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Re: i37 - Vary and non-existant headers

From: Jamie Lokier <jamie@shareable.org>
Date: Thu, 15 Nov 2007 08:51:53 +0000
To: Henrik Nordstrom <henrik@henriknordstrom.net>
Cc: Adrien de Croy <adrien@qbik.com>, "'HTTP Working Group'" <ietf-http-wg@w3.org>
Message-ID: <20071115085153.GA18577@mail.shareable.org>

Henrik Nordstrom wrote:
> Vary and the cache rules around Vary do not care about semantics of
> headers. Just their existence and value.  Vary is a selector telling
> caches which headers of the request need to be included in the
> comparison when comparing two requests. 
> The logic actually selecting the correct variant depending on the
> request content is all deferred to the web server, except when there is
> exact matches filtered by Vary.

What about whitespace differences (e.g. leading/trailing whitespace,
whitespace following the header name colon), multi-line breaks, and
multiple occurrences of the same header?

Does exact means _exactly_ in all those respects, or is it acceptable
for a cache to canonicalise certain things, like converting multiple
occurences of a header to a single header by joining with ", " (or
","), converting multi-line headers to single-line, and stripping
leading/trailing whitespace from the header value?

-- Jamie
Received on Thursday, 15 November 2007 08:52:07 UTC

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