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Re: [core] Spencer Dawkins' Discuss on draft-ietf-core-etch-03: (with DISCUSS and COMMENT)

Carsten Bormann <cabo@tzi.org> Thu, 13 October 2016 11:15 UTC

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Date: Thu, 13 Oct 2016 13:16:03 +0200
From: Carsten Bormann <cabo@tzi.org>
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To: Alexey Melnikov <aamelnikov@fastmail.fm>
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Cc: core-chairs@ietf.org, draft-ietf-core-etch@ietf.org, Spencer Dawkins <spencerdawkins.ietf@gmail.com>, core@ietf.org, The IESG <iesg@ietf.org>
Subject: Re: [core] Spencer Dawkins' Discuss on draft-ietf-core-etch-03: (with DISCUSS and COMMENT)
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Alexey Melnikov wrote:
> Does this mean that a client that wants doesn't care about idempotency
> of its request might need to try PATCH, then discover that it is not
> supported and then retry iPATCH?

How does it know that the server supports one of these methods (PATCH,
iPATCH) in the first place, and what media types to use with one of
these?  This is usually found out using discovery (for an example, see
the form relations concept introduced in draft-hartke-core-apps).  This
discovery would also tell the client which specific method to use, so
there is no need for trial and error.

What we could add is a recommendation for servers to always support both
methods (that is not hard to do, because what follows), and emphasize
that there is no particular onus *on the server* to check the client's
intention that the request be idempotent.

Grüße, Carsten

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