1 #include <stdio.h>
  2 #include <stdlib.h>
  3 #include <string.h>
  4 #include <unistd.h>
  5 #include "MQTTClient.h"
  6 
  7 #define MQTT_Uri    "tcp://39.96.35.207:1883"   // MQTT服务器的地址和端口号
  8 #define ClientId    "ubuntu16"                  // ClientId需要唯一
  9 #define UserName    "ubuntu16"                  // 用户名
 10 #define PassWord    "123456"                    // 用户名对应的密码
 11 
 12 // 失去连接回调函数
 13 void connect_lost(void *context, char *cause)
 14 {
 15     printf("Connection lost,The reason: %s \n",cause);
 16 }
 17 
 18 // 收到主题信息回调函数
 19 int message_arrived(void *context, char *topicName, int topicLen, MQTTClient_message *message)
 20 {
 21     printf("Receive topic: %s, message data: \n", topicName);
 22     printf("%.*s\n", message->payloadlen, (char*)message->payload);
 23     MQTTClient_freeMessage(&message);
 24     MQTTClient_free(topicName);
 25     return 1;
 26 }
 27 
 28 // 主题发布成功回调函数
 29 void delivery_complete(void *context, MQTTClient_deliveryToken dt)
 30 {
 31     printf("publish topic success,token = %d \n", dt);
 32 }
 33 
 34 int main(int argc, char* argv[])
 35 {
 36     // 1、定义一个MQTT客户端结构体指针
 37     MQTTClient client;
 38 
 39     // 2、创建一个MQTT客户端
 40     int rc;
 41     if ((rc = MQTTClient_create(&client, MQTT_Uri, ClientId, MQTTCLIENT_PERSISTENCE_NONE, NULL)) != MQTTCLIENT_SUCCESS)
 42     {
 43         printf("Failed to create client, return code %d\n", rc);
 44         exit(EXIT_FAILURE);
 45         goto exit;
 46     }
 47 
 48     // 3、创建一个MQTT连接配置结构体，并配置其参数
 49     MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
 50     conn_opts.username = UserName;          // 用户名 
 51     conn_opts.password = PassWord;          // 用户名对应的密码
 52     conn_opts.keepAliveInterval = 60;       // 心跳时间
 53     conn_opts.cleansession = 1;             // 清除会话
 54     
 55     // 4、设置MQTT连接时的回调函数
 56     if ((rc = MQTTClient_setCallbacks(client, NULL, connect_lost, message_arrived, delivery_complete)) != MQTTCLIENT_SUCCESS)
 57     {
 58         printf("Failed to set callbacks, return code %d\n", rc);
 59         rc = EXIT_FAILURE;
 60         goto destroy_exit;
 61     }
 62 
 63     // 5、开始连接到MQTT服务器
 64     if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS)
 65     {
 66         printf("Failed to connect, return code %d\n", rc);
 67         exit(EXIT_FAILURE);
 68         goto destroy_exit;
 69     }
 70 
 71     // 6、定义一个主题消息存储结构体
 72     MQTTClient_message pubmsg = MQTTClient_message_initializer;
 73     char mag_data[] = "I am Ubuntu16.";
 74     pubmsg.payload = mag_data;
 75     pubmsg.payloadlen = (int)strlen(mag_data);
 76     pubmsg.qos = 1;                 // qos等级为1 
 77     pubmsg.retained = 0;            // 服务器不保留消息
 78     MQTTClient_deliveryToken token; // 标记MQTT消息的值，用来检查消息是否发送成功
 79 
 80     // 7、发布主题信息
 81     if ((rc = MQTTClient_publishMessage(client, "ubuntu16_publish", &pubmsg, &token)) != MQTTCLIENT_SUCCESS)
 82     {
 83         printf("Failed to publish message, return code %d\n", rc);
 84         exit(EXIT_FAILURE);
 85     }
 86 
 87     // 8、订阅主题
 88     if ((rc = MQTTClient_subscribe(client, "ubuntu16_subscribe", 1)) != MQTTCLIENT_SUCCESS)
 89     {
 90         printf("Failed to subscribe, return code %d\n", rc);
 91         rc = EXIT_FAILURE;
 92     }
 93 
 94     // 9、等待输入‘Q‘或‘q‘退出
 95     printf("Press Q or q + <Enter> to quit\n\n");
 96     int ch;
 97     do
 98     {
 99             ch = getchar();
100     } while (ch!=‘Q‘ && ch != ‘q‘);
101 
102     if ((rc = MQTTClient_unsubscribe(client, "ubuntu16_subscribe")) != MQTTCLIENT_SUCCESS)
103     {
104             printf("Failed to unsubscribe, return code %d\n", rc);
105             rc = EXIT_FAILURE;
106     }
107 
108     // 10、断开连接
109     if ((rc = MQTTClient_disconnect(client, 10000)) != MQTTCLIENT_SUCCESS)
110     {
111         printf("Failed to disconnect, return code %d\n", rc);
112         rc = EXIT_FAILURE;
113     }
114 
115 destroy_exit:
116     MQTTClient_destroy(&client);
117 exit:
118     return rc;
119 }