linux 下利用MQTT进行数据传递

一，安装MQTT服务

1. 安装MQTT服务器
   sudo apt-get install mosquitto

2. 安装MQTT客户端
   sudo apt-get install mosquitto-clients

3. 配置MQTT服务器
   sudo nano /etc/mosquitto/mosquitto.conf

    allow_anonymous true
    listener 1883 

4. 重启服务
   sudo service mosquitto restart

二，封装一下

#pragma once
#include <MQTTAsync.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <thread>
#include <memory>
#include <Util/logger.h>

using namespace toolkit;

#define SEERVERIP "127.0.0.1"
#define ClientID "server"
bool isConnected{false};

int onMessrecv(void *context, char *topicName, int topicLen, MQTTAsync_message *message)
{
    // printf("recv name:\ntopic:%s,payload:%s\n", topicName, (char *)message->payload);
    // MQTTAsync_free(topicName);
    // MQTTAsync_free(message);
    return 1;
}
void onSubscribe(void *context, MQTTAsync_successData *response)
{
    std::cout<<"sub success!"<<std::endl;
}

void onConnect(void *context, MQTTAsync_successData *response)
{
    InfoL<<"连接MQTT 服务器成功!";
    // MQTTAsync client = (MQTTAsync)context;
    // int ret;
    // MQTTAsync_responseOptions response_opt = MQTTAsync_responseOptions_initializer;
    // response_opt.onSuccess = onSubscribe;
    // // 订阅/pub主题消息
    // ret = MQTTAsync_subscribe(client, "/pub", 1, &response_opt); 
    // if (ret != MQTTASYNC_SUCCESS)
    // {
    //     printf("fail to sub!\n");
    // }
    isConnected = true;
}

void disConnect(void *context, MQTTAsync_failureData *response)
{
    ErrorL<<"连接MQTT 服务器失败!";
}

class MQTTClicent : public std::enable_shared_from_this<MQTTClicent>
{
public:
    using Ptr = std::shared_ptr<MQTTClicent>;

    MQTTClicent()
    {
        int ret;
        MQTTAsync_connectOptions conn_opt = MQTTAsync_connectOptions_initializer; // 初始化连接选项
        ret = MQTTAsync_create(&client, SEERVERIP, ClientID, MQTTCLIENT_PERSISTENCE_NONE, NULL);
        if (ret != MQTTASYNC_SUCCESS)
        {
            ErrorL<<"创建MQTT 客户端失败";
            return;
        }
        // 初始化接收消息回调
        ret = MQTTAsync_setCallbacks(client, NULL, NULL, onMessrecv, NULL);
        if (ret != MQTTASYNC_SUCCESS)
        {
            ErrorL<<"设置接受消息回调 失败";
            return;
        }

        conn_opt.onSuccess = onConnect;
        conn_opt.onFailure = disConnect;
        conn_opt.automaticReconnect = 1;
        conn_opt.context = client;
        conn_opt.cleansession = 0;
        ret = MQTTAsync_connect(client, &conn_opt);
        if (ret != MQTTASYNC_SUCCESS)
        {
            ErrorL<<"连接MQTT 服务器失败！";
            return;
        }
    }

    int sendMessage(const char *destinationName, const MQTTAsync_message *msg, MQTTAsync_responseOptions *response)
    {
        if (isConnected)
        {
            int ret = MQTTAsync_sendMessage(client, destinationName, msg, response);
            if (ret != MQTTASYNC_SUCCESS)
            {
                ErrorL<<"发布数据失败！";
            }
            return ret;
        }
    }

private:
    MQTTAsync client;
};

三，使用

将数据封装成消息，然后定义一个唯一的主题 发布即可

    void pushData()
    {
        MQTTAsync_message message = MQTTAsync_message_initializer;
        MQTTAsync_responseOptions res_option = MQTTAsync_responseOptions_initializer;

        // 封装消息
        char buffer[128];
        sprintf(buffer, " %d,%d ", temperature, humidity);
        message.payload = buffer;
        message.payloadlen = strlen(buffer);
        message.qos = 1;
       //发布信息  TOPIC_IN_TEMPERATURE_HUMIDITY 为此消息的主题
        mqtt->sendMessage(TOPIC_IN_TEMPERATURE_HUMIDITY, &message, &res_option);
    }