draft-ietf-webdav-redirectref-protocol-13.txt   rfc4437.txt 
WEBDAV Working Group J. Whitehead Network Working Group J. Whitehead
Internet-Draft U.C. Santa Cruz Request for Comments: 4437 U.C. Santa Cruz
Expires: April 15, 2006 G. Clemm Category: Experimental G. Clemm
IBM IBM
J. Reschke, Ed. J. Reschke, Ed.
greenbytes greenbytes
October 12, 2005 March 2006
Web Distributed Authoring and Versioning (WebDAV) Redirect Reference
Resources
draft-ietf-webdav-redirectref-protocol-13
Status of this Memo
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This Internet-Draft will expire on April 15, 2006. This memo defines an Experimental Protocol for the Internet
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Discussion and suggestions for improvement are requested.
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2006).
Abstract Abstract
This specification defines redirect reference resources. A redirect This specification defines an extension to Web Distributed Authoring
reference resource is a resource whose default response is an and Versioning (WebDAV) to allow clients to author HTTP redirect
HTTP/1.1 3xx (Redirection) status code (see RFC2616, Section 10.3), reference resources whose default response is an HTTP/1.1 3xx
redirecting the client to a different resource, the target resource. (Redirection) status code. A redirect reference makes it possible to
access the target resourced indirectly through any URI mapped to the
A redirect reference makes it possible to access the target resource redirect reference resource. This specification does not address
indirectly, through any URI mapped to the redirect reference remapping of trees of resources or regular expression based
resource. There are no integrity guarantees associated with redirect redirections. There are no integrity guarantees associated with
reference resources. redirect reference resources. Other mechanisms can also be used to
achieve the same functionality as this specification. This
Editorial Note (To be removed by RFC Editor before publication) specification allows operators to experiment with this mechanism and
develop experience on what is the best approach to the problem.
Distribution of this document is unlimited. Please send comments to
the Distributed Authoring and Versioning (WebDAV) working group at
<mailto:w3c-dist-auth@w3.org>, which may be joined by sending a
message with subject "subscribe" to
<mailto:w3c-dist-auth-request@w3.org>. Discussions of the WEBDAV
working group are archived at
<http://lists.w3.org/Archives/Public/w3c-dist-auth/>.
An issues list and XML and HTML versions of this draft are available
from <http://greenbytes.de/tech/
webdav/#draft-ietf-webdav-redirectref-protocol>.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction ....................................................3
2. Notational Conventions . . . . . . . . . . . . . . . . . . . 6 2. Notational Conventions ..........................................4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Terminology .....................................................4
4. Overview of Redirect Reference Resources . . . . . . . . . . 7 4. Overview of Redirect Reference Resources ........................5
5. Operations on Redirect Reference Resources . . . . . . . . . 8 5. Operations on Redirect Reference Resources ......................6
6. MKREDIRECTREF Method . . . . . . . . . . . . . . . . . . . . 8 6. MKREDIRECTREF Method ............................................7
6.1 Example: Creating a Redirect Reference Resource with 6.1. Example: Creating a Redirect Reference Resource
MKREDIRECTREF . . . . . . . . . . . . . . . . . . . . . . 10 with MKREDIRECTREF .........................................8
7. UPDATEREDIRECTREF Method . . . . . . . . . . . . . . . . . . 10 7. UPDATEREDIRECTREF Method ........................................9
7.1 Example: Updating a Redirect Reference Resource with 7.1. Example: Updating a Redirect Reference Resource with
UPDATEREDIRECTREF . . . . . . . . . . . . . . . . . . . . 12 UPDATEREDIRECTREF .........................................10
8. Operations on Collections That Contain Redirect Reference 8. Operations on Collections That Contain Redirect
Resources . . . . . . . . . . . . . . . . . . . . . . . . . 12 Reference Resources ............................................11
8.1 Example: PROPFIND on a Collection with Redirect 8.1. Example: PROPFIND on a Collection with Redirect
Reference Resources . . . . . . . . . . . . . . . . . . . 13 Reference .................................................11
8.2 Example: PROPFIND with Apply-To-Redirect-Ref on a 8.2. Example: PROPFIND with Apply-To-Redirect-Ref on a
Collection with Redirect Reference Resources . . . . . . . 16 Collection with Redirect Reference Resources ..............13
9. Operations on Targets of Redirect Reference Resources . . . 17 9. Operations on Targets of Redirect Reference Resources ..........15
10. Relative references in DAV:reftarget . . . . . . . . . . . . 17 10. Relative References in DAV:reftarget ..........................15
10.1 Example: Resolving a Relative Reference in a 10.1. Example: Resolving a Relative Reference in a
Multi-Status Response . . . . . . . . . . . . . . . . . 18 Multi-Status Response.....................................16
11. Redirect References to Collections . . . . . . . . . . . . . 19 11. Redirect References to Collections ............................17
12. Headers . . . . . . . . . . . . . . . . . . . . . . . . . . 21 12. Headers .......................................................18
12.1 Redirect-Ref Response Header . . . . . . . . . . . . . . 21 12.1. Redirect-Ref Response Header .............................18
12.2 Apply-To-Redirect-Ref Request Header . . . . . . . . . . 21 12.2. Apply-To-Redirect-Ref Request Header .....................19
13. Redirect Reference Resource Properties . . . . . . . . . . . 21 13. Redirect Reference Resource Properties ........................19
13.1 DAV:redirect-lifetime (protected) . . . . . . . . . . . 21 13.1. DAV:redirect-lifetime (protected) ........................19
13.2 DAV:reftarget (protected) . . . . . . . . . . . . . . . 22 13.2. DAV:reftarget (protected) ................................19
14. XML Elements . . . . . . . . . . . . . . . . . . . . . . . . 22 14. XML Elements ..................................................19
14.1 redirectref XML Element . . . . . . . . . . . . . . . . 22 14.1. redirectref XML Element ..................................19
15. Extensions to the DAV:response XML Element for 15. Extensions to the DAV:response XML Element for Multi-Status
Multi-Status Responses . . . . . . . . . . . . . . . . . . . 22 Responses .....................................................20
16. Capability Discovery . . . . . . . . . . . . . . . . . . . . 22 16. Capability Discovery ..........................................20
16.1 Example: Discovery of Support for Redirect Reference 16.1. Example: Discovery of Support for Redirect
Resources . . . . . . . . . . . . . . . . . . . . . . . 23 Reference Resources ......................................20
17. Security Considerations . . . . . . . . . . . . . . . . . . 23 17. Security Considerations .......................................21
17.1 Privacy Concerns . . . . . . . . . . . . . . . . . . . . 23 17.1. Privacy Concerns .........................................21
17.2 Redirect Loops . . . . . . . . . . . . . . . . . . . . . 24 17.2. Redirect Loops ...........................................21
17.3 Redirect Reference Resources and Denial of Service . . . 24 17.3. Redirect Reference Resources and Denial of Service .......21
17.4 Revealing Private Locations . . . . . . . . . . . . . . 24 17.4. Revealing Private Locations ..............................22
18. Internationalization Considerations . . . . . . . . . . . . 24 18. Internationalization Considerations ...........................22
19. IANA Considerations . . . . . . . . . . . . . . . . . . . . 25 19. IANA Considerations ...........................................22
19.1 HTTP headers . . . . . . . . . . . . . . . . . . . . . . 25 19.1. HTTP headers .............................................22
19.1.1 Redirect-Ref . . . . . . . . . . . . . . . . . . . . 25 19.1.1. Redirect-Ref ......................................22
19.1.2 Apply-To-Redirect-Ref . . . . . . . . . . . . . . . 25 19.1.2. Apply-To-Redirect-Ref .............................23
20. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25 20. Contributors ..................................................23
21. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25 21. Acknowledgements ..............................................23
22. Normative References . . . . . . . . . . . . . . . . . . . . 26 22. Normative References ..........................................23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 26
A. Change Log (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . . . . . 27
A.1 Since draft-ietf-webdav-redirectref-protocol-02 . . . . . 27
A.2 Since draft-ietf-webdav-redirectref-protocol-03 . . . . . 27
A.3 Since draft-ietf-webdav-redirectref-protocol-04 . . . . . 27
A.4 Since draft-ietf-webdav-redirectref-protocol-05 . . . . . 27
A.5 Since draft-ietf-webdav-redirectref-protocol-06 . . . . . 28
A.6 Since draft-ietf-webdav-redirectref-protocol-07 . . . . . 28
A.7 Since draft-ietf-webdav-redirectref-protocol-08 . . . . . 28
A.8 Since draft-ietf-webdav-redirectref-protocol-09 . . . . . 28
A.9 Since draft-ietf-webdav-redirectref-protocol-10 . . . . . 28
A.10 Since draft-ietf-webdav-redirectref-protocol-11 . . . . 28
A.11 Since draft-ietf-webdav-redirectref-protocol-12 . . . . 28
B. Resolved issues (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . . . . . 29
B.1 8.1_deep_lock_complexity . . . . . . . . . . . . . . . . . 29
B.2 headerreg . . . . . . . . . . . . . . . . . . . . . . . . 29
C. Open issues (to be removed by RFC Editor prior to
publication) . . . . . . . . . . . . . . . . . . . . . . . . 29
C.1 edit . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Intellectual Property and Copyright Statements . . . . . . . 32
1. Introduction 1. Introduction
This specification extends the Web Distributed Authoring Protocol This specification extends the Web Distributed Authoring Protocol
(WebDAV) to enable clients to create new access paths to existing (WebDAV) to enable clients to create new access paths to existing
resources. This capability is useful for several reasons: resources. This capability is useful for several reasons.
WebDAV makes it possible to organize HTTP resources into hierarchies, WebDAV makes it possible to organize HTTP resources into hierarchies,
placing them into groupings, known as collections, which are more placing them into groupings, known as collections, that are more
easily browsed and manipulated than a single flat collection. easily browsed and manipulated than a single flat collection.
However, hierarchies require categorization decisions that locate However, hierarchies require categorization decisions that locate
resources at a single location in the hierarchy, a drawback when a resources at a single location in the hierarchy, a drawback when a
resource has multiple valid categories. For example, in a hierarchy resource has multiple valid categories. For example, in a hierarchy
of vehicle descriptions containing collections for cars and boats, a of vehicle descriptions containing collections for cars and boats, a
description of a combination car/boat vehicle could belong in either description of a combination car/boat vehicle could belong in either
collection. Ideally, the description should be accessible from both. collection. Ideally, the description should be accessible from both.
Allowing clients to create new URIs that access the existing resource Allowing clients to create new URIs that access the existing resource
lets them put that resource into multiple collections. lets them put that resource into multiple collections.
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able to create new access paths to existing resources in other able to create new access paths to existing resources in other
collections or even on other unrelated systems is useful for this collections or even on other unrelated systems is useful for this
sort of case. sort of case.
The redirect reference resources defined here provide a mechanism for The redirect reference resources defined here provide a mechanism for
creating alternative access paths to existing resources. A redirect creating alternative access paths to existing resources. A redirect
reference resource is a resource in one collection whose purpose is reference resource is a resource in one collection whose purpose is
to redirect requests to another resource (its target), possibly in a to redirect requests to another resource (its target), possibly in a
different collection. In this way, it allows clients to submit different collection. In this way, it allows clients to submit
requests to the target resource from another collection. It requests to the target resource from another collection. It
redirects most requests to the target resource using a HTTP status redirects most requests to the target resource using an HTTP status
code from the 3xx range (Redirection), thereby providing a form of code from the 3xx range (Redirection), thereby providing a form of
mediated access to the target resource. mediated access to the target resource.
A redirect reference is a resource with properties but no body of its A redirect reference is a resource with properties but with no body
own. Properties of a redirect reference resource can contain such of its own. Properties of a redirect reference resource can contain
information as who created the reference, when, and why. Since information such as who created the reference, when, and why. Since
redirect reference resources are implemented using HTTP 3xx redirect reference resources are implemented using HTTP 3xx
responses, it generally takes two round trips to submit a request to responses, it generally takes two round trips to submit a request to
the intended resource. Redirect references work equally well for the intended resource. Redirect references work equally well for
local resources and for resources that reside on a different system local resources and for resources that reside on a different system
from the reference. from the reference.
The remainder of this document is structured as follows: Section 3 The remainder of this document is structured as follows: Section 3
defines terms that will be used throughout the specification. defines terms that will be used throughout the specification.
Section 4 provides an overview of redirect reference resources. Section 4 provides an overview of redirect reference resources.
Section 5 defines the semantics of existing methods when applied to Section 5 defines the semantics of existing methods when applied to
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2. Notational Conventions 2. Notational Conventions
Since this document describes a set of extensions to the WebDAV Since this document describes a set of extensions to the WebDAV
Distributed Authoring Protocol [RFC2518], itself an extension to the Distributed Authoring Protocol [RFC2518], itself an extension to the
HTTP/1.1 protocol, the augmented BNF used here to describe protocol HTTP/1.1 protocol, the augmented BNF used here to describe protocol
elements is exactly the same as described in Section 2.1 of elements is exactly the same as described in Section 2.1 of
[RFC2616]. Since this augmented BNF uses the basic production rules [RFC2616]. Since this augmented BNF uses the basic production rules
provided in Section 2.2 of [RFC2616], these rules apply to this provided in Section 2.2 of [RFC2616], these rules apply to this
document as well. document as well.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
document are to be interpreted as described in [RFC2119]. and "OPTIONAL" are to be interpreted as described in [RFC2119].
3. Terminology 3. Terminology
The terminology used here follows and extends that in the WebDAV The terminology used here follows and extends that in the WebDAV
Distributed Authoring Protocol specification [RFC2518]. Definitions Distributed Authoring Protocol specification [RFC2518]. Definitions
of the terms resource, Uniform Resource Identifier (URI), and Uniform of the terms resource, Uniform Resource Identifier (URI), and Uniform
Resource Locator (URL) are provided in [RFC3986]. Resource Locator (URL) are provided in [RFC3986].
Redirect Reference Resource Redirect Reference Resource
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Non-Reference Resource Non-Reference Resource
A resource that is not a reference to another resource. A resource that is not a reference to another resource.
Target Resource Target Resource
The resource to which requests are redirected by a redirect The resource to which requests are redirected by a redirect
reference resource. A target resource can be anything that can be reference resource. A target resource can be anything that can be
identified by an absolute URI (see [RFC3986], "absolute-URI"). identified by an absolute URI (see [RFC3986], "absolute-URI").
This document uses the terms "precondition", "postcondition" and This document uses the terms "precondition", "postcondition", and
"protected property" as defined in [RFC3253]. Servers MUST report "protected property" as defined in [RFC3253]. Servers MUST report
pre-/postcondition failures as described in section 1.6 of this pre-/postcondition failures as described in Section 1.6 of this
document. document.
4. Overview of Redirect Reference Resources 4. Overview of Redirect Reference Resources
For all operations submitted to a redirect reference resource, the For all operations submitted to a redirect reference resource, the
default response is a 302 (Found), accompanied by the Redirect-Ref default response is a 302 (Found), accompanied by the Redirect-Ref
header (defined in Section 12.1 below) and the Location header header (defined in Section 12.1, below) and the Location header
([RFC2616], Section 14.30) set to the URI of the target resource. ([RFC2616], Section 14.30) set to the URI of the target resource.
With this information, the client can resubmit the request to the URI With this information, the client can resubmit the request to the URI
of the target resource. of the target resource.
A redirect reference resource never automatically forwards requests A redirect reference resource never automatically forwards requests
to its target resource. Redirect resources bring the same benefits to its target resource. Redirect resources bring the same benefits
as links in HTML documents. They can be created and maintained as links in HTML documents. They can be created and maintained
without the involvement or even knowledge of their target resource. without the involvement or even knowledge of their target resource.
This reduces the cost of linking between resources. This reduces the cost of linking between resources.
If the client is aware that it is operating on a redirect reference If the client is aware that it is operating on a redirect reference
resource, it can resolve the reference by retrieving the reference resource, it can resolve the reference by retrieving the reference
resource's DAV:reftarget property (defined in Section 13.2 below), resource's DAV:reftarget property (defined in Section 13.2, below),
whose value contains the URI of the target resource. It can then whose value contains the URI of the target resource. It can then
submit requests to the target resource. submit requests to the target resource.
A redirect reference resource is a new type of resource. To A redirect reference resource is a new type of resource. To
distinguish redirect reference resources from non-reference distinguish redirect reference resources from non-reference
resources, a new value of the DAV:resourcetype property (defined in resources, a new value of the DAV:resourcetype property (defined in
[RFC2518]), DAV:redirectref, is defined in Section 14.1 below. [RFC2518]), DAV:redirectref, is defined in Section 14.1, below.
Since a redirect reference resource is a resource, methods can be Since a redirect reference resource is a resource, methods can be
applied to the reference resource as well as to its target resource. applied to the reference resource as well as to its target resource.
The Apply-To-Redirect-Ref request header (defined in Section 12.2
The Apply-To-Redirect-Ref request header (defined in Section 12.2,
below) is provided so that referencing-aware clients can control below) is provided so that referencing-aware clients can control
whether an operation is applied to the redirect reference resource or whether an operation is applied to the redirect reference resource or
standard HTTP/WebDAV behaviour (redirection with a 3xx status code) standard HTTP/WebDAV behaviour (redirection with a 3xx status code)
should occur. The Apply-To-Redirect-Ref header can be used with most should occur. The Apply-To-Redirect-Ref header can be used with most
requests to redirect reference resources. This header is requests to redirect reference resources. This header is
particularly useful with PROPFIND, to retrieve the reference particularly useful with PROPFIND, to retrieve the reference
resource's own properties. resource's own properties.
Implementation Note: Operations on the target of a redirect reference Implementation Note: Operations on the target of a redirect reference
usually do not affect the redirect reference itself. However, usually do not affect the redirect reference itself. However,
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5. Operations on Redirect Reference Resources 5. Operations on Redirect Reference Resources
Although non-referencing-aware clients cannot create reference Although non-referencing-aware clients cannot create reference
resources, they should be able to submit requests through the resources, they should be able to submit requests through the
reference resources created by reference-aware WebDAV clients. They reference resources created by reference-aware WebDAV clients. They
should be able to follow any references to their targets. To make should be able to follow any references to their targets. To make
this possible, a server that receives any request made via a redirect this possible, a server that receives any request made via a redirect
reference resource MUST return a 3xx range (Redirection) status code, reference resource MUST return a 3xx range (Redirection) status code,
unless the request includes an Apply-To-Redirect-Ref header unless the request includes an Apply-To-Redirect-Ref header
specifying "T". The client and server MUST follow [RFC2616] Section specifying "T". The client and server MUST follow [RFC2616], Section
10.3, but with these additional rules: 10.3, but with these additional rules:
o The Location response header MUST contain an URI (see [RFC3986], o The Location response header MUST contain a URI (see [RFC3986],
Section 3) that identifies the target of the reference resource. Section 3) that identifies the target of the reference resource.
o The response MUST include the Redirect-Ref header. This header o The response MUST include the Redirect-Ref header. This header
allows reference-aware WebDAV clients to recognize the resource as allows reference-aware WebDAV clients to recognize the resource as
a reference resource and understand the reason for the a reference resource and to understand the reason for the
redirection. redirection.
A reference-aware WebDAV client can, like a non-referencing client, A reference-aware WebDAV client can, like a non-referencing client,
resubmit the request to the URI in the Location header in order to resubmit the request to the URI in the Location header in order to
operate on the target resource. Alternatively, it can resubmit the operate on the target resource. Alternatively, it can resubmit the
request to the URI of the redirect reference resource with the request to the URI of the redirect reference resource with the
"Apply-To-Redirect-Ref: T" header in order to operate on the "Apply-To-Redirect-Ref: T" header in order to operate on the
reference resource itself. In this case, the request MUST be applied reference resource itself. In this case, the request MUST be applied
to the reference resource itself, and a 3xx response MUST NOT be to the reference resource itself, and a 3xx response MUST NOT be
returned. returned.
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6. MKREDIRECTREF Method 6. MKREDIRECTREF Method
The MKREDIRECTREF method requests the creation of a redirect The MKREDIRECTREF method requests the creation of a redirect
reference resource. reference resource.
If a MKREDIRECTREF request fails, the server state preceding the If a MKREDIRECTREF request fails, the server state preceding the
request MUST be restored. request MUST be restored.
Responses from a MKREDIRECTREF request MUST NOT be cached, as Responses from a MKREDIRECTREF request MUST NOT be cached, as
MKREDIRECTREF has non-idempotent and non-safe semantics (see MKREDIRECTREF has non-idempotent and non-safe semantics (see
[RFC2616], Section 9.1).
[RFC2616], section 9.1). Marshalling
Marshalling:
The request body MUST be a DAV:mkredirectref XML element. The request body MUST be a DAV:mkredirectref XML element.
<!ELEMENT mkredirectref (reftarget, redirect-lifetime?)> <!ELEMENT mkredirectref (reftarget, redirect-lifetime?)>
<!ELEMENT reftarget (href)> <!ELEMENT reftarget (href)>
<!ELEMENT redirect-lifetime (permanent | temporary)> <!ELEMENT redirect-lifetime (permanent | temporary)>
<!ELEMENT permanent EMPTY> <!ELEMENT permanent EMPTY>
<!ELEMENT temporary EMPTY> <!ELEMENT temporary EMPTY>
The DAV:href element is defined in [RFC2518] (Section 12.3) and The DAV:href element is defined in [RFC2518] (Section 12.3) and
MUST contain either an URI or a relative-ref (see [RFC3986], MUST contain either a URI or a relative-ref (see [RFC3986],
Sections 3 and 4.2). Sections 3 and 4.2).
If no DAV:redirect-lifetime element is specified, the server MUST If no DAV:redirect-lifetime element is specified, the server MUST
behave as if a value of DAV:temporary was specified. behave as if a value of DAV:temporary was specified.
If the request succeeds, the server MUST return 201 (Created) If the request succeeds, the server MUST return 201 (Created)
status. status.
If a response body for a successful request is included, it MUST If a response body for a successful request is included, it MUST
be a DAV:mkredirectref-response XML element. Note that this be a DAV:mkredirectref-response XML element. Note that this
document does not define any elements for the MKREDIRECTREF document does not define any elements for the MKREDIRECTREF
response body, but the DAV:mkredirectref-response element is response body, but the DAV:mkredirectref-response element is
defined to ensure interoperability between future extensions that defined to ensure interoperability between future extensions that
do define elements for the response body. do define elements for the response body.
<!ELEMENT mkredirectref-response ANY> <!ELEMENT mkredirectref-response ANY>
Preconditions: Preconditions
(DAV:resource-must-be-null): A resource MUST NOT exist at the (DAV:resource-must-be-null): A resource MUST NOT exist at the
Request-URI. Request-URI.
(DAV:parent-resource-must-be-non-null): The Request-URI minus the (DAV:parent-resource-must-be-non-null): The Request-URI minus the
last past segment MUST identify a collection. last past segment MUST identify a collection.
(DAV:name-allowed): The last segment of the Request-URI is (DAV:name-allowed): The last segment of the Request-URI is
available for use as a resource name. available for use as a resource name.
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appropriate token MUST be specified in an If request header. appropriate token MUST be specified in an If request header.
(DAV:redirect-lifetime-supported): If the request body contains a (DAV:redirect-lifetime-supported): If the request body contains a
DAV:redirect-lifetime element, the server MUST support the DAV:redirect-lifetime element, the server MUST support the
specified lifetime. Support for DAV:temporary is REQUIRED, while specified lifetime. Support for DAV:temporary is REQUIRED, while
support for DAV:permanent is OPTIONAL. support for DAV:permanent is OPTIONAL.
(DAV:legal-reftarget): The specified is a legal URI or relative- (DAV:legal-reftarget): The specified is a legal URI or relative-
ref. ref.
Postconditions: Postconditions
(DAV:new-redirectref): a new redirect reference resource is (DAV:new-redirectref): a new redirect reference resource is
created whose DAV:reftarget property has the value specified in created whose DAV:reftarget property has the value specified in
the request body. the request body.
6.1 Example: Creating a Redirect Reference Resource with MKREDIRECTREF 6.1. Example: Creating a Redirect Reference Resource with MKREDIRECTREF
>> Request: >> Request:
MKREDIRECTREF /~whitehead/dav/spec08.ref HTTP/1.1 MKREDIRECTREF /~whitehead/dav/spec08.ref HTTP/1.1
Host: www.example.com Host: www.example.com
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:mkredirectref xmlns:D="DAV:"> <D:mkredirectref xmlns:D="DAV:">
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<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:mkredirectref xmlns:D="DAV:"> <D:mkredirectref xmlns:D="DAV:">
<D:reftarget> <D:reftarget>
<D:href>/i-d/draft-webdav-protocol-08.txt</D:href> <D:href>/i-d/draft-webdav-protocol-08.txt</D:href>
</D:reftarget> </D:reftarget>
</D:mkredirectref> </D:mkredirectref>
>> Response: >> Response:
HTTP/1.1 201 Created HTTP/1.1 201 Created
This request resulted in the creation of a new redirect reference This request resulted in the creation of a new redirect reference
resource at http://www.example.com/~whitehead/dav/spec08.ref, which resource at http://www.example.com/~whitehead/dav/spec08.ref, which
points to the resource identified by the DAV:reftarget property. In points to the resource identified by the DAV:reftarget property. In
this example, the target resource is identified by the URI this example, the target resource is identified by the URI
http://www.example.com/i-d/draft-webdav-protocol-08.txt. The http://www.example.com/i-d/draft-webdav-protocol-08.txt. The
redirect reference resource's DAV:resourcetype property is set to redirect reference resource's DAV:resourcetype property is set to
DAV:redirectref and it's DAV:redirect-lifetime property has the value DAV:redirectref, and its DAV:redirect-lifetime property has the value
DAV:temporary. DAV:temporary.
7. UPDATEREDIRECTREF Method 7. UPDATEREDIRECTREF Method
The UPDATEREDIRECTREF method requests the update of a redirect The UPDATEREDIRECTREF method requests the update of a redirect
reference resource. reference resource.
If a UPDATEREDIRECTREF request fails, the server state preceding the If a UPDATEREDIRECTREF request fails, the server state preceding the
request MUST be restored. request MUST be restored.
Responses from a UPDATEREDIRECTREF request MUST NOT be cached, as Responses from a UPDATEREDIRECTREF request MUST NOT be cached, as
UPDATEREDIRECTREF has non-safe semantics (see [RFC2616], section UPDATEREDIRECTREF has non-safe semantics (see [RFC2616], Section
9.1). 9.1).
Marshalling: Marshalling
The request body MUST be a DAV:updateredirectref XML element. The request body MUST be a DAV:updateredirectref XML element.
<!ELEMENT updateredirectref (reftarget?, redirect-lifetime?)> <!ELEMENT updateredirectref (reftarget?, redirect-lifetime?)>
See Section 6 for a definition of DAV:reftarget and DAV:redirect- See Section 6 for a definition of DAV:reftarget and DAV:redirect-
lifetime. lifetime.
If no DAV:reftarget element is specified, the server MUST NOT If no DAV:reftarget element is specified, the server MUST NOT
change the target of the redirect reference. change the target of the redirect reference.
If no DAV:redirect-lifetime element is specified, the server MUST If no DAV:redirect-lifetime element is specified, the server MUST
NOT change the lifetime of the redirect reference. NOT change the lifetime of the redirect reference.
If a response body for a successful request is included, it MUST If a response body for a successful request is included, it MUST
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If a response body for a successful request is included, it MUST If a response body for a successful request is included, it MUST
be a DAV:updateredirectref-response XML element. Note that this be a DAV:updateredirectref-response XML element. Note that this
document does not define any elements for the UPDATEREDIRECTREF document does not define any elements for the UPDATEREDIRECTREF
response body, but the DAV:updateredirectref-response element is response body, but the DAV:updateredirectref-response element is
defined to ensure interoperability between future extensions that defined to ensure interoperability between future extensions that
do define elements for the response body. do define elements for the response body.
<!ELEMENT updateredirectref-response ANY> <!ELEMENT updateredirectref-response ANY>
Preconditions: Preconditions
(DAV:locked-update-allowed): if the resource is write-locked, then (DAV:locked-update-allowed): if the resource is write-locked, then
the appropriate token MUST be specified in an If request header. the appropriate token MUST be specified in an If request header.
(DAV:must-be-redirectref): the resource identified by the Request- (DAV:must-be-redirectref): the resource identified by the
URI must be a redirect reference resource as defined by this Request-URI must be a redirect reference resource as defined by
specification. this specification.
(DAV:redirect-lifetime-supported): see Section 6. (DAV:redirect-lifetime-supported): see Section 6.
(DAV:redirect-lifetime-update-supported): servers MAY support (DAV:redirect-lifetime-update-supported): servers MAY support
changing the DAV:redirect-lifetime property; if they don't, this changing the DAV:redirect-lifetime property; if they don't, this
condition code can be used to signal failure. condition code can be used to signal failure.
(DAV:legal-reftarget): see Section 6. (DAV:legal-reftarget): see Section 6.
Postconditions: Postconditions
(DAV:redirectref-updated): the DAV:reftarget and DAV:redirect- (DAV:redirectref-updated): the DAV:reftarget and DAV:redirect-
lifetime properties of the redirect reference have been updated lifetime properties of the redirect reference have been updated
accordingly. accordingly.
7.1 Example: Updating a Redirect Reference Resource with 7.1. Example: Updating a Redirect Reference Resource with
UPDATEREDIRECTREF UPDATEREDIRECTREF
>> Request: >> Request:
UPDATEREDIRECTREF /~whitehead/dav/spec08.ref HTTP/1.1 UPDATEREDIRECTREF /~whitehead/dav/spec08.ref HTTP/1.1
Host: www.example.com Host: www.example.com
Apply-To-Redirect-Ref: T Apply-To-Redirect-Ref: T
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
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<D:reftarget> <D:reftarget>
<D:href>/i-d/draft-webdav-protocol-08b.txt</D:href> <D:href>/i-d/draft-webdav-protocol-08b.txt</D:href>
</D:reftarget> </D:reftarget>
</D:updateredirectref> </D:updateredirectref>
>> Response: >> Response:
HTTP/1.1 200 OK HTTP/1.1 200 OK
This request has updated the redirect reference's DAV:reftarget This request has updated the redirect reference's DAV:reftarget
property to "/i-d/draft-webdav-protocol-08b.txt", and has not changed property to "/i-d/draft-webdav-protocol-08b.txt" and has not changed
the DAV:redirect-lifetime value. Note that the "Apply-To-Redirect- the DAV:redirect-lifetime value. Note that the "Apply-To-Redirect-
Ref" request header must be used, otherwise the request would result Ref" request header must be used; otherwise, the request would result
in a redirect (3xx) response status. in a redirect (3xx) response status.
8. Operations on Collections That Contain Redirect Reference Resources 8. Operations on Collections That Contain Redirect Reference Resources
According to [RFC2518], Section 9.2, methods that have defined According to [RFC2518], Section 9.2, methods that have defined
interactions with the "Depth" request header should apply all other interactions with the "Depth" request header should apply all other
request headers to each resource in scope. However, applying this request headers to each resource in scope. However, applying this
principle to the "Apply-To-Redirect-Ref" header uniformly would make principle to the "Apply-To-Redirect-Ref" header uniformly would make
it impractical to implement this specification on top of existing it impractical to implement this specification on top of existing
servers and also would result in unexpected server behaviour for servers and also would result in unexpected server behaviour for
clients that do not take the existence of redirect references into clients that do not take the existence of redirect references into
account. On the other hand, the definition of the "Depth" header account. On the other hand, the definition of the "Depth" header
allows to explicitly define alternate behaviours. allows alternate behaviours to be explicitly defined.
For this reason, this specification defines the interaction between For this reason, this specification defines the interaction between
"Depth" and "Apply-To-Redirect-Ref" request headers on a case-by-case "Depth" and "Apply-To-Redirect-Ref" request headers on a case-by-case
basis, and also provides a default for methods not mentioned here basis and also provides a default for methods not mentioned here that
that do not specify the behaviour themselves. do not specify the behaviour themselves.
+-------------+-----------------+------------------+-----------+ +-------------+-----------------+------------------+-----------+
| method name | defined in | supported depths | behaviour | | method name | defined in | supported depths | behaviour |
+-------------+-----------------+------------------+-----------+ +-------------+-----------------+------------------+-----------+
| COPY | [RFC2518], 8.9 | 0, infinity | "T" | | COPY | [RFC2518], 8.9 | 0, infinity | "T" |
| DELETE | [RFC2518], 8.7 | infinity | "T" | | DELETE | [RFC2518], 8.7 | infinity | "T" |
| LOCK | [RFC2518], 8.11 | 0, infinity | "T" | | LOCK | [RFC2518], 8.11 | 0, infinity | "T" |
| MOVE | [RFC2518], 8.10 | 0, infinity | "T" | | MOVE | [RFC2518], 8.10 | 0, infinity | "T" |
| PROPFIND | [RFC2518], 8.2 | 0, 1, infinity | inherit | | PROPFIND | [RFC2518], 8.2 | 0, 1, infinity | inherit |
| REPORT | [RFC3253], 3.6 | 0, 1, infinity | inherit | | REPORT | [RFC3253], 3.6 | 0, 1, infinity | inherit |
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When the behaviour is defined to be "inherit", the method should When the behaviour is defined to be "inherit", the method should
follow RFC2518's default behaviour for "Depth" operations, which follow RFC2518's default behaviour for "Depth" operations, which
means applying the value given for "Apply-To-Redirect-Ref" to each means applying the value given for "Apply-To-Redirect-Ref" to each
resource in scope. On the other hand, when it is defined to be "T", resource in scope. On the other hand, when it is defined to be "T",
the method should behave as if a "Apply-To-Redirect-Ref: T" header the method should behave as if a "Apply-To-Redirect-Ref: T" header
was specified for each operation on child resources. The latter was specified for each operation on child resources. The latter
ensures that "Depth: infinity" operations will not fail unexpectedly ensures that "Depth: infinity" operations will not fail unexpectedly
just because there was a redirect reference resource in scope. just because there was a redirect reference resource in scope.
8.1 Example: PROPFIND on a Collection with Redirect Reference Resources 8.1. Example: PROPFIND on a Collection with Redirect Reference
Resources
Suppose a PROPFIND request with Depth: infinity is submitted to the Suppose a PROPFIND request with Depth: infinity is submitted to the
following collection, with the members shown here: following collection, with the members shown here:
/MyCollection/ /MyCollection/
(non-reference resource) diary.html (non-reference resource) diary.html
(redirect reference resource) nunavut (redirect reference resource) nunavut
>> Request: >> Request:
skipping to change at page 15, line 41 skipping to change at page 13, line 15
</D:response> </D:response>
<D:response> <D:response>
<D:href>/MyCollection/nunavut</D:href> <D:href>/MyCollection/nunavut</D:href>
<D:status>HTTP/1.1 302 Found</D:status> <D:status>HTTP/1.1 302 Found</D:status>
<D:location> <D:location>
<D:href>http://example.ca/art/inuit/</D:href> <D:href>http://example.ca/art/inuit/</D:href>
</D:location> </D:location>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
In this example the Depth header is set to infinity, and the Apply- In this example, the Depth header is set to infinity, and the Apply-
To-Redirect-Ref header is set to "F". The collection contains one To-Redirect-Ref header is set to "F". The collection contains one
URI that identifies a redirect reference resource. The response URI that identifies a redirect reference resource. The response
element for the redirect reference resource has a status of 302 element for the redirect reference resource has a status of 302
(Found), and includes a DAV:location extension element to allow (Found) and includes a DAV:location extension element to allow
clients to retrieve the properties of its target resource. (The clients to retrieve the properties of its target resource. (The
response element for the redirect reference resource does not include response element for the redirect reference resource does not include
the requested properties. The client can submit another PROPFIND the requested properties. The client can submit another PROPFIND
request to the URI in the DAV:location pseudo-property to retrieve request to the URI in the DAV:location pseudo-property to retrieve
those properties.) those properties.)
8.2 Example: PROPFIND with Apply-To-Redirect-Ref on a Collection with 8.2. Example: PROPFIND with Apply-To-Redirect-Ref on a Collection with
Redirect Reference Resources Redirect Reference Resources
Suppose a PROPFIND request with "Apply-To-Redirect-Ref: T" and Depth: Suppose a PROPFIND request with "Apply-To-Redirect-Ref: T" and Depth:
infinity is submitted to the following collection, with the members infinity is submitted to the following collection, with the members
shown here: shown here:
/MyCollection/ /MyCollection/
(non-reference resource) diary.html (non-reference resource) diary.html
(redirect reference resource) nunavut (redirect reference resource) nunavut
>> Request: >> Request:
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Since the "Apply-To-Redirect-Ref: T" header is present, the response Since the "Apply-To-Redirect-Ref: T" header is present, the response
shows the properties of the redirect reference resource in the shows the properties of the redirect reference resource in the
collection rather than reporting a 302 status. collection rather than reporting a 302 status.
9. Operations on Targets of Redirect Reference Resources 9. Operations on Targets of Redirect Reference Resources
Operations on targets of redirect reference resources have no effect Operations on targets of redirect reference resources have no effect
on the reference resource. on the reference resource.
10. Relative references in DAV:reftarget 10. Relative References in DAV:reftarget
The URI in the href in a DAV:reftarget property MAY be a relative The URI in the href in a DAV:reftarget property MAY be a relative
reference. In this case, the base URI to be used for resolving it to reference. In this case, the base URI to be used for resolving it to
absolute form is the URI used in the HTTP message to identify the absolute form is the URI used in the HTTP message to identify the
redirect reference resource to which the DAV:reftarget property redirect reference resource to which the DAV:reftarget property
belongs. belongs.
When DAV:reftarget appears in the context of a Multi-Status response, 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 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 element. The value of this DAV:href element serves as the base URI
for resolving a relative reference in DAV:reftarget. The value of for resolving a relative reference in DAV:reftarget. The value of
DAV:href may itself be relative, in which case it must be resolved 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 reference in first in order to serve as the base URI for the relative reference in
DAV:reftarget. If the DAV:href element is relative, its base URI is DAV:reftarget. If the DAV:href element is relative, its base URI is
constructed from the scheme component "http", the value of the Host constructed from the scheme component "http", the value of the Host
header in the request, and the Request-URI. header in the request, and the Request-URI.
10.1 Example: Resolving a Relative Reference in a Multi-Status Response 10.1. Example: Resolving a Relative Reference in a Multi-Status
Response
>> Request: >> Request:
PROPFIND /geog/ HTTP/1.1 PROPFIND /geog/ HTTP/1.1
Host: example.com Host: example.com
Apply-To-Redirect-Ref: T Apply-To-Redirect-Ref: T
Depth: 1 Depth: 1
Content-Type: text/xml Content-Type: text/xml
Content-Length: nnn Content-Length: nnn
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<D:status>HTTP/1.1 404 Not Found</D:status> <D:status>HTTP/1.1 404 Not Found</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
<D:response> <D:response>
<D:href>/geog/stats.html</D:href> <D:href>/geog/stats.html</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<D:resourcetype><D:redirectref/></D:resourcetype> <D:resourcetype><D:redirectref/></D:resourcetype>
<D:reftarget> <D:reftarget>
<D:href>statistics/population/1997.html</D:href> <D:href>statistics/population/1997.html</D:href>
</D:reftarget> </D:reftarget>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
In this example, the relative reference "statistics/population/ In this example, the relative reference
1997.html" is returned as the value of the DAV:reftarget property for "statistics/population/1997.html" is returned as the value of the
the reference resource identified by href /geog/stats.html. The href DAV:reftarget property for the reference resource identified by href
is itself a relative reference, which resolves to /geog/stats.html. The href is itself a relative reference, which
http://example.com/geog/stats.html. This is the base URI for resolves to http://example.com/geog/stats.html. This is the base URI
resolving the relative reference in reftarget. The absolute URI of for resolving the relative reference in reftarget. The absolute URI
reftarget is http://example.com/geog/statistics/population/1997.html. of reftarget is
http://example.com/geog/statistics/population/1997.html.
11. Redirect References to Collections 11. Redirect References to Collections
In a Request-URI /segment1/segment2/segment3, any of the three In a Request-URI /segment1/segment2/segment3, any of the three
segments may identify a redirect reference resource. (See [RFC3986], segments may identify a redirect reference resource. (See [RFC3986],
Section 3.3, for definitions of "path" and "segment".) If any Section 3.3, for definitions of "path" and "segment".) If any
segment in a Request-URI identifies a redirect reference resource, segment in a Request-URI identifies a redirect reference resource,
the response SHOULD be a 3xx. The value of the Location header in the response SHOULD be a 3xx. The value of the Location header in
the response is as follows: the response is as follows:
The leftmost path segment of the Request-URI that identifies a The leftmost path segment of the Request-URI that identifies a
redirect reference resource, together with all path segments and redirect reference resource, together with all path segments and
separators to the left of it, is replaced by the value of the separators to the left of it, is replaced by the value of the
redirect reference resource's DAV:reftarget property (resolved to an redirect reference resource's DAV:reftarget property (resolved to an
absolute URI). The remainder of the Request-URI is concatenated to absolute URI). The remainder of the Request-URI is concatenated to
this path. this path.
Note: If the DAV:reftarget property ends with a "/" and the remainder 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 of the Request-URI is non-empty (and therefore must begin with a
"/"), the final "/" in the DAV:reftarget property is dropped before "/"), the final "/" in the DAV:reftarget property is dropped before
the remainder of the Request-URI is appended. the remainder of the Request-URI is appended.
Consider Request-URI /x/y/z.html. Suppose that /x/ is a redirect Consider Request-URI /x/y/z.html. Suppose that /x/ is a redirect
reference resource whose target resource is collection /a/, which reference resource, whose target resource is collection /a/, which
contains redirect reference resource y whose target resource is contains redirect reference resource y whose target resource is
collection /b/, which contains redirect reference resource z.html collection /b/, which contains redirect reference resource z.html,
whose target resource is /c/d.html. whose target resource is /c/d.html.
/x/y/z.html /x/y/z.html
| |
| /x -> /a | /x -> /a
| |
v v
/a/y/z.html /a/y/z.html
| |
| /a/y -> /b | /a/y -> /b
| |
v v
/b/z.html /b/z.html
| |
| /b/z.html -> /c/d.html | /b/z.html -> /c/d.html
| |
v v
/c/d.html /c/d.html
In this case the client must follow up three separate 3xx responses In this case, the client must follow up three separate 3xx responses
before finally reaching the target resource. The server responds to before finally reaching the target resource. The server responds to
the initial request with a 3xx with Location: /a/y/z.html, and the the initial request with a 3xx with Location: /a/y/z.html, and the
client resubmits the request to /a/y/z.html. The server responds to client resubmits the request to /a/y/z.html. The server responds to
this request with a 3xx with Location: /b/z.html, and the client this request with a 3xx with Location: /b/z.html, and the client
resubmits the request to /b/z.html. The server responds to this resubmits the request to /b/z.html. The server responds to this
request with a 3xx with Location: /c/d.html, and the client resubmits request with a 3xx with Location: /c/d.html, and the client resubmits
the request to /c/d.html. This final request succeeds. the request to /c/d.html. This final request succeeds.
Note: the behavior described above may have a very serious impact Note: The behaviour described above may have a very serious impact
on the efficiency of mapping Request-URIs to resources in HTTP on the efficiency of mapping Request-URIs to resources in HTTP
request processing. Therefore servers MAY respond with a 404 request processing. Therefore, servers MAY respond with a 404
status code if the cost of checking all leading path segments for status code if the cost of checking all leading path segments for
redirect references seems prohibitive. redirect references seems prohibitive.
12. Headers 12. Headers
12.1 Redirect-Ref Response Header 12.1. Redirect-Ref Response Header
Redirect-Ref = "Redirect-Ref:" (URI | relative-ref) Redirect-Ref = "Redirect-Ref:" (URI | relative-ref)
; URI: see [RFC3986], Section 3 ; URI: see [RFC3986], Section 3
; relative-ref: see [RFC3986], Section 4.2 ; relative-ref: see [RFC3986], Section 4.2
The Redirect-Ref header is used in all 3xx responses from redirect The Redirect-Ref header is used in all 3xx responses from redirect
reference resources. The value is the link target as specified reference resources. The value is the link target as specified
during redirect reference resource creation. during redirect reference resource creation.
12.2 Apply-To-Redirect-Ref Request Header 12.2. Apply-To-Redirect-Ref Request Header
Apply-To-Redirect-Ref = "Apply-To-Redirect-Ref" ":" ("T" | "F") Apply-To-Redirect-Ref = "Apply-To-Redirect-Ref" ":" ("T" | "F")
The optional Apply-To-Redirect-Ref header can be used on any request The optional Apply-To-Redirect-Ref header can be used on any request
to a redirect reference resource. When it is present and set to "T", to a redirect reference resource. When it is present and set to "T",
the request MUST be applied to the reference resource itself, and a the request MUST be applied to the reference resource itself, and a
3xx response MUST NOT be returned. 3xx response MUST NOT be returned.
If the Apply-To-Redirect-Ref header is used on a request to any other 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 sort of resource besides a redirect reference resource, the server
MUST ignore it. MUST ignore it.
13. Redirect Reference Resource Properties 13. Redirect Reference Resource Properties
The properties defined below are REQUIRED on redirect reference The properties defined below are REQUIRED on redirect reference
resources. A PROPFIND/allprop request SHOULD NOT return any of the resources. A PROPFIND/allprop request SHOULD NOT return any of the
properties defined in this document. properties defined in this document.
13.1 DAV:redirect-lifetime (protected) 13.1. DAV:redirect-lifetime (protected)
This property provides information about the lifetime of a redirect. This property provides information about the lifetime of a redirect.
It can either be DAV:permanent (HTTP status 301) or DAV:temporary It can be either DAV:permanent (HTTP status 301) or DAV:temporary
(HTTP status 302). Future protocols may define additional values. (HTTP status 302). Future protocols may define additional values.
<!ELEMENT redirect-lifetime (permanent | temporary)> <!ELEMENT redirect-lifetime (permanent | temporary)>
<!ELEMENT permanent EMPTY> <!ELEMENT permanent EMPTY>
<!ELEMENT temporary EMPTY> <!ELEMENT temporary EMPTY>
13.2 DAV:reftarget (protected) 13.2. DAV:reftarget (protected)
This property provides an efficient way for clients to discover the This property provides an efficient way for clients to discover the
URI of the target resource. This is a read-only property after its URI of the target resource. This is a read-only property after its
initial creation. Its value can only be set in a MKREDIRECTREF initial creation. Its value can only be set in a MKREDIRECTREF
request. The value is a DAV:href element containing the URI of the request. The value is a DAV:href element containing the URI of the
target resource. target resource.
<!ELEMENT reftarget href > <!ELEMENT reftarget href >
14. XML Elements 14. XML Elements
14.1 redirectref XML Element 14.1. redirectref XML Element
Name: redirectref Name: redirectref
Namespace: DAV: Namespace: DAV:
Purpose: Used as the value of the DAV:resourcetype property to Purpose: Used as the value of the DAV:resourcetype property to
specify that the resource type is a redirect reference resource. specify that the resource type is a redirect reference resource.
<!ELEMENT redirectref EMPTY > <!ELEMENT redirectref EMPTY >
15. Extensions to the DAV:response XML Element for Multi-Status 15. Extensions to the DAV:response XML Element for Multi-Status
Responses Responses
As described in Section 8, the DAV:location element may be returned As described in Section 8, the DAV:location element may be returned
in the DAV:response element of a 207 Multi-Status response, to allow in the DAV:response element of a 207 Multi-Status response, to allow
clients to resubmit their requests to the target resource of a clients to resubmit their requests to the target resource of a
redirect reference resource. redirect reference resource.
Consequently, the definition of the DAV:response XML element changes Consequently, the definition of the DAV:response XML element changes
to the following: to the following:
<!ELEMENT response (href, ((href*, status)|(propstat+)), <!ELEMENT response (href, ((href*, status)|(propstat+)),
responsedescription?, location?) > responsedescription?, location?) >
<!ELEMENT location (href) > <!ELEMENT location (href) >
16. Capability Discovery 16. Capability Discovery
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requests. If a resource does support redirect references, its requests. If a resource does support redirect references, its
response to an OPTIONS request may indicate that it does, by listing response to an OPTIONS request may indicate that it does, by listing
the new redirectrefs compliance class in the DAV header and by the new redirectrefs compliance class in the DAV header and by
listing the MKREDIRECTREF method as one it supports. listing the MKREDIRECTREF method as one it supports.
When responding to an OPTIONS request, any type of resource can When responding to an OPTIONS request, any type of resource can
include redirectrefs in the value of the DAV header. Doing so include redirectrefs in the value of the DAV header. Doing so
indicates that the server permits a redirect reference resource at indicates that the server permits a redirect reference resource at
the Request-URI. the Request-URI.
16.1 Example: Discovery of Support for Redirect Reference Resources 16.1. Example: Discovery of Support for Redirect Reference Resources
>> Request: >> Request:
OPTIONS /somecollection/someresource HTTP/1.1 OPTIONS /somecollection/someresource HTTP/1.1
Host: example.org Host: example.org
>> Response: >> Response:
HTTP/1.1 200 OK HTTP/1.1 200 OK
Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE
Allow: MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, MKREDIRECTREF Allow: MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, MKREDIRECTREF
DAV: 1, 2, redirectrefs DAV: 1, 2, redirectrefs
The DAV header in the response indicates that the resource The DAV header in the response indicates that the resource
/somecollection/someresource is level 1 and level 2 compliant, as /somecollection/someresource is level 1 and level 2 compliant, as
defined in [RFC2518]. In addition, /somecollection/someresource defined in [RFC2518]. In addition, /somecollection/someresource
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HTTP/1.1 200 OK HTTP/1.1 200 OK
Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE
Allow: MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, MKREDIRECTREF Allow: MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, MKREDIRECTREF
DAV: 1, 2, redirectrefs DAV: 1, 2, redirectrefs
The DAV header in the response indicates that the resource The DAV header in the response indicates that the resource
/somecollection/someresource is level 1 and level 2 compliant, as /somecollection/someresource is level 1 and level 2 compliant, as
defined in [RFC2518]. In addition, /somecollection/someresource defined in [RFC2518]. In addition, /somecollection/someresource
supports redirect reference resources. The Allow header indicates supports redirect reference resources. The Allow header indicates
that MKREDIRECTREF requests can be submitted to /somecollection/ that MKREDIRECTREF requests can be submitted to
someresource. /somecollection/someresource.
17. Security Considerations 17. Security Considerations
This section is provided to make applications that implement this This section is provided to make applications that implement this
protocol aware of the security implications of this protocol. protocol aware of the security implications of this protocol.
All of the security considerations of HTTP/1.1 and the WebDAV All of the security considerations of HTTP/1.1 and the WebDAV
Distributed Authoring Protocol specification also apply to this Distributed Authoring Protocol specification also apply to this
protocol specification. In addition, redirect reference resources protocol specification. In addition, redirect reference resources
introduce several new security concerns and increase the risk of some introduce several new security concerns and increase the risk of some
existing threats. These issues are detailed below. existing threats. These issues are detailed below.
17.1 Privacy Concerns 17.1. Privacy Concerns
By creating redirect reference resources on a trusted server, it is By creating redirect reference resources on a trusted server, it is
possible for a hostile agent to induce users to send private possible for a hostile agent to induce users to send private
information to a target on an unrelated system. This risk is information to a target on an unrelated system. This risk is
mitigated somewhat, since clients are required to notify the user of mitigated somewhat, since clients are required to notify the user of
the redirection for any request other than GET or HEAD. (See the redirection for any request other than GET or HEAD. (See
[RFC2616], Section 10.3.3 302 Found.) [RFC2616], Section 10.3.3, 302 Found.)
17.2 Redirect Loops 17.2. Redirect Loops
Although redirect loops were already possible in HTTP 1.1, the Although redirect loops were already possible in HTTP 1.1, the
introduction of the MKREDIRECTREF method creates a new avenue for introduction of the MKREDIRECTREF method creates a new avenue for
clients to create loops accidentally or maliciously. If the clients to create loops accidentally or maliciously. If the
reference resource and its target are on the same server, the server reference resource and its target are on the same server, the server
may be able to detect MKREDIRECTREF requests that would create loops. may be able to detect MKREDIRECTREF requests that would create loops.
See also [RFC2616], Section 10.3 "Redirection 3xx." See also [RFC2616], Section 10.3, "Redirection 3xx."
17.3 Redirect Reference Resources and Denial of Service 17.3. Redirect Reference Resources and Denial of Service
Denial of service attacks were already possible by posting URLs that Denial of service attacks were already possible by posting URLs that
were intended for limited use at heavily used Web sites. The were intended for limited use at heavily used Web sites. The
introduction of MKREDIRECTREF creates a new avenue for similar denial introduction of MKREDIRECTREF creates a new avenue for similar denial
of service attacks. Clients can now create redirect reference of service attacks. Clients can now create redirect reference
resources at heavily used sites to target locations that were not resources at heavily used sites to target locations that were not
designed for heavy usage. designed for heavy usage.
17.4 Revealing Private Locations 17.4. Revealing Private Locations
There are several ways that redirect reference resources may reveal There are several ways that redirect reference resources may reveal
information about collection structures. First, the DAV:reftarget information about collection structures. First, the DAV:reftarget
property of every redirect reference resource contains the URI of the property of every redirect reference resource contains the URI of the
target resource. Anyone who has access to the reference resource can target resource. Anyone who has access to the reference resource can
discover the collection path that leads to the target resource. The discover the collection path that leads to the target resource. The
owner of the target resource may have wanted to limit knowledge of owner of the target resource may have wanted to limit knowledge of
this collection structure. this collection structure.
Sufficiently powerful access control mechanisms can control this risk Sufficiently powerful access control mechanisms can control this risk
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18. Internationalization Considerations 18. Internationalization Considerations
All internationalization considerations mentioned in [RFC2518] also All internationalization considerations mentioned in [RFC2518] also
apply to this document. apply to this document.
19. IANA Considerations 19. IANA Considerations
All IANA considerations mentioned in [RFC2518] also apply to this All IANA considerations mentioned in [RFC2518] also apply to this
document. document.
19.1 HTTP headers 19.1. HTTP headers
This document specifies the two new HTTP headers listed below. This document specifies the two new HTTP headers listed below.
19.1.1 Redirect-Ref 19.1.1. Redirect-Ref
Header field name: Redirect-Ref Header field name: Redirect-Ref
Applicable protocol: http Applicable protocol: http
Status: standard Status: standard
Author/Change controller: IETF Author/Change controller: IETF
Specification document: this specification (Section 12.1) Specification document: this specification (Section 12.1)
skipping to change at page 25, line 40 skipping to change at page 23, line 19
Applicable protocol: http Applicable protocol: http
Status: standard Status: standard
Author/Change controller: IETF Author/Change controller: IETF
Specification document: this specification (Section 12.2) Specification document: this specification (Section 12.2)
20. Contributors 20. Contributors
Many thanks to Jason Crawford, Jim Davis, Chuck Fay and Judith Slein Many thanks to Jason Crawford, Jim Davis, Chuck Fay, and Judith
who can take credit for big parts of the original design of this Slein, who can take credit for big parts of the original design of
specification. this specification.
21. Acknowledgements 21. Acknowledgements
This document has benefited from thoughtful discussion by Jim Amsden, This document has benefited from thoughtful discussion by Jim Amsden,
Peter Carlson, Steve Carter, Tyson Chihaya, Ken Coar, Ellis Cohen, Peter Carlson, Steve Carter, Tyson Chihaya, Ken Coar, Ellis Cohen,
Bruce Cragun, Spencer Dawkins, Mark Day, Rajiv Dulepet, David Durand, Bruce Cragun, Spencer Dawkins, Mark Day, Rajiv Dulepet, David Durand,
Lisa Dusseault, Stefan Eissing, Roy Fielding, Yaron Goland, Fred Lisa Dusseault, Stefan Eissing, Roy Fielding, Yaron Goland, Fred
Hitt, Alex Hopmann, James Hunt, Marcus Jager, Chris Kaler, Manoj Hitt, Alex Hopmann, James Hunt, Marcus Jager, Chris Kaler, Manoj
Kasichainula, Rohit Khare, Daniel LaLiberte, Steve Martin, Larry Kasichainula, Rohit Khare, Daniel LaLiberte, Steve Martin, Larry
Masinter, Jeff McAffer, Joe Orton, Surendra Koduru Reddy, Juergen Masinter, Jeff McAffer, Joe Orton, Surendra Koduru Reddy, Juergen
skipping to change at page 26, line 24 skipping to change at page 23, line 50
[RFC2518] Goland, Y., Whitehead, E., Faizi, A., Carter, S., and D. [RFC2518] Goland, Y., Whitehead, E., Faizi, A., Carter, S., and D.
Jensen, "HTTP Extensions for Distributed Authoring -- Jensen, "HTTP Extensions for Distributed Authoring --
WEBDAV", RFC 2518, February 1999. WEBDAV", RFC 2518, February 1999.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC3253] Clemm, G., Amsden, J., Ellison, T., Kaler, C., and J. [RFC3253] Clemm, G., Amsden, J., Ellison, T., Kaler, C., and J.
Whitehead, "Versioning Extensions to WebDAV (Web Whitehead, "Versioning Extensions to WebDAV (Web
Distributed Authoring and Versioning)", RFC 3253, Distributed Authoring and Versioning)", RFC 3253, March
March 2002. 2002.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66, RFC
RFC 3986, January 2005. 3986, January 2005.
Authors' Addresses Authors' Addresses
Jim Whitehead Jim Whitehead
UC Santa Cruz, Dept. of Computer Science UC Santa Cruz, Dept. of Computer Science
1156 High Street 1156 High Street
Santa Cruz, CA 95064 Santa Cruz, CA 95064
US US
Email: ejw@cse.ucsc.edu EMail: ejw@cse.ucsc.edu
Geoff Clemm Geoff Clemm
IBM IBM
20 Maguire Road 20 Maguire Road
Lexington, MA 02421 Lexington, MA 02421
US US
Email: geoffrey.clemm@us.ibm.com EMail: geoffrey.clemm@us.ibm.com
Julian F. Reschke (editor) Julian F. Reschke (editor)
greenbytes GmbH greenbytes GmbH
Salzmannstrasse 152 Hafenweg 16
Muenster, NW 48159 Muenster, NW 48155
Germany Germany
Phone: +49 251 2807760 Phone: +49 251 2807760
Fax: +49 251 2807761 Fax: +49 251 2807761
Email: julian.reschke@greenbytes.de EMail: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/ URI: http://greenbytes.de/tech/webdav/
Appendix A. Change Log (to be removed by RFC Editor before publication) Full Copyright Statement
A.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.
A.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.
A.3 Since draft-ietf-webdav-redirectref-protocol-04
More editorial fixes. Clarify that MKRESOURCE can only be used to
create redirect references (switch to new method in a future draft).
Clarify that redirect references do not have bodies.
A.4 Since draft-ietf-webdav-redirectref-protocol-05
Close (accept) issue "lc-79-accesscontrol". Add issue "rfc2606-
compliance". Close issues "lc-50-blindredirect", "lc-71-relative",
"lc-74-terminology". Update contact info for Geoff Clemm. Moved
some of the original authors names to new Contributors section. Add
and close issue "9-MKRESOURCE-vs-relative-URI". Close issue "lc-72-
trailingslash". Close issue "lc-60-ex". Update issue "lc-85-301"
with proposal. Close issue "lc-06-reftarget-relative" (9-MKRESOURCE-
vs-relative-URI was a duplicate of this one). Also remove section
9.1 (example for MKRESOURCE vs relative URIs). Add and resolve issue
"11.2-apply-to-redirect-ref-syntax" (header now has values "T" and
"F"). Also some cleanup for "rfc2606-compliance". Typo fixes. Add
and resolve "15.1-options-response".
A.5 Since draft-ietf-webdav-redirectref-protocol-06
Resolve issues "lc-19-direct-ref", "lc-28-lang", "lc-29-lang", "lc-
44-pseudo", "lc-53-s10", "lc-61-pseudo", "lc-63-move", "lc-80-i18n"
and "rfc2606-compliance". Start work on index. Add new issue
"old_clients".
A.6 Since draft-ietf-webdav-redirectref-protocol-07
Closed issue "lc-38-not-hierarchical". Cleaned up DTD fragments in
appendix. Close (reject) issues "lc-55-iana" and "lc-41-no-webdav".
Add issue "5_mkresource" and start work on MKREDIRECTREF (issue
closed, but more work on MKREDIRECTREF needs to be done for updates
and status codes other than 302). Start resolution of "lc-85-301",
replacing "302" by more generic language. Update issue "lc-57-
noautoupdate". Close issue "lc-37-integrity" (duplicate of "lc-57-
autoupdate"). Started work on "lc-85-301". Add L. Dusseault and S.
Eissing to Acknowledgments section.
A.7 Since draft-ietf-webdav-redirectref-protocol-08
Fix index entries for conditions. Open and resolve issue
"specify_safeness". Rewrite editorial section and parts of intro.
Add more clarifications for issue "lc-85-301" and close it.
A.8 Since draft-ietf-webdav-redirectref-protocol-09
Resolve issues "lc-33-forwarding", "lc-36-server" and "lc-57-
noautoupdate". Close issues "lc-48-s6", "12.1-property-name",
"3-terminology-redirectref" and "lc-58-update". Rearrange section 5
and 6. Add some more terms to index (no change tracking).
A.9 Since draft-ietf-webdav-redirectref-protocol-10
Add and resolve issues "13_allprop" and "rfc2396bis". Use the term
"Request-URI" throughout (this is what RFC2616 defines). Center some
of the artwork. Add and resolve issue "abnf".
A.10 Since draft-ietf-webdav-redirectref-protocol-11
Re-open and close issue "anbf" (implied LWS). Raise and close issue
"frag_in_target". Add precondition name for legal reftarget element
contents. Enhance index. Add and close issue "dtd-changes".
A.11 Since draft-ietf-webdav-redirectref-protocol-12
Remove RFC2616 reference from abstract. Add and resolve issue
8.1_deep_lock_complexity. Add and resolve issue headerreg (reg.
template for new HTTP headers in IANA considerations section).
Appendix B. Resolved issues (to be removed by RFC Editor before
publication)
Issues that were either rejected or resolved in this version of this
document.
B.1 8.1_deep_lock_complexity
Type: change
<http://lists.w3.org/Archives/Public/w3c-dist-auth/2005AprJun/
0141.html>
jbaumgarten@apple.com (2005-06-27): ...In particular, the failure of
locking methods that contain redirected resources would confuse our
clients. Instead, we have decided to implement a simpler redirect
capability via a custom property (not a WebDAV resource type) that is
only activated when indicated by the client request.
julian.reschke@greenbytes.de (2005-07-03): Analysis of issue in http:
//lists.w3.org/Archives/Public/w3c-dist-auth/2005JulSep/0005.html.
Resolution (2005-10-01): Make all methods except PROPFIND and REPORT
default to "Apply-To-Redirect-Ref: T".
B.2 headerreg
Type: change
julian.reschke@greenbytes.de (2005-08-24): Add RFC3864 registrations
for new HTTP headers.
Appendix C. Open issues (to be removed by RFC Editor prior to
publication)
C.1 edit
Type: edit
julian.reschke@greenbytes.de (2004-10-03): Umbrella issue for
editorial changes.
Index
A
Apply-To-Redirect-Ref header 21
C
Condition Names
DAV:legal-reftarget (pre) 10-11
DAV:locked-update-allowed (pre) 9, 11
DAV:must-be-redirectref (pre) 11
DAV:name-allowed (pre) 9
DAV:new-redirectref (post) 10
DAV:parent-resource-must-be-non-null (pre) 9
DAV:redirect-lifetime-supported (pre) 10-11
DAV:redirect-lifetime-update-supported (pre) 11
DAV:redirectref-updated (post) 12
DAV:resource-must-be-null (pre) 9
D
DAV header
compliance class 'redirectrefs' 22
DAV:legal-reftarget precondition 10-11
DAV:locked-update-allowed precondition 9, 11
DAV:mkdirectref XML element 9
DAV:mkredirectref-response XML element 9
DAV:must-be-redirectref precondition 11
DAV:name-allowed precondition 9
DAV:new-redirectref postcondition 10
DAV:parent-resource-must-be-non-null precondition 9
DAV:permanent XML element 9, 21
DAV:redirect-lifetime property 21
DAV:redirect-lifetime XML element 9, 21
DAV:redirect-lifetime-supported precondition 10-11
DAV:redirect-lifetime-update-supported precondition 11
DAV:redirectref resource type 22
DAV:redirectref-updated postcondition 12
DAV:reftarget property 22
DAV:reftarget XML element 9
DAV:resource-must-be-null precondition 9
DAV:temporary XML element 9, 21
DAV:updateredirectref-response XML element 11
H
Headers
Apply-To-Redirect-Ref 21
Redirect-Ref 21
M
Methods
MKREDIRECTREF 8
UPDATEREDIRECTREF 10
MKREDIRECTREF method 8
N
Non-Reference Resource 6
P
Properties
DAV:redirect-lifetime 21
DAV:reftarget 22
R
Redirect Reference Resource 6
Redirect-Ref header 21
Resource Types
DAV:redirectref 22
T Copyright (C) The Internet Society (2006).
Target Resource 7
U This document is subject to the rights, licenses and restrictions
UPDATEREDIRECTREF method 10 contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
X This document and the information contained herein are provided on an
XML elements "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
DAV:mkdirectref 9 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
DAV:mkredirectref-response 9 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
DAV:permanent 9, 21 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
DAV:redirect-lifetime 9, 21 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
DAV:reftarget 9 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
DAV:temporary 9, 21
DAV:updateredirectref-response 11
Intellectual Property Statement Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
skipping to change at page 32, line 29 skipping to change at page 25, line 45
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Disclaimer of Validity Acknowledgement
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is provided by the IETF
Internet Society. Administrative Support Activity (IASA).
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