p_civil_aviation_mqtt/c/main.c

#include "stdlib.h"
#include "string.h"
#include "unistd.h"
#include "MQTTClient.h"

#define ADDRESS "mqtt://iot-06z00dtdbnukzsk.mqtt.iothub.aliyuncs.com:1883"
#define USERNAME "mh_2&iekhmHv4wIC"
#define PASSWORD "8491b7d3391d51f40120bb9d81a4b713c624ce7beb216b9d37076508ac6e7446"
#define CLIENTID "iekhmHv4wIC.mh_2|securemode=2,signmethod=hmacsha256,timestamp=1680575050297|"
#define QOS 0
#define TOPIC "/sys/iekhmHv4wIC/mh_2/thing/event/property/post"
#define TIMEOUT 10000L

void publish(MQTTClient client, char *topic, char *payload)
{
    MQTTClient_message message = MQTTClient_message_initializer;
    message.payload = payload;
    message.payloadlen = strlen(payload);
    message.qos = QOS;
    message.retained = 0;
    MQTTClient_deliveryToken token;
    MQTTClient_publishMessage(client, topic, &message, &token);
    MQTTClient_waitForCompletion(client, token, TIMEOUT);
    printf("Send `%s` to topic `%s` \n", payload, TOPIC);
}

int on_message(void *context, char *topicName, int topicLen, MQTTClient_message *message)
{
    char *payload = 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;

    MQTTClient_create(&client, ADDRESS, CLIENTID, 0, NULL);
    MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
    conn_opts.username = USERNAME;
    conn_opts.password = PASSWORD;
    MQTTClient_setCallbacks(client, NULL, NULL, on_message, NULL);
    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");
    }
    // subscribe topic
    MQTTClient_subscribe(client, TOPIC, QOS);
    char payload[23];
    for (int i = 0; i < 100; i += 1)
    {
        // publish message to broker
        snprintf(payload, 23, "{\"RunningState\": \"%d\"}", i);
        publish(client, TOPIC, payload);
        sleep(1);
    }
    MQTTClient_disconnect(client, TIMEOUT);
    MQTTClient_destroy(&client);
    return rc;
}