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Re: NEW ISSUE: weak validator: definition inconsistent

From: Werner Baumann <werner.baumann@onlinehome.de>
Date: Thu, 03 Jan 2008 21:28:43 +0100
Message-ID: <477D457B.7090608@onlinehome.de>
To: Larry Masinter <LMM@acm.org>
CC: ietf-http-wg@w3.org


Larry Masinter wrote:
> I don't think it is a good idea to remove the term, but it would be better
> to define it more carefully, perhaps to remove the notion of "semantic
> equivalence" and replace it with "good enough, from the server's point of
> view". That is, a server is free to report a "match" on a weak validator if
> the server thinks an entity previously served with that validator is "good
> enough", from the server's point of view. Whether that's semantically
> equivalent doesn't need to come into the picture, except as an example of
> one reason why, even if something has changed, you might be content to let
> the client use old content.
> 
I would agree with this definition of weak validators (including weak 
etags). In this case restriction of any weak validators to conditional 
full body GET-requests makes sense.

As all that stuff about semantic equivalence raises expectations, that a 
weak etag can be used to proof semantic equivalence, what does not work, 
most of it should be removed (except maybe as one among very different 
examples, as you suggest).

As dealing with semantic equivalence implies some common understanding 
of it by server and clients, it is probably beyond the scope of the 
HTTP-protocol. But I have no idea whether there are already 
implementations that will with this.

Cheers
Werner
Received on Thursday, 3 January 2008 20:29:05 GMT

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