MQTT Example - Settings for publishing while subscribing?

RE: MQTT Example - Settings for publishing while subscribing?

Stian Røed Hafskjold — Thu, 20 Apr 2017 12:16:09 GMT

Please start a new thread, and link to this one.

RE: MQTT Example - Settings for publishing while subscribing?

g.joshi — Thu, 20 Apr 2017 11:54:55 GMT

Hey copied the code min main file but i have few issues:

In step 3 when i push button 2 LED 4 blinks instead of no activity.
In step 4 when i push button 4 it doesn´t subscribe and LD3 is off all the while.

I can add the code if want.

RE: MQTT Example - Settings for publishing while subscribing?

g.joshi — Wed, 19 Apr 2017 15:11:06 GMT

Hey copied the code min main file but i have few issues:

In step 3 when i push button 2 LED 4 blinks instead of no activity.
In step 4 when i push button 4 it doesn´t subscribe and LD3 is off all the while. I can add the code if want.

RE: MQTT Example - Settings for publishing while subscribing?

Stian Røed Hafskjold — Mon, 29 Aug 2016 12:49:20 GMT

Hi,

I made an example for both publishing and subscribing in the same example. It is based on mqtt publisher example and merged with the mqtt subscriber example. I added button 4 as the subscribing button, and LED 4 is toggling only if it receives a publish message from the broker.

LED1 lights up after connection
Push Button1 to connect to broker. LED2 turns on.
Push Button2 to publish. No activity on LEDs
Push Button4 to subscribe. LED3 turns on.
Push Button2 to publish. You should now see activity on LED4. This means that the kit is both publishing and subscribing to the same topic "led/state".

Replace the content of the main.c file in the mqtt publisher example with this one: main.c

RE: MQTT Example - Settings for publishing while subscribing?

MANGO — Wed, 10 Aug 2016 14:31:03 GMT

Well, I tested both the standalone subscriber project and standalone publisher project.

The standalone subscriber project triggered the breakpoint at case MQTT_EVT_PUBLISH:.

However, my merged project does not.

Then how about using "diff"? Can you upload the merged application, the main.c file?

Then I can "diff" (compare codes) together and check the problem.

-Best Regards, Mango

RE: MQTT Example - Settings for publishing while subscribing?

FormerMember — Tue, 09 Aug 2016 10:27:19 GMT

If you first try the subscriber and publisher examples separately, and test them like described in the documentation, and know that they work, then you know that the setup is correct and it will be easier to debug the subscriber&publisher project.

RE: MQTT Example - Settings for publishing while subscribing?

MANGO — Tue, 09 Aug 2016 09:01:13 GMT

Hi, Kristin.

I haven't tried the standalone subscriber project. I will do it soon.

About the "Just to double check, the publisher is publishing on the topic "led/state"?" and "The publisher that is publishing on "led/state", does it have the same broker port? "1883" for non-secure port, for instance?" ,

yes, it is.

The merged application (publish + subscribe) is both using port 1883.

Thanks to Stian's help, the Raspberry Pi (RPi) is using the 6tunnel to forward packets to IPv4.

The application is publishing to topic "led/state".

Come to think of it, the application subscribed to the same topic.

So I thought MQTT_EVT_PUBLISH event will be triggered after publishing.

While trying the standalone subscriber project, are you recommending me to subscribe to a different topic?

For instance, publish to "led/state" but subscribe to "test".

Should I try it this way and see how it goes?

-Best Regards, Mango

RE: MQTT Example - Settings for publishing while subscribing?

FormerMember — Tue, 09 Aug 2016 08:35:18 GMT

Does your subscriber code works in a standalone subscriber project?

Just to double check, the publisher is publishing on the topic "led/state"?

Does the publisher in you subscriber&publisher project work?

The publisher that is publishing on "led/state", does it have the same broker port? "1883" for non secure port, for instance?

RE: MQTT Example - Settings for publishing while subscribing?

MANGO — Thu, 04 Aug 2016 12:04:40 GMT

Well, I added the code by referring the subscriber example.

However, even though the error code is 0 when calling mqtt_subscribe,

the breakpoint didn't hit the case MQTT_EVT_PUBLISH: when I publish data to the topic "led/state".

What seems to be the problem?

-Best Regards, Mango

RE: MQTT Example - Settings for publishing while subscribing?

FormerMember — Mon, 01 Aug 2016 08:43:49 GMT

Yes, the IoT SDK supports subscribing to multiple topics.

RE: MQTT Example - Settings for publishing while subscribing?

MANGO — Mon, 01 Aug 2016 08:34:54 GMT

Great, while trying your suggestion I have an additional question.

Does the IoT SDK support subscribing MQTT multiple topics?

I'm curious whether the handler can handle when the application subscribes topic "A", "B", and "C".

-Best Regards, Mango

RE: MQTT Example - Settings for publishing while subscribing?

FormerMember — Mon, 01 Aug 2016 08:25:51 GMT

Yes, it is possible to combine a MQTT publisher and subscriber in one application. In order to do so, the publisher and subscriber functionality has to be "merged" into one application. The settings that you need to include in the publisher example are the subscriber specific settings like APP_MQTT_SUBSCRIPTION_PKT_ID and APP_MQTT_SUBSCRIPTION_TOPIC for instance.