- From: Julian F. Reschke <julian.reschke@greenbytes.de>
- Date: Sun, 9 Sep 2001 19:50:24 +0200
- To: "Julian F. Reschke" <julian.reschke@greenbytes.de>, <ietf-dav-versioning@w3.org>
- Message-ID: <JIEGINCHMLABHJBIGKBCCEJGDAAA.julian.reschke@greenbytes.de>
Attached is an ID-formatted version of my proposal (below in text format,
attached as RFC2629-XML).
--
Network Working Group J. Reschke
Internet-Draft greenbytes
Expires: March 10, 2002 September 9, 2001
Computing the CHECKIN URI in WebDAV versioning
draft-reschke-deltav-computecheckinuri-00
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on March 10, 2002.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
In many cases, a versioning-aware client might want to
display/include the URI of the version it's editing while it's being
edited. For instance, an editor might include this as meta
information, or the author of a document might want to know the URI
of the version before it's checked in. A well-known example is the
W3C way of referring to document versions in recommendations: it
contains references to "the current version", to "this version" and
to the "previous version". Something like this is currently
impossible with the current draft version of WebDAV deltaV [deltaV],
as the version URI is determined at the time of CHECKIN.
Distribution of this document is unlimited. Please send comments to
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the WebDAV versioning (delta-V) working group at ietf-dav-
versioning@w3.org[1], which may be joined by sending a message with
subject "subscribe" to ietf-dav-versioning-request@w3.org[2].
Discussions of the delta-V working group are archived at URL:
http://lists.w3.org/Archives/Public/ietf-dav-versioning/.
Table of Contents
1. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Changes for CHECKOUT method (when applied to a
version-controlled resource) . . . . . . . . . . . . . . . . . 5
3.1 Example for successful CHECKOUT with computed-checkin-URI . . 5
3.2 Example for successful CHECKOUT without computed-checkin-URI . 6
4. Changes for CHECKIN method (when applied to a
version-controlled resource) . . . . . . . . . . . . . . . . . 7
4.1 Example for successful CHECKIN with computed-checkin-URI . . . 7
4.2 Example for failed CHECKIN with computed-checkin-URI . . . . . 8
5. Compatibility Considerations . . . . . . . . . . . . . . . . . 9
6. Internationalization Considerations . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
8. Copyright . . . . . . . . . . . . . . . . . . . . . . . . . . 12
9. Intellectual Property . . . . . . . . . . . . . . . . . . . . 13
References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Author's Address . . . . . . . . . . . . . . . . . . . . . . . 14
Full Copyright Statement . . . . . . . . . . . . . . . . . . . 15
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1. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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2. Introduction
In many cases, a versioning-aware client might want to
display/include the URI of the version it's editing while it's being
edited. For instance, an editor might include this as meta
information, or the author of a document might want to know the URI
of the version before it's checked in. A well-known example is the
W3C way of referring to document versions in recommendations: it
contains references to "the current version", to "this version" and
to the "previous version". Something like this is currently
impossible with the current draft version of WebDAV deltaV [deltaV],
as the version URI is determined at the time of CHECKIN.
This specification builds on the infrastructure provided by the
WebDAV Versioning Protocol, adding support for servers willing to
compute an "expected CHECKIN URI" upon CHECKOUT, and using this URI
at time of CHECKIN.
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3. Changes for CHECKOUT method (when applied to a version-controlled
resource)
A client may ask for an "expected CHECKIN URI" upon CHECKOUT. This
is done by placing DAV:compute-expected-checkin-URI as top-level
element into the request body. The server is free to either ignore
the request, or to return it's best guess about what the URI for a
version resource created upon CHECKIN would be.
The client can detect the "expected CHECKIN URI" by parsing the
response body for a top-level element called DAV:expected-checkin-
URI.
3.1 Example for successful CHECKOUT with computed-checkin-URI
>>Request
CHECKOUT /foo.html HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
<D:checkout xmlns:D="DAV:">
<D:compute-expected-version-URI />
</D:checkout>
>>Response
HTTP/1.1 200 OK
Cache-Control: no-cache
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
<D:checkout-response xmlns:D="DAV:">
<D:expected-version-URI>http://repo.webdav.org/his/23/ver/32</D:expected-ver
sion-URI>
</D:checkout-response>
In this example, the server was able to compute the "expected CHECKIN
URI" and returned it in the DAV:expected-version-URI element.
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3.2 Example for successful CHECKOUT without computed-checkin-URI
>>Request
CHECKOUT /foo.html HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
<D:checkout xmlns:D="DAV:">
<D:compute-expected-version-URI />
</D:checkout>
>>Response
HTTP/1.1 200 OK
Cache-Control: no-cache
In this case, no response body was returned, and thus no "expected
CHECKIN URI" is available. Simarily, the server may also return
>>Response
HTTP/1.1 200 OK
Cache-Control: no-cache
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
<D:checkout-response xmlns:D="DAV:">
...other content...
</D:checkout-response>
where a response body is available, but it doesn't contain the
DAV:expected-checkin-URI element.
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4. Changes for CHECKIN method (when applied to a version-controlled
resource)
A client may submit the "expected CHECKIN URI" (obtained during
CHECKOUT) upon a CHECKIN by placing it into a top-level DAV:expected-
checkin-URI element in the request body. A server may
o simply ignore the presence of this information or
o use the information and try to checkin the resource using the
"expected checkin URI" as location for the version resource. A
failure to create a version resource at the "expected checkin URI"
MUST cause the operation to fail with a status code of 403
(forbidden) and a response body containing the top-level element
DAV:cannot-assign-expected-version-URI. In addition, a server MAY
return a new "expected checkin URI" in it's response body.
4.1 Example for successful CHECKIN with computed-checkin-URI
>>Request
CHECKIN /foo.html HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
<D:checkin xmlns:D="DAV:">
<D:expected-version-URI>http://repo.webdav.org/his/23/ver/32</D:expected-ver
sion-URI>
</D:checkin>
>>Response
HTTP/1.1 201 Created
Location: http://repo.webdav.org/his/23/ver/32
Cache-Control: no-cache
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4.2 Example for failed CHECKIN with computed-checkin-URI
>>Request
CHECKIN /foo.html HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
<D:checkin xmlns:D="DAV:">
<D:expected-version-URI>http://repo.webdav.org/his/23/ver/32</D:expected-ver
sion-URI>
</D:checkin>
>>Response
HTTP/1.1 403 Forbidden
Cache-Control: no-cache
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
<D:checkin-response xmlns:D="DAV:">
<D:cannot-assign-expected-version-URI />
<D:expected-version-URI>http://repo.webdav.org/his/23/ver/33</D:expected-ver
sion-URI>
</D:checkin-response>
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5. Compatibility Considerations
This specification does introduce new protocol elements for the
request and response bodies for CHECKIN and CHECKOUT.
Clients not aware of this specification will never submit the new
protocol elements in a request and therefore never will see the new
response elements.
Servers not aware of this specification will ignore the additional
two request body elements which is legal behaviour according to this
protocol (indicating that the protocol extension is not available).
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6. Internationalization Considerations
This proposal builds on [deltaV], and inherits its
internationalizability.
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7. IANA Considerations
This proposal does not introduce any new IANA considerations, since
it does not specify any new namespaces (in the general sense), but
merely uses existing ones.
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8. Copyright
To be supplied by the RFC Editor.
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9. Intellectual Property
To be supplied by the RFC Editor.
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References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2518] Goland, Y., Whitehead, E., Faizi, A., Carter, S. and D.
Jensen, "HTTP Extensions for Distributed Authoring --
WEBDAV", RFC 2518, February 1999.
[deltaV] Clemm, G., Amsden, J., Ellison, T., Kaler, C. and J.
Whitehead, "Versioning Extensions to WebDAV", ID draft-
ietf-deltav-versioning-17, August 2001,
<http://www.webdav.org/deltav/protocol/draft-ietf-deltav-
versioning-17.htm>.
[1] <mailto:ietf-dav-versioning@w3.org>
[2] <mailto:ietf-dav-versioning-request@w3.org?subject=subscribe>
Author's Address
Julian F. Reschke
greenbytes GmbH
Salzmannstrasse 152
Muenster, NW 48159
Germany
EMail: julian.reschke@greenbytes.de
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Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
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the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
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English.
The limited permissions granted above are perpetual and will not be
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Reschke Expires March 10, 2002 [Page 15]
> -----Original Message-----
> From: ietf-dav-versioning-request@w3.org
> [mailto:ietf-dav-versioning-request@w3.org]On Behalf Of Julian F.
> Reschke
> Sent: Friday, September 07, 2001 9:23 PM
> To: ietf-dav-versioning@w3.org
> Subject: Re: Feature request for CHECKIN/OUT extension
>
>
> Hi,
>
> I have updated my proposal. The main changes are:
>
> 1) I am now using the defined element names for the response bodies
> (checkin-response, checkout-response) [Geoff, thanks for adding this to
> draft 17]
>
> 2) FORBIDDEN is 403, not 409.
>
> Julian
>
> --
>
> Feature request for CHECKIN/OUT extension
>
> In many cases, a versioning-aware client might want to display/include the
> URI of the version it's editing *while* it's edited. For instance, a
> versioning
> aware editor might include this as meta-information, or the author of a
> document might want to know the URI of the version *before* it's
> checked in.
> A well-known example is the W3C way of referring to document versions in
> recommendations: it contains HREFs to "the current version", to "this
> version"
> and to the "previous version". Something like this is currently impossible
> with deltaV, as the version URI is determined at the time of CHECKIN.
>
> Proposal:
>
> 1) Extend CHECKOUT to optionally return an "expected CHECKIN URI".
> 2) Extend CHECKIN to optionally use the "expected CHECKIN URI",
> failing the
> request if it's not possible to checkin the resource with the desired
> version URI (in which case a new "expected CHECKIN URI" is returned).
>
>
> I propose to pass the information in the request/response bodies of
> CHECKIN / CHECKOUT, such as:
>
> CHECKOUT method:
>
> >>REQUEST
>
> CHECKOUT /foo.html HTTP/1.1
> Host: www.webdav.org
> Content-Type: text/xml; charset="utf-8"
> Content-Length: xxxx
>
> <D:checkout xmlns:D="DAV:">
> <D:compute-expected-version-URI />
> </D:checkout>
>
>
> >>RESPONSE
>
> HTTP/1.1 200 OK
> Cache-Control: no-cache
> Content-Type: text/xml; charset="utf-8"
> Content-Length: xxxx
>
> <D:checkout-response xmlns:D="DAV:">
>
> <D:expected-version-URI>http://repo.webdav.org/his/23/ver/32</D:ex
> pected-ver
> sion-URI>
> </D:checkout-response>
>
> (Note: if the expected-version-URI cannot be computed, the server will
> simply not
> include it in it's answer).
>
>
> CHECKIN method:
>
>
> >>REQUEST
>
> CHECKIN /foo.html HTTP/1.1
> Host: www.webdav.org
> Content-Type: text/xml; charset="utf-8"
> Content-Length: xxxx
>
> <D:checkin xmlns:D="DAV:">
>
> <D:expected-version-URI>http://repo.webdav.org/his/23/ver/32</D:ex
> pected-ver
> sion-URI>
> </D:checkin>
>
> >>RESPONSE
>
> HTTP/1.1 201 Created
> Location: http://repo.webdav.org/his/23/ver/32
> Cache-Control: no-cache
>
> or
>
> >>RESPONSE
>
> HTTP/1.1 403 Forbidden
> Cache-Control: no-cache
> Content-Type: text/xml; charset="utf-8"
> Content-Length: xxxx
>
> <D:checkin-response xmlns:D="DAV:">
> <D:cannot-assign-expected-version-URI />
>
> <D:expected-version-URI>http://repo.webdav.org/his/23/ver/33</D:ex
> pected-ver
> sion-URI>
> </D:checkin-response>
>
>
Attachments
- text/xml attachment: draft-reschke-deltav-computecheckinuri.xml
Received on Sunday, 9 September 2001 13:50:56 UTC