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From Chris Anderson <jch...@apache.org>
Subject Re: COUCHDB-190
Date Sat, 31 Jan 2009 21:38:40 GMT
On Sat, Jan 31, 2009 at 1:14 PM, Zachary Zolton
<zachary.zolton@gmail.com> wrote:
> 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
> --------------------------------------------------------------------------------
>

sounds good to me. I'm +1 on including a patch that test for these
headers for _uuids GET requests

> 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
>>
>



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

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