mqtt simple data_publish

[linh]

Hi,

I am trying to send a test message in Server through mqtt and used the mqtt_simple example for that.

For the test I insert data_publish() function in main() like following, but in my Server there are no message arrived. I tested my Server, the Server ist ok and can received mqtt message.

Did I missunderstand something. Why did't it work?

 

Regards,

Linh

[linh]

After many time trying, I realize that the function data_publish() have to be located after the commands in While(1) Loop so that the data can send. My new Code Looks like this

//while (1) {
                printk("poll(&fds, 1, K_SECONDS(CONFIG_MQTT_KEEPALIVE));\n");
		err = poll(&fds, 1, K_SECONDS(CONFIG_MQTT_KEEPALIVE));
		if (err < 0) {
			printk("ERROR: poll %d\n", errno);
			//break;
		}
                printk("mqtt_live\n");
		err = mqtt_live(&client);
		if (err != 0) {
			printk("ERROR: mqtt_live %d\n", err);
			//break;
		}

		if ((fds.revents & POLLIN) == POLLIN) {
                        printk("mqtt_input\n");
			err = mqtt_input(&client);
			if (err != 0) {
				printk("ERROR: mqtt_input %d\n", err);
				//break;
			}
		}

		if ((fds.revents & POLLERR) == POLLERR) {
			printk("POLLERR\n");
			//break;
		}

		if ((fds.revents & POLLNVAL) == POLLNVAL) {
			printk("POLLNVAL\n");
			//break;
		}
	//}
        data_publish(&client, MQTT_QOS_1_AT_LEAST_ONCE, "dataPu4", strlen("dataPu4"));

 

But I don't really understand what the commands in while(1){..} do. Do you know, what happend in the loop? and why data_publish() have to be located after this?

while (1) {

		err = poll(&fds, 1, mqtt_keepalive_time_left(&client));

		if (err < 0) {

			printk("ERROR: poll %d\n", errno);

			break;

		}



		err = mqtt_live(&client);

		if ((err != 0) && (err != -EAGAIN)) {

			printk("ERROR: mqtt_live %d\n", err);

			break;

		}



		if ((fds.revents & POLLIN) == POLLIN) {

			err = mqtt_input(&client);

			if (err != 0) {

				printk("ERROR: mqtt_input %d\n", err);

				break;

			}

		}



		if ((fds.revents & POLLERR) == POLLERR) {

			printk("POLLERR\n");

			break;

		}



		if ((fds.revents & POLLNVAL) == POLLNVAL) {

			printk("POLLNVAL\n");

			break;

		}

	}

[Heidi]

Hi!

I'm glad you solved the issue.

The commands in the while loop keep the MQTT connection alive. The poll() function keeps track of the time elapsed with regard to the keep_alive time that's set.

And the function mqtt_live() ensures the MQTT connection is kept alive.

Best regards,

Heidi