begin(ssid, password);
//     Serial.print("Connecting to WiFi");
//     while (WiFi.status() != WL_CONNECTED) 
//     {
//         delay(500);
//         Serial.print(".");
//     }
//     Serial.println("\nConnected to WiFi");
// }
// //用户自定义函数
// void ConnectToMQTT(void) 
// {
//   while (!mqtt_client.connected()) 
//   {
//     String client_id = "esp32-client-" + String(WiFi.macAddress());//     Serial.printf("Connecting to MQTT Broker as %s.....\n", client_id.c_str());//     if (mqtt_client.connect(client_id.c_str(), mqtt_username, mqtt_password))
//     {
//       Serial.println("Connected to MQTT broker");
//       mqtt_client.subscribe(mqtt_topic);
//       mqtt_client.publish(mqtt_topic, "Hi EMQX I'm ESP32 ^^"); // Publish message upon successful connection
//     }
//     else 
//     {
//       Serial.print("Failed, rc=");
//       Serial.print(mqtt_client.state());
//       Serial.println(" try again in 5 seconds");
//       delay(5000);
//     }
//   }
// }//用户自定义回调函数
// void MqttCallback(char *mqtt_topic, byte *payload, unsigned int length)
// {
//   Serial.print("Message received on mqtt_topic: ");
//   Serial.println(mqtt_topic);
//   Serial.print("Message: ");
//   for (unsigned int i = 0; i < length; i++) 
//   {
//     Serial.print((char) payload[i]);
//   }
//   Serial.println("\n-----------------------");
// }

视频：

https://www.bilibili.com/video/BV1gJ4m1A7bg/?pop_share=1