- From: Mark Nottingham <mnot@mnot.net>
- Date: Fri, 30 Nov 2018 11:39:33 +1100
- To: Bruce Adams <tortoise_74@yahoo.co.uk>
- Cc: RFC Errata System <rfc-editor@rfc-editor.org>, Roy Fielding <fielding@gbiv.com>, "Julian F. Reschke" <julian.reschke@greenbytes.de>, ben@nostrum.com, Alexey Melnikov <aamelnikov@fastmail.fm>, Adam Roach <adam@nostrum.com>, Patrick McManus <patrick.ducksong@gmail.com>, tpauly@apple.com, ietf-http-wg@w3.org
Hi Bruce! See: https://httpwg.org/specs/rfc7234.html#cache.control.extensions Along with this text in sections 3 and 4: "Note that any of the requirements listed above can be overridden by a cache-control extension; see Section 5.2.3." Cheers, > On 30 Nov 2018, at 1:21 am, Bruce Adams <tortoise_74@yahoo.co.uk> wrote: > > Hi, > > That makes sense. I didn't realise extension could override, particularly in the case of a "MUST". > For my own education where would I find this policy? > > If I interpret this correctly I can for a ReST service return a stale document and > "warning 111 response is stale" provided my response also includes "stale-while-revalidate" from rfc5861. > > Regards, > > Bruec. > > On Tuesday, November 27, 2018, 10:50:57 PM GMT, Mark Nottingham <mnot@mnot.net> wrote: > > > REJECT. Extensions are explicitly allowed to override requirements, and making this a SHOULD would be too confusing (as many would read it as "optional"). > > > > > On 27 Nov 2018, at 10:37 pm, RFC Errata System <rfc-editor@rfc-editor.org> wrote: > > > > The following errata report has been submitted for RFC7234, > > "Hypertext Transfer Protocol (HTTP/1.1): Caching". > > > > -------------------------------------- > > You may review the report below and at: > > http://www.rfc-editor.org/errata/eid5564 > > > > -------------------------------------- > > Type: Technical > > Reported by: Bruce Adams <tortoise_74@yahoo.co.uk> > > > > Section: 4.2.4 > > > > Original Text > > ------------- > > A cache MUST NOT send stale responses unless it is disconnected > > (i.e., it cannot contact the origin server or otherwise find a > > forward path) or doing so is explicitly allowed (e.g., by the > > max-stale request directive; see Section 5.2.1). > > > > Corrected Text > > -------------- > > A cache SHOULD NOT send stale responses unless it is disconnected > > (i.e., it cannot contact the origin server or otherwise find a > > forward path) or doing so is explicitly allowed (e.g., by the > > max-stale request directive; see Section 5.2.1). > > > > A cache MAY send stale responses if a cache-control extension for > > stale content such as "stale-while-revalidate" is used > > (see RFC5861). > > > > Notes > > ----- > > The original text seems to conflict with https://tools.ietf.org/html/rfc5861#section-3 > > > > 3. The stale-while-revalidate Cache-Control Extension > > > > When present in an HTTP response, the stale-while-revalidate Cache- > > Control extension indicates that caches MAY serve the response in > > which it appears after it becomes stale, up to the indicated number > > of seconds. > > > > stale-while-revalidate = "stale-while-revalidate" "=" delta-seconds > > > > If a cached response is served stale due to the presence of this > > extension, the cache SHOULD attempt to revalidate it while still > > serving stale responses (i.e., without blocking). > > > > See also https://stackoverflow.com/questions/53324538/rest-low-latency-how-should-i-reply-to-a-get-while-an-upload-is-pending > > > > Instructions: > > ------------- > > This erratum is currently posted as "Reported". If necessary, please > > use "Reply All" to discuss whether it should be verified or > > rejected. When a decision is reached, the verifying party > > can log in to change the status and edit the report, if necessary. > > > > -------------------------------------- > > RFC7234 (draft-ietf-httpbis-p6-cache-26) > > -------------------------------------- > > Title : Hypertext Transfer Protocol (HTTP/1.1): Caching > > Publication Date : June 2014 > > Author(s) : R. Fielding, Ed., M. Nottingham, Ed., J. Reschke, Ed. > > Category : PROPOSED STANDARD > > Source : Hypertext Transfer Protocol Bis APP > > Area : Applications > > Stream : IETF > > Verifying Party : IESG > > > -- > Mark Nottingham https://www.mnot.net/ > -- Mark Nottingham https://www.mnot.net/
Received on Friday, 30 November 2018 00:40:18 UTC