Re: draft-ietf-httpbis-digest-headers: Digests and Conditional Requests

Mark Nottingham <mnot@mnot.net> Thu, 09 July 2020 05:31 UTC

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From: Mark Nottingham <mnot@mnot.net>
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Date: Thu, 9 Jul 2020 15:27:55 +1000
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Subject: Re: draft-ietf-httpbis-digest-headers: Digests and Conditional Requests
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> On 8 Jul 2020, at 6:28 pm, Julian Reschke <julian.reschke@gmx.de> wrote:
> 
> ...already covered by "If". I would prefer using something that is
> already defined, instead of having to mint two more header fields (we'd
> need both "If-Hash" and "If-Not-Hash", right?).

The problem is that it's not obvious what parts of If will need to be implemented to interoperate for a particular use case; will they need to support entity-tags too? What about Resource-Tags? The ability to put lists of conditions with varying aspects? Different URI schemes? It's actually a quite complex mechanism.

To me, it's much more straightforward to define a new header (or headers) to meet the use case in hand, with some modest affordance for extensibility. It would also remove the need to mint yet another customer parser if Structured Fields were used.

Cheers,

--
Mark Nottingham   https://www.mnot.net/