实现树莓派与上位机进行mqtt转tcp通信

clown955

已于 2024-07-11 15:41:21 修改

阅读量1.8k

点赞数 38

分类专栏： MQTT 文章标签： tcp/ip 单片机 stm32

于 2024-05-24 14:11:37 首次发布

本文链接：https://blog.youkuaiyun.com/qq_61616201/article/details/139173429

版权

MQTT 专栏收录该内容

3 篇文章

订阅专栏

本文详细介绍了如何在树莓派上通过paho库建立MQTT客户端，并编写mqtt转tcp的网关程序，连接到Linux系统。同时，利用Windows下的网络调试助手模拟TCP上位机，进行通信测试，确保数据在MQTT与TCP之间顺利转换。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

1.连接树莓派

2.在树莓派安装paho的库

3.在树莓派编写mqtt客户端代码

4.在linux下编写mqtt转tcp的网关程序

5.用windows下的网络调试助手模拟只能接收TCP消息的上位机

6.通信测试

1.连接树莓派

配置新的树莓派请参考

刚拿到树莓派，该怎么使用（折腾）呢？_树莓派拿到后做什么-优快云博客

本人连接树莓派用的NVC可以显示图形化界面，下载VNC

链接: https://pan.baidu.com/s/1IILrcjdCIErBwDWdcv3lPg?pwd=tb63 提取码: tb63

跟着指导一步一步next即可

安装好后点击File--》new connect

（若遇到登录，点击取消即可）

点击它，输入账号密码

连接成功后即可操作树莓派可视化界面

2.在树莓派安装paho的库

因为mqtt需要用paho的库，所以要安装库

在windows下下载该文件并解压

链接: https://pan.baidu.com/s/1sTmDhjWqQrSN2A3DdgOtnw?pwd=z123 提取码: z123

因为windows不可以直接拖动文件到树莓派中，要下载WINscp软件

链接: https://pan.baidu.com/s/1EEkpGfmXh24MYEAp5flHwg?pwd=xegm 提取码: xegm

按步骤安装后，连接树莓派

连接成功后可以将解压的paho.mqtt.c-1.3.0文件复制或直接拖到树莓派桌面上

在桌面创建mqtt文件夹

在该文件夹里创建文件mqtt.c以及makefile文件

将复制过来的paho.mqtt.c-1.3.0文件放到mqtt文件夹中

进入到该文件里，右击打开终端

输入以下命令并回车进行编译

make

编译paho.mqtt.c-1.3.0若提示 openssl 错误解决方法

树莓派（Raspberry Pi）安装使用 Eclipse paho C库_树莓派安装 matt paho c-优快云博客

之后进行安装

sudo make uninstall（去掉前面有错的安装，之前未安装可不加)

sudo make install（重新安装）

3.在树莓派编写mqtt客户端代码

mqtt.c中代码如下

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <unistd.h>
//以下为库头文件的引入注意路径别写错
#include "./paho.mqtt.c-1.3.0/paho.mqtt.c-1.3.0/src/MQTTClient.h"

#define ALIYUN_MQTT_HOST      "tcp://xxx.xxx.xxx.xxx:1883"//你的mqtt代理服务器的ip
#define ALIYUN_MQTT_CLIENT_ID ""
#define ALIYUN_MQTT_USERNAME  ""
#define ALIYUN_MQTT_PASSWORD  ""
#define TOPIC_S               "up"//订阅话题
#define TOPIC_P               "down"//发布话题

#define QOS         1
char buf[1024]={0};

void connection_lost(void *context, char *cause) {
    printf("\nConnection lost\n");
    printf("     cause: %s\n", cause);
}
 
int messageArrived(void *context, char *topicName, int topicLen, MQTTClient_message *message) {
    printf("Message arrived\n");
    strcpy(buf,message->payload);
    printf("%s\n",buf);
    return 1;
}


int main(int argc, char *argv[]) {
    MQTTClient client;
    MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
    MQTTClient_message pubmsg = MQTTClient_message_initializer;
    MQTTClient_deliveryToken token;
    int rc;
 
    MQTTClient_create(&client, ALIYUN_MQTT_HOST, ALIYUN_MQTT_CLIENT_ID,
        MQTTCLIENT_PERSISTENCE_NONE, NULL);
 
    MQTTClient_setCallbacks(client, NULL, connection_lost, messageArrived, NULL);
 
    conn_opts.keepAliveInterval = 20;
    conn_opts.cleansession = 1;
    conn_opts.username = ALIYUN_MQTT_USERNAME;
    conn_opts.password = ALIYUN_MQTT_PASSWORD;
 
    if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) {
        printf("Failed to connect, return code %d\n", rc);
        exit(EXIT_FAILURE);
    }
    MQTTClient_subscribe(client, TOPIC_S, QOS);

    while (1)
    {
        scanf("%s",buf);
        pubmsg.payload = buf;
        pubmsg.payloadlen = strlen((char *)pubmsg.payload);
        pubmsg.qos = QOS;
        pubmsg.retained = 0;
        MQTTClient_publishMessage(client, TOPIC_P, &pubmsg, &token);
        MQTTClient_waitForCompletion(client, token, 10000L);
        printf("Message sent\n"); 
    }
    MQTTClient_unsubscribe(client, TOPIC_S);
    MQTTClient_disconnect(client, 10000);
    MQTTClient_destroy(&client);

    return rc;
}

makefile文件代码

#指定生成的文件名
OJB_OUT = mqtt.out

#指定每一个c文件对应的.o文件
OBJS =mqtt.o

#指定编译器
CC = gcc

#指定需要的库
ULDFLAGS = -l m -l paho-mqtt3c

###########################################
#以下的内容不需要修改
###########################################
all:$(OJB_OUT)

$(OJB_OUT):$(OBJS)
	$(CC) -o $@ $^ $(ULDFLAGS)

dep_files := $(foreach f,$(OBJS),.$(f).d)
dep_files := $(wildcard $(dep_files))

ifneq ($(dep_files),)
  include $(dep_files)
endif

%.o:%.c
	$(CC) -Wp,-MD,.$@.d -c $< -o $@
    
clean:
	rm -rf .*.o.d *.o $(OJB_OUT)

之后右击mqtt文件在终端打开

输入以下命令并回车进行编译

make

之后会生成这几个文件，其中的mqtt.out即为生成的可执行文件

然后运行可执行文件即可启动mqtt客户端

./mqtt.out

4.在linux下编写mqtt转tcp的网关程序

mqtt_change.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include<pthread.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <unistd.h>
#include "MQTTClient.h"
 
//阿里云
#define ALIYUN_MQTT_HOST      "tcp://xxx.xxx.xxx.xxx:1883"//你的mqtt代理服务器的ip
#define ALIYUN_MQTT_CLIENT_ID ""//设备id
#define ALIYUN_MQTT_USERNAME  ""//用户名
#define ALIYUN_MQTT_PASSWORD  ""//密码
#define TOPIC_S               "down"
#define TOPIC_P               "up"

#define QOS         1
char buf[1024]={0};//数据包
int flagA = 0;//标志位：MQTT收到消息为1,TCP发送后为0
int flagB = 0;//标志位：TCP收到消息为1,MQTT发送后为0
int flagC = 0;//标志位：客户端连接为0,退出为1
int acceptfd;
void connection_lost(void *context, char *cause) {
    printf("\nConnection lost\n");
    printf("     cause: %s\n", cause);
}
 
int messageArrived(void *context, char *topicName, int topicLen, MQTTClient_message *message) {
    printf("Message arrived\n");
    strcpy(buf,message->payload);
    flagA = 1;
    return 1;
}
//线程函数--》处理tcp的发
void * fun_tcp_send(void *arg)
{
    while (1)
    {
        if(flagA == 1)
        {
            send(acceptfd, buf, strlen(buf), 0);
            flagA = 0;
            printf("tcp send is ok\n");
        }
        if(flagC == 1)
        {
            break;
        }
    }
     
}
//线程函数--》处理tcp的收发
void * fun_tcp(void *arg)
{
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0)
    {
        perror("socket err");
        //return;
    }
    struct sockaddr_in saddr;
    saddr.sin_family = AF_INET;
    saddr.sin_port = htons(8887);
    saddr.sin_addr.s_addr = inet_addr("0.0.0.0");
    socklen_t len = sizeof(saddr);
    if (bind(sockfd, (struct sockaddr *)&saddr, len))
    {
        perror("bind err");
        //return;
    }
    if (listen(sockfd, 6) < 0)
    {
        perror("listen err");
        //return;
    }
    printf("listen success\n");
    struct sockaddr_in aaddr;
    while (1)
    {
        acceptfd = accept(sockfd, (struct sockaddr *)&aaddr, &len);
        if (acceptfd < 0)
        {
            perror("accept err");
            //return -1;
        }
        flagC = 0;
        printf("accept success\n");
        //来电显示:打印客户端的ip和port
        printf("ip:%s port:%d\n",inet_ntoa(aaddr.sin_addr),ntohs(aaddr.sin_port));
        
        //创建线程，发tcp的消息
        pthread_t tid2;
        if(pthread_create(&tid2,NULL,fun_tcp_send,NULL))
        {
            perror("create err");
            //return;
        }
        //收消息
        while (1)
        {
            //接收数据
            ssize_t ret = recv(acceptfd, buf, sizeof(buf), 0);
            if (ret < 0)
            {
                perror("recv err");
                //return;
            }
            else if (ret == 0)
            {
                printf("client exit\n");
                flagC = 1;
                close(acceptfd);
                break;
            }
            else
            {
                flagB = 1;//tcp收到消息
                printf("%s\n",buf);
                printf("%d\n",buf[0]);
                printf("tcp recv is ok\n");
            }
        }
        pthread_join(tid2,NULL);
    }
    close(sockfd);
}

int main(int argc, char *argv[]) {
    //创建线程，收发tcp的消息
    pthread_t tid;
	if(pthread_create(&tid,NULL,fun_tcp,NULL))
	{
		perror("create err");
		return -1;
	}

    //mqtt
    MQTTClient client;
    MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
    MQTTClient_message pubmsg = MQTTClient_message_initializer;
    MQTTClient_deliveryToken token;//分发标记
    int rc;
 
    MQTTClient_create(&client, ALIYUN_MQTT_HOST, ALIYUN_MQTT_CLIENT_ID,
        MQTTCLIENT_PERSISTENCE_NONE, NULL);
 
    MQTTClient_setCallbacks(client, NULL, connection_lost, messageArrived, NULL);
 
    conn_opts.keepAliveInterval = 20;
    conn_opts.cleansession = 1;
    conn_opts.username = ALIYUN_MQTT_USERNAME;
    conn_opts.password = ALIYUN_MQTT_PASSWORD;
 
    if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) {
        printf("Failed to connect, return code %d\n", rc);
        exit(EXIT_FAILURE);
    }
     //订阅主题
    MQTTClient_subscribe(client, TOPIC_S, QOS);

    while (1)
    {
        if(flagB == 1)
        {
            pubmsg.payload = buf;
            pubmsg.payloadlen = strlen((char *)pubmsg.payload);
            pubmsg.qos = QOS;
            pubmsg.retained = 0;
            //发布主题
            MQTTClient_publishMessage(client, TOPIC_P, &pubmsg, &token);

            MQTTClient_waitForCompletion(client, token, 10000L);
            printf("Message sent\n"); 
            flagB = 0;
        }  
    }
    MQTTClient_unsubscribe(client, TOPIC_S);
    MQTTClient_disconnect(client, 10000);
    MQTTClient_destroy(&client);
    pthread_join(tid,NULL);
    return rc;
}

makefile

#指定生成的文件名
OJB_OUT = mqtt_change.out

#指定每一个c文件对应的.o文件
OBJS = cJSON.o mqtt_change.o

#指定编译器
CC = gcc

#指定需要的库
ULDFLAGS = -l m -l paho-mqtt3c -pthread

###########################################
#以下的内容不需要修改
###########################################
all:$(OJB_OUT)

$(OJB_OUT):$(OBJS)
	$(CC) -o $@ $^ $(ULDFLAGS)

dep_files := $(foreach f,$(OBJS),.$(f).d)
dep_files := $(wildcard $(dep_files))

ifneq ($(dep_files),)
  include $(dep_files)
endif

%.o:%.c
	$(CC) -Wp,-MD,.$@.d -c $< -o $@
    
clean:
	rm -rf .*.o.d *.o $(OJB_OUT)