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From Chris Anderson <jch...@apache.org>
Subject Re: COUCHDB-190
Date Sat, 31 Jan 2009 06:29:37 GMT
On Fri, Jan 30, 2009 at 10:13 PM, Zachary Zolton
<zachary.zolton@gmail.com> wrote:
> JChris,
>
> Would testing for the this header be sufficient?
>
>  Cache-Control: must-revalidate
>

Part of the point of using POST was to avoid all the compatibility
questions with non-conforming user-agents. I understand that bending
over backwards for broken UA's is not the best way to go (hence my
interest in the patch) but I think we'd do well to go above and beyond
the spec here.

>From my bad-old days as an IE jockey, I seem to remember some stuff
about Pragma: no-cache. I'm not sure if we have a CouchDB policy about
supporting HTTP 1.0, but unless we can be sure that switching to GET
won't introduce some uncontrollable regressions for old or bad user
agents, I think we should at least continue to support POST as well as
GET.

Here's a pretty good summary of the problems with old IE versions and
GET caches:
http://www.quirksmode.org/blog/archives/2005/12/xmlhttp_notes_c.html

If you can convince me that it's safe just to do GET correctly in
2008, I'm happy to go through with the patch. Since duplicate uuids
have a hard-to-trace failure mode, and POST isn't causing any
pragmatic problems, the only reason I can see to move to GET is that
it's a good example it sets for other servers.

> Given the quotation:
>
>  "Servers SHOULD send the must-revalidate directive if and only if
> failure to revalidate a request on the entity could result in
> incorrect operation, such as a silently unexecuted financial
> transaction."
>
> From:
>
>  http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.4
>
>
> Cheers,
>
> ZDZolton
>
>
> On Fri, Jan 30, 2009 at 11:54 PM, Chris Anderson <jchris@apache.org> wrote:
>> On Fri, Jan 30, 2009 at 9:50 PM, Zachary Zolton
>> <zachary.zolton@gmail.com> wrote:
>>> So, I've had a patch there, for a few days. I'll provide explanation,
>>> if you want to commit...
>>>
>>
>> Thanks for the reminder. The only thing I'd ask for is adding to the
>> test suite, a verification that the proper cache control headers are
>> being sent. It may be that they already are, but since it's absolutely
>> crucial for correct client behavior, adding a test for it will ensure
>> that we don't face a future regression.
>>
>> Thanks,
>> Chris
>>
>> --
>> Chris Anderson
>> http://jchris.mfdz.com
>>
>



-- 
Chris Anderson
http://jchris.mfdz.com

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