Re: [httpbis] #432: Review Cachability of Status Codes WRT "Negative Caching"

[Mark Nottingham <[e-mail]>]

OK, since there's been no more discussion, I'm going to go ahead and mark the following as cacheable:

	• 204 (No Content)
	• 404 (Not Found)
	• 405 (Method Not Allowed)
	• 414 (Request URI Too Long)
	• 501 (Not Implemented)

Cheers,



On 18/02/2013, at 11:12 AM, Mark Nottingham <[e-mail]> wrote:

> I haven't seen any discussion, and this is our last ticket (at least for the moment).
> 
> So, I'll make a proposal; we should identify the following additional status codes as cacheable (i.e., eligible for using a heuristic to determine freshness, in the absence of explicit information);
> 
> 	• 204 (No Content)
> 	• 404 (Not Found)
> 	• 405 (Method Not Allowed)
> 	• 414 (Request URI Too Long)
> 	• 501 (Not Implemented)
> 	• 502 (Bad Gateway)
> 	• 503 (Service Unavailable)
> 	• 504 (Gateway Timeout)
> 
> Note that I'm *not* proposing the following, even though they are negatively cached by some implementations, as I suspect doing so may cause interop problems:
> 
> 	• 400 (Bad Request)
> 	• 403 (Forbidden)
> 	• 500 (Internal Server Error)
> 
> Thoughts?
> 
> 
> 
> On 11/02/2013, at 5:28 PM, Mark Nottingham <[e-mail]> wrote:
> 
>> ... and this is the ticked I just promised:
>> 
>> Begin forwarded message:
>> 
>>> From: "httpbis" <[e-mail]>
>>> Subject: [httpbis] #432: Review Cachability of Status Codes WRT "Negative Caching"
>>> Date: 11 February 2013 5:27:44 PM AEDT
>>> To: [e-mail]
>>> Reply-To: [e-mail]
>>> 
>>> #432: Review Cachability of Status Codes WRT "Negative Caching"
>>> ----------------------------+-----------------------------
>>> Reporter:  [e-mail]  |      Owner:
>>>   Type:  design          |     Status:  new
>>> Priority:  normal          |  Milestone:  unassigned
>>> Component:  p6-cache        |   Severity:  In WG Last Call
>>> Keywords:                  |     Origin:  #223
>>> ----------------------------+-----------------------------
>>> Currently, the following status codes are defined as cacheable -- that is,
>>> able to be stored without any explicit freshness information:
>>> 
>>> - 200 (OK)
>>> - 203 (Non-Authoritative Information)
>>> - 206 (Partial Content)
>>> - 300 (Multiple Choices)
>>> - 301 (Moved Permanently)
>>> - 410 (Gone)
>>> 
>>> However, many caches store other status codes (often called "Negative
>>> Caching")
>>> 
>>> For example, both Squid and Traffic Server (which have considerable market
>>> share, and form the basis of many other implementations) negatively cache
>>> the following status codes:
>>> 
>>> - 204 (No Content)
>>> - 400 (Bad Request)
>>> - 403 (Forbidden)
>>> - 404 (Not Found)
>>> - 405 (Method Not Allowed)
>>> - 414 (Request URI Too Long)
>>> - 500 (Internal Server Error)
>>> - 501 (Not Implemented)
>>> - 502 (Bad Gateway)
>>> - 503 (Service Unavailable)
>>> - 504 (Gateway Timeout)
>>> 
>>> While some of these may be bad to cache by default (in particular, 400 and
>>> 500), others may make sense: for example, 204 seems straightforward, and
>>> 404 seems high-value.
>>> 
>>> The major concern here is making semantic changes to the protocol.
>>> 
>>> -- 
>>> Ticket URL: <http://trac.tools.ietf.org/wg/httpbis/trac/ticket/432>
>>> httpbis <http://tools.ietf.org/wg/httpbis/>
>>> 
>> 
>> --
>> Mark Nottingham   http://www.mnot.net/
>> 
>> 
>> 
>> 
> 
> --
> Mark Nottingham   http://www.mnot.net/
> 
> 
> 
> 

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