- From: Julian Reschke <julian.reschke@gmx.de>
- Date: Wed, 02 Jun 2010 10:45:54 +0200
- To: Mark Nottingham <mnot@mnot.net>
- CC: HTTP Working Group <ietf-http-wg@w3.org>, Jamie Lokier <jamie@shareable.org>
On 02.06.2010 07:55, Mark Nottingham wrote: > p6 currently states: > > The "Cache-Control" general-header field is used to specify directives that > &MUST; be obeyed by all caches along the request/response chain. > > but as Jamie points out in<http://trac.tools.ietf.org/wg/httpbis/trac/ticket/168>, this doesn't work so well with extension CC directives. > > I think the intent is preserved with: > > """ > The "Cache-Control" general-header field is used to specify directives for caches along the request/response chain. HTTP/1.1 caches > MUST obey the requirements of the Cache-Control directives defined in this section. See [ref to CC extensions] for information about how Cache-Control directives defined elsewhere are handled. > """ > > Thoughts? Looks good to me. That being said, I rearranged the sentences and ended up with: 3.2. Cache-Control The "Cache-Control" general-header field is used to specify directives for caches along the request/response chain. Such cache directives are unidirectional in that the presence of a directive in a request does not imply that the same directive is to be given in the response. HTTP/1.1 caches MUST obey the requirements of the Cache-Control directives defined in this section. See Section 3.2.3 for information about how Cache-Control directives defined elsewhere are handled. Note: HTTP/1.0 caches might not implement Cache-Control and might only implement Pragma: no-cache (see Section 3.4). Cache directives MUST be passed through by a proxy or gateway application, regardless of their significance to that application, since the directives might be applicable to all recipients along the request/response chain. It is not possible to target a directive to a specific cache. Cache-Control = "Cache-Control" ":" OWS Cache-Control-v Cache-Control-v = 1#cache-directive cache-directive = cache-request-directive / cache-response-directive cache-extension = token [ "=" ( token / quoted-string ) ] (see <http://trac.tools.ietf.org/wg/httpbis/trac/attachment/ticket/168/i168.diff>). Ticket 168 furthermore mentions: > Furthermore, the BNF doesn't make it clear that request and response directives shouldn't be intermixed; > > Cache-Control-v = 1#cache-directive > > cache-directive = cache-request-directive > > / cache-response-directive That could be addressed by saying: Cache-Control-v = 1#cache-request-directive / 1#cache-response-directive However, I'm not sure we need to express this as a syntactical constraint (and it also might confuse people with respect to whether this header uses the "list style" or not). Best regards, Julian
Received on Wednesday, 2 June 2010 08:46:36 UTC