Re: [Ace] Embedded Content Types

Peter van der Stok <> Thu, 21 February 2019 08:12 UTC

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Date: Thu, 21 Feb 2019 09:12:30 +0100
From: Peter van der Stok <>
To: Jim Schaad <>
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Subject: Re: [Ace] Embedded Content Types
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For me the est-coaps solution with different URIs is a good one.
as suggested by Carsten, /skg/ctnumbers seems straightforward.
In the return of /.well-known/core, the CT hints will help. No need to
define multiple content-format combinations.

Jim Schaad schreef op 2019-02-20 18:58:

> The CoRE working had an interesting virtual meeting this morning (my time)
> where the main topic of discussion was how to deal with embedded content
> types.  This is a current problem that needs to be addressed with the EST
> document which is currently trying to deal with last call comments.  The log
> from the meeting can be found at
> The takeaway from this that I got was:
> 1.  There is a real problem and we need to figure out the best ways to try
> and deal with this in a generic manner.   This is a problem not only here,
> but it the Publish/Subscribe CoRE document and in many other cases that we
> can see.
> 2.  We are not going to get a general solution immediately so EST needs to
> look at  doing something now.
> 3.  A couple of different possibilities where discussed that could be used:
> a)  Return a list of links rather than a multipart content and let the
> client sort through that list and download the things that they want.  This
> is a purely reactive solution.
> b) Use a different URI to ask for the different options.  This could be done
> either by the use of a different URI path or by the use of a query
> parameter.
> c) Register a different content type for each of the possible return values.
> There was a general preference for the use of a different URI as being the
> solution that should be used today.  The idea of registering multiple
> content types was generally disliked as it does not really extend well.
> There was no specific preference on whether the use of a different URI path
> or a query parameter would be preferred.  The use of a different URI would
> allow for better discovery of capabilities.  
> The idea of listing nested content types in the 'ct' link type was also
> universally disliked.
> The CoRE, T2TRG and other forums are expected to continue discussions on
> this topic in different contexts such as Pub-Sub and CoRAL. To come up with
> both proactive and reactive solutions to the more general problem.
> Jim
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