- From: Mark Nottingham <mnot@mnot.net>
- Date: Mon, 8 Jun 2009 10:33:26 +1000
- To: Jamie Lokier <jamie@shareable.org>
- Cc: Adrien de Croy <adrien@qbik.com>, Brian Smith <brian@briansmith.org>, HTTP Working Group <ietf-http-wg@w3.org>
Just FYI, we do have an open issue on these lines: http://trac.tools.ietf.org/wg/httpbis/trac/ticket/147 Cheers, On 08/06/2009, at 9:47 AM, Jamie Lokier wrote: > Adrien de Croy wrote: >> However order therefore is still important, so matching between >> >> Content-Language: en-nz, fr >> and >> Content-Language: fr, en-nz >> >> would fail, even though logically these are identical since order >> is not >> significant in the spec. I can understand this makes matching >> simpler >> (normalise and string compare), and probably shields against >> arbitrary >> selection algorithms (e.g. order-based) being used by the origin >> server, >> but it's not clear from the spec as to why, and anyone wanting to do >> things a bit "smarter" may consider doing a different sort of match >> with >> potentially questionable results. > > I believe the idea is that it isn't for caches to override or police > the origin server's policy, but to provide a generic caching mechanism > that supports negotiation, and let the origin server implement the > negotiation policy however it likes. > > That is much more extensible to the future, and works with all request > headers, including types of negotation which aren't mentioned in any > spec. > > I don't see any advantage in making the cache "smarter" than this, and > several disadvantages. > > For example, imaging a server which responds with this text > as a diagnostic service: > > HTTP/1.1 200 UK > Vary: Content-Language > Content-Type: text/html > Etag: 5346593659365 > > <html><head></head><body> > > Thank you for your request.<br> > Your request provided the following language list: "en-nz, fr". > > </body></html> > > I think that's a legitimate cacheable response, and one where you > would want the origin server to be consulted when a request comes > along with Content-Language in a different order. > > -- Jamie > -- Mark Nottingham http://www.mnot.net/
Received on Monday, 8 June 2009 00:34:03 UTC