Re: [SQU] 304response does not override cached headers.

On Sun, 20 Aug 2000, Hirohiko Nakano wrote:

> If the conditional GET used a strong cache validator (see section
> 13.3.3), the response SHOULD NOT include other entity-headers.
> Otherwise (i.e., the conditional GET used a weak validator), the
> response MUST NOT include other entity-headers; this prevents
> inconsistencies between cached entity-bodies and updated headers.
>
> *** This section does not mention how to handle general headers. I
> think Pragma header is allowed in 304responses. ***

Yes, looks like you are right. I missed the "entity-" qualification when
reading the specs. FWIW, I have seen several non-Squid caches that would
not update _extension_ headers on 304 replies so you probably should not
rely on caches complying with this aspect of HTTP without double
checking. (Pragma is not an extension header, but I would not be
surprised if caches do not update it either).

While "reasonable", the requirement to update headers is often costly
and cumbersome to implement so I guess that many cache designers may
simply ignore it for now.

Alex.

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