draft-ietf-webdav-binding-protocol-01.txt   draft-ietf-webdav-binding-protocol-02.txt 
WEBDAV Working Group J. Slein, Xerox WEBDAV Working Group J. Slein, Xerox
INTERNET DRAFT E.J. Whitehead Jr., UC Irvine INTERNET DRAFT E.J. Whitehead Jr., UC Irvine
<draft-ietf-webdav-binding-protocol-01.txt> J. Davis, CourseNet <draft-ietf-webdav-binding-protocol-02.txt> J. Davis, CourseNet
G. Clemm, Rational G. Clemm, Rational
C. Fay, FileNet C. Fay, FileNet
J. Crawford, IBM J. Crawford, IBM
T. Chihaya, DataChannel December 17, 1999
October 15, 1999 Expires June 17, 2000
Expires April 15, 2000
WebDAV Bindings WebDAV Bindings
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 Section 10 of RFC2026. Internet-Drafts are working provisions of Section 10 of RFC2026. Internet-Drafts are working
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Abstract Abstract
The WebDAV Distributed Authoring Protocol provides basic support for This is one of a pair of specifications that extend the WebDAV
collections, offering the ability to create and list unordered Distributed Authoring Protocol to enable clients to create new access
collections. paths to existing resources. The two protocol extensions have very
different characteristics that make them useful for different sorts of
applications.
This specification is one of a group of three specifications that The present specification defines bindings, and the BIND method for
supplement the WebDAV Distributed Authoring Protocol to increase the creating them. Creating a new binding to a resource indirectly creates
power of WebDAV collections. This specification defines bindings, one one or more new URIs mapped to that resource, which can then be used to
mechanism for allowing a single resource to appear in more than one access it. Servers are required to insure the integrity of any bindings
collection. Bindings make this possible by creating mappings of URIs to that they allow to be created.
resources. The BIND method defined here gives clients the ability to
create new bindings to existing resources. The second specification, The related specification, RFC xxxx, defines redirect reference
"WebDAV Redirect Reference Resources"[RR], defines redirect references, resources. A redirect reference resource is a resource whose default
another approach to allowing a single resource to be accessed from response is an HTTP/1.1 302 (Found) status code, redirecting the client
multiple collections. The third specification, "WebDAV Ordered to a different resource, the target resource. A redirect reference
Collections Protocol"[OC], provides a mechanism for ordering makes it possible to access the target resource indirectly, through any
collections. URI mapped to the redirect reference resource. There are no integrity
guarantees associated with redirect reference resources.
Table of Contents Table of Contents
1 Notational Conventions.......................................2 1 Notational Conventions.......................................2
2 Introduction.................................................3 2 Introduction.................................................3
3 Terminology..................................................4 3 Terminology..................................................4
3.1 Rationale for Distinguishing Bindings from URI Mappings......7 3.1 Rationale for Distinguishing Bindings from URI Mappings......7
4 Overview of Bindings.........................................8 4 Overview of Bindings.........................................8
5 BIND Method..................................................8 5 BIND Method..................................................8
5.1 Overview of BIND.............................................8 5.1 Overview of BIND.............................................8
5.2 Bindings to Collections......................................9 5.2 Bindings to Collections......................................9
5.3 URI Mappings Created by a BIND..............................10 5.3 URI Mappings Created by a BIND..............................10
5.4 Example: URI Mappings Created by a BIND.....................10 5.4 Example: URI Mappings Created by a BIND.....................11
5.5 BIND Status Codes...........................................11 5.5 BIND Status Codes...........................................11
5.6 Example: BIND...............................................11 5.6 Example: BIND...............................................11
6 DELETE and Bindings.........................................11 6 DELETE and Bindings.........................................12
7 COPY and Bindings...........................................12 7 COPY and Bindings...........................................12
8 MOVE and Bindings...........................................13 8 MOVE and Bindings...........................................13
8.1 Implementation Note.........................................14 9 Bindings and Other Methods..................................14
8.2 MOVE and Locks..............................................15 10 Determining Whether Two Bindings Are to the Same Resource...14
9 LOCK and UNLOCK.............................................16 10.1 resourceid URI Scheme.......................................15
10 Bindings and Other Methods..................................17 11 Discovering the Bindings to a Resource......................15
11 Determining Whether Two Bindings Are to the Same 12 Status Codes................................................16
Resource....................................................17 12.1 506 Loop Detected...........................................16
11.1 davresourceid URI Scheme....................................17 12.2 507 Cross-Server Binding Forbidden..........................17
12 Discovering the Bindings to a Resource......................18 13 Properties..................................................17
13 Status Codes................................................18 13.1 bindings Property...........................................17
13.1 506 Loop Detected...........................................18 13.2 resourceid Property.........................................18
13.2 507 Loop Forbidden..........................................20 14 XML Elements................................................18
13.3 508 Cross-Server Binding Forbidden..........................20 14.1 segment XML Element.........................................18
14 Headers.....................................................20 15 Capability Discovery........................................18
14.1 All-Bindings Request Header.................................20 15.1 Example: Discovery of Support for Bindings..................18
14.2 Loop Header.................................................20 16 Security Considerations.....................................19
15 Properties..................................................20 16.1 Privacy Concerns............................................19
15.1 bindings Property...........................................20 16.2 Redirect Loops..............................................19
15.2 guid Property...............................................21 16.3 Bindings, and Denial of Service.............................19
16 XML Elements................................................21 16.4 Private Locations May Be Revealed...........................20
16.1 segment XML Element.........................................21 16.5 DAV:bindings and Denial of Service..........................20
17 Capability Discovery........................................21 17 Internationalization Considerations.........................20
17.1 Example: Discovery of Support for Bindings..................21 18 IANA Considerations.........................................20
18 Security Considerations.....................................22 19 Copyright...................................................21
18.1 Privacy Concerns............................................22 20 Intellectual Property.......................................21
18.2 Redirect Loops..............................................22 21 Acknowledgements............................................21
18.3 Bindings, and Denial of Service.............................22 22 References..................................................21
18.4 Private Locations May Be Revealed...........................22 23 Authors' Addresses..........................................22
18.5 DAV:bindings and Denial of Service..........................23 24 Appendices..................................................22
19 Internationalization Considerations.........................23 24.1 Appendix 1: Extensions to the WebDAV Document Type
20 IANA Considerations.........................................23 Definition..................................................22
21 Copyright...................................................23
22 Intellectual Property.......................................23
23 Acknowledgements............................................24
24 References..................................................24
25 Authors' Addresses..........................................24
26 Appendices..................................................25
26.1 Appendix 1: Extensions to the WebDAV Document Type
Definition..................................................25
1 Notational Conventions 1 Notational Conventions
Since this document describes a set of extensions to the WebDAV Since this document describes a set of extensions to the WebDAV
Distributed Authoring Protocol [WebDAV], itself an extension to the Distributed Authoring Protocol [WebDAV], itself an extension to the
HTTP/1.1 protocol, the augmented BNF used here to describe protocol HTTP/1.1 protocol, the augmented BNF used here to describe protocol
elements is exactly the same as described in Section 2.1 of [HTTP]. elements is exactly the same as described in Section 2.1 of [HTTP].
Since this augmented BNF uses the basic production rules provided in Since this augmented BNF uses the basic production rules provided in
Section 2.2 of [HTTP], these rules apply to this document as well. Section 2.2 of [HTTP], these rules apply to this document as well.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2 Introduction 2 Introduction
The simple collections that the WebDAV Distributed Authoring Protocol This is one of a pair of specifications that extend the WebDAV
supports are powerful enough to be widely useful. They provide for the Distributed Authoring Protocol to enable clients to create new access
hierarchical organization of resources, with mechanisms for creating and paths to existing resources. This capability is useful for several
deleting collections, copying and moving them, locking them, adding reasons:
members to them and removing members from them, and getting listings of
their members. Delete, copy, move, list, and lock operations can be
applied recursively, so that a client can operate on whole hierarchies
with a single request.
This specification is one of a family of three specifications that build
on the infrastructure defined in [HTTP] and [WebDAV] to extend the
capabilities of collections. The companion specification, "WebDAV
Ordered Collections Protocol"[OC], defines protocol extensions to
support ordered collections. The present specification and the
companion specification, "WebDAV Redirect Reference Resources"[RR],
define mechanisms for allowing the same resource to appear in multiple
collections. This capability is useful for several reasons:
Organizing resources into hierarchies places them into smaller URIs of WebDAV-compliant resources are hierarchical and correspond to a
groupings, known as collections, which are more easily browsed and hierarchy of collections in resource space. The WebDAV Distributed
manipulated than a flat namespace. However, hierarchies require Authoring Protocol makes it possible to organize these resources into
categorization decisions that locate resources at a single location in hierarchies, placing them into groupings, known as collections, which
the hierarchy, a drawback when a resource has multiple valid categories. are more easily browsed and manipulated than a single flat collection.
For example, in a hierarchy of vehicle descriptions containing However, hierarchies require categorization decisions that locate
collections for cars and boats, a description of a combination car/boat resources at a single location in the hierarchy, a drawback when a
vehicle could belong in either collection. Ideally, the description resource has multiple valid categories. For example, in a hierarchy of
should be accessible from both. vehicle descriptions containing collections for cars and boats, a
description of a combination car/boat vehicle could belong in either
collection. Ideally, the description should be accessible from both.
Allowing clients to create new URIs that access the existing resource
lets them put that resource into multiple collections.
Hierarchies also make resource sharing more difficult, since resources Hierarchies also make resource sharing more difficult, since resources
that have utility across many collections are still forced into a single that have utility across many collections are still forced into a single
collection. For example, the mathematics department at one university collection. For example, the mathematics department at one university
might create a collection of information on fractals that contains might create a collection of information on fractals that contains
bindings to some local resources, but also provides access to some bindings to some local resources, but also provides access to some
resources at other universities. For many reasons, it may be resources at other universities. For many reasons, it may be
undesirable to make physical copies of the shared resources on the local undesirable to make physical copies of the shared resources on the local
server û to conserve disk space, to respect copyright constraints, or to server: to conserve disk space, to respect copyright constraints, or to
make any changes in the shared resources visible automatically. make any changes in the shared resources visible automatically. Being
able to create new access paths to existing resources in other
collections or even on other servers is useful for this sort of case.
The companion specification [RR] defines redirect references, one The BIND method defined here provides a mechanism for allowing clients
mechanism for providing access to a single resource from multiple to create alternative access paths to existing WebDAV resources. HTTP
collections. A redirect reference is a resource in one collection whose and WebDAV methods are able to work because there are mappings between
URIs and resources. A method is addressed to a URI, and the server
follows the mapping from that URI to a resource, applying the method to
that resource. Multiple URIs may be mapped to the same resource, but
until now there has been no way for clients to create additional URIs
mapped to existing resources.
purpose is to forward requests to another resource (its target), usually BIND lets clients associate a new URI with an existing WebDAV resource,
in a different collection. In this way, it provides access to the and this URI can then be used to submit requests to the resource. Since
target resource from another collection. It redirects most requests to URIs of WebDAV resources are hierarchical, and correspond to a hierarchy
the target resource using the HTTP 302 (Moved Temporarily) status code, of collections in resource space, the BIND method also has the effect of
thereby providing a form of mediated access to the target resource. adding the resource to a collection. As new URIs are associated with
the resource, it appears in additional collections.
The BIND method defined here provides a different mechanism for allowing The companion specification, RFC xxxx, defines redirect reference
a single resource to appear in multiple collections. BIND lets clients resources, a different mechanism for creating alternative access paths
associate a new URI with an existing resource, and this URI can then be to existing resources. A redirect reference is a resource in one
used to submit requests to the resource. Since URIs in WebDAV are collection whose purpose is to forward requests to another resource (its
hierarchical, and correspond to a hierarchy of collections in resource target), usually in a different collection. In this way, it provides
space, the BIND method also has the effect of adding the resource to a access to the target resource from another collection. It redirects
collection. As new URIs are associated with the resource, it appears in most requests to the target resource using the HTTP 302 (Moved
additional collections. Temporarily) status code, thereby providing a form of mediated access to
the target resource.
These two approaches to allowing clients to add a single resource to Bindings and redirect reference resources have very different
multiple collections have very different characteristics: characteristics:
A BIND request does not create a new resource, but simply makes
available a new URI for submitting requests to an existing resource.
The new URI is indistinguishable from any other URI when submitting a
request to a resource. Only one round trip is needed to submit a
request to the intended target. Servers are required to enforce the
integrity of the relationships between the new URIs and the resources
associated with them. Consequently, it may be very costly for servers
to support BIND requests that cross server boundaries.
A redirect reference is a resource, and so can have properties of its A redirect reference is a resource, and so can have properties of its
own. Such information as who created the reference, when, and why can own. Properties of the redirect reference can contain such information
be stored on the redirect reference resource. Since redirect references as who created the reference, when, and why. Since redirect references
are implemented using HTTP 302 responses, it generally takes two round are implemented using HTTP 302 responses, it generally takes two round
trips to submit a request to the intended resource. Servers are not trips to submit a request to the intended resource. Servers are not
required to enforce the integrity of redirect references. Redirect required to enforce the integrity of redirect references. Redirect
references work equally well for local resources and for resources that references work equally well for local resources and for resources that
reside on a different server from the reference. reside on a different server from the reference.
By contrast, a BIND request does not create a new resource, but simply
makes available a new URI for submitting requests to an existing
resource. The new URI can be used like any other URI when submitting a
request to a resource. Only one round trip is needed to submit a
request to the intended target. Servers are required to enforce the
integrity of the relationships between the new URIs clients create and
the resources associated with them. Consequently, it is unlikely that
servers will support BIND requests that cross server boundaries.
The remainder of this specification is organized as follows. Section 3 The remainder of this specification is organized as follows. Section 3
defines terminology used in the rest of the specification, while Section defines terminology used in the rest of the specification, while Section
4 briefly overviews bindings. Section 5 specified the BIND method, used 4 briefly overviews bindings. Section 5 specifies the BIND method, used
to create bindings. Sections 6 through 10 discuss the relationships to create bindings. Sections 6 through 9 discuss the relationships
between bindings and other HTTP and WebDAV methods. Sections 11 and 12 between bindings and other HTTP and WebDAV methods. Sections 10 and 11
define mechanisms for tracking bindings. Sections 13 through 16 define define mechanisms for tracking bindings. Sections 12 through 14 define
the new status codes, headers, properties, and XML elements needed to the new status codes, properties, and XML elements needed to support
support bindings. Section 17 discusses compliance and capability bindings. Section 15 discusses compliance and capability discovery.
discovery. Security concerns, internationalization issues, and IANA Security concerns, internationalization issues, and IANA considerations
considerations are described in Sections 18 through 20. The remaining are described in Sections 16 through 18. The remaining sections provide
sections provide other supporting information. other supporting information.
3 Terminology 3 Terminology
The terminology used here follows and extends that in the WebDAV The terminology used here follows and extends that in the WebDAV
Distributed Authoring Protocol specification [WebDAV]. Definitions of Distributed Authoring Protocol specification [WebDAV]. Definitions of
the terms resource, Uniform Resource Identifier (URI), and Uniform the terms resource, Uniform Resource Identifier (URI), and Uniform
Resource Locator (URL) are provided in [URI]. Resource Locator (URL) are provided in [URI].
URI Mapping URI Mapping
A relation between an absolute URI and a resource. For an A relation between an absolute URI and a resource. For an
skipping to change at line 249 skipping to change at line 241
Formally, as defined in section 3.3 of [URI]. Formally, as defined in section 3.3 of [URI].
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. segment and the same resource, these are two distinct bindings.
So for a collection C, a path segment S, and a resource R, the So 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 binding can be thought of as C:(S -> R). Bindings create URI
mappings, and hence allow requests to be sent to a single resource mappings, and hence allow requests to be sent to a single resource
from multiple locations in a URI namespace. from multiple locations in a URI namespace. For example, given
The following figure can be used to illustrate how bindings create o collection C, accessible through the URI
URI mappings. http://www.srv.com/coll/,
o path segment S, equal to "foo.html", and
o resource R,
creating the binding C: (S -> R) makes it possible to use the URI
http://www.srv.com/coll/foo.html to access R.
The following figure illustrates a more complex example of how
bindings create URI mappings.
+-----------------------------+ +-----------------------------+
| root collection | | root collection |
|-----------------------------| |-----------------------------|
| bindings: | | bindings: |
| | | |
| Coll1 Coll2 Coll3 | | Coll1 Coll2 Coll3 |
| | | \ | | | | \ |
+---|-------|--------\--------+ +---|-------|--------\--------+
| | \ | | \
skipping to change at line 280 skipping to change at line 280
| | \ | | / | | | \ | | / |
+--|------\---------+ +-/--------------------+ +--|------\---------+ +-/--------------------+
| \ / | \ /
| \ / | \ /
| \ / | \ /
| \ / | \ /
+--------------+ +---------------+ +--------------+ +---------------+
| resource R1 | | resource R2 | | resource R1 | | resource R2 |
+--------------+ +---------------+ +--------------+ +---------------+
Figure 2 Figure 1
Since there are two bindings in the root collection, Coll1 and Since there are two bindings in the root collection, Coll1 and
Coll2, to collection C1, the single binding C1:(foo -> R1) between Coll2, to collection C1, the single binding C1:(foo -> R1) between
foo and resource R1 in collection C1 creates two URI mappings, foo and resource R1 in collection C1 creates two URI mappings,
/Coll1/foo and /Coll2/foo, to resource R1. Each of these URI /Coll1/foo and /Coll2/foo, to resource R1. Each of these URI
mappings can be used to submit requests to R1. The binding mappings can be used to submit requests to R1. The binding
C1:(bar -> R2) between bar and resource R2 in collection C1 and C1:(bar -> R2) between bar and resource R2 in collection C1 and
the binding C2:(foo -> R2) between foo and resource R2 in the binding C2:(foo -> R2) between foo and resource R2 in
collection C2 create altogether 3 URI mappings to resource R2: collection C2 create altogether 3 URI mappings to resource R2:
/Coll1/bar, /Coll2/bar, and /Coll3/foo. All 3 URI mappings can be /Coll1/bar, /Coll2/bar, and /Coll3/foo. All 3 URI mappings can be
used to submit requests to resource R2. used to submit requests to resource R2.
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 member resources. that identify member resources.
Internal Member URI Internal Member URI
Informally, the complete set of URLs by which a collectionÆs Informally, the complete set of URLs by which a collection member
member is known. Formally, the URI element U of a URI mapping is known. Formally, the URI U of a URI mapping (U => R), created
(U => R), created by a binding that is contained in a collection. by a binding that is contained in a collection. The following
The following figure illustrates the relationship between bindings figure illustrates the relationship between bindings and internal
and internal member URIs in a collection: member URIs in a collection:
+-----------------------------+ +-----------------------------+
| root collection | | root collection |
|-----------------------------| |-----------------------------|
| internal member URIs: | | internal member URIs: |
| | | |
| /Coll1/ | | /Coll1/ |
| /Coll2/ | | /Coll2/ |
| /Coll3/ | | /Coll3/ |
|-----------------------------| |-----------------------------|
skipping to change at line 342 skipping to change at line 343
| | \ | / | | \ | /
+--|------\------------+ / +--|------\------------+ /
| \ / | \ /
| \ / | \ /
| \ / | \ /
| \ / | \ /
+--------------+ +---------------+ +--------------+ +---------------+
| resource R1 | | resource R2 | | resource R1 | | resource R2 |
+--------------+ +---------------+ +--------------+ +---------------+
Figure 3 Figure 2
The URI elements of all URI mappings created by a collection's The URIs of all URI mappings created by a collection's bindings
bindings are internal member URIs of the collection. are internal member URIs of the collection.
However, for a given request, only the URIs from those URI However, for a given request, only the URIs from those URI
mappings that incorporate the Request-URI are treated as internal mappings that incorporate the Request-URI are treated as internal
member URIs. For example, in Figure 3 above, if a PROPFIND member URIs. This is done to prevent large amounts of duplicate
request with "Depth: infinity" is submitted to collection C1 using information from being returned for operations on collections.
the Request-URI /Coll1/, only the URI mappings starting with the The problem would occur if a PROPFIND on a collection to which
Request-URI would be listed as internal member URIs. The response there are multiple URI mappings returned information for every URI
would include only /Coll1/ itself and the internal member URIs mapping.
/Coll1/foo and /Coll1/bar. This is done to prevent large amounts
of duplicate information from being returned for operations on For example, in Figure 2 above, if a PROPFIND request with "Depth:
collections. infinity" is submitted to collection C1 using the Request-URI
/Coll1/, only the URI mappings starting with the Request-URI would
be listed as internal member URIs. The response would include
only /Coll1/ itself and the internal member URIs /Coll1/foo and
/Coll1/bar. It would not include /Coll2/, /Coll2/foo, or
/Coll2/bar, even though the URI /Coll2/ does map to the
collection, and /Coll2/foo and /Coll2/bar are internal member URIs
of the collection.
In [WebDAV], a collection is defined as containing a list of In [WebDAV], a collection is defined as containing a list of
internal member URIs, where an internal member URI is the URI of internal member URIs, where an internal member URI is the URI of
the collection, plus a single path segment. This definition the collection, plus a single path segment. This definition
combines the two concepts of binding and URI mapping that are combines the two concepts of binding and URI mapping that are
separated in this specification. As a result, this specification separated in this specification. As a result, this specification
redefines a collection's state to be a set of bindings, and redefines a collection's state to be a set of bindings, and
redefines an internal member URI to be the URI of a URI mapping redefines an internal member URI to be the URI of a URI mapping
derived from a binding. After this redefinition, an internal derived from a binding. After this redefinition, an internal
member URI can be used when reading [WebDAV] without loss of member URI can be used when reading [WebDAV] without loss of
meaning. For purposes of interpretation, when [WebDAV] discusses a meaning. For purposes of interpretation, when [WebDAV] discusses a
collection "containing" an internal member URI, this should be collection "containing" an internal member URI, this should be
read as the collection containing a binding whose mapping to a URI read as the collection containing a binding whose mapping to a URI
creates an internal member URI, in this sense "containing" the creates an internal member URI, in this sense "containing" the
internal member URI. The authors of this specification anticipate internal member URI. The authors of this specification anticipate
and recommend that future revisions of [WebDAV] perform a full and recommend that future revisions of [WebDAV] perform a full
reconciliation of terms between these two specifications. reconciliation of terms between these two specifications.
3.1 Rationale for Distinguishing Bindings from URI Mappings 3.1 Rationale for Distinguishing Bindings from URI Mappings
Consider again collection C1 in Figure 3. If we had only the notion of Consider again collection C1 in Figure 2. If we had only the notion of
URI mappings, we would be forced to say that C1's membership was defined URI mappings, we would be forced to say that C1's membership was defined
by the list of internal member URIs. If these URIs identify the by the list of internal member URIs. If these URIs identify the
membership, and are part of the state of the collection, then the act of membership, and are part of the state of the collection, then the act of
making the collection available via a new URI has the effect of changing making the collection available via a new URI has the effect of changing
the collectionÆs membership, hence changing the collectionÆs state. This the collection's membership, hence changing the collection's state. This
is undesirable, since ideally a collectionÆs membership should remain is undesirable, since ideally a collection's membership should remain
the same, no matter what URIs can be used to access the collection. What the same, if suddenly a new URI can be used to access the collection.
is needed is a way to separate the final segment of a URI from the What is needed is a way to separate the final segment of a URI from the
collectionÆs URI contribution. collection's URI contribution.
The notion of binding is introduced to separate the final segment of a The notion of binding is introduced to separate the final segment of a
URI from its parent collectionÆs contribution. This done, a collection URI from its parent collectionÆs contribution. This done, a collection
can be defined as containing a set of bindings, thus permitting a new can be defined as containing a set of bindings, thus permitting new
mappings to a collection without modifying its membership. We introduce
mapping to be defined to a collection without modifying its membership the concept of URI mapping to combine together the collection's URI and
state. We introduce the concept of URI mapping to combine together the a binding's segment to create a full URI that can be used in protocol
collectionÆs URI and a bindingÆs segment to create a full URI that can requests. Finally, the internal member URI, first defined in [WebDAV],
be used in protocol requests. Finally, the internal member URI, first is redefined here to maintain backward compatibility with that
defined in [WebDAV], is redefined here to maintain backward specification.
compatibility with that specification.
4 Overview of Bindings 4 Overview of Bindings
Bindings are part of the state of a collection. In general, there is a Bindings are part of the state of a collection. In general, there is a
one-to-many correspondence between a collection's bindings and its one-to-many correspondence between a collection's bindings and its
internal member URIs, as illustrated in Figure 3 above. The URI segment internal member URIs, as illustrated in Figure 2 above. The URI segment
associated with a resource by one of a collection's bindings is also the associated with a resource by one of a collection's bindings is also the
final segment of one or more of the collection's internal member URIs. final segment of one or more of the collection's internal member URIs.
The final segment of each internal member URI identifies one of the The final segment of each internal member URI identifies one of the
bindings that is part of the collection's state. bindings that is part of the collection's state.
Bindings are not unique to advanced collections, although the BIND Bindings are not unique to advanced collections, although the BIND
method for explicitly creating bindings is introduced here. Existing method for explicitly creating bindings is introduced here. Existing
methods that create resources, such as PUT, MOVE, COPY, and MKCOL, methods that create resources, such as PUT, MOVE, COPY, and MKCOL,
implicitly create bindings. There is no difference between implicitly implicitly create bindings. There is no difference between implicitly
created bindings and bindings created with BIND. created bindings and bindings created with BIND.
The identity of a binding C:(S -> R) is determined by the URI segment The identity of a binding C:(S -> R) is determined by the URI segment
(in its collection) and the resource that the binding associates. If (in its collection) and the resource that the binding associates. If
the resource goes out of existence (as a result of some out-of-band the resource goes out of existence (as a result of some out-of-band
operation), the binding also goes out of existence. If the URI segment operation), the binding also goes out of existence. If the URI segment
comes to be associated with a different resource, the original binding comes to be associated with a different resource, the original binding
ceases to exist and another binding is created. ceases to exist and another binding is created.
Since a binding is a relation between a path segment in a collection and It would be very undesirable if one binding could be destroyed as a side
a resource, it would be very undesirable if one binding could be effect of operating on the resource through a different binding. It is
destroyed as a side effect of operating on the resource through a not acceptable for moving a resource through one binding to disrupt
different binding. It is not acceptable for a MOVE through one binding another binding, turning that binding into a dangling path segment. Nor
to disrupt another binding, turning that binding into a dangling path is it acceptable for a server, after removing one binding, to reclaim
segment. Nor is it acceptable for a server, after performing a DELETE the system resources associated with its resource while other bindings
through one binding, to reclaim the system resources associated with its to the resource remain. Implementations MUST ensure the integrity of
resource while other bindings to the resource remain. Implementations bindings.
MUST ensure the integrity of bindings.
5 BIND Method 5 BIND Method
5.1 Overview of BIND 5.1 Overview of BIND
The BIND method creates a new binding between the resource identified by The BIND method creates a new binding between the resource identified by
the Request-URI and the final segment of the Destination header (minus the Request-URI and the final segment of the Destination header (minus
any trailing slash). This binding is added to the collection identified any trailing slash). This binding is added to the collection identified
by the Destination header minus its trailing slash (if present) and by the Destination header minus its trailing slash (if present) and
final segment. The Destination header is defined in Section 9.3 of final segment. The Destination header is defined in Section 9.3 of
[WebDAV]. [WebDAV].
If a server cannot guarantee the binding behavior specified here, If a server cannot guarantee the binding behavior specified here,
including the guarantee of the integrity of the binding, the BIND including the guarantee of the integrity of the binding, the BIND
request MUST fail. request MUST fail.
skipping to change at line 457 skipping to change at line 465
Note: It is especially difficult to maintain the integrity of cross- Note: It is especially difficult to maintain the integrity of cross-
server bindings. Unless the server where the resource resides knows server bindings. Unless the server where the resource resides knows
about all bindings on all servers to that resource, it may unwittingly about all bindings on all servers to that resource, it may unwittingly
destroy the resource or move it without notifying another server that destroy the resource or move it without notifying another server that
manages a binding to the resource. For example, if server A permits manages a binding to the resource. For example, if server A permits
creation of a binding to a resource on server B, server A must notify creation 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 server B about its binding and must have an agreement with B that B will
not destroy the resource while A's binding exists. Otherwise server B not destroy the resource while A's binding exists. Otherwise server B
may receive a DELETE request that it thinks removes the last binding to may receive a DELETE request that it thinks removes the last binding to
the resource and destroy the resource while A's binding still exists. the resource and destroy the resource while A's binding still exists.
Since most servers will be forced to fail cross-server BIND requests Status code 507 (Cross-server Binding Forbidden) is defined in Section
because they are unable to guarantee the integrity of cross-server 12.2 for cases where servers must fail cross-server BIND requests
bindings, status code 508 (Cross-server Binding Forbidden) is defined in because they cannot guarantee the integrity of cross-server bindings.
Section 13.3.
If the Destination header does not contain a path segment (i.e., it If the Destination header does not contain a path segment (i.e., it
consists simply of a slash "/"), the BIND operation MUST fail and report consists simply of a slash "/"), the BIND operation MUST fail and report
a 400 (Bad Request) status code. A binding consists of a (collection, a 400 (Bad Request) status code. A binding consists of a (collection,
segment, resource) triple, and the Destination header is required to segment, resource) triple, and the Destination header is required to
specify the collection and segment of this triple. specify the collection and segment of this triple.
If the Destination header minus its final path segment does not identify
a collection, the BIND operation MUST fail and report a 400 (Bad
Request) status code.
Note: Section 5.1 of [WebDAV] defines a consistent namespace to be one
such that "for every URL in the HTTP hierarchy there exists a collection
that contains that URL as an internal member," but [WebDAV] does not
require namespaces to be consistent. There can exist URIs that map to
resources, but do not depend on the existence of collections for the
mapping. For example, the URI http://www.svr.com/x/y.html may map to
resource R even if the URI http://www.svr.com/x/ does not map to any
resource. This specification does not support the creation of such URI
mappings. The BIND method can be used only in consistent sections of a
namespace.
After successful processing of a BIND request, it MUST be possible for After successful processing of a BIND request, it MUST be possible for
clients to use the URI in the Destination header to submit requests to clients to use the URI in the Destination header to submit requests to
the resource identified by the Request-URI. the resource identified by the Request-URI.
By default, if the Destination header identifies an existing binding, By default, if the Destination header identifies an existing binding,
the new binding replaces the existing binding. This default binding the new binding replaces the existing binding. This default binding
replacement behavior can be overridden using the Overwrite header replacement behavior can be overridden using the Overwrite header
defined in Section 9.6 of [WebDAV]. defined in Section 9.6 of [WebDAV].
5.2 Bindings to Collections 5.2 Bindings to Collections
BIND can create a binding to a collection resource. A collection Bindings to collections can result in loops. If a server wants to
accessed through such a binding behaves exactly as would a collection prevent a loop from being created, it MAY fail the BIND request with a
accessed through any other binding. 403 (Forbidden) status code. If a server allows a loop to be created,
it MUST detect the loop when processing "Depth: infinity" requests that
Bindings to collections can result in loops, which servers MUST detect encounter the loop. It is sometimes possible to complete an operation
when processing "Depth: infinity" requests. It is sometimes possible to in spite of the presence of a loop. However, the 506 (Loop Detected)
complete an operation in spite of the presence of a loop. However, the status code is defined in Section 12.1 for use in contexts where an
506 (Loop Detected) status code is defined in Section 13.1 for use in operation is terminated because a loop was encountered.
contexts where an operation is terminated because a loop was
encountered. Some servers may wish to prevent loops from being created
at all. These servers MAY fail BIND requests with the 507 (Loop
Forbidden) status code defined in Section 13.2.
Creating a new binding to a collection makes each resource associated Creating a new binding to a collection makes each resource associated
with a binding in that collection accessible via a new URI, and thus with a binding in that collection accessible via a new URI, and thus
creates new URI mappings to those resources but no new bindings. creates new URI mappings to those resources but no new bindings.
For example, suppose a new binding COLLX is created for collection C1 in For example, suppose a new binding COLLX is created for collection C1 in
the figure below. It immediately becomes possible to access resource R1 the figure below. It immediately becomes possible to access resource R1
using the URI /COLLX/x.gif and to access resource R2 using the URI using the URI /COLLX/x.gif and to access resource R2 using the URI
/COLLX/y.jpg, but no new bindings for these child resources were /COLLX/y.jpg, but no new bindings for these child resources were
created. This is because bindings are part of the state of a created. This is because bindings are part of the state of a
skipping to change at line 529 skipping to change at line 546
| bindings: | | bindings: |
| x.gif y.jpg | | x.gif y.jpg |
+------------------+ +------------------+
| \ | \
| \ | \
| \ | \
+-------------+ +-------------+ +-------------+ +-------------+
| Resource R1 | | Resource R2 | | Resource R1 | | Resource R2 |
+-------------+ +-------------+ +-------------+ +-------------+
Figure 6 Figure 3
5.3 URI Mappings Created by a BIND 5.3 URI Mappings Created by a BIND
Suppose a BIND request causes a binding from "Binding-Name" to resource Suppose a BIND request causes 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 R to be added to 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" that were mapped to C before the BIND request, then for each URI "C-URI"
in C-MAP, the URI "C-URI/Binding-Name" is mapped to resource R following in C-MAP, the URI "C-URI/Binding-Name" is mapped to resource R following
the BIND request. the BIND request.
Note that if R is a collection, additional URI mappings are created to 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 collection 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 of mappings is C to C itself (or to a parent of C), an infinite number of mappings is
introduced. introduced.
5.4 Example: URI Mappings Created by a BIND 5.4 Example: URI Mappings Created by a BIND
For example, if a binding from "foo.html" to R is added to the For example, if a binding from "foo.html" to R is added to a collection
collection C, and if the following URI's are mapped to C: C, and if the following URI's are mapped to C:
http://www.fuzz.com/A/1 http://www.fuzz.com/A/1
http://fuzz.com/A/one http://fuzz.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.fuzz.com/A/1/foo.html
http://fuzz.com/A/one/foo.html http://fuzz.com/A/one/foo.html
If a binding from "myself" to C is then added to C, the following If a binding from "myself" to C is then added to C, the following
skipping to change at line 579 skipping to change at line 595
http://www.fuzz.com/A/1/myself/myself/foo.html http://www.fuzz.com/A/1/myself/myself/foo.html
... ...
5.5 BIND Status Codes 5.5 BIND Status Codes
201 (Created): The binding was successfully created. 201 (Created): The binding was successfully created.
400 (Bad Request): The client set an invalid value for the Destination 400 (Bad Request): The client set an invalid value for the Destination
header or Request-URI. header or Request-URI.
403 (Forbidden): This server has a policy that forbids creation of
bindings that would result in loops.
412 (Precondition Failed): The Overwrite header is "F", and a binding 412 (Precondition Failed): The Overwrite header is "F", and a binding
already exists for the Destination header. already exists for the Destination header.
507 (Loop Forbidden): The server does not support bindings that create 507 (Cross-Server Binding Forbidden): The server is unable to create the
loops.
508 (Cross-Server Binding Forbidden): The server is unable to create the
requested binding because it would bind a segment in a collection on one requested binding because it would bind a segment in a collection on one
server to a resource on a different server. server to a resource on a different server.
5.6 Example: BIND 5.6 Example: BIND
>> Request: >> Request:
BIND /pub/i-d/draft-webdav-protocol-08.txt HTTP/1.1 BIND /pub/i-d/draft-webdav-protocol-08.txt HTTP/1.1
Host: www.ics.uci.edu Host: www.ics.uci.edu
Destination: http://www.ics.uci.edu/~whitehead/dav/spec08.txt Destination: http://www.ics.uci.edu/~whitehead/dav/spec08.txt
>> Response: >> Response:
HTTP/1.1 201 Created HTTP/1.1 201 Created
The server created a new binding, associating "spec08.txt" with the The server created a new binding, associating "spec08.txt" with the
resource identified by the URL "http://www.ics.uci.edu/pub/i-d/draft- resource identified by the URL "http://www.ics.uci.edu/pub/i-d/draft-
webdav-protocol-08.txt". Clients can now use the URI in the Destination webdav-protocol-08.txt". Clients can now use the URI in the Destination
skipping to change at line 614 skipping to change at line 631
header, "http://www.ics.uci.edu/~whitehead/dav/spec08.txt", to submit header, "http://www.ics.uci.edu/~whitehead/dav/spec08.txt", to submit
requests to that resource. As part of this operation, the server added requests to that resource. As part of this operation, the server added
the binding "spec08.txt" to collection /~whitehead/dav/. the binding "spec08.txt" to collection /~whitehead/dav/.
6 DELETE and Bindings 6 DELETE and Bindings
The DELETE method was originally defined in [HTTP]. This section The DELETE method was originally defined in [HTTP]. This section
redefines the behavior of DELETE in terms of bindings, an abstraction redefines the behavior of DELETE in terms of bindings, an abstraction
not available when writing [HTTP]. [HTTP] states that "the DELETE method not available when writing [HTTP]. [HTTP] states that "the DELETE method
requests that the origin server delete the resource identified by the requests that the origin server delete the resource identified by the
Request-URI." Because [HTTP] did not distinguish between bindings and Request-URI." Because [HTTP] did not distinguish between bindings and
resources, the intent of its definition of DELETE is unclear. The resources, the intent of its definition of DELETE is unclear. The
definition presented here is a clarification of the definition in definition presented here is a clarification of the definition in
[HTTP]. [HTTP].
The DELETE method requests that the server remove the binding between The DELETE method requests that the server remove the binding between
the resource identified by the Request-URI and the binding name, the the resource identified by the Request-URI and the binding name, the
last path segment of the Request-URI. The binding MUST be removed from last path segment of the Request-URI. The binding MUST be removed from
its parent collection, identified by the Request-URI minus its trailing its parent collection, identified by the Request-URI minus its trailing
slash (if present) and final segment. The All-Bindings header may be slash (if present) and final segment.
used with DELETE to request that the server remove all bindings to the
resource identified by the Request-URI.
Once a set of resources are unreachable by any URI mapping, the server Once a resource is unreachable by any URI mapping, the server MAY
MAY reclaim system resources associated with those resources. If DELETE reclaim system resources associated with that resource. If DELETE
removes a binding to a resource, but there remain URI mappings to that removes a binding to a resource, but there remain URI mappings to that
resource, the server MUST NOT reclaim system resources associated with resource, the server MUST NOT reclaim system resources associated with
the resource. the resource.
Although [WebDAV] allows a DELETE to be a non-atomic operation, the Although [WebDAV] allows a DELETE to be a non-atomic operation, the
DELETE operation defined here is atomic. In particular, a DELETE with DELETE operation defined here is atomic. In particular, a DELETE on a
an All-Bindings header MUST fail if any of the bindings to the resource hierarchy of resources is simply the removal of a binding to the
cannot be deleted. In addition, a DELETE on a hierarchy of resources is collection identified by the Request-URI, and so is a single (and
simply the removal of a binding to the collection identified by the therefore atomic) operation.
Request-URI, and so is a single (and therefore atomic) operation.
Section 8.6.1 of [WebDAV] states that during DELETE processing, a server Section 8.6.1 of [WebDAV] states that during DELETE processing, a server
"MUST remove any URI for the resource identified by the Request-URI from "MUST remove any URI for the resource identified by the Request-URI from
collections which contain it as a member." Servers that support collections which contain it as a member." Servers that support
bindings SHOULD NOT follow this requirement unless the All-Bindings bindings MUST NOT follow this requirement.
header is included in the request.
7 COPY and Bindings 7 COPY and Bindings
As defined in Section 8.8 of [WebDAV], COPY causes the resource As defined in Section 8.8 of [WebDAV], COPY causes the resource
identified by the Request-URI to be duplicated, and makes the new identified by the Request-URI to be duplicated, and makes the new
resource accessible using the URI specified in the Destination header. resource accessible using the URI specified in the Destination header.
Upon successful completion of a COPY, a new binding is created between Upon successful completion of a COPY, a new binding is created between
the last path segment of the Destination header, and the destination the last path segment of the Destination header, and the destination
resource. The new binding is added to its parent collection, identified resource. The new binding is added to its parent collection, identified
by the Destination header minus its trailing slash (if present) and by the Destination header minus its trailing slash (if present) and
final segment. final segment.
As an example, suppose that a COPY is issued to URI 3 for resource R Figure 4 below shows an example: Suppose that a COPY is issued to URI 3
below (which is also mapped to URI 1 and URI 2), with the Destination for resource R (which is also mapped to URI 1 and URI 2), with the
header set to URIX. After successful completion of the COPY operation, Destination header set to URIX. After successful completion of the COPY
resource R is duplicated to create resource R', and a new binding has operation, resource R is duplicated to create resource R', and a new
been created which creates at least the URI mapping between URIX and the binding has been created which creates at least the URI mapping between
new resource (although other URI mappings may also have been created). URIX and the new resource (although other URI mappings may also have
been created).
URI 1 URI 2 URI 3 URIX URI 1 URI 2 URI 3 URIX
| | | | | | | |
| | | <---- URI Mappings ----> | | | | <---- URI Mappings ----> |
| | | | | | | |
+---------------------+ +------------------------+ +---------------------+ +------------------------+
| Resource R | | Resource R' | | Resource R | | Resource R' |
+---------------------+ +------------------------+ +---------------------+ +------------------------+
Figure 7 Figure 4
It might be thought that a COPY request with "Depth: 0" on a collection It might be thought that a COPY request with "Depth: 0" on a collection
would duplicate its bindings, since bindings are part of the would duplicate its bindings, since bindings are part of the
collection's state. This is not the case, however. The definition of collection's state. This is not the case, however. The definition of
Depth in [WebDAV] makes it clear that a "Depth: 0" request does not Depth in [WebDAV] makes it clear that a "Depth: 0" request does not
apply to a collection's members. Consequently, a COPY with "Depth: 0" apply to a collection's members. Consequently, a COPY with "Depth: 0"
does not duplicate the bindings contained by the collection. does not duplicate the bindings contained by the collection.
8 MOVE and Bindings 8 MOVE and Bindings
skipping to change at line 721 skipping to change at line 735
>> After Request: >> After Request:
URI 1 URI 2 URIX URI 1 URI 2 URIX
| | | | | |
| | | <---- URI Mappings | | | <---- URI Mappings
| | | | | |
+---------------------+ +---------------------+
| Resource R | | Resource R |
+---------------------+ +---------------------+
Figure 8 Figure 5
Although [WebDAV] allows a MOVE on a collection to be a non-atomic Although [WebDAV] allows a MOVE on a collection to be a non-atomic
operation, the MOVE operation defined here MUST be atomic. Even when operation, the MOVE operation defined here MUST be atomic. Even when
the Request-URI identifies a collection, the MOVE operation involves the Request-URI identifies a collection, the MOVE operation involves
only removing one binding to that collection and adding another. There only removing one binding to that collection and adding another. There
are no operations on bindings to any of its children, so the case of are no operations on bindings to any of its children, so the case of
MOVE on a collection is the same as the case of MOVE on a non-collection MOVE on a collection is the same as the case of MOVE on a non-collection
resource. Both are atomic. resource. Both are atomic.
8.1 Implementation Note 9 Bindings and Other Methods
In some situations, particularly when the destination is on a different
server from the original resource, the server may implement MOVE by
performing a COPY, performing some consistency maintenance on bindings
and properties, and then performing a DELETE. In the end, all of the
original bindings except the one corresponding to the Request-URI will
be associated with the new resource. The binding corresponding to the
URI in the Destination header will be associated with the new resource.
And the original resource together with the binding corresponding to the
Request-URI will have been deleted. This implementation is logically
equivalent to the definition of MOVE given in Section 8 above.
The consistency maintenance processing that is required for this
implementation is as follows:
The DAV:creationdate property of the new resource SHOULD have the same
value as the DAV:creationdate property of the old resource.
The DAV:getlastmodified property of the new resource SHOULD have the
same value as the DAV:getlastmodified property of the old resource.
All URIs that were bound to the original resource except for the
Request-URI MUST be bound instead to the new resource.
Consider again the case where a MOVE is issued to URI 3 for resource R
(which is also mapped to URI 1 and URI 2), with the Destination header
set to URIX. Unlike the previous example, in this implementation, after
successful completion of the MOVE operation, resource R has been
duplicated as resource R'. The original bindings corresponding to URI 1
and URI2 are now associated with R'. The binding corresponding to the
Request-URI (URI 3) has been removed. And a new binding has been
created which creates at least the URI mapping between URIX and resource
R'. Note that the server may reclaim the storage associated with
resource R once the MOVE operation has finished.
>> Before Request:
URI 1 URI 2 URI 3
| | |
| | | <---- URI Mappings
| | |
+---------------------+
| Resource R |
+---------------------+
>> After Request:
URI1 URI2 --------------------------------- URIX
| | |
----------------------------------------- | |
| | |
+---------------------+ +------------------------+
| Resource R | | Resource R' |
+---------------------+ +------------------------+
Figure 9
8.2 MOVE and Locks
The MOVE semantics defined in Section 8 above implies lock behavior that
is different from that specified in Section 7.7 of [WebDAV]. Section
7.7 of [WebDAV] states, "A successful MOVE request on a write locked
resource MUST NOT move the write lock with the resource."
However, the semantics of MOVE defined here say that MOVE does nothing
but remove one binding to a resource and create another binding to the
same resource. The resource itself is not modified. Its state after
the MOVE should be as nearly as possible identical to its state before
the MOVE. Therefore, if it was locked before the MOVE, it MUST be
locked after the MOVE, and with the same lock token. If this
requirement cannot be met, the MOVE MUST fail.
Specifically, the following rules apply to MOVE and locks:
1. If there is a lock on the resource before the MOVE, and that lock is
rooted at the resource (that is, it is not inherited from a parent
collection), the resource MUST still have that same lock after the
MOVE. (This conflicts with [WebDAV].)
2. If there is a lock on the resource at the destination URL before the
MOVE, and that lock is rooted at the destination resource (that is,
it is not inherited from a parent collection), that lock does not
apply to the resource that is moved to that Destination after the
MOVE. (This is consistent with [WebDAV].)
3. If the resource being moved inherits a lock from a parent collection,
and the resource is moved out of the tree affected by that lock, the
lock no longer applies to the resource after the MOVE. (This is
consistent with [WebDAV].)
4. If the resource at the destination URL inherits a lock from a parent
collection before the MOVE, the moved resource inherits that lock
after the MOVE. (This is consistent with [WebDAV].)
5. If there is a lock on the resource before the MOVE, and that lock is
rooted at the resource, and the resource at the destination URL
inherits a lock from a parent collection before the MOVE, the MOVE
MUST fail due to a conflict between rules 1 and 4. (This conflicts
with [WebDAV].)
6. If a collection is MOVEd, and there are some locked resources in that
collection, those resources MUST still have the same locks after the
MOVE. (This conflicts with [WebDAV].)
The results of applying these rules are as follows:
+-------------------------------------------------------------------+
| Before MOVE | After MOVE |
|---------------------------------------------| |
| Source Resource S | Destination Resource D | |
|--------------------------------------------------------------------
| no lock | no lock | no lock |
|-------------------|-------------------------|---------------------|
| no lock | lock rooted at D | no lock |
|-------------------|-------------------------|---------------------|
| no lock | inherited lock | D's inherited lock |
| | | applies |
|-------------------|-------------------------|---------------------|
| lock rooted at S | no lock | S's lock applies |
|-------------------|-------------------------|---------------------|
| lock rooted at S | lock rooted at D | S's lock applies |
|-------------------|-------------------------|---------------------|
| lock rooted at S | inherited lock | MOVE fails |
|-------------------|-------------------------|---------------------|
| inherited lock | no lock | no lock |
|-------------------|-------------------------|---------------------|
| inherited lock | lock rooted at D | no lock |
|-------------------|-------------------------|---------------------|
| inherited lock | inherited lock | D's inherited lock |
| | | applies |
+-------------------------------------------------------------------+
9 LOCK and UNLOCK
Bindings do not change the fundamental requirement on locks, stated in
section 8.10.3 of [WebDAV], that "a LOCK request on a resource MUST NOT
succeed if it can not be honored by all the URIs through which the
resource is accessible". The LOCK method locks the resource, and a lock
is visible via all URIs mapped to that resource. Similarly, a successful
UNLOCK issued via any URI mapping to a resource removes the lock from
the resource, and this lock removal is visible via all URI mappings.
When a resource is locked, the lock owner expects to be able to access
the resource -- using the same Request-URI that he used to lock the
resource -- for as long as he holds the lock. This would not be
possible if another user could move or delete any of the collections
corresponding to segments of the request-URI.
Consequently, for the duration of a lock, it MUST NOT be possible for a
principal other than the lock owner to make a locked resource
inaccessible via the URI mapping used to lock the resource. Only the
lock owner can move or delete any of the collections corresponding to
segments of the Request-URI. This restriction does not prevent others
from modifying those collections, by adding members to them, removing
members from them, or changing their property values.
For example, if a user locks /plants/herbs/rosemary.html, it is not
possible for another user to move /plants/herbs/ to
/plants/flowering/herbs/, or to completely delete /plants/herbs/, though
it is possible this delete operation may succeed in deleting everything
except for /plants/herbs/rosemary.html and /plants/herbs/.
Note that this requirement is weaker than the one implied by [WebDAV].
Sections 8.9.6 and 8.9.2 of [WebDAV] together imply that all URI
mappings to a locked resource must be protected. They forbid moving or
deleting any collection that has a locked resource as a descendent. It
is likely that in an environment where multiple URI mappings to a single
resource are common, it will be prohibitively expensive to enforce this
stronger constraint.
10 Bindings and Other Methods
This section describes the interaction of bindings with those HTTP This section describes the interaction of bindings with those HTTP
methods not yet explicitly discussed. The semantics of the methods GET, methods not yet explicitly discussed. The semantics of the methods GET,
HEAD, PUT, POST and OPTIONS are specified in [HTTP]. The semantics of HEAD, PUT, POST and OPTIONS are specified in [HTTP]. The semantics of
PROPFIND, PROPPATCH, and MKCOL are specified in [WebDAV]. PROPFIND, PROPPATCH, and MKCOL are specified in [WebDAV].
For these methods, no new complexities are introduced by allowing For these methods, no new complexities are introduced by allowing
explicit creation of multiple bindings to the same resource. When explicit creation of multiple bindings to the same resource. When
applied to static resources (that is, resources that are not CGI applied to static resources (that is, resources that are not CGI
scripts, Active Server Pages, etc.), they obey the following rule: scripts, Active Server Pages, etc.), they obey the following rule:
o The method submitted through one URI mapping MUST produce the same o A method submitted through one URI mapping, on success, MUST produce
results as the same method, with the same headers and entity body, the same results as the same method, with the same headers and entity
submitted through any other URI mapping to the same resource. body, submitted through any other URI mapping to the same resource.
When applied to dynamic resources, it is not possible to state any such When applied to dynamic resources, it is not possible to state any such
rule. For any method, a dynamic resource may be sensitive to the URI rule. For any method, a dynamic resource may be sensitive to the URI
mapping used to access it. The resource may produce different results mapping used to access it. The resource may produce different results
depending upon which URI mapping was used to submit the request. depending upon which URI mapping was used to submit the request.
Nevertheless, servers MAY allow new bindings to dynamic resources to be Nevertheless, servers MAY allow new bindings to dynamic resources to be
created using BIND. created using BIND.
11 Determining Whether Two Bindings Are to the Same Resource 10 Determining Whether Two Bindings Are to the Same Resource
It is useful to have some way of determining whether two bindings are to It is useful to have some way of determining whether two bindings are to
the same resource. Two different resources might have identical the same resource. Two different resources might have identical
contents and identical values for the properties defined in [WebDAV]. contents and identical values for the properties defined in [WebDAV].
Although the DAV:bindings property defined in Section 15.1 provides this Although the DAV:bindings property defined in Section 13.1 provides this
information, it is an optional property. information, it is an optional property.
The REQUIRED DAV:guid property defined in Section 15.2 is a resource The REQUIRED DAV:resourceid property defined in Section 13.2 is a
identifier, which MUST be unique across all resources for all time. If
the values of DAV:guid returned by PROPFIND requests through two
bindings are identical, the client can be assured that the two bindings
are to the same resource.
The DAV:guid property is created, and its value assigned, when the resource identifier, which MUST be unique across all resources for all
resource is created. The value of DAV:guid MUST NOT be changed. Even time. If the values of DAV:resourceid returned by PROPFIND requests
after the resource is no longer accessible through any URI, that value through two bindings are identical, the client can be assured that the
MUST NOT be reassigned to another resource's DAV:guid property. two bindings are to the same resource.
11.1 davresourceid URI Scheme The DAV:resourceid property is created, and its value assigned, when the
resource is created. The value of DAV:resourceid MUST NOT be changed.
Even after the resource is no longer accessible through any URI, that
value MUST NOT be reassigned to another resource's DAV:resourceid
property.
The value of DAV:guid is a URI and may use any URI scheme that Any method that creates a new resource MUST assign a new, unique value
to its DAV:resourceid property. For example, a PUT that creates a new
resource must assign a new, unique value to its DAV:resourceid property.
A COPY, since it creates a new resource at the Destination URI, must
assign a new, unique value to its DAV:resourceid property.
On the other hand, any method that affects an existing resource MUST NOT
change the value of its DAV:resourceid property. For example, a PUT
that updates an existing resource must not change the value of its
DAV:resourceid property. A MOVE, since it does not create a new
resource, but only changes the location of an existing resource, must
not change the value of its DAV:resourceid property.
10.1 resourceid URI Scheme
The value of DAV:resourceid is a URI and may use any URI scheme that
guarantees the uniqueness of the value across all resources for all guarantees the uniqueness of the value across all resources for all
time. The davresourceid URI scheme defined here is an example of an time. The resourceid URI scheme defined here is an example of an
acceptable URI scheme. acceptable URI scheme.
The davresourceid URI scheme requires the use of the Universal Unique The resourceid URI scheme requires the use of the Universal Unique
Identifier (UUID) mechanism, as described in [ISO-11578]. Davresourceid Identifier (UUID) mechanism, as described in [ISO-11578]. UUID
generators may choose between two methods of creating the identifiers. generators may choose between two methods of creating the identifiers.
They can either generate a new UUID for every davresourceid they create They can either generate a new UUID for every identifier they create or
or they can create a single UUID and then add extension characters. If they can create a single UUID and then add extension characters. If the
the second method is selected, then the program generating the second method is selected, then the program generating the extensions
extensions MUST guarantee that the same extension will never be used MUST guarantee that the same extension will never be used twice with the
twice with the associated UUID. associated UUID.
DAVResourceID-URI = "davresourceid:" UUID [Extension] ; The UUID resourceid-URI = "resourceid:" UUID [Extension] ; The UUID production is
production is the string representation of a UUID, as defined in [ISO- the string representation of a UUID, as defined in [ISO-11578]. Note
11578]. Note that white space (LWS) is not allowed between elements of that white space (LWS) is not allowed between elements of this
this production. production.
Extension = path ; path is defined in Section 3.3 of [URI]. Extension = path ; path is defined in Section 3.3 of [URI].
12 Discovering the Bindings to a Resource 11 Discovering the Bindings to a Resource
An OPTIONAL DAV:bindings property on a resource provides a list of the An OPTIONAL DAV:bindings property on a resource provides a list of the
bindings that associate URI segments with that resource. If the bindings that associate URI segments with that resource. If the
DAV:bindings property exists on a given resource, it MUST provide a DAV:bindings property exists on a given resource, it MUST contain a
complete list of all bindings to that resource. By retrieving this complete list of all bindings to that resource. A PROPFIND requesting
property, a client can discover the bindings that point to the resource DAV:bindings MUST return only those bindings that the client is
and the collections that contain bindings to the resource. As for all authorized to see. By retrieving this property, a client can discover
DAV: properties, this specification is silent as to how the DAV:bindings
property is implemented on the server. the bindings that point to the resource and the collections that contain
bindings to the resource.
Rationale: A number of scenarios require clients to navigate from a Rationale: A number of scenarios require clients to navigate from a
resource to the bindings that point to it, and to the collections that resource to the bindings that point to it, and to the collections that
contain those bindings. This capability is particularly important for contain those bindings. This capability is particularly important for
Document Management Systems. Their clients may need to determine, for Document Management Systems. Their clients may need to determine, for
any object in the DMS, what collections contain bindings to that object. any object in the DMS, what collections contain bindings to that object.
This information can be used for upward navigation through a hierarchy This information can be used for upward navigation through a hierarchy
or to discover related documents in other collections. or to discover related documents in other collections.
Risks: When deciding whether to support the DAV:bindings property, Risks: When deciding whether to support the DAV:bindings property,
server implementers / administrators should balance the benefits it server implementers / administrators should balance the benefits it
provides against the cost of maintaining the property and the security provides against the cost of maintaining the property and the security
risks enumerated in Sections 18.4 and 18.5. risks enumerated in Sections 16.4 and 16.5.
13 Status Codes 12 Status Codes
13.1 506 Loop Detected 12.1 506 Loop Detected
The 506 (Loop Detected) status code indicates that the server terminated The 506 (Loop Detected) status code indicates that the server terminated
an operation because it encountered an infinite loop while processing a an operation because it encountered an infinite loop while processing a
request with "Depth: infinity". request with "Depth: infinity".
When this status code is the top-level status code for the operation, it When this status code is the top-level status code for the operation, it
indicates that the entire operation failed. In this case, the Loop indicates that the entire operation failed.
header can be used in the response to identify the URI that caused the
failure.
When this status code occurs inside a multistatus response, it indicates When this status code occurs inside a multistatus response, it indicates
only that a loop is being terminated, but does not indicate failure of only that a loop is being terminated, but does not indicate failure of
the operation as a whole. the operation as a whole.
For example, consider a PROPFIND request on the following collection: For example, consider a PROPFIND request on the following collection:
Coll-1 (bound to collection C) Coll-1 (bound to collection C)
Foo (bound to resource R) Foo (bound to resource R)
Bar (bound to collection C) Bar (bound to collection C)
>> Request: >> Request:
skipping to change at line 1066 skipping to change at line 925
<D:href>http://www.somehost.com/Coll-1/Bar</D:href> <D:href>http://www.somehost.com/Coll-1/Bar</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<D:displayname/> <D:displayname/>
</D:prop> </D:prop>
<D:status>HTTP/1.1 506 Loop Detected</D:status> <D:status>HTTP/1.1 506 Loop Detected</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
13.2 507 Loop Forbidden 12.2 507 Cross-Server Binding Forbidden
The server does not allow creation of bindings that create loops.
13.3 508 Cross-Server Binding Forbidden
The server is unable to create the requested binding because it would The server is unable to create the requested binding because it would
bind a segment in a collection on one server to a resource on a bind a segment in a collection on one server to a resource on a
different server. different server.
14 Headers 13 Properties
14.1 All-Bindings Request Header
All-Bindings = "All-Bindings" ":"
The All-Bindings request header may be used with DELETE requests to
instruct the server to remove all bindings to the resource identified by
the Request-URI.
14.2 Loop Header
Loop = "Loop" ":" Coded-URL
The Loop header is used in 506 (Loop Detected) responses to identify the
URI that caused the operation to fail. Note that the Coded-URL
production is defined in Section 9.4 of [WebDAV].
15 Properties
15.1 bindings Property 13.1 bindings Property
Name: bindings Name: bindings
Namespace: DAV: Namespace: DAV:
Purpose: Enables clients to discover, for any resource, what bindings Purpose: Enables clients to discover, for any resource, what bindings
point to it and what collections contain those bindings. point to it and what collections contain those bindings.
This is an optional property. If present on a given This is an optional property. If present on a given
resource, it is a read-only property, maintained by the resource, it is a read-only property, maintained by the
server, and contains a complete list of all bindings to that server, and contains a complete list of all bindings to that
resource. resource.
Value: List of href / segment pairs for all of the bindings that Value: List of href / segment pairs for all of the bindings that
skipping to change at line 1118 skipping to change at line 955
absolute URI for one URI mapping of the collection absolute URI for one URI mapping of the collection
containing the binding. Since there may be multiple URI containing the binding. Since there may be multiple URI
mappings for this collection, it is necessary to select one mappings for this collection, it is necessary to select one
(preferably the URI mapping contained in the Request-URI of (preferably the URI mapping contained in the Request-URI of
the BIND request) for use in the DAV:bindings property. The the BIND request) for use in the DAV:bindings property. The
segment is the URI segment that identifies the binding segment is the URI segment that identifies the binding
within that collection. within that collection.
<!ELEMENT bindings ((href, segment)*)> <!ELEMENT bindings ((href, segment)*)>
15.2 guid Property 13.2 resourceid Property
Name: guid Name: resourceid
Namespace: DAV: Namespace: DAV:
Purpose: Enables clients to determine whether two bindings are for Purpose: Enables clients to determine whether two bindings are for
the same resource. the same resource.
Value: URI that is guaranteed unique across all resources for all Value: URI that is guaranteed unique across all resources for all
time. It may be of the davresourceid URI scheme defined in time. It may be of the resourceid URI scheme
Section 12.1 or any other URI scheme that guarantees this defined in Section 10.1 or any other URI scheme that
uniqueness. guarantees this uniqueness.
<!ELEMENT guid (href)> <!ELEMENT resourceid (href)>
16 XML Elements 14 XML Elements
16.1 segment XML Element 14.1 segment XML Element
Name: segment Name: segment
Namespace: DAV: Namespace: DAV:
Purpose: The segment that names a binding, used in the DAV:bindings Purpose: The segment that names a binding, used in the DAV:bindings
property. property.
Value: segment ; as defined in section 3.3 of [URI]. Value: segment ; as defined in section 3.3 of [URI].
<!ELEMENT segment (#PCDATA)> <!ELEMENT segment (#PCDATA)>
17 Capability Discovery 15 Capability Discovery
Sections 9.1 and 15 of [WebDAV] describe the use of compliance classes Sections 9.1 and 15 of [WebDAV] describe the use of compliance classes
with the DAV header in responses to OPTIONS, to indicate which parts of with the DAV header in responses to OPTIONS, to indicate which parts of
the Web Distributed Authoring protocols the resource supports. This the WebDAV Distributed Authoring protocol the resource supports. This
specification defines an OPTIONAL extension to [WebDAV]. It defines a specification defines an OPTIONAL extension to [WebDAV]. It defines a
new compliance class, called bindings, for use with the DAV header in new compliance class, called bindings, for use with the DAV header in
responses to OPTIONS requests. If a resource does support bindings, its responses to OPTIONS requests. If a resource does support bindings, its
response to an OPTIONS request MUST indicate that it does, by listing response to an OPTIONS request may indicate that it does, by listing the
the new BIND method as one it supports, and by listing the new bindings new BIND method as one it supports, and by listing the new bindings
compliance class in the DAV header. compliance class in the DAV header.
When responding to an OPTIONS request, any type of resource can include When responding to an OPTIONS request, any type of resource can include
bindings in the value of the DAV header. Doing so indicates that the bindings in the value of the DAV header. Doing so indicates that the
server permits a binding at the request URI. server permits a binding at the request URI.
17.1 Example: Discovery of Support for Bindings 15.1 Example: Discovery of Support for Bindings
>> Request: >> Request:
OPTIONS /somecollection/someresource HTTP/1.1 OPTIONS /somecollection/someresource HTTP/1.1
HOST: somehost.org HOST: somehost.org
>> Response: >> Response:
HTTP/1.1 200 OK HTTP/1.1 200 OK
Date: Tue, 20 Jan 1998 20:52:29 GMT Date: Tue, 20 Jan 1998 20:52:29 GMT
Connection: close Connection: close
Accept-Ranges: none Accept-Ranges: none
Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE, MKCOL, Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE, MKCOL,
PROPFIND, PROPPATCH, LOCK, UNLOCK, BIND PROPFIND, PROPPATCH, LOCK, UNLOCK, BIND
Public: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE, MKCOL, Public: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE, MKCOL,
PROPFIND, PROPPATCH, LOCK, UNLOCK, BIND, MKREF, ORDERPATCH PROPFIND, PROPPATCH, LOCK, UNLOCK, BIND, MKREF, ORDERPATCH
DAV: 1, 2, bindings DAV: 1, 2, bindings
The DAV header in the response indicates that the resource The DAV header in the response indicates that the resource
/somecollection/someresource is level 1 and level 2 compliant, as /somecollection/someresource is level 1 and level 2 compliant, as
skipping to change at line 1186 skipping to change at line 1023
PROPFIND, PROPPATCH, LOCK, UNLOCK, BIND, MKREF, ORDERPATCH PROPFIND, PROPPATCH, LOCK, UNLOCK, BIND, MKREF, ORDERPATCH
DAV: 1, 2, bindings DAV: 1, 2, bindings
The DAV header in the response indicates that the resource The DAV header in the response indicates that the resource
/somecollection/someresource is level 1 and level 2 compliant, as /somecollection/someresource is level 1 and level 2 compliant, as
defined in [WebDAV]. In addition, /somecollection/someresource supports defined in [WebDAV]. In addition, /somecollection/someresource supports
bindings. The Allow header indicates that BIND requests can be bindings. The Allow header indicates that BIND requests can be
submitted to /somecollection/someresource. The Public header shows that submitted to /somecollection/someresource. The Public header shows that
other Request-URIs on the server support additional methods. other Request-URIs on the server support additional methods.
18 Security Considerations 16 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 protocol Distributed Authoring Protocol specification also apply to this protocol
specification. In addition, bindings introduce several new security specification. In addition, bindings introduce several new security
concerns and increase the risk of some existing threats. These issues concerns and increase the risk of some existing threats. These issues
are detailed below. are detailed below.
18.1 Privacy Concerns 16.1 Privacy Concerns
In a context where cross-server bindings are supported, creating In a context where cross-server bindings are supported, creating
bindings on a trusted server may make it possible for a hostile agent to 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 different induce users to send private information to a target on a different
server. server.
18.2 Redirect Loops 16.2 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 target create loops accidentally or maliciously. If the binding and its target
are on the same server, the server may be able to detect BIND requests are on the same server, the server may be able to detect BIND requests
that would create loops. Servers are required to detect loops that are that would create loops. Servers are required to detect loops that are
caused by bindings to collections during the processing of any requests caused by bindings to collections during the processing of any requests
with "Depth: infinity". with "Depth: infinity".
18.3 Bindings, and Denial of Service 16.3 Bindings, and Denial of Service
Denial of service attacks were already possible by posting URLs that Denial of service attacks were already possible by posting URLs that
were intended for limited use at heavily used Web sites. The were intended for limited use at heavily used Web sites. The
introduction of BIND creates a new avenue for similar denial of service introduction of BIND creates a new avenue for similar denial of service
attacks. If cross-server bindings are supported, clients can now create attacks. If cross-server bindings are supported, clients can now create
bindings at heavily used sites to target locations that were not bindings at heavily used sites to target locations that were not
designed for heavy usage. designed for heavy usage.
18.4 Private Locations May Be Revealed 16.4 Private Locations May Be Revealed
If the DAV:bindings property is maintained on a resource, the owners of If the DAV:bindings property is maintained on a resource, the owners of
the bindings risk revealing private locations. The directory structures the bindings risk revealing private locations. The directory structures
where bindings are located are available to anyone who has access to the where bindings are located are available to anyone who has access to the
DAV:bindings property on the resource. Moving a binding may reveal its DAV:bindings property on the resource. Moving a binding may reveal its
new location to anyone with access to DAV:bindings on its resource. new location to anyone with access to DAV:bindings on its resource.
18.5 DAV:bindings and Denial of Service 16.5 DAV:bindings and Denial of Service
If the server maintains the DAV:bindings property in response to If the server maintains the DAV:bindings 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 the hostile attempts to make it devote resources to adding bindings to the
list. list.
19 Internationalization Considerations 17 Internationalization Considerations
This specification follows the practices of [WebDAV] in encoding all This specification follows the practices of [WebDAV] in encoding all
human-readable content using XML [XML] and in the treatment of names. human-readable content using XML [XML] and in the treatment of names.
Consequently, this specification complies with the IETF Character Set Consequently, this specification complies with the IETF Character Set
Policy [Alvestrand]. Policy [RFC2277].
WebDAV applications MUST support the character set tagging, character WebDAV applications MUST support the character set tagging, character
set encoding, and the language tagging functionality of the XML set encoding, and the language tagging functionality of the XML
specification. This constraint ensures that the human-readable content specification. This constraint ensures that the human-readable content
of this specification complies with [Alvestrand]. of this specification complies with [RFC2277].
As in [WebDAV}, names in this specification fall into three categories: As in [WebDAV], names in this specification fall into three categories:
names of protocol elements such as methods and headers, names of XML names of protocol elements such as methods and headers, names of XML
elements, and names of properties. Naming of protocol elements follows elements, and names of properties. Naming of protocol elements follows
the precedent of HTTP, using English names encoded in USASCII for the precedent of HTTP, using English names encoded in USASCII for
methods and headers. The names of XML elements used in this methods and headers. The names of XML elements used in this
specification are English names encoded in UTF-8. specification are English names encoded in UTF-8.
For error reporting, [WebDAV] follows the convention of HTTP/1.1 status For error reporting, [WebDAV] follows the convention of HTTP/1.1 status
codes, including with each status code a short, English description of codes, including with each status code a short, English description of
the code (e.g., 423 Locked). Internationalized applications will ignore the code (e.g., 423 Locked). Internationalized applications will ignore
this message, and display an appropriate message in the user's language this message, and display an appropriate message in the user's language
and character set. and character set.
This specification introduces no new strings that are displayed to users
as part of normal, error-free operation of the protocol.
For rationales for these decisions and advice for application For rationales for these decisions and advice for application
implementors, see [WebDAV]. implementors, see [WebDAV].
20 IANA Considerations 18 IANA Considerations
This document uses the namespaces defined by [WebDAV] for properties and This document uses the namespaces defined by [WebDAV] for properties and
XML elements. All other IANA considerations mentioned in [WebDAV] also XML elements. All other IANA considerations mentioned in [WebDAV] also
apply to this document. apply to this document.
In addition, this document defines new HTTP/1.1 status codes 506, 507, In addition, this document defines the new resourceid URI Scheme in
and 508 in Section 13. Section 10.1 and the new HTTP/1.1 status codes 506 and 507in Section 12.
21 Copyright 19 Copyright
To be supplied by the RFC Editor. To be supplied by the RFC Editor.
22 Intellectual Property 20 Intellectual Property
To be supplied by the RFC Editor. To be supplied by the RFC Editor.
23 Acknowledgements 21 Acknowledgements
This draft has benefited from thoughtful discussion by Jim Amsden, Steve This draft has benefited from thoughtful discussion by Jim Amsden, Peter
Carter, Ken Coar, Ellis Cohen, Dan Connolly, Bruce Cragun, Spencer Carlson, Steve Carter, Tyson Chihaya, Ken Coar, Ellis Cohen, Dan
Dawkins, Mark Day, Rajiv Dulepet, David Durand, Roy Fielding, Yaron Connolly, Bruce Cragun, Spencer Dawkins, Mark Day, Rajiv Dulepet, David
Goland, Fred Hitt, Alex Hopmann, Marcus Jager, Chris Kaler, Manoj Durand, Roy Fielding, Yaron Goland, Fred Hitt, Alex Hopmann, James Hunt,
Kasichainula, Rohit Khare, Daniel LaLiberte, Steve Martin, Larry Marcus Jager, Chris Kaler, Manoj Kasichainula, Rohit Khare, Daniel
Masinter, Jeff McAffer, Surendra Koduru Reddy, Max Rible, Sam Ruby, LaLiberte, Steve Martin, Larry Masinter, Jeff McAffer, Surendra Koduru
Bradley Sergeant, Nick Shelness, John Stracke, John Tigue, John Turner, Reddy, Max Rible, Sam Ruby, Bradley Sergeant, Nick Shelness, John
Kevin Wiggen, and others. Stracke, John Tigue, John Turner, Kevin Wiggen, and others.
24 References 22 References
[RFC2277] H.T. Alvestrand, "IETF Policy on Character Sets and
Languages." RFC 2277, BCP 18. Uninett. January, 1998.
[URI] T. Berners-Lee, R. Fielding, L. Masinter, "Uniform Resource [URI] T. Berners-Lee, R. Fielding, L. Masinter, "Uniform Resource
Identifiers (URI): Generic Syntax." RFC 2396. MIT/LCS, U.C. Irvine, Identifiers (URI): Generic Syntax." RFC 2396. MIT/LCS, U.C. Irvine,
Xerox. August, 1998. Xerox. August, 1998.
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate Requirement [RFC2119] S. Bradner, "Key words for use in RFCs to Indicate Requirement
Levels." RFC 2119, BCP 14. Harvard University. March, 1997. Levels." RFC 2119, BCP 14. Harvard University. March, 1997.
[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)." World Wide Web Consortium Recommendation REC-xml-
skipping to change at line 1320 skipping to change at line 1163
2616. UC Irvine, Compaq, W3C, Xerox, Microsoft. June, 1999. 2616. UC Irvine, Compaq, W3C, Xerox, Microsoft. June, 1999.
[WebDAV] Y. Y. Goland, E. J. Whitehead, Jr., A. Faizi, S. R. Carter, D. [WebDAV] Y. Y. Goland, E. J. Whitehead, Jr., A. Faizi, S. R. Carter, D.
Jensen, "HTTP Extensions for Distributed Authoring - WebDAV." RFC 2518. Jensen, "HTTP Extensions for Distributed Authoring - WebDAV." RFC 2518.
Microsoft, U.C. Irvine, Netscape, Novell. February, 1999. Microsoft, U.C. Irvine, Netscape, Novell. February, 1999.
[ISO-11578] ISO (International Organization for Standardization), [ISO-11578] ISO (International Organization for Standardization),
ISO/IEC 11578:1996. "Information technology - Open Systems ISO/IEC 11578:1996. "Information technology - Open Systems
Interconnection - Remote Procedure Call (RPC)." Interconnection - Remote Procedure Call (RPC)."
[OC] J. Slein, E.J. Whitehead Jr., J. Davis, G. Clemm, C. Fay, J.
Crawford, T. Chihaya, "WebDAV Ordered Collections." Internet Draft (work
in progress) draft-ietf-webdav-ordering-protocol-00. Xerox, UC Irvine,
CourseNet, Rational, FileNet, IBM, DataChannel. August, 1999.
[RR] J. Slein, E.J. Whitehead Jr., J. Davis, G. Clemm, C. Fay, J. [RR] J. Slein, E.J. Whitehead Jr., J. Davis, G. Clemm, C. Fay, J.
Crawford, T. Chihaya, "WebDAV Redirect References." Internet Draft (work Crawford, "WebDAV Redirect References." Internet Draft (work
in progress) draft-ietf-webdav-redirectref-protocol-00. Xerox, UC in progress) draft-ietf-webdav-redirectref-protocol-02. Xerox, UC
Irvine, CourseNet, Rational, FileNet, IBM, DataChannel. August, 1999. Irvine, CourseNet, Rational, FileNet, IBM. December, 1999.
25 Authors' Addresses 23 Authors' Addresses
J. Slein J. 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
E. J. Whitehead, Jr. E. J. Whitehead, Jr.
Dept. of Information and Computer Science Dept. of Information and Computer Science
University of California, Irvine University of California, Irvine
skipping to change at line 1363 skipping to change at line 1201
Lexington, MA 02173-3104 Lexington, MA 02173-3104
Email: gclemm@rational.com Email: gclemm@rational.com
C. Fay C. Fay
FileNet Corporation FileNet Corporation
3565 Harbor Boulevard 3565 Harbor Boulevard
Costa Mesa, CA 92626-1420 Costa Mesa, CA 92626-1420
Email: cfay@filenet.com Email: cfay@filenet.com
J. Crawford J. Crawford
IBM IBM Research
P.O. Box 704
Yorktown Heights, NY 10598
Email: ccjason@us.ibm.com Email: ccjason@us.ibm.com
T. Chihaya 24 Appendices
DataChannel, Inc.
155 108th Ave. N.E., Suite 400
Bellevue, WA 98004
Email: Tyson@DataChannel.com
26 Appendices
26.1 Appendix 1: Extensions to the WebDAV Document Type Definition 24.1 Appendix 1: Extensions to the WebDAV Document Type Definition
<!--============= XML Elements from Section 16 ================--> <!--============= XML Elements from Section 14 ================-->
<!ELEMENT segment (#PCDATA)> <!ELEMENT segment (#PCDATA)>
<!--============= Property Elements from Section 13 ==================-- <!--============= Property Elements from Section 13 ===========-->
>
<!ELEMENT bindings ((href, segment)*)> <!ELEMENT bindings ((href, segment)*)>
<!ELEMENT guid (href)> <!ELEMENT resourceid (href)>
Expires April 15, 2000 Expires June 17, 2000
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