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Re: Why Microsoft's authoritative=true won't work and is a bad idea

From: Henrik Nordstrom <henrik@henriknordstrom.net>
Date: Mon, 07 Jul 2008 15:19:38 +0200
To: Julian Reschke <julian.reschke@gmx.de>
Cc: Ian Hickson <ian@hixie.ch>, Sam Ruby <rubys@us.ibm.com>, HTTP Working Group <ietf-http-wg@w3.org>, "public-html@w3.org" <public-html@w3.org>
Message-Id: <1215436778.20418.79.camel@henriknordstrom.net>
[sorry for the missing red thread in this message, please read it in
full before responding]

On mån, 2008-07-07 at 09:33 +0200, Julian Reschke wrote:

> The IETF HTTPbis working group has no mandate to do so. Thus it would 
> need to be rechartered, or a new WG would have to start.

And from a protool specification and common sense point of view it would
be the wrong thing to officially allow sniffing even when the
content-type is clearly specified.

HTTP already specifies when sniffing is allowed or not. Major browser
vendors have over time and by intent choosen to ignore this part of the
specifications, and now their ignorance is coming back and biting them
and their users. Does this mean that specifications should change to
allow for these bugs to grow into a standard feature encouraging

It also seems that some noticeable players have lost faith, thinking
that things won't improve over time and things will stay as bad or worse
over time. An attitude I find a bit disturbing when working with
specifications as it means nothing can be changed or fixed other than
documenting how broken the current implementations is today, ending in
the rationale that "UTF7 content sniffing is implemented by some, so it
must be supported by everyone even if completely stupid and current
specifications we all agreed to implement years ago says you MUST NOT".

Yee, it do take some years of effort before any result in these areas at
all is seen, but it's certainly not impossible. I have been fighting
some of these wars, and some hours per year over some years nagging the
right people about something which bothers you can make a difference.

Yes, in the end there will be some old minor sites no longer working
well with newer browsers if sniffing is deprecated. But there will also
be existing major sites working better, being able to use content types
as intended instead of having to find ways around the browsers guessing

HTTP intentionally does not specify how sniffing is to be implemented or
evaluated. That's a client implementation detail as far as HTTP is
concerned, and extra feature to be used when nothing else is known about
the content.

> > How is that possible?
> Using Microsoft's proposal or by using a separate header, for instance.

If it wasn't for the Apache answer that if such extension gets commonly
available then it will be set by default by Apache, and things would go
back to square -1 by the reasoning applied earlier, with even more bits
on the wire that nobody want's to trust because server admins is by
definition not trustworthy to be willing to make their servers conform
with requirements or in general completely ignorant if their content
breaks for large parts of their user base because of this.

My concern about the proposal or added header is the reverse. Yes, it
will enable servers to tell next generation of clients to trust them,
but on the downside it will give more slack to the proponents which
thinks sniffing is the solution to how to deal with mislabelled content.
It's not a real solution to the problem, in fact it encourages that bug
to grow even bigger, just adding a workaround to be able to ask that bug
to go and hide for a while.

> Well, the biggest vendor just put a proposal on the table that would 
> make it possible to disable sniffing altogether.
> Maybe it would make sense to consider it seriously, instead of 
> immediately stating "won't work"?

It will work, at least temporarily until there is again sufficient
amount of mislabelled content.

The only real long term solution I see to this problem is for major
browser vendors to gradually stop sniffing content even without this
extension. Add "serer trust" levels similar to how cookies
black/whitelisting is managed, enabling the browsers to learn (by user
experience) which sites label their content proerly and which don't. A
good start on this track is to add a visible indication when mislabelled
content is detected, enabling users to see when there is something wrong
without "destroying the web".


Received on Monday, 7 July 2008 13:21:38 UTC

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