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Versions: 00 01 02 03 04 05 06 07 08 09 10 11 12 13 RFC 4437

WEBDAV Working Group                                            J. Slein
Internet-Draft                                                     Xerox
Expires: March 10, 2004                                     J. Whitehead
                                                         U.C. Santa Cruz
                                                                J. Davis
                                                               CourseNet
                                                                G. Clemm
                                                                Rational
                                                                  C. Fay
                                                                 FileNet
                                                             J. Crawford
                                                                     IBM
                                                         J. Reschke, Ed.
                                                              greenbytes
                                                      September 10, 2003


                  WebDAV Redirect Reference Resources
               draft-ietf-webdav-redirectref-protocol-04

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
   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.

   This Internet-Draft will expire on March 10, 2004.

Copyright Notice

   Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

   This specification defines redirect reference resources.  A redirect



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   reference resource is a resource whose default response is an HTTP/
   1.1 302 (Found) status code, redirecting the client to a different
   resource, the target resource.  A redirect reference makes it
   possible to access the target resource indirectly, through any URI
   mapped to the redirect reference resource.  There are no integrity
   guarantees associated with redirect reference resources.

   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://
   lists.w3.org/Archives/Public/w3c-dist-auth/.

Table of Contents

   1.   Introduction . . . . . . . . . . . . . . . . . . . . . . . .   5
   2.   Notational Conventions . . . . . . . . . . . . . . . . . . .   7
   3.   Terminology  . . . . . . . . . . . . . . . . . . . . . . . .   8
   4.   Overview of Redirect Reference Resources . . . . . . . . . .   9
   5.   Creating a Redirect Reference Resource . . . . . . . . . . .  10
   5.1  MKRESOURCE . . . . . . . . . . . . . . . . . . . . . . . . .  10
   5.2  Example: Creating a Redirect Reference Resource with
        MKRESOURCE . . . . . . . . . . . . . . . . . . . . . . . . .  11
   6.   Operations on Redirect Reference Resources . . . . . . . . .  13
   6.1  Example: GET on a Redirect Reference Resource  . . . . . . .  14
   6.2  Example: PUT on a Redirect Reference Resource with
        Apply-To-Redirect-Ref  . . . . . . . . . . . . . . . . . . .  14
   6.3  Example: PROPPATCH on a Redirect Reference Resource  . . . .  15
   7.   Operations on Collections That Contain Redirect Reference
        Resources  . . . . . . . . . . . . . . . . . . . . . . . . .  16
   7.1  MOVE and DELETE on Collections That Contain Redirect
        References . . . . . . . . . . . . . . . . . . . . . . . . .  16
   7.2  LOCK on a Collection That Contains Redirect References . . .  17
   7.3  Example: PROPFIND on a Collection with Redirect Reference
        Resources  . . . . . . . . . . . . . . . . . . . . . . . . .  17
   7.4  Example: PROPFIND with Apply-To-Redirect-Ref on a
        Collection with Redirect Reference Resources . . . . . . . .  18
   7.5  Example: COPY on a Collection That Contains a Redirect
        Reference Resource . . . . . . . . . . . . . . . . . . . . .  20
   7.6  Example: LOCK on a Collection That Contains a Redirect
        Reference Resource . . . . . . . . . . . . . . . . . . . . .  21
   8.   Operations on Targets of Redirect Reference Resources  . . .  24
   9.   Relative URIs in DAV:reftarget . . . . . . . . . . . . . . .  25
   9.1  Example: Resolving a Relative URI in a MKRESOURCE Request  .  25
   9.2  Example: Resolving a Relative URI in a Multi-Status
        Response . . . . . . . . . . . . . . . . . . . . . . . . . .  26



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   10.  Redirect References to Collections . . . . . . . . . . . . .  28
   11.  Headers  . . . . . . . . . . . . . . . . . . . . . . . . . .  30
   11.1 Redirect-Ref Response Header . . . . . . . . . . . . . . . .  30
   11.2 Apply-To-Redirect-Ref Request Header . . . . . . . . . . . .  30
   12.  Properties . . . . . . . . . . . . . . . . . . . . . . . . .  31
   12.1 reftarget Property . . . . . . . . . . . . . . . . . . . . .  31
   12.2 location Pseudo-Property . . . . . . . . . . . . . . . . . .  31
   13.  XML Elements . . . . . . . . . . . . . . . . . . . . . . . .  32
   13.1 redirectref XML Element  . . . . . . . . . . . . . . . . . .  32
   14.  Extensions to the DAV:response XML Element for
        Multi-Status Responses . . . . . . . . . . . . . . . . . . .  33
   15.  Capability Discovery . . . . . . . . . . . . . . . . . . . .  34
   15.1 Example: Discovery of Support for Redirect Reference
        Resources  . . . . . . . . . . . . . . . . . . . . . . . . .  34
   16.  Security Considerations  . . . . . . . . . . . . . . . . . .  35
   16.1 Privacy Concerns . . . . . . . . . . . . . . . . . . . . . .  35
   16.2 Redirect Loops . . . . . . . . . . . . . . . . . . . . . . .  35
   16.3 Redirect Reference Resources and Denial of Service . . . . .  35
   16.4 Revealing Private Locations  . . . . . . . . . . . . . . . .  35
   17.  Internationalization Considerations  . . . . . . . . . . . .  37
   18.  IANA Considerations  . . . . . . . . . . . . . . . . . . . .  38
   19.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . .  39
        Normative References . . . . . . . . . . . . . . . . . . . .  40
        Authors' Addresses . . . . . . . . . . . . . . . . . . . . .  40
   A.   Changes to the WebDAV Document Type Definition . . . . . . .  42
   B.   Change Log (to be removed by RFC Editor before
        publication) . . . . . . . . . . . . . . . . . . . . . . . .  43
   B.1  Since draft-ietf-webdav-redirectref-protocol-02  . . . . . .  43
   B.2  Since draft-ietf-webdav-redirectref-protocol-03  . . . . . .  43
   C.   Resolved issues (to be removed by RFC Editor before
        publication) . . . . . . . . . . . . . . . . . . . . . . . .  44
   C.1  lc-07-bind . . . . . . . . . . . . . . . . . . . . . . . . .  44
   C.2  lc-08-bind . . . . . . . . . . . . . . . . . . . . . . . . .  44
   C.3  lc-34-bind . . . . . . . . . . . . . . . . . . . . . . . . .  44
   C.4  lc-83-bind . . . . . . . . . . . . . . . . . . . . . . . . .  44
   C.5  lc-12-bind . . . . . . . . . . . . . . . . . . . . . . . . .  45
   C.6  lc-35-bind . . . . . . . . . . . . . . . . . . . . . . . . .  45
   C.7  lc-01-body . . . . . . . . . . . . . . . . . . . . . . . . .  45
   C.8  lc-14-bind . . . . . . . . . . . . . . . . . . . . . . . . .  45
   C.9  lc-15-direct-ref . . . . . . . . . . . . . . . . . . . . . .  46
   C.10 lc-39-no-reference-or-direct-resource  . . . . . . . . . . .  46
   C.11 lc-40-direct . . . . . . . . . . . . . . . . . . . . . . . .  46
   C.12 lc-45-apply-to-rr  . . . . . . . . . . . . . . . . . . . . .  47
   C.13 lc-01A-body  . . . . . . . . . . . . . . . . . . . . . . . .  47
   C.14 lc-31-MKCOL  . . . . . . . . . . . . . . . . . . . . . . . .  47
   C.15 lc-67-redirectref  . . . . . . . . . . . . . . . . . . . . .  47
   C.16 lc-54-s10  . . . . . . . . . . . . . . . . . . . . . . . . .  48
   C.17 lc-78-directory  . . . . . . . . . . . . . . . . . . . . . .  48



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   C.18 lc-82-iana . . . . . . . . . . . . . . . . . . . . . . . . .  48
   D.   Open issues (to be removed by RFC Editor before
        publication) . . . . . . . . . . . . . . . . . . . . . . . .  49
   D.1  lc-85-301  . . . . . . . . . . . . . . . . . . . . . . . . .  49
   D.2  lc-38-not-hierarchical . . . . . . . . . . . . . . . . . . .  49
   D.3  lc-36-server . . . . . . . . . . . . . . . . . . . . . . . .  49
   D.4  lc-33-forwarding . . . . . . . . . . . . . . . . . . . . . .  49
   D.5  lc-56-notjusthttp  . . . . . . . . . . . . . . . . . . . . .  50
   D.6  lc-37-integrity  . . . . . . . . . . . . . . . . . . . . . .  50
   D.7  3-terminology-redirectref  . . . . . . . . . . . . . . . . .  50
   D.8  lc-43-webdav . . . . . . . . . . . . . . . . . . . . . . . .  50
   D.9  lc-19-direct-ref . . . . . . . . . . . . . . . . . . . . . .  51
   D.10 lc-04-standard-data-container  . . . . . . . . . . . . . . .  51
   D.11 lc-05-standard-data-container  . . . . . . . . . . . . . . .  51
   D.12 lc-20-intro-mkresource . . . . . . . . . . . . . . . . . . .  51
   D.13 lc-22-coll . . . . . . . . . . . . . . . . . . . . . . . . .  52
   D.14 lc-25-atomic . . . . . . . . . . . . . . . . . . . . . . . .  52
   D.15 lc-41-no-webdav  . . . . . . . . . . . . . . . . . . . . . .  52
   D.16 lc-42-no-webdav  . . . . . . . . . . . . . . . . . . . . . .  52
   D.17 lc-58-update . . . . . . . . . . . . . . . . . . . . . . . .  53
   D.18 lc-23-body . . . . . . . . . . . . . . . . . . . . . . . . .  53
   D.19 lc-24-properties . . . . . . . . . . . . . . . . . . . . . .  53
   D.20 lc-47-207  . . . . . . . . . . . . . . . . . . . . . . . . .  54
   D.21 lc-48-s6 . . . . . . . . . . . . . . . . . . . . . . . . . .  54
   D.22 lc-28-lang . . . . . . . . . . . . . . . . . . . . . . . . .  55
   D.23 lc-29-lang . . . . . . . . . . . . . . . . . . . . . . . . .  55
   D.24 lc-49-put  . . . . . . . . . . . . . . . . . . . . . . . . .  55
   D.25 lc-44-pseudo . . . . . . . . . . . . . . . . . . . . . . . .  55
   D.26 lc-61-pseudo . . . . . . . . . . . . . . . . . . . . . . . .  56
   D.27 lc-60-ex . . . . . . . . . . . . . . . . . . . . . . . . . .  56
   D.28 lc-62-oldclient  . . . . . . . . . . . . . . . . . . . . . .  56
   D.29 lc-63-move . . . . . . . . . . . . . . . . . . . . . . . . .  56
   D.30 lc-06-reftarget-relative . . . . . . . . . . . . . . . . . .  57
   D.31 lc-57-noautoupdate . . . . . . . . . . . . . . . . . . . . .  57
   D.32 lc-71-relative . . . . . . . . . . . . . . . . . . . . . . .  57
   D.33 lc-53-s10  . . . . . . . . . . . . . . . . . . . . . . . . .  58
   D.34 lc-72-trailingslash  . . . . . . . . . . . . . . . . . . . .  58
   D.35 lc-50-blindredirect  . . . . . . . . . . . . . . . . . . . .  58
   D.36 lc-74-terminology  . . . . . . . . . . . . . . . . . . . . .  59
   D.37 lc-75-ignore . . . . . . . . . . . . . . . . . . . . . . . .  59
   D.38 lc-76-location . . . . . . . . . . . . . . . . . . . . . . .  59
   D.39 lc-79-accesscontrol  . . . . . . . . . . . . . . . . . . . .  59
   D.40 lc-80-i18n . . . . . . . . . . . . . . . . . . . . . . . . .  60
   D.41 lc-55-iana . . . . . . . . . . . . . . . . . . . . . . . . .  60
        Intellectual Property and Copyright Statements . . . . . . .  61






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1. Introduction

   This is one of a pair of specifications that extend the WebDAV
   Distributed Authoring Protocol to enable clients to create new access
   paths to existing resources.  This capability is useful for several
   reasons:

   URIs of WebDAV-compliant resources are hierarchical and correspond to
   a hierarchy of collections in resource space.  The WebDAV Distributed
   Authoring Protocol makes it possible to organize these resources into
   hierarchies, placing them into groupings, known as collections, which
   are more easily browsed and manipulated than a single flat
   collection. However, hierarchies require categorization decisions
   that locate resources at a single location in the hierarchy, a
   drawback when a resource has multiple valid categories. For example,
   in a hierarchy of vehicle descriptions containing collections for
   cars and boats, a description of a combination car/boat vehicle could
   belong in either collection. Ideally, the description should be
   accessible from both. Allowing clients to create new URIs that access
   the existing resource lets them put that resource into multiple
   collections.

   Hierarchies also make resource sharing more difficult, since
   resources that have utility across many collections are still forced
   into a single collection. For example, the mathematics department at
   one university might create a collection of information on fractals
   that contains bindings to some local resources, but also provides
   access to some resources at other universities.  For many reasons, it
   may be undesirable to make physical copies of the shared resources on
   the local server: to conserve disk space, to respect copyright
   constraints, or to make any changes in the shared resources visible
   automatically. Being able to create new access paths to existing
   resources in other collections or even on other servers is useful for
   this sort of case.

   The redirect reference resources defined here provide a mechanism for
   creating alternative access paths to existing resources.  A redirect
   reference resource is a resource in one collection whose purpose is
   to forward requests to another resource (its target), possibly in a
   different collection.  In this way, it allows clients to submit
   requests to the target resource from another collection.  It
   redirects most requests to the target resource using the HTTP 302
   (Found) status code, thereby providing a form of mediated access to
   the target resource.

   A redirect reference is a resource, and so can have properties and a
   body of its own.  Properties of a redirect reference resource can
   contain such information as who created the reference, when, and why.



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   Since redirect reference resources are implemented using HTTP 302
   responses, it generally takes two round trips to submit a request to
   the intended resource.  Servers are not required to enforce the
   integrity of redirect references.  Redirect references work equally
   well for local resources and for resources that reside on a different
   server from the reference.

   The remainder of this document is structured as follows: Section 3
   defines terms that will be used throughout the specification.
   Section 4 provides an overview of redirect reference resources.
   Section 5 discusses how to create a redirect reference resource.
   Section 6 defines the semantics of existing methods when applied to
   redirect reference resources, and Section 7 discusses their semantics
   when applied to collections that contain redirect reference
   resources. Sections 8 through 10 discuss several other issues raised
   by the existence of redirect reference resources.  Sections 11
   through 14 define the new headers, properties, and XML elements
   required to support redirect reference resources.  Section 15
   discusses capability discovery.  Sections 16 through 18 present the
   security, internationalization, and IANA concerns raised by this
   specification. The remaining sections provide a variety of supporting
   information.





























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2. Notational Conventions

   Since this document describes a set of extensions to the WebDAV
   Distributed Authoring Protocol [RFC2518], itself an extension to the
   HTTP/1.1 protocol, the augmented BNF used here to describe protocol
   elements is exactly the same as described in Section 2.1 of
   [RFC2616]. Since this augmented BNF uses the basic production rules
   provided in Section 2.2 of [RFC2616], these rules apply to this
   document as well.

   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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3. Terminology

   The terminology used here follows and extends that in the WebDAV
   Distributed Authoring Protocol specification [RFC2518]. Definitions
   of the terms resource, Uniform Resource Identifier (URI), and Uniform
   Resource Locator (URL) are provided in [RFC2396].

   Redirect Reference Resource

      A resource created to redirect all requests made to it, using 302
      (Found), to a defined target resource.

   Non-Reference Resource

      A resource that is not a reference to another resource.

   Target Resource

      The resource to which requests are forwarded by a reference
      resource.































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4. Overview of Redirect Reference Resources

   For all operations submitted to a redirect reference resource, the
   default response is a 302 (Found), accompanied by the Redirect-Ref
   header (defined in Section 11.1 below) and the Location header set to
   the URI of the target resource.  With this information, the client
   can resubmit the request to the URI of the target resource.

   A redirect reference resource never automatically forwards requests
   to its target resource. Redirect resources bring the same benefits as
   links in HTML documents. They can be created and maintained without
   the involvement or even knowledge of their target resource. This
   reduces the cost of linking between resources."

   If the client is aware that it is operating on a redirect reference
   resource, it can resolve the reference by retrieving the reference
   resource's DAV:reftarget property (defined in Section 12.1 below),
   whose value contains the URI of the target resource.  It can then
   submit requests to the target resource.

   A redirect reference resource is a new type of resource. To
   distinguish redirect reference resources from non-reference
   resources, a new value of the DAV:resourcetype property (defined in
   [RFC2518]), DAV:redirectref, is defined in Section 13.1 below.

   Since a redirect reference resource is a resource, it can have its
   own properties and body, and methods can be applied to the reference
   resource as well as to its target resource.  The
   Apply-To-Redirect-Ref request header (defined in Section 11.2 below)
   is provided so that referencing-aware clients can control whether an
   operation is applied to the redirect reference resource or to its
   target resource.  The Apply-To-Redirect-Ref header can be used with
   most requests to redirect reference resources.  This header is
   particularly useful with PROPFIND, to retrieve the reference
   resource's own properties.
















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5. Creating a Redirect Reference Resource

   The MKRESOURCE method is used to create new redirect reference
   resources.  As defined in Section 5.1, MKRESOURCE can be used to
   create a resource of any type other than standard data containers and
   collections.  In order to create a redirect reference resource using
   MKRESOURCE, the values of two properties must be set in the body of
   the MKRESOURCE request.  The value of DAV:resourcetype MUST be set to
   DAV:redirectref, a new value of DAV:resourcetype defined in Section
   13.1. The value of DAV:reftarget MUST be set to the URI of the target
   resource.

   Used in this way, the MKRESOURCE method creates a redirect reference
   resource whose target is identified by the DAV:reftarget property.

5.1 MKRESOURCE

   The MKRESOURCE method requests the creation of a resource and
   initialization of its properties.  It allows resources other than
   standard data containers and collections to be created and their
   properties initialized in one atomic operation.

   Preconditions:

      A resource MUST NOT exist at the Request-URI.

   Request Marshalling:

      The location of the new resource to be created is specified by the
      Request-URI.

      The request body of the MKRESOURCE method MUST consist of the
      DAV:propertyupdate XML element defined in Section 12.13 of
      [RFC2518].

   Postconditions:

      If the response status code is 201, a new resource exists at the
      Request-URI.

      The body of the new resource is empty.

      The properties of the new resource are as specified by the
      DAV:propertyupdate request body, using PROPPATCH semantics. If the
      DAV:propertyupdate does not specify a DAV:resourcetype, the
      resource will be a standard data container.

      If the response status code is not 201, then a new resource is not



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      created at the Request-URI, and any existing resource at the
      Request-URI is unaffected.

   Response Marshalling:

      Responses from a MKRESOURCE request MUST NOT be cached, as
      MKRESOURCE has non-idempotent semantics.

      The following status codes can be expected in responses to
      MKRESOURCE:

      201 (Created): The new resource was successfully created.

      207 (Multi-Status): This response is generated if an error was
      encountered while initializing the properties of the resource, in
      which case the response is as defined in Section 8.2.1 of
      [RFC2518].

      403 (Forbidden): The server does not allow the creation of the
      requested resource type at the requested location, or the parent
      collection of the Request-URI exists but cannot accept members.

      409 (Conflict): A resource cannot be created at the Request-URI
      because the parent collection for the resource does not exist, or
      because there is already a resource at that request-URL.

      423 (Locked): The Request-URI is locked, and the lock token was
      not passed with the request.

      507 (Insufficient Storage): The server does not have sufficient
      space to record the state of the resource.


5.2 Example: Creating a Redirect Reference Resource with MKRESOURCE

   >> Request:

   MKRESOURCE /~whitehead/dav/spec08.ref HTTP/1.1
   Host: www.ics.uci.edu
   Content-Type: text/xml; charset="utf-8"
   Content-Length: xxx

   <?xml version="1.0" encoding="utf-8" ?>
   <D:propertyupdate xmlns:D="DAV:">
     <D:set>
       <D:prop>
         <D:resourcetype><D:redirectref/></D:resourcetype>
       <D:reftarget>



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         <D:href>/i-d/draft-webdav-protocol-08.txt</D:href>
       </D:reftarget>
     </D:prop>
     </D:set>
   </D:propertyupdate>

    >> Response:

   HTTP/1.1 201 Created

   This request resulted in the creation of a new redirect reference
   resource at www.ics.uci.edu/~whitehead/dav/spec08.ref, which points
   to the resource identified by the DAV:reftarget property. In this
   example, the target resource is identified by the URI http://
   www.ics.uci.edu/i-d/draft-webdav-protocol-08.txt. The redirect
   reference resource's DAV:resourcetype property is set to
   DAV:redirectref.


































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6. Operations on Redirect Reference Resources

   Although non-referencing-aware clients cannot create reference
   resources, they should be able to submit requests through the
   reference resources created by reference-aware WebDAV clients.  They
   should be able to follow any references to their targets.  To make
   this possible, a server that receives any request made via a redirect
   reference resource MUST return a 302 (Found) status code, unless the
   request includes an Apply-To-Redirect-Ref header. The client and
   server MUST follow [RFC2616] Section 10.3.3 "302 Found," but with
   these additional rules:

   o  The Location response header MUST contain an absolute URI that
      identifies the target of the reference resource.

   o  The response MUST include the Redirect-Ref header.  This header
      allows reference-aware WebDAV clients to recognize the resource as
      a reference resource and understand the reason for the
      redirection.

   A reference-aware WebDAV client can act on this response in one of
   two ways.  It can, like a non-referencing client, resubmit the
   request to the URI in the Location header in order to operate on the
   target resource.  Alternatively, it can resubmit the request to the
   URI of the redirect reference resource with the Apply-To-Redirect-Ref
   header in order to operate on the reference resource itself.  If the
   Apply-To-Redirect-Ref header is present, the request MUST be applied
   to the reference resource itself, and a 302 response MUST NOT be
   returned.

   A reference-aware client may know before submitting its request that
   the Request-URI identifies a redirect reference resource. In this
   case, if the client wants to apply the method to the reference
   resource, it can save the round trip caused by the 302 response by
   using an Apply-To-Redirect-Ref header in its initial request to the
   URI.

   A few methods need additional explanation:

   The Apply-To-Redirect-Ref header can be used with GET or HEAD to
   retrieve the entity headers of a redirect reference resource.  When
   Apply-To-Redirect-Ref is used with GET or HEAD, the Redirect-Ref
   entity header MUST be returned.

   A redirect reference resource MAY have a body, though none is defined
   for it in this specification.  The PUT method can be used, with
   Apply-To-Redirect-Ref, to create or replace the body of a redirect
   reference resource.



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6.1 Example: GET on a Redirect Reference Resource

    >> Request:

   GET /bar.html HTTP/1.1
   Host: www.foo.com

    >> Response:

   HTTP/1.1 302 Found
   Location: http://www.svr.com/Internet/xxspec08.html
   Redirect-Ref:

   Since /bar.html is a redirect reference resource and the
   Apply-To-Redirect-Ref header is not included in the request, the
   response is a 302 (Found).  The Redirect-Ref header informs a
   reference-aware client that this is not an ordinary HTTP 1.1
   redirect, but is a redirect reference resource.  The URI of the
   target resource is provided in the Location header so that the client
   can resubmit the request to the target resource.

6.2 Example: PUT on a Redirect Reference Resource with
    Apply-To-Redirect-Ref

    >> Request:

   PUT /bar.html HTTP/1.1
   Host: www.foo.com
   Apply-To-Redirect-Ref:
   Content-Type: text/xml; charset="utf-8"
   Content-Length: xxxx

   . . . some content . . .

    >> Response:

   HTTP/1.1 200 OK

   Although /bar.html is a redirect reference resource, the presence of
   the Apply-To-Redirect-Ref header prevents a 302 response, and instead
   causes the request to be applied to the reference resource.  The
   result in this case is that the reference resource is replaced by a
   non-reference resource having the content submitted with the request.








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6.3 Example: PROPPATCH on a Redirect Reference Resource

    >> Request:

   PROPPATCH /bar.html HTTP/1.1
   Host: www.foo.com
   Content-Type: text/xml; charset="utf-8"
   Content-Length: xxxx

   <?xml version="1.0" encoding="utf-8" ?>
   <D:propertyupdate xmlns:D="DAV:"
   xmlns:Z="http://www.w3.com/standards/z39.50/">
     <D:set>
       <D:prop>
         <Z:authors>
           <Z:Author>Jim Whitehead</Z:Author>
           <Z:Author>Roy Fielding</Z:Author>
         </Z:authors>
       </D:prop>
     </D:set>
     <D:remove>
       <D:prop>
         <Z:Copyright-Owner/>
       </D:prop>
     </D:remove>
   </D:propertyupdate>

    >> Response:

   HTTP/1.1 302 Found
   Location: http://www.svr.com/Internet/xxspec08.html
   Redirect-Ref:

   Since /bar.html is a redirect reference resource and the
   Apply-To-Redirect-Ref header is not included in the request, the
   response is a 302 (Found).  The Redirect-Ref header informs a
   reference-aware client that this is not an ordinary HTTP 1.1
   redirect, but is a redirect reference resource.  The URI of the
   target resource is provided in the Location header so that the client
   can resubmit the request to the target resource.











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7. Operations on Collections That Contain Redirect Reference Resources

   Consistent with the rules in Section 6, the response for each
   redirect reference encountered while processing a collection MUST be
   a 302 (Found) unless a Apply-To-Redirect-Ref header is included with
   the request.  The overall response will therefore be a 207
   (Multi-Status). Since a Location header and Redirect-Ref header
   cannot be returned for each redirect reference encountered, the same
   information is provided using properties in the response elements for
   those resources.  The DAV:location pseudo-property and the
   DAV:resourcetype property MUST be included with the 302 status code.
   This necessitates an extension to the syntax of the DAV:response
   element that was defined in [RFC2518]. The extension is defined in
   Section 14 below.

   A referencing-aware client can tell from the DAV:resourcetype
   property that the collection contains a redirect reference resource.
   The DAV:location pseudo-property contains the absolute URI of the
   target resource.  A referencing-aware client can either use the URI
   value of the DAV:location pseudo-property to resubmit its request to
   the target resource, or it can submit the request to the redirect
   reference resource with Apply-To-Redirect-Ref.

   It is recommended that future editors of [RFC2518] define the
   DAV:location pseudo-property in [RFC2518], so that non-referencing
   clients will also be able to use the response to operate on the
   target resource.  (This will also enable clients to operate on
   traditional HTTP/1.1 302 responses in Multi-Status responses.) Until
   then, non-referencing clients will not be able to process 302
   responses from redirect reference resources encountered while
   processing a collection.

   The Apply-To-Redirect-Ref header (defined in Section 11.2) MAY be
   used with any request on a collection.  If present, it will be
   applied to all redirect reference resources encountered while
   processing the collection.

7.1 MOVE and DELETE on Collections That Contain Redirect References

   DELETE removes the binding that corresponds to the Request-URI.  MOVE
   removes that binding and creates a new binding to the same resource.
   In cases where DELETE and MOVE are applied to a collection, these
   operations affect all the descendents of the collection, but they do
   so indirectly.  There is no need to visit each descendent in order to
   process the request.  Consequently, even if there are redirect
   reference resources in a tree that is being deleted or moved, there
   will be no 302 responses from the redirect reference resources.




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7.2 LOCK on a Collection That Contains Redirect References

   LOCK poses special problems because it is atomic. An attempt to lock
   (with Depth: infinity) a collection that contains redirect references
   will always fail.  The Multi-Status response will contain a 302
   response for each redirect reference.

   Reference-aware clients can lock the collection by using
   Apply-To-Redirect-Ref, and, if desired, lock the targets of the
   redirect references individually.

   Non-referencing clients must resort to locking each resource
   individually.

7.3 Example: PROPFIND on a Collection with Redirect Reference Resources

   Suppose a PROPFIND request with Depth: infinity is submitted to the
   following collection, with the members shown here:

   http://www.svr.com/MyCollection/
        (non-reference resource) diary.html
        (redirect reference resource) nunavut

    >> Request:

   PROPFIND /MyCollection/ HTTP/1.1
   Host: www.svr.com
   Depth: infinity
   Content-Type: text/xml
   Content-Length: xxxx

   <?xml version="1.0" ?>
   <D:propfind xmlns:D="DAV: ">
     <D:prop xmlns:J="http://www.svr.com/jsprops/">
       <D:resourcetype/>
       <J:keywords/>
     </D:prop>
   </D:propfind>

    >> Response:

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

   <?xml version="1.0" ?>
   <D:multistatus xmlns:D="DAV:" xmlns:J="http://www.svr.com/jsprops/">
     <D:response>



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       <D:href>http://www.svr.com/MyCollection/</D:href>
       <D:propstat>
         <D:prop>
           <D:resourcetype><D:collection/></D:resourcetype>
           <J:keywords>diary, interests, hobbies</J:keywords>
         </D:prop>
         <D:status>HTTP/1.1 200 OK</D:status>
       </D:propstat>
     </D:response>
     <D:response>
       <D:href>http://www.svr.com/MyCollection/diary.html</D:href>
       <D:propstat>
         <D:prop>
           <D:resourcetype/>
           <J:keywords>diary, travel, family, history</J:keywords>
         </D:prop>
         <D:status>HTTP/1.1 200 OK</D:status>
       </D:propstat>
     </D:response>
     <D:response>
       <D:href>http://www.svr.com/MyCollection/nunavut</D:href>
       <D:status>HTTP/1.1 302 Found</D:status>
       <D:prop>
         <D:location>
           <D:href>http://www.inac.gc.ca/art/inuit/</D:href>
         </D:location>
         <D:resourcetype><D:redirectref/></D:resourcetype>
       </D:prop>
     </D:response>
   </D:multistatus>

   In this example the Depth header is set to infinity, and the
   Apply-To-Redirect-Ref header is not used.  The collection contains
   one URI that identifies a redirect reference resource.  The response
   element for the redirect reference resource has a status of 302
   (Found), and includes a DAV:prop element with the DAV:location
   pseudo-property and the DAV:resourcetype property to allow clients to
   retrieve the properties of its target resource.  (The response
   element for the redirect reference resource does not include the
   requested properties.  The client can submit another PROPFIND request
   to the URI in the DAV:location pseudo-property to retrieve those
   properties.)

7.4 Example: PROPFIND with Apply-To-Redirect-Ref on a Collection with
    Redirect Reference Resources

   Suppose a PROPFIND request with Apply-To-Redirect-Ref and Depth:
   infinity is submitted to the following collection, with the members



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   shown here:

   /MyCollection/
        (non-reference resource) diary.html
        (redirect reference resource) nunavut

    >> Request:

   PROPFIND /MyCollection/ HTTP/1.1
   Host: www.svr.com
   Depth: infinity
   Apply-To-Redirect-Ref:
   Content-Type: text/xml
   Content-Length: xxxx

   <?xml version="1.0" ?>
   <D:propfind xmlns:D="DAV:">
     <D:prop>
       <D:resourcetype/>
       <D:reftarget/>
     </D:prop>
   </D:propfind>

    >> Response:

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

   <?xml version="1.0" ?>
   <D:multistatus xmlns:D="DAV:">
     <D:response>
       <D:href>http://www.svr.com/MyCollection/</D:href>
       <D:propstat>
         <D:prop>
           <D:resourcetype><D:collection/></D:resourcetype>
         </D:prop>
         <D:status>HTTP/1.1 200 OK</D:status>
       </D:propstat>
       <D:propstat>
         <D:prop><D:reftarget/></D:prop>
         <D:status>HTTP/1.1 404 Not Found</D:status>
       </D:propstat>
     </D:response>
     <D:response>
       <D:href>http://www.svr.com/MyCollection/diary.html</D:href>
       <D:propstat>
         <D:prop>



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           <D:resourcetype/>
         </D:prop>
         <D:status>HTTP/1.1 200 OK</D:status>
       </D:propstat>
       <D:propstat>
         <D:prop><D:reftarget/></D:prop>
         <D:status>HTTP/1.1 404 Not Found</D:status>
       </D:propstat>
     </D:response>
     <D:response>
       <D:href>http://www.svr.com/MyCollection/nunavut</D:href>
       <D:propstat>
         <D:prop>
           <D:resourcetype><D:redirectref/></D:resourcetype>
           <D:reftarget>
             <D:href>http://www.inac.gc.ca/art/inuit/</D:href>
           </D:reftarget>
         </D:prop>
       <D:status>HTTP/1.1 200 OK</D:status>
       </D:propstat>
     </D:response>
   </D:multistatus>

   Since the Apply-To-Redirect-Ref header is present, the response shows
   the properties of the redirect reference resource in the collection
   rather than reporting a 302 status.

7.5 Example: COPY on a Collection That Contains a Redirect Reference
    Resource

   Suppose a COPY request is submitted to the following collection, with
   the members shown:

   /MyCollection/
        (non-reference resource) diary.html
        (redirect reference resource) nunavut with target
                                   /Someplace/nunavut.map

    >> Request:

   COPY /MyCollection/ HTTP/1.1
   Host: www.svr.com
   Depth: infinity
   Destination: http://www.svr.com/OtherCollection/

    >> Response:

   HTTP/1.1 207 Multi-Status



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   Content-Type: text/xml; charset="utf-8"
   Content-Length: xxx

   <?xml version="1.0" encoding="utf-8" ?>
   <D:multistatus xmlns:D="DAV:">
     <D:response>
     <D:href>http://www.svr.com/MyCollection/nunavut</D:href>
     <D:status>HTTP/1.1 302 Found</D:status>
     <D:prop>
       <D:location>
         <D:href>http://www.svr.com//Someplace/nunavut.map</D:href>
       </D:location>
       <D:resourcetype><D:redirectref/></D:resourcetype>
     </D:prop>
     </D:response>
   </D:multistatus>

   In this case, since /MyCollection/nunavut is a redirect reference
   resource, the COPY operation was only a partial success.  The
   redirect reference resource was not copied, but a 302 response was
   returned for it.  So the resulting collection is as follows:

   /OtherCollection/
         (non-reference resource) diary.html


7.6 Example: LOCK on a Collection That Contains a Redirect Reference
    Resource

   Suppose a LOCK request is submitted to the following collection, with
   the members shown:

   /MyCollection/
        (non-reference resource) diary.html
        (redirect reference resource) nunavut

    >> Request:

   LOCK /MyCollection/ HTTP/1.1
   Host: www.svr.com
   Content-Type: text/xml
   Content-Length: nnnn
   Authorizaton: Digest username="jas",
      realm=jas@webdav.sb.aol.com, nonce=". . . ",
      uri="/MyCollection/tuva",
      response=". . . ", opaque=". . . "

   <?xml version="1.0" ?>



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   <D:lockinfo xmlns:D="DAV:">
     <D:lockscope><D:exclusive/></D:lockscope>
     <D:locktype><D:write/></D:locktype>
     <D:owner>
       <D:href>http://www.svr.com/~jas/contact.html</D:href>
     </D:owner>
   </D:lockinfo>

    >> Response:

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

   <?xml version="1.0" ?>
   <D:multistatus xmlns:D="Dav:">
     <D:response>
       <D:href>http://www.svr.com/MyCollection/</D:href>
       <D:propstat>
         <D:prop><D:lockdiscovery/></D:prop>
         <D:status>HTTP/1.1 424 Failed Dependency</D:status>
       </D:propstat>
     </D:response>
     <D:response>
       <D:href>http://www.svr.com/MyCollection/diary.html</D:href>
       <D:status>HTTP/1.1 424 Failed Dependency</D:status>
     </D:response>
     <D:response>
       <D:href>http://www.svr.com/MyCollection/nunavut</D:href>
       <D:status>HTTP/1.1 302 Found</D:status>
       <D:prop>
         <D:location>
           <D:href>http://www.inac.gc.ca/art/inuit/</D:href>
         </D:location>
         <D:resourcetype><D:redirectref/></D:resourcetype>
       </D:prop>
     </D:response>
   </D:multistatus>

   The server returns a 302 response code for the redirect reference
   resource in the collection.  Consequently, neither the collection nor
   any of the resources identified by its internal member URIs were
   locked. A referencing-aware client can submit a separate LOCK request
   to the URI in the DAV:location pseudo-property returned for the
   redirect reference resource, and can resubmit the LOCK request with
   the Apply-To-Redirect-Ref header to the collection.  At that point
   both the reference resource and its target resource will be locked
   (as well as the collection and all the resources identified by its



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   other members).


















































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8. Operations on Targets of Redirect Reference Resources

   Operations on targets of redirect reference resources have no effect
   on the reference resource.















































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9. Relative URIs in DAV:reftarget

   The URI in the href in a DAV:reftarget property MAY be a relative
   URI. In this case, the base URI to be used for resolving the relative
   URI to absolute form is the URI used in the HTTP message to identify
   the redirect reference resource to which the DAV:reftarget property
   belongs.

   When DAV:reftarget occurs in the body of a MKRESOURCE request, the
   base URI is constructed as follows: Its scheme component is "http",
   its authority component is the value of the Host header in the
   request, and its path component is the Request-URI in the request.
   See Section 5 of [RFC2396] for a discussion of relative URI
   references and how to resolve them.

   When DAV:reftarget appears in the context of a Multi-Status response,
   it is in a DAV:response element that contains a single DAV:href
   element. The value of this DAV:href element serves as the base URI
   for resolving a relative URI in DAV:reftarget.  The value of DAV:href
   may itself be relative, in which case it must be resolved first in
   order to serve as the base URI for the relative URI in DAV:reftarget.
   If the DAV:href element is relative, its base URI is constructed from
   the scheme component "http", the value of the Host header in the
   request, and the request-URI.

9.1 Example: Resolving a Relative URI in a MKRESOURCE Request

    >> Request:

   MKRESOURCE /north/inuvik HTTP/1.1
   Host: www.somehost.edu
   Content-Type: text/xml; charset="utf-8"
   Content-Length: xxx

   <?xml version="1.0" encoding="utf-8" ?>
   <D:propertyupdate xmlns:D="DAV:">
     <D:set>
       <D:prop>
         <D:resourcetype><D:redirectref/></D:resourcetype>
         <D:reftarget>
           <D:href>mapcollection/inuvik.gif</D:href>
         </D:reftarget>
       </D:prop>
     </D:set>
   </D:propertyupdate>

    >> Response:




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   HTTP/1.1 201 Created

   In this example, the base URI is http://www.somehost.edu/north/
   inuvik. Then, following the rules in [RFC2396] Section 5, the
   relative URI in DAV:reftarget resolves to the absolute URI http://
   www.somehost.edu/north/mapcollection/inuvik.gif.

9.2 Example: Resolving a Relative URI in a Multi-Status Response

    >> Request:

   PROPFIND /geog/ HTTP/1.1
   Host: www.xxsvr.com
   Apply-To-Redirect-Ref:
   Depth: 1
   Content-Type: text/xml
   Content-Length: nnn

   <?xml version="1.0" ?>
   <D:propfind xmlns:D="DAV:">
     <D:prop>
       <D:resourcetype/>
       <D:reftarget/>
     </D:prop>
   </D:propfind>

    >> Response:

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

   <?xml version="1/0" ?>
   <D:multistatus xmlns:D="DAV:">
     <D:response>
       <D:href>/geog/</D:href>
       <D:propstat>
         <D:prop>
           <D:resourcetype><D:collection/></D:resourcetype>
         </D:prop>
         <D:status>HTTP/1.1 200 OK</D:status>
       </D:propstat>
       <D:propstat>
         <D:prop><D:reftarget/></D:prop>
         <D:status>HTTP/1.1 404 Not Found</D:status>
       </D:propstat>
     </D:response>
     <D:response>



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       <D:href>/geog/stats.html</D:href>
       <D:propstat>
         <D:prop>
           <D:resourcetype><D:redirectref/></D:resourcetype>
           <D:reftarget>
             <D:href>statistics/population/1997.html</D:href>
           </D:reftarget>
         </D:prop>
       <D:status>HTTP/1.1 200 OK</D:status>
       </D:propstat>
     </D:response>
   </D:multistatus>

   In this example, the relative URI statistics/population/1997.html is
   returned as the value of reftarget for the reference resource
   identified by href /geog/stats.html.  The href is itself a relative
   URI, which resolves to http://www.xxsrv.com/geog/stats.html.  This is
   the base URI for resolving the relative URI in reftarget.  The
   absolute URI of reftarget is http://www.xxsrv.com/geog/statistics/
   population/1997.html.































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10. Redirect References to Collections

   In a Request-URI /segment1/segment2/segment3, any of the three
   segments may identify a redirect reference resource.  (See [RFC2396],
   Section 3.3, for definitions of "path" and "segment".)  If any
   segment in a Request- URI identifies a redirect reference resource,
   the response is a 302. The value of the Location header in the 302
   response is as follows:

   The leftmost path segment of the request-URI that identifies a
   redirect reference resource, together with all path segments and
   separators to the left of it, is replaced by the value of the
   redirect reference resource's DAV:reftarget property (resolved to an
   absolute URI).  The remainder of the request-URI is concatenated to
   this path.

   Note: If the DAV:reftarget property ends with a "/" and the remainder
   of the Request-URI is non-empty (and therefore must begin with a "/
   "), the final "/" in the DAV:reftarget property is dropped before the
   remainder of the Request-URI is appended.

   Consider Request-URI /x/y/z.html.  Suppose that /x/ is a redirect
   reference resource whose target resource is collection /a/, which
   contains redirect reference resource y whose target resource is
   collection /b/, which contains redirect reference resource z.html
   whose target resource is /c/d.html.

   /x/y/z.html
       |
       | /x -> /a
       |
       v
   /a/y/z.html
       |
       | /a/y -> /b
       |
       v
   /b/z.html
       |
       | /b/z.html -> /c/d.html
       |
       v
   /c/d.html

   In this case the client must follow up three separate 302 responses
   before finally reaching the target resource.  The server responds to
   the initial request with a 302 with Location: /a/y/z.html, and the
   client resubmits the request to /a/y/z.html.  The server responds to



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   this request with a 302 with Location: /b/z.html, and the client
   resubmits the request to /b/z.html.  The server responds to this
   request with a 302 with Location: /c/d.html, and the client resubmits
   the request to /c/d.html.  This final request succeeds.















































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11. Headers

11.1 Redirect-Ref Response Header

   Redirect-Ref = "Redirect-Ref:"

   The Redirect-Ref header is used in all 302 responses from redirect
   reference resources.  Its presence informs reference-aware clients
   that the response is not a plain HTTP/1.1 redirect, but is a response
   from a redirect reference resource.

11.2 Apply-To-Redirect-Ref Request Header

   Apply-To-Redirect-Ref = "Apply-To-Redirect-Ref" ":"

   The optional Apply-To-Redirect-Ref header can be used on any request
   to a redirect reference resource.  When it is used, the request MUST
   be applied to the reference resource itself, and a 302 response MUST
   NOT be returned.

   If the Apply-To-Redirect-Ref header is used on a request to any other
   sort of resource besides a redirect reference resource, the server
   SHOULD ignore it.




























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12. Properties

12.1 reftarget Property

   Name: reftarget

   Namespace: DAV:

   Purpose: A property of redirect reference resources that provides an
      efficient way for clients to discover the URI of the target
      resource.  This is a read-only property after its initial
      creation. Its value can only be set in a MKRESOURCE request.

   Value: href containing the URI of the target resource.  This value
      MAY be a relative URI.  The reftarget property can occur in the
      entity bodies of MKRESOURCE requests and of responses to PROPFIND
      requests.


   <!ELEMENT reftarget href >


12.2 location Pseudo-Property

   Name: location

   Namespace: DAV:

   Purpose: For use with 302 (Found) response codes in Multi-Status
      responses.  It contains the absolute URI of the temporary location
      of the resource.  In the context of redirect reference resources,
      this value is the absolute URI of the target resource.  It is
      analogous to the Location header in HTTP 302 responses defined in
      [RFC2616] Section 10.3.3 "302 Found."  Including the location
      pseudo-property in a Multi- Status response requires an extension
      to the syntax of the DAV:response element defined in [RFC2518],
      which is defined in Section 14 below.  This pseudo-property is not
      expected to be stored on the reference resource. It is modeled as
      a property only so that it can be returned inside a DAV:prop
      element in a Multi-Status response.

   Value: href containing the absolute URI of the target resource.


   <!ELEMENT location href >






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13. XML Elements

13.1 redirectref XML Element

   Name: redirectref

   Namespace: DAV:

   Purpose: Used as the value of the DAV:resourcetype property to
      specify that the resource type is a redirect reference resource.


   <!ELEMENT redirectref EMPTY >






































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14. Extensions to the DAV:response XML Element for Multi-Status
    Responses

   As described in Section 7, the DAV:location pseudo-property and the
   DAV:resourcetype property may be returned in the DAV:response element
   of a 207 Multi-Status response, to allow clients to resubmit their
   requests to the target resource of a redirect reference resource.

   Whenever these properties are included in a Multi-Status response,
   they are placed in a DAV:prop element associated with the href to
   which they apply.  This structure provides a framework for future
   extensions by other standards that may need to include additional
   properties in their responses.

   Consequently, the definition of the DAV:response XML element changes
   to the following:

   <!ELEMENT response (href, ((href*, status, prop?) | (propstat+)),
   responsedescription?) >
































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15. Capability Discovery

   Sections 9.1 and 15 of [RFC2518] describe the use of compliance
   classes with the DAV header in responses to OPTIONS, to indicate
   which parts of the WebDAV Distributed Authoring protocols the
   resource supports. This specification defines an OPTIONAL extension
   to [RFC2518].  It defines a new compliance class, called
   redirectrefs, for use with the DAV header in responses to OPTIONS
   requests.  If a resource does support redirect references, its
   response to an OPTIONS request may indicate that it does, by listing
   the new redirectrefs compliance class in the DAV headerand by listing
   the MKRESOURCE method as one it supports.

   When responding to an OPTIONS request, any type of resource can
   include redirectrefs in the value of the DAV header.  Doing so
   indicates that the server permits a redirect reference resource at
   the request URI.

15.1 Example: Discovery of Support for Redirect Reference Resources

    >> Request:

   OPTIONS /somecollection/someresource HTTP/1.1
   HOST: somehost.org

    >> Response:

   HTTP/1.1 200 OK
   Date: Tue, 20 Jan 1998 20:52:29 GMT
   Connection: close
   Accept-Ranges: none
   Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE,
   MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, MKRESOURCE
   DAV: 1, 2, redirectrefs

   The DAV header in the response indicates that the resource /
   somecollection/someresource is level 1 and level 2 compliant, as
   defined in [RFC2518].  In addition, /somecollection/someresource
   supports redirect reference resources.  The Allow header indicates
   that MKRESOURCE requests can be submitted to /somecollection/
   someresource. The Public header shows that other Request-URIs on the
   server support additional methods.









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16. Security Considerations

   This section is provided to make applications that implement this
   protocol aware of the security implications of this protocol.

   All of the security considerations of HTTP/1.1 and the WebDAV
   Distributed Authoring Protocol specification also apply to this
   protocol specification.  In addition, redirect reference resources
   introduce several new security concerns and increase the risk of some
   existing threats.  These issues are detailed below.

16.1 Privacy Concerns

   By creating redirect reference resources on a trusted server, it is
   possible for a hostile agent to induce users to send private
   information to a target on a different server.   This risk is
   mitigated somewhat, since clients are required to notify the user of
   the redirection for any request other than GET or HEAD. (See
   [RFC2616], Section 10.3.3 302 Found.)

16.2 Redirect Loops

   Although redirect loops were already possible in HTTP 1.1, the
   introduction of the MKRESOURCE method creates a new avenue for
   clients to create loops accidentally or maliciously.  If the
   reference resource and its target are on the same server, the server
   may be able to detect MKRESOURCE requests that would create loops.
   See also [RFC2616], Section 10.3 "Redirection 3xx."

16.3 Redirect Reference Resources and Denial of Service

   Denial of service attacks were already possible by posting URLs that
   were intended for limited use at heavily used Web sites.  The
   introduction of MKRESOURCE creates a new avenue for similar denial of
   service attacks.  Clients can now create redirect reference resources
   at heavily used sites to target locations that were not designed for
   heavy usage.

16.4 Revealing Private Locations

   There are several ways that redirect reference resources may reveal
   information about collection structures.  First, the DAV:reftarget
   property of every redirect reference resource contains the URI of the
   target resource.  Anyone who has access to the reference resource can
   discover the collection path that leads to the target resource.   The
   owner of the target resource may have wanted to limit knowledge of
   this collection structure.




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   Sufficiently powerful access control mechanisms can control this risk
   to some extent.  Property-level access control could prevent users
   from examining the DAV:reftarget property.  (The Location header
   returned in responses to requests on redirect reference resources
   reveals the same information, however.)  In some environments, the
   owner of a resource might be able to use access control to prevent
   others from creating references to that resource.

   This risk is no greater than the similar risk posed by HTML links.










































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17. Internationalization Considerations

   This specification follows the practices of [RFC2518] in encoding all
   human-readable content using XML [XML] and in the treatment of names.
   Consequently, this specification complies with the IETF Character Set
   Policy [RFC2277].

   WebDAV applications MUST support the character set tagging, character
   set encoding, and the language tagging functionality of the XML
   specification.  This constraint ensures that the human-readable
   content of this specification complies with [RFC2277].

   As in [RFC2518], names in this specification fall into three
   categories: names of protocol elements such as methods and headers,
   names of XML elements, and names of properties.  Naming of protocol
   elements follows the precedent of HTTP, using English names encoded
   in USASCII for methods and headers.  The names of XML elements used
   in this specification are English names encoded in UTF-8.

   For error reporting, [RFC2518] follows the convention of HTTP/1.1
   status codes, including with each status code a short, English
   description of the code (e.g., 423 Locked).  Internationalized
   applications will ignore this message, and display an appropriate
   message in the user's language and character set.

   This specification introduces no new strings that are displayed to
   users as part of normal, error-free operation of the protocol.

   For rationales for these decisions and advice for application
   implementors, see [RFC2518].





















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18. IANA Considerations

   All IANA considerations mentioned in [RFC2518] also apply to this
   document.















































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19. Acknowledgements

   This draft has benefited from thoughtful discussion by Jim Amsden,
   Peter Carlson, Steve Carter, Tyson Chihaya, Ken Coar, Ellis Cohen,
   Bruce Cragun, Spencer Dawkins, Mark Day, Rajiv Dulepet, David Durand,
   Roy Fielding, Yaron Goland, Fred Hitt, Alex Hopmann, James Hunt,
   Marcus Jager, Chris Kaler, Manoj Kasichainula, Rohit Khare, Daniel
   LaLiberte, Steve Martin, Larry Masinter, Jeff McAffer, Joe Orton,
   Surendra Koduru Reddy, Juergen Reuter, Max Rible, Sam Ruby, Bradley
   Sergeant, Nick Shelness, John Stracke, John Tigue, John Turner, Kevin
   Wiggen, and others.








































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Normative References

   [RFC2277]  Alvestrand, H., "IETF Policy on Character Sets and
              Languages", BCP 18, RFC 2277, January 1998.

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

   [RFC2396]  Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
              Resource Identifiers (URI): Generic Syntax", RFC 2396,
              August 1998.

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

   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [XML]      Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler,
              "Extensible Markup Language (XML) 1.0 (2nd ed)", W3C
              REC-xml, October 2000, <http://www.w3.org/TR/2000/
              REC-xml-20001006>.

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Authors' Addresses

   J. Slein
   Xerox Corporation
   800 Phillips Road, 105-50C
   Webster, NY  14580

   EMail: jslein@crt.xerox.com


   Jim Whitehead
   UC Santa Cruz, Dept. of Computer Science
   1156 High Street
   Santa Cruz, CA  95064
   US

   EMail: ejw@cse.ucsc.edu


   J. Davis
   CourseNet Systems
   170 Capp Street
   San Francisco, CA  94110

   EMail: jrd3@alum.mit.edu


   G. Clemm
   Rational Software Corporation
   20 Maguire Road
   Lexington, MA  02173-3104

   EMail: geoffrey.clemm@us.ibm.com






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   C. Fay
   FileNet Corporation
   3565 Harbor Boulevard
   Costa Mesa, CA  92626-1420

   EMail: cfay@filenet.com


   J. Crawford
   IBM Research
   P.O. Box 704
   Yorktown Heights, NY  10598

   EMail: ccjason@us.ibm.com


   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/

























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Appendix A. Changes to the WebDAV Document Type Definition

   <!-- XML Elements from Section 13 -->
   <!ELEMENT redirectref EMPTY >
   <!--  -->Property Elements from Section 12 -->
   <!ELEMENT reftarget href>
   <!ELEMENT location href>
   <!-- Changes to the DAV:response Element from Section 14 -->
   <!ELEMENT response (href, ((href*, status, prop?) | (propstat+)),
   responsedescription?) >









































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Appendix B. Change Log (to be removed by RFC Editor before publication)

B.1 Since draft-ietf-webdav-redirectref-protocol-02

   Julian Reschke takes editorial role (added to authors list). Cleanup
   XML indentation. Start adding all unresolved last call issues. Update
   some author's contact information. Update references, split into
   "normative" and "informational". Remove non-RFC2616 headers
   ("Public") from examples. Fixed width problems in artwork. Start
   resolving editorial issues.

B.2 Since draft-ietf-webdav-redirectref-protocol-03

   Added Joe Orton and Juergen Reuter to Acknowledgements section. Close
   more editorial issues. Remove dependencies on BIND spec.




































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Appendix C. Resolved issues (to be removed by RFC Editor before
            publication)

   Issues that were either rejected or resolved in this version of this
   document.

C.1 lc-07-bind

   Type: change

   [3]

   reuterj@ira.uka.de (2000-02-07): Abstract should discuss only
   redirect references, not bindings. Expand discussion of redirect
   references.

   Resolution: Abstract will discuss only redirect references. See also
   issue 34.

C.2 lc-08-bind

   Type: change

   [4]

   reuterj@ira.uka.de (2000-02-07): Get rid of cross-references to the
   binding spec: in the abstract, in the introduction, in the definition
   of Reference Resource.

   Resolution: Cross-references to bindings will be removed. See also
   issue 34.

C.3 lc-34-bind

   Type: change

   [5]

   yarong@Exchange.Microsoft.com (2000-02-11): NoBind: Remove all
   cross-references to the binding spec. Prefer also removing all
   mention of bindings.

   Resolution: Agreed. See also issues 7, 8, 14

C.4 lc-83-bind

   Type: change




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   [6]

   reuterj@ira.uka.de (2000-02-22): References: Get rid of the reference
   to the bindings spec.

   Resolution: Agreed.

C.5 lc-12-bind

   Type: change

   [7]

   reuterj@ira.uka.de (2000-02-07): First 3 paragraphs of Introduction
   are identical to those in binding spec. Make sure that any changes
   made there are also incorporated here.

   Resolution: These paragraphs will change as necessary to make the
   redirect spec completely independent of the rest of WebDAV.

C.6 lc-35-bind

   Type: change

   [8]

   yarong@Exchange.Microsoft.com (2000-02-11): ReallyNoBind: Remove
   paras. 6 and 8 from Intro.

   Resolution: Agreed. See also issue 14.

C.7 lc-01-body

   Type: change

   [9]

   joe@orton.demon.co.uk (2000-01-26): Entity Bodies for Redirect
   References: Clarify: Are there 2 resources, one that redirects and
   one that responds with its own entity body? Clarify: What is the
   effect of PUT for a URI that currently maps to a redirect reference?

   Resolution: Redirect resource MUST NOT have a body. See also issue
   last call issue 23.

C.8 lc-14-bind

   Type: change



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   [10]

   reuterj@ira.uka.de (2000-02-07): Limit the discussion of bindings to
   just what is needed to understand the differences from redirect
   references. Maybe the paragraph in the Intro that starts "By
   contrast, a BIND request . . ." is all that is needed.

   Resolution: Get rid of discussion of bindings altogether. See also
   issue 34, 35.

C.9 lc-15-direct-ref

   Type: change

   [11]

   reuterj@ira.uka.de (2000-02-07): Don't define Direct Reference
   Resource, since direct references are out of scope. (If you do keep
   the definition, say explicitly that a direct reference resource is a
   type of reference resource.)

   Resolution: Remove definition of Direct Reference Resource. See also
   issue 39.

C.10 lc-39-no-reference-or-direct-resource

   Type: change

   [12]

   yarong@Exchange.Microsoft.com (2000-02-11):
   NoReferenceOrDirectResource: Remove the definitions of "Reference"
   and "Direct Reference Resource." Change the definition of "Redirect
   Reference Resource" to be: Redirect Resource: A resource created to
   redirect all requests made to it, using 302 (Found), to a defined
   target resource.

   julian.reschke@greenbytes.de (2003-07-27): (Rename from "redirect
   reference resource" to "redirect resource" delayed for now).

   Resolution: Agreed. See also issue 15.

C.11 lc-40-direct

   Type: change

   [13]




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   yarong@Exchange.Microsoft.com (2000-02-11): Assorted changes to
   Section 4, para 2 to get rid of the word "forward" and the word
   "server" and remove comparison with direct references.

   Resolution: See also issue 33 (forward). See also issue 36 (server).
   Remove discussion of direct references.

C.12 lc-45-apply-to-rr

   Type: change

   [14]

   yarong@Exchange.Microsoft.com (2000-02-11): Suggested replacement
   text for this paragraph, which briefly introduces
   Apply-To-Redirect-Ref. Includes a note that even with this header,
   the response may be a 302.

   Resolution: See issue 19 for replacement text. Disagree. Redirect
   reference will never respond to Apply-To-RR with 302.

C.13 lc-01A-body

   Type: change

   [15]

   joe@orton.demon.co.uk (2000-01-26): In the definition of MKRESOURCE,
   "Body" needs to be defined or else terminology changed.

   Resolution: We will use MKREF instead of MKRESOURCE.

C.14 lc-31-MKCOL

   Type: edit

   [16]

   reuterj@ira.uka.de (2000-02-07): Section 6, para on MKRESOURCE and
   MKCOL is obvious and doesn't need to be stated. Maybe show in an
   example.

   Resolution: Agreed. See also issue 48.

C.15 lc-67-redirectref

   Type: change




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   [17]

   reuterj@ira.uka.de (2000-02-14): 7.4: The explanation should not
   contrast displaying the properties of the redirect ref with
   displaying the properties of its target, but with returning a 302.

   Resolution: Revise as recommended.

C.16 lc-54-s10

   Type: change

   [18]

   yarong@Exchange.Microsoft.com (2000-02-11): The Note: in section 10
   has the same problem pointed out in Bindings.NoSlash and needs to be
   fixed. It contradicts RFC 2518 and 2616, which both assume that a URL
   and the same URL + "/" may map to different resources.

   Resolution: Agreed in mailing list discussions that no change is
   needed.

C.17 lc-78-directory

   Type: change

   [19]

   reuterj@ira.uka.de (2000-02-22): Section 16.4: Change "directory" to
   "collection". Not new to this protocol. Holds for any protocol that
   has hierarchical access paths.

C.18 lc-82-iana

   Type: change

   [20]

   reuterj@ira.uka.de (2000-02-22): Section 18: Just reference [WebDAV]
   and say this protocol does not introduce any new considerations.

   Resolution: Simplify, then resolve issue 55.









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Appendix D. Open issues (to be removed by RFC Editor before publication)

D.1 lc-85-301

   Type: change

   ejw@cse.ucsc.edu (2000-01-03): Support creation of other than 302
   redirects, especially 301.

D.2 lc-38-not-hierarchical

   Type: change

   [21]

   yarong@Exchange.Microsoft.com (2000-02-11): Not Hierarchical: The
   first sentence of the second paragraph of the introduction of the
   redirect spec asserts that the URIs of WebDAV compliant resources
   match to collections. The WebDAV standard makes no such requirement.
   I therefore move that this sentence be stricken.

   Resolution: State the more general HTTP rationale first (alternative
   names for the same resource), then introduce the collection hierarchy
   rationale, which applies only if you are in a WebDAV-compliant space.

D.3 lc-36-server

   Type: change

   [22]

   yarong@Exchange.Microsoft.com (2000-02-11): Servers: Replace "server"
   with "unrelated system" throughout.

   Resolution: Try replacing "server" with "host" in some contexts,
   rephrasing in passive voice in others. See also issue 40.

D.4 lc-33-forwarding

   Type: change

   [23]

   yarong@Exchange.Microsoft.com (2000-02-11): Forwarding: Replace
   "forward" with "redirect" throughout.

   Resolution: Use "redirect" for the behavior redirect resources do
   exhibit. Use "forward" for the contrasting behavior (passing a method



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   on to the target with no client action needed). Define these two
   terms. See also issue 40.

D.5 lc-56-notjusthttp

   Type: change

   [24]

   yarong@Exchange.Microsoft.com (2000-02-11): Make it clear in examples
   and text that the redirection URI could be non-HTTP.

   Resolution: We agree that it is possible to create redirect
   references to non-HTTP resources. Add example.

D.6 lc-37-integrity

   Type: change

   [25]

   yarong@Exchange.Microsoft.com (2000-02-11): Integrity: Intro, para 7
   "Servers are not required to enforce the integrity of redirect
   references." Integrity is not defined. Replace with something
   clearer.

   Resolution: Rewrite to say that the server MUST NOT update the target
   See also issue 6.

D.7 3-terminology-redirectref

   Type: change

   [26]

   julian.reschke@greenbytes.de (2003-07-27): Consider global rename of
   "redirect reference resource" to "redirect resource".

D.8 lc-43-webdav

   Type: change

   [27]

   yarong@Exchange.Microsoft.com (2000-02-11): Get rid of the
   DAV:reftarget property.

   Resolution: DAV:reftarget is readonly and is present only for



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   redirect references that are also WebDAV resources. We'll also have a
   method for setting target; Redirect-Ref header (returned on all 302
   responses) will have the target as its value. See also issue 6, 17,
   50.

D.9 lc-19-direct-ref

   Type: change

   [28]

   reuterj@ira.uka.de (2000-02-07): Section 4, para 5 and Section 6,
   para 3 discussions of the Apply-to-Redirect-Ref header make it sound
   as if we are specifying direct reference behavior.

   Resolution: Change these passages so that the contrast is between
   applying the method to the redirect reference and responding with a
   302.

D.10 lc-04-standard-data-container

   Type: change

   [29]

   joe@orton.demon.co.uk (2000-01-26): "Standard data container" needs
   to be defined in the context of MKRESOURCE

   Resolution: Not relevant once we switch to MKREF.

D.11 lc-05-standard-data-container

   Type: change

   [30]

   joe@orton.demon.co.uk (2000-01-26): Inconsistency about whether a
   "standard data container" can be created with MKRESOURCE or not.

   Resolution: Not relevant once we switch to MKREF.

D.12 lc-20-intro-mkresource

   Type: change

   [31]

   reuterj@ira.uka.de (2000-02-07): Section 5: Start with "The new



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   MKRESOURCE method" to make it clear that it is being introduced for
   the first time here.

   Resolution: Say "The MKREF method defined normatively here . . ."

D.13 lc-22-coll

   Type: change

   [32]

   reuterj@ira.uka.de (2000-02-07): Inconsistency about whether
   collections can be created with MKRESOURCE.

   Resolution: Not relevant for MKREF.

D.14 lc-25-atomic

   Type: change

   [33]

   reuterj@ira.uka.de (2000-02-07): Is MKRESOURCE atomic as viewed by a
   client? Can another client access the new resource's properties
   before they have been fully initialized? Maybe the MKRESOURCE request
   should let the client ask for it to be atomic.

   Resolution: No longer relevant once we switch to MKREF with no
   request body.

D.15 lc-41-no-webdav

   Type: change

   [34]

   yarong@Exchange.Microsoft.com (2000-02-11): Make redirect references
   independent of the rest of WebDAV. The creation method for redirect
   references shouldn't require an XML request body.

   Resolution: We will make redirect references independent of the rest
   of WebDAV. MKREF will not have an XML request body.

D.16 lc-42-no-webdav

   Type: change

   [35]



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   yarong@Exchange.Microsoft.com (2000-02-11): Use a creation method
   that creates only redirect references. The MKRESOURCE method hinders
   experiment because a user of a server who wishes to add support for
   the creation of a new resource type can't simply throw in another
   Apache module and allow it to provide the code for the new resource
   type. They have to find the code used for MKRESOURCE and change it to
   support the new resource type.

   Resolution: We will replace MKRESOURCE with MKREF, which creates only
   redirect reference resources.

D.17 lc-58-update

   Type: change

   [36]

   yarong@Exchange.Microsoft.com (2000-02-11): There needs to be a way
   to update the target of a redirect reference.

   Resolution: Agreed. See also issues 6, 43.

D.18 lc-23-body

   Type: change

   [37]

   reuterj@ira.uka.de (2000-02-07): Section 5.1: Get rid of the
   statement that the body of the resource is empty (PostConditions). It
   would be good if the response to GET included a response body that
   could be shown to a user by a client that doesn't do automatic
   redirection. There is a related problem in Section 6 on PUT. It is
   wrong to assume that what is PUT to a resource is what GET will
   return. In Section 6, say "A PUT with Apply-To-RR MAY contain a
   request body. The semantics of the request body is out of scope for
   this specification..." Also fix the discussion of example 6.2.

   Resolution: Redirect references cannot have bodies. GET with
   Apply-To-RR MUST fail with 403. PUT with Apply-To-RR MUST fail with
   403. See also issue 1.

D.19 lc-24-properties

   Type: change

   [38]




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   reuterj@ira.uka.de (2000-02-07): Section 5.1: Replace the sentence
   "The properties of the new resource are as specified by the
   DAV:propertyupdate request body, using PROPPATCH semantics" with the
   following: "The MKRESOURCE request MAY contain a DAV:propertyupdate
   request body to initialize resource properties. Herein, the semantics
   is the same as when sending a MKRESOURCE request without a request
   body, followed by a PROPPATCH with the DAV:propertyupdate request
   body."

   Resolution: No longer relevant once we switch to MKREF with no
   request body.

D.20 lc-47-207

   Type: change

   [39]

   yarong@Exchange.Microsoft.com (2000-02-11): In line with his wish to
   get rid of the request message body of MKRESOURCE, 207 would not be
   an appropriate response code. The description of 409 might lead
   someone to believe that you can't create redirect references outside
   of WebDAV namespaces. Suggests a different description.

   Resolution: No longer relevant - MKREF can't get a 207 response.
   Revise to make it clear that the first condition will only occur in
   WebDAV-compliant namespaces.

D.21 lc-48-s6

   Type: change

   [40]

   yarong@Exchange.Microsoft.com (2000-02-11): Replace all of section 6
   with just this: A redirect resource, upon receiving a request without
   an Apply-To-Redirect-Ref header, MUST respond with a 302 (Found)
   response. The 302 (Found) response MUST include a location header
   identifying the target and a Redirect-Ref header. If a redirect
   resource receives a request with an Apply-To-Redirect-Ref header then
   the redirect reference resource MUST apply the method to itself
   rather than blindly returning a 302 (Found) response.

   Resolution: Keep a summary along the lines of Yaron's proposal (don't
   use the word "blindly"). Keep the bullets detailing the headers to be
   returned. Delete the rest, including the examples. See also issue 28,
   29, 30, 31, 32.




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D.22 lc-28-lang

   Type: edit

   [41]

   reuterj@ira.uka.de (2000-02-07): Section 6: Get rid of the sentence
   "A reference-aware WebDAV client can act on this response in one of
   two ways." A client can act on the response in any way it wants.

   Resolution: Agreed. See also issue 48.

D.23 lc-29-lang

   Type: edit

   [42]

   reuterj@ira.uka.de (2000-02-07): Section 6, para 4: Obvious, doesn't
   need to be stated. Maybe note in an example.

   Resolution: Agreed. See also issue 48.

D.24 lc-49-put

   Type: change

   [43]

   yarong@Exchange.Microsoft.com (2000-02-11): Remove the last sentence
   of Example 6.2, which says that PUT replaces the reference with a
   different resource.

   Resolution: No longer relevant. Deleted this example in response to
   issue 48.

D.25 lc-44-pseudo

   Type: change

   [44]

   yarong@Exchange.Microsoft.com (2000-02-11): Instead of adding an
   optional prop XML element to the response element in 207 responses,
   define a new location XML element and a new refresource XML element.

   Resolution: Agree to define new XML elements that are not
   pseudo-properties. Disagreement about whether refresource is needed.



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   See issue 61.

D.26 lc-61-pseudo

   Type: change

   [45]

   reuterj@ira.uka.de (2000-02-14): Section 7: It doesn't make sense to
   ask future editors of RFC 2518 to define DAV:location with the
   semantics it has here. RFC 2518 should provide the information in the
   Location header somehow in multistatus responses, but not by using
   properties.

   Resolution: Define an XML element for location that is not a
   pseudo-property. We'll keep the recommendation that RFC 2518 add this
   for 302 responses. See also issue 44.

D.27 lc-60-ex

   Type: change

   [46]

   reuterj@ira.uka.de (2000-02-14): Section 7, para 3: Make it clear
   that these are just examples of client behavior, and are not meant to
   limit the client's behavior to these options.

   Resolution: Agreed to delete this paragraph. Continue discussion of
   what information should be returned with 302 in multistatus. Just
   location? Also redirectref?

D.28 lc-62-oldclient

   Type: change

   [47]

   reuterj@ira.uka.de (2000-02-14): Section 7: It's too strong to claim
   that non-referencing clients can't process 302 responses occurring in
   Multi-Status responses. They just have an extra round trip for each
   302.

   Resolution: Remove last sentence of the paragraph that recommends
   changes to RFC 2518.

D.29 lc-63-move




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   Type: change

   [48]

   reuterj@ira.uka.de (2000-02-14): Section 7.1: Is MOVE atomic from the
   perspective of a client? Agrees that there should be no 302s for
   member redirect references, but finds the rationale dubious.

   Resolution: Remove 7.1. Reword 7.2 to avoid concerns with "poses
   special problems" and "due to atomicity".

D.30 lc-06-reftarget-relative

   Type: change

   [49]

   joe@orton.demon.co.uk (2000-01-29): Why does the spec talk about
   relative URIs in DAV:reftarget in MKRESOURCE requests? Is the server
   required to resolve the relative URI and store it as absolute? Is the
   server required to keep DAV:reftarget pointing to the target resource
   as the reference / target move, or is DAV:reftarget a dead property?

   Resolution: DAV:reftarget is readonly and present only on redirect
   references that are also WebDAV resources. Add a method for setting
   the target. Change definition of Redirect-Ref header so that it has
   the target as its value (comes back on all 302 responses). Server
   MUST store the target exactly as it is set. It MUST NOT resolve
   relatives to absolutes and MUST NOT update if target resource moves.
   See also issue 17, 43, 50, 57

D.31 lc-57-noautoupdate

   Type: change

   [50]

   yarong@Exchange.Microsoft.com (2000-02-11): Add language to forbid
   servers from automatically updating redirect resources when their
   targets move.

   Resolution: Agreed. See also issue 6.

D.32 lc-71-relative

   Type: change

   [51]



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   reuterj@ira.uka.de (2000-02-14): Section 9: Base URI should be the
   Request-URI or href minus its final segment.

   Resolution: Fix this.

D.33 lc-53-s10

   Type: change

   [52]

   yarong@Exchange.Microsoft.com (2000-02-11): The behavior described in
   this section would have a very serious impact on the efficiency of
   mapping Request-URIs to resources in HTTP request processing. Also
   specify another type of redirect resource that does not behave as in
   section 10, but instead would "expose the behavior we see today in
   various HTTP servers that allow their users to create 300 resources."
   Be sure we know what behavior will be if the redirect location is not
   an HTTP URL, but, say ftp.

   Resolution: We won't define 2 sorts of redirect references here.
   Servers SHOULD respond with 302 as described here, but if they can't
   do that, respond with 404 Not Found. (It's hard to modularize the
   behavior specified - it impacts processing Not Found cases of all
   methods, so you can't just add it to an HTTP server in a redirect ref
   module.)

D.34 lc-72-trailingslash

   Type: change

   [53]

   reuterj@ira.uka.de (2000-02-14): Section 10: Forbid DAV:reftarget
   from ending in "/"

   Resolution: Make the note warn about the possibility of two slashes
   in a row, recommend against ending target with a slash, since that
   could result in two slashes in a row.

D.35 lc-50-blindredirect

   Type: change

   [54]

   yarong@Exchange.Microsoft.com (2000-02-11): Replace current language
   explaining the purpose of the Redirect-Ref header with language that



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   simply states that it marks blind 302 responses from redirect
   resources. (Section 6.3, 11.1)

   Resolution: Section 6.3 was removed in response to issue 48. In 11.1,
   change the definition of the Redirect-Ref header to have the value of
   the target (relative URI) as its value. Then we don't need a method
   for retrieving the target's relative URI. Presence of the
   Redirect-Ref header lets the client know that the resource accepts
   Apply-To-RR header and the new method for updating target. Reject
   Yaron's suggested language, but make the above changes.

D.36 lc-74-terminology

   Type: change

   [55]

   reuterj@ira.uka.de (2000-02-14): "plain HTTP/1.1 redirect" - find
   some good name for this an use it consistently

D.37 lc-75-ignore

   Type: change

   [56]

   reuterj@ira.uka.de (2000-02-14): 11.2: "If the Apply-To-Redirect-Ref
   header is used on a request to any other sort of resource besides a
   redirect reference resource, the server SHOULD ignore it." Don't need
   to say this since HTP already says that any header that is not
   understood should be ignored.

D.38 lc-76-location

   Type: change

   [57]

   reuterj@ira.uka.de (2000-02-22): 12.2: Make DAV:location a real
   (live) property, get rid of the DAV:reftarget property

D.39 lc-79-accesscontrol

   Type: change

   [58]

   reuterj@ira.uka.de (2000-02-22): Section 16.4: "In some environments,



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   the owner of a resource might be able to use access control to
   prevent others from creating references to that resource." That would
   not be consistent with the concept of redirect references as weak
   links (e.g. think of moving a resource to a different locationo that
   is already the target of some redirection reference.

D.40 lc-80-i18n

   Type: change

   [59]

   reuterj@ira.uka.de (2000-02-22): Section 17: Could get rid of a lot
   of this section, since this protocol extends WebDAV. Just reference
   [WebDAV].

D.41 lc-55-iana

   Type: change

   [60]

   yarong@Exchange.Microsoft.com (2000-02-11): Expand the IANA section
   to list all methods, headers, XML elements, MIME types, URL schemes,
   etc., defined by the spec.

   Resolution: Agreed.
























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