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RE: Label header vs PROPFIND depth 1

From: Julian Reschke <julian.reschke@greenbytes.de>
Date: Mon, 22 Apr 2002 20:39:06 +0200
To: <tim@ellison.name>, "'Deltav WG'" <ietf-dav-versioning@w3.org>
Message-ID: <JIEGINCHMLABHJBIGKBCKEEGEHAA.julian.reschke@greenbytes.de>
> > From: ietf-dav-versioning-request@w3.org
> > [mailto:ietf-dav-versioning-request@w3.org]On Behalf Of Clemm, Geoff
> > Sent: 22 April 2002 19:02
> > To: 'Deltav WG'
> > Subject: RE: Label header vs PROPFIND depth 1
> >
> >
> >    From: Lisa Dusseault [mailto:ldusseault@xythos.com]
> >
> >    Geoff said:
> >    >    PROPFIND /a
> >    >    Depth: 1
> >    >    Label: labeltest
> >    > Assuming /a is not version-controlled, then the effect of the Label
> >    > header is undefined, so your implementation could just ignore the
> >    > Label header and return the properties of /a, or it could indicate
> >    > that it is an error for /a.
> >    >
> >    > Since /a/b is version-controlled, the effect is defined by section
> >    > 8.6, and you would return the properties of the version labeled
> >    > "labeltest".
> >
> >    This is interesting -- I thought that the RFC said that the label
> >    header must be ignored if the resource is not version-controlled.
> >    Thus, it would be *wrong* to return an error for /a.
> >
> > Lisa is of course correct.  Section 8.3 covers this case.
> > So yes, it must be ignored for a non-version-controlled resource,
> > so it would be wrong to return an error for /a.
>
> Right, so imagine what kind of answer you would get back in the
> multistatus -- some would be from the unversioned resource propfinds and
> some from version propfinds, and you wouldn't know which were versioned
> (without explictly looking for a live property to distinguishe
> them), _and_

Yes -- I think this is what RFC3253 says.

> it would contravene the 2518 depth result requirement I mentioned earlier.

I don't think so.

> a version-controlled resource for which the label doesn't exist?
> >
> > See section 8.6, the DAV:must-select-version-in-history precondition.
> > It is an error if you request a label that does not exist on a
> given VCR.

So assume we have /a (collection, not-versioned), /a/b (not-versioned), /a/c
(versioned, having a version labeled "x") and /a/d (versioned, without that
label).

I think we all agree that

GET /a/c
Label: x

Should return the content of the version selected by the label x (including
a vary header and probably a content-location header).

GET /a/d
Label: x

will return 403 or 409 with an error element (precondition
DAV:must-select-version-in-history failed).

GET /a/b
Label: x

will just return b's content, and the vary header when present will NOT
include "Label".

Similarily, similar results will be returned for a PROPFIND/depth 0 on these
resources. Note that the response element will be "/a/c" in the first case,
even if the properties of a version with a different URI were reported.

Finally, we have PROPFIND/depth 1 on /a:

- as /a isn't version-controlled, the label header is ignored for *this*
resource

- Geoff and I claim that it *should* apply to the members then, so we'd get:

<multistatus xmlns="DAV:">

  <response>
    <href>/a</href>
    <propstat>
      <prop>...</prop>
      <status>HTTP/1.1 200 OK</status>
    </propstat>
  <response>

  <response>
    <href>/a/b</href>
    <propstat>
      <prop>properties of resource /a/b</prop>
      <status>HTTP/1.1 200 OK</status>
    </propstat>
  <response>

  <response>
    <href>/a/c</href>
    <propstat>
      <prop>properties of selected version</prop>
      <status>HTTP/1.1 200 OK</status>
    </propstat>
  <response>

  <response>
    <href>/a/d</href>
    <status>HTTP/1.1 409 Conflict</status>

<responsedescription><error>must-select-version-in-history/></error></respon
sedescription>
  <response>

</multistatus>
Received on Monday, 22 April 2002 14:40:19 GMT

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