RE: New Version Notification for draft-nottingham-http-availability-hints-00.txt

Broadly, I like it.  I think Variants had a lot of potential to improve caching and am disappointed it hasn't made more progress; this might be an easier way to approach the problem.

It seems like you're moving in a direction where:

  *   These headers are always lists
  *   Equivalence classes MAY be indicated by including a sublist as a list element, for axes where it's possible for different values to produce identical responses
  *   One list element MAY be indicated as default, for axes where a default makes sense and isn't already implicit

It'd be nice to be able to define this more generally, but you may be on the right track that many of the Accept-* headers have enough individual quirks that they'll all have to be separately defined.

Minor nits:

  *   I'm unenthused by "Avail" as a prefix here, purely because it's an actual word that isn't actually what you mean.  Do we really need to save those four characters?
  *   5.3, Avail-Format => Avail-Language

From: Mark Nottingham <>
Sent: Saturday, March 11, 2023 9:49 PM
To: HTTP Working Group <>
Subject: Fwd: New Version Notification for draft-nottingham-http-availability-hints-00.txt

FYI - this is a draft that I think is suitable for replacing the Variants specification. It conveys roughly the same information, but in a much more simple and intuitive way. Many parts are just sketched out to be filled in later, but it should be possible to get the general idea being proposed.

Thoughts? If there's interest, I might ask for five minutes in Yokohama to talk about adoption.


Begin forwarded message:

Subject: New Version Notification for draft-nottingham-http-availability-hints-00.txt
Date: 12 March 2023 at 1:47:09 pm AEDT
To: "Mark Nottingham" <<>>

A new version of I-D, draft-nottingham-http-availability-hints-00.txt
has been successfully submitted by Mark Nottingham and posted to the
IETF repository.

Name:                  draft-nottingham-http-availability-hints
Revision:              00
Title:                     HTTP Availability Hints
Document date:               2023-03-11
Group:                  Individual Submission
Pages:                  10

  This specification defines availability hints, a new class of HTTP
  responses headers that augment the information in the Vary header

The IETF Secretariat

Mark Nottingham

Received on Monday, 13 March 2023 18:34:25 UTC