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From Zachary Zolton <zachary.zol...@gmail.com>
Subject Re: COUCHDB-190
Date Sat, 31 Jan 2009 21:14:02 GMT
Chris/Antony,

If we want to stop all caching, with a very generous helping of
backward compatibility, let's consider responding with the following
headers:

--------------------------------------------------------------------------------
  Date: <ServercurrentDate>
  Expires: Fri, 01 Jan 1990 00:00:00 GMT
  Pragma: no-cache
  Cache-control: no-cache, must-revalidate
--------------------------------------------------------------------------------

FYI, I found this article:
  http://code.google.com/p/doctype/wiki/ArticleHttpCaching


Cheers,

Zach



On Sat, Jan 31, 2009 at 1:01 AM, Chris Anderson <jchris@apache.org> wrote:
> On Fri, Jan 30, 2009 at 10:41 PM, Antony Blakey <antony.blakey@gmail.com> wrote:
>>
>> In the referenced m/l discussion about the issue of GET vs. POST, the point
>> was made that if there are problems with GET for UUIDs, then there are going
>> to be similar problems for GETs of documents, views without params,
>> /_config, /_stats etc, and attachments.
>>
>
> True, but in those cases at least the failure mode manifests itself in
> ways other than rejecting later updates. Also, in those cases there
> are conditions when it's OK to cache. In the _uuids case, one should
> never ever cache.
>
>> I would have thought that GET of UUIDs would therefore be OK as long as it
>> was at least as good cache-header-wise as the other GET operations in
>> CouchDB.
>>
>
> Good point, I guess I'm thinking it doesn't hurt to be as uncacheable
> as possible in this case. But you raise the point that bad clients are
> going to get strange errors regardless of what we do on this question,
> so being helpful to nonconforming clients is of limited value.
>
> @ZDZolton: testing for
>
> Cache-Control: must-revalidate
>
> is important. This snippet from the RFC:
>
> (I.e., the cache MUST do an end-to-end revalidation every time, if,
> based solely on the origin server's Expires or max-age value, the
> cached response is stale.)
>
> suggests we should also test for either Expires or max-age, to be on
> the safe side.
>
> Chris
>
> --
> Chris Anderson
> http://jchris.mfdz.com
>

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