29 Jul 2012 19:57
Re: Straw-man for our next charter
what are the use cases and requirements for such gateways?
A general purpose omni-site 2.0->1.1 gateway might need to do sniffing of sites not known to have correct content-type headers, but 1.1->2.0 gateways shouldn't need to change content-type .... sniffing leaves correctly labeled content intact, of course. :)
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A general purpose omni-site 2.0->1.1 gateway might need to do sniffing of sites not known to have correct content-type headers, but 1.1->2.0 gateways shouldn't need to change content-type .... sniffing leaves correctly labeled content intact, of course. :)
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-----Original message-----
From: Adam Barth <w3c <at> adambarth.com>
To: Larry Masinter <masinter <at> adobe.com>
Cc: "ietf-http-wg <at> w3.org" <ietf-http-wg <at> w3.org>
Sent: Sun, Jul 29, 2012 00:53:44 GMT+00:00
Subject: Re: Straw-man for our next charter
From the charter:---8<---Changes to the existing semantics of HTTP are out of scope in order to
preserve the meaning of messages that might cross a 1.1 --> 2.0 --> 1.1
request chain.--->8---Changing how user agents interpret the Content-Type header would change the semantics of HTTP and are therefore out of scope for HTTP/2.0 according to our current charter.AdamOn Sat, Jul 28, 2012 at 8:01 AM, Larry Masinter <masinter <at> adobe.com> wrote:The sniffing I was in particular hoping to stop is content-type sniffing.
http://tools.ietf.org/html/draft-ietf-websec-mime-sniff-03
" Many web servers supply incorrect Content-Type header fields with
their HTTP responses. In order to be compatible with these servers,
user agents consider the content of HTTP responses as well as the
Content-Type header fields when determining the effective media type
of the response."
If browsers suddenly stopped sniffing HTTP/1.1 content, it would break existing web sites, so of course the browser makers are reluctant to do that.
However, if it was a requirement to supply a _correct_ content-type header for HTTP/2.0, and no HTTP/2.0 client sniffed, then sites upgrading to HTTP/2.0 would fix their content-type sending (because when they were deploying HTTP/2.0 they would have to in order to get any browser to work with them.)
Basically, sniffing is a wart which backward compatibility keeps in place. Introducing a new version is a unique opportunity to remove it.
The improved performance would come from having to look at the content to determine before routing to the appropriate processor.
Larry
Sent: Friday, July 27, 2012 11:53 PM
To: ietf-http-wg <at> w3.org
Subject: Re: Straw-man for our next charter
On 28/07/2012 6:39 p.m., Larry Masinter wrote:
> re changes to semantics: consider the possibility of eliminating
> "sniffing" in HTTP/2.0. If sniffing is justified for compatibility
> with deployed servers, could we eliminate sniffing for 2.0 sites?
>
> It would improve reliability, security, and even performance. Yes,
> popular browsers would have to agree not to sniff sites running 2.0,
> so that sites wanting 2:0 benefits will fix their configuration.
>
> Likely there are many other warts that can be removed if there is a
> version upgrade.
Which of the several meanings of "sniffing" are you talking about exactly?
AYJ
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