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RE: II.6, non-reusable version URLs (was: comments on deltav-10.5 from Yaron Goland, Act Two)

From: Clemm, Geoff <gclemm@rational.com>
Date: Fri, 15 Dec 2000 20:53:58 -0500
Message-ID: <3906C56A7BD1F54593344C05BD1374B101685C9E@SUS-MA1IT01>
To: ietf-dav-versioning@w3.org
Lisa asked for a use case that
motivated requiring that version URL's not be
re-used (she suggests having a client that cares
just use the etag).  I believe that Boris has
provided a reasonable use case here ... do people
agree?

Note that Lisa's objection was not based on
implementation difficulty, but rather lack of
motivation for the requirement.

Another objection was that this requirement
would cause the version URL's to become longer
and more obscure.  I personally would be unlikely
to "type in" a version URL, but instead would just
be "clicking" on one (as in Boris' example below),
so the length/obscurity of the version URL matters
much less to me than its reliability.

Minimally we will say that a version URL SHOULD be
unique, but when I wear my client-writer's hat, I
find SHOULD's relatively worthless, and only care
about MUST's.

What do other folks think?

Cheers,
Geoff

-----Original Message-----
From: Boris Bokowski/OTT/OTI [mailto:Boris_Bokowski@oti.com]
Sent: Wednesday, December 13, 2000 11:51 AM
To: ietf-dav-versioning@w3.org
Subject: RE: II.6, non-reusable version URLs (was: comments on
deltav-10.5 from Yaron Goland, Act Two)


> I'd never recommend to any client to stop using ETags for this purpose!
> Sounds dangerous.  The client always ought to rely on the ETag to see
> if things have changed.  Require clients to use ETag for what it was
> designed, and further, require clients to be able to deal with re-use
> of version URLs.  It's good medicine.
>
> Now, my second line of defense for this is usability.  Assuming somebody
> will want to put version links as URLs in web pages, or in emails, then
> it would be more usable to at least be able to construct short, possibly
> meaningful version URLs.  The use of a GUID will preclude this.
> 
> FWIW, here's what a Xythos Version URL for a real file looks like:
>
http://www.sharemation.com/~milele/public/advanced-status-reporting.htm?vers
ion=1

To me, this looks like a good example where in practice, a URL is all you 
can send to me. It's just not practical to send me the ETag as well, 
because there is no easy way for me to check it. I think I would prefer 
clicking on a URL such as
http://www.sharemation.com/~milele/public/advanced-status-reporting.htm/0074
1ab6a2c400141e860000c0a80cc2
or
http://www.sharemation.com/~milele/public/advanced-status-reporting.htm?vers
ion=1&etag=1fe4-69-39e7056c
over checking the ETag myself.

With reusable version URLs, users would need to know about ETags. Example: 
If you accidentally deleted advanced-status-reporting.htm and then
re-created it, a URL which just 
says ?version=1 would link to the latest version of that document instead 
of the first version.

-Boris.
Received on Friday, 15 December 2000 20:54:40 GMT

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