[core] Simplify draft-ietf-core-comi-12.txt

[Carsten Bormann <[e-mail]>]

In the interim last Wednesday, we were seriously wondering why we need both GET/PUT/POST and FETCH/iPATCH for COMI.  The consensus of the room was that the easiest way to solve the problems with generating the URIs for GET/PUT/POST was to move over to FETCH/iPATCH completely.

I have created a first draft of this “simplified” version of core-comi.
No base64 encoding any more…
All CoAP method/content-format combinations that would have required base64-encoding instance identifiers on a URI have been removed.

GET/PUT/POST/DELETE are still in there for full datastore access.
I’m not sure about the use case for this, but since it doesn’t need instance identifiers in a URI, I left it in.  Please advise.

I also simplified the POST request for RPC/Action to carry application/yang-instances+cbor as a payload.
This was a single "application/yang-data+cbor; id=sid", but this is now no longer used by CORECONF (*) (and it doesn't carry an instance identifier).

event-streams are still fetched using GET as all the information that is needed is in
the event stream URI, but I don’t know a good way to do ?f= on event stream resources.  Should this be moved to FETCH as well?

(*) I don’t know how to do errors in the way COMI has done them before.
These don’t cleanly map to application/yang-instances+cbor, as there is no data node involved.  (By now, we have RFC 9290…  Does this help here?)

Please view the draft draft at:

https://core-wg.github.io/comi/simplify/draft-ietf-core-comi.html

A diff from main (~ -12) can be seen at:

https://author-tools.ietf.org/iddiff?url1=https://core-wg.github.io/comi/draft-ietf-core-comi.txt&url2=https://core-wg.github.io/comi/simplify/draft-ietf-core-comi.txt

Enjoy!

Grüße, Carsten