Re: draft-ietf-httpbis-p6-cache-06

On 28/05/2009, at 1:31 AM, Brian Smith wrote:

> Thomas Broyer wrote:
>> Brian Smith <brian@briansmith.org> wrote:
>>> It's not invalid, but it doesn't mean anything. POST responses are
>>> never cacheable; caches must write POST requests through to the
>>> server, and a cache can't use a POST response to respond to a
>>> GET/HEAD request.

2616 says:
> Responses to this method are not cacheable, unless the response  
> includes appropriate Cache-Control or Expires header fields.



>> Even when the POST response has a Content-Location?
>
> There's nothing in RFC2616 or the latest HTTPbis drafts that says a  
> cached POST response can be returned in response to a GET/HEAD  
> request.

No, but there is accommodation for it; see p6 2.1 and 2.2, in  
particular the TODO note in the latter.


> Applying Postel's rule, a cache shouldn't return a cached POST  
> response to a GET/HEAD request, and servers shouldn't include Cache- 
> Control/Expires headers in POST responses. That should be explicit  
> in the specification.

There has been considerable discussion on this, and your conclusion  
wasn't suggested AFAIK, nor was it the direction we've chosen to move  
in. See:
    http://trac.tools.ietf.org/wg/httpbis/trac/ticket/139
    http://www.w3.org/mid/08345F97-7D4D-40AD-98E2- 
EF73E93C031F@mnot.net (entire thread)



--
Mark Nottingham     http://www.mnot.net/

Received on Tuesday, 2 June 2009 04:01:00 UTC