Re: New precondition fields and caching

Poul-Henning Kamp <phk@phk.freebsd.dk> Mon, 07 September 2020 07:04 UTC

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To: "Martin Thomson" <mt@lowentropy.net>
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From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
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Subject: Re: New precondition fields and caching
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--------
Martin Thomson writes:

> Assuming that interpretation is valid, how is this reconciled with existing
> uses of validation?  If-None-Match and If-Modified-Since specifically, which
> never in practice get recorded in Vary (at least not as far as I can tell).
> Is it that we effectively bless these fields and require caches to understand 
> them?

I think the answer is yes, but with the footnote that Cache-Control
should also be set to mitigate downright disasters, if an intermediary
does not grok If-*


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.