p_civil_aviation_mqtt/cpp/main.cpp

//
// Created by zwsd
//
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <fstream>
#include <iostream>
#include <list>
#include <map>
#include <memory>
#include <set>
#include <sstream>
#include <string>
#include <vector>

#include "MQTTClient.h"
#include "config.hpp"

using namespace std;
using namespace nlohmann;
using namespace iflytop;

typedef struct {
  string address;
  string username;
  string password;
  string clientid;
  int    qos;
  string topic;
  int    timeout;
} mqtt_config_t;

shared_ptr<MQTTConfig> g_mqtt_config;

static void publish(MQTTClient client, char *topic, char *payload) {
  MQTTClient_message message = MQTTClient_message_initializer;
  message.payload            = payload;
  message.payloadlen         = strlen(payload);
  message.qos                = g_mqtt_config->getQos();
  message.retained           = 0;
  MQTTClient_deliveryToken token;
  MQTTClient_publishMessage(client, topic, &message, &token);
  MQTTClient_waitForCompletion(client, token, g_mqtt_config->getTimeout());
  printf("Send `%s` to topic `%s` \n", payload, g_mqtt_config->getTopic().c_str());
}
static int on_message(void *context, char *topicName, int topicLen, MQTTClient_message *message) {
  char *payload = (char *)message->payload;
  printf("Received `%s` from `%s` topic \n", payload, topicName);
  MQTTClient_freeMessage(&message);
  MQTTClient_free(topicName);
  return 1;
}
int main(int argc, char *argv[]) {
  int        rc;
  MQTTClient client;
  MQTTConfig mqttConfig;

  g_mqtt_config = make_shared<MQTTConfig>();
  // 从文件中读取配置
  g_mqtt_config->initialize("mqtt_config.json");
  // 打印配置
  printf("mqtt_config.json: \n%s\n", g_mqtt_config->dump().c_str());
  // 创建客户端
  MQTTClient_create(&client, g_mqtt_config->getAddress().c_str(), g_mqtt_config->getClientid().c_str(), 0, NULL);
  MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
  conn_opts.username                  = g_mqtt_config->getUsername().c_str();
  conn_opts.password                  = g_mqtt_config->getPassword().c_str();
  // 设置回调函数
  MQTTClient_setCallbacks(client, NULL, NULL, on_message, NULL);
  // 连接到MQTT Broker
  if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) {
    printf("Failed to connect, return code %d\n", rc);
    exit(-1);
  } else {
    printf("Connected to MQTT Broker!\n");
  }
  // 订阅主题
  MQTTClient_subscribe(client, g_mqtt_config->getTopic().c_str(), g_mqtt_config->getQos());
  char payload[23];
  for (int i = 0; i < 100; i += 1) {
    snprintf(payload, 23, "{\"RunningState\": \"%d\"}", i);
    // 发布消息
    publish(client, (char *)g_mqtt_config->getTopic().c_str(), payload);
    sleep(1);
  }
  // 取消订阅
  MQTTClient_disconnect(client, g_mqtt_config->getTimeout());
  // 销毁客户端
  MQTTClient_destroy(&client);

  return 0;
}