| WEBDAV Working Group | J. Whitehead |
| Internet-Draft | U.C. Santa Cruz |
| Intended status: Standards Track | G. Clemm |
| Expires: October 7, 2004 | IBM |
| J. Reschke, Editor | |
| greenbytes | |
| April 5, 2004 |
This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she become aware will be disclosed, in accordance with RFC 3668.¶
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 October 7, 2004.¶
Copyright © The Internet Society (2004). All Rights Reserved.¶
This specification defines redirect reference resources. A redirect reference resource is a resource whose default response is an HTTP/1.1 <ed:replace>
Distribution of this document is unlimited. Please send comments to the Distributed Authoring and Versioning (WebDAV) working group at w3c-dist-auth@w3.org, which may be joined by sending a message with subject "subscribe" to w3c-dist-auth-request@w3.org.¶
Discussions of the WEBDAV working group are archived at URL: http://lists.w3.org/Archives/Public/w3c-dist-auth/.¶
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:¶
<ed:replace>
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 <ed:replace>
A redirect reference is a resource with properties but no body of its own. Properties of a redirect reference resource can contain such information as who created the reference, when, and why. Since redirect reference resources are implemented using HTTP <ed:replace>
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 1 discusses how to create a redirect reference resource. Section 5 defines the semantics of existing methods when applied to redirect reference resources, and Section 6 discusses their semantics when applied to collections that contain redirect reference resources. Sections 7 through 9 discuss several other issues raised by the existence of redirect reference resources. Sections 10 through 12 define the new headers, properties, and XML elements required to support redirect reference resources. Section 13 discusses capability discovery. Sections 14 through 16 present the security, internationalization, and IANA concerns raised by this specification. The remaining sections provide a variety of supporting information.¶
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 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 ¶
Non-Reference Resource ¶
Target Resource ¶
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 10.1 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 1.2 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 11.1 below.¶
Since a redirect reference resource is a resource, 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 10.2 below) is provided so that referencing-aware clients can control whether an operation is applied to the redirect reference resource or standard HTTP/WebDAV behaviour (redirection with a 3xx status code) should occur. 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.¶
The new MKRESOURCE method is used to create new redirect reference resources. 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 11.1. 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.¶
The MKRESOURCE method requests the creation of a redirect reference resource and initialization of its properties in one atomic operation.¶
Preconditions: ¶
Request Marshalling:
Postconditions:
Response Marshalling:
>> Request:
MKRESOURCE /~whitehead/dav/spec08.ref HTTP/1.1
Host: www.example.com
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>/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 http://www.example.com/~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.example.com/i-d/draft-webdav-protocol-08.txt. The redirect reference resource's DAV:resourcetype property is set to DAV:redirectref.¶
The MKREDIRECTREF method requests the creation of a redirect reference resource.¶
If a MKREDIRECTREF request fails, the server state preceding the request MUST be restored.¶
Responses from a MKREDIRECTREF request MUST NOT be cached, as MKREDIRECTREF has non-idempotent semantics.¶
Marshalling: ¶
<!ELEMENT mkredirectref (reftarget, redirect-lifetime?)> <!ELEMENT reftarget (href)> <!ELEMENT redirect-lifetime (permanent | temporary)> <!ELEMENT permanent EMPTY> <!ELEMENT temporary EMPTY>
<!ELEMENT mkredirectref-response ANY>
Preconditions: ¶
Postconditions: ¶
>> Request:
MKREDIRECTREF /~whitehead/dav/spec08.ref HTTP/1.1
Host: www.example.com
Content-Type: text/xml; charset="utf-8"
Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?>
<D:mkredirectref xmlns:D="DAV:">
<D:reftarget>
<D:href>/i-d/draft-webdav-protocol-08.txt</D:href>
</D:reftarget>
</D:mkredirectref>
>> Response:
HTTP/1.1 201 Created
This request resulted in the creation of a new redirect reference resource at http://www.example.com/~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.example.com/i-d/draft-webdav-protocol-08.txt. The redirect reference resource's DAV:resourcetype property is set to DAV:redirectref.¶
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 <ed:replace>
A reference-aware WebDAV client 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: T" header in order to operate on the reference resource itself. In this case, the request MUST be applied to the reference resource itself, and a <ed:replace>
As redirect references do not have bodies, GET and PUT requests with "Apply-To-Redirect-Ref: T" MUST fail with status 403 (forbidden).¶
Consistent with the rules in Section 5, the response for each redirect reference encountered while processing a collection MUST be a <ed:replace>
The Apply-To-Redirect-Ref header (defined in Section 10.2) 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.¶
An attempt to lock (with Depth: infinity) a collection that contains redirect references without specifying "Apply-To-Redirect-Ref: T" will always fail. The Multi-Status response will contain a <ed:replace>
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.¶
Suppose a PROPFIND request with Depth: infinity is submitted to the following collection, with the members shown here:¶
/MyCollection/
(non-reference resource) diary.html
(redirect reference resource) nunavut
>> Request:
PROPFIND /MyCollection/ HTTP/1.1
Host: example.com
Depth: infinity
Apply-To-Redirect-Ref: F
Content-Type: text/xml
Content-Length: xxxx
<?xml version="1.0" ?>
<D:propfind xmlns:D="DAV: ">
<D:prop xmlns:J="http://example.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://example.com/jsprops/">
<D:response>
<D:href>/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>/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>/MyCollection/nunavut</D:href>
<D:status>HTTP/1.1 302 Found</D:status>
<D:location>
<D:href>http://example.ca/art/inuit/</D:href>
</D:location>
</D:response>
</D:multistatus>
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 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:location extension element 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.)¶
Suppose a PROPFIND request with "Apply-To-Redirect-Ref: T" and Depth: infinity is submitted to the following collection, with the members shown here:¶
/MyCollection/
(non-reference resource) diary.html
(redirect reference resource) nunavut
>> Request:
PROPFIND /MyCollection/ HTTP/1.1
Host: example.com
Depth: infinity
Apply-To-Redirect-Ref: T
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>/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>/MyCollection/diary.html</D:href>
<D:propstat>
<D:prop>
<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>/MyCollection/nunavut</D:href>
<D:propstat>
<D:prop>
<D:resourcetype><D:redirectref/></D:resourcetype>
<D:reftarget>
<D:href>http://example.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: T" header is present, the response shows the properties of the redirect reference resource in the collection rather than reporting a 302 status.¶
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: example.com Depth: infinity Destination: http://example.com/OtherCollection/
>> Response:
HTTP/1.1 207 Multi-Status
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>/MyCollection/nunavut</D:href>
<D:status>HTTP/1.1 302 Found</D:status>
<D:location>
<D:href>http://example.com//Someplace/nunavut.map</D:href>
</D:location>
</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
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: example.com Apply-To-Redirect-Ref: F Content-Type: text/xml <?xml version="1.0" ?> <D:lockinfo xmlns:D="DAV:"> <D:lockscope><D:exclusive/></D:lockscope> <D:locktype><D:write/></D:locktype> </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>/MyCollection/</D:href>
<D:status>HTTP/1.1 424 Failed Dependency</D:status>
</D:response>
<D:response>
<D:href>/MyCollection/diary.html</D:href>
<D:status>HTTP/1.1 424 Failed Dependency</D:status>
</D:response>
<D:response>
<D:href>/MyCollection/nunavut</D:href>
<D:status>HTTP/1.1 302 Found</D:status>
<D:location>
<D:href>http://example.ca/art/inuit/</D:href>
</D:location>
</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 element 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 other members).¶
Operations on targets of redirect reference resources have no effect on the reference resource.¶
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 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.¶
>> Request:
PROPFIND /geog/ HTTP/1.1
Host: example.com
Apply-To-Redirect-Ref: T
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>
<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://example.com/geog/stats.html. This is the base URI for resolving the relative URI in reftarget. The absolute URI of reftarget is http://example.com/geog/statistics/population/1997.html.¶
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 SHOULD be a <ed:replace>
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 <ed:replace>
Redirect-Ref = "Redirect-Ref:" (absoluteURI | relativeURI)
; see sections 3 and 5 of [RFC2396]
The Redirect-Ref header is used in all <ed:replace>
Apply-To-Redirect-Ref = "Apply-To-Redirect-Ref" ":" ("T" | "F")
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", the request MUST be applied to the reference resource itself, and a <ed:replace>
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 MUST ignore it.¶
<!ELEMENT reftarget href >
The properties defined below are REQUIRED on redirect reference resources.¶
This property provides information about the lifetime of a redirect. It can either be DAV:permanent (HTTP status 301) or DAV:temporary (HTTP status 302). Future protocols MAY define additional values.¶
<!ELEMENT redirect-lifetime (permanent | temporary)> <!ELEMENT permanent EMPTY> <!ELEMENT temporary EMPTY>
This property 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 MKREDIRECTREF request. The value is a DAV:href element containing the URI of the target resource.¶
<!ELEMENT reftarget href >
<!ELEMENT redirectref EMPTY >
As described in Section 6, the DAV:location element 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.¶
Consequently, the definition of the DAV:response XML element changes to the following:¶
<!ELEMENT response (href, ((href*, status)|(propstat+)),
responsedescription?, location?) >
<!ELEMENT location (href) >
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 header and by listing the <ed:replace>
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.¶
>> Request:
OPTIONS /somecollection/someresource HTTP/1.1 Host: example.org
>> Response:
<ed:replace>HTTP/1.1 200 OK Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE Allow: MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, MKRESOURCE DAV: 1, 2, redirectrefs
HTTP/1.1 200 OK Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE Allow: MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, MKREDIRECTREF 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 <ed:replace>
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.¶
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.)¶
Although redirect loops were already possible in HTTP 1.1, the introduction of the <ed:replace>
Denial of service attacks were already possible by posting URLs that were intended for limited use at heavily used Web sites. The introduction of <ed:replace>
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.¶
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.)¶
This risk is no greater than the similar risk posed by HTML links.¶
Many thanks to Jason Crawford, Jim Davis, Chuck Fay and Judith Slein who can take credit for big parts of the original design of this specification.¶
This document 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, <ed:replace>
<!-- 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?) >
<!-- Property Elements from Section 1 -->
<!ELEMENT reftarget href> <!ELEMENT location href>
<!-- XML Elements from Section 11-->
<!ELEMENT redirectref EMPTY >
<!-- Changes to the DAV:response Element from Section 12 -->
<!ELEMENT response (href, ((href*, status)|(propstat+)),
responsedescription?, location?) >
<!ELEMENT location (href) >
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.¶
Added Joe Orton and Juergen Reuter to Acknowledgements section. Close more editorial issues. Remove dependencies on BIND spec.¶
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.¶
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".¶
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".¶
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.¶
Copyright © The Internet Society (2004).¶
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.¶
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.¶
The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in 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 made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79.¶
Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr.¶
The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org.¶