RE: Which status codes are cacheable?

• From: Brian Smith <brian@briansmith.org>
• Date: Thu, 15 Oct 2009 14:17:18 -0500
• To: "'Mark Nottingham'" <mnot@mnot.net>
• Cc: "'HTTP Working Group'" <ietf-http-wg@w3.org>
• Message-ID: <000601ca4dcc$1fbc6d30$5f354790$@org>

Mark Nottingham wrote:
> My reading is that while it's not crystal-clear, 2616 doesn't
> predicate whether a response can be stored upon its status code,
> because
>    a) no where is this specified with a MUST or SHOULD-level
> requirement, and
>    b) caches are explicitly allowed (with a MAY) to store any
> successful (in the sense of "it's complete") response, and
>    c) cache-control headers are explicitly allowed to relax semantic
> transparancy for any response -- including those with unknown status
> codes.

This is not true. See RFC2616, Section 6.1.1:

  However, applications MUST understand the class of any status code,
  as indicated by the first digit, and treat any unrecognized
  response as being equivalent to the x00 status code of that class,
  with the exception that an unrecognized response MUST NOT be cached.

This same restriction is also in Part 2, Section 4 of the latest draft,
RFC2068 Section 6.1.1, and RFC1945 Section 6.1.1.

Regards,
Brian

Received on Thursday, 15 October 2009 19:17:52 UTC