Skip to main content

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [List Home]
Re: [mosquitto-dev] Question about publishing to an MQTT brokerusing TLS

    Hi Roger.

    I did call mosquitto_lib_init(). Since the test program isn't very long I've included it below.

    I included the sleep() call because I thought the callbacks would be called asynchronously, and wanted to see if I was actually getting the connect completion before doing the publish. I notice pub_client.c actually does the mosquitto_publish from within the connect callback. I expect I'll so something similar to avoid races, but I didn't make that change because I noticed the connect wasn't completing.

    - Mark


      #include <stdio.h>
      #include <string.h>

      #include <mosquitto.h>

      #define cafile "./rootCA.pem"
      #define certfile "./cert.pem"
      #define keyfile "./private-key.pem"
      #define host ""
      #define port 8883
      #define qos 0
      #define topic "topic/test"
      #define message "{\"msg\" : \"Hello ... World\"}"

      void connect_callback(struct mosquitto *mosq, void *obj, int result) {
      printf("Connect callback: \n");

      void disconnect_callback(struct mosquitto *mosq, void *obj, int rc) {
      printf("Disconnect callback: \n");

      void log_callback(struct mosquitto *mosq, void *obj, int level, const char *str) {
      printf("%s\n", str);

      void publish_callback(struct mosquitto *mosq, void *obj, int mid) {
      printf("Publish callback: \n");

      int main (int argc, char *argv[]) {
      char idstr[64];
      struct mosquitto *mosq = NULL;
      // int mqtt_version = 3; /* MQTT_PROTOCOL_V31 */
      int mqtt_version = 4; /* MQTT_PROTOCOL_V311 */
      int status;

      /* Initialize needed storage. */
      snprintf(idstr, sizeof(idstr), "mosquitto_%d", getpid());

      /* Initialize mosquitto. */

      /* Create a new mosquitto instance. */
      mosq = mosquitto_new(idstr, true, NULL);
      if (!mosq) {
      printf("Error creating mosquitto instance\n");
      return 1;
      printf("New mosquitto instance created\n");

      /* Connect up all the callback functions. */
      mosquitto_log_callback_set(mosq, log_callback);
      mosquitto_connect_callback_set(mosq, connect_callback);
      mosquitto_disconnect_callback_set(mosq, disconnect_callback);
      mosquitto_publish_callback_set(mosq, publish_callback);
      printf("Callback setup complete\n");

      /* Use TLS for communications. */
      status = mosquitto_tls_set(mosq, cafile, NULL,
      certfile, keyfile, NULL);
      if (status) {
      printf("Error (%d) configuring TLS.\n", status);
      return 2;
      printf("TLS setup complete\n");

      /* Maximum inflight messages. */
      status = mosquitto_max_inflight_messages_set(mosq, 20);
      if (status) {
      printf("Error (%d) setting max inflight message count.\n", status);
      return 6;
      printf("Max inflight count set\n");

      /* Set mosquitto options. */
      status = mosquitto_opts_set(mosq, MOSQ_OPT_PROTOCOL_VERSION,
      if (status) {
      printf("Error (%d) setting mosquitto options.\n", status);
      return 7;
      printf("Mosquitto options set\n");

      /* Connect to the broker. */
      status = mosquitto_connect_bind(mosq, host, port, 60, NULL);
      if (status) {
      printf("Error (%d) connecting to broker.\n", status);
      return 3;


      /* Publish the message */
      status = mosquitto_publish(mosq, NULL, topic,
      strlen(message), message,
      qos, false);
      if (status) {
      printf("Error (%d) publishing message.\n", status);
      return 4;

      return 0;

Back to the top