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:
	skipping to change at line 189		skipping to change at line 191
	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.
	Clemm, et al. [Page 4]		Clemm, et al. [Page 4]
	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
	skipping to change at line 218		skipping to change at line 220
	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 collection’s 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
	skipping to change at line 261		skipping to change at line 263
	binding.		binding.
	Clemm, et al. [Page 6]		Clemm, et al. [Page 6]
	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
	skipping to change at line 306		skipping to change at line 307
	| \		| \
	+-------------+ +-------------+		+-------------+ +-------------+
	| 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
	Clemm, et al. [Page 7]
	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.
			Clemm, et al. [Page 7]
	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
	skipping to change at line 362		skipping to change at line 362
	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
	Clemm, et al. [Page 8]
	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.
			Clemm, et al. [Page 8]
	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.
	skipping to change at line 413		skipping to change at line 412
	+---------------------+ +------------------------+		+---------------------+ +------------------------+
	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.
	Clemm, et al. [Page 9]
	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
			Clemm, et al. [Page 9]
	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
	skipping to change at line 460		skipping to change at line 460
	+---------------------+		+---------------------+
	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.
			Clemm, et al. [Page 10]
	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).
	Clemm, et al. [Page 10]
	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
	skipping to change at line 512		skipping to change at line 521
	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.
			Clemm, et al. [Page 11]
	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
	Clemm, et al. [Page 11]
	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
	skipping to change at line 568		skipping to change at line 576
	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
			Clemm, et al. [Page 12]
	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.
	Clemm, et al. [Page 12]
	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]
End of changes.
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