local.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "MQTTClient.h"

#define ADDRESS    "ssl://192.168.12.175:8883"
#define CLIENTID   "ClientDevice"
#define TOPIC      "client/data"
#define QOS        1
#define TIMEOUT    10000L

int main()
{
    MQTTClient client;
    MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
    int rc;

    MQTTClient_create(&client, ADDRESS, CLIENTID, MQTTCLIENT_PERSISTENCE_NONE, NULL);
    
    MQTTClient_SSLOptions ssl_opts = MQTTClient_SSLOptions_initializer;
    ssl_opts.enableServerCertAuth = 1;
    ssl_opts.trustStore = "ca.pem";
    ssl_opts.keyStore = "client.pem";
    ssl_opts.privateKey = "client.key";

    conn_opts.ssl = &ssl_opts;
    conn_opts.keepAliveInterval = 20;
    conn_opts.cleansession = 1;

    if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) {
        printf("Failed to connect, return code %d\n", rc);
        return rc;
    }

    char payload[] = "temperature=25";
    MQTTClient_message pubmsg = MQTTClient_message_initializer;
    pubmsg.payload = payload;
    pubmsg.payloadlen = strlen(payload);
    pubmsg.qos = QOS;
    pubmsg.retained = 0;

    MQTTClient_deliveryToken token;
    MQTTClient_publishMessage(client, TOPIC, &pubmsg, &token);
    MQTTClient_waitForCompletion(client, token, TIMEOUT);

    printf("Message '%s' sent\n", payload);

    MQTTClient_disconnect(client, 10000);
    MQTTClient_destroy(&client);
    return 0;
}