[Cbor] draft-ietf-cbor-file-magic: Processing recommendations

Christian Amsüss <christian@amsuess.com> Wed, 21 April 2021 15:15 UTC

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Date: Wed, 21 Apr 2021 17:15:27 +0200
From: Christian =?iso-8859-1?Q?Ams=FCss?= <christian@amsuess.com>
To: draft-ietf-cbor-file-magic@ietf.org
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Subject: [Cbor] draft-ietf-cbor-file-magic: Processing recommendations
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Hello Michael,

looking at cbor-file-magic from the "implementing generic tools" (static
CoAP file server, downloading CoAP client) point of view, I'm wondering
whether anything actionable for these cases.

I'm tempted to do crazy things, serving content formats from recognized
CBOR protocol tags, and possibly stripping the tagging once transferred
into a Content-Format option, or doing the inverse when downloading into
a file. Turning down the crazy, these things may make more sense in an
opt-in fashion both on the server and on the client side. Going only
half the way and serving the content-format while also sending the full
data stream probably makes no sense (if the data was really intended to
be application/octet-stream, the server is already lying about the
content format, and stealing the inital bytes just adds to the charges).

Is there any recommendation on that topic that you'd deem sensible,
either in-document or just on the "it's been discussed on the list"
record?

(On the mapping between content formats and tags I'll have to revisit
the discussion history; I was under the impression that at some point
this was tied to content format numbers, as in "registering 2**16 tags
at once", but seems I was mistaken here).

BR
c

PS. Is bcp really the intended category for that document?

-- 
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  -- ancient saying