INTERNET-DRAFT Geoffrey Clemm, Rational Software
draft-ietf-deltav-versioning-19 Jim Amsden, IBM
Tim Ellison, IBM
Chris Kaler, Microsoft
Jim Whitehead, U.C. Santa Cruz
Expires March 26, 2002 September 26, 2001
Versioning Extensions to WebDAV
Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of RFC 2026, Section 10.
Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups. Note that other groups
may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference material
or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Abstract
This document specifies a set of methods, headers, and resource types
that define the WebDAV Versioning extensions to the HTTP/1.1 protocol.
WebDAV Versioning will minimize the complexity of clients that are
capable of interoperating with a variety of versioning repository
managers, to facilitate widespread deployment of applications capable of
utilizing the WebDAV Versioning services. WebDAV Versioning includes:
- Automatic versioning for versioning-unaware clients,
- Version history management,
- Workspace management,
- Baseline management,
- Activity management, and
- URL namespace versioning.
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Table of Contents
1 INTRODUCTION...........................................7
1.1 Relationship to WebDAV...............................7
1.2 Notational Conventions...............................8
1.3 Terms................................................8
1.4 Property Values.....................................11
1.4.1 Initial Property Value...........................11
1.4.2 Protected Property Value.........................11
1.4.3 Computed Property Value..........................12
1.4.4 Boolean Property Value...........................12
1.4.5 DAV:href Property Value..........................12
1.5 DAV Namespace XML Elements..........................12
1.6 Method Preconditions and Postconditions.............12
1.6.1 Example - CHECKOUT request.......................13
1.7 Clarification of COPY Semantics with Overwrite:T....13
1.8 Versioning Methods and Write Locks..................14
2 BASIC VERSIONING FEATURES.............................14
2.1 Basic Versioning Packages...........................14
2.2 Basic Versioning Semantics..........................15
2.2.1 Creating a Version-Controlled Resource...........15
2.2.2 Modifying a Version-Controlled Resource..........17
2.2.3 Reporting........................................19
3 VERSION-CONTROL FEATURE...............................19
3.1 Additional Resource Properties......................19
3.1.1 DAV:comment......................................19
3.1.2 DAV:creator-displayname..........................19
3.1.3 DAV:supported-method-set (protected).............20
3.1.4 DAV:supported-live-property-set (protected)......20
3.1.5 DAV:supported-report-set (protected).............20
3.2 Version-Controlled Resource Properties..............20
3.2.1 DAV:checked-in (protected).......................20
3.2.2 DAV:auto-version.................................21
3.3 Checked-Out Resource Properties.....................21
3.3.1 DAV:checked-out (protected)......................21
3.3.2 DAV:predecessor-set..............................22
3.4 Version Properties..................................22
3.4.1 DAV:predecessor-set (protected)..................22
3.4.2 DAV:successor-set (computed).....................22
3.4.3 DAV:checkout-set (computed)......................22
3.4.4 DAV:version-name (protected).....................22
3.5 VERSION-CONTROL Method..............................23
3.5.1 Example - VERSION-CONTROL........................24
3.6 REPORT Method.......................................24
3.7 DAV:version-tree Report.............................25
3.7.1 Example - DAV:version-tree Report................25
3.8 DAV:expand-property Report..........................27
3.8.1 Example - DAV:expand-property....................28
3.9 Additional OPTIONS Semantics........................29
3.10 Additional PUT Semantics...........................29
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3.11 Additional PROPFIND Semantics......................30
3.12 Additional PROPPATCH Semantics.....................31
3.13 Additional DELETE Semantics........................31
3.14 Additional COPY Semantics..........................32
3.15 Additional MOVE Semantics..........................32
3.16 Additional UNLOCK Semantics........................32
4 CHECKOUT-IN-PLACE FEATURE.............................33
4.1 Additional Version Properties.......................33
4.1.1 DAV:checkout-fork................................33
4.1.2 DAV:checkin-fork.................................34
4.2 Checked-Out Resource Properties.....................34
4.2.1 DAV:checkout-fork................................34
4.2.2 DAV:checkin-fork.................................34
4.3 CHECKOUT Method.....................................35
4.3.1 Example - CHECKOUT...............................36
4.4 CHECKIN Method......................................36
4.4.1 Example - CHECKIN................................38
4.5 UNCHECKOUT Method...................................38
4.5.1 Example - UNCHECKOUT.............................39
4.6 Additional OPTIONS Semantics........................39
5 VERSION-HISTORY FEATURE...............................39
5.1 Version History Properties..........................40
5.1.1 DAV:version-set (protected)......................40
5.1.2 DAV:root-version (computed)......................40
5.2 Additional Version-Controlled Resource Properties...40
5.2.1 DAV:version-history (computed)...................40
5.3 Additional Version Properties.......................40
5.3.1 DAV:version-history (computed)...................40
5.4 DAV:locate-by-history Report........................40
5.4.1 Example - DAV:locate-by-history Report...........41
5.5 Additional OPTIONS Semantics........................42
5.6 Additional DELETE Semantics.........................43
5.7 Additional COPY Semantics...........................43
5.8 Additional MOVE Semantics...........................43
5.9 Additional VERSION-CONTROL Semantics................43
5.10 Additional CHECKIN Semantics.......................44
6 WORKSPACE FEATURE.....................................44
6.1 Workspace Properties................................45
6.1.1 DAV:workspace-checkout-set (computed)............45
6.2 Additional Resource Properties......................45
6.2.1 DAV:workspace (protected)........................45
6.3 MKWORKSPACE Method..................................45
6.3.1 Example - MKWORKSPACE............................46
6.4 Additional OPTIONS Semantics........................46
6.4.1 Example - OPTIONS................................47
6.5 Additional DELETE Semantics.........................48
6.6 Additional MOVE Semantics...........................48
6.7 Additional VERSION-CONTROL Semantics................48
6.7.1 Example - VERSION-CONTROL........................49
7 UPDATE FEATURE........................................49
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7.1 UPDATE Method.......................................50
7.1.1 Example - UPDATE.................................50
7.2 Additional OPTIONS Semantics........................51
8 LABEL FEATURE.........................................51
8.1 Additional Version Properties.......................52
8.1.1 DAV:label-name-set (protected)...................52
8.2 LABEL Method........................................52
8.2.1 Example - Setting a label........................53
8.3 Label Header........................................54
8.4 Additional OPTIONS Semantics........................54
8.5 Additional GET Semantics............................54
8.6 Additional PROPFIND Semantics.......................55
8.7 Additional COPY Semantics...........................55
8.8 Additional CHECKOUT Semantics.......................56
8.9 Additional UPDATE Semantics.........................56
9 WORKING-RESOURCE FEATURE..............................57
9.1 Additional Version Properties.......................58
9.1.1 DAV:checkout-fork................................58
9.1.2 DAV:checkin-fork.................................58
9.2 Working Resource Properties.........................58
9.2.1 DAV:auto-update (protected)......................58
9.2.2 DAV:checkout-fork................................58
9.2.3 DAV:checkin-fork.................................58
9.3 CHECKOUT Method (applied to a version)..............58
9.3.1 Example - CHECKOUT of a version..................59
9.4 CHECKIN Method (applied to a working resource)......60
9.4.1 Example - CHECKIN of a working resource..........61
9.5 Additional OPTIONS Semantics........................61
9.6 Additional COPY Semantics...........................62
9.7 Additional MOVE Semantics...........................62
10 ADVANCED VERSIONING FEATURES........................62
10.1 Advanced Versioning Packages.......................62
10.2 Advanced Versioning Terms..........................63
11 MERGE FEATURE.......................................64
11.1 Additional Checked-Out Resource Properties.........65
11.1.1 DAV:merge-set...................................65
11.1.2 DAV:auto-merge-set..............................65
11.2 MERGE Method.......................................65
11.2.1 Example - MERGE.................................68
11.3 DAV:merge-preview Report...........................69
11.3.1 Example - DAV:merge-preview Report..............69
11.4 Additional OPTIONS Semantics.......................70
11.5 Additional DELETE Semantics........................71
11.6 Additional CHECKIN Semantics.......................71
12 BASELINE FEATURE....................................71
12.1 Version-Controlled Configuration Properties........72
12.1.1 DAV:baseline-controlled-collection (protected)..72
12.2 Checked-Out Configuration Properties...............72
12.2.1 DAV:subbaseline-set.............................72
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12.3 Baseline Properties................................72
12.3.1 DAV:baseline-collection (protected).............73
12.3.2 DAV:subbaseline-set (protected).................73
12.4 Additional Resource Properties.....................73
12.4.1 DAV:version-controlled-configuration (computed).73
12.5 Additional Workspace Properties....................73
12.5.1 DAV:baseline-controlled-collection-set(computed)73
12.6 BASELINE-CONTROL Method............................73
12.6.1 Example - BASELINE-CONTROL......................75
12.7 DAV:compare-baseline Report........................77
12.7.1 Example - DAV:compare-baseline Report...........77
12.8 Additional OPTIONS Semantics.......................78
12.9 Additional MKCOL Semantics.........................78
12.10 Additional COPY Semantics.........................79
12.11 Additional CHECKOUT Semantics.....................79
12.12 Additional CHECKIN Semantics......................79
12.13 Additional UPDATE Semantics.......................80
12.14 Additional MERGE Semantics........................81
13 ACTIVITY FEATURE....................................82
13.1 Activity Properties................................83
13.1.1 DAV:activity-version-set (computed).............83
13.1.2 DAV:activity-checkout-set (computed)............84
13.1.3 DAV:subactivity-set.............................84
13.1.4 DAV:current-workspace-set (computed)............84
13.2 Additional Version Properties......................84
13.2.1 DAV:activity-set................................84
13.3 Additional Checked-Out Resource Properties.........85
13.3.1 DAV:unreserved..................................85
13.3.2 DAV:activity-set................................85
13.4 Additional Workspace Properties....................85
13.4.1 DAV:current-activity-set........................85
13.5 MKACTIVITY Method..................................86
13.5.1 Example - MKACTIVITY............................86
13.6 DAV:latest-activity-version Report.................87
13.7 Additional OPTIONS Semantics.......................87
13.8 Additional DELETE Semantics........................88
13.9 Additional MOVE Semantics..........................88
13.10 Additional CHECKOUT Semantics.....................88
13.10.1 Example - CHECKOUT with an activity............89
13.11 Additional CHECKIN Semantics......................90
13.12 Additional MERGE Semantics........................90
14 VERSION-CONTROLLED-COLLECTION FEATURE...............91
14.1 Version-Controlled Collection Properties...........93
14.1.1 DAV:eclipsed-set (computed).....................93
14.2 Collection Version Properties......................94
14.2.1 DAV:version-controlled-binding-set (protected)..94
14.3 Additional OPTIONS Semantics.......................94
14.4 Additional DELETE Semantics........................94
14.5 Additional MKCOL Semantics.........................94
14.6 Additional COPY Semantics..........................95
14.7 Additional MOVE Semantics..........................95
14.8 Additional VERSION-CONTROL Semantics...............95
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14.9 Additional CHECKOUT Semantics......................96
14.10 Additional CHECKIN Semantics......................96
14.11 Additional UPDATE and MERGE Semantics.............96
15 INTERNATIONALIZATION CONSIDERATIONS.................97
16 SECURITY CONSIDERATIONS.............................98
16.1 Auditing and Traceability..........................98
16.2 Increased Need for Access Control..................98
16.3 Security Through Obscurity.........................98
16.4 Denial of Service..................................99
17 IANA CONSIDERATIONS.................................99
18 INTELLECTUAL PROPERTY...............................99
19 ACKNOWLEDGEMENTS...................................100
20 REFERENCES.........................................100
21 AUTHORS' ADDRESSES.................................101
22 APPENDIX A - RESOURCE CLASSIFICATION...............102
22.1 DeltaV-Compliant Unmapped URL.....................102
22.2 DeltaV-Compliant Resource.........................102
22.3 DeltaV-Compliant Collection.......................103
22.4 Versionable Resource..............................103
22.5 Version-Controlled Resource.......................103
22.6 Version...........................................103
22.7 Checked-In Version-Controlled Resource............103
22.8 Checked-Out Resource..............................104
22.9 Checked-Out Version-Controlled Resource...........104
22.10 Working Resource.................................104
22.11 Version History..................................104
22.12 Workspace........................................105
22.13 Activity.........................................105
22.14 Version-Controlled Collection....................105
22.15 Collection Version...............................105
22.16 Version-Controlled Configuration.................105
22.17 Baseline.........................................105
22.18 Checked-Out Version-Controlled Configuration.....106
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1 INTRODUCTION
This document specifies a set of methods, headers, and properties
that define the WebDAV versioning extensions to the HTTP/1.1
protocol. Versioning is concerned with tracking and accessing the
history of important states of a web resource, such as a standalone
web page. The benefits of versioning in the context of the
worldwide web include:
- A resource has an explicit history and a persistent identity
across the various states it has had during the course of that
history. It allows browsing through past and alternative versions
of a resource. Frequently the modification and authorship history
of a resource is critical information in itself.
- Resource states (versions) are given stable names that can
support externally stored links for annotation and link server
support. Both annotation and link servers frequently need to store
stable references to portions of resources that are not under their
direct control. By providing stable states of resources, version
control systems allow not only stable pointers into those
resources, but also well defined methods to determine the
relationships of those states of a resource.
WebDAV Versioning defines both basic and advanced versioning
functionality.
Basic versioning allows users to:
- Put a resource under version control
- Determine whether a resource is under version control
- Determine whether a resource update will automatically be
captured as a new version
- Create and access distinct versions of a resource
Advanced versioning provides additional functionality for parallel
development and configuration management of sets of web resources.
This document will first define the properties and method semantics
for the basic versioning features, and then define the additional
properties and method semantics for the advanced versioning
features. An implementer that is only interested in basic
versioning should skip the advanced versioning sections (Section 10
to Section 14).
1.1 Relationship to WebDAV
To maximize interoperability and the use of existing protocol
functionality, versioning support is designed as extensions to the
WebDAV protocol [RFC2518], which itself is an extension to the HTTP
protocol [RFC2616]. All method marshalling and postconditions
defined by RFC 2518 and RFC 2616 continue to hold, to ensure that
versioning unaware clients can interoperate successfully with
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versioning servers. Although the versioning extensions are
designed to be orthogonal to most aspects of the WebDAV and HTTP
protocols, a clarification to RFC 2518 is required for effective
interoperable versioning. This clarification is described in
Section 1.7.
1.2 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 RFC 2119.
The term "protected" is placed in parentheses following the
definition of a protected property (see Section 1.4.2).
The term "computed" is placed in parentheses following the
definition of a computed property (see Section 1.4.3).
When an XML element type in the "DAV:" namespace is referenced in
this document outside of the context of an XML fragment, the string
"DAV:" will be prefixed to the element type.
When a method is defined in this document, a list of preconditions
and postconditions will be defined for that method. If the
semantics of an existing method is being extended, a list of
additional preconditions and postconditions will be defined. A
precondition or postcondition is prefixed by a parenthesized XML
element type that identifies that precondition or postcondition
(see Section 1.6).
1.3 Terms
This document uses the terms defined in RFC 2616, in RFC 2518, and
in this section. Section 2.2 defines the semantic versioning model
underlying this terminology.
Version Control, Checked-In, Checked-Out
"Version control" is a set of constraints on how a resource can be
updated. A resource under version control is either in a "checked-
in" or "checked-out" state, and the version control constraints
apply only while the resource is in the checked-in state.
Versionable Resource
A "versionable resource" is a resource that can be put under
version control.
Version-Controlled Resource
When a versionable resource is put under version control, it
becomes a "version-controlled resource". A version-controlled
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resource can be "checked out" to allow modification of its content
or dead properties by standard HTTP and WebDAV methods.
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 (content and dead properties)
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, and this URL will never be
used to identify any resource other than that version. The content
and dead properties of a version never change.
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.
Version Name
A "version name" is a string chosen by the server to distinguish
one version of a version history from the other versions of that
version history. Versions from different version histories may
have the same version name.
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 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.
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Workspace Resource
A "workspace resource", or simply "workspace", is a collection that
contains at most one version-controlled resource for a given
version history (see Section 6).
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. Unlike a checked-out
version-controlled resource, a working resource is a deleted when
it is checked in.
Fork, Merge
When a second successor is added to a version, this creates a
"fork" in the version history. When a version is created with
multiple predecessors, this creates a "merge" in the version
history. A server may restrict the version history to be linear
(with no forks or merges), but an interoperable versioning client
should be prepared to deal with both forks and merges in the
version history.
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The following diagram illustrates several of the previous
definitions. Each box represents a version and each line between
two boxes represents a predecessor/successor relationship. For
example, it shows V3 is a predecessor of V5, V7 is a successor of
V5, V1 is an ancestor of V4, and V7 is a descendant of V4. It also
shows that there is a fork at version V2 and a merge at version V7.
History of foo.html
+---+
Root Version -------> | | V1
+---+ ^
| |
| |
+---+ |
Version Name ----> V2 | | | Ancestor
+---+ |
/ \ |
/ \ |
+---+ +---+
| | V3 | | V4
^ +---+ +---+
| | | |
Predecessor | | | |
+---+ +---+ |
| | V5 | | V6 | Descendant
+---+ +---+ |
Successor | \ / |
| \ / |
v +---+ v
| | V7
+---+
Label
A "label" is a name that can be used to select a version from a
version history. A label can be assigned by either a client or the
server. The same label can be used in different version histories.
1.4 Property Values
1.4.1 Initial Property Value
Unless an initial value of a property of a given type is defined by
this document, the initial value of a property of that type is
implementation dependent.
1.4.2 Protected Property Value
When a property of a specific kind of resource is "protected", the
property value cannot be updated on that kind of resource except by
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a method explicitly defined as updating that specific property. In
particular, a protected property cannot be updated with a PROPPATCH
request. Note that a given property can be protected on one kind
of resource, but not protected on another kind of resource.
1.4.3 Computed Property Value
When a property is "computed", its value is defined in terms of a
computation based on the content and other properties of that
resource, or even of some other resource. When the semantics of a
method is defined in this document, the effect of that method on
non-computed properties will be specified; the effect of that
method on computed properties will not be specified, but can be
inferred from the computation defined for those properties. A
computed property is always a protected property.
1.4.4 Boolean Property Value
Some properties take a Boolean value of either "false" or "true".
1.4.5 DAV:href Property Value
The DAV:href XML element is defined in RFC 2518, Section 12.3.
1.5 DAV Namespace XML Elements in Request and Response Bodies
Although WebDAV request and response bodies can be extended by
arbitrary XML elements, which can be ignored by the message
recipient, an XML element in the DAV namespace MUST NOT be used in
the request or response body of a versioning method unless that XML
element is explicitly defined in an IETF RFC.
1.6 Method Preconditions and Postconditions
A "precondition" of a method describes the state on the server that
must be true for that method to be performed. A "postcondition" of
a method describes the state on the server that must be true after
that method has completed. If a method precondition or
postcondition for a request is not satisfied, the response status
of the request MUST be either 403 (Forbidden) if the request should
not be repeated because it will always fail, or 409 (Conflict) if
it is expected that the user might be able to resolve the conflict
and resubmit the request.
In order to allow better client handling of 403 and 409 responses,
a distinct XML element type is associated with each method
precondition and postcondition of a request. When a particular
precondition is not satisfied or a particular postcondition cannot
be achieved, the appropriate XML element MUST be returned as the
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child of a top-level DAV:error element in the response body, unless
otherwise negotiated by the request. In a 207 Multi-Status
response, the DAV:error element would appear in the appropriate
DAV:responsedescription element.
1.6.1 Example - CHECKOUT request with DAV:must-be-checked-in response
>>REQUEST
CHECKOUT /foo.html HTTP/1.1
Host: www.webdav.org
>>RESPONSE
HTTP/1.1 409 Conflict
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
In this example, the request to CHECKOUT /foo.html fails because
/foo.html is not checked in.
1.7 Clarification of COPY Semantics with Overwrite:T
RFC 2518, Section 8.8.4 states:
"If a resource exists at the destination and the Overwrite header
is "T" then prior to performing the copy the server MUST perform a
DELETE with "Depth: infinity" on the destination resource."
The purpose of this sentence is to ensure that following a COPY,
all destination resources have the same content and dead properties
as the corresponding resources identified by the request-URL (where
a resource with a given name relative to the Destination URL
"corresponds" to a resource with the same name relative to the
request-URL). If at the time of the request, there already is a
resource at the destination that has the same resource type as the
corresponding resource at the request-URL, that resource MUST NOT
be deleted, but MUST be updated to have the content and dead
properties of its corresponding member. If a client wishes all
resources at the destination to be deleted prior to the COPY, it
MUST explicitly issue a DELETE request.
The difference between updating a resource and replacing a resource
with a new resource is especially important when resource history
is being maintained (the former adds to an existing history, while
the latter creates a new history). In addition, locking and access
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control constraints might allow you to update a resource, but not
allow you to delete it and create a new one in its place.
Note that this clarification does not apply to a MOVE request. A
MOVE request with Overwrite:T MUST perform the DELETE with
"Depth:infinity" on the destination resource prior to performing
the MOVE.
1.8 Versioning Methods and Write Locks
If a write-locked resource has a non-computed property defined by
this document, the property value MUST NOT be changed by a request
unless the appropriate lock token is included in the request.
Since every method introduced in this document other than REPORT
modifies at least one property defined by this document, every
versioning method other than REPORT is affected by a write lock. In
particular, the method MUST fail with a 423 (Locked) status if the
resource is write-locked and the appropriate token is not specified
in an If request header.
2 BASIC VERSIONING FEATURES
Each basic versioning feature defines extensions to existing HTTP
and WebDAV methods, as well as new resource types, live properties,
and methods.
2.1 Basic Versioning Packages
Although a server MAY support any combination of versioning
features, in order to minimize the complexity of a WebDAV basic
versioning client, a WebDAV basic versioning server SHOULD support
one of the following three "packages" (feature sets):
- Core-Versioning Package: version-control
- Basic-Server-Workspace Package: version-control, workspace,
version-history, checkout
- Basic-Client-Workspace Package: version-control, working-
resource, update, label
The core-versioning package supports linear versioning by both
versioning-aware and versioning-unaware clients. A versioning-aware
client can use reports and properties to access previous versions
of a version-controlled resource.
The basic workspace packages support parallel development of
version-controlled resources. Each client has its own
configuration of the shared version-controlled resources, and can
make changes to its configuration without disturbing that of
another client.
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In the basic-server-workspace package, all persistent state is
maintained on the server. Each client has its own workspace
resource allocated on the server, where each workspace identifies a
configuration of the shared version-controlled resources. Each
client makes changes to its workspace, and can transfer changes
when appropriate from one workspace to another. The server
workspace package is appropriate for clients with no local
persistent state, or for clients that wish to expose their working
configurations to other clients.
In the basic-client-workspace package, each client maintains in
local persistent storage the state for its configuration of the
shared version-controlled resources. When a client is ready to
make its changes visible to other clients, it allocates a set of
"working resources" on the server, updates the content and dead
properties of these working resources, and then uses the set of
working resources to update the version-controlled resources. The
working resources are used instead of directly updating the
version-controlled resources so that sets of consistent updates can
be prepared in parallel by multiple clients. Also, a working
resource allows a client to prepare a single update that requires
multiple server requests (e.g. updating both the content and dead
properties of a resource requires both a PUT and a PROPPATCH). The
client workspace package simplifies the server implementation by
requiring each client to maintain its own namespace, but this
requires that the clients have local persistent state, and does not
allow clients to expose their working configurations to other
clients.
A server that supports both basic workspace packages will
interoperate with all basic versioning clients.
2.2 Basic Versioning Semantics
2.2.1 Creating a Version-Controlled Resource
In order to track the history of the content and dead properties of
a versionable resource, a user can put the resource under version
control with a VERSION-CONTROL request. A VERSION-CONTROL request
performs three distinct operations:
1) It creates a new "version history resource". In basic
versioning, a version history resource is not assigned a URL, and
hence is not visible in the http scheme URL space. However, when
the version-history feature (see Section 5) is supported, this
changes, and each version history resource is assigned a new
distinct and unique server-defined URL.
2) It creates a new "version resource" and adds it to the new
version history resource. The body and dead properties of the new
version resource are a copy of those of the versionable resource.
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The server assigns the new version resource a new distinct and
unique URL.
3) It converts the versionable resource into a "version-controlled
resource". The version-controlled resource continues to be
identified by the same URL that identified it as a versionable
resource. As part of this conversion, it adds a DAV:checked-in
property, whose value contains the URL of the new version resource.
Note that a versionable resource and a version-controlled resource
are not new types of resources (i.e. they introduce no new
DAV:resourcetype), but rather are any type of resource that
supports the methods and live properties defined for them in this
document, in addition to all the methods and live properties
implied by their DAV:resourcetype. For example, a collection
(whose DAV:resourcetype is DAV:collection) is a versionable
resource if it supports the VERSION-CONTROL method, and is a
version-controlled resource if it supports the version-controlled
resource methods and live properties.
In the following example, foo.html is a versionable resource that
is put under version control. After the VERSION-CONTROL request
succeeds, there are two additional resources: a new version history
resource and a new version resource in that version history. The
versionable resource is converted into a version-controlled
resource, whose DAV:checked-in property identifies the new version
resource. The content and dead properties of a resource are
represented by the symbol appearing inside the box for that
resource (e.g. "S1" in the following example).
===VERSION-CONTROL==>
| +----+ version
| version- | | history
versionable | controlled +----+ resource
resource | resource |
/foo.html | /foo.html |
| v
+----+ | +----+ checked-in +----+ version
| S1 | | | S1 |----------->| S1 | resource
+----+ | +----+ +----+ /his/73/ver/1
Thus, whereas before the VERSION-CONTROL request there was only
one, non-version-controlled resource, after VERSION-CONTROL there
are three separate, distinct resources, each containing its own
state and properties: the version-controlled resource, the version
resource, and the version history resource. Since the version-
controlled resource and the version resource are separate, distinct
resources, when a method is applied to a version-controlled
resource, it is only applied to that version-controlled resource,
and is not applied to the version resource that is currently
identified by the DAV:checked-in property of that version-
controlled resource. Although the content and dead properties of a
checked-in version-controlled resource are required to be the same
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as those of its current DAV:checked-in version, its live properties
may differ. An implementation may optimize storage by retrieving
the content and dead properties of a checked-in version-controlled
resource from its current DAV:checked-in version rather than
storing them in the version-controlled resource, but this is just
an implementation optimization.
Normally, a resource is placed under version control with an
explicit VERSION-CONTROL request. A server MAY automatically place
every new versionable resource under version control. In this
case, the resulting state on the server MUST be the same as if the
client had explicitly applied a VERSION-CONTROL request to the
versionable resource.
2.2.2 Modifying a Version-Controlled Resource
In order to use methods like PUT and PROPPATCH to directly modify
the content or dead properties of a version-controlled resource,
the version-controlled resource must first be checked out. When
the checked-out resource is checked in, a new version is created in
the version history of that version-controlled resource. The
version that was checked out is remembered as the predecessor of
the new version.
The DAV:auto-version property (see Sections 3.2.2) of a checked-in
version-controlled resource determines how it responds to a method
that attempts to modify its content or dead properties. Possible
responses include:
- Fail the request. The resource requires an explicit CHECKOUT
request for it to be modified (see Sections 4 and 9.2.1).
- Automatically checkout the resource, perform the modification,
and automatically checkin the resource. This ensures that every
state of the resource is tracked by the server, but can result in
an excessive number of versions being created.
- Automatically checkout the resource, perform the modification,
and then if the resource is not write-locked, automatically checkin
the resource. If the resource is write-locked, it remains checked-
out until the write-lock is removed (either explicitly through a
subsequent UNLOCK request or implicitly through a time-out of the
write-lock). This helps a locking client avoid the proliferation
of versions, while still allowing a non-locking client to update
the resource.
- Automatically checkout the resource, perform the modification,
and then leave the resource checked out. If the resource is write-
locked, it will be automatically checked in when the write-lock is
removed, but an explicit CHECKIN operation (see Section 4.4) is
required for a non-write-locked resource. This minimizes the
number of new versions that will be created by a versioning unaware
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client, but only a versioning aware client can create new versions
of a non-write-locked resource.
- Fail the request unless the resource is write-locked. If it is
write-locked, automatically checkout the resource and perform the
modification. The resource is automatically checked in when the
write-lock is removed. This minimizes the number of new versions
that will be created by a versioning unaware client, but never
automatically checks out a resource that will not subsequently be
automatically checked in.
The following diagram illustrates the effect of the
checkout/checkin process on a version-controlled resource and its
version history. The symbol inside a box (S1, S2, S3) represents
the current content and dead properties of the resource represented
by that box. The symbol next to a box (V1, V2, V3) represents the
URL for that resource.
===checkout==> ===PUT==> ===checkin==>
/foo.html (version-controlled resource)
+----+ | +----+ | +----+ | +----+
| S2 | | | S2 | | | S3 | | | S3 |
+----+ | +----+ | +----+ | +----+
Checked-In=V2|Checked-Out=V2|Checked-Out=V2|Checked-In=V3
/his/73 (version history for /foo.html)
+----+ | +----+ | +----+ | +----+
| S1 | V1 | | S1 | V1 | | S1 | V1 | | S1 | V1
+----+ | +----+ | +----+ | +----+
| | | | | | |
| | | | | | |
+----+ | +----+ | +----+ | +----+
| S2 | V2 | | S2 | V2 | | S2 | V2 | | S2 | V2
+----+ | +----+ | +----+ | +----+
| | | |
| | | |
| | | +----+
| | | | S3 | V3
| | | +----+
Note that a version captures only a defined subset of the state of
a resource. In particular, a version of a basic resource captures
its content and dead properties, but not its live properties.
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2.2.3 Reporting
Some versioning information about a resource requires that
parameters be specified along with that request for information.
Included in basic versioning is the required support for an
extensible reporting mechanism, which includes a REPORT method as
well as a live property for determining what reports are supported
by a particular resource. The REPORT method is required by
versioning, but it can be used in non-versioning WebDAV extensions.
To allow a client to query the properties of all versions in the
version history of a specified version-controlled resource, basic
versioning provides the DAV:version-tree report (see Section 3.7).
A more powerful version history reporting mechanism is provided by
applying the DAV:expand-property report (see Section 3.8) to a
version history resource (see Section 5).
3 VERSION-CONTROL FEATURE
The version-control feature provides support for putting a resource
under version control creating an associated version-controlled
resource and version history resource as described in Section
2.2.1. A server indicates that it supports the version-control
feature by including the string "version-control" as a field in the
DAV header in the response to an OPTIONS request. The version-
control feature MUST be supported if any other versioning feature
is supported.
3.1 Additional Resource Properties
The version-control feature introduces the following REQUIRED
properties for any WebDAV resource.
3.1.1 DAV:comment
This property is used to track a brief comment about a resource
that is suitable for presentation to a user. The DAV:comment of a
version can be used to indicate why that version was created.
PCDATA value: string
3.1.2 DAV:creator-displayname
This property contains a description of the creator of the resource
that is suitable for presentation to a user. The DAV:creator-
displayname of a version can be used to indicate who created that
version.
PCDATA value: string
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3.1.3 DAV:supported-method-set (protected)
This property identifies the methods that are supported by the
resource. A method is supported by a resource if there is some
state of that resource for which an application of that method will
successfully satisfy all postconditions of that method, including
any additional postconditions added by the features supported by
that resource.
name value: a method name
3.1.4 DAV:supported-live-property-set (protected)
This property identifies the live properties that are supported by
the resource. A live property is supported by a resource if that
property has the semantics defined for that property. The value of
this property MUST identify all live properties defined by this
document that are supported by the resource, and SHOULD identify
all live properties that are supported by the resource.
ANY value: a property element type
3.1.5 DAV:supported-report-set (protected)
This property identifies the reports that are supported by the
resource.
ANY value: a report element type
3.2 Version-Controlled Resource Properties
The version-control feature introduces the following REQUIRED
properties for a version-controlled resource.
3.2.1 DAV:checked-in (protected)
This property appears on a checked-in version-controlled resource,
and identifies a version that has the same content and dead
properties as the version-controlled resource. This property is
removed when the resource is checked out, and then added back
(identifying a new version) when the resource is checked back in.
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3.2.2 DAV:auto-version
If the DAV:auto-version value is DAV:checkout-checkin, when a
modification request (such as PUT/PROPPATCH) is applied to a
checked-in version-controlled resource, the request is
automatically preceded by a checkout and followed by a checkin
operation.
If the DAV:auto-version value is DAV:checkout-unlocked-checkin,
when a modification request is applied to a checked-in version-
controlled resource, the request is automatically preceded by a
checkout operation. If the resource is not write-locked, the
request is automatically followed by a checkin operation.
If the DAV:auto-version value is DAV:checkout, when a modification
request is applied to a checked-in version-controlled resource, the
request is automatically preceded by a checkout operation.
If the DAV:auto-version value is DAV:locked-checkout, when a
modification request is applied to a write-locked checked-in
version-controlled resource, the request is automatically preceded
by a checkout operation.
If an update to a write-locked checked-in resource is automatically
preceded by a checkout of that resource, the checkout is associated
with the write-lock. When this write lock is removed (e.g. from an
UNLOCK or a lock timeout), if the resource has not yet been checked
in, the removal of the write lock is automatically preceded by a
checkin operation.
A server MAY refuse to allow the value of the DAV:auto-version
property to be modified, or MAY only support values from a subset
of the valid values.
3.3 Checked-Out Resource Properties
The version-control feature introduces the following REQUIRED
properties for a checked-out resource.
3.3.1 DAV:checked-out (protected)
This property identifies the version that was identified by the
DAV:checked-in property at the time the resource was checked out.
This property is removed when the resource is checked in.
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3.3.2 DAV:predecessor-set
This property determines the DAV:predecessor-set property of the
version that results from checking in this resource.
A server MAY reject attempts to modify the DAV:predecessor-set of a
version-controlled resource.
3.4 Version Properties
The version-control feature introduces the following REQUIRED
properties for a version.
3.4.1 DAV:predecessor-set (protected)
This property identifies each predecessor of this version. Except
for the root version, which has no predecessors, each version has
at least one predecessor.
3.4.2 DAV:successor-set (computed)
This property identifies each version whose DAV:predecessor-set
identifies this version.
3.4.3 DAV:checkout-set (computed)
This property identifies each checked-out resource whose
DAV:checked-out property identifies this version.
3.4.4 DAV:version-name (protected)
This property contains a server-defined string that is different
for each version in a given version history. This string is
intended for display to a user, unlike the URL of a version, which
is normally only used by a client and not displayed to a user.
PCDATA value: string
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3.5 VERSION-CONTROL Method
A VERSION-CONTROL request can be used to create a version-
controlled resource at the request-URL. It can be applied to a
versionable resource or to a version-controlled resource.
If the request-URL identifies a versionable resource, a new version
history resource is created, a new version is created whose content
and dead properties are copied from the versionable resource, and
the resource is given a DAV:checked-in property that is initialized
to identify this new version.
If the request-URL identifies a version-controlled resource, the
resource just remains under version-control. This allows a client
to be unaware of whether or not a server automatically puts a
resource under version control when it is created.
If a VERSION-CONTROL request fails, the server state preceding the
request MUST be restored.
Marshalling:
If a request body is included, it MUST be a DAV:version-control XML
element.
If a response body is included, it MUST be a DAV:version-control-
response XML element. Note that this document does not define any
elements for the VERSION-CONTROL response body, but the
DAV:version-control-response element is defined to ensure
interoperability between future extensions that do define elements
for the VERSION-CONTROL response body.
Postconditions:
(DAV:put-under-version-control): If the request-URL identified a
versionable resource at the time of the request, the request MUST
have created a new version history and MUST have created a new
version resource in that version history. The resource MUST have a
DAV:checked-in property that identifies the new version. The
content, dead properties, and DAV:resourcetype of the new version
MUST be the same as those of the resource. Note that an
implementation can choose to locate the version history and version
resources anywhere that it wishes. In particular, it could locate
them on the same host and server as the version-controlled
resource, on a different virtual host maintained by the same
server, on the same host maintained by a different server, or on a
different host maintained by a different server.
(DAV:must-not-change-existing-checked-in-out): If the request-URL
identified a resource already under version control at the time of
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the request, the request MUST NOT change the DAV:checked-in or
DAV:checked-out property of that version-controlled resource.
3.5.1 Example - VERSION-CONTROL
>>REQUEST
VERSION-CONTROL /foo.html HTTP/1.1
Host: www.webdav.org
Content-Length: 0
>>RESPONSE
HTTP/1.1 200 OK
In this example, /foo.html is put under version control. A new
version history is created for it, and a new version is created
that has a copy of the content and dead properties of /foo.html.
The DAV:checked-in property of /foo.html identifies this new
version.
3.6 REPORT Method
A REPORT request is an extensible mechanism for obtaining
information about a resource. Unlike a resource property, which
has a single value, the value of a report can depend on additional
information specified in the REPORT request body and in the REPORT
request headers.
Marshalling:
The body of a REPORT request specifies which report is being
requested, as well as any additional information that will be used
to customize the report.
The request MAY include a Depth header. If no Depth header is
included, Depth:0 is assumed.
The response body for a successful request MUST contain the
requested report.
If a Depth request header is included, the response MUST be a 207
Multi-Status. The request MUST be applied separately to the
collection itself and to all members of the collection that satisfy
the Depth value. The DAV:prop element of a DAV:response for a
given resource MUST contain the requested report for that resource.
Preconditions:
(DAV:supported-report): The specified report MUST be supported by
the resource identified by the request-URL.
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Postconditions:
(DAV:no-modification): The REPORT method MUST NOT have changed the
content or dead properties of any resource.
3.7 DAV:version-tree Report
The DAV:version-tree report describes the requested properties of
all the versions in the version history of a version. If the
report is requested for a version-controlled resource, it is
redirected to its DAV:checked-in or DAV:checked-out version.
The DAV:version-tree report MUST be supported by all version
resources and all version-controlled resources.
Marshalling:
The request body MUST be a DAV:version-tree XML element.
ANY value: a sequence of zero or more elements, with at most one
DAV:prop element.
prop: see RFC 2518, Section 12.11
The response body for a successful request MUST be a
DAV:multistatus XML element.
multistatus: see RFC 2518, Section 12.9
The response body for a successful DAV:version-tree REPORT request
MUST contain a DAV:response element for each version in the version
history of the version identified by the request-URL.
3.7.1 Example - DAV:version-tree Report
The version history drawn below would produce the following version
tree report.
foo.html History
+---+
| | V1
+---+
/ \
/ \
+---+ +---+
| | V2 | | V2.1.1
+---+ +---+
>>REQUEST
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REPORT /foo.html HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
>>RESPONSE
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://repo.webdav.org/his/23/ver/V1
V1
Fred
http://repo.webdav.org/his/23/ver/V2
http://repo.webdav.org/his/23/ver/V2.1.1
HTTP/1.1 200 OK
http://repo.webdav.org/his/23/ver/V2
V2
Fred
HTTP/1.1 200 OK
http://repo.webdav.org/his/23/ver/V2.1.1
V2.1.1
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Sally
HTTP/1.1 200 OK
3.8 DAV:expand-property Report
Many property values are defined as a DAV:href, or a set of
DAV:href elements. The DAV:expand-property report provides a
mechanism for retrieving in one request the properties from the
resources identified by those DAV:href elements. This report not
only decreases the number of requests required, but also allows the
server to minimize the number of separate read transactions
required on the underlying versioning store.
The DAV:expand-property report SHOULD be supported by all resources
that support the REPORT method.
Marshalling:
The request body MUST be a DAV:expand-property XML element.
name value: a property element type
namespace value: an XML namespace
The response body for a successful request MUST be a
DAV:multistatus XML element.
multistatus: see RFC 2518, Section 12.9
The properties reported in the DAV:prop elements of the
DAV:multistatus element MUST be those identified by the
DAV:property elements in the DAV:expand-property element. If there
are DAV:property elements nested within a DAV:property element,
then every DAV:href in the value of the corresponding property is
replaced by a DAV:response element whose DAV:prop elements report
the values of the properties identified by the nested DAV:property
elements. The nested DAV:property elements can in turn contain
DAV:property elements, so that multiple levels of DAV:href
expansion can be requested.
Note that a validating parser MUST be aware that the DAV:expand-
property report effectively modifies the DTD of every property by
replacing every occurrence of "href" in the DTD with "href |
response".
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3.8.1 Example - DAV:expand-property
This example describes how to query a version-controlled resource
to determine the DAV:creator-display-name and DAV:activity-set of
every version in the version history of that version-controlled
resource. This example assumes that the server supports the
version-history feature (see Section 5).
>>REQUEST
REPORT /foo.html HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
>>RESPONSE
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://www.webdav.org/foo.html
http://repo.webdav.org/his/23
http://repo.webdav.org/his/23/ver/1
Fred
http://www.webdav.org/ws/dev/sally
HTTP/1.1 200 OK
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http://repo.webdav.org/his/23/ver/2
Sally
http://repo.webdav.org/act/add-refresh-cmd
HTTP/1.1 200 OK
HTTP/1.1 200 OK
HTTP/1.1 200 OK
In this example, the DAV:creator-displayname and DAV:activity-set
properties of the versions in the DAV:version-set of the
DAV:version-history of http://www.webdav.org/foo.html are reported.
3.9 Additional OPTIONS Semantics
If the server supports the version-control feature, it MUST include
"version-control" as a field in the DAV response header from an
OPTIONS request on any resource that supports any versioning
properties, reports, or methods.
3.10 Additional PUT Semantics
Additional Preconditions:
(DAV:cannot-modify-version-controlled-content): If the request-URL
identifies a resource with a DAV:checked-in property, the request
MUST fail unless DAV:auto-version semantics will automatically
check out the resource.
(DAV:cannot-modify-version): If the request-URL identifies a
version, the request MUST fail.
If the request creates a new resource that is automatically placed
under version control, all preconditions for VERSION-CONTROL apply
to the request.
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Additional Postconditions:
(DAV:auto-checkout): If the resource was a checked-in version-
controlled resource whose DAV:auto-version property indicates it
should be automatically checked out but not automatically checked
in for a modification request, then the server MUST have
automatically checked out the resource prior to executing the
request. In particular, the value of the DAV:checked-out property
of the resource MUST be that of the DAV:checked-in property prior
to the request, the DAV:checked-in property MUST have been removed,
and the DAV:predecessor-set property MUST be initialized to be the
same as the DAV:checked-out property. If any part of the
checkout/update sequence failed, the status from the failed part of
the request MUST be returned, and the server state preceding the
request sequence MUST be restored.
(DAV:auto-checkout-checkin): If the resource was a checked-in
version-controlled resource whose DAV:auto-version property
indicates it should be automatically checked out and automatically
checked in for a modification request, then the server MUST have
automatically checked out the resource prior to executing the
request and automatically checked it in after the request. In
particular, the DAV:checked-in property of the resource MUST
identify a new version whose content and dead properties are the
same as those of the resource. The DAV:predecessor-set of the new
version MUST identify the version identified by the DAV:checked-in
property prior to the request. If any part of the
checkout/update/checkin sequence failed, the status from the failed
part of the request MUST be returned, and the server state
preceding the request sequence MUST be restored.
If the request creates a new resource, the new resource MAY have
automatically been placed under version control, and all
postconditions for VERSION-CONTROL apply to the request.
3.11 Additional PROPFIND Semantics
A DAV:allprop PROPFIND request SHOULD NOT return any of the
properties defined by this document. This allows a versioning
server to perform efficiently when a naive client, which does not
understand the cost of asking a server to compute all possible live
properties, issues a DAV:allprop PROPFIND request.
Additional Preconditions:
(DAV:supported-live-property): If the request attempts to access a
property defined by this document, the semantics of that property
MUST be supported by the server.
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3.12 Additional PROPPATCH Semantics
Additional Preconditions:
(DAV:cannot-modify-version-controlled-property): If the request
attempts to modify a dead property, same semantics as PUT (see
Section 3.10).
(DAV:cannot-modify-version): If the request attempts to modify a
dead property, same semantics as PUT (see Section 3.10).
(DAV:cannot-modify-protected-property): An attempt to modify a
property defined by this document as being protected for that kind
of resource MUST fail.
(DAV:supported-live-property): An attempt to modify a property
defined by this document whose semantics are not enforced by the
server MUST fail. This helps ensure that a client will be notified
when it is trying to use a property whose semantics are not
supported by the server.
Additional Postconditions:
(DAV:auto-checkout): If the request modified a dead property, same
semantics as PUT (see Section 3.10).
(DAV:auto-checkout-checkin): If the request modified a dead
property, same semantics as PUT (see Section 3.10).
3.13 Additional DELETE Semantics
Additional Preconditions:
(DAV:no-version-delete): A server MAY fail an attempt to DELETE a
version.
Additional Postconditions:
(DAV:update-predecessor-set): If a version was deleted, the server
MUST have replaced any reference to that version in a
DAV:predecessor-set by a copy of the DAV:predecessor-set of the
deleted version.
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3.14 Additional COPY Semantics
Additional Preconditions:
If the request creates a new resource that is automatically placed
under version control, all preconditions for VERSION-CONTROL apply
to the request.
Additional Postconditions:
(DAV:must-not-copy-versioning-property): A property defined by this
document MUST NOT have been copied to the new resource created by
this request, but instead that property of the new resource MUST
have the default initial value it would have had if the new
resource had been created by a non-versioning method such as PUT or
a MKCOL.
(DAV:auto-checkout): If the destination is a version-controlled
resource, same semantics as PUT (see Section 3.10).
(DAV:auto-checkout-checkin): If the destination is a version-
controlled resource, same semantics as PUT (see Section 3.10).
(DAV:copy-creates-new-resource): If the source of a COPY is a
version-controlled resource or version, and if there is no resource
at the destination of the COPY, then the COPY creates a new non-
version-controlled resource at the destination of the COPY. The
new resource MAY automatically be put under version control, but
the resulting version-controlled resource MUST be associated with a
new version history created for that new version-controlled
resource, and all postconditions for VERSION-CONTROL apply to the
request.
3.15 Additional MOVE Semantics
Additional Preconditions:
(DAV:cannot-rename-version): If the request-URL identifies a
version, the request MUST fail.
Additional Postconditions:
(DAV:preserve-versioning-properties): When a resource is moved from
a source URL to a destination URL, a property defined by this
document MUST have the same value at the destination URL as it had
at the source URL.
3.16 Additional UNLOCK Semantics
Note that these semantics apply both to an explicit UNLOCK request,
as well as to the removal of a lock because of a lock timeout. If
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a precondition or postcondition cannot be satisfied, the lock
timeout MUST NOT occur.
Additional Preconditions:
(DAV:version-history-is-tree): If the request-URL identifies a
checked-out version-controlled resource that will be automatically
checked in when the lock is removed, then the versions identified
by the DAV:predecessor-set of the checked-out resource MUST be
descendants of the root version of the version history for the
DAV:checked-out version.
Additional Postconditions:
(DAV:auto-checkin): If the request-URL identified a checked-out
version-controlled resource that had been automatically checked out
because of its DAV:auto-version property, the request MUST have
created a new version in the version history of the DAV:checked-out
version. The request MUST have allocated a URL for the version
that MUST NOT have previously identified any other resource, and
MUST NOT ever identify a resource other than this version. The
content, dead properties, DAV:resourcetype, and DAV:predecessor-set
of the new version MUST be copied from the checked-out resource.
The DAV:version-name of the new version MUST be set to a server-
defined value distinct from all other DAV:version-name values of
other versions in the same version history. The request MUST have
removed the DAV:checked-out property of the version-controlled
resource, and MUST have added a DAV:checked-in property that
identifies the new version.
4 CHECKOUT-IN-PLACE FEATURE
With the version-control feature, WebDAV locking can be used to
avoid the proliferation of versions that would result if every
modification to a version-controlled resource produced a new
version. The checkout-in-place feature provides an alternative
mechanism that allows a client to explicitly check out and check in
a resource to create a new version.
4.1 Additional Version Properties
The checkout-in-place feature introduces the following REQUIRED
properties for a version.
4.1.1 DAV:checkout-fork
This property controls the behavior of CHECKOUT when a version
already is checked out or has a successor. If the DAV:checkout-
fork of a version is DAV:forbidden, a CHECKOUT request MUST fail if
it would result in that version appearing in the DAV:predecessor-
set or DAV:checked-out property of more than one version or
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checked-out resource. If DAV:checkout-fork is DAV:discouraged,
such a CHECKOUT request MUST fail unless DAV:fork-ok is specified
in the CHECKOUT request body.
A server MAY reject attempts to modify the DAV:checkout-fork of a
version.
ANY value: A sequence of elements with at most one DAV:discouraged
or DAV:forbidden element.
4.1.2 DAV:checkin-fork
This property controls the behavior of CHECKIN when a version
already has a successor. If the DAV:checkin-fork of a version is
DAV:forbidden, a CHECKIN request MUST fail if it would result in
that version appearing in the DAV:predecessor-set of more than one
version. If DAV:checkin-fork is DAV:discouraged, such a CHECKIN
request MUST fail unless DAV:fork-ok is specified in the CHECKIN
request body.
A server MAY reject attempts to modify the DAV:checkout-fork of a
version.
ANY value: A sequence of elements with at most one DAV:discouraged
or DAV:forbidden element.
4.2 Checked-Out Resource Properties
The checkout-in-place feature introduces the following REQUIRED
properties for a checked-out resource.
4.2.1 DAV:checkout-fork
This property determines the DAV:checkout-fork property of the
version that results from checking in this resource.
4.2.2 DAV:checkin-fork
This property determines the DAV:checkin-fork property of the
version that results from checking in this resource.
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4.3 CHECKOUT Method (applied to a version-controlled resource)
A CHECKOUT request can be applied to a checked-in version-
controlled resource to allow modifications to the content and dead
properties of that version-controlled resource.
If a CHECKOUT request fails, the server state preceding the request
MUST be restored.
Marshalling:
If a request body is included, it MUST be a DAV:checkout XML
element.
ANY value: A sequence of elements with at most one DAV:fork-ok
element.
If a response body is included, it MUST be a DAV:checkout-response
XML element.
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:must-be-checked-in): If a version-controlled resource is being
checked out, it MUST have a DAV:checked-in property.
(DAV:checkout-of-version-with-descendant-is-forbidden): If the
DAV:checkout-fork property of the version being checked out is
DAV:forbidden, the request MUST fail if a version identifies that
version in its DAV:predecessor-set.
(DAV:checkout-of-version-with-descendant-is-discouraged): If the
DAV:checkout-fork property of the version being checked out is
DAV:discouraged, the request MUST fail if a version identifies that
version in its DAV:predecessor-set unless DAV:fork-ok is specified
in the request body.
(DAV:checkout-of-checked-out-version-is-forbidden): If the
DAV:checkout-fork property of the version being checked out is
DAV:forbidden, the request MUST fail if a checked-out resource
identifies that version in its DAV:checked-out property.
(DAV:checkout-of-checked-out-version-is-discouraged): If the
DAV:checkout-fork property of the version being checked out is
DAV:discouraged, the request MUST fail if a checked-out resource
identifies that version in its DAV:checked-out property unless
DAV:fork-ok is specified in the request body.
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Postconditions:
(DAV:is-checked-out): The checked-out resource MUST have a
DAV:checked-out property that identifies the DAV:checked-in version
preceding the checkout. The version-controlled resource MUST NOT
have a DAV:checked-in property.
(DAV:initialize-predecessor-set): The DAV:predecessor-set property
of the checked-out resource MUST be initialized to be the
DAV:checked-out version.
4.3.1 Example - CHECKOUT of a version-controlled resource
>>REQUEST
CHECKOUT /foo.html HTTP/1.1
Host: www.webdav.org
Content-Length: 0
>>RESPONSE
HTTP/1.1 200 OK
Cache-Control: no-cache
In this example, the version-controlled resource /foo.html is
checked out.
4.4 CHECKIN Method (applied to a version-controlled resource)
A CHECKIN request can be applied to a checked-out version-
controlled resource to produce a new version whose content and dead
properties are copied from the checked-out resource.
If a CHECKIN request fails, the server state preceding the request
MUST be restored.
Marshalling:
If a request body is included, it MUST be a DAV:checkin XML
element.
ANY value: A sequence of elements with at most one DAV:keep-
checked-out element and at most one DAV:fork-ok element.
If a response body is included, it MUST be a DAV:checkin-response
XML element.
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The response to a successful request MUST include a Location header
containing the URL for the new version created by the checkin.
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:must-be-checked-out): The request-URL MUST identify a resource
with a DAV:checked-out property.
(DAV:version-history-is-tree) The versions identified by the
DAV:predecessor-set of the checked-out resource MUST be descendants
of the root version of the version history for the DAV:checked-out
version.
(DAV:checkin-fork-forbidden): A CHECKIN request MUST fail if it
would cause a version whose DAV:checkin-fork is DAV:forbidden to
appear in the DAV:predecessor-set of more than one version.
(DAV:checkin-fork-discouraged): A CHECKIN request MUST fail if it
would cause a version whose DAV:checkin-fork is DAV:discouraged to
appear in the DAV:predecessor-set of more than one version, unless
DAV:fork-ok is specified in the request body.
Postconditions:
(DAV:create-version): The request MUST have created a new version
in the version history of the DAV:checked-out version. The request
MUST have allocated a distinct new URL for the new version, and
that URL MUST NOT ever identify any resource other than that
version. The URL for the new version MUST be returned in a Location
response header.
(DAV:initialize-version-content-and-properties): The content, dead
properties, DAV:resourcetype, and DAV:predecessor-set of the new
version MUST be copied from the checked-out resource. The
DAV:version-name of the new version MUST be set to a server-defined
value distinct from all other DAV:version-name values of other
versions in the same version history.
(DAV:checked-in): If the request-URL identifies a version-
controlled resource and DAV:keep-checked-out is not specified in
the request body, the DAV:checked-out property of the version-
controlled resource MUST have been removed and a DAV:checked-in
property that identifies the new version MUST have been added.
(DAV:keep-checked-out): If DAV:keep-checked-out is specified in the
request body, the DAV:checked-out property of the checked-out
resource MUST have been updated to identify the new version.
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4.4.1 Example - CHECKIN
>>REQUEST
CHECKIN /foo.html HTTP/1.1
Host: www.webdav.org
Content-Length: 0
>>RESPONSE
HTTP/1.1 201 Created
Location: http://repo.webdav.org/his/23/ver/32
Cache-Control: no-cache
In this example, version-controlled resource /foo.html is checked
in, and a new version is created at
http://repo.webdav.org/his/23/ver/32.
4.5 UNCHECKOUT Method
An UNCHECKOUT request can be applied to a checked-out version-
controlled resource to cancel the CHECKOUT and restore the pre-
CHECKOUT state of the version-controlled resource.
If an UNCHECKOUT request fails, the server MUST undo any partial
effects of the UNCHECKOUT request.
Marshalling:
If a request body is included, it MUST be a DAV:uncheckout XML
element.
If a response body is included, it MUST be a DAV:uncheckout-
response XML element.
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:must-be-checked-out-version-controlled-resource): The request-
URL MUST identify a version-controlled resource with a DAV:checked-
out property.
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Postconditions:
(DAV:cancel-checked-out): The value of the DAV:checked-in property
is that of the DAV:checked-out property prior to the request, and
the DAV:checked-out property has been removed.
(DAV:restore-content-and-dead-properties): The content and dead
properties of the version-controlled resource are copies of its
DAV:checked-in version.
4.5.1 Example - UNCHECKOUT
>>REQUEST
UNCHECKOUT /foo.html HTTP/1.1
Host: www.webdav.org
Content-Length: 0
>>RESPONSE
HTTP/1.1 200 OK
Cache-Control: no-cache
In this example, the content and dead properties of the version-
controlled resource identified by http://www.webdav.org/foo.html
are restored to their values preceding the most recent CHECKOUT of
that version-controlled resource.
4.6 Additional OPTIONS Semantics
If a server supports the checkout-in-place feature, it MUST include
"checkout-in-place" as a field in the DAV response header from an
OPTIONS request on any resource that supports any versioning
properties, reports, or methods.
5 VERSION-HISTORY FEATURE
It is often useful to have access to a version history even after
all version-controlled resources for that version history have been
deleted. A server can provide this functionality by supporting
version history resources. A version history resource is a
resource that exists in a server defined namespace and therefore is
unaffected by any deletion or movement of version-controlled
resources. A version history resource is an appropriate place to
add a property that logically applies to all states of a resource.
The DAV:expand-property report (see Section 3.8) can be applied to
the DAV:version-set of a version history resource to provide a
variety of useful reports on all versions in that version history.
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5.1 Version History Properties
The DAV:resourcetype of a version history MUST be DAV:version-
history.
The version-history feature introduces the following REQUIRED
properties for a version history.
5.1.1 DAV:version-set (protected)
This property identifies each version of this version history.
5.1.2 DAV:root-version (computed)
This property identifies the root version of this version history.
5.2 Additional Version-Controlled Resource Properties
The version-history feature introduces the following REQUIRED
property for a version-controlled resource.
5.2.1 DAV:version-history (computed)
This property identifies the version history resource for the
DAV:checked-in or DAV:checked-out version of this version-
controlled resource.
5.3 Additional Version Properties
The version-history feature introduces the following REQUIRED
property for a version.
5.3.1 DAV:version-history (computed)
This property identifies the version history that contains this
version.
5.4 DAV:locate-by-history Report
Many properties identify a version from some version history. It
is often useful to be able to efficiently locate a version-
controlled resource for that version history. The DAV:locate-by-
history report can be applied to a collection to locate the
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collection member that is a version-controlled resource for a
specified version history resource.
Marshalling:
The request body MUST be a DAV:locate-by-history XML element.
prop: see RFC 2518, Section 12.11
The response body for a successful request MUST be a
DAV:multistatus XML element containing every version-controlled
resource that is a member of the collection identified by the
request-URL, and whose DAV:version-history property identifies one
of the version history resources identified by the request body.
The DAV:prop element in the request body identifies which
properties should be reported in the DAV:prop elements in the
response body.
Preconditions:
(DAV:must-be-version-history): Each member of the DAV:version-
history-set element in the request body MUST identify a version
history resource.
5.4.1 Example - DAV:locate-by-history Report
>>REQUEST
REPORT /ws/public HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://repo.webdav.org/his/23
http://repo.webdav.org/his/84
http://repo.webdav.org/his/129
>>RESPONSE
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
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http://www.webdav.org/ws/public/x/test.html
http://repo.webdav.org/his/23
HTTP/1.1 200 OK
In this example, there is only one version-controlled member of
/ws/public that is a version-controlled resource for one of the
three specified version history resources. In particular,
/ws/public/x/test.html is the version-controlled resource for
http://repo.webdav.org/his/23.
5.5 Additional OPTIONS Semantics
If the server supports the version-history feature, it MUST include
"version-history" as a field in the DAV response header from an
OPTIONS request on any resource that supports any versioning
properties, reports, or methods.
A DAV:version-history-collection-set element MAY be included in the
request body to identify collections that may contain version
history resources.
Additional Marshalling:
If an XML request body is included, it MUST be a DAV:options XML
element.
ANY value: A sequence of elements with at most one DAV:version-
history-collection-set element.
If an XML response body for a successful request is included, it
MUST be a DAV:options-response XML element.
ANY value: A sequence of elements with at most one DAV:version-
history-collection-set element.
If DAV:version-history-collection-set is included in the request
body, the response body for a successful request MUST contain a
DAV:version-history-collection-set element identifying collections
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that may contain version histories. An identified collection MAY
be the root collection of a tree of collections, all of which may
contain version histories. Since different servers can control
different parts of the URL namespace, different resources on the
same host MAY have different DAV:version-history-collection-set
values. The identified collections MAY be located on different
hosts from the resource.
5.6 Additional DELETE Semantics
Additional Postconditions:
(DAV:delete-version-set): If the request deleted a version history,
the request MUST have deleted all versions in the DAV:version-set
of that version history, and MUST have satisfied the
postconditions for version deletion (see Section 3.13).
(DAV:version-history-has-root): If the request deleted the root
version of a version history, the request MUST have updated the
DAV:root-version of the version history to refer to another version
that is an ancestor of all other remaining versions in that version
history. A result of this postcondition is that every version
history will have at least one version, and the only way to delete
all versions is to delete the version history resource.
5.7 Additional COPY Semantics
Additional Preconditions:
(DAV:cannot-copy-history): If the request-URL identifies a version
history, the request MUST fail. In order to create another version
history whose versions have the same content and dead properties,
the appropriate sequence of VERSION-CONTROL, CHECKOUT, PUT,
PROPPATCH, and CHECKIN requests must be made.
5.8 Additional MOVE Semantics
Additional Preconditions:
(DAV:cannot-rename-history): If the request-URL identifies a
version history, the request MUST fail.
5.9 Additional VERSION-CONTROL Semantics
Additional Postconditions:
(DAV:new-version-history): If the request created a new version
history, the request MUST have allocated a new server-defined URL
for that version history that MUST NOT have previously identified
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any other resource, and MUST NOT ever identify a resource other
than this version history.
5.10 Additional CHECKIN Semantics
Additional Postconditions:
(DAV:add-to-history): A URL for the new version resource MUST have
been added to the DAV:version-set of the version history of the
DAV:checked-out version.
6 WORKSPACE FEATURE
In order to allow multiple users to work concurrently on adding
versions to the same version history, it is necessary to allocate
on the server multiple checked-out resources for the same version
history. Even if only one user is making changes to a resource,
that user will sometimes wish to create a "private" version, and
then to expose that version at a later time. One way to provide
this functionality depends on the client keeping track of its
current set of checked-out resources. This is the working-resource
feature defined in Section 8. The other way to provide this
functionality avoids the need for persistent state on the client,
and instead has the server maintain a human meaningful namespace
for related sets of checked-out resources. This is the workspace
feature defined in this section.
The workspace feature introduces a "workspace resource". A
workspace resource is a collection whose members are related
version-controlled and non-version-controlled resources. Multiple
workspaces may be used to expose different versions and
configurations of a set of version-controlled resources
concurrently. In order to make changes to a version-controlled
resource in one workspace visible in another workspace, that
version-controlled resource must be checked in, and then the
corresponding version-controlled resource in the other workspace
can be updated to display the content and dead properties of the
new version.
In order to ensure unambiguous merging (see Section 11) and
baselining (see Section 12) semantics, a workspace may contain at
most one version-controlled resource for a given version history.
This is required for unambiguous merging because the MERGE method
must identify which version-controlled resource is to be the merge
target of a given version. This is required for unambiguous
baselining because a baseline can only select one version for a
given version-controlled resource.
Initially, an empty workspace can be created. Non-version-
controlled resources can then be added to the workspace with
standard WebDAV requests such as PUT and MKCOL. Version-controlled
resources can be added to the workspace with VERSION-CONTROL
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requests. If the baseline feature is supported, collections in the
workspace can be placed under baseline control, and then
initialized by existing baselines.
6.1 Workspace Properties
The workspace feature introduces the following REQUIRED property
for a workspace.
6.1.1 DAV:workspace-checkout-set (computed)
This property identifies each checked-out resource whose
DAV:workspace property identifies this workspace.
6.2 Additional Resource Properties
The workspace feature introduces the following REQUIRED property
for a WebDAV resource.
6.2.1 DAV:workspace (protected)
The DAV:workspace property of a workspace resource MUST identify
itself. The DAV:workspace property of any other type of resource
MUST be the same as the DAV:workspace of its parent collection.
6.3 MKWORKSPACE Method
A MKWORKSPACE request creates a new workspace resource. A server
MAY restrict workspace creation to particular collections, but a
client can determine the location of these collections from a
DAV:workspace-collection-set OPTIONS request (see Section 6.4).
If a MKWORKSPACE request fails, the server state preceding the
request MUST be restored.
Marshalling:
If a request body is included, it MUST be a DAV:mkworkspace XML
element.
If a response body is included, it MUST be a DAV:mkworkspace-
response XML element.
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The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:resource-must-be-null): A resource MUST NOT exist at the
request-URL.
(DAV:workspace-location-ok): The request-URL MUST identify a
location where a workspace can be created.
Postconditions:
(DAV:initialize-workspace): A new workspace exists at the request-
URL. The DAV:resourcetype of the workspace MUST be DAV:collection.
The DAV:workspace of the workspace MUST identify the workspace.
6.3.1 Example - MKWORKSPACE
>>REQUEST
MKWORKSPACE /ws/public HTTP/1.1
Host: www.webdav.org
Content-Length: 0
>>RESPONSE
HTTP/1.1 201 Created
Cache-Control: no-cache
In this example, a new workspace is created at
http://www.webdav.org/ws/public.
6.4 Additional OPTIONS Semantics
If a server supports the workspace feature, it MUST include
"workspace" as a field in the DAV response header from an OPTIONS
request on any resource that supports any versioning properties,
reports, or methods.
If a server supports the workspace feature, it MUST also support
the checkout-in-place feature and the version-history feature.
A DAV:workspace-collection-set element MAY be included in the
request body to identify collections that may contain workspace
resources.
Additional Marshalling:
If an XML request body is included, it MUST be a DAV:options XML
element.
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ANY value: A sequence of elements with at most one DAV:workspace-
collection-set element.
If an XML response body for a successful request is included, it
MUST be a DAV:options-response XML element.
ANY value: A sequence of elements with at most one DAV:workspace-
collection-set element.
If DAV:workspace-collection-set is included in the request body,
the response body for a successful request MUST contain a
DAV:workspace-collection-set element identifying collections that
may contain workspaces. An identified collection MAY be the root
collection of a tree of collections, all of which may contain
workspaces. Since different servers can control different parts of
the URL namespace, different resources on the same host MAY have
different DAV:workspace-collection-set values. The identified
collections MAY be located on different hosts from the resource.
6.4.1 Example - OPTIONS
>>REQUEST
OPTIONS /doc HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
>>RESPONSE
HTTP/1.1 200 OK
DAV: 1
DAV: version-control,checkout-in-place,version-history,workspace
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://repo.webdav.org/his
http://www.webdav.org/public/ws
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http://www.webdav.org/private/ws
In this example, the server indicates that it provides Class 1 DAV
support and basic-server-workspace versioning support. In
addition, the server indicates the requested locations of the
version history resources and the workspace resources.
6.5 Additional DELETE Semantics
Additional Postconditions:
(DAV:delete-workspace-members): If a workspace is deleted, any
resource that identifies that workspace in its DAV:workspace
property MUST be deleted.
6.6 Additional MOVE Semantics
Additional Postconditions:
(DAV:workspace-member-moved): If the request-URL did not identify a
workspace, the DAV:workspace of the destination MUST have been
updated to have the same value as the DAV:workspace of the parent
collection of the destination.
(DAV:workspace-moved): If the request-URL identified a workspace,
any reference to that workspace in a DAV:workspace property MUST
have been updated to refer to the new location of that workspace.
6.7 Additional VERSION-CONTROL Semantics
A VERSION-CONTROL request can be used to create a new version-
controlled resource for an existing version history. This allows
the creation of version-controlled resources for the same version
history in multiple workspaces.
Additional Marshalling:
ANY value: A sequence of elements with at most one DAV:version
element.
Additional Preconditions:
(DAV:cannot-add-to-existing-history): If the DAV:version-control
request body element contains a DAV:version element, the request-
URL MUST NOT identify a resource.
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(DAV:must-be-version): The DAV:href of the DAV:version element MUST
identify a version.
(DAV:one-version-controlled-resource-per-history-per-workspace): If
the DAV:version-control request body specifies a version, and if
the request-URL is a member of a workspace, then there MUST NOT
already be a version-controlled member of that workspace whose
DAV:checked-in or DAV:checked-out property identifies any version
from the version history of the version specified in the request
body.
Additional Postconditions:
(DAV:new-version-controlled-resource): If the request-URL did NOT
identify a resource, a new version-controlled resource exists at
the request-URL whose content and dead properties are initialized
by those of the version in the request body, and whose DAV:checked-
in property identifies that version.
6.7.1 Example - VERSION-CONTROL (using an existing version history)
>>REQUEST
VERSION-CONTROL /ws/public/bar.html HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://repo.webdav.org/his/12/ver/V3
>>RESPONSE
HTTP/1.1 201 Created
Cache-Control: no-cache
In this example, a new version-controlled resource is created at
/ws/public/bar.html. The content and dead properties of the new
version-controlled resource are initialized to be the same as those
of the version identified by http://repo.webdav.org/his/12/ver/V3.
7 UPDATE FEATURE
The update feature provides a mechanism for changing the state of a
checked-in version-controlled resource to be that of another
version from the version history of that resource.
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7.1 UPDATE Method
The UPDATE method modifies the content and dead properties of a
checked-in version-controlled resource (the "update target") to be
those of a specified version (the "update source") from the version
history of that version-controlled resource.
The response to an UPDATE request identifies the resources modified
by the request, so that a client can efficiently update any cached
state it is maintaining. Extensions to the UPDATE method allow
multiple resources to be modified from a single UPDATE request (see
Section 12.13).
Marshalling:
The request body MUST be a DAV:update element.
ANY value: A sequence of elements with at most one DAV:version
element and at most one DAV:prop element.
prop: see RFC 2518, Section 12.11
The response for a successful request MUST be a 207 Multi-Status,
where the DAV:multistatus XML element in the response body
identifies all resources that have been modified by the request.
multistatus: see RFC 2518, Section 12.9
The response MUST include a Cache-Control:no-cache header.
Postconditions:
(DAV:update-content-and-properties): If the DAV:version element in
the request body identified a version that is in the same version
history as the DAV:checked-in version of a version-controlled
resource identified by the request-URL, then the content and dead
properties of that version-controlled resource MUST be the same as
those of the version specified by the DAV:version element, and the
DAV:checked-in property of the version-controlled resource MUST
identify that version. The request-URL MUST appear in a
DAV:response element in the response body.
(DAV:report-properties): If DAV:prop is specified in the request
body, the properties specified in the DAV:prop element MUST be
reported in the DAV:response elements in the response body.
7.1.1 Example - UPDATE
>>REQUEST
UPDATE /foo.html HTTP/1.1
Host: www.webdav.org
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Content-type: text/xml; charset="utf-8"
Content-Length: xxxx
http://repo.webdav.org/his/23/ver/33
>>RESPONSE
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
Cache-Control: no-cache
http://www.webdav.org/foo.html
In this example, the content and dead properties of
http://repo.webdav.org/his/23/ver/33 are copied to the version-
controlled resource /foo.html, and the DAV:checked-in property of
/foo.html is updated to refer to
http://repo.webdav.org/his/23/ver/33.
7.2 Additional OPTIONS Semantics
If the server supports the update feature, it MUST include "update"
as a field in the DAV response header from an OPTIONS request on
any resource that supports any versioning properties, reports, or
methods.
8 LABEL FEATURE
A version "label" is a string that distinguishes one version in a
version history from all other versions in that version history. A
label can automatically be assigned by a server, or it can be
assigned by a client in order to provide a meaningful name for that
version. A given version label can be assigned to at most one
version of a given version history, but client assigned labels can
be reassigned to another version at any time. Note that although a
given label can be applied to at most one version from the same
version history, the same label can be applied to versions from
different version histories.
For certain methods, if the request-URL identifies a version-
controlled resource, a label can be specified in a Label request
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header (see Section 8.3) to cause the method to be applied to the
version selected by that label from the version history of that
version-controlled resource.
8.1 Additional Version Properties
The label feature introduces the following REQUIRED property for a
version.
8.1.1 DAV:label-name-set (protected)
This property contains the labels that currently select this
version.
PCDATA value: string
8.2 LABEL Method
A LABEL request can be applied to a version to modify the labels
that select that version. The case of a label name MUST be
preserved when it is stored and retrieved. When comparing two
label names to decide if they match or not, a server SHOULD use a
case-sensitive octet-by-octet comparison of the two label names.
If a LABEL request is applied to a checked in version-controlled
resource, the operation MUST be applied to the DAV:checked-in
version of that version-controlled resource.
Marshalling:
The request body MUST be a DAV:label element.
ANY value: A sequence of elements with at most one DAV:add,
DAV:set, or DAV:remove element.
PCDATA value: string
The request MAY include a Label header.
The request MAY include a Depth header. If no Depth header is
included, Depth:0 is assumed. Standard depth semantics apply, and
the request is applied to the collection identified by the request-
URL and to all members of the collection that satisfy the Depth
value. If a Depth header is included and the request fails on any
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resource, the response MUST be a 207 Multi-Status that identifies
all resources for which the request has failed.
If a response body is included, it MUST be a DAV:label-response XML
element.
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:must-be-checked-in): If the request-URL identifies a version-
controlled resource, the version-controlled resource MUST be
checked in.
(DAV:must-select-version-in-history): If a Label request header is
included and the request-URL identifies a version-controlled
resource, the specified label MUST select a version in the version
history of the version-controlled resource.
(DAV:add-must-be-new-label): If DAV:add is specified in the request
body, the specified label MUST NOT appear in the DAV:label-name-set
of any version in the version history of that version-controlled
resource.
(DAV:label-must-exist): If DAV:remove is specified in the request
body, the specified label MUST appear in the DAV:label-name-set of
that version.
Postconditions:
(DAV:add-or-set-label): If DAV:add or DAV:set is specified in the
request body, the specified label MUST appear in the DAV:label-
name-set of the specified version, and MUST NOT appear in the
DAV:label-name-set of any other version in the version history of
that version.
(DAV:remove-label): If DAV:remove is specified in the request body,
the specified label MUST NOT appear in the DAV:label-name-set of
any version in the version history of that version.
8.2.1 Example - Setting a label
>>REQUEST
LABEL /foo.html HTTP/1.1
Host: www.webdav.org
Content-type: text/xml; charset="utf-8"
Content-Length: xxxx
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default
>>RESPONSE
HTTP/1.1 200 OK
Cache-Control: no-cache
In this example, the label "default" is applied to the DAV:checked-
in version of /foo.html.
8.3 Label Header
For certain methods (e.g. GET, PROPFIND), if the request-URL
identifies a version-controlled resource, a label can be specified
in a Label request header to cause the method to be applied to the
version selected by that label from the version history of that
version-controlled resource.
The value of a label header is the name of a label, encoded using
UTF-8. For example, the label "release-2.0" is identified by the
following header:
Label: release-2.0
A Label header MUST have no effect on a request whose request-URL
does not identify a version-controlled resource. In particular, it
MUST have no effect on a request whose request-URL identifies a
version or a version history.
A server MUST return an HTTP-1.1 Vary header containing Label in a
successful response to a cacheable request (e.g. GET) that includes
a Label header.
8.4 Additional OPTIONS Semantics
If the server supports the label feature, it MUST include "label"
as a field in the DAV response header from an OPTIONS request on
any resource that supports any versioning properties, reports, or
methods.
8.5 Additional GET Semantics
Additional Marshalling:
The request MAY include a Label header.
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Additional Preconditions:
(DAV:must-select-version-in-history): If a Label request header is
included and the request-URL identifies a version-controlled
resource, the specified label MUST select a version in the version
history of the version-controlled resource.
Additional Postconditions:
(DAV:apply-request-to-labeled-version): If the request-URL
identifies a version-controlled resource and a Label request header
is included, the response MUST contain the content of the specified
version rather than that of the version-controlled resource.
8.6 Additional PROPFIND Semantics
Additional Marshalling:
The request MAY include a Label header.
Additional Preconditions:
(DAV:must-select-version-in-history): If a Label request header is
included and the request-URL identifies a version-controlled
resource, the specified label MUST select a version in the version
history of the version-controlled resource.
Additional Postconditions:
(DAV:apply-request-to-labeled-version): If the request-URL
identifies a version-controlled resource and a Label request header
is included, the response MUST contain the properties of the
specified version rather than that of the version-controlled
resource.
8.7 Additional COPY Semantics
Additional Marshalling:
The request MAY include a Label header.
Additional Preconditions:
(DAV:must-select-version-in-history): If a Label request header is
included and the request-URL identifies a version-controlled
resource, the specified label MUST select a version in the version
history of the version-controlled resource.
Additional Postconditions:
(DAV:apply-request-to-labeled-version): If the request-URL
identifies a version-controlled resource and a Label request header
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is included, the request MUST have copied the properties and
content of the specified version rather than that of the version-
controlled resource.
8.8 Additional CHECKOUT Semantics
If the server supports the working-resource option, a LABEL header
may be included to check out the version selected by the specified
label.
Additional Marshalling:
The request MAY include a Label header.
Additional Preconditions:
(DAV:must-select-version-in-history): If a Label request header is
included and the request-URL identifies a version-controlled
resource, the specified label MUST select a version in the version
history of the version-controlled resource.
(DAV:must-not-have-label-and-apply-to-version): If a Label request
header is included, the request body MUST NOT contain a DAV:apply-
to-version element.
Additional Postconditions:
(DAV:apply-request-to-labeled-version): If the request-URL
identifies a checked-in version-controlled resource, and a Label
request header is included, the CHECKOUT MUST have been applied to
the version selected by the specified label, and not to the
version-controlled resource itself.
8.9 Additional UPDATE Semantics
If the request body of an UPDATE request contains a DAV:label-name
element, the update target is the resource identified by the
request-URL, and the update source is the version selected by the
specified label from the version history of the update target.
Additional Marshalling:
ANY value: A sequence of elements with at most one DAV:label-name
or DAV:version element (but not both).
PCDATA value: string
The request MAY include a Depth header. If no Depth header is
included, Depth:0 is assumed. Standard depth semantics apply, and
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the request is applied to the collection identified by the request-
URL and to all members of the collection that satisfy the Depth
value. If a Depth header is included and the request fails on any
resource, the response MUST be a 207 Multi-Status that identifies
all resources for which the request has failed.
Additional Preconditions:
(DAV:must-select-version-in-history): If the request includes a
DAV:label-name element in the request body, the label MUST select a
version in the version history of the version-controlled resource
identified by the request-URL.
(DAV:depth-update): If the request includes a Depth header,
standard depth semantics apply, and the request is applied to the
collection identified by the request-URL and to all members of the
collection that satisfy the Depth value. The request MUST be
applied to a collection before being applied to any members of that
collection, since an update of a version-controlled collection
might change the membership of that collection.
Additional Postconditions:
(DAV:apply-request-to-labeled-version): If a DAV:label-name element
appears in the request body, the content and dead properties of the
version-controlled resource must have been updated to be those of
the version selected by that label.
9 WORKING-RESOURCE FEATURE
The working-resource feature provides an alternative to the
workspace feature for supporting parallel development. Unlike the
workspace feature, where the desired configuration of versions and
checked-out resources is maintained on the server, the working-
resource feature maintains the configuration on the client. This
simplifies the server implementation, but does not allow a user to
access the configuration from clients in different physical
locations, such as from another office, from home, or while
traveling. Another difference is that the workspace feature
isolates clients from a logical change that involves renaming
shared resources, until that logical change is complete and tested;
with the working resource feature, all clients use a common set of
shared version-controlled resources and every client sees the
result of a MOVE as soon as it occurs.
If a server supports the working-resource feature but not the
checkout-in-place feature, a CHECKOUT request can only be used to
create a working resource, and cannot be used to check out a
version-controlled resource. If a server supports the checkout-in-
place feature, but not the working-resource feature, a CHECKOUT can
only be used to change the state of a version-controlled resource
from checked-in to checked-out.
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9.1 Additional Version Properties
The working-resource feature introduces the following REQUIRED
properties for a version.
9.1.1 DAV:checkout-fork
This property is defined in Section 4.1.1.
9.1.2 DAV:checkin-fork
This property is defined in Section 4.1.2.
9.2 Working Resource Properties
The working-resource feature introduces the following REQUIRED
properties for a working resource. Since a working resource is
a checked-out resource, it also has any property defined in
this document for a checked-out resource.
9.2.1 DAV:auto-update (protected)
This property identifies the version-controlled resource that will
be updated when the working resource is checked in.
9.2.2 DAV:checkout-fork
This property is defined in Section 4.2.1.
9.2.3 DAV:checkin-fork
This property is defined in Section 4.2.2.
9.3 CHECKOUT Method (applied to a version)
A CHECKOUT request can be applied to a version to create a new
working resource. The content and dead properties of the working
resource are a copy of the version that was checked out.
Marshalling:
If a request body is included, it MUST be a DAV:checkout XML
element.
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ANY value: A sequence of elements with at most one DAV:apply-to-
version and at most one DAV:fork-ok element.
If a response body is included, it MUST be a DAV:checkout-response
XML element.
The response MUST include a Location header.
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:checkout-of-version-with-descendant-is-forbidden): See Section
4.3.
(DAV:checkout-of-version-with-descendant-is-discouraged): See
Section 4.3.
(DAV:checkout-of-checked-out-version-is-forbidden): See Section
4.3.
(DAV:checkout-of-checked-out-version-is-discouraged): See Section
4.3.
Postconditions:
(DAV:create-working-resource): If the request-URL identified a
version, the Location response header MUST contain the URL of a new
working resource. The DAV:checked-out property of the new working
resource MUST identify the version that was checked out. The
content and dead properties of the working resource MUST be copies
of the content and dead properties of the DAV:checked-out version.
The DAV:predecessor-set property of the working resource MUST be
initialized to be the version identified by the request-URL. The
DAV:auto-update property of the working resource MUST NOT exist.
(DAV:create-working-resource-from-checked-in-version): If the
request-URL identified a version-controlled resource, and
DAV:apply-to-version is specified in the request body, the CHECKOUT
is applied to the DAV:checked-in version of the version-controlled
resource, and not the version-controlled resource itself. A new
working resource is created and the version-controlled resource
remains checked-in. The DAV:auto-update property of the working
resource MUST identify the version-controlled resource.
9.3.1 Example - CHECKOUT of a version
>>REQUEST
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CHECKOUT /his/12/ver/V3 HTTP/1.1
Host: repo.webdav.org
Content-Length: 0
>>RESPONSE
HTTP/1.1 201 Created
Location: http://repo.webdav.org/wr/157
Cache-Control: no-cache
In this example, the version identified by
http://repo.webdav.org/his/12/ver/V3 is checked out, and the new
working resource is located at http://repo.webdav.org/wr/157.
9.4 CHECKIN Method (applied to a working resource)
A CHECKIN request can be applied to a working resource to produce a
new version whose content and dead properties are a copy of those
of the working resource. If the DAV:auto-update property of the
working resource was set because the working resource was created
by applying a CHECKOUT with the DAV:apply-to-version flag to a
version-controlled resource, the CHECKIN request will also update
the content and dead properties of that version-controlled resource
to be those of the new version.
Marshalling:
If a request body is included, it MUST be a DAV:checkin XML
element.
ANY value: A sequence of elements with at most one DAV:fork-ok
element.
If a response body is included, it MUST be a DAV:checkin-response
XML element.
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:must-be-checked-out): See Section 4.4.
(DAV:version-history-is-tree) See Section 4.4.
(DAV:checkin-fork-forbidden): See Section 4.4.
(DAV:checkin-fork-discouraged): See Section 4.4.
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(DAV:no-overwrite-by-auto-update): If the DAV:auto-update property
for the checked-out resource identifies a version-controlled
resource, at least one of the versions identified by the
DAV:predecessor-set property of the checked-out resource MUST
identify a version that is either the same as or a descendant of
the version identified by the DAV:checked-in property of that
version-controlled resource.
Postconditions:
(DAV:create-version): See Section 4.4.
(DAV:initialize-version-content-and-properties): See Section 4.4.
(DAV:auto-update): If the DAV:auto-update property of the checked-
out resource identified a version-controlled resource, an UPDATE
request with the new version MUST have been applied to that
version-controlled resource.
(DAV:delete-working-resource): If the request-URL identifies a
working resource and if DAV:keep-checked-out is not specified in
the request body, the working resource is deleted.
9.4.1 Example - CHECKIN of a working resource
>>REQUEST
CHECKIN /wr/157 HTTP/1.1
Host: repo.webdav.org
Content-Length: 0
>>RESPONSE
HTTP/1.1 201 Created
Location: http://repo.webdav.org/his/23/ver/15
Cache-Control: no-cache
In this example, the working resource /wr/157 checked in, and a new
version is created at http://repo.webdav.org/his/23/ver/15.
9.5 Additional OPTIONS Semantics
If the server supports the working-resource feature, it MUST
include "working-resource" as a field in the DAV response header
from an OPTIONS request on any resource that supports any
versioning properties, reports, or methods.
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9.6 Additional COPY Semantics
Additional Postconditions:
(DAV:copy-creates-new-resource): The result of copying a working
resource is a new non-version-controlled resource at the
destination of the COPY. The new resource MAY automatically be put
under version control, but the resulting version-controlled
resource MUST be associated with a new version history created for
that new version-controlled resource.
9.7 Additional MOVE Semantics
Additional Preconditions:
(DAV:cannot-rename-working-resource): If the request-URL identifies
a working resource, the request MUST fail.
Additional Postconditions:
(DAV:update-auto-update): If the request-URL identified a version-
controlled resource, any DAV:auto-update properties that identified
that version-controlled resource MUST have been updated to contain
the new location of that version-controlled resource.
10 ADVANCED VERSIONING FEATURES
Advanced versioning addresses the problems of parallel development
and configuration management of multiple sets of interrelated
resources. Traditionally, artifacts of software development,
including requirements, design documents, code, and test cases,
have been a focus of configuration management. Web sites,
comprising multiple inter-linked resources (HTML, graphics, sound,
CGI, and others), are another class of complex information
artifacts that benefit from the application of configuration
management. The advanced versioning capabilities for coordinating
concurrent change provide the infrastructure for efficient and
controlled management of large evolving web sites.
10.1 Advanced Versioning Packages
Although a server MAY support any combination of advanced
versioning features, in order to minimize the complexity of a
WebDAV advanced versioning client, a WebDAV advanced versioning
server SHOULD support one of the following packages:
Advanced-Server-Workspace Package: basic-server-workspace package
plus all advanced features
Advanced-Client-Workspace Package: basic-client-workspace package
plus all advanced features
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The advanced-server-workspace package supports advanced versioning
capabilities for a client with no persistent state. The advanced-
client-workspace package supports advanced versioning capabilities
for a client that maintains configuration state on the client. A
server that supports both advanced workspace packages will
interoperate with all versioning clients.
10.2 Advanced Versioning Terms
The following additional terms are used by the advanced versioning
features.
Collection
A "collection" is a resource whose state consists of not only
content and properties, but also a set of named "bindings", where a
binding identifies what RFC 2518 calls an "internal member" of the
collection. Note that a binding is not a resource, but rather is a
part of the state of a collection that defines a mapping from a
binding name (a URL segment) to a resource (an internal member of
the collection).
Collection Version Resource
A "collection version resource", or simply "collection version",
captures the dead properties of a version-controlled collection,
as well as the names of its version-controlled bindings (see
Section 14). A version-controlled binding is a binding to a
version-controlled resource. If the checkout-in-place feature is
supported, a collection version can be created by checking out and
then checking in a version-controlled collection. If the
working-resource feature is supported, a collection version can be
created by checking out a collection version (to create a "working
collection") and then checking in the working collection.
Configuration
A "configuration" is a set of resources that consists of a root
collection and all members (not just internal members) of that root
collection that are not members of another configuration. The root
collection is called the "configuration root", and the members of
this set are called the "members of the configuration". Note that
a collection (which is a single resource) is very different from a
configuration (which is a set of resources).
Baseline Resource
A "baseline resource", or simply "baseline", of a collection is a
version of the configuration that is rooted at that collection (see
Section 12). In particular, a baseline captures the DAV:checked-in
version of every version-controlled member of that configuration.
Note that a collection version (which captures the state of a
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single resource) is very different from a collection baseline
(which captures the state of a set of resources).
Baseline-Controlled Collection
A "baseline-controlled collection" is a collection from which
baselines can be created (see Section 12).
Version-Controlled Configuration Resource
A "version-controlled configuration resource", or simply "version-
controlled configuration", is a special kind of version-controlled
resource that is associated with a baseline-controlled collection,
and is used to create and access baselines of that collection (see
Section 12). When a collection is both version-controlled and
baseline-controlled, a client can create a new version of the
collection by checking out and checking in that collection, and it
can create a new baseline of that collection by checking out and
checking in the version-controlled configuration of that
collection.
Activity Resource
An "activity resource", or simply "activity", is a resource that
selects a set of versions that correspond to a single logical
change, where the versions selected from a given version history
form a single line of descent through that version history (see
Section 13).
11 MERGE FEATURE
When a user wants to accept the changes (new versions) created by
someone else, it is important not just to update the version-
controlled resources in the user's workspace with those new
versions, since this could result in "backing out" changes the user
has made to those version-controlled resources. Instead, the
versions created in another workspace should be "merged" into the
user's version-controlled resources.
The version history of a version-controlled resource provides the
information needed to determine the result of the merge. In
particular, the merge should select whichever version is later in
the line of descent from the root version. In case the versions to
be merged are on different lines of descent (neither version is a
descendant of the other), neither version should be selected, but
instead, a new version should be created that contains the logical
merge of the content and dead properties of those versions. The
MERGE request can be used to check out each version-controlled
resource that requires such a merge, and set the DAV:merge-set
property of each checked-out resource to identify the version to be
merged. The user is responsible for modifying the content and dead
properties of the checked-out resource so that it represents the
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logical merge of that version, and then adding that version to the
DAV:predecessor-set of the checked-out resource.
If the server is capable of automatically performing the merge, it
MAY update the content, dead properties, and DAV:predecessor-set of
the checked-out resource itself. Before checking in the
automatically merged resource, the user is responsible for
verifying that the automatic merge is correct.
11.1 Additional Checked-Out Resource Properties
The merge feature introduces the following REQUIRED properties for
a checked-out resource.
11.1.1 DAV:merge-set
This property identifies each version that is to be merged into
this checked-out resource.
11.1.2 DAV:auto-merge-set
This property identifies each version that the server has merged
into this checked-out resource. The client should confirm that the
merge has been performed correctly before moving a URL from the
DAV:auto-merge-set to the DAV:predecessor-set of a checked-out
resource.
11.2 MERGE Method
The MERGE method performs the logical merge of a specified version
(the "merge source") into a specified version-controlled resource
(the "merge target"). If the merge source is neither an ancestor
nor a descendant of the DAV:checked-in or DAV:checked-out version
of the merge target, the MERGE checks out the merge target (if it
is not already checked out) and adds the URL of the merge source to
the DAV:merge-set of the merge target. It is then the client's
responsibility to update the content and dead properties of the
checked-out merge target so that it reflects the logical merge of
the merge source into the current state of the merge target. The
client indicates that it has completed the update of the merge
target, by deleting the merge source URL from the DAV:merge-set of
the checked-out merge target, and adding it to the DAV:predecessor-
set. As an error check for a client forgetting to complete a
merge, the server MUST fail an attempt to CHECKIN a version-
controlled resource with a non-empty DAV:merge-set.
When a server has the ability to automatically update the content
and dead properties of the merge target to reflect the logical
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merge of the merge source, it may do so unless DAV:no-auto-merge is
specified in the MERGE request body. In order to notify the client
that a merge source has been automatically merged, the MERGE
request MUST add the URL of the auto-merged source to the DAV:auto-
merge-set property of the merge target, and not to the DAV:merge-
set property. The client indicates that it has verified that the
auto-merge is valid, by deleting the merge source URL from the
DAV:auto-merge-set, and adding it to the DAV:predecessor-set.
Multiple merge sources can be specified in a single MERGE request.
The set of merge sources for a MERGE request is determined from the
DAV:source element of the MERGE request body as follows:
- If DAV:source identifies a version, that version is a merge
source.
- If DAV:source identifies a version-controlled resource, the
DAV:checked-in version of that version-controlled resource is a
merge source.
- If DAV:source identifies a collection, the DAV:checked-in version
of each version-controlled resource that is a member of that
collection is a merge source.
The request-URL identifies the set of possible merge targets. If
the request-URL identifies a collection, any member of the
configuration rooted at the request-URL is a possible merge target.
The merge target of a particular merge source is the version-
controlled or checked-out resource whose DAV:checked-in or
DAV:checked-out version is from the same version history as the
merge source. If a merge source has no merge target, that merge
source is ignored.
The response to a MERGE request identifies the resources modified
by the request, so that a client can efficiently update any cached
state it is maintaining.
Marshalling:
The request body MUST be a DAV:merge element.
The set of merge sources is determined by the DAV:source element in
the request body.
ANY value: A sequence of elements with one DAV:source element, at
most one DAV:no-auto-merge element, at most one DAV:no-checkout
element, at most one DAV:prop element, and any legal set of
elements that can occur in a DAV:checkout element.
prop: see RFC 2518, Section 12.11
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The response for a successful request MUST be a 207 Multi-Status,
where the DAV:multistatus XML element in the response body
identifies all resources that have been modified by the request.
multistatus: see RFC 2518, Section 12.9
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:cannot-merge-checked-out-resource): The DAV:source element
MUST NOT identify a checked-out resource. If the DAV:source
element identifies a collection, the collection MUST NOT have a
member that is a checked-out resource.
(DAV:checkout-not-allowed): If DAV:no-checkout is specified in the
request body, it MUST be possible to perform the merge without
checking out any of the merge targets.
All preconditions of the CHECKOUT operation apply to the checkouts
performed by the request.
Postconditions:
(DAV:ancestor-version): If a merge target is a version-controlled or
checked-out resource whose DAV:checked-in version or DAV:checked-out
version is the merge source or is a descendant of the merge source,
the merge target MUST NOT have been modified by the MERGE.
(DAV:descendant-version): If the merge target was a checked-in
version-controlled resource whose DAV:checked-in version was an
ancestor of the merge source, an UPDATE operation MUST have been
applied to the merge target to set its content and dead properties
to be those of the merge source. If the UPDATE method is not
supported, the merge target MUST have been checked out, the content
and dead properties of the merge target MUST have been set to those
of the merge source, and the merge source MUST have been added to
the DAV:auto-merge-set of the merge target. The merge target MUST
appear in a DAV:response XML element in the response body.
(DAV:checked-out-for-merge): If the merge target was a checked-in
version-controlled resource whose DAV:checked-in version was
neither a descendant nor an ancestor of the merge source, a
CHECKOUT MUST have been applied to the merge target. All XML
elements in the DAV:merge XML element that could appear in a
DAV:checkout XML element MUST have been used as arguments to the
CHECKOUT request. The merge target MUST appear in a DAV:response
XML element in the response body.
(DAV:update-merge-set): If the DAV:checked-out version of the merge
target is neither equal to nor a descendant of the merge source,
the merge source MUST be added to either the DAV:merge-set or the
DAV:auto-merge-set of the merge target. The merge target MUST
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appear in a DAV:response XML element in the response body. If a
merge source has been added to the DAV:auto-merge-set, the content
and dead properties of the merge target MUST have been modified by
the server to reflect the result of a logical merge of the merge
source and the merge target. If a merge source has been added to
the DAV:merge-set, the content and dead properties of the merge
target MUST NOT have been modified by the server. If DAV:no-auto-
merge is specified in the request body, the merge source MUST NOT
have been added to the DAV:auto-merge-set.
(DAV:report-properties): If DAV:prop is specified in the request
body, the properties specified in the DAV:prop element MUST be
reported in the DAV:response elements in the response body.
11.2.1 Example - MERGE
>>REQUEST
MERGE /ws/public HTTP/1.1
Host: www.webdav.org
Content-type: text/xml; charset="utf-8"
Content-Length: xxxx
http://www.webdav.org/ws/dev/sally
>>RESPONSE
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
Cache-Control: no-cache
http://www.webdav.org/ws/public/src/parse.c
http://www.webdav.org/ws/public/doc/parse.html
In this example, the DAV:checked-in versions from the workspace
http://www.webdav.org/ws/dev/sally are merged into the version-
controlled resources in the workspace
http://www.webdav.org/ws/public. The resources
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/ws/public/src/parse.c and /ws/public/doc/parse.html were modified
by the request.
11.3 DAV:merge-preview Report
A merge preview describes the changes that would result if the
versions specified by the DAV:source element in the request body
were to be merged into the resource identified by the request-URL
(commonly, a collection).
Marshalling:
The request body MUST be a DAV:merge-preview XML element.
The response body for a successful request MUST be a DAV:merge-
preview-response XML element.
A DAV:update-preview element identifies a merge target whose
DAV:checked-in property would change as a result of the MERGE, and
identifies the merge source for that merge target.
A DAV:conflict-preview element identifies a merge target that
requires a merge.
A DAV:common-ancestor element identifies the version that is a
common ancestor of both the merge source and the DAV:checked-in or
DAV:checked-out version of the merge target.
A DAV:ignore-preview element identifies a version that has no
merge target and therefore would be ignored by the merge.
11.3.1 Example - DAV:merge-preview Report
>>REQUEST
REPORT /ws/public HTTP/1.1
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Host: www.webdav.org
Content-type: text/xml; charset="utf-8"
Content-Length: xxxx
http://www.webdav.org/ws/dev/fred
>>RESPONSE
HTTP/1.1 200 OK
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://www.webdav.org/ws/public/foo.html
http://repo.webdav.org/his/23/ver/18
http://repo.webdav.org/his/23/ver/42
http://www.webdav.org/ws/public/bar.html
http://www.repo/his/42/ver/3
In this example, the merge preview report indicates that version
/his/23/ver/42 would be merged in /ws/public/foo.html, and version
/his/42/ver/3 would update /ws/public/bar.html if the workspace
http://www.webdav.org/ws/dev/fred was merged into the workspace
http://www.webdav.org/ws/public.
11.4 Additional OPTIONS Semantics
If the server supports the merge feature, it MUST include "merge"
as a field in the DAV response header from an OPTIONS request on
any resource that supports any versioning properties, reports, or
methods.
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11.5 Additional DELETE Semantics
Additional Postconditions:
(DAV:delete-version-reference): If a version is deleted, any
reference to that version in a DAV:merge-set or DAV:auto-merge-set
property MUST be removed.
11.6 Additional CHECKIN Semantics
Additional Preconditions:
(DAV:merge-must-be-complete): The DAV:merge-set and DAV:auto-merge-
set of the checked-out resource MUST be empty or not exist.
12 BASELINE FEATURE
A configuration is a set of resources that consists of a root
collection and all members of that root collection that are not
members of another configuration. A configuration that contains a
large number of resources can consume a large amount of space on a
server. This can make it prohibitively expensive to remember the
state of an existing configuration by creating a Depth:infinity
copy of its root collection.
A baseline is a version resource that captures the state of each
version-controlled member of a configuration. A baseline history
is a version history whose versions are baselines. New baselines
are created by checking out and then checking in a special kind of
version-controlled resource called a version-controlled
configuration.
A collection that is under baseline control is called a baseline-
controlled collection. In order to allow efficient baseline
implementation, the state of a baseline of a collection is limited
to be a set of versions and their names relative to the collection,
and the operations on a baseline are limited to the creation of a
baseline from a collection, and restoring or merging the baseline
back into a collection. A server MAY automatically put a
collection under baseline control when it is created, or a client
can use the BASELINE-CONTROL method to put a specified collection
under baseline control.
As a configuration gets large, it is often useful to break it up
into a set of smaller configurations that form the logical
"components" of that configuration. In order to capture the fact
that a baseline of a configuration is logically extended by a
component configuration baseline, the component configuration
baseline is captured as a "subbaseline" of the baseline.
The root collection of a configuration is unconstrained with
respect to its relationship to the root collection of any of its
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components. In particular, the root collection of a configuration
can have a member that is the root collection of one of its
components (e.g. configuration /sys/x can have a component
/sys/x/foo), can be a member of the root collection of one of its
components (e.g. configuration /sys/y/z can have a component
/sys/y), or neither (e.g. configuration /sys/x can have a component
/comp/bar).
12.1 Version-Controlled Configuration Properties
Since a version-controlled configuration is a version-controlled
resource, it has all the properties of a version-controlled
resource. In addition, the baseline feature introduces the
following REQUIRED property for a version-controlled configuration.
12.1.1 DAV:baseline-controlled-collection (protected)
This property identifies the collection that contains the version-
controlled resources whose DAV:checked-in versions are being
tracked by this version-controlled configuration. The DAV:version-
controlled-configuration of the DAV:baseline-controlled-collection
of a version-controlled configuration MUST identify that version-
controlled configuration.
12.2 Checked-Out Configuration Properties
Since a checked-out configuration is a checked-out resource, it has
all the properties of a checked-out resource. In addition, the
baseline feature introduces the following REQUIRED property for a
checked-out configuration.
12.2.1 DAV:subbaseline-set
This property determines the DAV:subbaseline-set property of the
baseline that results from checking in this resource.
A server MAY reject attempts to modify the DAV:subbaseline-set of a
checked-out configuration.
12.3 Baseline Properties
The DAV:resourcetype of a baseline MUST be DAV:baseline. Since a
baseline is a version resource, it has all the properties of a
version resource. In addition, the baseline feature introduces the
following REQUIRED properties for a baseline.
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12.3.1 DAV:baseline-collection (protected)
This property contains a server-defined URL for a collection of
checked-in version-controlled resources, where each member of this
collection has the same DAV:checked-in version and relative name as
a member of the baseline-controlled collection at the time the
baseline was created. At most one member of this collection can
have a DAV:checked-in version from a given version history.
12.3.2 DAV:subbaseline-set (protected)
The URLs in the DAV:subbaseline-set property MUST identify a set of
other baselines. The subbaselines of a baseline are the baselines
identified by its DAV:subbaseline-set and all subbaselines of the
baselines identified by its DAV:subbaseline-set.
12.4 Additional Resource Properties
The baseline feature introduces the following REQUIRED property for
a resource.
12.4.1 DAV:version-controlled-configuration (computed)
If the resource is a member of a version-controlled configuration
(i.e. the resource is a collection under baseline control or is a
member of a collection under baseline control), this property
identifies that version-controlled configuration.
12.5 Additional Workspace Properties
The baseline feature introduces the following REQUIRED property for
a workspace.
12.5.1 DAV:baseline-controlled-collection-set (computed)
This property identifies each member of the workspace that is a
collection under baseline control (as well as the workspace itself,
if it is under baseline control).
12.6 BASELINE-CONTROL Method
A collection can be placed under baseline control with a BASELINE-
CONTROL request. When a collection is placed under baseline
control, the DAV:version-controlled-configuration property of the
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collection is set to identify a new version-controlled
configuration. This version-controlled configuration can be
checked out and then checked in to create a new baseline for that
collection.
If a baseline is specified in the request body, the DAV:checked-in
version of the new version-controlled configuration will be that
baseline, and the collection is initialized to contain version-
controlled members whose DAV:checked-in versions and relative names
are determined by the specified baseline.
If no baseline is specified, a new baseline history is created
containing a baseline that captures the state of the version-
controlled members of the collection, and the DAV:checked-in
version of the version-controlled configuration will be that
baseline.
Marshalling:
If a request body is included, it MUST be a DAV:baseline-control
XML element.
ANY value: A sequence of elements with at most one DAV:baseline
element.
If a response body is included, it MUST be a DAV:baseline-control-
response XML element.
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:version-controlled-configuration-must-not-exist): The
DAV:version-controlled-configuration property of the collection
identified by the request-URL MUST not exist.
(DAV:must-be-baseline): The DAV:href of the DAV:baseline element in
the request body MUST identify a baseline.
(DAV:must-have-no-version-controlled-members): If a DAV:baseline
element is specified in the request body, the collection identified
by the request-URL MUST have no version-controlled members.
(DAV:one-baseline-controlled-collection-per-history-per-workspace):
If the request-URL identifies a workspace or a member of a
workspace, and if a baseline is specified in a DAV:baseline element
in the request body, then there MUST NOT be another collection in
that workspace whose DAV:version-controlled-configuration property
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identifies a version-controlled configuration for the baseline
history of that baseline.
Postconditions:
(DAV:create-version-controlled-configuration): A new version-
controlled configuration is created, whose DAV:baseline-controlled-
collection property identifies the collection.
(DAV:reference-version-controlled-configuration): The DAV:version-
controlled-configuration of the collection identifies the new
version-controlled configuration.
(DAV:select-existing-baseline): If the request body specifies a
baseline, the DAV:checked-in property of the new version-controlled
configuration MUST have been set to identify this baseline. A
version-controlled member of the collection will be created for
each version in the baseline, where the version-controlled member
will have the content and dead properties of that version, and will
have the same name relative to the collection as the corresponding
version-controlled resource had when the baseline was created. Any
nested collections that are needed to provide the appropriate name
for a version-controlled member will be created.
(DAV:create-new-baseline): If no baseline is specified in the
request body, the request MUST have created a new baseline history
at a server-defined URL, and MUST have created a new baseline in
that baseline history. The DAV:baseline-collection of the new
baseline MUST identify a collection whose members have the same
relative name and DAV:checked-in version as the version-controlled
members of the request collection. The DAV:checked-in property of
the new version-controlled configuration MUST identify the new
baseline.
12.6.1 Example - BASELINE-CONTROL
>>REQUEST
BASELINE-CONTROL /src HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://www.webdav.org/repo/blh/13/ver/8
>>RESPONSE
HTTP/1.1 200 OK
Cache-Control: no-cache
Content-Length: 0
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In this example, the collection /src is placed under baseline
control, and is populated with members from an existing baseline.
A new version-controlled configuration (/repo/vcc/128) is created
and associated with /src, and /src is initialized with version-
controlled members whose DAV:checked-in versions are those selected
by the DAV:baseline-collection (/repo/bc/15) of the specified
baseline (/repo/blh/13/ver/8). The following diagram illustrates
the resulting state on the server.
+-------------------------------------+
|Baseline-Controlled Collection |<------+
|/src | |
|-------------------------------------| |
|DAV:version-controlled-configuration +---+ |
+-------------------------------------+ | |
| |
| |
+-------------------------------------+ | |
|Version-Controlled Configuration |<--+ |
|/repo/vcc/128 | |
|-------------------------------------| |
|DAV:baseline-controlled-collection +-------+
|-------------------------------------|
|DAV:checked-in +-------+
+-------------------------------------+ |
|DAV:version-history +---+ |
+-------------------------------------+ | |
| |
| |
+------------------------+ | |
|Baseline History |<---------------+ |
|/repo/blh/13 | |
|------------------------+ |
|DAV:version-set +----------------+ |
+------------------------+ | | | | |
v | v v |
| |
+------------------------+ | |
|Baseline |<-------+-----------+
|/repo/blh/13/ver/8 |
|------------------------+ +--------------+
|DAV:baseline-collection +---->|Collection |
+------------------------+ |/repo/bc/15 |
+--------------+
In order to create new baselines of /src, /repo/vcc/128 can be
checked out, new versions can be created or selected by the
version-controlled members of /src, and then /repo/vcc/128 can be
checked in to capture the current state of those version-controlled
members.
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12.7 DAV:compare-baseline Report
A DAV:compare-baseline report contains the differences between the
baseline identified by the request-URL (the "request baseline") and
the baseline specified in the request body (the "compare
baseline").
Marshalling:
The request body MUST be a DAV:compare-baseline XML element.
The response body for a successful request MUST be a DAV:compare-
baseline-report XML element.
A DAV:added-version element identifies a version that is the
DAV:checked-in version of a member of the DAV:baseline-collection
of the compare baseline, but no version in the version history of
that version is the DAV:checked-in version of a member of the
DAV:baseline-collection of the request baseline.
A DAV:deleted-version element identifies a version that is the
DAV:checked-in version of a member of the DAV:baseline-collection
of the request baseline, but no version in the version history of
that version is the DAV:checked-in version of a member of the
DAV:baseline-collection of the compare baseline.
A DAV:changed-version element identifies two different versions
from the same version history that are the DAV:checked-in version
of the DAV:baseline-collection of the request baseline and the
compare baseline, respectively.
Preconditions:
(DAV:must-be-baseline): The DAV:href in the request body MUST
identify a baseline.
(DAV:baselines-from-same-history): A server MAY require that the
baselines being compared be from the same baseline history.
12.7.1 Example - DAV:compare-baseline Report
>>REQUEST
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REPORT /bl-his/12/bl/14 HTTP/1.1
Host: repo.webdav.com
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://repo.webdav.org/bl-his/12/bl/15
>>RESPONSE
HTTP/1.1 200 OK
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://repo.webdav.org/his/23/ver/8
http://repo.webdav.org/his/29/ver/12
http://repo.webdav.org/his/29/ver/19
http://repo.webdav.org/his/12/ver/4
In this example, the differences between baseline 14 and baseline
15 of http://repo.webdav.org/bl-his/12 are identified.
12.8 Additional OPTIONS Semantics
If a server supports the baseline feature, it MUST include
"baseline" as a field in the DAV response header from an OPTIONS
request on any resource that supports any versioning properties,
reports, or methods.
12.9 Additional MKCOL Semantics
Additional Postconditions:
If a server automatically puts a newly created collection under
baseline control, all postconditions for BASELINE-CONTROL apply to
the MKCOL.
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12.10 Additional COPY Semantics
Additional Postconditions:
If the request creates a new collection at the Destination, and a
server automatically puts a newly created collection under baseline
control, all postconditions for BASELINE-CONTROL apply to the COPY.
12.11 Additional CHECKOUT Semantics
Additional Preconditions:
(DAV:must-not-update-baseline-collection): If the request-URL
identifies a member of the configuration rooted at the
DAV:baseline-collection of a baseline, the request MUST fail.
12.12 Additional CHECKIN Semantics
Additional Preconditions:
(DAV:no-checked-out-baseline-controlled-collection-members): If the
request-URL identifies a version-controlled configuration, all
version-controlled members of the DAV:baseline-controlled-
collection of the version-controlled configuration MUST be checked-
in.
(DAV:one-version-per-history-per-baseline): If the request-URL
identifies a version-controlled configuration, the set of versions
selected by that version-controlled configuration MUST contain at
most one version from any version history, where a version is
selected by a version-controlled configuration if the version is
identified by the DAV:checked-in property of any member of the
configuration rooted at the DAV:baseline-controlled collection of
that version-controlled configuration, or is identified by the
DAV:checked-in property of any member of the configuration rooted
at the DAV:baseline-collection of any subbaseline of that version-
controlled configuration.
(DAV:cannot-modify-version-controlled-configuration): If the
request-URL identifies a version-controlled member of a baseline-
controlled collection whose version-controlled configuration is
checked-in, the request MUST fail unless the DAV:auto-version
property of the version-controlled configuration will automatically
check out that version-controlled configuration when it is
modified.
Additional Postconditions:
(DAV:create-baseline-collection): If the request-URL identifies a
version-controlled configuration, the DAV:baseline-collection of
the new baseline identifies a collection whose members have the
same relative name and DAV:checked-in version as the members of the
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DAV:baseline-controlled-collection of the version-controlled
configuration at the time of the request.
(DAV:modify-configuration): If the request-URL identifies a
version-controlled member of a baseline-controlled collection, this
is a modification to the version-controlled configuration of that
baseline-controlled collection, and standard auto-versioning
semantics apply.
12.13 Additional UPDATE Semantics
Additional Preconditions:
(DAV:baseline-controlled-members-must-be-checked-in): If the
request-URL identifies a version-controlled configuration, then all
version-controlled members of the DAV:baseline-controlled-
collection of that version-controlled configuration MUST be
checked-in.
(DAV:must-not-update-baseline-collection): If the request-URL
identifies a member of the configuration rooted at the
DAV:baseline-collection of a baseline, the request MUST fail.
(DAV:cannot-modify-version-controlled-configuration): If the
request updates the DAV:checked-in property of any version-
controlled member of a baseline-controlled collection whose
version-controlled configuration is checked-in, the request MUST
fail unless the DAV:auto-version property of the version-controlled
configuration will automatically check out that version-controlled
configuration when it is modified.
Additional Postconditions:
(DAV:set-baseline-controlled-collection-members): If the request
updated the DAV:checked-in property of a version-controlled
configuration, then the version-controlled members of the
DAV:baseline-controlled-collection of that version-controlled
configuration MUST have been updated so that they have the same
relative name, content, and dead properties as the members of the
DAV:baseline-collection of the baseline. In particular:
- A version-controlled member for a given version history MUST have
been deleted if there is no version-controlled member for that
version history in the DAV:baseline-collection of the baseline.
- A version-controlled member for a given version history MUST have
been renamed if its name relative to the baseline-controlled
collection is different from that of the version-controlled member
for that version history in the DAV:baseline-collection of the
baseline.
- A new version-controlled member MUST have been created for each
member of the DAV:baseline-collection of the baseline for which
there is no corresponding version-controlled member in the
baseline-controlled collection.
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- An UPDATE request MUST have been applied to each version-
controlled member for a given version history whose DAV:checked-in
version is not the same as that of the version-controlled member
for that version history in the DAV:baseline-collection of the
baseline.
(DAV:update-subbaselines): If the request updated a version-
controlled configuration whose DAV:baseline-controlled-collection
contains a baseline-controlled member for one of the subbaselines
of the request baseline, then the DAV:checked-in property of the
version-controlled configuration of that baseline-controlled member
MUST have been updated to be that subbaseline. If the request
updated a version-controlled configuration whose DAV:baseline-
controlled-collection is a member of a workspace that contains a
baseline-controlled member for one of the subbaselines of the
request baseline, then the DAV:checked-in property of the version-
controlled configuration of that baseline-controlled member MUST
have been updated to be that subbaseline.
(DAV:modify-configuration): If the request updated the DAV:checked-
in property of any version-controlled member of a baseline-
controlled collection, and if this DAV:checked-in property differs
from the DAV:checked-in property of the corresponding version-
controlled member of the DAV:baseline-collection of the
DAV:checked-in baseline of the DAV:version-controlled-configuration
of the baseline-controlled collection, then this is a modification
to that version-controlled configuration, and standard auto-
versioning semantics apply.
12.14 Additional MERGE Semantics
If the merge source is a baseline, the merge target is a version-
controlled configuration for the baseline history of that baseline,
where the baseline-controlled collection of that version-controlled
configuration is a member of the collection identified by the
request-URL.
Additional Preconditions:
(DAV:must-not-update-baseline-collection): Same semantics as UPDATE
(see Section 12.13).
(DAV:cannot-modify-version-controlled-configuration): Same
semantics as UPDATE (see Section 12.13).
Additional Postconditions:
(DAV:merge-baseline): If the merge target is a version-controlled
configuration whose DAV:checked-out baseline is not a descendant of
the merge baseline, then the merge baseline MUST have been added to
the DAV:auto-merge-set of a version-controlled configuration. The
DAV:checked-in version of each member of the DAV:baseline-
collection of that baseline MUST have been merged into the
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DAV:baseline-controlled-collection of that version-controlled
configuration.
(DAV:merge-subbaselines): If the merge target is a version-
controlled configuration whose DAV:baseline-controlled-collection
contains a baseline-controlled member for one of the subbaselines
of the merge baseline, then that subbaseline MUST have been merged
into the version-controlled configuration of that baseline-
controlled member. If the merge target is a version-controlled
configuration whose DAV:baseline-controlled-collection is a member
of a workspace that contains a baseline-controlled member for one
of the subbaselines of the merge baseline, then that subbaseline
MUST have been merged into the version-controlled configuration of
that baseline-controlled member.
(DAV:set-baseline-controlled-collection-members): Same semantics as
UPDATE (see Section 12.13).
(DAV:modify-configuration): Same semantics as UPDATE (see Section
12.13).
13 ACTIVITY FEATURE
An activity is a resource that selects a set of versions that are
on a single "line of descent", where a line of descent is a
sequence of versions connected by successor relationships. If an
activity selects versions from multiple version histories, the
versions selected in each version history must be on a single line
of descent.
A common problem that motivates the use of activities is that it is
often desirable to perform several different logical changes in a
single workspace, and then selectively merge a subset of those
logical changes to other workspaces. An activity can be used to
represent a single logical change, where an activity tracks all the
resources that were modified to effect that single logical change.
When a version-controlled resource is checked out, the user
specifies which activity should be associated with a new version
that will be created when that version-controlled resource is
checked in. It is then possible to select a particular logical
change for merging into another workspace, by specifying the
appropriate activity in a MERGE request.
Another common problem is that although a version-controlled
resource may need to have multiple lines of descent, all work done
by members of a given team must be on a single line of descent (to
avoid merging between team members). An activity resource provides
the mechanism for addressing this problem. When a version-
controlled resource is checked out, a client can request that an
existing activity be used or that a new activity be created.
Activity semantics then ensure that all versions in a given version
history that are associated with an activity are on a single line
of descent. If all members of a team share a common activity (or
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sub-activities of a common activity), then all changes made by
members of that team will be on a single line of descent.
The following diagram illustrates activities. Version V5 is the
latest version of foo.html selected by activity Act-2, and version
V8 is the latest version of bar.html selected by activity Act-2.
foo.html History bar.html History
+---+ +---+
Act-1| |V1 Act-1| |V6
+---+ +---+
| |
| |
+---+ +---+
Act-1| |V2 Act-2| |V7
+---+ +---+
/ \ |
/ \ |
+---+ +---+ +---+
Act-1| | Act-2| |V4 Act-2| |V8
+---+ +---+ +---+
| |
| |
+---+ +---+
Act-2| |V5 Act-3| |V9
+---+ +---+
Activities appear under a variety of names in existing versioning
systems. When an activity is used to capture a logical change, it
is commonly called a "change set". When an activity is used to
capture a line of descent, it is commonly called a "branch". When
a system supports both branches and change sets, it is often useful
to require that a particular change set occur on a particular
branch. This relationship can be captured by making the change set
activity be a "subactivity" of the branch activity.
13.1 Activity Properties
The DAV:resourcetype of an activity MUST be DAV:activity.
The activity feature introduces the following REQUIRED properties
for an activity.
13.1.1 DAV:activity-version-set (computed)
This property identifies each version whose DAV:activity-set
property identifies this activity. Multiple versions of a single
version history can be selected by an activity's DAV:activity-
version-set property, but all DAV:activity-version-set versions
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from a given version history must be on a single line of descent
from the root version of that version history.
13.1.2 DAV:activity-checkout-set (computed)
This property identifies each checked-out resource whose
DAV:activity-set identifies this activity.
13.1.3 DAV:subactivity-set
This property identifies each activity that forms a part of the
logical change being captured by this activity. An activity
behaves as if its DAV:activity-version-set is extended by the
DAV:activity-version-set of each activity identified in the
DAV:subactivity-set. In particular, the versions in this extended
set MUST be on a single line of descent, and when an activity
selects a version for merging, the latest version in this extended
set is the one that will be merged.
A server MAY reject attempts to modify the DAV:subactivity-set of
an activity.
13.1.4 DAV:current-workspace-set (computed)
This property identifies each workspace whose DAV:current-activity-
set identifies this activity.
13.2 Additional Version Properties
The activity feature introduces the following REQUIRED property for
a version.
13.2.1 DAV:activity-set
This property identifies the activities that determine to which
logical changes this version contributes, and on which lines of
descent this version appears. A server MAY restrict the
DAV:activity-set to identify a single activity. A server MAY
refuse to allow the value of the DAV:activity-set property of a
version to be modified.
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13.3 Additional Checked-Out Resource Properties
The activity feature introduces the following REQUIRED properties
for a checked-out resource.
13.3.1 DAV:unreserved
This property of a checked-out resource indicates whether the
DAV:activity-set of another checked-out resource associated with
the version history of this version-controlled resource can have an
activity that is in the DAV:activity-set property of this checked-
out resource.
A result of the requirement that an activity must form a single
line of descent through a given version history is that if multiple
checked-out resources for a given version history are checked out
unreserved into a single activity, only the first CHECKIN will
succeed. Before another of these checked-out resources can be
checked in, the user will first have to merge into that checked-out
resource the latest version selected by that activity from that
version history, and then modify the DAV:predecessor-set of that
checked-out resource to identify that version.
PCDATA value: boolean
13.3.2 DAV:activity-set
This property of a checked-out resource determines the
DAV:activity-set property of the version that results from checking
in this resource.
13.4 Additional Workspace Properties
The activity feature introduces the following REQUIRED property for
a workspace.
13.4.1 DAV:current-activity-set
This property identifies the activities that currently are being
performed in this workspace. When a member of this workspace is
checked out, if no activity is specified in the checkout request,
the DAV:current-activity-set will be used. This allows an
activity-unaware client to update a workspace in which activity
tracking is required. The DAV:current-activity-set MAY be
restricted to identify at most one activity.
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13.5 MKACTIVITY Method
A MKACTIVITY request creates a new activity resource. A server MAY
restrict activity creation to particular collections, but a client
can determine the location of these collections from a
DAV:activity-collection-set OPTIONS request.
Marshalling:
If a request body is included, it MUST be a DAV:mkactivity XML
element.
If a response body is included, it MUST be a DAV:mkactivity-
response XML element.
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:resource-must-be-null): A resource MUST NOT exist at the
request-URL.
(DAV:activity-location-ok): The request-URL MUST identify a
location where an activity can be created.
Postconditions:
(DAV:initialize-activity): A new activity exists at the request-
URL. The DAV:resourcetype of the activity MUST be DAV:activity.
13.5.1 Example - MKACTIVITY
>>REQUEST
MKACTIVITY /act/test-23 HTTP/1.1
Host: repo.webdav.org
Content-Length: 0
>>RESPONSE
HTTP/1.1 201 Created
Cache-Control: no-cache
In this example, a new activity is created at
http://repo.webdav.org/act/test-23.
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13.6 DAV:latest-activity-version Report
The DAV:latest-activity-version report can be applied to a version
history to identify the latest version that is selected from that
version history by a given activity.
Marshalling:
The request body MUST be a DAV:latest-activity-version XML element.
The response body for a successful request MUST be a DAV:latest-
activity-version-report XML element.
The DAV:href of the response body MUST identify the version of the
given version history that is a member of the DAV:activity-version-
set of the given activity and has no descendant that is a member of
the DAV:activity-version-set of that activity.
Preconditions:
(DAV:must-be-activity): The DAV:href in the request body MUST
identify an activity.
13.7 Additional OPTIONS Semantics
If the server supports the activity feature, it MUST include
"activity" as a field in the DAV response header from an OPTIONS
request on any resource that supports any versioning properties,
reports, or methods.
A DAV:activity-collection-set element MAY be included in the
request body to identify collections that may contain activity
resources.
Additional Marshalling:
If an XML request body is included, it MUST be a DAV:options XML
element.
ANY value: A sequence of elements with at most one DAV:activity-
collection-set element.
If an XML response body for a successful request is included, it
MUST be a DAV:options-response XML element.
ANY value: A sequence of elements with at most one DAV:activity-
collection-set element.
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If DAV:activity-collection-set is included in the request body, the
response body for a successful request MUST contain a DAV:activity-
collection-set element identifying collections that may contain
activities. An identified collection MAY be the root collection of
a tree of collections, all of which may contain activities. Since
different servers can control different parts of the URL namespace,
different resources on the same host MAY have different
DAV:activity-collection-set values. The identified collections MAY
be located on different hosts from the resource.
13.8 Additional DELETE Semantics
Additional Postconditions:
(DAV:delete-activity-reference): If an activity is deleted, any
reference to that activity in a DAV:activity-set, DAV:subactivity-
set, or DAV:current-activity-set MUST be removed.
13.9 Additional MOVE Semantics
Additional Postconditions:
(DAV:update-checked-out-reference): If a checked-out resource is
moved, any reference to that resource in a DAV:activity-checkout
property MUST be updated to refer to the new location of that
resource.
(DAV:update-activity-reference): If the request-URL identifies an
activity, any reference to that activity in a DAV:activity-set,
DAV:subactivity-set, or DAV:current-activity-set MUST be updated
to refer to the new location of that activity.
(DAV:update-workspace-reference): If the request-URL identifies a
workspace, any reference to that workspace in a DAV:current-
workspace-set property MUST be updated to refer to the new location
of that workspace.
13.10 Additional CHECKOUT Semantics
A CHECKOUT request MAY specify the DAV:activity-set for the
checked-out resource.
Additional Marshalling:
ANY value: A sequence of elements with at most one DAV:activity-set
and at most one DAV:unreserved.
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Additional Preconditions:
(DAV:one-checkout-per-activity-per-history): If there is a request
activity set, unless DAV:unreserved is specified, another checkout
from a version of that version history MUST NOT select an activity
in that activity set.
(DAV:linear-activity): If there is a request activity set, unless
DAV:unreserved is specified, the selected version MUST be a
descendant of all other versions of that version history that
select that activity.
Additional Postconditions:
(DAV:initialize-activity-set): The DAV:activity-set of the checked-
out resource is set as follows:
- If DAV:new is specified as the DAV:activity-set in the request
body, then a new activity created by the server is used.
- Otherwise, if activities are specified in the request body, then
those activities are used.
- Otherwise, if the version-controlled resource is a member of a
workspace and the DAV:current-activity-set of the workspace is set,
then those activities are used.
- Otherwise, the DAV:activity-set of the DAV:checked-out version is
used.
(DAV:initialize-unreserved): If DAV:unreserved was specified in the
request body, then the DAV:unreserved property of the checked-out
resource MUST be "true".
13.10.1 Example - CHECKOUT with an activity
>>REQUEST
CHECKOUT /ws/public/foo.html HTTP/1.1
Host: www.webdav.org
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://repo.webdav.org/act/fix-bug-23
>>RESPONSE
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HTTP/1.1 200 OK
Cache-Control: no-cache
In this example, the CHECKOUT is being performed in the
http://repo.webdav.org/act/fix-bug-23 activity.
13.11 Additional CHECKIN Semantics
Additional Preconditions:
(DAV:linear-activity): Any version which is in the version history
of the checked-out resource and whose DAV:activity-set identifies
an activity from the DAV:activity-set of the checked-out resource
MUST be an ancestor of the checked-out resource.
Additional Postconditions:
(DAV:initialize-activity-set): The DAV:activity-set of the new
version MUST have been initialized to be the same as the
DAV:activity-set of the checked-out resource.
13.12 Additional MERGE Semantics
If the DAV:source element of the request body identifies an
activity, then all checked-out resources in that activity (or any
subactivity of that activity) are checked in, and then for each
version history containing a version selected by that activity, the
latest version selected by that activity is a merge source. Note
that the versions selected by an activity are the versions in its
DAV:activity-version-set unioned with the versions selected by the
activities in its DAV:subactivity-set.
A checked-out baseline in the activity is checked-in only after all
other checked-out resources have been checked in and merged to
their merge target. This ensures that modifications to members of
a collection are captured by any new baseline of that collection.
If a working baseline is checked in, the baseline-controlled
collection that determines the DAV:baseline-collection of the new
baseline is the merge target of that working baseline.
Additional Preconditions:
(DAV:atomic-activity-checkin): If the DAV:source element identifies
an activity, the server MAY fail the request if any of the checked-
out resources in the DAV:activity-checkout-set of the activity
cannot be checked in.
Additional Postconditions:
(DAV:checkin-activity): If the DAV:source element identified an
activity, before determining the merge sources, the server MUST
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have checked in each checked-out resource that was in the
DAV:activity-checkout-set. Before checking in a checked-out
baseline, the server MUST have already checked in and merged all
checked-out non-baseline resources. If a checked-out baseline was
a working baseline, the baseline-controlled collection that
determined the DAV:baseline-collection for the new baseline MUST
have been the merge target for that new baseline.
14 VERSION-CONTROLLED-COLLECTION FEATURE
As with any versionable resource, when a collection is put under
version control, a version history resource is created to contain
versions for that version-controlled collection. In order to
preserve standard versioning semantics (a version of a collection
should not be modifiable), a collection version only records
information about the version-controlled bindings of that
collection.
In order to cleanly separate a modification to the namespace from a
modification to content or dead properties, a version of a
collection has no members, but instead records in its DAV:version-
controlled-binding-set property the binding name and version
history resource of each version-controlled internal member of that
collection. If, instead, a collection version contained bindings
to other versions, creating a new version of a resource would
require creating a new version of all the collection versions that
contain that resource, which would cause activities to become
entangled. For example, suppose a "feature-12" activity created a
new version of /x/y/a.html. If a collection version contained
bindings to versions of its members, a new version of /x/y would
have to be created to contain the new version of /x/y/a.html, and a
new version of /x would have to be created to contain the new
version of /x/y. Now suppose a "bugfix-47" activity created a new
version of /x/z/b.html. Again, a new version of /x/z and a new
version of /x would have to be created to contain the new version
of /x/y/b.html. But now it is impossible to merge just "bugfix-47"
into another workspace without "feature-12", because the version of
/x that contains the desired version of /x/z/b.html also contains
version of /x/y/a.html created for "feature-12". If, instead, a
collection version just records the binding name and version
history resource of each version-controlled internal member,
changing the version selected by a member of that collection would
not require a new version of the collection. The new version is
still in the same version history so no new collection version is
required, and "feature-12" and "bugfix-47" would not become
entangled.
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In the following example, there are three version histories, named
VH14, VH19, and VH24, where VH14 contains versions of a collection.
The version-controlled collection /x has version V2 of version
history VH14 as its DAV:checked-in version. Since V2 has recorded
two version controlled bindings, one with binding name "a" to
version history VH19, and the other with binding name "b" to
version history VH24, /x MUST have two version-controlled bindings,
one named "a" to a version-controlled resource for history VH19,
and the other named "b" to a version-controlled resource for
history VH24. The version-controlled resource /x/a currently has
V4 of VH19 as its DAV:checked-in version, while /x/b has V8 of VH24
as its DAV:checked-in version.
VH19
+---------+
| +---+ |
| | |V4 |
| +---+ |
| | |
| | |
| +---+ |
| | |V5 |
VH14 | +---+ |
+---------+ | | |
| +---+ | | | |
a +---+ | | |V1 | | +---+ |
---->| |checked-in=V4 | +---+ | a | | |V6 |
/ +---+ | | ------>| +---+ |
/ | | / | +---------+
+---+ | +---+ |
/x | |checked-in=V2 | | |V2 |
+---+ | +---+ | VH24
\ | | \ | b +---------+
\ b +---+ | | ------>| +---+ |
---->| |checked-in=V8 | +---+ | | | |V7 |
+---+ | | |V3 | | +---+ |
| +---+ | | | |
+---------+ | | |
| +---+ |
| | |V8 |
| +---+ |
| | |
| | |
| +---+ |
| | |V9 |
| +---+ |
+---------+
For any request (e.g. DELETE, MOVE, COPY) that modifies a version-
controlled binding of a checked-in version-controlled collection,
the request MUST fail unless the version-controlled collection has
a DAV:auto-version property that will automatically check out the
version-controlled collection when it is modified.
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Although a collection version only records the version-controlled
bindings of a collection, a version-controlled collection MAY
contain both version-controlled and non-version-controlled
bindings. Non-version-controlled bindings are not under version
control, and therefore can be added or deleted without checking out
the version-controlled collection.
Note that a collection version captures only a defined subset of
the state of a collection. In particular, a version of a
collection captures its dead properties and its bindings to
version-controlled resources, but not its live properties or
bindings to non-version-controlled resources.
When a server supports the working-resource feature, a client can
check out a collection version to create a working collection.
Unlike a version-controlled collection, which contains bindings to
version-controlled resources and non-version-controlled resources,
a working collection contains bindings to version history resources
and non-version-controlled resources. In particular, a working
collection is initialized to contain bindings to the version
history resources specified by the DAV:version-controlled-binding-
set of the checked out collection version. The members of a
working collection can then be deleted or moved to another working
collection. Non-version-controlled resources can be added to a
working collection with methods such as PUT, COPY, and MKCOL. When
a working collection is checked in, a VERSION-CONTROL request is
automatically applied to every non-version-controlled member of the
working collection, and each non-version-controlled member is
replaced by its newly created version history. The DAV:version-
controlled-binding-set of the new version resulting from checking
in a working collection contains the binding name and version
history URL for each member of the working collection.
14.1 Version-Controlled Collection Properties
A version-controlled collection has all the properties of a
collection and of a version-controlled resource. In addition, the
version-controlled-collection feature introduces the following
REQUIRED property for a version-controlled collection.
14.1.1 DAV:eclipsed-set (computed)
This property identifies the non-version-controlled internal
members of the collection that currently are eclipsing a version-
controlled internal member of the collection.
PCDATA value: URL segment
An UPDATE or MERGE request can give a version-controlled collection
a version-controlled internal member that has the same name as an
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existing non-version-controlled internal member. In this case, the
non-version-controlled internal member takes precedence and is said
to "eclipse" the new versioned-controlled internal member. If the
non-version-controlled internal member is removed (e.g. by a DELETE
or MOVE), the version-controlled internal member is exposed.
14.2 Collection Version Properties
A collection version has all the properties of a version. In
addition, the version-controlled-collection feature introduces the
following REQUIRED property for a collection version.
14.2.1 DAV:version-controlled-binding-set (protected)
This property captures the name and version-history of each
version-controlled internal member of a collection.
PCDATA value: URL segment
14.3 Additional OPTIONS Semantics
If the server supports the version-controlled-collection feature,
it MUST include "version-controlled-collection" as a field in the
DAV response header from an OPTIONS request on any resource that
supports any versioning properties, reports, or methods.
14.4 Additional DELETE Semantics
Additional Preconditions:
(DAV:cannot-modify-checked-in-parent): If the request-URL
identifies a version-controlled resource, the DELETE MUST fail when
the collection containing the version-controlled resource is a
checked-in version-controlled collection, unless DAV:auto-version
semantics will automatically check out the version-controlled
collection.
14.5 Additional MKCOL Semantics
Additional Preconditions:
If the request creates a new resource that is automatically placed
under version control, all preconditions for VERSION-CONTROL apply
to the request.
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Additional Postconditions:
If the new collection is automatically put under version control,
all postconditions for VERSION-CONTROL apply to the request.
14.6 Additional COPY Semantics
Additional Preconditions:
(DAV:cannot-copy-collection-version): If the source of the request
is a collection version, the request MUST fail.
14.7 Additional MOVE Semantics
Additional Preconditions:
(DAV:cannot-modify-checked-in-parent): If the source of the request
is a version-controlled resource, the request MUST fail when the
collection containing the source is a checked-in version-controlled
collection, unless DAV:auto-version semantics will automatically
check out that version-controlled collection.
(DAV:cannot-modify-destination-checked-in-parent): If the source of
the request is a version-controlled resource, the request MUST fail
when the collection containing the destination is a checked-in
version-controlled collection, unless DAV:auto-version semantics
will automatically check out that version-controlled collection.
14.8 Additional VERSION-CONTROL Semantics
Additional Preconditions:
(DAV:cannot-modify-checked-in-parent): If the parent of the
request-URL is a checked-in version-controlled collection, the
request MUST fail unless DAV:auto-version semantics will
automatically check out that version-controlled collection.
Additional Postconditions:
(DAV:new-version-controlled-collection): If the request body
identified a collection version, the collection at the request-URL
MUST contain a version-controlled internal member for each
DAV:version-controlled-binding specified in the DAV:version-
controlled-binding-set of the collection version, where the name
and DAV:version-history of the internal member MUST be the
DAV:binding-name and the DAV:version-history specified by the
DAV:version-controlled-binding. If the internal member is a
member of a workspace, and there is another member of the workspace
for the same version history, those two members MUST identify the
same version-controlled resource; otherwise, a VERSION-CONTROL
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request with a server selected version of the version history MUST
have been applied to the URL for that internal member.
14.9 Additional CHECKOUT Semantics
Additional Postconditions:
(DAV:initialize-version-history-bindings): If the request has been
applied to a collection version, the new working collection MUST be
initialized to contain a binding to each of the history resources
identified in the DAV:version-controlled-binding-set of that
collection version.
14.10 Additional CHECKIN Semantics
Additional Postconditions:
(DAV:initialize-version-controlled-bindings): If the request-URL
identified a version-controlled collection, then the DAV:version-
controlled-binding-set of the new collection version MUST contain a
DAV:version-controlled-binding that identifies the binding name and
version history for each version-controlled binding of the version-
controlled collection.
(DAV:version-control-working-collection-members): If the request-
URL identified a working collection, a VERSION-CONTROL request MUST
have been automatically applied to every non-version-controlled
member of the working collection, and each non-version-controlled
member MUST have been replaced by its newly created version
history. If a working collection member was a non-version-
controlled collection, every member of the non-version-controlled
collection MUST have been placed under version control before the
non-version-controlled collection was placed under version control.
The DAV:version-controlled-binding-set of the new collection
version MUST contain a DAV:version-controlled-binding that
identifies the binding name and the version history URL for each
member of the working collection.
14.11 Additional UPDATE and MERGE Semantics
Additional Postconditions:
(DAV:update-version-controlled-collection-members): If the request
modified the DAV:checked-in version of a version-controlled
collection, then the version-controlled members of that version-
controlled collection MUST have been updated. In particular:
- A version-controlled internal member MUST have been deleted if
its version history is not identified by the DAV:version-
controlled-binding-set of the new DAV:checked-in version.
- A version-controlled internal member for a given version history
MUST have been renamed if its binding name differs from the
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DAV:binding-name for that version history in the DAV:version-
controlled-binding-set of the new DAV:checked-in version.
- A new version-controlled internal member MUST have been created
when a version history is identified by the DAV:version-controlled-
binding-set of the DAV:checked-in version, but there was no member
of the version-controlled collection for that version history.
If a new version-controlled member is in a workspace that already
has a version-controlled resource for that version history, then
the new version-controlled member MUST be just a binding (i.e.
another name for) that existing version-controlled resource.
Otherwise, the content and dead properties of the new version-
controlled member MUST have been initialized to be those of the
version specified for that version history by the request. If no
version is specified for that version history by the request, the
version selected is server defined.
15 INTERNATIONALIZATION CONSIDERATIONS
This specification has been designed to be compliant with the IETF
Policy on Character Sets and Languages [RFC2277]. Specifically,
where human-readable strings exist in the protocol, either their
charset is explicitly stated, or XML mechanisms are used to specify
the charset used. Additionally, these human-readable strings all
have the ability to express the natural language of the string.
Most of the human-readable strings in this protocol appear in
properties, such as DAV:creator-displayname. As defined by RFC
2518, properties have their values marshaled as XML. XML has
explicit provisions for character set tagging and encoding, and
requires that XML processors read XML elements encoded, at minimum,
using the UTF-8 [RFC2279] encoding of the ISO 10646 multilingual
plane. The charset parameter of the Content-Type header, together
with the XML "encoding" attribute, provide charset identification
information for MIME and XML processors. Proper use of the charset
header with XML is described in RFC 3023. XML also provides a
language tagging capability for specifying the language of the
contents of a particular XML element. XML uses either IANA
registered language tags (see RFC 1766) or ISO 639 language tags in
the "xml:lang" attribute of an XML element to identify the language
of its content and attributes.
DeltaV applications, since they build upon WebDAV, are subject to
the internationalization requirements specified in RFC 2518,
Section 16. In brief, these requirements mandate the use of XML
character set tagging, character set encoding, and language tagging
capabilities. Additionally, they strongly recommend reading RFC
3023 for instruction on the use of MIME media types for XML
transport and the use of the charset header.
Within this specification, a label is a human-readable string that
is marshaled in the Label header and as XML in request entity
bodies. When used in the Label header, the value of the label is
encoded using UTF-8.
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16 SECURITY CONSIDERATIONS
All of the security considerations of WebDAV discussed in RFC 2518,
Section 17 also apply to WebDAV versioning. Some aspects of the
versioning protocol help address security risks introduced by
WebDAV, but other aspects can increase these security risks. These
issues are detailed below.
16.1 Auditing and Traceability
WebDAV increases the ease with which a remote client can modify
resources on a web site, but this also increases the risk of
important information being overwritten and lost, either through
user error or user maliciousness. The use of WebDAV versioning can
help address this problem by guaranteeing that previous information
is saved in the form of immutable versions, and therefore is easily
available for retrieval or restoration. In addition, the version
history provides a log of when changes were made, and by whom.
When requests are appropriately authenticated, the history
mechanism provides a clear audit trail for changes to web
resources. This can often significantly improve the ability to
identify the source of the security problem, and thereby help guard
against it in the future.
16.2 Increased Need for Access Control
WebDAV versioning provides a variety of links between related
pieces of information. This can increase the risk that
authentication or authorization errors allow a client to locate
sensitive information. For example, if version history is not
appropriately protected by access control, a client can use the
version history of a public resource to identify later versions of
that resource that the user intended to keep private. This
increases the need for reliable authentication and accurate
authorization.
A WebDAV versioning client should be designed to handle a mixture
of 200 (OK) and 404 (Forbidden) responses on attempts to access the
properties and reports that are supported by a resource. For
example, a particular user may be authorized to access the content
and dead properties of a version-controlled resource, but not be
authorized to access the DAV:checked-in, DAV:checked-out, or
DAV:version-history properties of that resource.
16.3 Security Through Obscurity
While it is acknowledged that "obscurity" is not an effective means
of security, it is often a good technique to keep honest people
honest. Within this protocol, version URLs, version history URLs,
and working resource URLs are generated by the server and can be
properly obfuscated so as not to draw attention to them. For
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example, a version of "http://foobar.com/reviews/salaries.html"
might be assigned a URL such as "http://foobar.com/repo/4934943".
16.4 Denial of Service
The auto-versioning mechanism provided by WebDAV can result in a
large number of resources being created on the server, since each
update to a resource could potentially result in the creation of a
new version resource. This increases the risk of a denial of
service attack that exhausts the storage capability of a server.
This risk is especially significant because it can be an
unintentional result of something like an aggressive auto-save
feature provided by an editing client. A server can decrease this
risk by using delta storage techniques to minimize the cost of
additional versions, and by limiting auto-versioning to a locking
client, and thereby decreasing the number of inadvertent version
creations.
17 IANA CONSIDERATIONS
This document uses the namespace defined by RFC 2518 for XML
elements. All other IANA considerations from RFC 2518 are also
applicable to WebDAV Versioning.
18 INTELLECTUAL PROPERTY
The following notice is copied from RFC 2026, Section 10.4, and
describes the position of the IETF concerning intellectual property
claims made against this document.
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use other technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on
the procedures of the IETF with respect to rights in standards-
track and standards-related documentation can be found in BCP-11.
Copies of claims of rights made available for publication and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use
of such proprietary rights by implementers or users of this
specification can be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to practice
this standard. Please address the information to the IETF
Executive Director.
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19 ACKNOWLEDGEMENTS
This protocol is the collaborative product of the authors and the
rest of the DeltaV design team: Boris Bokowski (OTI), Bruce Cragun
(Novell), Jim Doubek (Macromedia), David Durand (INSO), Lisa
Dusseault (Xythos), Chuck Fay (FileNet), Yaron Goland, Mark Hale
(Interwoven), Henry Harbury(Merant), James Hunt, Jeff McAffer
(OTI), Peter Raymond (Merant), Juergen Reuter, Edgar Schwarz
(Marconi), Eric Sedlar (Oracle), Bradley Sergeant, Greg Stein, and
John Vasta (Rational). We would like to acknowledge the foundation
laid for us by the authors of the WebDAV and HTTP protocols upon
which this protocol is layered, and the invaluable feedback from
the WebDAV and DeltaV working groups.
20 REFERENCES
[ISO639] ISO, "Code for the representation of names of languages",
ISO 639:1988, 1998.
[RFC1766] H.T.Alvestrand, "Tags for the Identification of
Languages", Uninett, 1995.
[RFC2026] S.Bradner, "The Internet Standards Process", Harvard,
1996.
[RFC2119] S.Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", Harvard, 1997.
[RFC2277] H.T.Alvestrand, "IETF Policy on Character Sets and
Languages", BCP 18, Uninett, 1998.
[RFC2279] F.Yergeau, "UTF-8, a transformation format of ISO 10646",
Alis Technologies, 1998.
[RFC2396] T.Berners-Lee, R.Fielding, L.Masinter, "Uniform Resource
Identifiers (URI): Generic Syntax", MIT, U.C.Irvine, Xerox, 1998.
[RFC2518] Y.Goland, E.Whitehead, A.Faizi, S.R.Carter, D.Jensen,
"HTTP Extensions for Distributed Authoring - WEBDAV", Microsoft,
U.C.Irvine, Netscape, Novell, 1999.
[RFC2616] R.Fielding, J.Gettys, J.C.Mogul, H.Frystyk, L.Masinter,
P.Leach, and T.Berners-Lee, "Hypertext Transfer Protocol --
HTTP/1.1", U.C.Irvine, Compaq, Xerox, Microsoft, MIT/LCS, 1999.
[RFC3023] M.Murata, S.St.Laurent, D.Kohn, "XML Media Types", IBM,
simonstl.com, Skymoon Ventures, 2001.
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21 AUTHORS' ADDRESSES
Geoffrey Clemm
Rational Software
20 Maguire Road, Lexington, MA 02421
Email: geoffrey.clemm@rational.com
Jim Amsden
IBM
3039 Cornwallis, Research Triangle Park, NC 27709
Email: jamsden@us.ibm.com
Tim Ellison
IBM
Hursley Park, Winchester, UK S021 2JN
Email: tim_ellison@uk.ibm.com
Christopher Kaler
Microsoft
One Microsoft Way, Redmond, WA 90852
Email: ckaler@microsoft.com
Jim Whitehead
UC Santa Cruz, Dept. of Computer Science
1156 High Street, Santa Cruz, CA 95064
Email: ejw@cse.ucsc.edu
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22 APPENDIX A - RESOURCE CLASSIFICATION
This document introduces several different kinds of versioning
resources, such as version-controlled resources, versions, checked-
out resources, and version history resources. As clients discover
resources on a server, they may find it useful to classify those
resources (for example, to make UI decisions on choice of icon and
menu options).
Clients should classify a resource by examining the values of the
DAV:supported-method-set (see Section 3.1.3) and DAV:supported-
live-property-set (see Section 3.1.4) properties of that resource.
The following list shows the supported live properties and methods
for each kind of versioning resource. Where an optional feature
introduces a new kind of versioning resource, that feature is noted
in parentheses following the name of that kind of versioning
resource. If a live property or method is optional for a kind of
versioning resource, the feature that introduces that live property
or method is noted in parentheses following the live property or
method name.
22.1 DeltaV-Compliant Unmapped URL (a URL that identifies no resource)
Supported methods:
- PUT [RFC2616]
- MKCOL [RFC2518]
- MKACTIVITY (activity)
- VERSION-CONTROL (workspace)
- MKWORKSPACE (workspace)
22.2 DeltaV-Compliant Resource
Supported live properties:
- DAV:comment
- DAV:creator-displayname
- DAV:supported-method-set
- DAV:supported-live-property-set
- DAV:supported-report-set
- DAV:workspace (workspace)
- DAV:version-controlled-configuration (baseline)
- all properties defined in WebDAV [RFC2518].
Supported methods:
- REPORT
- all methods defined in WebDAV [RFC2518]
- all methods defined in HTTP/1.1 [RFC2616].
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22.3 DeltaV-Compliant Collection
Supported live properties:
- all DeltaV-compliant resource properties.
Supported methods:
- BASELINE-CONTROL (baseline)
- all DeltaV-compliant resource methods.
22.4 Versionable Resource
Supported live properties:
- all DeltaV-compliant resource properties.
Supported methods:
- VERSION-CONTROL
- all DeltaV-compliant resource methods.
22.5 Version-Controlled Resource
Supported live properties:
- DAV:auto-version
- DAV:version-history (version-history)
- all DeltaV-compliant resource properties.
Supported methods:
- VERSION-CONTROL
- MERGE (merge)
- all DeltaV-compliant resource methods.
22.6 Version
Supported live properties:
- DAV:predecessor-set
- DAV:successor-set
- DAV:checkout-set
- DAV:version-name
- DAV:checkout-fork (in-place-checkout or working resource)
- DAV:checkin-fork (in-place-checkout or working resource)
- DAV:version-history (version-history)
- DAV:label-name-set (label)
- DAV:activity-set (activity)
- all DeltaV-compliant resource properties.
Supported methods:
- LABEL (label)
- CHECKOUT (working-resource)
- all DeltaV-compliant resource methods.
22.7 Checked-In Version-Controlled Resource
Supported live properties:
- DAV:checked-in
- all version-controlled resource properties.
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Supported methods:
- CHECKOUT (checkout-in-place)
- UPDATE (update)
- all version-controlled resource methods.
22.8 Checked-Out Resource
Supported live properties:
- DAV:checked-out
- DAV:predecessor-set
- DAV:checkout-fork (in-place-checkout or working resource)
- DAV:checkin-fork (in-place-checkout or working resource)
- DAV:merge-set (merge)
- DAV:auto-merge-set (merge)
- DAV:unreserved (activity)
- DAV:activity-set (activity)
Supported methods:
- CHECKIN (checkout-in-place or working-resource)
- all DeltaV-compliant resource methods.
22.9 Checked-Out Version-Controlled Resource (checkout-in-place)
Supported live properties:
- all version-controlled resource properties.
- all checked-out resource properties.
Supported methods:
- UNCHECKOUT
- all version-controlled resource methods.
- all checked-out resource methods.
22.10 Working Resource (working-resource)
Supported live properties:
- all DeltaV-compliant resource properties
- all checked-out resource properties
- DAV:auto-update.
Supported methods:
- all checked-out resource methods.
22.11 Version History (version-history)
Supported live properties:
- DAV:version-set
- DAV:root-version
- all DeltaV-compliant resource properties.
Supported methods:
- all DeltaV-compliant resource methods.
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22.12 Workspace (workspace)
Supported live properties:
- DAV:workspace-checkout-set
- DAV:baseline-controlled-collection-set (baseline)
- DAV:current-activity-set (activity)
- all DeltaV-compliant collection properties.
Supported methods:
- all DeltaV-compliant collection methods.
22.13 Activity (activity)
Supported live properties:
- DAV:activity-version-set
- DAV:activity-checkout-set
- DAV:subactivity-set
- DAV:current-workspace-set
- all DeltaV-compliant resource properties.
Supported methods:
- all DeltaV-compliant resource methods.
22.14 Version-Controlled Collection (version-controlled-collection)
Supported live properties:
- DAV:eclipsed-set
- all version-controlled resource properties.
Supported methods:
- all version-controlled resource methods.
22.15 Collection Version (version-controlled-collection)
Supported live properties:
- DAV:version-controlled-binding-set
- all version properties.
Supported methods:
- all version methods.
22.16 Version-Controlled Configuration (baseline)
Supported live properties:
- DAV:baseline-controlled-collection
- all version-controlled resource properties.
Supported methods:
- all version-controlled resource methods.
22.17 Baseline (baseline)
Supported live properties:
- DAV:baseline-collection
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- DAV:subbaseline-set
- all version properties.
Supported methods:
- all version methods.
22.18 Checked-Out Version-Controlled Configuration (baseline)
Supported live properties:
- DAV:subbaseline-set
- all version-controlled configuration properties.
Supported methods:
- all version-controlled configuration methods.
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