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Re: PROPOSAL: Weak Validator definition [i101]

From: Robert Siemer <Robert.Siemer-httpwg@backsla.sh>
Date: Sun, 16 Mar 2008 16:23:35 +0100
To: Werner Baumann <werner.baumann@onlinehome.de>
Cc: ietf-http-wg@w3.org
Message-ID: <20080316152335.GA32440@polar.elf12.net>

On Sat, Mar 15, 2008 at 09:55:30AM +0100, Werner Baumann wrote:
> Henrik Nordstrom wrote:
> >On Fri, 2008-03-14 at 21:35 +0100, Werner Baumann wrote:
> >>The spec is self-contradictory and the parts that state "semantic 
> >>equivalence" should be removed.
> >
> >Agreed. All definitons of weak should be based on "SHOULD change when
> >the entity changes in a semantically significant way".
> >
> >Regards
> >Henrik
> >
> Using SHOULD only would turn a strong self-contradiction into a weak 
> self-contradiction.
> I still suggest to remove "semantic" from all validator related stuff 
> and instead use wording as proposed by Mark Nottingham: "good enough,
> from the server's point of view".
> I originally raised this issue, because I believed in weak etags 
> guaranteeing something like "semantic equivalence" and I was 
> disappointed when it turned out to be an illusion. My experience is 
> restricted to Apache and IIS. Weak etags created by this two servers are 
> not related to semantics in any way. They are weak only because of the 
> limited resolution of Last-Modified-Date.
> Are there any implementations of weak validators, that refer to semantic 
> equivalence?

There are. At least some of my CGI scripts use them. - I would not 
discard that many other CGIs do the same.

To see no useful weak etag implementations within the static file 
serving code among common servers does not surprise me at all. - How 
should they know about semantic equivalence?

I still don't know why this mecanism has to be an illusion. 

Received on Sunday, 16 March 2008 15:23:03 UTC

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