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Re: qvalue *

From: Frank Ellermann <nobody@xyzzy.claranet.de>
Date: Tue, 5 Aug 2008 00:50:17 +0200
To: ietf-http-wg@w3.org
Message-ID: <g78118$427$1@ger.gmane.org>

Henrik Nordstrom wrote:

>> All match *;q=0.7.  Toss a coin ?  Take always the last,
>> i.e. for utf-8;q=0.7,*;q=0.7 take the * and toss a coin ?

> Toss a coin.

Okay, that answers that:  The utf-8;q=0.7 is redundant, but
actually harmless.  Maybe Julian's or my UAs shouldn't do
it, as it could cause harm for discussions on this list ;-)

 [* qvalue not the smallest non-zero qvalue]
> I don't see it stange. It's a negative prose. "I really
> prefer anything else than...". Useful as an optimization
> when you have problems with something specific
[...]

> "bocu-1;q=0.5;Koi8-r,*;q=0.7"

> * prefer Koi8-r.
> * use bocu-1 only if no other is available

Oh, you found a plausible meaning for non-zero and smaller
than *.  That is good, so far I assumed that this _must_ be
erroneous.

> Or using Accept to illustrate the need for negative proses
> better:

> "*/*; q=0.5, movie/mpeg;q=0, image/jpeg, text/*"

> for an application that understands most content, have
> some preferences on preferred content, but knows it can
> not decode mpeg content (patent issues).

Yes, I got this idea for zero, but not for non-zero.  Maybe
a better example is application/pdf:

..., text/*, */*;q=0.2, application/pdf;q=0.1

"If all else fails I'm willing to try my luck with PDF 
 before giving up".

> no real room for confusion. You just have to keep in mind
> that the specifications is written from a server 
> perspective here starting out with all available variants
> of the resource and finding the qvalue for each of them
> and then filtering and sorting the result..

Well, it did confuse me.  Now that you've shown me a simple
example it's perfectly clear.  But maybe it was not only me,
others apparently also didn't exactly know what the purpose
of a wildcard with a "medium" <qvalue> is.

So that IMO needs a plausible example, explaining what you
wrote above (not the mpeg;q=0 case, that's IMO too simple).

 Frank
Received on Monday, 4 August 2008 22:49:58 GMT

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