draft-ietf-webdav-bind-00.txt   draft-ietf-webdav-bind-01.txt 
INTERNET-DRAFT G. Clemm INTERNET-DRAFT G. Clemm
draft-ietf-webdav-bind-00 Rational Software draft-ietf-webdav-bind-01 Rational Software
J. Crawford J. Crawford
IBM Research IBM Research
J. Reschke J. Reschke
Greenbytes Greenbytes
J. Slein J. Slein
Xerox Xerox
E.J. Whitehead E.J. Whitehead
U.C. Santa Cruz U.C. Santa Cruz
Expires April 2, 2002 October 2, 2001 Expires August 7, 2003 February 7, 2003
Binding Extensions to WebDAV Binding Extensions to WebDAV
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with all This document is an Internet-Draft and is in full conformance with all
provisions of RFC 2026, Section 10. provisions of RFC 2026, Section 10.
Internet-Drafts are working documents of the Internet Engineering Task Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups. Note that other groups Force (IETF), its areas, and its working groups. Note that other groups
may also distribute working documents as Internet-Drafts. may also distribute working documents as Internet-Drafts.
skipping to change at line 46 skipping to change at line 46
Abstract Abstract
This specification defines bindings, and the BIND method for creating This specification defines bindings, and the BIND method for creating
multiple bindings to the same resource. Creating a new binding to a multiple bindings to the same resource. Creating a new binding to a
resource causes at least one new URI to be mapped to that resource. resource causes at least one new URI to be mapped to that resource.
Servers are required to insure the integrity of any bindings that they Servers are required to insure the integrity of any bindings that they
allow to be created. allow to be created.
Clemm, et al. [Page 1] Clemm, et al. [Page 1]
Table of Contents Table of Contents
1 INTRODUCTION...........................................3 1 INTRODUCTION............................................3
1.1 Terminology...........................................4 1.1 Terminology...........................................4
1.2 Rationale for Distinguishing Bindings from URI Mappings6 1.2 Rationale for Distinguishing Bindings from URI Mappings
......................................................6
2 OVERVIEW OF BINDINGS...................................6 2 OVERVIEW OF BINDINGS....................................6
2.1 Bindings to Collections...............................7 2.1 Bindings to Collections...............................7
2.2 URI Mappings Created by a new Binding.................7 2.2 URI Mappings Created by a new Binding.................7
2.3 DELETE and Bindings...................................8 2.3 DELETE and Bindings...................................8
2.4 COPY and Bindings.....................................9 2.4 COPY and Bindings.....................................9
2.5 MOVE and Bindings....................................10 2.5 MOVE and Bindings.....................................9
2.6 Determining Whether Two Bindings Are to the Same Resource..........10 2.6 Determining Whether Two Bindings Are to the Same Resource
.....................................................10
2.7 Discovering the Bindings to a Resource...............11 2.7 Discovering the Bindings to a Resource...............11
3 PROPERTIES............................................11 3 PROPERTIES.............................................11
3.1 DAV:resource-id Property.............................11 3.1 DAV:resource-id Property.............................12
3.2 DAV:parent-set Property..............................12 3.2 DAV:parent-set Property..............................12
4 BIND METHOD...........................................12 4 BIND METHOD............................................12
4.1 Example: BIND........................................13 4.1 Example: BIND........................................14
5 ADDITIONAL STATUS CODES...............................14 5 ADDITIONAL STATUS CODES................................14
5.1 506 Loop Detected....................................14 5.1 506 Loop Detected....................................14
6 SECURITY CONSIDERATIONS...............................15 6 SECURITY CONSIDERATIONS................................16
6.1 Privacy Concerns.....................................15 6.1 Privacy Concerns.....................................16
6.2 Redirect Loops.......................................15 6.2 Redirect Loops.......................................16
6.3 Bindings, and Denial of Service......................16 6.3 Bindings, and Denial of Service......................16
6.4 Private Locations May Be Revealed....................16 6.4 Private Locations May Be Revealed....................16
6.5 DAV:parent-set and Denial of Service.................16 6.5 DAV:parent-set and Denial of Service.................17
7 INTERNATIONALIZATION CONSIDERATIONS...................16 7 INTERNATIONALIZATION CONSIDERATIONS....................17
8 IANA CONSIDERATIONS...................................16 8 IANA CONSIDERATIONS....................................17
9 INTELLECTUAL PROPERTY.................................16 9 INTELLECTUAL PROPERTY..................................17
10 ACKNOWLEDGEMENTS.....................................17 10 ACKNOWLEDGEMENTS.....................................17
11 REFERENCES...........................................17 11 REFERENCES...........................................18
12 AUTHORS' ADDRESSES...................................18 12 AUTHORS' ADDRESSES...................................18
Clemm, et al. [Page 2] Clemm, et al. [Page 2]
1 INTRODUCTION 1 INTRODUCTION
This specification extends the WebDAV Distributed Authoring This specification extends the WebDAV Distributed Authoring
Protocol to enable clients to create new access paths to existing Protocol 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:
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Binding Binding
A relation between a single path segment (in a collection) and a A relation between a single path segment (in a collection) and a
resource. A binding is part of the state of a collection. If two resource. A binding is part of the state of a collection. If two
different collections contain a binding between the same path different collections contain a binding between the same path
segment and the same resource, these are two distinct bindings. So segment and the same resource, these are two distinct bindings. So
for a collection C, a path segment S, and a resource R, the binding for a collection C, a path segment S, and a resource R, the binding
can be thought of as C:(S -> R). Bindings create URI mappings, and can be thought of as C:(S -> R). Bindings create URI mappings, and
hence allow requests to be sent to a single resource from multiple hence allow requests to be sent to a single resource from multiple
locations in a URI namespace. For example, given a collection C locations in a URI namespace. For example, given a collection C
(accessible through the URI http://www.srv.com/coll/), a path (accessible through the URI http://www.example.com/coll/), a path
segment S (equal to "foo.html"), and a resource R, then creating segment S (equal to "foo.html"), and a resource R, then creating
the binding C: (S -> R) makes it possible to use the URI the binding C: (S -> R) makes it possible to use the URI
http://www.srv.com/coll/foo.html to access R. http://www.example.com/coll/foo.html to access R.
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Collection Collection
A resource that contains, as part of its state, a set of bindings A resource that contains, as part of its state, a set of bindings
that identify internal member resources. that identify internal member resources.
Clemm, et al. [Page 5] Clemm, et al. [Page 5]
Internal Member URI Internal Member URI
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1.2 Rationale for Distinguishing Bindings from URI Mappings 1.2 Rationale for Distinguishing Bindings from URI Mappings
In [RFC2518], the state of a collection is defined as containing a In [RFC2518], the state of a collection is defined as containing a
list of internal member URIs. If there are multiple mappings to a list of internal member URIs. If there are multiple mappings to a
collection, then the state of the collection is different when you collection, then the state of the collection is different when you
refer to it via a different URI. This is undesirable, since ideally refer to it via a different URI. This is undesirable, since ideally
a collection's membership should remain the same, independent of a collection's membership should remain the same, independent of
which URI was used to reference it. which URI was used to reference it.
The notion of binding is introduced to separate the final segment The notion of binding is introduced to separate the final segment
of a URI from its parent collections contribution. This done, a of a URI from its parent collection's contribution. This done, a
collection can be defined as containing a set of bindings, thus collection can be defined as containing a set of bindings, thus
permitting new mappings to a collection without modifying its permitting new mappings to a collection without modifying its
membership. The authors of this specification anticipate and membership. The authors of this specification anticipate and
recommend that future revisions of [RFC2518] will update the recommend that future revisions of [RFC2518] will update the
definition of the state of a collection to correspond to the definition of the state of a collection to correspond to the
definition in this document. definition in this document.
2 OVERVIEW OF BINDINGS 2 OVERVIEW OF BINDINGS
Bindings are part of the state of a collection. They define the Bindings are part of the state of a collection. They define the
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binding. binding.
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2.1 Bindings to Collections 2.1 Bindings to Collections
Bindings to collections can result in loops, which servers MUST Bindings to collections can result in loops, which servers MUST
detect when processing "Depth: infinity" requests. It is sometimes detect when processing "Depth: infinity" requests. It is sometimes
possible to complete an operation in spite of the presence of a possible to complete an operation in spite of the presence of a
loop. However, the 506 (Loop Detected) status code is defined in loop. However, the 506 (Loop Detected) status code is defined in
Section 5 for use in contexts where an operation is terminated Section 5 for use in contexts where an operation is terminated
because a loop was encountered. Servers MUST allow loops to be because a loop was encountered.
created.
Creating a new binding to a collection makes each resource Creating a new binding to a collection makes each resource
associated with a binding in that collection accessible via a new associated with a binding in that collection accessible via a new
URI, and thus creates new URI mappings to those resources but no URI, and thus creates new URI mappings to those resources but no
new bindings. new bindings.
For example, suppose a new binding CollY is created for collection For example, suppose a new binding CollY is created for collection
C1 in the figure below. It immediately becomes possible to access C1 in the figure below. It immediately becomes possible to access
resource R1 using the URI /CollY/x.gif and to access resource R2 resource R1 using the URI /CollY/x.gif and to access resource R2
using the URI /CollY/y.jpg, but no new bindings for these child using the URI /CollY/y.jpg, but no new bindings for these child
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| \ | \
+-------------+ +-------------+ +-------------+ +-------------+
| Resource R1 | | Resource R2 | | Resource R1 | | Resource R2 |
+-------------+ +-------------+ +-------------+ +-------------+
2.2 URI Mappings Created by a new Binding 2.2 URI Mappings Created by a new Binding
Suppose a binding from "Binding-Name" to resource R to be added to Suppose a binding from "Binding-Name" to resource R to be added to
a collection, C. Then if C-MAP is the set of URI's that were a collection, C. Then if C-MAP is the set of URI's that were
mapped to C before the BIND request, then for each URI "C-URI" in mapped to C before the BIND request, then for each URI "C-URI" in
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C-MAP, the URI "C-URI/Binding-Name" is mapped to resource R C-MAP, the URI "C-URI/Binding-Name" is mapped to resource R
following the BIND request. following the BIND request.
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For example, if a binding from "foo.html" to R is added to a For example, if a binding from "foo.html" to R is added to a
collection C, and if the following URI's are mapped to C: collection C, and if the following URI's are mapped to C:
http://www.fuzz.com/A/1/ http://www.example.com/A/1/
http://fuzz.com/A/one/ http://example.com/A/one/
then the following new mappings to R are introduced: then the following new mappings to R are introduced:
http://www.fuzz.com/A/1/foo.html http://www.example.com/A/1/foo.html
http://fuzz.com/A/one/foo.html http://example.com/A/one/foo.html
Note that if R is a collection, additional URI mappings are created Note that if R is a collection, additional URI mappings are created
to the descendents of R. Also, note that if a binding is made in to the descendents of R. Also, note that if a binding is made in
collection C to C itself (or to a parent of C), an infinite number collection C to C itself (or to a parent of C), an infinite number
of mappings are introduced. of mappings are introduced.
For example, if a binding from "myself" to C is then added to C, For example, if a binding from "myself" to C is then added to C,
the following infinite number of additional mappings to C are the following infinite number of additional mappings to C are
introduced: introduced:
http://www.fuzz.com/A/1/myself http://www.example.com/A/1/myself
http://www.fuzz.com/A/1/myself/myself http://www.example.com/A/1/myself/myself
... ...
and the following infinite number of additional mappings to R are and the following infinite number of additional mappings to R are
introduced: introduced:
http://www.fuzz.com/A/1/myself/foo.html http://www.example.com/A/1/myself/foo.html
http://www.fuzz.com/A/1/myself/myself/foo.html http://www.example.com/A/1/myself/myself/foo.html
... ...
2.3 DELETE and Bindings 2.3 DELETE and Bindings
The DELETE method was originally defined in [RFC2616]. This section The DELETE method was originally defined in [RFC2616]. This section
redefines the behavior of DELETE in terms of bindings, an redefines the behavior of DELETE in terms of bindings, an
abstraction not available when writing [RFC2616]. [RFC2616] states abstraction not available when writing [RFC2616]. [RFC2616] states
that "the DELETE method requests that the origin server delete the that "the DELETE method requests that the origin server delete the
resource identified by the Request-URI." Because [RFC2616] did not resource identified by the Request-URI." Because [RFC2616] did not
distinguish between bindings and resources, the intent of its distinguish between bindings and resources, the intent of its
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The DELETE method requests that the server remove the binding The DELETE method requests that the server remove the binding
between the resource identified by the Request-URI and the binding between the resource identified by the Request-URI and the binding
name, the last path segment of the Request-URI. The binding MUST be name, the last path segment of the Request-URI. The binding MUST be
removed from its parent collection, identified by the Request-URI removed from its parent collection, identified by the Request-URI
minus its trailing slash (if present) and final segment. minus its trailing slash (if present) and final segment.
Once a resource is unreachable by any URI mapping, the server MAY Once a resource is unreachable by any URI mapping, the server MAY
reclaim system resources associated with that resource. If DELETE reclaim system resources associated with that resource. If DELETE
removes a binding to a resource, but there remain URI mappings to removes a binding to a resource, but there remain URI mappings to
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that resource, the server MUST NOT reclaim system resources that resource, the server MUST NOT reclaim system resources
associated with the resource. associated with the resource.
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Although [RFC2518] allows a DELETE to be a non-atomic operation, Although [RFC2518] allows a DELETE to be a non-atomic operation,
the DELETE operation defined here is atomic. In particular, a the DELETE operation defined here is atomic. In particular, a
DELETE on a hierarchy of resources is simply the removal of a DELETE on a hierarchy of resources is simply the removal of a
binding to the collection identified by the Request-URI, and so is binding to the collection identified by the Request-URI, and so is
a single (and therefore atomic) operation. a single (and therefore atomic) operation.
Section 8.6.1 of [RFC2518] states that during DELETE processing, a Section 8.6.1 of [RFC2518] states that during DELETE processing, a
server "MUST remove any URI for the resource identified by the server "MUST remove any URI for the resource identified by the
Request-URI from collections which contain it as a member." Request-URI from collections which contain it as a member."
Servers that support bindings MUST NOT follow this requirement. Servers that support bindings MUST NOT follow this requirement.
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+---------------------+ +------------------------+ +---------------------+ +------------------------+
It might be thought that a COPY request with "Depth: 0" on a It might be thought that a COPY request with "Depth: 0" on a
collection would duplicate its bindings, since bindings are part of collection would duplicate its bindings, since bindings are part of
the collection's state. This is not the case, however. The the collection's state. This is not the case, however. The
definition of Depth in [RFC2518] makes it clear that a "Depth: 0" definition of Depth in [RFC2518] makes it clear that a "Depth: 0"
request does not apply to a collection's members. Consequently, a request does not apply to a collection's members. Consequently, a
COPY with "Depth: 0" does not duplicate the bindings contained by COPY with "Depth: 0" does not duplicate the bindings contained by
the collection. the collection.
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2.5 MOVE and Bindings 2.5 MOVE and Bindings
The MOVE method has the effect of creating a new binding to a The MOVE method has the effect of creating a new binding to a
resource (at the Destination), and removing an existing binding (at resource (at the Destination), and removing an existing binding (at
the Request-URI). The name of the new binding is the last path the Request-URI). The name of the new binding is the last path
segment of the Destination header, and the new binding is added to segment of the Destination header, and the new binding is added to
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its parent collection, identified by the Destination header minus its parent collection, identified by the Destination header minus
its trailing slash (if present) and final segment. its trailing slash (if present) and final segment.
As an example, suppose that a MOVE is issued to URI 3 for resource As an example, suppose that a MOVE is issued to URI 3 for resource
R below (which is also mapped to URI 1 and URI 2), with the R below (which is also mapped to URI 1 and URI 2), with the
Destination header set to URIX. After successful completion of the Destination header set to URIX. After successful completion of the
MOVE operation, a new binding has been created which creates at MOVE operation, a new binding has been created which creates at
least the URI mapping between URIX and resource R (although other least the URI mapping between URIX and resource R (although other
URI mappings may also have been created). The binding URI mappings may also have been created). The binding
corresponding to the final segment of URI 3 has been removed, which corresponding to the final segment of URI 3 has been removed, which
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+---------------------+ +---------------------+
Although [RFC2518] allows a MOVE on a collection to be a non-atomic Although [RFC2518] allows a MOVE on a collection to be a non-atomic
operation, the MOVE operation defined here MUST be atomic. Even operation, the MOVE operation defined here MUST be atomic. Even
when the Request-URI identifies a collection, the MOVE operation when the Request-URI identifies a collection, the MOVE operation
involves only removing one binding to that collection and adding involves only removing one binding to that collection and adding
another. There are no operations on bindings to any of its another. There are no operations on bindings to any of its
children, so the case of MOVE on a collection is the same as the children, so the case of MOVE on a collection is the same as the
case of MOVE on a non-collection resource. Both are atomic. case of MOVE on a non-collection resource. Both are atomic.
2.5.1Additional MOVE Semantics
Additional Preconditions:
(DAV:cycle-allowed): If the request-URL identifies a collection,
and the parent of the Destination is that collection or is a member
of that collection, the server MUST support cycles in the URL
namespace.
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2.6 Determining Whether Two Bindings Are to the Same Resource 2.6 Determining Whether Two Bindings Are to the Same Resource
It is useful to have some way of determining whether two bindings It is useful to have some way of determining whether two bindings
are to the same resource. Two resources might have identical are to the same resource. Two resources might have identical
contents and properties, but not be the same resource (e.g. an contents and properties, but not be the same resource (e.g. an
update to one resource does not affect the other resource). update to one resource does not affect the other resource).
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The REQUIRED DAV:resource-id property defined in Section 3.1 is a The REQUIRED DAV:resource-id property defined in Section 3.1 is a
resource identifier, which MUST be unique across all resources for resource identifier, which MUST be unique across all resources for
all time. If the values of DAV:resource-id returned by PROPFIND all time. If the values of DAV:resource-id returned by PROPFIND
requests through two bindings are identical, the client can be requests through two bindings are identical, the client can be
assured that the two bindings are to the same resource. assured that the two bindings are to the same resource.
The DAV:resource-id property is created, and its value assigned, The DAV:resource-id property is created, and its value assigned,
when the resource is created. The value of DAV:resource-id MUST when the resource is created. The value of DAV:resource-id MUST
NOT be changed. Even after the resource is no longer accessible NOT be changed. Even after the resource is no longer accessible
through any URI, that value MUST NOT be reassigned to another through any URI, that value MUST NOT be reassigned to another
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whether to support the DAV:parent-set property, server implementers whether to support the DAV:parent-set property, server implementers
/ administrators should balance the benefits it provides against / administrators should balance the benefits it provides against
the cost of maintaining the property and the security risks the cost of maintaining the property and the security risks
enumerated in Sections 6.4 and 6.5. enumerated in Sections 6.4 and 6.5.
3 PROPERTIES 3 PROPERTIES
The bind feature introduces the following properties for a The bind feature introduces the following properties for a
resource. resource.
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3.1 DAV:resource-id Property 3.1 DAV:resource-id Property
The DAV:resource-id property is a REQUIRED property that enables The DAV:resource-id property is a REQUIRED property that enables
clients to determine whether two bindings are to the same resource. clients to determine whether two bindings are to the same resource.
The value of DAV:resource-id is a URI, and may use any registered The value of DAV:resource-id is a URI, and may use any registered
URI scheme that guarantees the uniqueness of the value across all URI scheme that guarantees the uniqueness of the value across all
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resources for all time (e.g. the opaquelocktoken: scheme defined in resources for all time (e.g. the opaquelocktoken: scheme defined in
[RFC2518]). [RFC2518]).
<!ELEMENT resource-id (href)> <!ELEMENT resource-id (href)>
3.2 DAV:parent-set Property 3.2 DAV:parent-set Property
The DAV:parent-set property is an OPTIONAL property that enables The DAV:parent-set property is an OPTIONAL property that enables
clients to discover what collections contain a binding to this clients to discover what collections contain a binding to this
resource (i.e. what collections have that resource as an internal resource (i.e. what collections have that resource as an internal
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request MUST fail. Note that it is especially difficult to request MUST fail. Note that it is especially difficult to
maintain the integrity of cross-server bindings. Unless the server maintain the integrity of cross-server bindings. Unless the server
where the resource resides knows about all bindings on all servers where the resource resides knows about all bindings on all servers
to that resource, it may unwittingly destroy the resource or make to that resource, it may unwittingly destroy the resource or make
it inaccessible without notifying another server that manages a it inaccessible without notifying another server that manages a
binding to the resource. For example, if server A permits creation binding to the resource. For example, if server A permits creation
of a binding to a resource on server B, server A must notify server of a binding to a resource on server B, server A must notify server
B about its binding and must have an agreement with B that B will B about its binding and must have an agreement with B that B will
not destroy the resource while A's binding exists. Otherwise not destroy the resource while A's binding exists. Otherwise
server B may receive a DELETE request that it thinks removes the server B may receive a DELETE request that it thinks removes the
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last binding to the resource and destroy the resource while A's last binding to the resource and destroy the resource while A's
binding still exists. Status code 507 (Cross-server Binding binding still exists. Status code 507 (Cross-server Binding
Forbidden) is defined in Section 5.1 for cases where servers fail Forbidden) is defined in Section 5.1 for cases where servers fail
cross-server BIND requests because they cannot guarantee the cross-server BIND requests because they cannot guarantee the
integrity of cross-server bindings. integrity of cross-server bindings.
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By default, if there already is a binding for the specified segment By default, if there already is a binding for the specified segment
in the collection, the new binding replaces the existing binding. in the collection, the new binding replaces the existing binding.
This default binding replacement behavior can be overridden using This default binding replacement behavior can be overridden using
the Overwrite header defined in Section 9.6 of [RFC2518]. the Overwrite header defined in Section 9.6 of [RFC2518].
Marshalling: Marshalling:
The request MAY include an Overwrite header. The request MAY include an Overwrite header.
The request body MUST be a DAV:bind XML element. The request body MUST be a DAV:bind XML element.
<!ELEMENT bind ANY> <!ELEMENT bind ANY>
<!ELEMENT bind (segment, href)> <!ELEMENT bind (segment, href)>
If the request succeeds, the server MUST return 201 (Created) when
a new binding was created and 204 (No Content) when an existing
binding was replaced.
If a response body for a successful request is included, it MUST be If a response body for a successful request is included, it MUST be
a DAV:bind-response XML element. Note that this document does not a DAV:bind-response XML element. Note that this document does not
define any elements for the BIND response body, but the DAV:bind- define any elements for the BIND response body, but the DAV:bind-
response element is defined to ensure interoperability between response element is defined to ensure interoperability between
future extensions that do define elements for the BIND response future extensions that do define elements for the BIND response
body. body.
<!ELEMENT bind-response ANY> <!ELEMENT bind-response ANY>
Preconditions: Preconditions:
(DAV:bind-into-collection): The Request-URL MUST identify a (DAV:bind-into-collection): The Request-URL MUST identify a
collection. collection.
(DAV:bind-source-exists): The DAV:href element MUST identify a
resource.
(DAV:binding-allowed): The resource identified by the DAV:href
supports multiple bindings to it.
(DAV:cross-server-binding): If the resource identified by the (DAV:cross-server-binding): If the resource identified by the
DAV:href element in the request body is on another server from the DAV:href element in the request body is on another server from the
collection identified by the request-URL, the server MUST support collection identified by the request-URL, the server MUST support
cross-server bindings. cross-server bindings.
(DAV:name-allowed): The name specified by the DAV:segment is
available for use as a new binding name.
(DAV:can-overwrite): If the collection already contains a binding (DAV:can-overwrite): If the collection already contains a binding
with the specified path segment, and if an Overwrite header is with the specified path segment, and if an Overwrite header is
included, the value of the Overwrite header MUST be "T". included, the value of the Overwrite header MUST be "T".
Clemm, et al. [Page 13]
(DAV:cycle-allowed): If the DAV:href element identifies a
collection, and if the request-URL identifies a collection that is
a member of that collection, the server MUST support cycles in the
URL namespace.
Postconditions: Postconditions:
(DAV:new-binding): The collection MUST have a binding that maps the (DAV:new-binding): The collection MUST have a binding that maps the
segment specified in the DAV:segment element in the request body, segment specified in the DAV:segment element in the request body,
to the resource identified by the DAV:href element in the request to the resource identified by the DAV:href element in the request
body. body.
4.1 Example: BIND 4.1 Example: BIND
>> Request: >> Request:
BIND /coll HTTP/1.1 BIND /coll HTTP/1.1
Host: www.somehost.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" ?>
Clemm, et al. [Page 13]
<D:bind xmlns:D="DAV:"> <D:bind xmlns:D="DAV:">
<D:segment>bar.html</D:segment> <D:segment>bar.html</D:segment>
<D:href>http://www.somehost.com/coll</D:href> <D:href>http://www.example.com/coll/foo.html</D:href>
</D:bind> </D:bind>
>> Response: >> Response:
HTTP/1.1 201 Created HTTP/1.1 200 OK
The server added a new binding to the collection, The server added a new binding to the collection,
"http://www.somehost.com/coll", associating "bar.html" with the "http://www.example.com/coll", associating "bar.html" with the
resource identified by the URL resource identified by the URL
"http://www.somehost.com/coll/foo.html". Clients can now use the "http://www.example.com/coll/foo.html". Clients can now use the
URL "http://www.somehost.com/coll/bar.html", to submit requests to URL "http://www.example.com/coll/bar.html", to submit requests to
that resource. that resource.
5 ADDITIONAL STATUS CODES 5 ADDITIONAL STATUS CODES
5.1 506 Loop Detected 5.1 506 Loop Detected
The 506 (Loop Detected) status code indicates that the server The 506 (Loop Detected) status code indicates that the server
terminated an operation because it encountered an infinite loop terminated an operation because it encountered an infinite loop
while processing a request with "Depth: infinity". while processing a request with "Depth: infinity".
When this status code is the top-level status code for the When this status code is the top-level status code for the
operation, it indicates that the entire operation failed. operation, it indicates that the entire operation failed.
Clemm, et al. [Page 14]
When this status code occurs inside a multi-status response, it When this status code occurs inside a multi-status response, it
indicates only that a loop is being terminated, but does not indicates only that a loop is being terminated, but does not
indicate failure of the operation as a whole. indicate failure of the operation as a whole.
For example, consider a PROPFIND request on /Coll (bound to For example, consider a PROPFIND request on /Coll (bound to
collection C), where the members of /Coll are /Coll/Foo (bound to collection C), where the members of /Coll are /Coll/Foo (bound to
resource R) and /Coll/Bar (bound to collection C). resource R) and /Coll/Bar (bound to collection C).
>> Request: >> Request:
PROPFIND /Coll/ HTTP/1.1 PROPFIND /Coll/ HTTP/1.1
Host: www.somehost.com Host: www.example.com
Depth: infinity Depth: infinity
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:propfind xmlns:D="DAV:"> <D:propfind xmlns:D="DAV:">
<D:prop> <D:displayname/> </D:prop> <D:prop> <D:displayname/> </D:prop>
</D:propfind> </D:propfind>
>> Response: >> Response:
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Clemm, et al. [Page 14]
Content-Length: xxx Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"> <D:multistatus xmlns:D="DAV:">
<D:response> <D:response>
<D:href>http://www.somehost.com/Coll/</D:href> <D:href>http://www.example.com/Coll/</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<D:displayname>Loop Demo</D:displayname> <D:displayname>Loop Demo</D:displayname>
</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:response> <D:response>
<D:href>http://www.somehost.com/Coll/Foo</D:href> <D:href>http://www.example.com/Coll/Foo</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<D:displayname>Bird Inventory</D:displayname> <D:displayname>Bird Inventory</D:displayname>
</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:response> <D:response>
<D:href>http://www.somehost.com/Coll/Bar</D:href> <D:href>http://www.example.com/Coll/Bar</D:href>
<D:status>HTTP/1.1 506 Loop Detected</D:status> <D:status>HTTP/1.1 506 Loop Detected</D:status>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
Clemm, et al. [Page 15]
6 SECURITY CONSIDERATIONS 6 SECURITY CONSIDERATIONS
This section is provided to make WebDAV applications aware of the This section is provided to make WebDAV applications aware of the
security implications of this protocol. 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, bindings introduce several protocol specification. In addition, bindings introduce several
new security concerns and increase the risk of some existing new security concerns and increase the risk of some existing
threats. These issues are detailed below. threats. These issues are detailed below.
skipping to change at line 736 skipping to change at line 762
bindings on a trusted server may make it possible for a hostile bindings on a trusted server may make it possible for a hostile
agent to induce users to send private information to a target on a agent to induce users to send private information to a target on a
different server. different server.
6.2 Redirect Loops 6.2 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 BIND method creates a new avenue for clients to introduction of the BIND method creates a new avenue for clients to
create loops accidentally or maliciously. If the binding and its create loops accidentally or maliciously. If the binding and its
target are on the same server, the server may be able to detect target are on the same server, the server may be able to detect
Clemm, et al. [Page 15]
BIND requests that would create loops. Servers are required to BIND requests that would create loops. Servers are required to
detect loops that are caused by bindings to collections during the detect loops that are caused by bindings to collections during the
processing of any requests with "Depth: infinity". processing of any requests with "Depth: infinity".
6.3 Bindings, and Denial of Service 6.3 Bindings, and Denial of Service
Denial of service attacks were already possible by posting URLs Denial of service attacks were already possible by posting URLs
that were intended for limited use at heavily used Web sites. The that were intended for limited use at heavily used Web sites. The
introduction of BIND creates a new avenue for similar denial of introduction of BIND creates a new avenue for similar denial of
service attacks. If cross-server bindings are supported, clients service attacks. If cross-server bindings are supported, clients
skipping to change at line 760 skipping to change at line 784
6.4 Private Locations May Be Revealed 6.4 Private Locations May Be Revealed
If the DAV:parent-set property is maintained on a resource, the If the DAV:parent-set property is maintained on a resource, the
owners of the bindings risk revealing private locations. The owners of the bindings risk revealing private locations. The
directory structures where bindings are located are available to directory structures where bindings are located are available to
anyone who has access to the DAV:parent-set property on the anyone who has access to the DAV:parent-set property on the
resource. Moving a binding may reveal its new location to anyone resource. Moving a binding may reveal its new location to anyone
with access to DAV:parent-set on its resource. with access to DAV:parent-set on its resource.
Clemm, et al. [Page 16]
6.5 DAV:parent-set and Denial of Service 6.5 DAV:parent-set and Denial of Service
If the server maintains the DAV:parent-set property in response to If the server maintains the DAV:parent-set property in response to
bindings created in other administrative domains, it is exposed to bindings created in other administrative domains, it is exposed to
hostile attempts to make it devote resources to adding bindings to hostile attempts to make it devote resources to adding bindings to
the list. the list.
7 INTERNATIONALIZATION CONSIDERATIONS 7 INTERNATIONALIZATION CONSIDERATIONS
All internationalization considerations mentioned in [RFC2518] also All internationalization considerations mentioned in [RFC2518] also
skipping to change at line 786 skipping to change at line 811
9 INTELLECTUAL PROPERTY 9 INTELLECTUAL PROPERTY
The following notice is copied from RFC 2026, Section 10.4, and The following notice is copied from RFC 2026, Section 10.4, and
describes the position of the IETF concerning intellectual property describes the position of the IETF concerning intellectual property
claims made against this document. claims made against this document.
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 or other rights that might be claimed to intellectual property or other rights that might be claimed to
pertain to the implementation or use other technology described in pertain to the implementation or use other technology described in
Clemm, et al. [Page 16]
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; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on has made any effort to identify any such rights. Information on
the procedures of the IETF with respect to rights in standards- the procedures of the IETF with respect to rights in standards-
track and standards-related documentation can be found in BCP-11. track and standards-related documentation can be found in BCP-11.
Copies of claims of rights made available for publication and any Copies of claims of rights made available for publication and any
assurances of licenses to be made available, or the result of an assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use attempt made to obtain a general license or permission for the use
of such proprietary rights by implementers or users of this of such proprietary rights by implementers or users of this
specification can be obtained from the IETF Secretariat. specification can be obtained from the IETF Secretariat.
skipping to change at line 812 skipping to change at line 835
this standard. Please address the information to the IETF this standard. Please address the information to the IETF
Executive Director. Executive Director.
10 ACKNOWLEDGEMENTS 10 ACKNOWLEDGEMENTS
This draft is the collaborative product of the authors and Tyson This draft is the collaborative product of the authors and Tyson
Chihaya, Jim Davis, and Chuck Fay. This draft has benefited from Chihaya, Jim Davis, and Chuck Fay. This draft has benefited from
thoughtful discussion by Jim Amsden, Peter Carlson, Steve Carter, thoughtful discussion by Jim Amsden, Peter Carlson, Steve Carter,
Ken Coar, Ellis Cohen, Dan Connolly, Bruce Cragun, Spencer Dawkins, Ken Coar, Ellis Cohen, Dan Connolly, Bruce Cragun, Spencer Dawkins,
Mark Day, Rajiv Dulepet, David Durand, Roy Fielding, Yaron Goland, Mark Day, Rajiv Dulepet, David Durand, Roy Fielding, Yaron Goland,
Clemm, et al. [Page 17]
Fred Hitt, Alex Hopmann, James Hunt, Marcus Jager, Chris Kaler, Fred Hitt, Alex Hopmann, James Hunt, Marcus Jager, Chris Kaler,
Manoj Kasichainula, Rohit Khare, Daniel LaLiberte, Steve Martin, Manoj Kasichainula, Rohit Khare, Daniel LaLiberte, Steve Martin,
Larry Masinter, Jeff McAffer, Surendra Koduru Reddy, Max Rible, Sam Larry Masinter, Jeff McAffer, Surendra Koduru Reddy, Max Rible, Sam
Ruby, Bradley Sergeant, Nick Shelness, John Stracke, John Tigue, Ruby, Bradley Sergeant, Nick Shelness, John Stracke, John Tigue,
John Turner, Kevin Wiggen, and other members of the WebDAV working John Turner, Kevin Wiggen, and other members of the WebDAV working
group. group.
11 REFERENCES 11 REFERENCES
[RFC2026] S.Bradner, "The Internet Standards Process", RFC 2026, [RFC2026] S.Bradner, "The Internet Standards Process", RFC 2026,
skipping to change at line 841 skipping to change at line 866
Resource Identifiers (URI): Generic Syntax." RFC 2396, August 1998. Resource Identifiers (URI): Generic Syntax." RFC 2396, August 1998.
[RFC2518] Y.Goland, E.Whitehead, A.Faizi, S.R.Carter, D.Jensen, [RFC2518] Y.Goland, E.Whitehead, A.Faizi, S.R.Carter, D.Jensen,
"HTTP Extensions for Distributed Authoring - WEBDAV", RFC 2518, "HTTP Extensions for Distributed Authoring - WEBDAV", RFC 2518,
February 1999. February 1999.
[RFC2616] R.Fielding, J.Gettys, J.C.Mogul, H.Frystyk, L.Masinter, [RFC2616] R.Fielding, J.Gettys, J.C.Mogul, H.Frystyk, L.Masinter,
P.Leach, and T.Berners-Lee, "Hypertext Transfer Protocol -- P.Leach, and T.Berners-Lee, "Hypertext Transfer Protocol --
HTTP/1.1", RFC 2616, June 1999. HTTP/1.1", RFC 2616, June 1999.
Clemm, et al. [Page 17]
[XML] T. Bray, J. Paoli, C.M. Sperberg-McQueen, "Extensible Markup [XML] T. Bray, J. Paoli, C.M. Sperberg-McQueen, "Extensible Markup
Language (XML)." World Wide Web Consortium Recommendation REC-xml- Language (XML) 1.0 (Second Edition)" W3C Recommendation 6 October
19980210. http://www.w3.org/TR/1998/REC-xml-19980210. 2000. http://www.w3.org/TR/2000/REC-xml-20001006.
12 AUTHORS' ADDRESSES 12 AUTHORS' ADDRESSES
Geoffrey Clemm Geoffrey Clemm
Rational Software Corporation Rational Software Corporation
20 Maguire Road 20 Maguire Road
Lexington, MA 02173-3104 Lexington, MA 02173-3104
Email: geoffrey.clemm@rational.com Email: geoffrey.clemm@rational.com
Jason Crawford Jason Crawford
skipping to change at line 866 skipping to change at line 890
P.O. Box 704 P.O. Box 704
Yorktown Heights, NY 10598 Yorktown Heights, NY 10598
Email: ccjason@us.ibm.com Email: ccjason@us.ibm.com
Julian F. Reschke Julian F. Reschke
greenbytes GmbH greenbytes GmbH
Salzmannstrasse 152 Salzmannstrasse 152
Muenster, NW 48159, Germany Muenster, NW 48159, Germany
Email: julian.reschke@greenbytes.de Email: julian.reschke@greenbytes.de
Clemm, et al. [Page 18]
Judy Slein Judy Slein
Xerox Corporation Xerox Corporation
800 Phillips Road, 105-50C 800 Phillips Road, 105-50C
Webster, NY 14580 Webster, NY 14580
Email: jslein@crt.xerox.com Email: jslein@crt.xerox.com
Jim Whitehead Jim Whitehead
UC Santa Cruz, Dept. of Computer Science UC Santa Cruz, Dept. of Computer Science
1156 High Street, Santa Cruz, CA 95064 1156 High Street, Santa Cruz, CA 95064
Email: ejw@cse.ucsc.edu Email: ejw@cse.ucsc.edu
Clemm, et al. [Page 18] Clemm, et al. [Page 19]
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