PROPFIND/allprop/include proposal

Hi,

below is a formalized version of the allprop extension we discussed some
weeks ago (to include ACL/deltaV properties that would not be reported
otherwise). The intent is to have a working paper that

a) can be developed for RFC2518++,

b) can be used for documentation purposes.

Julian



--

Network Working Group                                         J. Reschke
Internet-Draft                                                S. Eissing
Expires: April 5, 2002                                        greenbytes
                                                         October 5, 2001


  Including additional properties in WebDAV PROPFIND/allprop requests
                draft-reschke-webdav-allprop-include-00

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
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Copyright Notice

   Copyright (C) The Internet Society (2001).  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].




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   Discussions of the WEBDAV working group are archived at URL: http://
   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
   8.  Copyright  . . . . . . . . . . . . . . . . . . . . . . . . . . 13
   9.  Intellectual Property  . . . . . . . . . . . . . . . . . . . . 14
       References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 15
       Full Copyright Statement . . . . . . . . . . . . . . . . . . . 16
































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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"
   [deltaV] 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.


































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3. Extensions to PROPFIND/allprop

   The "allprop" version of PROPFIND is extended to take an optional
   <include> element (with namespace-URI "DAV:").  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.foo.bar
      Depth: 1
      Content-Type: text/xml
      Content-Length: xxxx

      <?xml version="1.0"?>
      <propfind xmlns="DAV:">
        <allprop/>
        <include>
          <checked-in/>
          <checked-out/>
        </include>
      </propfind>

    >>Response

      HTTP/1.1 207 Multi-Status
      Content-Type: text/xml
      Content-Length: xxxx

      <?xml version="1.0"?>
      <multistatus xmlns="DAV:">
        <response>
          <href>http://www.foo.bar/container/front.html<href>
          	<propstat>
             <prop>
               <R:bigbox xmlns:R="http://www.foo.bar/boxschema/">
               	<R:BoxType>Box type B</R:BoxType>
               </R:bigbox>
               <creationdate>1997-12-01T18:27:21-08:00</creationdate>
               <displayname>Example HTML resource</displayname>
               <getcontentlength>4525</getcontentlength>
               <getcontenttype>text/html</getcontenttype>
               <getetag>zzyzx</getetag>
               <getlastmodified>Monday, 12-Jan-98 09:25:56
GMT</getlastmodified>



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               <resourcetype/>
               <supportedlock>
                 <lockentry>
                   <lockscope><exclusive/></lockscope>
                   <locktype><write/></locktype>
                 </lockentry>
                 <lockentry>
                   <lockscope><shared/></lockscope>
                   <locktype><write/></locktype>
                  </lockentry>
                </supportedlock>
                <checked-in>

<href>http://www.foo.bar/versions/container/front.html-1</href>
                </checked-in>
             </prop>
             <status>HTTP/1.1 200 OK</status>
           </propstat>
           <propstat>
             <prop>
               <checked-out/>
             </prop>
             <status>HTTP/1.1 404 NOT FOUND</status>
           </propstat>
        </response>
      </multistatus>

   In this example, the server has recognized the extension element
   <include> and included the DAV: properties <checked-in> and <checked-
   out> (as defined in [deltaV]).






















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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.foo.bar
      Depth: 1
      Content-Type: text/xml
      Content-Length: xxxx

      <?xml version="1.0"?>
      <propfind xmlns="DAV:">
        <allprop/>
        <include>
          <checked-in/>
          <checked-out/>
        </include>
      </propfind>

    >>Response

      HTTP/1.1 207 Multi-Status
      Content-Type: text/xml
      Content-Length: xxxx

      <?xml version="1.0"?>
      <multistatus xmlns="DAV:">
        <response>
          <href>http://www.foo.bar/container/front.html<href>
          	<propstat>
             <prop>
               <R:bigbox xmlns:R="http://www.foo.bar/boxschema/">
               	<R:BoxType>Box type B</R:BoxType>
               </R:bigbox>
               <creationdate>1997-12-01T18:27:21-08:00</creationdate>
               <displayname>Example HTML resource</displayname>
               <getcontentlength>4525</getcontentlength>
               <getcontenttype>text/html</getcontenttype>
               <getetag>zzyzx</getetag>
               <getlastmodified>Monday, 12-Jan-98 09:25:56
GMT</getlastmodified>
               <resourcetype/>
               <supportedlock>
                 <lockentry>
                   <lockscope><exclusive/></lockscope>
                   <locktype><write/></locktype>
                 </lockentry>
                 <lockentry>
                   <lockscope><shared/></lockscope>



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                   <locktype><write/></locktype>
                  </lockentry>
                </supportedlock>
             </prop>
             <status>HTTP/1.1 200 OK</status>
           </propstat>
        </response>
      </multistatus>

   In this case the <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

   <!ELEMENT propfind ((allprop, include+) | propname | prop) >
   <!ELEMENT include ANY >

   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 <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 <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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8. Copyright

   To be supplied by the RFC Editor.
















































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9. Intellectual Property

   To be supplied by the RFC Editor.
















































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References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2518]  Goland, Y., Whitehead, E., Faizi, A., Carter, S. and D.
              Jensen, "HTTP Extensions for Distributed Authoring --
              WEBDAV", RFC 2518, February 1999.

   [deltaV]   Clemm, G., Amsden, J., Ellison, T., Kaler, C. and J.
              Whitehead, "Versioning Extensions to WebDAV", ID draft-
              ietf-deltav-versioning-18, September 2001, <http://
              www.webdav.org/deltav/protocol/draft-ietf-deltav-
              versioning-18.htm>.

   [ACL]      Clemm, G., Hopkins, A., Sedlar, E. and J. Whitehead,
              "WebDAV Access Control Protocol", ID draft-ietf-webdav-
              acl-06, June 2001, <http://www.webdav.org/acl/protocol/
              draft-ietf-webdav-acl-06.htm>.

   [1]  <mailto:w3c-dist-auth@w3.org>

   [2]  <mailto:w3c-dist-auth-request@w3.org?subject=subscribe>


Authors' Addresses

   Julian F. Reschke
   greenbytes GmbH
   Salzmannstrasse 152
   Muenster, NW  48159
   Germany

   EMail: julian.reschke@greenbytes.de


   Stefan Eissing
   greenbytes GmbH
   Salzmannstrasse 152
   Muenster, NW  48159
   Germany

   EMail: stefan.eissing@greenbytes.de








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Full Copyright Statement

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

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Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















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Received on Friday, 5 October 2001 05:38:38 UTC