Re: [core] Pub/Sub update to use the core multipart content format

Michael Koster <michaeljohnkoster@gmail.com> Sat, 02 March 2019 23:23 UTC

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From: Michael Koster <michaeljohnkoster@gmail.com>
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Date: Sat, 2 Mar 2019 15:23:53 -0800
Cc: Carsten Bormann <cabo@tzi.org>, "core@ietf.org WG" <core@ietf.org>
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Subject: Re: [core] Pub/Sub update to use the core multipart content format
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OK, I read the multipart draft (expired?) For the no data case we will just send an empty multipart payload (cbor x80).

It seems like every implementation of pub/sub will be required to support only link-format and multipart. The subtype support will be on a topic basis and maybe a broker should have some way to list a set of supported subtopics that it can handle. To remind people, a coap pub/sub broker doesn't have any notion of "resource state" other than a stored representation.

Best regards,

Michael

> On Mar 2, 2019, at 5:27 AM, Michael Koster <michaeljohnkoster@gmail.com> wrote:
> 
> Hi,
> 
> I am editing the pub/sub draft today and thinking about the multipart content format as a way to provide a subscribe or retrieve response for the no data case.
> 
> It seems to require that the pub/sub client always support the multipart format, with no content being one of the format options signaled by something like "maybe".
> 
> Does this seem right to you also? Do we need to invent a new empty format code instead of a response code? 
> 
> Best regards,
> 
> Michael
> 
> 
> 
>