[Question] Observation of parent object

[horeich]

Question

Hello,

I'm currently connection to leshan server with a custom client and the following question arised:

How should I handle the case that leshan is sending me a observe request on a parent object or object instance?

For example

Observe /1/0/1 (server)
Notify 1/0/1 (client)
...
...
Observe /1 (server)
Notify /1/0/1 + Notify /1 **OR** only Notify /1 (client)

In other words: does a Notify on the parent object/instance override resource observe or does it append?

I couldn't find a specific description of that case it in the documentation.

Thanks in advance.

Best, Andy

[sbernard31]

I'm currently connection to leshan server with a custom client

I'm not sure if your custom client is a custimized leshan client or something completely different. (but maybe we don't care :sweat_smile: )

About your scenario, my understanding is it should behave like this :

Observe /1/0/1 (server)
Notify 1/0/1 (client)
...
...  (let's suppose you never cancel the observe on /1/0/1)
...
Observe /1 (server)
Notify /1 (client)  (here we just answer to the observe request  so we only send a notify for /1
... 
... (let's suppose that /1/0/1 resource changed
...
Notify /1/0/1 + Notify /1 (client)
... 
... (let's suppose that /1/0/2 resource changed
...
Notify /1 (client)

In other words: does a Notify on the parent object/instance override resource observe or does it append?

This is 2 different/unrelated observe relation.

If you need to double check how your device should behave concerning observation, you could have a look at : https://www.rfc-editor.org/rfc/rfc7641

[horeich]

Thank you! My example wasn't detailed enough but I think you've got what I meant. I just wasn't sure about the redundancy when observing /1/0/1 and /1. And you're right the origin of this redundancy lies in the underlying protocol. Obviously, I must send both /1/0/1 and /1 because if I sent only /1 I'd violate protocol as it's both CoAP Acknowledgements to the original Observe Request.

Yes, I'm not using Leshan on client side.

Thanks again for your prompt answer, can be closed.

[sbernard31]

You're welcome :wink: