Network Working Group A. Brown
Internet-Draft IBM
Intended status: Informational J. Reschke
Expires: December 14, 2009 greenbytes
June 12, 2009
Link Relations for Simple Version Navigation
draft-brown-versioning-link-relations-00
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Abstract
This specification defines Atom link relations for navigation between
a resource and its versions.
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Editorial Note (To be removed by RFC Editor before publication)
Please send comments to the Atom Syntax mailing list
(<http://www.imc.org/atom-syntax/>).
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Link Relations . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . . 5
Appendix A. Relationship to JCR and WebDAV . . . . . . . . . . . . 5
Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
This specification defines link relations that may be used on a
resource that exists in a system that supports versioning to navigate
among the different resources available, such as past versions.
2. Terminology
The terms below are borrowed from the Versioning Extensions to WebDAV
(Web Distributed Authoring and Versioning) ([RFC3253]).
Version-Controlled Resource, Checked-Out
When a versionable resource is put under version control, it
becomes a "version-controlled resource". A version-controlled
resource can be "checked out" to allow modification.
Checked-Out Resource
A "checked-out resource" is a resource under version control that
is in the checked-out state.
Version Resource
A "version resource", or simply "version", is a resource that
contains a copy of a particular state of a version-controlled
resource. A version is created by "checking in" a checked-out
resource. The server allocates a distinct new URL for each new
version.
Version History Resource
A "version history resource", or simply "version history", is a
resource that contains all the versions of a particular version-
controlled resource.
Predecessor, Successor, Ancestor, Descendant
When a version-controlled resource is checked out and then
subsequently checked in, the version that was checked out becomes
a "predecessor" of the version created by the checkin. A client
can specify multiple predecessors for a new version if the new
version is logically a merge of those predecessors. When a
version is connected to another version by traversing one or more
predecessor relations, it is called an "ancestor" of that version.
The inverse of the predecessor and ancestor relations are the
"successor" and "descendant" relations. Therefore, if X is a
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predecessor of Y, then Y is a successor of X, and if X is an
ancestor of Y, then Y is a descendant of X.
Root Version Resource
The "root version resource", or simply "root version", is the
version in a version history that is an ancestor of every other
version in that version history.
Working Resource
A "working resource" is a checked-out resource created by the
server at a server-defined URL when a version (instead of a
version-controlled resource) is checked out.
[[issue.working.resource: Is this true for JCR and CMIS as well?
Maybe we need to relax the definition? --jre]]
3. Link Relations
The following link relations are defined:
all-versions When included on a version controlled resource, this
link points to a resource containing the version history for this
resource.
latest-version When included on a version controlled resource, this
link points to a resource containing the latest (e.g., current)
version. [[issue.latest.version: I think "latest" is misleading,
as it may not be the "latest" when different branches are
involved. JCR 1.0 has "base version", defined as "The base
version of a particular node N is the one that will serve as the
default immediate predecessor of the next version of N that is
created." -- can we adopt that? (see
<http://www.day.com/specs/jcr/1.0/8.2.3_The_Base_Version.html>).
--jre]]
working-copy When included on a Checked-Out resource, this link
points to a Working Resource. [[issue.working.resource.2: I think
the working resource *is* checked out, and the link lives on
either a version or version controlled resource (which stays
checked in). --jre]]
predecessor-version When included on a version resource, this link
points to a resource containing the predecessor version in the
version history.
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successor-version When included on a version resource, this link
points to a resource containing the successor version in the
version history.
4. Examples
[[anchor2: To Be Done]]
5. Security Considerations
Automated agents should take care when these relation crosses
administrative domains (e.g., the URI has a different authority than
the current document).
6. IANA Considerations
The link relations defined in Section 3 are to be registered by IANA
per [RFC4287].
All link relations defined in this document will have the following
expected display characteristics:
Undefined; this relation can be used for background processing or
to provide extended functionality without displaying its value.
7. References
7.1. Normative References
[RFC4287] Nottingham, M. and R. Sayre, "The Atom Syndication
Format", RFC 4287, December 2005.
7.2. Informative References
[RFC3253] Clemm, G., Amsden, J., Ellison, T., Kaler, C., and J.
Whitehead, "Versioning Extensions to WebDAV (Web
Distributed Authoring and Versioning)", RFC 3253,
March 2002.
Appendix A. Relationship to JCR and WebDAV
[[anchor6: To Be Done: describe how versioning properties in JCR and
in WebDAV/DeltaV map to the newly defined link relations.]]
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Appendix B. Contributors
The content and concepts within are a product of the Content
Management Interoperability Services (CMIS) Technical Committee (TC)
at OASIS.
All members of the TC have contributed.
Authors' Addresses
Al Brown
IBM
3565 Harbor Blvd
Costa Mesa, California 92626
US
Email: albertcbrown@us.ibm.com
Julian F. Reschke
greenbytes GmbH
Hafenweg 16
Muenster, NW 48155
Germany
Email: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/
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