WEBDAV Working Group J. Reschke, Ed.
Internet-Draft S. Eissing
Expires: June 2, 2004 greenbytes
December 3, 2003
Including additional properties in WebDAV PROPFIND/allprop requests
draft-reschke-webdav-allprop-include-05
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Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
Recent specifications extending the Web Distributed Authoring
Protocol (WebDAV) restrict the set of properties returned
automatically upon a PROPFIND/allprop request. This specification
defines a method to add specific properties to the set of properties
returned upon PROPFIND/allprop.
Distribution of this document is unlimited. Please send comments to
the Distributed Authoring and Versioning (WebDAV) working group at
w3c-dist-auth@w3.org [1], which may be joined by sending a message
with subject "subscribe" to w3c-dist-auth-request@w3.org [2].
Discussions of the WEBDAV working group are archived at URL: http://
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lists.w3.org/Archives/Public/w3c-dist-auth/.
Table of Contents
1. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Extensions to PROPFIND/allprop . . . . . . . . . . . . . . . . 5
3.1 Example for PROPFIND/allprop/include with extended server . . 5
3.2 Example for PROPFIND/allprop/include with non-extended
server . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Changes to WebDAV DTD . . . . . . . . . . . . . . . . . . . . 9
5. Compatibility Considerations . . . . . . . . . . . . . . . . . 10
6. Internationalization Considerations . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
Normative References . . . . . . . . . . . . . . . . . . . . . 13
Informative References . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 15
A. Alternate syntax proposal from interim WebDAV working
group meeting . . . . . . . . . . . . . . . . . . . . . . . . 16
A.1 PROPFIND/prop extension to include dead properties . . . . . . 16
A.2 Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
B. Change Log (to be removed by RFC Editor before publication) . 18
B.1 Since 'draft-reschke-webdav-allprop-include-00' . . . . . . . 18
B.2 Since 'draft-reschke-webdav-allprop-include-01' . . . . . . . 18
B.3 Since 'draft-reschke-webdav-allprop-include-02' . . . . . . . 18
B.4 Since 'draft-reschke-webdav-allprop-include-03' . . . . . . . 18
B.5 Since 'draft-reschke-webdav-allprop-include-04' . . . . . . . 18
Intellectual Property and Copyright Statements . . . . . . . . 19
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1. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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2. Introduction
Recent specifications extending the "Web Distributed Authoring
Protocol" (WebDAV, [RFC2518]) like "Versioning Extensions to WebDAV"
[RFC3253] and "WebDAV Access Control Protocol" [ACL] restrict the set
of properties returned automatically upon a PROPFIND/allprop request
in order to avoid the expensive computation of properties that the
client in many cases isn't interested in.
However, this change from the behaviour defined in WebDAV can lead to
situations where clients need to perform two requests to retrieve all
properties they are interested in (one using PROPFIND/allprop, then
PROPFIND/prop enumerating the new properties that weren't reported
upon the first request). This specification defines a
backward-compatible extension to add specific properties to the set
of properties returned upon PROPFIND/allprop, thus saving at least
one PROPFIND request.
This document defines an extension element that could ultimately
become part of the core WebDAV protocol. Being just an individual
submission, it currently defines it in the proprietary namespace
http://sapportals.com/xmlns/cm/webdav
instead of the "DAV:" namespace. It uses a prefix of "in:" for
referring to elements in this namespace. However, WebDAV server and
clients are free to use any prefix, provided that there is a
namespace declaration that binds the prefix to the URI of the same
namespace.
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3. Extensions to PROPFIND/allprop
The "allprop" version of PROPFIND is extended to take an optional
in:include element. When present, it contains a set of property names
that shall be reported in addition to those properties that the
server usually would return upon PROPFIND/allprop.
3.1 Example for PROPFIND/allprop/include with extended server
>>Request
PROPFIND /container/front.html HTTP/1.1
Host: www.example.org
Depth: 1
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.example.org/container/front.html
Box type B
1997-12-01T18:27:21-08:00
Example HTML resource
4525
text/html
zzyzx
Monday, 12-Jan-98 09:25:56 GMT
http://www.example.org/vsn/container/front.html-1
HTTP/1.1 200 OK
HTTP/1.1 404 NOT FOUND
In this example, the server has recognized the extension element
in:include and included the properties DAV:checked-in and
DAV:checked-out (as defined in [RFC3253]).
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3.2 Example for PROPFIND/allprop/include with non-extended server
>>Request
PROPFIND /container/front.html HTTP/1.1
Host: www.example.org
Depth: 1
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
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>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://www.example.org/container/front.html
Box type B
1997-12-01T18:27:21-08:00
Example HTML resource
4525
text/html
zzyzx
Monday, 12-Jan-98 09:25:56 GMT
HTTP/1.1 200 OK
In this case the in:include element was simply ignored. The client
can detect this situation by checking for the presence of the
requested properties and will have to issue an additional PROPFIND/
prop request (to retrieve the missing properties).
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4. Changes to WebDAV DTD
Note that the WebDAV DTD is informal only and cannot be used to
validate request or response bodies (due to the inability to properly
work with XML namespaces).
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5. Compatibility Considerations
This specification introduces a new child element for the
DAV:propfind element, defined in Section 4. Old servers will ignore
this element (see [RFC2518], chapter 14). Clients can detect this
situation as outlined in Section 3.2.
Clients not aware of this specification will not be affected at all,
because they will never use the new in:include element in PROPFIND
requests.
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6. Internationalization Considerations
This proposal builds on [RFC2518], and inherits its
internationalizability.
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7. IANA Considerations
This proposal does not introduce any new IANA considerations, since
it does not specify any new namespaces (in the general sense), but
merely uses existing ones.
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Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2518] Goland, Y., Whitehead, E., Faizi, A., Carter, S. and D.
Jensen, "HTTP Extensions for Distributed Authoring --
WEBDAV", RFC 2518, February 1999.
[RFC3253] Clemm, G., Amsden, J., Ellison, T., Kaler, C. and J.
Whitehead, "Versioning Extensions to WebDAV", RFC 3253,
March 2002.
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Informative References
[ACL] Clemm, G., Hopkins, A., Sedlar, E. and J. Whitehead,
"WebDAV Access Control Protocol", ID
draft-ietf-webdav-acl-12, October 2003, .
[ID-RFC2518bis]
Dusseault, L. and J. Crawford, "HTTP Extensions for
Distributed Authoring - WebDAV RFC2518 bis", ID
draft-ietf-webdav-rfc2518bis-05, October 2003, .
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URIs
[1]
[2]
Authors' Addresses
Julian F. Reschke (editor)
greenbytes GmbH
Salzmannstrasse 152
Muenster, NW 48159
Germany
Phone: +49 251 2807760
Fax: +49 251 2807761
EMail: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/
Stefan Eissing
greenbytes GmbH
Salzmannstrasse 152
Muenster, NW 48159
Germany
Phone: +49 251 2807760
Fax: +49 251 2807761
EMail: stefan.eissing@greenbytes.de
URI: http://greenbytes.de/tech/webdav/
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Appendix A. Alternate syntax proposal from interim WebDAV working group
meeting
This section briefly describes an alternate approach to the problem
covered by this draft. It was discussed during the interim WebDAV
working group meeting in January 2003 and was supported by all
meeting attendees. It was also added to the latest draft for the
revision of [RFC2518], [ID-RFC2518bis].
A.1 PROPFIND/prop extension to include dead properties
Additional PROPFIND marshalling:
The DAV:dead-props element can be added to PROPFIND requests that
retrieve named properties using DAV:prop. When present, the server
MUST include all dead properties defined on the resource.
A.2 Example
This example shows the alternate syntax applied to the example from
Section 3.1.
>>Request
PROPFIND /container/front.html HTTP/1.1
Host: www.example.org
Depth: 1
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
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>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
http://www.example.org/container/front.html
Box type B
http://www.example.org/vsn/container/front.html-1
HTTP/1.1 200 OK
HTTP/1.1 404 NOT FOUND
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Appendix B. Change Log (to be removed by RFC Editor before publication)
B.1 Since 'draft-reschke-webdav-allprop-include-00'
Moved element out of "DAV:" namespace.
Updated reference to deltaV (now RFC3253).
Changed examples to explicitly use utf-8 encoding for HTTP content
type and XML encoding.
Updated WebDAV ACL reference to draft 07.
Made sure figures fit in 72 columns.
Split references into "Normative" and "Informative".
B.2 Since 'draft-reschke-webdav-allprop-include-01'
Updated WebDAV ACL reference to draft 09.
B.3 Since 'draft-reschke-webdav-allprop-include-02'
Fixed XML errors in examples (wrong closing href tags).
Replaced domain names in examples according to RFC2606: "www.foo.bar"
by "www.example.org".
Shortened checked-in URI to fit into 72 characters in example.
B.4 Since 'draft-reschke-webdav-allprop-include-03'
Added short description of alternate syntax discussed during interim
WebDAV WG meeting (January 2003).
B.5 Since 'draft-reschke-webdav-allprop-include-04'
DTD fix for dead-props variant. Remove superfluous IP and copyright
sections. Added reference to RFC2518bis. Updated reference to ACL
draft.
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Intellectual Property Statement
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