VC MFC C++ MQTT VC编译MQTT VC调用MQTT dll eclipse-paho-mqtt

JS HTML Web端使用MQTT通讯测试

系统：Windows10 64位

开发环境：Visual Studio 2013 64位

MQTT源码库：eclipse-paho-mqtt-c-src-1.2.0

测试工具：MQTTBox

MQTT服务器：阿里云部署EMQX

VC MFC程序运行图示：

一、编译MQTT 生成dll lib

1、下载MQTT源码库：eclipse-paho-mqtt-c-src

      下载github地址：https://github.com/eclipse

2、解压、使用Visual Studio编译出动态链接库

      解压eclipse-paho-mqtt-c-src

3、使用Visual Studio编译dll/lib

打开目录eclipse-paho-mqtt-c-src-1.2.0Windows Build中的Paho C MQTT APIs.sln工程

使用VS菜单->生成->生成解决方案，来生成dll和lib，生成目录为eclipse-paho-mqtt-c-src-1.2.0Windows BuildDebug

错误和失败的是带SSL的，需要电脑安装OPENSSL库才能编译，需要SSL需求的同学自己安装OPENSSL再编译

paho-mqtt3a ： 一般实际开发中就是使用这个，a表示的是异步消息推送（asynchronous）。

paho-mqtt3as ： as表示的是 异步+加密（asynchronous+OpenSSL）。

paho-mqtt3c ： c 表示的应该是同步（Synchronize），一般性能较差，是发送+等待模式。

paho-mqtt3cs ： 同上，增加了一个OpenSSL而已

带S的都需要OpenSSL才能编译，test工程也一样

我的电脑没安装OpenSSL，所以只生成了

paho-mqtt3a.dll 

paho-mqtt3a.lib

paho-mqtt3c.dll

paho-mqtt3c.lib

一般使用足够了，保存关闭工程，以后编译还会用到。

二、调用dll lib编写VC MQTT客户端

1、新建MFC工程

选择MFC用户程序，向导中选择基于对话框，在共享dll中使用MFC

2、设置链接和头文件

将eclipse-paho-mqtt-c-src-1.2.0src目录中所有文件复制到此工程目录中include目录中（新建）

在工程中创建一个MQTT筛选器，添加MQTTAsync.h和MQTTClient.h

将刚才生成的dll复制到工程目录Debug，将刚才生成的lib复制到工程目录工程源码目录中

在工程属性页添加lib链接库

3、设计界面

4、编写代码，以下只列出MQTT调用核心代码，界面控件的响应和控制就不列出了，只实现基础功能，后期再添加新功能

包含头文件

连接服务器代码

  MQTT_Conn_opts = MQTTClient_connectOptions_initializer;  MQTT_Pubmsg = MQTTClient_message_initializer;    int rc;  MQTTClient_create(&MQTT_Client, ServerAddStr, CLIENTID, MQTTCLIENT_PERSISTENCE_NONE, NULL);  MQTT_Conn_opts.keepAliveInterval = atoi(KeepAliveStr);  MQTT_Conn_opts.cleansession = 1;  MQTT_Conn_opts.username = UserName;  MQTT_Conn_opts.password = PassWord;   MQTTClient_setCallbacks(MQTT_Client, NULL, MQTT_ConnLost, MQTT_MsgArrvd, MQTT_Delivered);   if ((rc = MQTTClient_connect(MQTT_Client, &MQTT_Conn_opts)) != MQTTCLIENT_SUCCESS){   AfxMessageBox("Failed to connect");// , return code %dn", rc);   return;  }  else{   printf("MQTT Server Connect OK  n");   ((CButton*)GetDlgItem(IDC_BUTTON_ConnectServer))->SetWindowText("断开连接");//填入文本框   GetDlgItem(IDC_BUTTON_SendMsg)->EnableWindow(TRUE);// 发布按钮有效  }

断开连接代码

 // 断开连接 void CMQTT_TestDlg::DisconnectConnect() {  MQTTClient_disconnect(MQTT_Client, 10000);  MQTTClient_destroy(&MQTT_Client);  ((CButton*)GetDlgItem(IDC_BUTTON_ConnectServer))->SetWindowText("连接服务器");//填入文本框 }

发送消息代码

 // 发布消息按钮 void CMQTT_TestDlg::OnBnClickedButtonSendmsg() {  int rc;  CString PublishStr, SendMsgStr;  ((CEdit*)GetDlgItem(IDC_EDIT_Publish))->GetWindowText(PublishStr);//获取文本框内容  ((CEdit*)GetDlgItem(IDC_EDIT_SendMsg))->GetWindowText(SendMsgStr);//获取文本框内容  char buff[2048];  memset(buff, 0, sizeof(buff));  strcpy_s(buff, sizeof(buff),SendMsgStr );  MQTT_Pubmsg.payload = buff;  MQTT_Pubmsg.payloadlen = strlen(buff);  MQTT_Pubmsg.qos = QOS;  MQTT_Pubmsg.retained = 0;  MQTTClient_publishMessage(MQTT_Client, PublishStr, &MQTT_Pubmsg, &MQTT_Token);  printf("Waiting for up to %d seconds for publication of %sn"   "on topic %s for client with ClientID: %sn",   (int)(TIMEOUT / 1000), SendMsgStr, PublishStr, CLIENTID);  rc = MQTTClient_waitForCompletion(MQTT_Client, MQTT_Token, TIMEOUT);  printf("Message with delivery token %d deliveredn", MQTT_Token);  while (deliveredtoken != MQTT_Token); }

订阅按钮代码

 // 订阅按钮 void CMQTT_TestDlg::OnBnClickedButtonSubscribe() {  /* 订阅多条  char *const topics[] = { (char*)"topics1","topics2" };  //rc = MQTTClient_unsubscribeMany(client, 2, topics);  */  CString SubscribeStr;  ((CEdit*)GetDlgItem(IDC_EDIT_SubscribeMsg))->GetWindowText(SubscribeStr);//获取文本框内容  if (SubscribeStr.GetLength() <= 0){   AfxMessageBox("请输入要订阅的消息");  }else{   if (MQTTClient_subscribe(MQTT_Client, SubscribeStr, QOS) == MQTTCLIENT_SUCCESS){    int n = m_SubscribeList.GetItemCount();//获取list里面有多少行    m_SubscribeList.InsertItem(n, SubscribeStr);//插入行    ((CEdit*)GetDlgItem(IDC_EDIT_SubscribeMsg))->SetWindowText("");//填入文本框   }else{    AfxMessageBox("订阅失败");   }  } }

取消订阅代码

 // 取消订阅按钮 void CMQTT_TestDlg::OnBnClickedButtonUnsubscribe() {  //获取选中的行  int r = m_SubscribeList.GetSelectionMark();  if (m_SubscribeList.GetSelectedCount() != 0){   CString str = m_SubscribeList.GetItemText(r, 0);      printf("取消订阅  第 %d 行  内容：%srn", r,str);   if (MQTTClient_unsubscribe(MQTT_Client, str) == MQTTCLIENT_SUCCESS){    m_SubscribeList.DeleteItem(r);   }else{    AfxMessageBox("取消订阅失败");   }  }else{   AfxMessageBox("请在列表中选择要取消订阅的消息");  } }

消息已送达回调

 void MQTT_Delivered(void *context, MQTTClient_deliveryToken dt) {  printf("Message with token value %d delivery confirmedn", dt);  deliveredtoken = dt; }

消息到达回调

 int MQTT_MsgArrvd(void *context, char *topicName, int topicLen, MQTTClient_message *message) {  CString RevMsg,LastRevMsg,TopicName,Msg;  int i;  char* payloadptr;  char buf[4096];  memset(buf, 0, sizeof(buf));  printf("Message arrivedn");  printf("     topic: %sn", topicName);  printf("   message: ");  payloadptr = (char *)message->payload;  for (i = 0; i<message->payloadlen; i++){   buf[i] = *payloadptr++;   //putchar(*payloadptr++);  }  putchar('n');  //memcpy(buf, payloadptr, message->payloadlen);  TopicName.Format("%s", topicName);  Msg.Format("%s", buf);  RevMsg = "rn收到 " + TopicName + " 的消息：" + Msg;  printf("dddddddddddd  %srn", RevMsg);  CMQTT_TestDlg *pDlg = (CMQTT_TestDlg*)g_pDlg;  pDlg->AddMsgToMsgBox(RevMsg);   MQTTClient_freeMessage(&message);  MQTTClient_free(topicName);  return 1; }

服务器连接断开回调

 void MQTT_ConnLost(void *context, char *cause) {  printf("nConnection lostn");  printf("     cause: %sn", cause); }