Subject: I-D Action: draft-ietf-httpbis-header-structure-01.txt

From: [email-masked]
Date: Tue, 25 Apr 2017 01:46:55 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Hypertext Transfer Protocol of the IETF.

        Title           : HTTP Header Common Structure
        Author          : Poul-Henning Kamp
	Filename        : draft-ietf-httpbis-header-structure-01.txt
	Pages           : 16
	Date            : 2017-04-25

Abstract:
   An abstract data model for HTTP headers, "Common Structure", and a
   HTTP/1 serialization of it, generalized from current HTTP headers.

Note to Readers

   Discussion of this draft takes place on the HTTP working group
   mailing list ([email-masked]), which is archived at
   https://lists.w3.org/Archives/Public/ietf-http-wg/ .

   Working Group information can be found at http://httpwg.github.io/ ;
   source code and issues list for this draft can be found at
   https://github.com/httpwg/http-extensions/labels/header-structure .

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-httpbis-header-structure/

There are also htmlized versions available at:
https://tools.ietf.org/html/draft-ietf-httpbis-header-structure-01
https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-header-structure-01

A diff from the previous version is available at:
https://www.ietf.org/rfcdiff?url2=draft-ietf-httpbis-header-structure-01

Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org.

Internet-Drafts are also available by anonymous FTP at:
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From: Amos Jeffries <[email-masked]>
Date: Wed, 26 Apr 2017 09:24:26 +1200

Reading section 7.1 I am wondering if this is significant enough to use 
HTTP/1.2 version number for 1.x agents as the signal that the sender can 
receive any header in self-describing Common Structure.

What would be the limiting factors of minting a new minor version in 1.x ?
HTTP/2 is better placed with negotiable SETTINGs so it is not an issue 
there.

Amos

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From: "Poul-Henning Kamp" <[email-masked]>
Date: Tue, 25 Apr 2017 21:43:44 +0000

--------
In message <[email-masked]>, Amos Jeffries 

>receive any header in self-describing Common Structure.

That's an interesting question...

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
[email-masked]         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

---

From: Matthew Kerwin <[email-masked]>
Date: Wed, 26 Apr 2017 09:16:43 +1000

> That's an interesting question...
​Very interesting.  The request line is a hop-by-hop message, right?  So it
couldn't be used as a signal for end-to-end headers.

How many middleboxen out there are likely to inspect the request line only
as far as 'HTTP_VERSION > 1.0' and then barf if one of their response
headers looks weird?  Although I suppose the answer is not that different
from: how many will forward X-Accept-Fancy-Headers blindly and then
barf...  Pity there was no strong hop-by-hop vs end-to-end flag on headers.

Cheers
-- 
  Matthew Kerwin
  http://matthew.kerwin.net.au/

---

From: Amos Jeffries <[email-masked]>
Date: Thu, 27 Apr 2017 00:04:50 +1200

On 26/04/17 11:16, Matthew Kerwin wrote:
>
>
> On 26 April 2017 at 07:43, Poul-Henning Kamp <[email-masked] 
> <mailto:[email-masked]>> wrote:
>
>     --------
>     In message <[email-masked]
>     <mailto:[email-masked]>>, Amos
>     Jeffries
>     writes:
>
> ​Very interesting.  The request line is a hop-by-hop message, right?  
> So it couldn't be used as a signal for end-to-end headers.

I'm thinking that headers affected by this signal would have a 'legacy' 
format - for example Date. So this use-case would be hop-by-hop 
opportunistic performance optimization. Any agent using it would need to 
be able to map.

> How many middleboxen out there are likely to inspect the request line 
> only as far as 'HTTP_VERSION > 1.0' and then barf if one of their 
> response headers looks weird?  Although I suppose the answer is not 
> that different from: how many will forward X-Accept-Fancy-Headers 
> blindly and then barf... Pity there was no strong hop-by-hop vs 
> end-to-end flag on headers.
>
> Cheers
> -- 
>   Matthew Kerwin