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HTTP Extensions for Distributed Authoring on the World Wide Web -- WEBDAV
Status of this Memo
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Distribution of this document is unlimited. Please send comments to
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Discussions of the WEBDAV working group are archived at
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Abstract
This document specifies a set of methods, headers, and content-types
ancillary to HTTP/1.1 for the management of resource properties,
creation and management of resource collections, namespace
manipulation, and resource locking (collision avoidance).
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Contents
STATUS OF THIS MEMO ..................................................1
ABSTRACT .............................................................1
CONTENTS .............................................................2 MEMO...................................................1
ABSTRACT..............................................................1
CONTENTS..............................................................2
1 INTRODUCTION .......................................................7
2 NOTATIONAL CONVENTIONS .............................................8
3 TERMINOLOGY ........................................................8
4 DATA MODEL FOR RESOURCE PROPERTIES .................................8
3.1 .................................9
4.1 The Resource Property Model .....................................8
3.2 .....................................9
4.2 Existing Metadata Proposals .....................................9
3.3 ....................................10
4.3 Properties and HTTP Headers ....................................10
3.4
4.4 Property Values ................................................10
3.5
4.5 Property Names .................................................10
3.6 .................................................11
4.6 Media Independent Links ........................................11
4
5 COLLECTIONS OF WEB RESOURCES ......................................11
4.1
5.1 HTTP URL Namespace Model .......................................12
5.2 Collection Resources ...........................................11
4.2 ...........................................12
5.3 Creation and Retrieval of Collection Resources .................12
4.3 HTTP URL Namespace Model .......................................12
4.4 .................13
5.4 Source Resources and Output Resources ..........................12
5 ..........................14
6 LOCKING ...........................................................13
5.1 ...........................................................15
6.1 Exclusive Vs. Shared Locks .....................................14
5.2 .....................................15
6.2 Required Support ...............................................15
5.3 ...............................................16
6.3 Lock Tokens ....................................................15
5.4 ....................................................16
6.4 opaquelocktoken Lock Token URI Scheme ..........................15
5.5 ..........................17
6.4.1 Node Field Generation Without the IEEE 802 Address ..........17
6.5 Lock Capability Discovery ......................................16
5.6 ......................................19
6.6 Active Lock Discovery ..........................................16
5.7 ..........................................19
6.7 Usage Considerations ...........................................16
6 ...........................................19
7 WRITE LOCK ........................................................17
6.1 ........................................................20
7.1 Methods Restricted by Write Locks ..............................17
6.2 ..............................20
7.2 Write Locks and Lock Tokens ....................................20
7.3 Write Locks and Properties .....................................18
6.3 .....................................20
7.4 Write Locks and Null Resources .................................18
6.4 .................................21
7.5 Write Locks and Collections ....................................18
6.5 ....................................21
7.6 Write Locks and the If Request Header ..........................19
6.5.1 ..........................22
7.6.1 Example - Write Lock .........................................19
6.6 ........................................22
7.7 Write Locks and COPY/MOVE ......................................20
6.7 ......................................22
7.8 Refreshing Write Locks .........................................20
7 .........................................23
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8 HTTP METHODS FOR DISTRIBUTED AUTHORING ............................20
7.1 ............................23
8.1 PROPFIND .......................................................21
7.1.1 .......................................................24
8.1.1 Example - Retrieving Named Properties ........................22
7.1.2 .......................25
8.1.2 Example - Using allprop to Retrieve All Properties ...........23
7.1.3 ..........26
8.1.3 Example - Using propname to Retrieve all Property Names ......25
7.2 .....29
8.2 PROPPATCH ......................................................27
7.2.1 ......................................................30
8.2.1 Status Codes for use with Multi-Status .......................27
7.2.2 207 (Multi-Status) ................31
8.2.2 Example - PROPPATCH ..........................................28
7.3 .........................................31
8.3 MKCOL Method ...................................................29
7.3.1 ...................................................32
8.3.1 Request ......................................................29
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7.3.2 Response .....................................................32
8.3.2 Status Codes ...............................................30
7.3.3 ................................................33
8.3.3 Example - MKCOL ..............................................30
7.4 .............................................33
8.4 GET, HEAD for Collections ......................................31
7.5 ......................................34
8.5 POST for Collections ...........................................31
7.6 ...........................................34
8.6 DELETE .........................................................31
7.6.1 .........................................................34
8.6.1 DELETE for Non-Collection Resources ..........................31
7.6.2 .........................34
8.6.2 DELETE for Collections .......................................31
7.7 ......................................34
8.7 PUT ............................................................32
7.7.1 ............................................................35
8.7.1 PUT for Non-Collection Resources .............................32
7.7.2 ............................35
8.7.2 PUT for Collections ..........................................33
7.8 .........................................36
8.8 COPY Method ....................................................33
7.8.1 ....................................................36
8.8.1 COPY for HTTP/1.1 resources ..................................33
7.8.2 .................................36
8.8.2 COPY for Properties ..........................................34
7.8.3 .........................................36
8.8.3 COPY for Collections .........................................34
7.8.4 ........................................37
8.8.4 COPY and the Overwrite Header ................................35
7.8.5 ...............................38
8.8.5 Status Codes .................................................35
7.8.6 ................................................38
8.8.6 Example - COPY with Overwrite ................................36
7.8.7 ...............................39
8.8.7 Example - COPY with No Overwrite .............................36
7.8.8 ............................39
8.8.8 Example - COPY of a Collection ...............................36
7.9 ..............................39
8.9 MOVE Method ....................................................37
7.9.1 ....................................................40
8.9.1 MOVE for Properties ..........................................37
7.9.2 .........................................40
8.9.2 MOVE for Collections .........................................38
7.9.3 ........................................41
8.9.3 MOVE and the Overwrite Header ................................38
7.9.4 ...............................42
8.9.4 Status Codes .................................................39
7.9.5 ................................................42
8.9.5 Example - MOVE of a Non-Collection ...........................39
7.9.6 ..........................42
8.9.6 Example - MOVE of a Collection ...............................39
7.10 ..............................43
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8.10 LOCK Method ...................................................40
7.10.1 ....................................................43
8.10.1 Operation ...................................................40
7.10.2 ...................................................44
8.10.2 The Effect of Locks on Properties and Collections ...........41
7.10.3 ...........44
8.10.3 Locking Replicated Resources ................................41
7.10.4 ................................44
8.10.4 Depth and Locking ...........................................41
7.10.5 ...........................................44
8.10.5 Interaction with other Methods ..............................42
7.10.6 ..............................45
8.10.6 Lock Compatibility Table ....................................42
7.10.7 ....................................45
8.10.7 Status Codes ................................................42
7.10.8 ................................................46
8.10.8 Example - Simple Lock Request ...............................43
7.10.9 ...............................46
8.10.9 Example - Refreshing a Write Lock ...........................44
7.10.10 ...........................48
8.10.10 Example - Multi-Resource Lock Request ......................45
7.11 ......................49
8.11 UNLOCK Method .................................................46
7.11.1 ..................................................50
8.11.1 Example - UNLOCK ............................................46
8 ............................................50
9 HTTP HEADERS FOR DISTRIBUTED AUTHORING ............................47
8.1 ............................51
9.1 DAV Header .....................................................47
8.2 .....................................................51
9.2 Depth Header ...................................................47
8.3 ...................................................51
9.3 Destination Header .............................................48
8.4 .............................................52
9.4 If Header ......................................................48
8.4.1 ......................................................52
9.4.1 No-tag-list Production .......................................49
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8.4.2 ......................................53
9.4.2 Tagged-list Production .......................................49
8.4.3 ......................................53
9.4.3 not Production ...............................................50
8.4.4 ..............................................54
9.4.4 Matching Function ............................................50
8.4.5 ...........................................54
9.4.5 If Header and Non-DAV Compliant Proxies ......................51
8.5 .....................55
9.5 Lock-Token Request Header ......................................51
8.6 ..............................................55
9.6 Overwrite Header ...............................................51
8.7 ...............................................55
9.7 Status-URI Response Header .....................................51
8.8 .....................................55
9.8 Timeout Request Header .........................................52
9 .........................................56
10 STATUS CODE EXTENSIONS TO HTTP/1.1 ................................53
9.1 ..............................57
10.1 102 Processing .................................................53
9.2 .................................................57
10.2 207 Multi-Status ...............................................53
9.3 ...............................................57
10.3 422 Unprocessable Entity .......................................53
9.4 .......................................57
10.4 423 Locked .....................................................53
9.5 .....................................................58
10.5 424 Method Failure .............................................53
9.6 425 Failed Dependency ..........................................58
10.6 507 Insufficient Space on Resource .............................53
10 Storage .......................................58
11 MULTI-STATUS RESPONSE ............................................54
11 ...........................................58
12 XML ELEMENT DEFINITIONS ..........................................54
11.1 .........................................58
12.1 activelock XML Element ........................................54
11.1.1 .........................................58
12.1.1 depth XML Element ...........................................54
11.1.2 ...........................................59
12.1.2 locktoken XML Element .......................................54
11.1.3 .......................................59
12.1.3 timeout XML Element .........................................54
11.2 .........................................59
12.2 collection XML Element ........................................55
11.3 .........................................59
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12.3 href XML Element ..............................................55
11.4 ...............................................59
12.4 link XML Element ..............................................55
11.4.1 ...............................................60
12.4.1 dst XML Element .............................................55
11.4.2 .............................................60
12.4.2 src XML Element .............................................55
11.5 .............................................60
12.5 lockentry XML Element .........................................56
11.6 ..........................................60
12.6 lockinfo XML Element ..........................................56
11.7 ...........................................60
12.7 lockscope XML Element .........................................56
11.7.1 ..........................................61
12.7.1 exclusive XML Element .......................................56
11.7.2 .......................................61
12.7.2 shared XML Element ..........................................56
11.8 ..........................................61
12.8 locktype XML Element ..........................................56
11.8.1 ...........................................61
12.8.1 write XML Element ...........................................57
11.9 ...........................................61
12.9 multistatus XML Element .......................................57
11.9.1 ........................................62
12.9.1 response XML Element ........................................57
11.9.2 ........................................62
12.9.2 responsedescription XML Element .............................58
11.10 owner .............................63
12.10owner XML Element ............................................58
11.11 prop ..............................................63
12.11prop XML element .............................................58
11.12 propertybehavior ...............................................63
12.12propertybehavior XML element .................................59
11.12.1 ...................................63
12.12.1 keepalive XML element ......................................59
11.12.2 ......................................64
12.12.2 omit XML element ...........................................59
11.13 propertyupdate ...........................................64
12.13propertyupdate XML element ...................................60
11.13.1 .....................................64
12.13.1 remove XML element .........................................60
11.13.2 .........................................65
12.13.2 set XML element ............................................60
11.14 propfind ............................................65
12.14propfind XML Element .........................................60
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11.14.1 ...........................................65
12.14.1 allprop XML Element ........................................61
11.14.2 ........................................65
12.14.2 propname XML Element .......................................61
12 .......................................66
13 DAV PROPERTIES ...................................................61
12.1 ..................................................66
13.1 creationdate Property .........................................61
12.2 ..........................................66
13.2 displayname Property ..........................................61
12.3 ...........................................66
13.3 getcontentlanguage Property ...................................62
12.4 ....................................67
13.4 getcontentlength Property .....................................62
12.5 ......................................67
13.5 getcontenttype Property .......................................62
12.6 ........................................67
13.6 getetag Property ..............................................62
12.7 ...............................................67
13.7 getlastmodified Property ......................................63
12.8 .......................................68
13.8 lockdiscovery Property ........................................63
12.8.1 .........................................68
13.8.1 Example - Retrieving the lockdiscovery Property .............63
12.9 .............68
13.9 resourcetype Property .........................................64
12.10 source ..........................................69
13.10source Property ..............................................65
12.10.1 ................................................70
13.10.1 Example - A source Property ................................65
12.11 supportedlock ................................70
13.11supportedlock Property .......................................66
12.11.1 .........................................71
13.11.1 Example - Retrieving the supportedlock Property ............66
13 DAV XML PROCESSING INSTRUCTIONS ..................................67 ............71
14 INSTRUCTIONS FOR PROCESSING XML IN DAV ..........................72
15 DAV COMPLIANCE CLASSES ...........................................67
14.1 ..........................................73
15.1 Class 1 .......................................................68
14.2 ........................................................73
15.2 Class 2 .......................................................68
15 INTERNATIONALIZATION CONSIDERATIONS ..............................68 ........................................................73
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16 INTERNATIONALIZATION CONSIDERATIONS .............................73
17 SECURITY CONSIDERATIONS ..........................................69
16.1 .........................................75
17.1 Authentication of Clients .....................................69
16.2 ......................................75
17.2 Denial of Service .............................................70
16.3 ..............................................75
17.3 Security through Obscurity ....................................70
16.4 .....................................76
17.4 Privacy Issues Connected to Locks .............................71
16.5 ..............................76
17.5 Privacy Issues Connected to Properties ........................71
16.6 .........................76
17.6 Reduction of Security due to Source Link ......................71
17 .......................76
17.7 Implications of XML External Entities ..........................77
17.8 Risks Connected with Lock Tokens ...............................77
18 IANA CONSIDERATIONS ..............................................71
18 TERMINOLOGY ......................................................72 .............................................78
19 COPYRIGHT ........................................................73 .......................................................78
20 INTELLECTUAL PROPERTY ............................................73 ...........................................79
21 ACKNOWLEDGEMENTS .................................................74 ................................................80
22 REFERENCES .......................................................75 ......................................................81
22.1 Normative References ..........................................75 ...........................................81
22.2 Informational References ......................................75 .......................................82
23 AUTHORS' ADDRESSES ...............................................77 ..............................................83
24 APPENDICES .......................................................78 ......................................................84
24.1 Appendix 1 - WebDAV Document Type Definition ..................78 ...................84
24.2 Appendix 2 - ISO 8601 Date and Time Profile ...................79 ....................85
24.3 Appendix 3 - Notes on Processing XML Elements .................80 ..................86
24.3.1 Notes on Empty XML Elements .................................80 .................................86
24.3.2 Notes on Illegal XML Processing .............................80 .............................86
24.4 Appendix 4 -- XML Namespaces for WebDAV .......................82
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24.4.1 Introduction ................................................82 ................................................88
24.4.2 Namespace Declaration PI ....................................83 Motivation and Summary ......................................88
24.4.3 Placing Declarations in Documents ...........................84 Declaring Namespaces ........................................89
24.4.4 Prolog with Namespace Declarations ..........................84
24.4.5 Qualified Names .............................................84
24.4.6 Universal Names .............................................85
24.4.7 .............................................90
24.4.5 Using Qualified Names .......................................85 .......................................91
24.4.6 Applying Namespaces to Elements and Attributes ..............92
24.4.7 Uniqueness of Attributes ....................................94
24.4.8 Processing instruction ......................................85 Conformance .................................................95
24.4.9 Scope and Meaning of Qualified Names ........................85 ..................................95
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1 Introduction
This document describes an extension to the HTTP/1.1 protocol that
allows clients to perform remote web content authoring operations.
This extension provides a coherent set of methods, headers, request
entity body formats, and response entity body formats that provide
operations for:
Properties: The ability to create, remove, and query information
about Web pages, such as their authors, creation dates, etc. Also,
the ability to link pages of any media type to related pages.
Collections: The ability to create sets of related documents and to
retrieve a hierarchical membership listing (like a directory listing
in a file system).
Locking: The ability to keep more than one person from working on a
document at the same time. This prevents the "lost update problem,"
in which modifications are lost as first one author then another
writes changes without merging the other author's changes.
Namespace Operations: The ability to instruct the server to copy and
move Web resources.
Requirements and rationale for these operations are described in a
companion document, "Requirements for a Distributed Authoring and
Versioning Protocol for the World Wide Web" [Slein et al., 1998]. [RFC2291].
The sections below provide a detailed introduction to resource
properties (section 3), collections of resources (section 4), 5), and
locking operations (section 5). 6). These sections introduce the
abstractions manipulated by the WebDAV-specific HTTP methods
described in section 7, 8, "HTTP Methods for Distributed Authoring".
In HTTP/1.1, method parameter information was exclusively encoded in
HTTP headers. Unlike HTTP/1.1, WebDAV, WebDAV encodes method parameter
information either in an Extensible Markup Language (XML) [Bray,
Paoli, Sperberg-McQueen, 1998] [REC-XML]
request entity body, or in an HTTP header. The use of XML to encode
method parameters was motivated by the ability to add extra XML
elements to existing structures, providing extensibility, extensibility; and by
XML's ability to encode information in ISO 10646 character sets,
providing internationalization support. As a rule of thumb,
parameters are encoded in XML entity bodies when they have unbounded
length, or when they may be shown to a human user and hence require
encoding in an ISO 10646 character set. Otherwise, parameters are
encoded within HTTP headers. Section 8 9 describes the new HTTP
headers used with WebDAV methods.
In addition to encoding method parameters, XML is used in WebDAV to
encode the responses from methods, providing the extensibility and
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internationalization advantages of XML for method output, as well as
input.
XML elements used in this specification are defined in section 11. 12.
The XML namespace extension (Appendix 4) is also used in this
specification in order to allow for new XML elements to be added
without fear of colliding with other element names.
While the status codes provided by HTTP/1.1 are sufficient to
describe most error conditions encountered by WebDAV methods, there
are some errors that do not fall neatly into the existing
categories. New status codes developed for the WebDAV methods are
defined in section 9. 10. Since some WebDAV methods may operate over
many resources, the Multi-Status response has been introduced to
return status information for multiple resources. The Multi-Status
response is described in section 10. 11.
WebDAV employs the property mechanism to store information about the
current state of the resource. For example, when a lock is taken
out on a resource, a lock information property describes the current
state of the lock. Section 12 13 defines the properties used within the
WebDAV specification.
Finishing off the specification are sections on what it means to be
compliant with this specification (section 14), 15), on
internationalization support (section 15), 16), and on security (section
16).
17).
2 Notational Conventions
Since this document describes a set of extensions to the HTTP/1.1
protocol, the augmented BNF used herein to describe protocol
elements is exactly the same as described in section 2.1 of
[Fielding et al., 1997].
[RFC2068]. Since this augmented BNF uses the basic production rules
provided in section 2.2 of [Fielding et al., 1997], [RFC2068], these rules apply to this
document as well.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [Bradner,
1997]. [RFC2119].
3 Data Model for Resource Properties
3.1 The Resource Property Model
Properties are pieces of data Terminology
URI/URL - As defined in [RFC2396].
Collection - A resource that describe contains member resources and meets the state of a resource.
Properties are data about data.
Properties are used
requirements in distributed authoring environments to provide
for efficient discovery and management section 5 of resources. For example, this specification.
Member Resource - A resource contained by a collection.
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'subject' property might allow for the indexing
Internal Member Resource - A member resource of all resources by
their subject, and an 'author' property might allow for a collection whose
URI is immediately relative to the
discovery of what authors have written which documents.
The DAV property model consists URI of the collection.
Property - A name/value pairs. The name of pair that contains descriptive information
about a resource.
Live Property - A property identifies the property's syntax and semantics, whose semantics and
provides an address by which to refer to its syntax and semantics.
There are two categories of properties: "live" and "dead". A live
property has its syntax and enforced
by the server. For example, the live "getcontentlength" property
has its value, the length of the entity returned by a GET request,
automatically calculated by the server.
Dead Property - A property whose semantics and syntax are not
enforced by the server. The server only records the value of a dead
property; the client is responsible for maintaining the consistency
of the syntax and semantics of a dead property.
Null Resource - A resource which responds with a 404 (Not Found) to
any HTTP/1.1 or DAV method except for PUT, MKCOL, OPTIONS and LOCK.
A NULL resource MUST NOT appear as a member of its parent
collection.
4 Data Model for Resource Properties
4.1 The Resource Property Model
Properties are pieces of data that describe the state of a resource.
Properties are data about data.
Properties are used in distributed authoring environments to provide
for efficient discovery and management of resources. For example, a
'subject' property might allow for the indexing of all resources by
their subject, and an 'author' property might allow for the
discovery of what authors have written which documents.
The DAV property model consists of name/value pairs. The name of a
property identifies the property's syntax and semantics, and
provides an address by which to refer to its syntax and semantics.
There are two categories of properties: "live" and "dead". A live
property has its syntax and semantics enforced by the server. Live
properties include cases where a) the value of a property is read-
only, maintained by the server, and b) the value of the property is
maintained by the client, but the server performs syntax checking on
submitted values. All instances of a given live property MUST comply
with the definition associated with that property name. A dead
property has its syntax and semantics enforced by the client; the
server merely records the value of the property verbatim.
3.2
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4.2 Existing Metadata Proposals
Properties have long played an essential role in the maintenance of
large document repositories, and many current proposals contain some
notion of a property, or discuss web metadata more generally. These
include PICS [Miller et al., 1996], [REC-PICS], PICS-NG, XML, Web Collections, and several
proposals on representing relationships within HTML. Work on PICS-NG
and Web Collections has been subsumed by the Resource Definition
Framework (RDF) metadata activity of the World Wide Web Consortium.
RDF consists of a network-based data model and an XML representation
of that model.
Some proposals come from a digital library perspective. These
include the Dublin Core [Weibel et al., 1995] [RFC2413] metadata set and the Warwick
Framework [Lagoze, 1996], a container architecture for different
metadata schemas. The literature includes many examples of
metadata, including MARC [MARC, 1994], [USMARC], a bibliographic metadata format,
and RFC 1807 [Lasher, Cohen, 1995], a technical report bibliographic format employed by the Dienst system.
system [RFC1807]. Additionally, the proceedings from the first IEEE
Metadata conference describe many community-specific metadata sets.
Participants of the 1996 Metadata II Workshop in Warwick, UK
[Lagoze, 1996], noted that "new metadata sets will develop as the
networked infrastructure matures" and "different communities will
propose, design, and be responsible for different types of
metadata." These observations can be corroborated by noting that
many community-specific sets of metadata already exist, and there is
significant motivation for the development of new forms of metadata
as many communities increasingly make their data available in
digital form, requiring a metadata format to assist data location
and cataloging.
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3.3
4.3 Properties and HTTP Headers
Properties already exist, in a limited sense, in HTTP message
headers. However, in distributed authoring environments a
relatively large number of properties are needed to describe the
state of a resource, and setting/returning them all through HTTP
headers is inefficient. Thus a mechanism is needed which allows a
principal to identify a set of properties in which the principal is
interested and to set or retrieve just those properties.
3.4
4.4 Property Values
The value of a property is, at minimum, when expressed in XML MUST be well formed XML. formed.
XML has been chosen because it is a flexible, self-describing,
structured data format that supports rich schema definitions, and
because of its support for multiple character sets. XML's self-
describing nature allows any property's value to be extended by
adding new elements. Older clients will not break when they
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encounter extensions because they will still have the data specified
in the original schema and will ignore elements they do not
understand. XML's support for multiple character sets allows any
human-readable property to be encoded and read in a character set
familiar to the user.
3.5 XML's support for multiple human languages,
using the "xml:lang" attribute, handles cases where the same
character set is employed by multiple human languages.
4.5 Property Names
A property name is a universally unique identifier that is
associated with a schema that provides information about the syntax
and semantics of the property.
Because a property's name is universally unique, clients can depend
upon consistent behavior for a particular property across multiple
resources, on the same and across different servers, so long as that
property is "live" on the resources in
question. question, and the
implementation of the live property is faithful to its definition.
The XML namespace mechanism, which is based on URIs, URIs [RFC2396], is
used to name properties because it prevents namespace collisions and
provides for varying degrees of administrative control.
The property namespace is flat; that is, no hierarchy of properties
is explicitly recognized. Thus, if a property A and a property A/B
exist on a resource, there is no recognition of any relationship
between the two properties. It is expected that a separate
specification will eventually be produced which will address issues
relating to hierarchical properties.
Finally, it is not possible to define the same property twice on a
single resource, as this would cause a collision in the resource's
property namespace.
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3.6
4.6 Media Independent Links
Although HTML resources support links to other resources, the Web
needs more general support for links between resources of any media
type. WebDAV provides such links. A WebDAV link is a special type
of property value, formally defined in section 11.4, 12.4, that allows
typed connections to be established between resources of any media
type. The property value consists of source and destination Uniform
Resource Locators (URLs); the property name identifies the link
type.
4
5 Collections of Web Resources
This section provides a description of a new type of Web resource,
the collection, and discusses its interactions with the HTTP URL
namespace. The purpose of a collection resource is to model
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collection-like objects (e.g., file system directories) within a
server's namespace.
All DAV compliant resources MUST support the HTTP URL namespace
model specified herein.
4.1
5.1 HTTP URL Namespace Model
The HTTP URL namespace is a hierarchical namespace where the
hierarchy is delimited with the "/" character.
An HTTP URL namespace is said to be consistent if it meets the
following rule: for every non-null resource A, there exists a non-
null resource B that is a collection and has resource A as an
internal member. The root of the namespace is exempt from the
previous rule.
Neither HTTP/1.1 nor WebDAV require that the entire HTTP URL
namespace be consistent. However, certain WebDAV methods are
prohibited from producing results that cause namespace
inconsistencies.
5.2 Collection Resources
A collection is a resource whose state consists of at least a list
of internal members and a set of properties, but which may have
additional state such as entity bodies returned by GET. An internal
member resource MUST have a URI that is immediately relative to the
base URI of the collection. That is, the internal member's URI is
equal to the parent collection's URI plus an additional segment
where segment is defined in section 3.2.1 of RFC 2068 [Fielding et
al., 1996].
Any given internal member MUST only belong to the collection once,
i.e., it is illegal to have multiple instances of the same URI in a
collection. Properties defined on collections behave exactly as do
properties on non-collection resources.
For all WebDAV servers MUST treat HTTP URL namespaces as collections,
regardless of whether they were created with compliant resources A and B for which B is the MKCOL method
described parent
of A in section 7.3.
There is a standing convention that when the HTTP URL namespace hierarchy, B MUST be a collection
which has A as an internal member. So, if http://foo.com/bar/blah is referred to
by its name without a trailing slash, the trailing slash
WebDAV compliant and if http://foo.com/bar/ is
automatically WebDAV compliant then
http://foo.com/bar/ must be a collection and must contain
http://foo.com/bar/blah as an internal member.
Collection resources MAY list their non-WebDAV compliant children in
the HTTP URL namespace hierarchy as internal members but are not
required to do so. For example, if http://foo.com/bar/blah is not
WebDAV compliant and http://foo.com/bar/ is a collection then
http://foo.com/bar/blah may or may not be listed as an internal
member of http://foo.com/bar/.
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If a WebDAV compliant resource has no WebDAV compliant children in
the HTTP URL namespace hierarchy then the WebDAV compliant resource
is not required to be a collection.
There is a standing convention that when a collection is referred to
by its name without a trailing slash, the trailing slash is
automatically appended. Due to this, a resource may accept a URI
without a trailing "/" to point to a collection. In this case it
SHOULD return a content-location header in the response pointing to
the URL ending with the "/". For example, if a client invokes a
method on http://foo.bar/blah (no trailing slash), the resource
http://foo.bar/blah/ (trailing slash) may respond as if the
operation were invoked on it, and should return a content-location
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header with http://foo.bar/blah/ in it. In general clients SHOULD
use the "/" form of collection names.
4.2
A resource MAY be a collection but not be WebDAV compliant. That
is, the resource may comply with all the rules set out in this
specification regarding how a collection is to behave without
necessarily supporting all methods that a WebDAV compliant resource
is required to support. In such a case the resource may return the
dav:resourcetype property with the value dav:collection but MUST NOT
return a DAV header containing the value "1" on an OPTIONS response.
5.3 Creation and Retrieval of Collection Resources
This document specifies the MKCOL method to create new collection
resources, rather than using the existing HTTP/1.1 PUT or POST
method, for the following reasons:
In HTTP/1.1, the PUT method is defined to store the request body at
the location specified by the Request-URI. While a description
format for a collection can readily be constructed for use with PUT,
the implications of sending such a description to the server are
undesirable. For example, if a description of a collection that
omitted some existing resources were PUT to a server, this might be
interpreted as a command to remove those members. This would extend
PUT to perform DELETE functionality, which is undesirable since it
changes the semantics of PUT, and makes it difficult to control
DELETE functionality with an access control scheme based on methods.
While the POST method is sufficiently open-ended that a "create a
collection" POST command could be constructed, this is undesirable
because it would be difficult to separate access control for
collection creation from other uses of POST.
The exact definition of the behavior of GET and PUT on collections
is defined later in this document.
4.3 HTTP URL Namespace Model
The HTTP URL Namespace is a hierarchical namespace where the
hierarchy is delimited with
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5.4 Source Resources and Output Resources
For many resources, the "/" character. DAV compliant
resources MUST maintain entity returned by a GET method exactly
matches the consistency of the HTTP URL namespace.
For example, if the collection http://www.foo.bar.org/a/ exists, but
http://www.foo.bar.org/a/b/ does not exist, an attempt to create
http://www.foo.bar.org/a/b/c must fail.
4.4 Source Resources and Output Resources
For many resources, the entity returned by a GET method exactly
matches the persistent state persistent state of the resource, for example, a GIF
file stored on a disk. For this simple case, the URL at which a
resource is accessed is identical to the URL at which the source
(the persistent state) of the resource is accessed. This is also
the case for HTML source files that are not processed by the server
prior to transmission.
However, the server can sometimes process HTML resources before they
are transmitted as a return entity body. For example, a server-
side-include directive within an HTML file might instruct a server
to replace the directive with another value, such as the current
date. In this case, what is returned by GET (HTML plus date)
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differs from the persistent state of the resource (HTML plus
directive). Typically there is no way to access the HTML resource
containing the unprocessed directive.
Sometimes the entity returned by GET is the output of a data-
producing process that is described by one or more source resources
(that may not even have a location in the URL namespace). A single
data-producing process may dynamically generate the state of a
potentially large number of output resources. An example of this is
a CGI script that describes a "finger" gateway process that maps
part of the namespace of a server into finger requests, such as
http://www.foo.bar.org/finger_gateway/user@host.
In the absence of distributed authoring capabilities, it is
acceptable to have no mapping of source resource(s) to the URI
namespace. In fact, preventing access to the source resource(s) has
desirable security benefits. However, if remote editing of the
source resource(s) is desired, the source resource(s) should be
given a location in the URI namespace. This source location should
not be one of the locations at which the generated output is
retrievable, since in general it is impossible for the server to
differentiate requests for source resources from requests for
process output resources. There is often a many-to-many
relationship between source resources and output resources.
On WebDAV compliant servers the URI of the source resource(s) may be
stored in a link on the output resource with type DAV:source (see
section 12.10 13.10 for a description of the source link property).
Storing the source URIs in links on the output resources places the
burden of discovering the source on the authoring client. Note that
the value of a source link is not guaranteed to point to the correct
source. Source links may break or incorrect values may be entered.
Also note that not all servers will allow the client to set the
source link value. For example a server which generates source
links on the fly for its CGI files will most likely not allow a
client to set the source link value.
5
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6 Locking
The ability to lock a resource provides a mechanism for serializing
access to that resource. Using a lock, an authoring client can
provide a reasonable guarantee that another principal will not
modify a resource while it is being edited. In this way, a client
can prevent the "lost update" problem.
This specification allows locks to vary over two client-specified
parameters, the number of principals involved (exclusive vs. shared)
and the type of access to be granted. This document defines locking
for only one access type, write. However, the syntax is extensible,
and permits the eventual specification of locking for other access
types.
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5.1
6.1 Exclusive Vs. Shared Locks
The most basic form of lock is an exclusive lock. This is a lock
where the access right in question is only granted to a single
principal. The need for this arbitration results from a desire to
avoid having to merge results.
However, there are times when the goal of a lock is not to exclude
others from exercising an access right but rather to provide a
mechanism for principals to indicate that they intend to exercise
their access rights. Shared locks are provided for this case. A
shared lock allows multiple principals to receive a lock. Hence any
principal with appropriate access can get the lock.
With shared locks there are two trust sets that affect a resource.
The first trust set is created by access permissions. Principals
who are trusted, for example, may have permission to write to the
resource. Among those who have access permission to write to the
resource, the set of principals who have taken out a shared lock
also must trust each other, creating a (typically) smaller trust set
within the access permission write set.
Starting with every possible principal on the Internet, in most
situations the vast majority of these principals will not have write
access to a given resource. Of the small number who do have write
access, some principals may decide to guarantee their edits are free
from overwrite conflicts by using exclusive write locks. Others may
decide they trust their collaborators will not overwrite their work
(the potential set of collaborators being the set of principals who
have write permission) and use a shared lock, which informs their
collaborators that a principal may be working on the resource.
The WebDAV extensions to HTTP do not need to provide all of the
communications paths necessary for principals to coordinate their
activities. When using shared locks, principals may use any out of
band communication channel to coordinate their work (e.g., face-to-
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face interaction, written notes, post-it notes on the screen,
telephone conversation, Email, etc.) The intent of a shared lock is
to let collaborators know who else may be working on a resource.
Shared locks are included because experience from web distributed
authoring systems has indicated that exclusive locks are often too
rigid. An exclusive lock is used to enforce a particular editing
process: take out an exclusive lock, read the resource, perform
edits, write the resource, release the lock. This editing process
has the problem that locks are not always properly released, for
example when a program crashes, or when a lock owner leaves without
unlocking a resource. While both timeouts and administrative action
can be used to remove an offending lock, neither mechanism may be
available when needed; the timeout may be long or the administrator
may not be available.
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5.2
6.2 Required Support
A WebDAV compliant server is not required to support locking in any
form. If the server does support locking it may choose to support
any combination of exclusive and shared locks for any access types.
The reason for this flexibility is that locking policy strikes to
the very heart of the resource management and versioning systems
employed by various storage repositories. These repositories
require control over what sort of locking will be made available.
For example, some repositories only support shared write locks while
others only provide support for exclusive write locks while yet
others use no locking at all. As each system is sufficiently
different to merit exclusion of certain locking features, this
specification leaves locking as the sole axis of negotiation within
WebDAV.
5.3
6.3 Lock Tokens
A lock token is a type of state token, represented as a URI, which
identifies a particular lock. A lock token is returned by every
successful LOCK operation in the lockdiscovery property in the
response body, and can also be found through lock discovery on a
resource.
Lock token URIs MUST be unique across all resources for all time.
This uniqueness constraint allows lock tokens to be submitted across
resources and servers without fear of confusion.
This specification provides a lock token URI scheme called
opaquelocktoken that meets the uniqueness requirements. However
resources are free to return any URI scheme so long as it meets the
uniqueness requirements.
Having a lock token provides no special access rights. Anyone can
find out anyone else's lock token by performing lock discovery.
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Locks MUST be enforced based upon whatever authentication mechanism
is used by the server, not based on the secrecy of the token values.
5.4
6.4 opaquelocktoken Lock Token URI Scheme
The opaquelocktoken URI scheme is designed to be unique across all
resources for all time. Due to this uniqueness quality, a client
may submit an opaque lock token in an If header on a resource other
than the one that returned it.
All resources MUST recognize the opaquelocktoken scheme and, at
minimum, recognize that the lock token does not refer to an
outstanding lock on the resource.
In order to guarantee uniqueness across all resources for all time
the opaquelocktoken requires the use of the Universally Unique
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Identifier (UUID, also known as a Globally Unique Identifier, or
GUID) globally unique
identifier (GUID) mechanism, as described in [Leach, Salz, 1998]. [ISO-11578].
Opaquelocktoken generators, however, have a choice of how they
create these tokens. They can either generate a new UUID GUID for every
lock token they create or they can create a single UUID GUID and then
add extension characters. If the second method is selected then the
program generating the extensions MUST guarantee that the same
extension will never be used twice with the associated UUID. GUID.
OpaqueLockToken-URI = "opaquelocktoken:" UUID GUID [Extension] ; The
UUID
GUID production is the string form representation of a UUID, GUID, as defined
in [Leach,
Salz, 1998]. [ISO-11578]. Note that white space (LWS) is not allowed between
elements of this production.
Extension = path ; path is defined in section 3.2.1 of RFC 2068
[Fielding et al., 1996]
5.5 Lock Capability Discovery
Since server lock support is optional, a client trying to lock a
resource on
6.4.1 Node Field Generation Without the IEEE 802 Address
GUIDs, as defined in [ISO-11578], contain a "node" field which
contains one of the IEEE 802 addresses for the server can either try machine. As
noted in section 17.8, there are several security risks associated
with exposing a machine's IEEE 802 address. This section provides an
alternate mechanism for generating the lock and hope "node" field of a GUID which
does not employ an IEEE 802 address. WebDAV servers MAY use this
algorithm for creating the best,
or perform some form node field when generating GUIDs. The
text in this section is quoted from section 4 of discovery draft-leach-uuids-
guids-01 (expired).
The ideal solution is to determine what lock
capabilities obtain a 47 bit cryptographic quality
random number, and use it as the server supports. low 47 bits of the node ID, with
the most significant bit of the first octet of the node ID set to 1.
This bit is known as lock capability
discovery. Lock capability discovery differs the unicast/multicast bit, which will never be set in
IEEE 802 addresses obtained from discovery of
supported access control types, since network cards; hence, there may be access control
types without corresponding lock types. A client can determine what
lock types the server supports by retrieving the supportedlock
property.
Any DAV compliant resource that supports the LOCK method MUST
support the supportedlock property.
5.6 Active Lock Discovery
If another principal locks a resource that a principal wishes to
access, it is useful for the second principal to be able to find out
who the first principal is. For this purpose the lockdiscovery
property is provided. This property lists all outstanding locks,
describes their type, and where available, provides their lock
token.
Any DAV compliant resource that supports the LOCK method MUST
support the lockdiscovery property.
5.7 Usage Considerations
Although the locking mechanisms specified here provide some help in
preventing lost updates, they cannot guarantee that updates will
never be lost. Consider the following scenario: a conflict between GUIDs generated by machines with and
without network cards.
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Two clients A and B are interested in editing the resource
'index.html'. Client A is an HTTP client rather than
If a WebDAV
client, and so system does not know how to perform locking.
Client A doesn't lock the document, but does a GET and begins
editing.
Client B does LOCK, performs a GET and begins editing.
Client B finishes editing, performs have a PUT, primitive to generate cryptographic
quality random numbers, then an UNLOCK.
Client A performs in most systems there are usually a PUT, overwriting and losing all
fairly large number of B's changes.
There sources of randomness available from which
one can be generated. Such sources are several reasons why system specific, but often
include:
- the WebDAV protocol itself cannot
prevent this situation. First, it cannot force all clients to percent of memory in use
locking because it must be compatible with HTTP clients that do not
comprehend locking. Second, it cannot require servers to support
locking because
- the size of main memory in bytes
- the variety amount of repository implementations, some free main memory in bytes
- the size of which rely the paging or swap file in bytes
- free bytes of paging or swap file
- the total size of user virtual address space in bytes
- the total available user address space bytes
- the size of boot disk drive in bytes
- the free disk space on reservations boot drive in bytes
- the current time
- the amount of time since the system booted
- the individual sizes of files in various system directories
- the creation, last read, and merging rather than on locking.
Finally, being stateless, it cannot enforce a sequence modification times of operations
like LOCK / GET / PUT / UNLOCK.
WebDAV servers files in
various system directories
- the utilization factors of various system resources (heap, etc.)
- current mouse cursor position
- current caret position
- current number of running processes, threads
- handles or IDs of the desktop window and the active window
- the value of stack pointer of the caller
- the process and thread ID of caller
- various processor architecture specific performance counters
(instructions executed, cache misses, TLB misses)
(Note that support locking can reduce it is precisely the likelihood above kinds of sources of randomness
that
clients will accidentally overwrite each other's changes by
requiring clients are used to lock resources before modifying them. Such
servers would effectively prevent HTTP 1.0 seed cryptographic quality random number generators
on systems without special hardware for their construction.)
In addition, items such as the computer's name and HTTP 1.1 clients the name of the
operating system, while not strictly speaking random, will help
differentiate the results from
modifying resources.
WebDAV clients can be good citizens those obtained by using a lock / retrieve /
write /unlock sequence of operations (at least by default) whenever
they interact with a WebDAV server that supports locking.
HTTP 1.1 clients can be good citizens, avoiding overwriting other
clients' changes, by using entity tags in If-Match headers with any
requests that would modify resources.
Information managers may attempt systems.
The exact algorithm to prevent overwrites by
implementing client-side procedures requiring locking before
modifying WebDAV resources.
6 Write Lock
This section describes generate a node ID using these data is system
specific, because both the semantics specific data available and the functions to
obtain them are often very system specific. However, assuming that
one can concatenate all the write lock
type. The write lock is a specific instance of values from the randomness sources into
a lock type, buffer, and that a cryptographic hash function such as MD5 is
available, then any 6 bytes of the only lock type described in this specification.
6.1 Methods Restricted by Write Locks
A write lock MUST prevent a principal without MD5 hash of the lock from
successfully executing a PUT, POST, PROPPATCH, LOCK, UNLOCK, MOVE,
DELETE, or MKCOL on buffer, with the locked resource. All other current methods,
GET in particular, function independent
multicast bit (the high bit of the lock.
Note, however, that as new methods are created it first byte) set will be necessary
to specify how they interact with an
appropriately random node ID.
Other hash functions, such as SHA-1, can also be used. The only
requirement is that the result be suitably random _ in the sense
that the outputs from a write lock. set uniformly distributed inputs are
themselves uniformly distributed, and that a single bit change in
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6.2 Write Locks and Properties
While those without a write lock may not alter a property on a
resource it is still possible for
the values of live properties to
change, even while locked, due input can be expected to the requirements cause half of their schemas.
Only dead properties and live properties defined to respect locks
are guaranteed not the output bits to change while write locked.
6.3 Write Locks and Null Resources
It
change.
6.5 Lock Capability Discovery
Since server lock support is possible to assert optional, a write client trying to lock on a null
resource in order to on a server can either try the lock and hope for the name.
A write locked null resource, referred to as a lock-null resource,
MUST respond with a 404 Not Found best,
or 405 Method Not Allowed perform some form of discovery to any
HTTP/1.1 or DAV methods except for PUT, MKCOL, OPTIONS, PROPFIND,
LOCK, and UNLOCK. A lock-null resource MUST appear determine what lock
capabilities the server supports. This is known as a member lock capability
discovery. Lock capability discovery differs from discovery of
its parent collection. Additionally
supported access control types, since there may be access control
types without corresponding lock types. A client can determine what
lock types the lock-null resource MUST
have defined on it all mandatory DAV properties. Most of these
properties, such as all server supports by retrieving the get* properties, will have no value as a
lock-null supportedlock
property.
Any DAV compliant resource does not support that supports the GET method. Lock-Null
resources LOCK method MUST have defined values for lockdiscovery and
support the supportedlock properties.
Until property.
6.6 Active Lock Discovery
If another principal locks a method such as PUT or MKCOL resource that a principal wishes to
access, it is successfully executed on useful for the
lock-null resource second principal to be able to find out
who the resource MUST stay in first principal is. For this purpose the lock-null state.
However, once a PUT or MKCOL lockdiscovery
property is successfully executed on a lock-null provided. This property lists all outstanding locks,
describes their type, and where available, provides their lock
token.
Any DAV compliant resource that supports the resources ceases to be LOCK method MUST
support the lockdiscovery property.
6.7 Usage Considerations
Although the locking mechanisms specified here provide some help in
preventing lost updates, they cannot guarantee that updates will
never be lost. Consider the lock-null state.
If following scenario:
Two clients A and B are interested in editing the resource
'index.html'. Client A is unlocked, for any reason, without an HTTP client rather than a PUT, MKCOL,
or similar method having been successfully executed upon it then the
resource MUST return to the null state.
6.4 Write Locks WebDAV
client, and Collections so does not know how to perform locking.
Client A write doesn't lock on a collection prevents the addition or removal of
members of the collection by non-lock owners. As a consequence,
when a principal issues document, but does a request to create GET and begins
editing.
Client B does LOCK, performs a new internal member of GET and begins editing.
Client B finishes editing, performs a write locked collection using PUT or POST, or to remove PUT, then an
existing internal member of UNLOCK.
Client A performs a write locked collection using DELETE,
this request MUST fail if PUT, overwriting and losing all of B's changes.
There are several reasons why the principal does not have a write lock
on the collection.
However, if a write lock request is issued WebDAV protocol itself cannot
prevent this situation. First, it cannot force all clients to a collection
containing internal member resources that are currently locked in a
manner which conflicts with the write lock, the request MUST fail use
locking because it must be compatible with a 423 Locked status code.
If a lock owner causes a resource HTTP clients that do not
comprehend locking. Second, it cannot require servers to be added as an internal member support
locking because of a locked collection then the new resource MUST be automatically
added to the lock. This is the only mechanism that allows a variety of repository implementations, some
of which rely on reservations and merging rather than on locking.
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resource to be added to
Finally, being stateless, it cannot enforce a write lock. Thus, for example, if the
collection /a/b/ is write locked and sequence of operations
like LOCK / GET / PUT / UNLOCK.
WebDAV servers that support locking can reduce the resource /c is moved to
/a/b/c then /a/b/c likelihood that
clients will be added accidentally overwrite each other's changes by
requiring clients to the write lock.
6.5 Write Locks lock resources before modifying them. Such
servers would effectively prevent HTTP 1.0 and the If Request Header
If a user agent is not required to have knowledge about HTTP 1.1 clients from
modifying resources.
WebDAV clients can be good citizens by using a lock when
requesting an operation on a locked resource, the following scenario
might occur. Program A, run by User A, takes out / retrieve /
write /unlock sequence of operations (at least by default) whenever
they interact with a WebDAV server that supports locking.
HTTP 1.1 clients can be good citizens, avoiding overwriting other
clients' changes, by using entity tags in If-Match headers with any
requests that would modify resources.
Information managers may attempt to prevent overwrites by
implementing client-side procedures requiring locking before
modifying WebDAV resources.
7 Write Lock
This section describes the semantics specific to the write lock on
type. The write lock is a
resource. Program B, also run by User A, has no knowledge specific instance of a lock type, and is
the only lock taken out type described in this specification.
7.1 Methods Restricted by Program A, yet performs Write Locks
A write lock MUST prevent a PUT to principal without the lock from
successfully executing a PUT, POST, PROPPATCH, LOCK, UNLOCK, MOVE,
DELETE, or MKCOL on the locked resource. In this scenario, All other current methods,
GET in particular, function independently of the PUT succeeds because locks lock.
Note, however, that as new methods are
associated created it will be necessary
to specify how they interact with a principal, not a program, write lock.
7.2 Write Locks and thus program B,
because it is acting with principal A's credential, is allowed to
perform Lock Tokens
A successful request for an exclusive or shared write lock MUST
result in the PUT. However, had program B known about generation of a unique lock token associated with the lock, it
would not
requesting principal. Thus if five principals have overwritten the resource, preferring instead to
present a dialog box describing the conflict to the user. Due to
this scenario, a mechanism is needed to prevent different programs
from accidentally ignoring locks taken out by other programs with shared write
lock on the same authorization.
In order to prevent these collisions a lock token MUST be submitted
by an authorized principal in the If header for all locked resources
that a method may interact with or the method MUST fail. For
example, if a resource is to there will be moved and both the source and
destination are locked then two five lock tokens must be submitted, tokens, one for the source and the other for the destination.
6.5.1 Example -
each principal.
7.3 Write Lock
>>Request
COPY /~fielding/index.html HTTP/1.1
Host: www.ics.uci.edu
Destination: http://www.ics.uci.edu/users/f/fielding/index.html
If: <http://www.ics.uci.edu/users/f/fielding/index.html>
(<opaquelocktoken:f81d4fae-7dec-11d0-a765-00a0c91e6bf6>)
>>Response
HTTP/1.1 204 No Content
In this example, even though both the source Locks and destination are
locked, only one lock token must be submitted, for the Properties
While those without a write lock on the
destination. This is because the source resource is may not modified by alter a COPY, and hence unaffected by the write lock. In this example,
user agent authentication has previously occurred via property on a mechanism
outside
resource it is still possible for the scope values of live properties to
change, even while locked, due to the HTTP protocol, in the underlying transport
layer. requirements of their schemas.
Goland et al. [Page 19] 20]
INTERNET-DRAFT WebDAV April 7, October 22, 1998
6.6
Only dead properties and live properties defined to respect locks
are guaranteed not to change while write locked.
7.4 Write Locks and COPY/MOVE
A COPY method invocation MUST NOT duplicate any Null Resources
It is possible to assert a write locks active lock on a null resource in order to
lock the source. However, name.
A write locked null resource, referred to as previously noted, if a lock-null resource,
MUST respond with a 404 (Not Found) or 405 (Method Not Allowed) to
any HTTP/1.1 or DAV methods except for PUT, MKCOL, OPTIONS,
PROPFIND, LOCK, and UNLOCK. A lock-null resource MUST appear as a
member of its parent collection. Additionally the COPY copies lock-null
resource MUST have defined on it all mandatory DAV properties. Most
of these properties, such as all the get* properties, will have no
value as a lock-null resource into does not support the GET method.
Lock-Null resources MUST have defined values for lockdiscovery and
supportedlock properties.
Until a collection that method such as PUT or MKCOL is depth locked then successfully executed on the
lock-null resource
will be added to the lock.
A MOVE resource MUST NOT move the write lock with stay in the lock-null state.
However, once a PUT or MKCOL is successfully executed on a lock-null
resource although the resource is subject to being added ceases to an existing lock as specified be in section 6.4. For example, if the MOVE makes lock-null state.
If the resource a child
of a collection that is depth locked unlocked, for any reason, without a PUT, MKCOL,
or similar method having been successfully executed upon it then the
resource will be under
that collection's lock. Additionally, if a depth locked resource is
moved MUST return to a destination that is within the scope of the same depth null state.
7.5 Write Locks and Collections
A write lock (e.g., within the namespace tree covered on a collection, whether created by the lock), the
moved resource will again be a member of "Depth: 0" or
"Depth: infinity" lock request, prevents the lock. In both these
examples, as specified in section 6.5, addition or removal of
members of the collection by non-lock owners. As a consequence,
when a principal issues a request to create a new internal member of
a write locked collection using PUT or POST, or to remove an If header must be
submitted containing
existing internal member of a lock token for both the source and
destination.
6.7 Refreshing Write Locks
A client write locked collection using DELETE,
this request MUST NOT submit fail if the same principal does not have a write lock request twice. Note
that a client is always aware it is resubmitting
on the same collection.
However, if a write lock request because it must include the lock token is issued to a collection
containing internal member resources that are currently locked in a
manner which conflicts with the If header in
order to make write lock, the request for MUST fail
with a resource that is already locked.
However, 423 (Locked) status code.
If a client may submit lock owner causes a LOCK method with resource to be added as an If header but
without a body. This form internal member
of LOCK a locked collection then the new resource MUST only be used automatically
added to "refresh" a the lock. Meaning, at minimum, that any timers associated with This is the lock
MUST be re-set.
A server may return only mechanism that allows a Timeout header with
resource to be added to a lock refresh that write lock. Thus, for example, if the
collection /a/b/ is
different than write locked and the Timeout header returned when resource /c is moved to
/a/b/c then /a/b/c will be added to the lock was
originally requested. Additionally clients may submit Timeout
headers of arbitrary value with their lock refresh requests.
Servers, as always, may ignore Timeout headers submitted by write lock.
Goland et al. [Page 21]
INTERNET-DRAFT WebDAV October 22, 1998
7.6 Write Locks and the
client. If an error Request Header
If a user agent is received in response not required to have knowledge about a refresh LOCK request the
client SHOULD assume that the lock was not refreshed.
7 HTTP Methods for Distributed Authoring
The when
requesting an operation on a locked resource, the following new HTTP methods use XML as scenario
might occur. Program A, run by User A, takes out a request and response
format. All DAV compliant clients and resources MUST use XML
parsers that are compliant with [Bray, Paoli, Sperberg-McQueen,
1998]. All XML used in either requests or responses MUST be, at
minimum, well formed. If write lock on a server receives ill-formed XML in
resource. Program B, also run by User A, has no knowledge of the
lock taken out by Program A, yet performs a
request it MUST reject PUT to the entire request locked
resource. In this scenario, the PUT succeeds because locks are
associated with a 400 Bad Request.
If a client receives ill-formed XML in principal, not a response then program, and thus program B,
because it MUST NOT
assume anything is acting with principal A's credential, is allowed to
perform the PUT. However, had program B known about the outcome of lock, it
would not have overwritten the executed method and SHOULD
treat resource, preferring instead to
present a dialog box describing the server as malfunctioning.
Goland et al. [Page 20]
INTERNET-DRAFT WebDAV April 7, 1998
7.1 PROPFIND
The PROPFIND method retrieves properties defined on the Request-URI,
if the resource does not have any internal members, or on conflict to the
Request-URI and potentially its member resources, if user. Due to
this scenario, a mechanism is needed to prevent different programs
from accidentally ignoring locks taken out by other programs with
the resource
does have internal members. All DAV compliant resources same authorization.
In order to prevent these collisions a lock token MUST
support the PROPFIND method and be submitted
by an authorized principal in the propfind XML element (section
11.14) along with all XML elements defined If header for use with all locked resources
that
element.
A client may submit a Depth header method may interact with a value of "0", "1", or
"infinity" with a PROPFIND on a resource with internal members. DAV
compliant servers MUST support the "0", "1" and "infinity"
behaviors. By default, the PROPFIND method without a Depth header MUST act as fail. For
example, if a "Depth: infinity" header was included.
A client may submit a propfind XML element in the body of the
request method describing what information is being requested. It resource is possible to request particular property values, all property
values, or a list of the names of be moved and both the resource's properties. A
client may choose not to submit a request body. An empty PROPFIND
request body MUST source and
destination are locked then two lock tokens must be treated as a request submitted, one
for the names source and values
of all properties.
All servers MUST support returning a response of content type
text/xml that contains a multistatus XML element that describes the
results of other for the attempts to retrieve destination.
7.6.1 Example - Write Lock
>>Request
COPY /~fielding/index.html HTTP/1.1
Host: www.ics.uci.edu
Destination: http://www.ics.uci.edu/users/f/fielding/index.html
If: <http://www.ics.uci.edu/users/f/fielding/index.html>
(<opaquelocktoken:f81d4fae-7dec-11d0-a765-00a0c91e6bf6>)
>>Response
HTTP/1.1 204 No Content
In this example, even though both the various properties.
If there source and destination are
locked, only one lock token must be submitted, for the lock on the
destination. This is an error retrieving a property then because the source resource is not modified by
a proper error
result MUST be included in COPY, and hence unaffected by the response. A request to retrieve write lock. In this example,
user agent authentication has previously occurred via a mechanism
outside the
value scope of a property which does not exist is an error the HTTP protocol, in the underlying transport
layer.
7.7 Write Locks and COPY/MOVE
A COPY method invocation MUST be NOT duplicate any write locks active
on the source. However, as previously noted, if the response uses a multistatus XML element, with a
response XML element which contains a 404 Not Found status value.
Consequently, COPY copies the multistatus XML element for a
Goland et al. [Page 22]
INTERNET-DRAFT WebDAV October 22, 1998
resource with
members MUST include into a response XML element for each member of the
resource, to whatever depth was requested. Each response XML element
MUST contain an href XML element collection that identifies is locked with "Depth: infinity",
then the resource on
which the properties in will be added to the prop XML element are defined. Results
for a PROPFIND lock.
A successful MOVE request on a write locked resource MUST NOT move
the write lock with internal members are returned as a
flat list whose order of entries the resource. However, the resource is not significant.
In subject
to being added to an existing lock at the case of allprop and propname, destination, as specified
in section 7.5. For example, if a principal does not have the right to know whether MOVE makes the resource a particular property exists child
of a collection that is locked with "Depth: infinity", then the
property should be silently excluded from the response.
The results of this method SHOULD NOT
resource will be cached.
Goland et al. [Page 21]
INTERNET-DRAFT WebDAV April 7, 1998
7.1.1 Example - Retrieving Named Properties
>>Request
PROPFIND /file HTTP/1.1
Host: www.foo.bar
Content-type: text/xml
Content-Length: xyz
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.foo.bar/boxschema/" prefix="R" ?>
<D:propfind>
<D:prop>
<R:bigbox/>
<R:author/>
<R:DingALing/>
<R:Random/>
</D:prop>
</D:propfind>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml
Content-Length: xxxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.foo.bar/boxschema/" prefix="R" ?>
<D:multistatus>
<D:response>
<D:href>http://www.foo.bar/file</D:href>
<D:propstat>
<D:prop>
<R:bigbox>
<R:BoxType>Box type A</R:BoxType>
</R:bigbox>
<R:author>
<R:Name>J.J. Johnson</R:Name>
</R:author>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
<D:propstat>
<D:prop><R:DingALing/><R:Random/></D:prop>
<D:status>HTTP/1.1 403 Forbidden</D:status>
<D:responsedescription> The user does not have access added to
the DingALing property.
</D:responsedescription>
</D:propstat>
</D:response>
Goland et al. [Page 22]
INTERNET-DRAFT WebDAV April 7, 1998
<D:responsedescription> There has been an access violation error.
</D:responsedescription>
</D:multistatus>
In this example, PROPFIND is executed on that collection's lock. Additionally, if a non-collection
resource
http://www.foo.bar/file. The propfind XML element specifies locked with "Depth: infinity" is moved to a destination
that is within the
name scope of four properties whose values are being requested. In this
case only two properties were returned, since the principal issuing same lock (e.g., within the request did not have sufficient access rights
namespace tree covered by the lock), the moved resource will again
be a added to see the third
and fourth properties.
7.1.2 Example - Using allprop to Retrieve All Properties
>>Request
PROPFIND /container/ HTTP/1.1
Host: www.foo.bar
Depth: 1
Content-Type: text/xml
Content-Length: xxxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:propfind>
<D:allprop/>
</D:propfind>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml
Content-Length: xxxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.foo.bar/boxschema/" prefix="R" ?>
<D:multistatus>
<D:response>
<D:href>http://www.foo.bar/container/</D:href>
<D:propstat>
<D:prop>
<R:bigbox>
<R:BoxType>Box type A</R:BoxType>
</R:bigbox>
<R:author>
<R:Name>Hadrian</R:Name>
</R:author>
<D:creationdate>
1997-12-01T17:42:21-08:00
</D:creationdate>
<D:displayname>
Example collection
Goland et al. [Page 23]
INTERNET-DRAFT WebDAV April 7, 1998
</D:displayname>
<D:resourcetype><D:collection/></D:resourcetype>
<D:supportedlock>
<D:lockentry>
<D:exclusive/><D:write/>
</D:lockentry>
<D:lockentry>
<D:shared/><D:write/>
</D:lockentry>
</D:supportedlock>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>http://www.foo.bar/container/front.html</D:href>
<D:propstat>
<D:prop>
<R:bigbox>
<R:BoxType>Box type B</R:BoxType>
</R:bigbox>
<D:creationdate>
1997-12-01T18:27:21-08:00
</D:creationdate>
<D:displayname>
Example HTML resource
</D:displayname>
<D:getcontentlength>
4525
</D:getcontentlength>
<D:getcontenttype>
text/html
</D:getcontenttype>
<D:getetag>
zzyzx
</D:getetag>
<D:getlastmodified>
Monday, 12-Jan-98 09:25:56 GMT
</D:getlastmodified>
<D:resourcetype/>
<D:supportedlock>
<D:lockentry>
<D:exclusive/><D:write/>
</D:lockentry>
<D:lockentry>
<D:shared/><D:write/>
</D:lockentry>
</D:supportedlock>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
Goland et al. [Page 24]
INTERNET-DRAFT WebDAV April 7, 1998 lock. In this example, PROPFIND was invoked on both these examples, as specified in
section 7.6, an If header must be submitted containing a lock token
for both the resource
http://www.foo.bar/container/ with source and destination.
7.8 Refreshing Write Locks
A client MUST NOT submit the same write lock request twice. Note
that a Depth header of 1, meaning client is always aware it is resubmitting the same lock
request applies to because it must include the resource and its children, and a propfind XML
element containing lock token in the allprop XML element, meaning If header in
order to make the request
should return the name and value of all properties defined on each
resource.
The for a resource http://www.foo.bar/container/ has six properties
defined on it:
http://www.foo.bar/boxschema/bigbox,
http://www.foo.bar/boxschema/author, DAV:creationdate,
DAV:displayname, DAV:resourcetype, and DAV:supportedlock.
The last four properties are WebDAV-specific, defined in section 12.
Since GET is not supported on this resource, the get* properties
(e.g., getcontentlength) are not defined on this resource. The DAV-
specific properties assert that "container" was created on December
1, 1997, at 5:42:21PM, in is already locked.
However, a time zone 8 hours west of GMT
(creationdate), has client may submit a name of "Example collection" (displayname), LOCK method with an If header but
without a
collection resource type (resourcetype), and supports exclusive
write and shared write locks (supportedlock).
The resource http://www.foo.bar/container/front.html has nine
properties defined on it:
http://www.foo.bar/boxschema/bigbox (another instance body. This form of LOCK MUST only be used to "refresh" a
lock. Meaning, at minimum, that any timers associated with the
"bigbox" property type), DAV:creationdate, DAV:displayname,
DAV:getcontentlength, DAV:getcontenttype, DAV:getetag,
DAV:getlastmodified, DAV:resourcetype, and DAV:supportedlock.
The DAV-specific properties assert lock
MUST be re-set.
A server may return a Timeout header with a lock refresh that "front.html" is
different than the Timeout header returned when the lock was created on
December 1, 1997, at 6:27:21PM,
originally requested. Additionally clients may submit Timeout
headers of arbitrary value with their lock refresh requests.
Servers, as always, may ignore Timeout headers submitted by the
client.
If an error is received in response to a time zone refresh LOCK request the
client SHOULD assume that the lock was not refreshed.
8 hours west of GMT
(creationdate), has a name of "Example HTML resource" (displayname),
a content length of 4525 bytes (getcontentlength), HTTP Methods for Distributed Authoring
The following new HTTP methods use XML as a MIME type of
"text/html" (getcontenttype), an entity tag of "zzyzx" (getetag),
was last modified on Monday, January 12, 1998, at 09:25:56 GMT
(getlastmodified), has an empty resource type, meaning that it is
not a collection (resourcetype), request and supports both exclusive write response
format. All DAV compliant clients and shared write locks (supportedlock).
7.1.3 Example - Using propname to Retrieve all Property Names
>>Request
PROPFIND /container/ HTTP/1.1
Host: www.foo.bar
Content-Type: text/xml
Content-Length: xxxxx
Goland et al. [Page 25]
INTERNET-DRAFT WebDAV April 7, 1998
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:propfind>
<D:propname/>
</D:propfind>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml
Content-Length: xxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.foo.bar/boxschema/" prefix="R" ?>
<D:multistatus>
<D:response>
<D:href>http://www.foo.bar/container/</D:href>
<D:propstat>
<D:prop>
<R:bigbox/>
<R:author/>
<D:creationdate/>
<D:displayname/>
<D:resourcetype/>
<D:supportedlock/>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>http://www.foo.bar/container/front.html</D:href>
<D:propstat>
<D:prop>
<R:bigbox/>
<D:creationdate/>
<D:displayname/>
<D:getcontentlength/>
<D:getcontenttype/>
<D:getetag/>
<D:getlastmodified/>
<D:resourcetype/>
<D:supportedlock/>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
In this example, PROPFIND is invoked on resources MUST use XML
parsers that are compliant with [REC-XML]. All XML used in either
requests or responses MUST be, at minimum, well formed. If a server
receives ill-formed XML in a request it MUST reject the collection resource
http://www.foo.bar/container/, entire
request with a propfind 400 (Bad Request). If a client receives ill-formed
XML element in a response then it MUST NOT assume anything about the outcome
of the executed method and SHOULD treat the server as
malfunctioning.
Goland et al. [Page 26] 23]
INTERNET-DRAFT WebDAV April 7, October 22, 1998
containing the propname XML element, meaning the name of all
8.1 PROPFIND
The PROPFIND method retrieves properties should be returned. Since no depth header is present, it
assumes its default value of "infinity", meaning defined on the name of Request-URI,
if the
properties resource does not have any internal members, or on the collection
Request-URI and all potentially its progeny should be returned.
Consistent with the previous example, resource
http://www.foo.bar/container/ has six properties defined on it,
http://www.foo.bar/boxschema/bigbox,
http://www.foo.bar/boxschema/author, DAV:creationdate,
DAV:displayname, DAV:resourcetype, and DAV:supportedlock.
The resource http://www.foo.bar/container/index.html, a member of
the "container" collection, has nine properties defined on it,
http://www.foo.bar/boxschema/bigbox, DAV:creationdate,
DAV:displayname, DAV:getcontentlength, DAV:getcontenttype,
DAV:getetag, DAV:getlastmodified, DAV:resourcetype, and
DAV:supportedlock.
7.2 PROPPATCH
The PROPPATCH method processes instructions specified in the request
body to set and/or remove properties defined on resources, if the resource
identified by the Request-URI.
does have internal members. All DAV compliant resources MUST
support the PROPPATCH PROPFIND method and
MUST process instructions that are specified using the
propertyupdate, set, and remove propfind XML element (section
12.14) along with all XML elements defined for use with that
element.
A client may submit a Depth header with a value of the DAV schema.
Execution of the directives in this method is, of course, subject to
access control constraints. "0", "1", or
"infinity" with a PROPFIND on a resource with internal members. DAV
compliant resources SHOULD servers MUST support the setting of arbitrary dead properties.
The request message body of a PROPPATCH "0", "1" and "infinity"
behaviors. By default, the PROPFIND method without a Depth header
MUST contain the
propertyupdate act as if a "Depth: infinity" header was included.
A client may submit a propfind XML element. Instruction processing MUST occur element in the order instructions are received (i.e., from top body of the
request method describing what information is being requested. It
is possible to bottom).
Instructions MUST either request particular property values, all be executed property
values, or none executed. Thus if
any error occurs during processing all executed instructions MUST be
undone and a proper error result returned. Instruction processing
details can be found in list of the definition names of the set and remove
instructions in section 11.13.
7.2.1 Status Codes for use with Multi-Status
The following are examples of response codes one would expect to be
used in a Multi-Status response for this method. Note, however,
that unless explicitly prohibited any 2/3/4/5xx series response code resource's properties. A
client may be used in choose not to submit a Multi-Status response.
200 OK - The command succeeded. As there can request body. An empty PROPFIND
request body MUST be treated as a mixture of sets request for the names and removes in values
of all properties.
All servers MUST support returning a body, response of content type
text/xml or application/xml that contains a 201 Created seems inappropriate.
403 Forbidden - The client, for reasons multistatus XML element
that describes the server chooses not to
specify, cannot alter one results of the attempts to retrieve the various
properties.
Goland et al. [Page 27]
INTERNET-DRAFT WebDAV April 7, 1998
409 Conflict - The client has provided
If there is an error retrieving a value whose semantics are
not appropriate for property then a proper error
result MUST be included in the property. This includes trying response. A request to set read-
only properties.
423 Locked - The specified resource retrieve the
value of a property which does not exist is locked an error and MUST be
noted, if the client either
is not response uses a lock owner or multistatus XML element, with a
response XML element which contains a 404 (Not Found) status value.
Consequently, the lock type requires multistatus XML element for a lock token to be
submitted and resource with
members MUST include a response XML element for each member of the client did not submit it.
425 Insufficient Space
resource, to whatever depth was requested. Each response XML element
MUST contain an href XML element that identifies the resource on Resource - The server did
which the properties in the prop XML element are defined. Results
for a PROPFIND on a resource with internal members are returned as a
flat list whose order of entries is not significant.
In the case of allprop and propname, if a principal does not have
sufficient space
the right to record know whether a particular property exists then the property.
7.2.2
property should be silently excluded from the response.
The results of this method SHOULD NOT be cached.
Goland et al. [Page 24]
INTERNET-DRAFT WebDAV October 22, 1998
8.1.1 Example - PROPPATCH Retrieving Named Properties
>>Request
PROPPATCH /bar.html
PROPFIND /file HTTP/1.1
Host: www.foo.com
Content-Type: text/xml www.foo.bar
Content-type: text/xml; charset="utf-8"
Content-Length: xxxx xyz
<?xml version="1.0" encoding="utf-8" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.w3.com/standards/z39.50/" prefix="Z"
?>
<D:propertyupdate>
<D:set>
<D:prop>
<Z:authors>
<Z:Author>Jim Whitehead</Z:Author>
<Z:Author>Roy Fielding</Z:Author>
</Z:authors>
<D:propfind xmlns:D="DAV:">
<D:prop xmlns:R="http://www.foo.bar/boxschema/">
<R:bigbox/>
<R:author/>
<R:DingALing/>
<R:Random/>
</D:prop>
</D:set>
<D:remove>
<D:prop><Z:Copyright-Owner/></D:prop>
</D:remove>
</D:propertyupdate>
Goland et al. [Page 28]
INTERNET-DRAFT WebDAV April 7, 1998
</D:propfind>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.w3.com/standards/z39.50/" prefix="Z"
?>
<D:multistatus>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>http://www.foo.com/bar.html</D:href>
<D:href>http://www.foo.bar/file</D:href>
<D:propstat>
<D:prop><Z:Authors/></D:prop>
<D:prop xmlns:R="http://www.foo.bar/boxschema/">
<R:bigbox>
<R:BoxType>Box type A</R:BoxType>
</R:bigbox>
<R:author>
<R:Name>J.J. Johnson</R:Name>
</R:author>
</D:prop>
<D:status>HTTP/1.1 424 Method Failure</D:status> 200 OK</D:status>
</D:propstat>
<D:propstat>
<D:prop><Z:Copyright-Owner/></D:prop>
<D:prop><R:DingALing/><R:Random/></D:prop>
<D:status>HTTP/1.1 409 Conflict</D:status>
</D:propstat> 403 Forbidden</D:status>
<D:responsedescription> Copyright Owner can The user does not be deleted or
altered.</D:responsedescription> have access to
the DingALing property.
</D:responsedescription>
</D:propstat>
</D:response>
<D:responsedescription> There has been an access violation error.
</D:responsedescription>
</D:multistatus>
Goland et al. [Page 25]
INTERNET-DRAFT WebDAV October 22, 1998
In this example, PROPFIND is executed on a non-collection resource
http://www.foo.bar/file. The propfind XML element specifies the client requests the server to set the value
name of four properties whose values are being requested. In this
case only two properties were returned, since the http://www.w3.com/standards/z39.50/Authors property, and to
remove the property http://www.w3.com/standards/z39.50/Copyright-
Owner. Since principal issuing
the Copyright-Owner property could request did not be removed, no
property modifications occur. The Method Failure status code for
the Authors property indicates this action would have succeeded if
it were not for the conflict with removing the Copyright-Owner
property.
7.3 MKCOL Method
The MKCOL method is used sufficient access rights to create a new collection. All DAV
compliant resources MUST support the MKCOL method.
7.3.1 Request
MKCOL creates a new collection resource at the location specified by
the Request-URI. If the resource identified by the Request-URI is
non-null then the MKCOL MUST fail. During MKCOL processing, a
server MUST make the Request-URI a member of its parent collection,
unless the Request-URI is "/". If no such ancestor exists, the
method MUST fail. When the MKCOL operation creates a new collection
resource, all ancestors MUST already exist, or see the method MUST fail
with a 409 Conflict status code. For example, if a request third
and fourth properties.
8.1.2 Example - Using allprop to
create Retrieve All Properties
>>Request
PROPFIND /container/ HTTP/1.1
Host: www.foo.bar
Depth: 1
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:">
<D:allprop/>
</D:propfind>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>http://www.foo.bar/container/</D:href>
<D:propstat>
<D:prop xmlns:R="http://www.foo.bar/boxschema/">
<R:bigbox>
<R:BoxType>Box type A</R:BoxType>
</R:bigbox>
<R:author>
<R:Name>Hadrian</R:Name>
</R:author>
<D:creationdate>
1997-12-01T17:42:21-08:00
</D:creationdate>
<D:displayname>
Example collection /a/b/c/d/ is made, and neither /a/b/ nor /a/b/c/
exists, the request must fail.
</D:displayname>
<D:resourcetype><D:collection/></D:resourcetype>
<D:supportedlock>
<D:lockentry>
<D:lockscope><D:exclusive/></D:lockscope>
<D:locktype><D:write/></D:locktype>
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When MKCOL is invoked without a request body, the newly created
collection SHOULD have no members.
A MKCOL request message may contain a message body. The behavior of
</D:lockentry>
<D:lockentry>
<D:lockscope><D:shared/></D:lockscope>
<D:locktype><D:write/></D:locktype>
</D:lockentry>
</D:supportedlock>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>http://www.foo.bar/container/front.html</D:href>
<D:propstat>
<D:prop xmlns:R="http://www.foo.bar/boxschema/">
<R:bigbox>
<R:BoxType>Box type B</R:BoxType>
</R:bigbox>
<D:creationdate>
1997-12-01T18:27:21-08:00
</D:creationdate>
<D:displayname>
Example HTML resource
</D:displayname>
<D:getcontentlength>
4525
</D:getcontentlength>
<D:getcontenttype>
text/html
</D:getcontenttype>
<D:getetag>
zzyzx
</D:getetag>
<D:getlastmodified>
Monday, 12-Jan-98 09:25:56 GMT
</D:getlastmodified>
<D:resourcetype/>
<D:supportedlock>
<D:lockentry>
<D:lockscope><D:exclusive/></D:lockscope>
<D:locktype><D:write/></D:locktype>
</D:lockentry>
<D:lockentry>
<D:lockscope><D:shared/></D:lockscope>
<D:locktype><D:write/></D:locktype>
</D:lockentry>
</D:supportedlock>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
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In this example, PROPFIND was invoked on the resource
http://www.foo.bar/container/ with a MKCOL request when Depth header of 1, meaning the body is present is limited
request applies to creating
collections, members of the resource and its children, and a collection, bodies propfind XML
element containing the allprop XML element, meaning the request
should return the name and value of members all properties defined on each
resource.
The resource http://www.foo.bar/container/ has six properties
defined on it:
http://www.foo.bar/boxschema/bigbox,
http://www.foo.bar/boxschema/author, DAV:creationdate,
DAV:displayname, DAV:resourcetype, and DAV:supportedlock.
The last four properties are WebDAV-specific, defined in section 13.
Since GET is not supported on this resource, the collections or members. If the server receives a
MKCOL request entity type it does get* properties
(e.g., getcontentlength) are not support or understand it MUST
respond with a 415 Unsupported Media Type status code. The exact
behavior of MKCOL for various request media types is undefined in defined on this document, and will be specified in separate documents.
7.3.2 Response Codes
Responses from a MKCOL request MUST NOT be cached as MKCOL has non-
idempotent semantics.
201 Created - resource. The collection or structured resource DAV-
specific properties assert that "container" was created on December
1, 1997, at 5:42:21PM, in
its entirety.
403 Forbidden - This indicates at least one a time zone 8 hours west of two conditions: 1)
the server does not allow the creation GMT
(creationdate), has a name of collections at the given
location in its namespace, or 2) the parent "Example collection" (displayname), a
collection resource type (resourcetype), and supports exclusive
write and shared write locks (supportedlock).
The resource http://www.foo.bar/container/front.html has nine
properties defined on it:
http://www.foo.bar/boxschema/bigbox (another instance of the
Request-URI exists but cannot accept members.
405 Method Not Allowed - MKCOL can only be executed
"bigbox" property type), DAV:creationdate, DAV:displayname,
DAV:getcontentlength, DAV:getcontenttype, DAV:getetag,
DAV:getlastmodified, DAV:resourcetype, and DAV:supportedlock.
The DAV-specific properties assert that "front.html" was created on a
deleted/non-existent resource.
409 Conflict - A collection cannot be made
December 1, 1997, at the Request-URI until
one or more intermediate collections have been created.
415 Unsupported Media Type- The server does not support the request 6:27:21PM, in a time zone 8 hours west of GMT
(creationdate), has a name of "Example HTML resource" (displayname),
a content length of 4525 bytes (getcontentlength), a MIME type of the body.
425 Insufficient Space
"text/html" (getcontenttype), an entity tag of "zzyzx" (getetag),
was last modified on Resource - The Monday, January 12, 1998, at 09:25:56 GMT
(getlastmodified), has an empty resource does type, meaning that it is
not have
sufficient space to record the state of the resource after the
execution of this method.
7.3.3 Example - MKCOL
This example creates a collection called /webdisc/xfiles/ on the
server www.server.org.
>>Request
MKCOL /webdisc/xfiles/ HTTP/1.1
Host: www.server.org
>>Response
HTTP/1.1 201 Created (resourcetype), and supports both exclusive write
and shared write locks (supportedlock).
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7.4 GET, HEAD for Collections
The semantics of GET are unchanged when applied
8.1.3 Example - Using propname to a collection,
since GET is defined as, "retrieve whatever information (in the form
of an entity) Retrieve all Property Names
>>Request
PROPFIND /container/ HTTP/1.1
Host: www.foo.bar
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<propfind xmlns="DAV:">
<propname/>
</propfind>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?>
<multistatus xmlns="DAV:">
<response>
<href>http://www.foo.bar/container/</href>
<propstat>
<prop xmlns:R="http://www.foo.bar/boxschema/">
<R:bigbox/>
<R:author/>
<creationdate/>
<displayname/>
<resourcetype/>
<supportedlock/>
</prop>
<status>HTTP/1.1 200 OK</status>
</propstat>
</response>
<response>
<href>http://www.foo.bar/container/front.html</href>
<propstat>
<prop xmlns:R="http://www.foo.bar/boxschema/">
<R:bigbox/>
<creationdate/>
<displayname/>
<getcontentlength/>
<getcontenttype/>
<getetag/>
<getlastmodified/>
<resourcetype/>
<supportedlock/>
</prop>
<status>HTTP/1.1 200 OK</status>
</propstat>
</response>
</multistatus>
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In this example, PROPFIND is identified by invoked on the Request-URI" [Fielding et al.,
1997]. GET when applied to a collection may return the contents of
an "index.html" resource, resource
http://www.foo.bar/container/, with a human-readable view of propfind XML element
containing the contents of propname XML element, meaning the collection, or something else altogether. Hence it name of all
properties should be returned. Since no Depth header is possible
that present, it
assumes its default value of "infinity", meaning the result name of a GET the
properties on a the collection will bear no correlation to and all its progeny should be returned.
Consistent with the membership previous example, resource
http://www.foo.bar/container/ has six properties defined on it,
http://www.foo.bar/boxschema/bigbox,
http://www.foo.bar/boxschema/author, DAV:creationdate,
DAV:displayname, DAV:resourcetype, and DAV:supportedlock.
The resource http://www.foo.bar/container/index.html, a member of
the collection.
Similarly, since "container" collection, has nine properties defined on it,
http://www.foo.bar/boxschema/bigbox, DAV:creationdate,
DAV:displayname, DAV:getcontentlength, DAV:getcontenttype,
DAV:getetag, DAV:getlastmodified, DAV:resourcetype, and
DAV:supportedlock.
This example also demonstrates the definition use of HEAD is a GET without a response
message body, XML namespace scoping, and
the semantics of HEAD are unmodified when applied to
collection resources.
7.5 POST for Collections default namespace. Since by definition the actual function performed by POST is
determined by "xmlns" attibute does not contain
an explicit "shorthand name" (prefix) letter, the server and often depends on the particular
resource, the behavior of POST when applied to collections cannot be
meaningfully modified because it is largely undefined. Thus the
semantics of POST are unmodified when applied namespace applies
by default to a collection.
7.6 DELETE
7.6.1 DELETE for Non-Collection Resources
If all enclosed elements. Hence, all elements which do
not explicitly state the DELETE method is issued namespace to a non-collection resource which is
an internal member they belong are members
of a collection, then during DELETE processing a
server MUST remove the Request-URI from its parent collection.
7.6.2 DELETE for Collections "DAV:" namespace schema.
8.2 PROPPATCH
The DELETE PROPPATCH method processes instructions specified in the request
body to set and/or remove properties defined on a collection the resource
identified by the Request-URI.
All DAV compliant resources MUST act as if a "Depth: infinity"
header was used on it. A client support the PROPPATCH method and
MUST NOT submit a Depth header with
a DELETE on a collection with any value but infinity.
DELETE instructs process instructions that the collection are specified in using the request-URI
propertyupdate, set, and all its internal member resources are to be deleted.
If any member cannot be deleted then all remove XML elements of the member's ancestors
MUST NOT be deleted, so as to maintain DAV schema.
Execution of the namespace.
Any headers included with DELETE MUST be applied directives in processing every
resource this method is, of course, subject to be deleted.
When
access control constraints. DAV compliant resources SHOULD support
the DELETE setting of arbitrary dead properties.
The request message body of a PROPPATCH method has completed MUST contain the
propertyupdate XML element. Instruction processing it MUST return a
consistent namespace. occur in
the order instructions are received (i.e., from top to bottom).
Instructions MUST either all be executed or none executed. Thus if
any error occurs during processing all executed instructions MUST be
undone and a proper error result returned. Instruction processing
details can be found in the definition of the set and remove
instructions in section 12.13.
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If an error occurs
8.2.1 Status Codes for use with a resource other than the resource
identified in the request URI then the 207 (Multi-Status)
The following are examples of response MUST codes one would expect to be
used in a 207 Multi-
Status. 424 Method Failure errors SHOULD NOT (Multi-Status) response for this method. Note,
however, that unless explicitly prohibited any 2/3/4/5xx series
response code may be used in the a 207 Multi-
Status. They (Multi-Status) response.
200 (OK) - The command succeeded. As there can be safely left out because the client will know
that the ancestors a mixture of sets
and removes in a resource could body, a 201 (Created) seems inappropriate.
403 (Forbidden) - The client, for reasons the server chooses not be deleted when to
specify, cannot alter one of the properties.
409 (Conflict) - The client receives an error has provided a value whose semantics are
not appropriate for the ancestor's progeny. Additionally
204 No Content errors SHOULD NOT be returned in the 207 Multi-
Status. property. This includes trying to set read-
only properties.
423 (Locked) - The reason for this prohibition specified resource is that 204 No Content locked and the client
either is not a lock owner or the default success code.
7.6.2.1 Example lock type requires a lock token to
be submitted and the client did not submit it.
507 (Insufficient Storage) - DELETE
>>Request
DELETE /container/ HTTP/1.1
Host: www.foo.bar The server did not have sufficient
space to record the property.
8.2.2 Example - PROPPATCH
>>Request
PROPPATCH /bar.html HTTP/1.1
Host: www.foo.com
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:propertyupdate xmlns:D="DAV:"
xmlns:Z="http://www.w3.com/standards/z39.50/">
<D:set>
<D:prop>
<Z:authors>
<Z:Author>Jim Whitehead</Z:Author>
<Z:Author>Roy Fielding</Z:Author>
</Z:authors>
</D:prop>
</D:set>
<D:remove>
<D:prop><Z:Copyright-Owner/></D:prop>
</D:remove>
</D:propertyupdate>
>>Response
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HTTP/1.1 207 Multi-Status
Content-Type: text/xml text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<?xml:namespace ns="DAV:" prefix="d" ?>
<d:multistatus>
<d:response>
<d:href>http://www.foo.bar/container/resource3</d:href>
<d:status>HTTP/1.1 423 Locked</d:status>
</d:response>
</d:multistatus>
<D:multistatus xmlns:D="DAV:"
xmlns:Z="http://www.w3.com/standards/z39.50">
<D:response>
<D:href>http://www.foo.com/bar.html</D:href>
<D:propstat>
<D:prop><Z:Authors/></D:prop>
<D:status>HTTP/1.1 424 Failed Dependency</D:status>
</D:propstat>
<D:propstat>
<D:prop><Z:Copyright-Owner/></D:prop>
<D:status>HTTP/1.1 409 Conflict</D:status>
</D:propstat>
<D:responsedescription> Copyright Owner can not be deleted or
altered.</D:responsedescription>
</D:response>
</D:multistatus>
In this example the attempt to delete
http://www.foo.bar/container/resource3 failed because it is locked,
and no lock token was submitted with example, the request. Consequently, client requests the
attempt server to delete http://www.foo.bar/container/ also failed. Thus set the client knows that value of
the attempt http://www.w3.com/standards/z39.50/Authors property, and to delete
http://www.foo.bar/container/ must have also failed since
remove the parent
can property http://www.w3.com/standards/z39.50/Copyright-
Owner. Since the Copyright-Owner property could not be deleted unless its child has also been deleted. Even
though a Depth header has removed, no
property modifications occur. The 424 (Failed Dependency) status
code for the Authors property indicates this action would have
succeeded if it were not been included, a depth of infinity is
assumed because for the conflict with removing the
Copyright-Owner property.
8.3 MKCOL Method
The MKCOL method is on used to create a new collection.
7.7 PUT
7.7.1 PUT for Non-Collection Resources
A PUT performed on an existing All DAV
compliant resources MUST support the MKCOL method.
8.3.1 Request
MKCOL creates a new collection resource replaces at the GET response
entity of location specified by
the resource. Properties defined on Request-URI. If the resource may be
recomputed during PUT processing but are not otherwise affected.
For example, if a server recognizes the content type of identified by the request
body, it may be able to automatically extract information that could
be profitably exposed as properties.
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A PUT that would result in Request-URI is
non-null then the creation of a resource without an
appropriately scoped parent collection MKCOL MUST fail with fail. During MKCOL processing, a 409
Conflict.
7.7.2 PUT for Collections
As defined in the HTTP/1.1 specification [Fielding et al., 1997],
the "PUT method requests that the enclosed entity be stored under
server MUST make the supplied Request-URI." Since submission of an entity
representing Request-URI a collection would implicitly encode creation and
deletion member of resources, this specification intentionally does not
define a transmission format for creating a collection using PUT.
Instead, its parent collection,
unless the MKCOL method Request-URI is defined to create collections. "/". If no such ancestor exists, the
method MUST fail. When the PUT MKCOL operation creates a new non-collection resource collection
resource, all ancestors MUST already exist. If all ancestors do not exist, or the method MUST fail
with a 409 Conflict (Conflict) status code. For example, if
resource /a/b/c/d.html is a request to be created
create collection /a/b/c/d/ is made, and neither /a/b/ nor /a/b/c/ does not exist,
then
exists, the request must fail.
7.8 COPY Method
The COPY method creates
When MKCOL is invoked without a duplicate of the source resource, given by
the Request-URI, in the destination resource, given by request body, the
Destination header. The Destination header MUST be present. newly created
collection SHOULD have no members.
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A MKCOL request message may contain a message body. The
exact behavior of
a MKCOL request when the COPY method depends on the type of the source
resource.
All WebDAV compliant resources MUST support the COPY method.
However, support for the COPY method does not guarantee the ability body is present is limited to copy creating
collections, members of a resource. For example, separate programs may control
resources collection, bodies of members and
properties on the same server. As collections or members. If the server receives a result,
MKCOL request entity type it may does not be possible
to copy a resource to support or understand it MUST
respond with a location that appears to be on the same
server.
7.8.1 COPY 415 (Unsupported Media Type) status code. The exact
behavior of MKCOL for HTTP/1.1 resources
When the source resource various request media types is not undefined in
this document, and will be specified in separate documents.
8.3.2 Status Codes
Responses from a MKCOL request MUST NOT be cached as MKCOL has non-
idempotent semantics.
201 (Created) - The collection the result or structured resource was created in
its entirety.
403 (Forbidden) - This indicates at least one of two conditions: 1)
the COPY
method is server does not allow the creation of collections at the given
location in its namespace, or 2) the parent collection of the
Request-URI exists but cannot accept members.
405 (Method Not Allowed) - MKCOL can only be executed on a new resource
deleted/non-existent resource.
409 (Conflict) - A collection cannot be made at the destination whose
state and behavior match that Request-URI
until one or more intermediate collections have been created.
415 (Unsupported Media Type)- The server does not support the
request type of the source body.
507 (Insufficient Storage) - The resource as closely as
possible. However, does not have sufficient
space to record the exact state and behavior of the destination resource depend on what information after the source resource is able to
provide and what information the destination resource is able to
accept.
Subsequent alterations to the destination resource will not modify
the source resource. Subsequent alterations to the source resource
will not modify execution of
this method.
8.3.3 Example - MKCOL
This example creates a collection called /webdisc/xfiles/ on the destination resource.
server www.server.org.
>>Request
MKCOL /webdisc/xfiles/ HTTP/1.1
Host: www.server.org
>>Response
HTTP/1.1 201 Created
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All properties on the source resource MUST be duplicated on the
destination resource, subject to modifying headers and XML elements,
following the definition for copying properties.
7.8.2 COPY
8.4 GET, HEAD for Properties Collections
The following section defines how properties on a resource semantics of GET are
handled during unchanged when applied to a COPY operation.
Live properties SHOULD be duplicated as identically behaving live
properties at collection,
since GET is defined as, "retrieve whatever information (in the destination resource. If a property cannot be
copied live, then its value MUST be duplicated, octet-for-octet, in form
of an identically named, dead property on entity) is identified by the destination resource
subject Request-URI" [RFC2068]. GET when
applied to a collection may return the effects contents of an "index.html"
resource, a human-readable view of the propertybehavior XML element.
The propertybehavior XML element can specify that properties are
copied on best effort, that all live properties must be successfully
copied or contents of the method must fail, collection,
or something else altogether. Hence it is possible that a specified list of live
properties must be successfully copied or the method must fail. The
propertybehavior XML element is defined in section 11.12.
7.8.3 COPY for Collections
The COPY method result
of a GET on a collection will bear no correlation to the membership
of the collection.
Similarly, since the definition of HEAD is a GET without a response
message body, the semantics of HEAD are unmodified when applied to
collection resources.
8.5 POST for Collections
Since by definition the actual function performed by POST is
determined by the server and often depends on the particular
resource, the behavior of POST when applied to collections cannot be
meaningfully modified because it is largely undefined. Thus the
semantics of POST are unmodified when applied to a collection.
8.6 DELETE
8.6.1 DELETE for Non-Collection Resources
If the DELETE method is issued to a non-collection resource which is
an internal member of a collection, then during DELETE processing a
server MUST remove the Request-URI from its parent collection.
8.6.2 DELETE for Collections
The DELETE method on a collection without a Depth header MUST act as if a Depth "Depth: infinity"
header with value "infinity" was included. used on it. A client may MUST NOT submit a Depth header on with
a COPY DELETE on a collection with a any value of "0"
or "infinity". DAV compliant servers MUST support the "0" and
"infinity" Depth header behaviors.
A COPY of depth infinity but infinity.
DELETE instructs that the collection specified in the Request-URI is to be copied to the location specified in the
Destination header,
and all its internal member resources are to be
copied to a location relative to it, recursively through deleted.
If any member cannot be deleted then all levels
of the collection hierarchy.
A COPY of depth "0" only instructs that the collection and its
properties but not its internal members, are to member's ancestors
MUST NOT be copied. deleted, so as to maintain the namespace.
Any headers included with a COPY DELETE MUST be applied in processing every
resource to be copied with the exception of deleted.
When the Destination header.
The Destination header only specifies the destination for the
Request-URI. When applied to members of the collection specified in
the request-URI the value of Destination is to be modified to
reflect the current location in the hierarchy. So, if the request-
URI is /a/ and the destination is /b/ then when /a/c/d is processed
it must use a destination of /b/c/d.
When the COPY DELETE method has completed processing it MUST have created return a
consistent namespace at the destination. However, if an error
occurs while copying an internal member collection, the server MUST
NOT copy any members of this collection. After detecting an error,
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the COPY operation SHOULD try to finish as much of the original copy
operation as possible. So, for example, if an infinite depth copy
operation is performed on collection /a/, which contains collections
/a/b/ and /a/c/, and an error occurs copying /a/b/, an attempt
should still be made to copy /a/c/. Similarly, after encountering an
error copying a non-collection resource as part of an infinite depth
copy, the server SHOULD try to finish as much of the original copy
operation as possible. namespace.
If an error in executing the COPY method occurs with a resource other than the resource
identified in the request URI Request-URI then the response MUST be a 207 Multi-Status.
(Multi-Status). 424 Method Failure (Failed Dependency) errors SHOULD NOT be returned in the
207 Multi-
Status from a COPY method. These responses (Multi-Status). They can be safely omitted left out because the client
will know that the progeny ancestors of a resource could not be copied deleted when
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the client receives an error for the parent. ancestor's progeny.
Additionally 201 Created/204 No Content response codes 204 (No Content) errors SHOULD NOT be returned as values in the
207 Multi-Status responses from COPY methods.
They, too, can be safely omitted because they are (Multi-Status). The reason for this prohibition is that 204 (No
Content) is the default success codes.
7.8.4 COPY and the Overwrite Header
If a resource exists at code.
8.6.2.1 Example - DELETE
>>Request
DELETE /container/ HTTP/1.1
Host: www.foo.bar
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<d:multistatus xmlns:d="DAV:">
<d:response>
<d:href>http://www.foo.bar/container/resource3</d:href>
<d:status>HTTP/1.1 423 Locked</d:status>
</d:response>
</d:multistatus>
In this example the destination attempt to delete
http://www.foo.bar/container/resource3 failed because it is locked,
and no lock token was submitted with the Overwrite header is
"T" then prior request. Consequently, the
attempt to performing delete http://www.foo.bar/container/ also failed. Thus
the copy client knows that the server MUST perform attempt to delete
http://www.foo.bar/container/ must have also failed since the parent
can not be deleted unless its child has also been deleted. Even
though a
DELETE with Depth Infinity on the destination resource. If the
Overwrite header has not been included, a depth of infinity is set to "F" then
assumed because the operation will fail.
7.8.5 Status Codes
201 Created - The source method is on a collection.
8.7 PUT
8.7.1 PUT for Non-Collection Resources
A PUT performed on an existing resource was successfully copied. The copy
operation resulted in replaces the creation GET response
entity of a new the resource.
204 No Content - The source Properties defined on the resource was successfully copied to may be
recomputed during PUT processing but are not otherwise affected.
For example, if a
pre-existing destination resource.
412 Precondition Failed - The server was unable to maintain recognizes the
liveness content type of the properties listed request
body, it may be able to automatically extract information that could
be profitably exposed as properties.
A PUT that would result in the propertybehavior XML
element or the Overwrite header is "F" and the state creation of the
destination a resource is non-null.
423 Locked - The destination resource was locked.
425 Insufficient Space on Resource - The destination resource does
not have sufficient space to record without an
appropriately scoped parent collection MUST fail with a 409
(Conflict).
Goland et al. [Page 35]
INTERNET-DRAFT WebDAV October 22, 1998
8.7.2 PUT for Collections
As defined in the state of HTTP/1.1 specification [RFC2068], the resource after "PUT method
requests that the execution enclosed entity be stored under the supplied
Request-URI." Since submission of an entity representing a
collection would implicitly encode creation and deletion of
resources, this method.
502 Bad Gateway - This may occur when specification intentionally does not define a
transmission format for creating a collection using PUT. Instead,
the destination MKCOL method is on another
server and the destination server refuses defined to accept create collections.
When the resource.
Goland et al. [Page 35]
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7.8.6 Example - COPY with Overwrite
This example shows PUT operation creates a new non-collection resource
http://www.ics.uci.edu/~fielding/index.html being copied to all
ancestors MUST already exist. If all ancestors do not exist, the
location http://www.ics.uci.edu/users/f/fielding/index.html. The
204 No Content
method MUST fail with a 409 (Conflict) status code indicates the existing code. For example, if
resource at /a/b/c/d.html is to be created and /a/b/c/ does not exist,
then the
destination was overwritten.
>>Request
COPY /~fielding/index.html HTTP/1.1
Host: www.ics.uci.edu
Destination: http://www.ics.uci.edu/users/f/fielding/index.html
>>Response
HTTP/1.1 204 No Content
7.8.7 Example - request must fail.
8.8 COPY with No Overwrite Method
The following example shows COPY method creates a duplicate of the same copy operation being performed,
but with source resource, given by
the Overwrite header set to "F." A response of 412
Precondition Failed is returned because Request-URI, in the destination resource has
a non-null state.
>>Request
COPY /~fielding/index.html HTTP/1.1
Host: www.ics.uci.edu
Destination: http://www.ics.uci.edu/users/f/fielding/index.html
Overwrite: F
>>Response
HTTP/1.1 412 Precondition Failed
7.8.8 Example - COPY of a Collection
>>Request
COPY /container/ HTTP/1.1
Host: www.foo.bar
Destination: http://www.foo.bar/othercontainer/
Depth: infinity
Content-Type: text/xml
Content-Length: xxxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="d" ?>
<d:propertybehavior>
<d:keepalive>*</d:keepalive>
</d:propertybehavior>
Goland et al. [Page 36]
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>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml
Content-Length: xxxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="d" ?>
<d:multistatus>
<d:response>
<d:href>http://www.foo.bar/othercontainer/R2/</d:href>
<d:status>HTTP/1.1 412 Precondition Failed</d:status>
</d:response>
</d:multistatus>
The Depth header is unnecessary as the default behavior of COPY on a
collection is to act as if a "Depth: infinity" header had been
submitted. In this example most of the resources, along with the
collection, were copied successfully. However the collection R2
failed, most likely due to a problem with maintaining the liveness
of properties (this is specified by the propertybehavior XML
element). Because there was an error copying R2, none of R2's
members were copied. However no errors were listed for those
members due to the error minimization rules resource, given in section 7.8.3.
7.9 MOVE Method
The MOVE operation on a non-collection resource is the logical
equivalent of a copy (COPY) followed by a delete of the source,
where the actions are performed atomically. Consequently, the
Destination header. The Destination header MUST be present on all MOVE methods and MUST
follow all COPY requirements for present. The
exact behavior of the COPY part method depends on the type of the MOVE method. source
resource.
All DAV WebDAV compliant resources MUST support the MOVE COPY method.
However, support for the MOVE COPY method does not guarantee the ability
to move a
resource to copy a particular destination. resource. For example, separate programs may actually control different sets
of
resources on the same server. Therefore, As a result, it may not be possible
to move copy a resource within to a namespace location that appears to belong to be on the same
server.
If
8.8.1 COPY for HTTP/1.1 resources
When the source resource is not a collection the result of the COPY
method is the creation of a new resource exists at the destination, the destination whose
state and behavior match that of the source resource
will be DELETEd as closely as
possible. After a side-effect of successful COPY invocation, all properties on the MOVE operation,
source resource MUST be duplicated on the destination resource,
subject to modifying headers and XML elements, following the
definition for copying properties. Since the environment at the
destination may be different than at the source due to factors
outside the restrictions scope of control of the Overwrite header.
7.9.1 MOVE server, such as the absence of
resources required for Properties
The correct operation, it may not be possible to
completely duplicate the behavior of properties on a MOVE, including the effects of resource at the
propertybehavior XML element, MUST be
destination. Subsequent alterations to the same as specified in destination resource will
not modify the source resource. Subsequent alterations to the
source resource will not modify the destination resource.
8.8.2 COPY for Properties
The following section 7.8.2. defines how properties on a resource are
handled during a COPY operation.
Goland et al. [Page 37] 36]
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7.9.2 MOVE for Collections
A MOVE of depth infinity instructs that the collection specified in
the Request-URI
Live properties SHOULD be moved to the location specified in duplicated as identically behaving live
properties at the
Destination header, and all destination resource. If a property cannot be
copied live, then its internal member resources are to value MUST be
moved to locations relative duplicated, octet-for-octet, in
an identically named, dead property on the destination resource
subject to it, recursively through all levels the effects of the collection hierarchy.
The MOVE propertybehavior XML element.
The propertybehavior XML element can specify that properties are
copied on best effort, that all live properties must be successfully
copied or the method must fail, or that a specified list of live
properties must be successfully copied or the method must fail. The
propertybehavior XML element is defined in section 12.12.
8.8.3 COPY for Collections
The COPY method on a collection without a Depth header MUST act as
if a Depth "infinity" header with value "infinity" was used on it. included. A client MUST NOT may
submit a Depth header on a
MOVE COPY on a collection with any a value but of "0"
or "infinity". DAV compliant servers MUST support the "0" and
"infinity" Depth header behaviors.
A COPY of depth infinity instructs that the collection specified in
the Request-URI is to be copied to the location specified in the
Destination header, and all its internal member resources are to be
copied to a location relative to it, recursively through all levels
of the collection hierarchy.
A COPY of "Depth: 0" only instructs that the collection and its
properties but not its internal members, are to be copied.
Any headers included with MOVE a COPY MUST be applied in processing every
resource to be moved copied with the exception of the Destination header.
The behavior Destination header only specifies the destination for the
Request-URI. When applied to members of the collection specified in
the Request-URI the value of Destination header is to be modified to
reflect the same as given for COPY
on collections. current location in the hierarchy. So, if the Request-
URI is /a/ and the destination is /b/ then when /a/c/d is processed
it must use a destination of /b/c/d.
When the MOVE COPY method has completed processing it MUST have created a
consistent namespace on both at the source and destination. destination (see section 5.1 for the
definition of namespace consistency). However, if an error occurs
while moving copying an internal member collection, the server MUST NOT move
copy any members of the failed collection.. In this
case, after detecting collection (i.e., the server must skip this
subtree), as this would create an inconsistent namespace. After
detecting an error, the move COPY operation SHOULD try to finish as much
of the original move copy operation as possible. possible (i.e., the server should
still attempt to copy other subtrees and their members, that are not
descendents of an error-causing collection). So, for example, if an
infinite depth move copy operation is performed on collection /a/, which
contains collections /a/b/ and /a/c/, and an error occurs moving copying
Goland et al. [Page 37]
INTERNET-DRAFT WebDAV October 22, 1998
/a/b/, an attempt should still be made to try moving copy /a/c/. Similarly,
after encountering an error moving copying a non-collection resource as
part of an infinite depth move, copy, the server SHOULD try to finish as
much of the original move copy operation as possible.
If an error in executing the COPY method occurs with a resource
other than the resource identified in the request URI Request-URI then the
response MUST be a 207 Multi-
Status. (Multi-Status).
The 424 Method Failure errors (Failed Dependency) status code SHOULD NOT be returned as values in
the 207 Multi-Status (Multi-Status) response from a MOVE COPY method. These errors responses
can be safely omitted because the client will know that the progeny
of a resource could not be moved copied when the client receives an error
for the parent. Additionally 201 Created/204 No Content responses (Created)/204 (No Content) status
codes SHOULD NOT be returned as values in 207 Multi-Status (Multi-Status)
responses from MOVES. These
responses COPY methods. They, too, can be safely omitted
because they are the default success codes.
7.9.3 MOVE
8.8.4 COPY and the Overwrite Header
If a resource exists at the destination and the Overwrite header is
"T" then prior to performing the move copy the server MUST perform a
DELETE with Depth infinity "Depth: infinity" on the destination resource. If the
Overwrite header is set to "F" then the operation will fail.
Goland et al. [Page 38]
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7.9.4
8.8.5 Status Codes
201 Created (Created) - The source resource was successfully moved, and copied. The
copy operation resulted in the creation of a new
resource was created at the destination. resource.
204 No Content (No Content) - The source resource was successfully moved copied to a
pre-existing destination resource.
403 (Forbidden) _ The source and destination URIs are the same.
409 (Conflict) _ A resource cannot be created at the destination
until one or more intermediate collections have been created.
412 Precondition Failed (Precondition Failed) - The server was unable to maintain the
liveness of the properties listed in the propertybehavior XML
element or the Overwrite header is "F" and the state of the
destination resource is non-null.
423 Locked (Locked) - The source or the destination resource was locked.
507 (Insufficient Storage) - The destination resource does not have
sufficient space to record the state of the resource after the
execution of this method.
502 Bad Gateway (Bad Gateway) - This may occur when the destination is on
another server and the destination server refuses to accept the
resource.
7.9.5
Goland et al. [Page 38]
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8.8.6 Example - MOVE of a Non-Collection COPY with Overwrite
This example shows resource
http://www.ics.uci.edu/~fielding/index.html being moved copied to the
location http://www.ics.uci.edu/users/f/fielding/index.html. The
contents of the destination resource would have been overwritten if
204 (No Content) status code indicates the destination existing resource had been non-null. In this case, since
there was nothing at the
destination resource, the response code is
201 Created. was overwritten.
>>Request
MOVE
COPY /~fielding/index.html HTTP/1.1
Host: www.ics.uci.edu
Destination: http://www.ics.uci.edu/users/f/fielding/index.html
>>Response
HTTP/1.1 201 Created
Content-Location: http://www.ics.uci.edu/users/f/fielding/index.html
7.9.6 204 No Content
8.8.7 Example - MOVE of a Collection
>>Request
MOVE COPY with No Overwrite
The following example shows the same copy operation being performed,
but with the Overwrite header set to "F." A response of 412
(Precondition Failed) is returned because the destination resource
has a non-null state.
>>Request
COPY /~fielding/index.html HTTP/1.1
Host: www.ics.uci.edu
Destination: http://www.ics.uci.edu/users/f/fielding/index.html
Overwrite: F
>>Response
HTTP/1.1 412 Precondition Failed
8.8.8 Example - COPY of a Collection
>>Request
COPY /container/ HTTP/1.1
Host: www.foo.bar
Destination: http://www.foo.bar/othercontainer/
Overwrite: F
If: (<opaquelocktoken:fe184f2e-6eec-41d0-c765-01adc56e6bb4>)
(<opaquelocktoken:e454f3f3-acdc-452a-56c7-00a5c91e4b77>)
Depth: infinity
Content-Type: text/xml text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<d:propertybehavior xmlns:d="DAV:">
<d:keepalive>*</d:keepalive>
</d:propertybehavior>
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Content-Length: xyz
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="d" ?>
<d:propertybehavior>
<d:keepalive>*</d:keepalive>
</d:propertybehavior>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml text/xml; charset="utf-8"
Content-Length: zzz xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<?xml:namespace ns="DAV:" prefix="d" ?>
<d:multistatus>
<d:multistatus xmlns:d="DAV:">
<d:response>
<d:href>http://www.foo.bar/othercontainer/C2/</d:href>
<d:href>http://www.foo.bar/othercontainer/R2/</d:href>
<d:status>HTTP/1.1 423 Locked</d:status> 412 Precondition Failed</d:status>
</d:response>
</d:multistatus>
The Depth header is unnecessary as the default behavior of COPY on a
collection is to act as if a "Depth: infinity" header had been
submitted. In this example the client has submitted a number most of lock tokens the resources, along with the request. A lock token will need
collection, were copied successfully. However the collection R2
failed, most likely due to be submitted for every
resource, both source and destination, anywhere in a problem with maintaining the scope liveness
of the
method, that properties (this is locked. In this case the proper lock token was not
submitted for the destination http://www.foo.bar/othercontainer/C2/.
This means that specified by the resource /container/C2/ could not be moved. propertybehavior XML
element). Because there was an error copying /container/C2/, R2, none of
/container/C2's R2's
members were copied. However no errors were listed for those
members due to the error minimization rules given in section 7.8.3. User agent authentication has previously occurred
via a mechanism outside the scope of the HTTP protocol, in an
underlying transport layer.
7.10 LOCK 8.8.3.
8.9 MOVE Method
The following sections describe the LOCK method, which MOVE operation on a non-collection resource is used to
take out the logical
equivalent of a lock copy (COPY) followed by a delete of any access type. These sections on the LOCK
method describe only those semantics that source,
where the actions are specific to performed atomically. Consequently, the LOCK
method
Destination header MUST be present on all MOVE methods and are independent MUST
follow all COPY requirements for the COPY part of the access type MOVE method.
All DAV compliant resources MUST support the MOVE method. However,
support for the MOVE method does not guarantee the ability to move a
resource to a particular destination.
For example, separate programs may actually control different sets
of resources on the lock being
requested.
Any same server. Therefore, it may not be possible
to move a resource which supports within a namespace that appears to belong to the LOCK method MUST,
same server.
If a resource exists at minimum,
support the XML request and response formats defined herein.
7.10.1 Operation
A LOCK method invocation creates destination, the lock specified by destination resource
will be DELETEd as a side-effect of the lockinfo
XML element on MOVE operation, subject to
the Request-URI. Lock method requests SHOULD have restrictions of the Overwrite header.
8.9.1 MOVE for Properties
The behavior of properties on a MOVE, including the effects of the
propertybehavior XML request body which contains an owner XML element for this lock element, MUST be the same as specified in
section 8.8.2.
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INTERNET-DRAFT WebDAV April 7, October 22, 1998
request, unless this is a refresh request. The LOCK request may have
a Timeout header.
Clients MUST assume
8.9.2 MOVE for Collections
A MOVE with "Depth: infinity" instructs that locks may arbitrarily disappear at any
time, regardless of the value given collection
specified in the Timeout header. The
Timeout header only indicates the behavior of Request-URI be moved to the server if
"extraordinary" circumstances do not occur. For example, an
administrator may remove a lock at any time or the system may crash location specified in such a way that it loses
the record Destination header, and all its internal member resources are to
be moved to locations relative to it, recursively through all levels
of the lock's existence. collection hierarchy.
The
response MOVE method on a collection MUST contain the value of the lockdiscovery property in act as if a
prop XML element.
7.10.2 The Effect of Locks "Depth: infinity"
header was used on Properties and Collections
The scope of a lock is the entire state of the resource, including
its body and associated properties. As it. A client MUST NOT submit a result, Depth header on a lock
MOVE on a
resource collection with any value but "infinity".
Any headers included with MOVE MUST also lock be applied in processing every
resource to be moved with the resource's properties.
For collections, a lock also affects exception of the ability to add or remove
members. Destination header.
The nature behavior of the effect depends upon Destination header is the type of access
control involved.
7.10.3 Locking Replicated Resources
Some servers automatically replicate resources across multiple URLs.
In such a circumstance same as given for COPY
on collections.
When the server MOVE method has completed processing it MUST only accept have created a lock
consistent namespace on one of both the URLs source and destination (see section
5.1 for the definition of namespace consistency). However, if an
error occurs while moving an internal member collection, the server can guarantee that
MUST NOT move any members of the lock will be honored
across all failed collection (i.e., the URLs.
7.10.4 Depth and Locking
The Depth header may be used with the LOCK method. Values other
than 0 or infinity MUST NOT be used with server
must skip the Depth header on a LOCK
method. All resources that support error-causing subtree), as this would create an
inconsistent namespace. In this case, after detecting the LOCK method MUST support error, the
Depth header.
A Depth header of value 0 means
move operation SHOULD try to just lock the resource specified
by finish as much of the request-URI.
If original move as
possible (i.e., the Depth header is set server should still attempt to infinity then the resource specified
in the request-URI along with all its internal move other
subtrees and their members, all the way
down the hierarchy, that are to not descendents of an error-
causing collection). So, for example, if an infinite depth move is
performed on collection /a/, which contains collections /a/b/ and
/a/c/, and an error occurs moving /a/b/, an attempt should still be locked. A successful result MUST
return
made to try moving /a/c/. Similarly, after encountering an error
moving a single lock token which represents all non-collection resource as part of an infinite depth move,
the resources that
have been locked. server SHOULD try to finish as much of the original move
operation as possible.
If an UNLOCK is successfully executed on this
token, all associated resources are unlocked. If error occurs with a resource other than the lock cannot resource
identified in the Request-URI then the response MUST be
granted to all resources, a 409 Conflict 207
(Multi-Status).
The 424 (Failed Dependency) status code MUST SHOULD NOT be returned with a response entity body containing a multistatus XML
element describing which resource(s) prevented in
the lock 207 (Multi-Status) response from being
granted. Hence, partial success is a MOVE method. These errors
can be safely omitted because the client will know that the progeny
of a resource could not be moved when the client receives an option. Either error
for the
entire hierarchy is locked or no resources parent. Additionally 201 (Created)/204 (No Content)
responses SHOULD NOT be returned as values in 207 (Multi-Status)
responses from a MOVE. These responses can be safely omitted
because they are locked. the default success codes.
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INTERNET-DRAFT WebDAV April 7, October 22, 1998
8.9.3 MOVE and the Overwrite Header
If no depth a resource exists at the destination and the Overwrite header is submitted on a LOCK request
"T" then prior to performing the request
MUST act as if a Depth of infinity had been submitted.
7.10.5 Interaction with other Methods
The interaction of a LOCK with various methods is dependent upon move the
lock type. However, independent of lock type, a successful DELETE
of a resource server MUST cause all of its locks to be removed.
7.10.6 Lock Compatibility Table
The table below describes the behavior that occurs when perform a lock
request is made
DELETE with "Depth: infinity" on a the destination resource.
Current lock state/ Shared Lock Exclusive
Lock request Lock
None True True
Shared Lock True False
Exclusive Lock False False*
Legend: True = lock may be granted. False = lock MUST NOT be
granted. *=It If the
Overwrite header is illegal for a principal set to request "F" then the same lock
twice. operation will fail.
8.9.4 Status Codes
201 (Created) - The current lock state of a source resource is given in the leftmost
column, was successfully moved, and lock requests are listed in the first row. The
intersection of a row and column gives
new resource was created at the result of a lock request.
For example, if a shared lock is held on destination.
204 (No Content) - The source resource was successfully moved to a resource,
pre-existing destination resource.
403 (Forbidden) _ The source and an
exclusive lock is requested, the table entry is "false", indicating destination URIs are the lock must not same.
409 (Conflict) _ A resource cannot be granted.
7.10.7 Status Codes
200 Success created at the destination
until one or more intermediate collections have been created.
412 (Precondition Failed) - The lock request succeeded and server was unable to maintain the value
liveness of the
lockdiscovery property is included properties listed in the body.
412 Precondition Failed propertybehavior XML
element or the Overwrite header is "F" and the state of the
destination resource is non-null.
423 (Locked) - The included lock token was not
enforceable on this resource source or the destination resource was locked.
502 (Bad Gateway) - This may occur when the destination is on
another server could not satisfy and the
request in destination server refuses to accept the lockinfo XML element.
423 Locked
resource.
8.9.5 Example - MOVE of a Non-Collection
This example shows resource
http://www.ics.uci.edu/~fielding/index.html being moved to the
location http://www.ics.uci.edu/users/f/fielding/index.html. The
contents of the destination resource is locked, so would have been overwritten if
the method has destination resource had been
rejected. non-null. In this case, since
there was nothing at the destination resource, the response code is
201 (Created).
>>Request
MOVE /~fielding/index.html HTTP/1.1
Host: www.ics.uci.edu
Destination: http://www.ics.uci.edu/users/f/fielding/index.html
>>Response
HTTP/1.1 201 Created
Location: http://www.ics.uci.edu/users/f/fielding/index.html
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7.10.8
8.9.6 Example - Simple Lock Request MOVE of a Collection
>>Request
LOCK /workspace/webdav/proposal.doc
MOVE /container/ HTTP/1.1
Host: webdav.sb.aol.com
Timeout: Infinite, Second-4100000000 www.foo.bar
Destination: http://www.foo.bar/othercontainer/
Overwrite: F
If: (<opaquelocktoken:fe184f2e-6eec-41d0-c765-01adc56e6bb4>)
(<opaquelocktoken:e454f3f3-acdc-452a-56c7-00a5c91e4b77>)
Content-Type: text/xml text/xml; charset="utf-8"
Content-Length: xyz
Authorization: Digest username="ejw",
realm="ejw@webdav.sb.aol.com", nonce="...",
uri="/workspace/webdav/proposal.doc",
response="...", opaque="..."
<?xml version="1.0" encoding="utf-8" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:lockinfo>
<D:lockscope><D:exclusive/></D:lockscope>
<D:locktype><D:write/></D:locktype>
<D:owner>
<D:href>http://www.ics.uci.edu/~ejw/contact.html</D:href>
</D:owner>
</D:lockinfo>
<d:propertybehavior xmlns:d='DAV:'>
<d:keepalive>*</d:keepalive>
</d:propertybehavior>
>>Response
HTTP/1.1 200 OK 207 Multi-Status
Content-Type: text/xml text/xml; charset="utf-8"
Content-Length: xxxxx zzz
<?xml version="1.0" encoding="utf-8" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:prop>
<D:lockdiscovery>
<D:activelock>
<D:locktype><D:write/></D:locktype>
<D:lockscope><D:exclusive/></D:lockscope>
<D:depth>Infinity</D:depth>
<D:owner>
<D:href>
http://www.ics.uci.edu/~ejw/contact.html
</D:href>
</D:owner>
<D:timeout>Second-604800</D:timeout>
<D:locktoken>
<D:href>
opaquelocktoken:e71d4fae-5dec-22d6-fea5-00a0c91e6be4
</D:href>
</D:locktoken>
</D:activelock>
</D:lockdiscovery>
</D:prop>
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This
<d:multistatus xmlns:d='DAV:'>
<d:response>
<d:href>http://www.foo.bar/othercontainer/C2/</d:href>
<d:status>HTTP/1.1 423 Locked</d:status>
</d:response>
</d:multistatus>
In this example shows the successful creation client has submitted a number of an exclusive write lock on resource
http://webdav.sb.aol.com/workspace/webdav/proposal.doc. The
resource http://www.ics.uci.edu/~ejw/contact.html contains contact
information for the owner of the lock. The server has an activity-
based timeout policy in place on this resource, which causes tokens
with the request. A lock token will need to automatically be removed after 1 week (604800 seconds).
Note that the nonce, response, submitted for every
resource, both source and opaque fields have not been
calculated destination, anywhere in the Authorization request header.
7.10.9 Example - Refreshing a Write Lock
>>Request
LOCK /workspace/webdav/proposal.doc HTTP/1.1
Host: webdav.sb.aol.com
Timeout: Infinite, Second-4100000000
If: (<opaquelocktoken:e71d4fae-5dec-22d6-fea5-00a0c91e6be4>)
Authorization: Digest username="ejw",
realm="ejw@webdav.sb.aol.com", nonce="...",
uri="/workspace/webdav/proposal.doc",
response="...", opaque="..."
>>Response
HTTP/1.1 200 OK
Content-Type: text/xml
Content-Length: xxxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:prop>
<D:lockdiscovery>
<D:activelock>
<D:locktype><D:write/></D:locktype>
<D:lockscope><D:exclusive/></D:lockscope>
<D:depth>Infinity</D:depth>
<D:owner>
<D:href>
http://www.ics.uci.edu/~ejw/contact.html
</D:href>
</D:owner>
<D:timeout>Second-604800</D:timeout>
<D:locktoken>
<D:href>
opaquelocktoken:e71d4fae-5dec-22d6-fea5-00a0c91e6be4
</D:href>
</D:locktoken>
</D:activelock>
</D:lockdiscovery>
</D:prop>
Goland et al. [Page 44]
INTERNET-DRAFT WebDAV April 7, 1998
This request would refresh scope of the lock, resetting any time outs.
Notice
method, that the client asked for an infinite time out but the server
choose to ignore the request. is locked. In this example, case the nonce, response,
and opaque fields have proper lock token was not been calculated in
submitted for the Authorization
request header.
7.10.10 Example - Multi-Resource Lock Request
>>Request
LOCK /webdav/ HTTP/1.1
Host: webdav.sb.aol.com
Timeout: Infinite, Second-4100000000
Depth: infinity
Authorization: Digest username="ejw",
realm="ejw@webdav.sb.aol.com", nonce="...",
uri="/workspace/webdav/proposal.doc",
response="...", opaque="..."
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:lockinfo>
<D:locktype><D:write/></D:locktype>
<D:lockscope><D:exclusive/></D:lockscope>
<D:owner>
<D:href>http://www.ics.uci.edu/~ejw/contact.html</D:href>
</D:owner>
</D:lockinfo>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml
Content-Length: xxxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:multistatus>
<D:response>
<D:href>http://webdav.sb.aol.com/webdav/secret</D:href>
<D:status>HTTP/1.1 403 Forbidden</D:status>
</D:response>
<D:response>
<D:href>http://webdav.sb.aol.com/webdav/</D:href>
<D:propstat>
<D:prop><D:lockdiscovery/></D:prop>
<D:status>HTTP/1.1 424 Method Failure</D:status>
</D:propstat>
</D:response>
</D:multistatus>
Goland et al. [Page 45]
INTERNET-DRAFT WebDAV April 7, 1998 destination http://www.foo.bar/othercontainer/C2/.
This example shows a request for an exclusive write lock on a
collection and all its children. In this request, the client has
specified means that it desires an infinite length lock, if available,
otherwise a timeout of 4.1 billion seconds, if available. The
request entity body contains the contact information for the
principal taking out the lock, in this case a web page URL.
The error is a 403 Forbidden response on the resource
http://webdav.sb.aol.com/webdav/secret. Because this resource /container/C2/ could not be locked, moved.
Because there was an error copying /container/C2/, none of the resources
/container/C2's members were locked. Note also that
the lockdiscovery property copied. However no errors were listed
for those members due to the Request-URI error minimization rules given in
section 8.8.3. User agent authentication has been included as
required. In this example the lockdiscovery property is empty which
means that there are no outstanding locks on previously occurred
via a mechanism outside the resource.
In this example, scope of the nonce, response, and opaque fields have not
been calculated HTTP protocol, in the Authorization request header.
7.11 UNLOCK an
underlying transport layer.
8.10 LOCK Method
The UNLOCK method removes following sections describe the LOCK method, which is used to
take out a lock identified by of any access type. These sections on the lock token in
the Lock-Token request header from LOCK
method describe only those semantics that are specific to the Request-URI, LOCK
method and all other
resources included in are independent of the lock. If all resources which have been
locked under access type of the submitted lock token can not be unlocked then the
UNLOCK request MUST fail. being
requested.
Goland et al. [Page 43]
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Any DAV compliant resource which supports the LOCK method MUST MUST, at minimum,
support the UNLOCK method.
7.11.1 Example - UNLOCK
>>Request
UNLOCK /workspace/webdav/info.doc HTTP/1.1
Host: webdav.sb.aol.com
Lock-Token: <opaquelocktoken:a515cfa4-5da4-22e1-f5b5-00a0451e6bf7>
Authorization: Digest username="ejw",
realm="ejw@webdav.sb.aol.com", nonce="...",
uri="/workspace/webdav/proposal.doc",
response="...", opaque="..."
>>Response
HTTP/1.1 204 No Content
In this example, XML request and response formats defined herein.
8.10.1 Operation
A LOCK method invocation creates the lock identified specified by the lock token
"opaquelocktoken:a515cfa4-5da4-22e1-f5b5-00a0451e6bf7" is
successfully removed from lockinfo
XML element on the resource
http://webdav.sb.aol.com/workspace/webdav/info.doc. If Request-URI. Lock method requests SHOULD have a
XML request body which contains an owner XML element for this lock
included more than just one resource, the lock
request, unless this is removed from all
resources included in the lock. a refresh request. The 204 status code is used instead LOCK request may have
a Timeout header.
Clients MUST assume that locks may arbitrarily disappear at any
time, regardless of 200 OK because there is no response entity body.
Goland et al. [Page 46]
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In this example, the nonce, response, and opaque fields have not
been calculated value given in the Authorization request Timeout header.
8 HTTP Headers for Distributed Authoring
8.1 DAV Header
DAV = "DAV" ":" "1" ["," "2"] ["," 1#extend]
This The
Timeout header only indicates that the resource supports behavior of the DAV schema and
protocol as specified. All DAV compliant resources MUST return server if
"extraordinary" circumstances do not occur. For example, an
administrator may remove a lock at any time or the
DAV header on all OPTIONS responses. system may crash
in such a way that it loses the record of the lock's existence. The
response MUST contain the value is a list of all compliance classes that the resource
supports. Note that above lockdiscovery property in a comma has already been added
prop XML element.
In order to indicate the 2.
This is because lock token associated with a resource can not newly created
lock, a Lock-Token response header MUST be level 2 compliant unless it is
also level 1 compliant. Please refer to section 14 included in the response
for more details.
In general, however, support every successful LOCK request for one compliance class does a new lock. Note that the
Lock-Token header would not
entail support be returned in the response for any other.
8.2 Depth Header
Depth = "Depth" ":" ("0" | "1" | "infinity") a
successful refresh LOCK request because a new lock was not created.
8.10.2 The Depth header is used with methods executed Effect of Locks on resources which
could potentially have internal members to indicate whether the
method Properties and Collections
The scope of a lock is to be applied only to the resource (Depth = 0), to entire state of the
resource and resource, including
its immediate children, (Depth = 1), or the resource body and all its progeny (Depth = infinity).
The Depth header is only supported if associated properties. As a method's definition
explicitly provides for such support.
The following rules are the default behavior for any method that
supports result, a lock on a
resource MUST also lock the Depth header. A method may override these defaults by
defining different behavior in its definition.
Methods which support resource's properties.
For collections, a lock also affects the Depth header may choose not ability to support all add or remove
members. The nature of the header's values and effect depends upon the type of access
control involved.
8.10.3 Locking Replicated Resources
A resource may define, be made available through more than one URI. However
locks apply to resources, not URIs. Therefore a LOCK request on a case
resource MUST NOT succeed if can not be honored by case basis, all the
behavior of URIs
through which the method if a Depth header resource is not present. For
example, the MOVE method only supports addressable.
8.10.4 Depth = infinity and if a Locking
The Depth header is not present will act as if a Depth = may be used with the LOCK method. Values other
than 0 or infinity header
had been applied.
Clients MUST NOT rely upon methods executing on members of their
hierarchies in any particular order or on the execution being atomic
unless the particular method explicitly provides such guarantees.
Upon execution, a method be used with a the Depth header will perform as much of
its assigned task as possible and then return on a response specifying
what it was able to accomplish and what it failed to do. LOCK
method. All resources that support the LOCK method MUST support the
Depth header.
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So, for example, an attempt to COPY a hierarchy may result in some
A Depth header of value 0 means to just lock the members being copied and some not.
Any headers on a method that has a defined interaction with resource specified
by the Request-URI.
If the Depth header MUST be applied is set to all resources in the scope of infinity then the
method except where alternative behavior is explicitly defined. For
example, an If-Match header will have its value applied against
every resource specified
in the method's scope and will cause the method to
fail if the header fails to match.
If a resource, source or destination, within the scope of the method Request-URI along with a depth header is locked in such a all its internal members, all the way as to prevent
down the hierarchy, are to be locked. A successful execution of the method, then the result MUST
return a single lock token for that
resource MUST be submitted with the request in which represents all the resources that
have been locked. If an UNLOCK is successfully executed on this
token, all associated resources are unlocked. If request
header.
The Depth header only specifies the behavior of the method with
regards lock cannot be
granted to internal children. If all resources, a resource does not have internal
children then the Depth header 409 (Conflict) status code MUST be ignored.
Please note, however, that it
returned with a response entity body containing a multistatus XML
element describing which resource(s) prevented the lock from being
granted. Hence, partial success is always not an error to submit a value
for option. Either the
entire hierarchy is locked or no resources are locked.
If no Depth header that is not allowed by the method's definition.
Thus submitting a "Depth: 1" submitted on a COPY, even if LOCK request then the resource does
not have internal members, will result in request
MUST act as if a 400 Bad Request. "Depth:infinity" had been submitted.
8.10.5 Interaction with other Methods
The
method should fail not because interaction of a LOCK with various methods is dependent upon the
lock type. However, independent of lock type, a successful DELETE
of a resource doesn't have internal
members, but because MUST cause all of the illegal value in the header.
8.3 Destination Header
Destination = "Destination" ":" URI its locks to be removed.
8.10.6 Lock Compatibility Table
The Destination header specifies table below describes the behavior that occurs when a destination resource for methods
such as COPY and MOVE, which take two URIs as parameters.
8.4 If Header
If = "If" ":" ( 1*No-tag-list lock
request is made on a resource.
Current lock state/ | 1*Tagged-list)
No-tag-list = List
Tagged-list = Resource 1*List
Resource = Coded-url
List = "(" 1*(["Not"](State-token Shared Lock | "[" entity-tag "]")) ")"
State-token Exclusive
Lock request | | Lock
=====================+=================+===============
None | True | True
---------------------+-----------------+---------------
Shared Lock | True | False
---------------------+-----------------+---------------
Exclusive Lock | False | False*
-------------------------------------------------------
Legend: True = Coded-url
Coded-url lock may be granted. False = "<" URI ">"
The If header is intended to have similar functionality to the If-
Match header defined in section 14.25 of [Fielding et al., 1997].
However the If header lock MUST NOT be
granted. *=It is intended illegal for use with any URI which
represents state information, referred to as a principal to request the same lock
twice.
The current lock state token, about a
resource as well as e-tags. A typical example of a state token resource is a
lock token, given in the leftmost
column, and lock tokens requests are the only state tokens defined listed in
this specification.
Goland et al. [Page 48]
INTERNET-DRAFT WebDAV April 7, 1998
All DAV compliant resources MUST honor the If header. first row. The If header's purpose is to describe a series of state lists. If
the state of the resource to which the header is applied does not
match any of the specified state lists then the request MUST fail
with a 412 Precondition Failed. If one of the described state lists
matches the state
intersection of the resource then the request may succeed.
8.4.1 No-tag-list Production
The No-tag-list production describes a series of state tokens row and e-
tags. If multiple No-tag-list productions are used then only one
needs to match column gives the state result of the resource for the method to be
allowed to continue.
If a method, due to the presence of lock request.
For example, if a Depth or Destination header, shared lock is applied to multiple resources then the No-tag-list production
MUST be applied to each resource held on a resource, and an
exclusive lock is requested, the method table entry is applied to.
8.4.1.1 Example "false", indicating
the lock must not be granted.
Goland et al. [Page 45]
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8.10.7 Status Codes
200 (OK) - No-tag-list If Header
If: (<locktoken:a-write-lock-token> ["I am an e-tag"]) (["I am
another e-tag"]) The previous header would require that any resources within lock request succeeded and the
scope value of the method must either be locked with
lockdiscovery property is included in the specified body.
412 (Precondition Failed) - The included lock token and in was not
enforceable on this resource or the state identified by server could not satisfy the "I am an e-tag" e-tag or
request in the state identified by the second e-tag "I am another e-tag". To
put the matter more plainly one can think of the previous If header
as being in the form (or (and <locktoken:a-write-lock-token> ["I am
an e-tag"]) (and ["I am another e-tag"])).
8.4.2 Tagged-list Production
The tagged-list production scopes a list production. That is, it
specifies that the lists following the resource specification only
apply to the specified resource. lockinfo XML element.
423 (Locked) - The scope of the resource
production begins with is locked, so the list production immediately following method has been
rejected.
8.10.8 Example - Simple Lock Request
>>Request
LOCK /workspace/webdav/proposal.doc HTTP/1.1
Host: webdav.sb.aol.com
Timeout: Infinite, Second-4100000000
Content-Type: text/xml; charset="utf-8"
Content-Length: xyz
Authorization: Digest username="ejw",
realm="ejw@webdav.sb.aol.com", nonce="...",
uri="/workspace/webdav/proposal.doc",
response="...", opaque="..."
<?xml version="1.0" encoding="utf-8" ?>
<D:lockinfo xmlns:D='DAV:'>
<D:lockscope><D:exclusive/></D:lockscope>
<D:locktype><D:write/></D:locktype>
<D:owner>
<D:href>http://www.ics.uci.edu/~ejw/contact.html</D:href>
</D:owner>
</D:lockinfo>
Goland et al. [Page 46]
INTERNET-DRAFT WebDAV October 22, 1998
>>Response
HTTP/1.1 200 OK
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:prop xmlns:D="DAV:">
<D:lockdiscovery>
<D:activelock>
<D:locktype><D:write/></D:locktype>
<D:lockscope><D:exclusive/></D:lockscope>
<D:depth>Infinity</D:depth>
<D:owner>
<D:href>
http://www.ics.uci.edu/~ejw/contact.html
</D:href>
</D:owner>
<D:timeout>Second-604800</D:timeout>
<D:locktoken>
<D:href>
opaquelocktoken:e71d4fae-5dec-22d6-fea5-00a0c91e6be4
</D:href>
</D:locktoken>
</D:activelock>
</D:lockdiscovery>
</D:prop>
This example shows the successful creation of an exclusive write
lock on resource production and ends with the next
http://webdav.sb.aol.com/workspace/webdav/proposal.doc. The
resource production, if
any.
When the If header is applied to a particular resource, the Tagged-
list productions MUST be searched to determine if any of the listed
resources match the operand resource(s) http://www.ics.uci.edu/~ejw/contact.html contains contact
information for the current method. If
none owner of the resource productions match the current resource then lock. The server has an activity-
based timeout policy in place on this resource, which causes the
header MUST
lock to automatically be ignored. If one of the resource productions does
match removed after 1 week (604800 seconds).
Note that the name of the resource under consideration then the list
productions following the resource production MUST be applied to the
resource in the manner specified nonce, response, and opaque fields have not been
calculated in the previous section. Authorization request header.
Goland et al. [Page 49] 47]
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The same URI MUST NOT appear more than once in a resource production
in an If header.
8.4.2.1
8.10.9 Example - Tagged List If header
COPY /resource1 Refreshing a Write Lock
>>Request
LOCK /workspace/webdav/proposal.doc HTTP/1.1
Host: www.foo.bar
Destination: http://www.foo.bar/resource2 webdav.sb.aol.com
Timeout: Infinite, Second-4100000000
If: <http://www.foo.bar/resource1> (<locktoken:a-write-lock-token>
[W/"A weak e-tag"]) (["strong e-tag"])
<http://www.bar.bar/random>(["another strong e-tag"])
In this example http://www.foo.bar/resource1 is being copied to
http://www.foo.bar/resource2. When the method is first applied to
http://www.foo.bar/resource1, resource1 must be in (<opaquelocktoken:e71d4fae-5dec-22d6-fea5-00a0c91e6be4>)
Authorization: Digest username="ejw",
realm="ejw@webdav.sb.aol.com", nonce="...",
uri="/workspace/webdav/proposal.doc",
response="...", opaque="..."
>>Response
HTTP/1.1 200 OK
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:prop xmlns:D="DAV:">
<D:lockdiscovery>
<D:activelock>
<D:locktype><D:write/></D:locktype>
<D:lockscope><D:exclusive/></D:lockscope>
<D:depth>Infinity</D:depth>
<D:owner>
<D:href>
http://www.ics.uci.edu/~ejw/contact.html
</D:href>
</D:owner>
<D:timeout>Second-604800</D:timeout>
<D:locktoken>
<D:href>
opaquelocktoken:e71d4fae-5dec-22d6-fea5-00a0c91e6be4
</D:href>
</D:locktoken>
</D:activelock>
</D:lockdiscovery>
</D:prop>
This request would refresh the state
specified by "(<locktoken:a-write-lock-token> [W/"A weak e-tag"])
(["strong e-tag"])", lock, resetting any time outs.
Notice that is, it either must be locked with a lock
token of "locktoken:a-write-lock-token" and have a weak entity tag
W/"A weak e-tag" or it must have a strong entity tag "strong e-tag".
That is the only success condition since the resource
http://www.bar.bar/random never has client asked for an infinite time out but the method applied server
choose to it (the
only other resource listed in ignore the If header) request. In this example, the nonce, response,
and
http://www.foo.bar/resource2 is opaque fields have not listed been calculated in the If Authorization
request header.
8.4.3 not Production
Every state token or e-tag is either current, and hence describes
the state of a resource, or is not current,
Goland et al. [Page 48]
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8.10.10 Example - Multi-Resource Lock Request
>>Request
LOCK /webdav/ HTTP/1.1
Host: webdav.sb.aol.com
Timeout: Infinite, Second-4100000000
Depth: infinity
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxxx
Authorization: Digest username="ejw",
realm="ejw@webdav.sb.aol.com", nonce="...",
uri="/workspace/webdav/proposal.doc",
response="...", opaque="..."
<?xml version="1.0" encoding="utf-8" ?>
<D:lockinfo xmlns:D="DAV:">
<D:locktype><D:write/></D:locktype>
<D:lockscope><D:exclusive/></D:lockscope>
<D:owner>
<D:href>http://www.ics.uci.edu/~ejw/contact.html</D:href>
</D:owner>
</D:lockinfo>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>http://webdav.sb.aol.com/webdav/secret</D:href>
<D:status>HTTP/1.1 403 Forbidden</D:status>
</D:response>
<D:response>
<D:href>http://webdav.sb.aol.com/webdav/</D:href>
<D:propstat>
<D:prop><D:lockdiscovery/></D:prop>
<D:status>HTTP/1.1 424 Failed Dependency</D:status>
</D:propstat>
</D:response>
</D:multistatus>
This example shows a request for an exclusive write lock on a
collection and does not describe all its children. In this request, the state of client has
specified that it desires an infinite length lock, if available,
otherwise a resource. The boolean operation timeout of matching a state
token or e-tag to 4.1 billion seconds, if available. The
request entity body contains the current state of a resource thus resolves to contact information for the
principal taking out the lock, in this case a
true or false value. The not production is used to reverse that
value. web page URL.
Goland et al. [Page 49]
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The scope of the not production error is the state-token or
entity-tag immediately following it.
If: (Not <locktoken:write1> <locktoken:write2>)
When submitted with a request, 403 (Forbidden) response on the resource
http://webdav.sb.aol.com/webdav/secret. Because this If header requires that all
operand resources must resource could
not be locked with locktoken:write1 and must
be locked with locktoken:write2.
8.4.4 Matching Function
When performing If header processing, the definition locked, none of a matching
state token or entity tag is as follows.
Matching entity tag: Where the entity tag matches an entity tag
associated with resources were locked. Note also that resource.
Matching state token: Where there is an exact match between
the
state token in lockdiscovery property for the If header and any state token Request-URI has been included as
required. In this example the lockdiscovery property is empty which
means that there are no outstanding locks on the resource.
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8.4.5 If Header and Non-DAV Compliant Proxies
Non-DAV compliant proxies will not honor the If header, since they
will not understand
In this example, the If header, nonce, response, and HTTP requires non-understood
headers to be ignored. When communicating with HTTP/1.1 proxies,
the "Cache-Control: no-cache" request header MUST be used so as to
prevent the proxy from improperly trying to service the request from
its cache. When dealing with HTTP/1.0 proxies opaque fields have not
been calculated in the "Pragma: no-
cache" Authorization request header MUST be used for the same reason.
8.5 Lock-Token Request Header
Lock-Token = "Lock-Token" ":" Coded-URL header.
8.11 UNLOCK Method
The Lock-Token request header is used with the UNLOCK method to
identify removes the lock to be removed. The identified by the lock token in
the Lock-Token request header MUST identify a lock that contains the resource
identified by Request-URI as a member.
8.6 Overwrite Header
Overwrite = "Overwrite" ":" ("T" | "F")
The Overwrite header specifies whether from the server should overwrite Request-URI, and all other
resources included in the state of a non-null destination resource during a COPY or MOVE.
A value of "F" states that lock. If all resources which have been
locked under the server must submitted lock token can not perform be unlocked then the COPY or
MOVE operation if
UNLOCK request MUST fail.
Any DAV compliant resource which supports the state of LOCK method MUST
support the destination resource UNLOCK method.
8.11.1 Example - UNLOCK
>>Request
UNLOCK /workspace/webdav/info.doc HTTP/1.1
Host: webdav.sb.aol.com
Lock-Token: <opaquelocktoken:a515cfa4-5da4-22e1-f5b5-00a0451e6bf7>
Authorization: Digest username="ejw",
realm="ejw@webdav.sb.aol.com", nonce="...",
uri="/workspace/webdav/proposal.doc",
response="...", opaque="..."
>>Response
HTTP/1.1 204 No Content
In this example, the lock identified by the lock token
"opaquelocktoken:a515cfa4-5da4-22e1-f5b5-00a0451e6bf7" is non-null.
successfully removed from the resource
http://webdav.sb.aol.com/workspace/webdav/info.doc. If this lock
included more than just one resource, the overwrite header lock is not removed from all
resources included in a COPY or MOVE request
then the resource MUST treat the request as if it has an overwrite
header of value "T". While the Overwrite header appears to duplicate
the functionality of the If-Match: * header lock. The 204 (No Content) status code is
used instead of HTTP/1.1, If-Match
applies only to 200 (OK) because there is no response entity body.
In this example, the Request-URI, nonce, response, and opaque fields have not to the Destination of a
COPY or MOVE.
If a COPY or MOVE is not performed due to
been calculated in the value of Authorization request header.
Goland et al. [Page 50]
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9 HTTP Headers for Distributed Authoring
9.1 DAV Header
DAV = "DAV" ":" "1" ["," "2"] ["," 1#extend]
This header indicates that the Overwrite
header, resource supports the method MUST fail with a 409 Conflict status code. DAV schema and
protocol as specified. All DAV compliant resources MUST support return the Overwrite header.
8.7 Status-URI Response Header
The Status-URI response
DAV header may be used with the 102 Processing
status code to inform the client as to the status of on all OPTIONS responses.
The value is a method.
Status-URI list of all compliance classes that the resource
supports. Note that above a comma has already been added to the 2.
This is because a resource can not be level 2 compliant unless it is
also level 1 compliant. Please refer to section 15 for more details.
In general, however, support for one compliance class does not
entail support for any other.
9.2 Depth Header
Depth = "Status-URI" "Depth" ":" *(Status-Code "<" URI ">") ; Status-
Code is defined in 6.1.1 of [Fielding et al., 1997] ("0" | "1" | "infinity")
The URIs listed in the Depth header are source is used with methods executed on resources which
could potentially have been
affected by internal members to indicate whether the outstanding method.
method is to be applied only to the resource ("Depth: 0"), to the
resource and its immediate children, ("Depth: 1"), or the resource
and all its progeny ("Depth: infinity").
The status code indicates Depth header is only supported if a method's definition
explicitly provides for such support.
The following rules are the
resolution of default behavior for any method that
supports the Depth header. A method may override these defaults by
defining different behavior in its definition.
Methods which support the Depth header may choose not to support all
of the header's values and may define, on a case by case basis, the identified resource. So, for
example,
behavior of the method if a Depth header is not present. For
example, the MOVE method on a collection is outstanding only supports "Depth: infinity" and if a 102
"Processing" response with a Status-URI response
Depth header is returned,
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the included URIs not present will indicate resources that have had move
attempted act as if a "Depth: infinity"
header had been applied.
Clients MUST NOT rely upon methods executing on them and what the result was.
8.8 Timeout Request Header
TimeOut = "Timeout" ":" 1#TimeType
TimeType = ("Second-" DAVTimeOutVal | "Infinite" | Other)
DAVTimeOutVal = 1*digit
Other = Extend field-value ; See section 4.2 members of [Fielding et al.,
1997]
Clients may include Timeout headers in their LOCK requests.
However, the server is not required to honor
hierarchies in any particular order or even consider these
requests. Clients MUST NOT submit on the execution being atomic
unless the particular method explicitly provides such guarantees.
Upon execution, a Timeout request header with any method other than with a LOCK method.
A Timeout request Depth header MUST contain at least one TimeType and may
contain multiple TimeType entries. The purpose will perform as much of listing multiple
TimeType entries is
its assigned task as possible and then return a response specifying
what it was able to indicate multiple different values accomplish and value
types that are acceptable what it failed to the client. The client lists the
TimeType entries do.
So, for example, an attempt to COPY a hierarchy may result in order some
of preference.
Timeout response valuse MUST use a Second value, Infinite, or a
TimeType the client members being copied and some not.
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Any headers on a method that has indicated familiarity with. The server may
assume a client is familiar defined interaction with any TimeType submitted the
Depth header MUST be applied to all resources in a Timeout
header.
The "Second" TimeType specifies the number of seconds that will
elapse between granting scope of the lock at
method except where alternative behavior is explicitly defined. For
example, an If-Match header will have its value applied against
every resource in the server, method's scope and will cause the automatic
removal of method to
fail if the lock. The timeout value for timetype "Second" MUST
NOT be greater than 2^32-1.
The timeout counter SHOULD be restarted any time an owner header fails to match.
If a resource, source or destination, within the scope of the
lock sends a method
with a Depth header is locked in such a way as to any member prevent the
successful execution of the lock, including unsupported
methods, or methods which are unsuccessful. However method, then the lock token for that
resource MUST be refreshed if a refresh LOCK method is successfully received. submitted with the request in the If request
header.
The Depth header only specifies the timeout expires behavior of the method with
regards to internal children. If a resource does not have internal
children then the lock may Depth header MUST be lost. Specifically, if
the server wishes ignored.
Please note, however, that it is always an error to harvest the lock upon time-out, submit a value
for the server
SHOULD act as if an UNLOCK method was executed Depth header that is not allowed by the server method's definition.
Thus submitting a "Depth: 1" on a COPY, even if the resource using the lock token of the timed-out lock, performed with
its override authority. Thus logs does
not have internal members, will result in a 400 (Bad Request). The
method should be updated with fail not because the
disposition resource doesn't have internal
members, but because of the lock, notifications should be sent, etc., just as
they would be illegal value in the header.
9.3 Destination Header
Destination = "Destination" ":" absoluteURI
The Destination header specifies a destination resource for an UNLOCK request.
Servers are advised methods
such as COPY and MOVE, which take two URIs as parameters. Note that
the absoluteURI production is defined in [RFC2396].
9.4 If Header
If = "If" ":" ( 1*No-tag-list | 1*Tagged-list)
No-tag-list = List
Tagged-list = Resource 1*List
Resource = Coded-url
List = "(" 1*(["Not"](State-token | "[" entity-tag "]")) ")"
State-token = Coded-URL
Coded-URL = "<" absoluteURI ">"
The If header is intended to pay close attention have similar functionality to the values submitted
by clients, as they will be indicative of the type If-
Match header defined in section 14.25 of activity [RFC2068]. However the
client intends If
header is intended for use with any URI which represents state
information, referred to perform. For example, an applet running in as a
browser may need to lock state token, about a resource, but because of the instability resource as well
as ETags. A typical example of the environment within which the applet is running, the applet
may be turned off without warning. As a result, the applet state token is
likely to ask for a relatively small timeout value so that if lock token, and
lock tokens are the only state tokens defined in this specification.
All DAV compliant resources MUST honor the If header.
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applet dies, the lock can be quickly harvested. However, a document
management system
The If header's purpose is likely to ask for an extremely long timeout
because its user may be planning on going off-line.
A client MUST NOT assume that just because the time-out has expired
the lock has been lost.
9 Status Code Extensions to HTTP/1.1
The following status codes are added to those defined in HTTP/1.1
[Fielding et al., 1997].
9.1 102 Processing
Methods can potentially take describe a long period series of time to process,
especially methods that support the Depth header. In such cases the
client may time-out state lists. If
the connection while waiting for a response. To
prevent this state of the server may return a 102 status code to indicate resource to which the client that the server header is still processing applied does not
match any of the method.
If a method is taking longer than 20 seconds (a reasonable, but
arbitrary value) to process specified state lists then the server SHOULD return request MUST fail
with a 102
"Processing" response.
9.2 207 Multi-Status
The response provides status for multiple independent operations.
9.3 422 Unprocessable Entity
The server understands 412 (Precondition Failed). If one of the content type described state
lists matches the state of the resource then the request entity, but
was unable to process may
succeed.
Note that the contained instructions.
9.4 423 Locked
The source or destination resource of a method absoluteURI production is locked.
9.5 424 Method Failure defined in [RFC2396].
9.4.1 No-tag-list Production
The method was not executed on No-tag-list production describes a particular resource within its
scope because some part series of state tokens and
ETags. If multiple No-tag-list productions are used then one only
needs to match the state of the method's execution failed causing resource for the
entire method to be aborted. For example, if
allowed to continue.
If a command in method, due to the presence of a
PROPPATCH method fails then, at minimum, the rest of the commands
will also fail with 424 Method Failure.
9.6 425 Insufficient Space on Resource
The resource does not have sufficient space Depth or Destination header,
is applied to record the state of multiple resources then the No-tag-list production
MUST be applied to each resource after the execution of this method.
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10 Multi-Status Response
The default 207 Multi-Status response body method is a text/xml HTTP entity applied to.
9.4.1.1 Example - No-tag-list If Header
If: (<locktoken:a-write-lock-token> ["I am an ETag"]) (["I am
another ETag"])
The previous header would require that contains a single XML element called multistatus, which
contains a set any resources within the
scope of XML elements called response which contain 200,
300, 400, and 500 series status codes generated during the method
invocation. 100 series status codes SHOULD NOT must either be recorded locked with the specified lock
token and in a
response XML element.
11 XML Element Definitions
In the section below, state identified by the final line of each section gives "I am an ETag" ETag or in
the
element type declaration using state identified by the format defined second ETag "I am another ETag". To put
the matter more plainly one can think of the previous If header as
being in [Bray, Paoli,
Sperberg-McQueen, 1998]. the form (or (and <locktoken:a-write-lock-token> ["I am an
ETag"]) (and ["I am another ETag"])).
9.4.2 Tagged-list Production
The "Value" field, where present, tagged-list production scopes a list production. That is, it
specifies
futher restrictions on that the allowable contents of lists following the XML element
using BNF (i.e., resource specification only
apply to further restrict the values of a PCDATA
element).
11.1 activelock XML Element
Name: activelock
Namespace: DAV:
Purpose: Describes a lock on a resource.
<!ELEMENT activelock (lockscope, locktype, depth, owner?, timeout?,
locktoken?) >
11.1.1 depth XML Element
Name: depth
Namespace: DAV:
Purpose: The value specified resource. The scope of the depth resource
production begins with the list production immediately following the
resource production and ends with the next resource production, if
any.
When the If header used is applied to create a lock.
Value: "0" | "infinity"
<!ELEMENT depth (#PCDATA) >
11.1.2 locktoken XML Element
Name: locktoken
Namespace: DAV:
Purpose: The lock token associated with a lock.
Description: The href contains one or more opaque lock token URIs
which all refer particular resource, the Tagged-
list productions MUST be searched to determine if any of the same lock (i.e., listed
resources match the OpaqueLockToken-URI operand resource(s) for the current method. If
none of the resource productions match the current resource then the
header MUST be ignored. If one of the resource productions does
match the name of the resource under consideration then the list
productions following the resource production MUST be applied to the
resource in section 5.4).
<!ELEMENT locktoken (href+) >
11.1.3 timeout XML Element
Name: timeout
Namespace: DAV:
Purpose: The timeout associated with a lock the manner specified in the previous section.
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Value: TimeType ;Defined in section 8.8
<!ELEMENT timeout (#PCDATA) >
11.2 collection XML Element
Name: collection
Namespace: DAV:
Purpose: Identifies the associated resource as a collection.
The
resourcetype property of same URI MUST NOT appear more than once in a collection resource MUST have this value.
<!ELEMENT collection EMPTY >
11.3 href XML Element
Name: href
Namespace: DAV:
Purpose: Identifies the content of the element as production
in an If header.
9.4.2.1 Example - Tagged List If header
COPY /resource1 HTTP/1.1
Host: www.foo.bar
Destination: http://www.foo.bar/resource2
If: <http://www.foo.bar/resource1> (<locktoken:a-write-lock-token>
[W/"A weak ETag"]) (["strong ETag"])
<http://www.bar.bar/random>(["another strong ETag"])
In this example http://www.foo.bar/resource1 is being copied to
http://www.foo.bar/resource2. When the method is first applied to
http://www.foo.bar/resource1, resource1 must be in the state
specified by "(<locktoken:a-write-lock-token> [W/"A weak ETag"])
(["strong ETag"])", that is, it either must be locked with a URI.
Value: URI ; See section 3.2.1 lock
token of [Fielding et al., 1997]
<!ELEMENT href (#PCDATA)>
11.4 link XML Element
Name: link
Namespace: DAV:
Purpose: Identifies the property as "locktoken:a-write-lock-token" and have a link weak entity tag
W/"A weak ETag" or it must have a strong entity tag "strong ETag".
That is the only success condition since the resource
http://www.bar.bar/random never has the method applied to it (the
only other resource listed in the If header) and contains
http://www.foo.bar/resource2 is not listed in the
source If header.
9.4.3 not Production
Every state token or ETag is either current, and destination hence describes the
state of that link.
Description: The link XML element a resource, or is used to provide the sources not current, and
destinations does not describe the
state of a link. resource. The name boolean operation of matching a state token
or ETag to the property containing the
link XML element provides the type current state of the link. Link is a multi-
valued element, so multiple links may be resource thus resolves to a true
or false value. The not production is used together to indicate
multiple links with the same type. reverse that value.
The values in the href XML
elements inside the src and dst XML elements scope of the link XML element
MUST NOT be rejected if they point to resources which do not exist.
<!ELEMENT link (src+, dst+) >
11.4.1 dst XML Element
Name: dst
Namespace: DAV:
Purpose: Indicates production is the destination of state-token or entity-tag
immediately following it.
If: (Not <locktoken:write1> <locktoken:write2>)
When submitted with a link
Value: URI
<!ELEMENT dst (#PCDATA) >
11.4.2 src XML Element
Name: src
Namespace: DAV:
Purpose: Indicates request, this If header requires that all
operand resources must not be locked with locktoken:write1 and must
be locked with locktoken:write2.
9.4.4 Matching Function
When performing If header processing, the source definition of a link. matching
state token or entity tag is as follows.
Matching entity tag: Where the entity tag matches an entity tag
associated with that resource.
Matching state token: Where there is an exact match between the
state token in the If header and any state token on the resource.
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Value: URI
<!ELEMENT src (#PCDATA) >
11.5 lockentry XML Element
Name: lockentry
Namespace: DAV:
Purpose: Defines
9.4.5 If Header and Non-DAV Compliant Proxies
Non-DAV compliant proxies will not honor the types of locks that can If header, since they
will not understand the If header, and HTTP requires non-understood
headers to be used ignored. When communicating with HTTP/1.1 proxies,
the
resource.
<!ELEMENT lockentry (lockscope, locktype) >
11.6 lockinfo XML Element
Name: lockinfo
Namespace: DAV:
Purpose: The lockinfo XML element is "Cache-Control: no-cache" request header MUST be used with a LOCK method so as to
specify the type of lock
prevent the client wishes proxy from improperly trying to have created.
<!ELEMENT lockinfo (lockscope, locktype, owner?) >
11.7 lockscope XML Element
Name: lockscope
Namespace: DAV:
Purpose: Specifies whether a lock service the request from
its cache. When dealing with HTTP/1.0 proxies the "Pragma: no-
cache" request header MUST be used for the same reason.
9.5 Lock-Token Header
Lock-Token = "Lock-Token" ":" Coded-URL
The Lock-Token request header is an exclusive lock, or a
shared lock.
<!ELEMENT lockscope (exclusive | shared) >
11.7.1 exclusive XML Element
Name: exclusive
Namespace: DAV:
Purpose: Specifies an exclusive used with the UNLOCK method to
identify the lock
<!ELEMENT exclusive EMPTY >
11.7.2 shared XML Element
Name: shared
Namespace: DAV:
Purpose: Specifies a shared to be removed. The lock
<!ELEMENT shared EMPTY >
11.8 locktype XML Element
Name: locktype
Namespace: DAV:
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Purpose: Specifies token in the access type of Lock-Token
request header MUST identify a lock. At present, this
specification only defines one lock type, that contains the write lock.
<!ELEMENT locktype (write) >
11.8.1 write XML Element
Name: write
Namespace: DAV:
Purpose: Specifies resource
identified by Request-URI as a write lock.
<!ELEMENT write EMPTY >
11.9 multistatus XML Element
Name: multistatus
Namespace: DAV:
Purpose: Contains multiple response messages.
Description: member.
The responsedescription at the top level Lock-Token response header is used with the LOCK method to
provide a general message describing
indicate the overarching nature lock token created as a result of a successful LOCK
request to create a new lock.
9.6 Overwrite Header
Overwrite = "Overwrite" ":" ("T" | "F")
The Overwrite header specifies whether the
response. If this server should overwrite
the state of a non-null destination resource during a COPY or MOVE.
A value is available an application may use it
instead of presenting "F" states that the individual response descriptions contained
within server must not perform the responses.
<!ELEMENT multistatus (response+, responsedescription?) >
11.9.1 response XML Element
Name: response
Namespace: DAV:
Purpose: Holds a single response describing COPY or
MOVE operation if the effect state of the destination resource is non-null.
If the overwrite header is not included in a
method on COPY or MOVE request
then the resource and/or its properties.
Description: A particular href MUST NOT appear more than once treat the request as if it has an overwrite
header of value "T". While the
child Overwrite header appears to duplicate
the functionality of the If-Match: * header of HTTP/1.1, If-Match
applies only to the Request-URI, and not to the Destination of a response XML element under
COPY or MOVE.
If a multistatus XML element.
This requirement COPY or MOVE is necessary in order not performed due to keep processing costs for the value of the Overwrite
header, the method MUST fail with a 412 (Precondition Failed) status
code.
All DAV compliant resources MUST support the Overwrite header.
9.7 Status-URI Response Header
The Status-URI response header may be used with the 102 (Processing)
status code to linear time. Essentially, this prevents having to
search in order inform the client as to group together all the responses by href. There
are, however, no requirements regarding ordering based on href
values.
<!ELEMENT response (href, ((href*, status)|(propstat+)),
responsedescription?) >
11.9.1.1 propstat XML Element
Name: propstat
Namespace: DAV:
Purpose: Groups together a prop and status element that is
associated with of a particular href element.
Description: method.
Status-URI = "Status-URI" ":" *(Status-Code Coded-URL) ; Status-Code
is defined in 6.1.1 of [RFC2068]
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The propstat XML element MUST contain one prop XML
element and one status XML element. The contents of the prop XML
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element MUST only list URIs listed in the names of properties to header are source resources which have been
affected by the result
in the status element applies.
<!ELEMENT propstat (prop, status) >
11.9.1.2 status XML Element
Name: status
Namespace: DAV:
Purpose: Holds a single HTTP status-line
Value: status-line ;status-line defined in [Fielding et al.,
1997]
<!ELEMENT outstanding method. The status (#PCDATA) >
11.9.2 responsedescription XML Element
Name: responsedescription
Namespace: DAV:
Purpose: Contains a message that can be displayed to the user
explaining code indicates the nature
resolution of the response.
Description: This XML element provides information suitable to be
presented to a user.
<!ELEMENT responsedescription (#PCDATA) >
11.10 owner XML Element
Name: owner
Namespace: DAV:
Purpose: Provides information about method on the principal taking out a
lock.
Description: The owner XML element provides information sufficient identified resource. So, for either directly contacting a principal (such as
example, if a telephone
number or Email URI), or for discovering the principal (such as the
URL of MOVE method on a homepage) who owns collection is outstanding and a lock.
<!ELEMENT owner ANY>
11.11 prop XML element
Name: prop
Namespace: DAV:
Purpose: Contains properties related to 102
(Processing) response with a resource.
Description: The prop XML element Status-URI response header is a generic container for
properties defined returned,
the included URIs will indicate resources that have had move
attempted on resources. All elements inside a prop XML
element MUST define properties related to them and what the resource. No other
elements may be used inside of a prop element.
<!ELEMENT prop ANY>
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11.12 propertybehavior XML element
Name: propertybehavior
Namespace: DAV:
Purpose: Specifies how properties are handled during a COPY or
MOVE.
Description: The propertybehavior XML element specifies how
properties are handled during a COPY or MOVE. If this XML element
is not included result was.
9.8 Timeout Request Header
TimeOut = "Timeout" ":" 1#TimeType
TimeType = ("Second-" DAVTimeOutVal | "Infinite" | Other)
DAVTimeOutVal = 1*digit
Other = Extend field-value ; See section 4.2 of [RFC2068]
Clients may include Timeout headers in the request body then their LOCK requests.
However, the server is expected not required to
act as defined by the default property handling behavior of the
associated method. All WebDAV compliant resources honor or even consider these
requests. Clients MUST support the
propertybehavior XML element.
<!ELEMENT propertybehavior (omit | keepalive) >
11.12.1 keepalive XML element
Name: keepalive
Namespace: DAV:
Purpose: Specifies requirements for the copying/moving of live
properties.
Description: If NOT submit a list Timeout request header with any
method other than a LOCK method.
A Timeout request header MUST contain at least one TimeType and may
contain multiple TimeType entries. The purpose of URIs listing multiple
TimeType entries is included as the to indicate multiple different values and value of keepalive
then the named properties MUST be "live" after they
types that are copied
(moved) acceptable to the destination resource client. The client lists the
TimeType entries in order of preference.
Timeout response valuse MUST use a COPY (or MOVE). If Second value, Infinite, or a
TimeType the
value "*" client has indicated familiarity with. The server may
assume a client is given for the keepalive XML element, this designates familiar with any TimeType submitted in a Timeout
header.
The "Second" TimeType specifies the number of seconds that all live properties on will
elapse between granting of the source resource MUST be live on lock at the
destination. If server, and the requirements specified by automatic
removal of the keepalive element
can not lock. The timeout value for timetype "Second" MUST
NOT be honored then greater than 2^32-1.
The timeout counter SHOULD be restarted any time an owner of the
lock sends a method to any member of the lock, including unsupported
methods, or methods which are unsuccessful. However the lock MUST fail with
be refreshed if a 412 Precondition
Failed. All DAV compliant resources MUST support refresh LOCK method is successfully received.
If the keepalive XML
element for use with timeout expires then the COPY and MOVE methods.
Value: "*" ; #PCDATA value can only lock may be "*"
<!ELEMENT keepalive (#PCDATA | href+) >
11.12.2 omit XML element
Name: omit
Namespace: DAV:
Purpose: The omit XML element instructs lost. Specifically, if
the server that it should
use best effort to copy properties but a failure wishes to copy a property
MUST NOT cause harvest the method to fail.
Description: The default behavior for a COPY or MOVE is to copy/move
all properties or fail lock upon time-out, the method. In certain circumstances, such server
SHOULD act as when a if an UNLOCK method was executed by the server copies a on the
resource over another protocol such as
FTP, it may not be possible to copy/move using the properties associated
with lock token of the resource. timed-out lock, performed with
its override authority. Thus any attempt to copy/move over FTP logs should be updated with the
disposition of the lock, notifications should be sent, etc., just as
they would
always have to fail because properties could not be moved over, even for an UNLOCK request.
Servers are advised to pay close attention to the values submitted
by clients, as dead properties. All DAV compliant resources MUST support they will be indicative of the
omit XML element on COPY/MOVE methods.
<!ELEMENT omit EMPTY > type of activity the
client intends to perform. For example, an applet running in a
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11.13 propertyupdate XML element
Name: propertyupdate
Namespace: DAV:
Purpose: Contains a request
browser may need to alter the properties on a
resource.
Description: This XML element is lock a container for resource, but because of the information
required to modify instability
of the properties on environment within which the resource. This XML element applet is multi-valued.
<!ELEMENT propertyupdate (remove | set)+ >
11.13.1 remove XML element
Name: remove
Namespace: DAV:
Purpose: Lists running, the DAV properties to applet
may be removed from turned off without warning. As a resource.
Description: Remove instructs result, the applet is
likely to ask for a relatively small timeout value so that if the properties specified in prop
should be removed. Specifying
applet dies, the removal of lock can be quickly harvested. However, a property that does
not exist document
management system is not likely to ask for an error. All the XML elements in a prop XML
element inside of a remove XML element MUST extremely long timeout
because its user may be empty, as only planning on going off-line.
A client MUST NOT assume that just because the
names of properties time-out has expired
the lock has been lost.
10 Status Code Extensions to be removed HTTP/1.1
The following status codes are required.
<!ELEMENT remove (prop) >
11.13.2 set XML element
Name: set
Namespace: DAV:
Purpose: Lists the DAV property values added to be set for a resource.
Description: those defined in HTTP/1.1
[RFC2068].
10.1 102 Processing
The set XML element MUST contain 102 (Processing) status code is an interim response used to
inform the client that the server has accepted the complete request,
but has not yet completed it. This status code SHOULD only be sent
when the server has a prop XML
element. The elements contained by reasonable expectation that the prop XML element inside request will
take significant time to complete. As guidance, if a method is
taking longer than 20 seconds (a reasonable, but arbitrary value) to
process the
set XML element server SHOULD return a 102 (Processing) response. The
server MUST specify send a final response after the name and value request has been
completed.
Methods can potentially take a long period of properties time to process,
especially methods that
are set on support the Request-URI. If Depth header. In such cases the
client may time-out the connection while waiting for a property already exists then its
value is replaced.
<!ELEMENT set (prop) >
11.14 propfind XML Element
Name: propfind
Namespace: DAV:
Purpose: Specifies response. To
prevent this the properties to be returned from server may return a PROPFIND 102 (Processing) status code to
indicate to the client that the server is still processing the
method. Two special elements are specified
10.2 207 Multi-Status
The 207 (Multi-Status) status code provides status for use with propfind,
allprop and propname. If prop is used inside propfind it MUST only
contain property names, not values.
<!ELEMENT propfind (allprop | propname | prop) > multiple
independent operations (see section 11 for more information).
10.3 422 Unprocessable Entity
The 422 (Unprocessable Entity) status code means the server
understands the content type of the request entity (hence a
415(Unsupported Media Type) status code is inappropriate), and the
syntax of the request entity is correct (thus a 400 (Bad Request)
status code is inappropriate) but was unable to process the
contained instructions. For example, this error condition may occur
if an XML request body contains well-formed (i.e., syntactically
correct), but semantically erroneous XML instructions.
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11.14.1 allprop XML Element
Name: allprop
Namespace: DAV:
Purpose:
10.4 423 Locked
The allprop XML element specifies 423 (Locked) status code means the source or destination
resource of a method is locked.
10.5 424 Failed Dependency
The 424 (Failed Dependency) status code means that all property
names and values the method could
not be performed on the resource are to be returned.
<!ELEMENT allprop EMPTY >
11.14.2 propname XML Element
Name: propname
Namespace: DAV:
Purpose: The propname XML element specifies because the requested action
depended on another action and that only action failed. For example, if
a list command in a PROPPATCH method fails then, at minimum, the rest of
property names
the commands will also fail with 424 (Failed Dependency).
10.6 507 Insufficient Storage
The 507 (Insufficient Storage) status code means the method could
not be performed on the resource because the server is unable to be returned.
<!ELEMENT propname EMPTY >
12 DAV Properties
For DAV properties,
store the name of representation needed to successfully complete the property
request. This condition is also considered to be temporary. If the same as
request which received this status code was the
name result of a user
action, the request MUST NOT be repeated until it is requested by a
separate user action.
11 Multi-Status Response
The default 207 (Multi-Status) response body is a text/xml or
application/xml HTTP entity that contains a single XML element
called multistatus, which contains a set of XML elements called
response which contain 200, 300, 400, and 500 series status codes
generated during the method invocation. 100 series status codes
SHOULD NOT be recorded in a response XML element.
12 XML Element Definitions
In the XML element that contains its value. In the section below, the final line of each section gives the
element type declaration using the format defined in [Bray, Paoli, Sperberg-
McQueen, 1998]. [REC-XML]. The
"Value" field, where present, specifies futher restrictions on the
allowable contents of the XML element using BNF (i.e., to further
restrict the values of a PCDATA element).
12.1 creationdate Property activelock XML Element
Name: creationdate activelock
Namespace: DAV:
Purpose: Records the time and date the resource was created.
Value: date-time ; See Appendix 2
Description: The creationdate property should be defined Describes a lock on all DAV
compliant resources. If present, it contains a timestamp of the
moment when the resource was created (i.e., the moment it had non-
null state). resource.
<!ELEMENT creationdate (#PCDATA) activelock (lockscope, locktype, depth, owner?, timeout?,
locktoken?) >
12.2 displayname Property
Name: displayname
Namespace: DAV:
Purpose: Provides a name for the resource that is suitable for
presentation to a user.
Description: The displayname property should be defined on all DAV
compliant resources. If present, the property contains a
description of the resource that is suitable for presentation to a
user.
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12.1.1 depth XML Element
Name: depth
Namespace: DAV:
Purpose: The value of the Depth header.
Value: "0" | "1" | "infinity"
<!ELEMENT displayname depth (#PCDATA) >
12.3 getcontentlanguage Property
12.1.2 locktoken XML Element
Name: getcontentlanguage locktoken
Namespace: DAV:
Purpose: Contains the Content-Language header returned by The lock token associated with a GET
without accept headers lock.
Description: The getcontentlanguage property MUST be defined on any
DAV compliant resource that returns href contains one or more opaque lock token URIs
which all refer to the Content-Language header on a
GET.
Value: language-tag ;language-tag is defined same lock (i.e., the OpaqueLockToken-URI
production in section 14.13
of [Fielding et al., 1997] 6.4).
<!ELEMENT getcontentlanguage (#PCDATA) locktoken (href+) >
12.4 getcontentlength Property
12.1.3 timeout XML Element
Name: getcontentlength timeout
Namespace: DAV:
Purpose: Contains the Content-Length header returned by a GET
without accept headers.
Description: The getcontentlength property MUST be defined on any
DAV compliant resource that returns the Content-Length header in
response to timeout associated with a GET. lock
Value: content-length ; see TimeType ;Defined in section 14.14 of [Fielding et al.,
1997] 9.8
<!ELEMENT getcontentlength timeout (#PCDATA) >
12.5 getcontenttype Property
12.2 collection XML Element
Name: getcontenttype collection
Namespace: DAV:
Purpose: Contains Identifies the Content-Type header returned by a GET
without accept headers.
Description: This getcontenttype property MUST be defined on any DAV
compliant associated resource that returns the Content-Type header in response
to as a GET.
Value: media-type ; defined in section 3.7 collection. The
resourcetype property of [Fielding et
al., 1997] a collection resource MUST have this value.
<!ELEMENT getcontenttype (#PCDATA) collection EMPTY >
12.6 getetag Property
12.3 href XML Element
Name: getetag href
Namespace: DAV:
Purpose: Contains the ETag header returned by a GET without
accept headers.
Description: Note that the ETag on a resource may reflect changes in
any part of Identifies the state content of the resource, not necessarily just element as a change URI.
Value: URI ; See section 3.2.1 of [RFC2068]
<!ELEMENT href (#PCDATA)>
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to the response to
12.4 link XML Element
Name: link
Namespace: DAV:
Purpose: Identifies the GET method. For example, a change to property as a
resource's access permissions may cause link and contains the ETag to change. The
getetag property MUST be defined on any DAV compliant resource
source and destination of that
returns the Etag header in response link.
Description: The link XML element is used to provide the sources and
destinations of a GET.
Value: entity-tag ; defined in section 3.11 link. The name of [Fielding et
al., 1997]
<!ELEMENT getetag (#PCDATA) >
12.7 getlastmodified Property
Name: getlastmodified
Namespace: DAV:
Purpose: Contains the Last-Modified header returned by a GET
method without accept headers.
Description: Note that property containing the last-modified date on a resource may
reflect changes in any part of
link XML element provides the state type of the resource, not
necessarily just link. Link is a change to the response multi-
valued element, so multiple links may be used together to indicate
multiple links with the GET method. For
example, a change same type. The values in a property may cause the last-modified date to
change. The getlastmodified property href XML
elements inside the src and dst XML elements of the link XML element
MUST NOT be defined on any DAV
compliant resource that returns the Last-Modified header in response rejected if they point to resources which do not exist.
<!ELEMENT link (src+, dst+) >
12.4.1 dst XML Element
Name: dst
Namespace: DAV:
Purpose: Indicates the destination of a GET. link
Value: HTTP-date ; defined in section 3.3.1 of [Fielding et
al., 1997] URI
<!ELEMENT getlastmodified dst (#PCDATA) >
12.8 lockdiscovery Property
12.4.2 src XML Element
Name: lockdiscovery src
Namespace: DAV:
Purpose: Describes Indicates the active locks on a resource
Description: The lockdiscovery property returns a listing source of who has a lock, what type link.
Value: URI
<!ELEMENT src (#PCDATA) >
12.5 lockentry XML Element
Name: lockentry
Namespace: DAV:
Purpose: Defines the types of lock he has, the timeout type and the time
remaining on the timeout, and locks that can be used with the associated lock token.
resource.
<!ELEMENT lockentry (lockscope, locktype) >
12.6 lockinfo XML Element
Name: lockinfo
Namespace: DAV:
Purpose: The server lockinfo XML element is free used with a LOCK method to withhold any or all
specify the type of this information if lock the requesting
principal does not have sufficient access rights client wishes to see the
requested data. have created.
<!ELEMENT lockdiscovery (activelock)* lockinfo (lockscope, locktype, owner?) >
12.8.1 Example - Retrieving the lockdiscovery Property
>>Request
PROPFIND /container/ HTTP/1.1
Host: www.foo.bar
Content-Length: xxxx
Content-Type: text/xml
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
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<D:propfind>
<D:prop><D:lockdiscovery/></D:prop>
</D:propfind>
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml
Content-Length: xxxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:multistatus>
<D:response>
<D:href>http://www.foo.bar/container/</D:href>
<D:propstat>
<D:prop>
<D:lockdiscovery>
<D:activelock>
<D:locktype><D:write/></D:locktype>
<D:lockscope><D:exclusive/></D:lockscope>
<D:depth>0</D:depth>
<D:owner>Jane Smith</D:owner>
<D:timeout>Infinite</D:timeout>
<D:locktoken>
<D:href>
opaquelocktoken:f81de2ad-7f3d-a1b2-4f3c-00a0c91a9d76
</D:href>
</D:locktoken>
</D:activelock>
</D:lockdiscovery>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
This resource has
12.7 lockscope XML Element
Name: lockscope
Namespace: DAV:
Purpose: Specifies whether a single exclusive write lock on it, with is an
infinite timeout.
12.9 resourcetype Property exclusive lock, or a
shared lock.
<!ELEMENT lockscope (exclusive | shared) >
12.7.1 exclusive XML Element
Name: resourcetype exclusive
Namespace: DAV:
Purpose: Specifies the nature of the resource.
Description: The resourcetype property MUST be defined on all DAV
compliant resources. The default value is empty. an exclusive lock
<!ELEMENT resourcetype ANY exclusive EMPTY >
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12.10 source Property
12.7.2 shared XML Element
Name: source shared
Namespace: DAV:
Purpose: The destination of Specifies a shared lock
<!ELEMENT shared EMPTY >
12.8 locktype XML Element
Name: locktype
Namespace: DAV:
Purpose: Specifies the source link identifies the
resource that contains the unprocessed source access type of a lock. At present, this
specification only defines one lock type, the link's source. write lock.
<!ELEMENT locktype (write) >
12.8.1 write XML Element
Name: write
Namespace: DAV:
Purpose: Specifies a write lock.
<!ELEMENT write EMPTY >
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12.9 multistatus XML Element
Name: multistatus
Namespace: DAV:
Purpose: Contains multiple response messages.
Description: The source of responsedescription at the link (src) top level is typically used to
provide a general message describing the URI overarching nature of the output resource on which the link is defined, and there
response. If this value is
typically only one destination (dst) available an application may use it
instead of presenting the link, which is individual response descriptions contained
within the URI
where responses.
<!ELEMENT multistatus (response+, responsedescription?) >
12.9.1 response XML Element
Name: response
Namespace: DAV:
Purpose: Holds a single response describing the unprocessed source effect of the a
method on resource may be accessed. When and/or its properties.
Description: A particular href MUST NOT appear more than one link destination exists, once as the
child of a response XML element under a multistatus XML element.
This requirement is necessary in order to keep processing costs for
a response to linear time. Essentially, this specification asserts prevents having to
search in order to group together all the responses by href. There
are, however, no
policy requirements regarding ordering based on ordering. href
values.
<!ELEMENT source (link)* response (href, ((href*, status)|(propstat+)),
responsedescription?) >
12.10.1 Example - A source Property
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.foocorp.com/Project/" prefix="F" ?>
<D:prop>
<D:source>
<D:link>
<F:projfiles>Source</F:projfiles>
<D:src>http://foo.bar/program</D:src>
<D:dst>http://foo.bar/src/main.c</D:dst>
</D:link>
<D:link>
<F:projfiles>Library</F:projfiles>
<D:src>http://foo.bar/program</D:src>
<D:dst>http://foo.bar/src/main.lib</D:dst>
</D:link>
<D:link>
<F:projfiles>Makefile</F:projfiles>
<D:src>http://foo.bar/program</D:src>
<D:dst>http://foo.bar/src/makefile</D:dst>
</D:link>
</D:source>
</D:prop>
In this example the resource http://foo.bar/program has
12.9.1.1 propstat XML Element
Name: propstat
Namespace: DAV:
Purpose: Groups together a source
property that contains three links. Each link contains three
elements, two of which, src prop and dst, are part of the DAV schema
defined in this document, status element that is
associated with a particular href element.
Description: The propstat XML element MUST contain one prop XML
element and one which is defined by status XML element. The contents of the schema
http://www.foocorp.com/project/ (Source, Library, and Makefile). A
client which prop XML
element MUST only implements the elements in the DAV spec will not
understand the foocorp elements and will ignore them, thus seeing
the expected source and destination links. An enhanced client may
know about list the foocorp elements and be able names of properties to present the user with
additional information about which the links. This example demonstrates result
in the power of XML markup, allowing status element values to be enhanced
without breaking older clients. applies.
<!ELEMENT propstat (prop, status, responsedescription?) >
12.9.1.2 status XML Element
Name: status
Namespace: DAV:
Purpose: Holds a single HTTP status-line
Value: status-line ;status-line defined in [RFC2068]
<!ELEMENT status (#PCDATA) >
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12.11 supportedlock Property
12.9.2 responsedescription XML Element
Name: supportedlock responsedescription
Namespace: DAV:
Purpose: To provide Contains a listing of message that can be displayed to the lock capabilities supported
by user
explaining the resource.
Description: The supportedlock property of a resource returns a
listing nature of the combinations of scope and access types which may response.
Description: This XML element provides information suitable to be
specified in
presented to a lock request on the resource. Note that the actual
contents are themselves controlled by access controls so a server is
not required to provide information the client is not authorized to
see. user.
<!ELEMENT supportedlock (lockentry)* responsedescription (#PCDATA) >
12.11.1 Example - Retrieving the supportedlock Property
>>Request
PROPFIND /container/ HTTP/1.1
Host: www.foo.bar
Content-Length: xxxx
Content-Type: text/xml
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:propfind>
<D:prop><D:supportedlock/></D:prop>
</D:propfind>
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>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml
Content-Length: xxxxx
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:multistatus>
<D:response>
<D:href>http://www.foo.bar/container/</D:href>
<D:propstat>
<D:prop>
<D:supportedlock>
<D:lockentry>
<D:lockscope><D:exclusive/></D:lockscope>
<D:locktype><D:write/></D:locktype>
</D:lockentry>
<D:lockentry>
<D:lockscope><D:shared/></D:lockscope>
<D:locktype><D:write/></D:locktype>
</D:lockentry>
</D:supportedlock>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
13 DAV
12.10 owner XML Processing Instructions
All DAV compliant resources MUST ignore any unknown Element
Name: owner
Namespace: DAV:
Purpose: Provides information about the principal taking out a
lock.
Description: The owner XML element and
all its children encountered while processing provides information sufficient
for either directly contacting a DAV method that uses
XML principal (such as its command language.
This restriction also applies to a telephone
number or Email URI), or for discovering the processing, by clients, principal (such as the
URL of DAV
property values where unknown a homepage) who owns a lock.
<!ELEMENT owner ANY>
12.11 prop XML elements SHOULD be ignored unless
the property's schema declares otherwise.
This restriction does not apply element
Name: prop
Namespace: DAV:
Purpose: Contains properties related to setting dead DAV a resource.
Description: The prop XML element is a generic container for
properties defined on
the server where the server MUST record unknown resources. All elements inside a prop XML elements.
Additionally, this restriction does not apply
element MUST define properties related to the use of XML
where XML happens to resource. No other
elements may be the content type used inside of a prop element.
<!ELEMENT prop ANY>
12.12 propertybehavior XML element
Name: propertybehavior
Namespace: DAV:
Purpose: Specifies how properties are handled during a COPY or
MOVE.
Description: The propertybehavior XML element specifies how
properties are handled during a COPY or MOVE. If this XML element
is not included in the entity body, for
example, when used request body then the server is expected to
act as defined by the body default property handling behavior of a PUT.
14 DAV Compliance Classes
A DAV the
associated method. All WebDAV compliant resource can choose from two classes of compliance.
A client can discover resources MUST support the compliance classes of a resource by
propertybehavior XML element.
<!ELEMENT propertybehavior (omit | keepalive) >
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executing OPTIONS on the resource, and examining
12.12.1 keepalive XML element
Name: keepalive
Namespace: DAV:
Purpose: Specifies requirements for the "DAV" header
which copying/moving of live
properties.
Description: If a list of URIs is returned.
Since this document describes extensions to included as the HTTP/1.1 protocol,
minimally all DAV compliant resources, clients, and proxies value of keepalive
then the named properties MUST be
compliant with [Fielding et al., 1997].
Compliance classes "live" after they are not necessarily sequential. A copied
(moved) to the destination resource that
is class 2 compliant must also be class 1 compliant; but if
additional compliance classes are defined later, of a resource that COPY (or MOVE). If the
value "*" is
class 1, 2, and 4 compliant might not be class 3 compliant. Also
note given for the keepalive XML element, this designates
that identifiers other than numbers may be used as compliance
class identifiers.
14.1 Class 1
A class 1 compliant resource MUST meet all "MUST" requirements in all sections of this document.
Class 1 compliant resources MUST return, at minimum, the value "1"
in the DAV header live properties on all responses to the OPTIONS method.
14.2 Class 2
A class 2 compliant source resource MUST meet all class 1 requirements and
support the LOCK method, be live on the supportedlock property,
destination. If the
lockdiscovery property, requirements specified by the Time-Out response header and keepalive element
can not be honored then the Lock-
Token request header. A class "2" method MUST fail with a 412
(Precondition Failed). All DAV compliant resource SHOULD also resources MUST support the Time-Out request header and the owner
keepalive XML element.
Class 2 compliant resources MUST return, at minimum, element for use with the values "1" COPY and "2" in MOVE methods.
Value: "*" ; #PCDATA value can only be "*"
<!ELEMENT keepalive (#PCDATA | href+) >
12.12.2 omit XML element
Name: omit
Namespace: DAV:
Purpose: The omit XML element instructs the DAV header on all responses server that it should
use best effort to copy properties but a failure to copy a property
MUST NOT cause the method to fail.
Description: The default behavior for a COPY or MOVE is to copy/move
all properties or fail the OPTIONS method.
15 Internationalization Considerations In certain circumstances, such
as when a server copies a resource over another protocol such as
FTP, it may not be possible to copy/move the realm of internationalization, this specification complies properties associated
with the IETF Character Set Policy [Alvestrand, 1998]. In this
specification, human-readable fields can be found either in the
value of a property, or in an error message returned in a response
entity body. In both cases, resource. Thus any attempt to copy/move over FTP would
always have to fail because properties could not be moved over, even
as dead properties. All DAV compliant resources MUST support the human-readable content is encoded
using XML, which has explicit provisions for character set tagging
and encoding, and requires that
omit XML processors read element on COPY/MOVE methods.
<!ELEMENT omit EMPTY >
12.13 propertyupdate XML elements
encoded, at minimum, using the UTF-8 [Yergeau, 1998] encoding of element
Name: propertyupdate
Namespace: DAV:
Purpose: Contains a request to alter the
ISO 10646 multilingual plane. properties on a
resource.
Description: This XML also provides element is a language tagging capability container for specifying the
language of information
required to modify the contents of a particular XML element. XML uses
either IANA registered language tags (see RFC 1766, [Alvestrand,
1995]) or ISO 639 language tags [ISO-639] in properties on the "xml:lang"
attribute of an resource. This XML element to identify the language of its content
and attributes.
is multi-valued.
<!ELEMENT propertyupdate (remove | set)+ >
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WebDAV applications MUST support
12.13.1 remove XML element
Name: remove
Namespace: DAV:
Purpose: Lists the character set tagging,
character set encoding, and DAV properties to be removed from a resource.
Description: Remove instructs that the language tagging functionality properties specified in prop
should be removed. Specifying the removal of a property that does
not exist is not an error. All the XML specification.
Names used within this specification fall into three categories:
names of protocol elements such as methods and headers, names of in a prop XML
elements, and names of properties. Naming
element inside of protocol elements
follows a remove XML element MUST be empty, as only the precedent of HTTP, using English
names encoded in
USASCII for methods and headers. Since these protocol elements are
not visible of properties to users, and be removed are in fact simply long token identifiers,
they do not need to support encoding in multiple character sets.
Similarly, though the names of required.
<!ELEMENT remove (prop) >
12.13.2 set XML elements used in this
specification are English names encoded in UTF-8, these names are
not visible to element
Name: set
Namespace: DAV:
Purpose: Lists the user, and hence do not need DAV property values to support multiple
character be set encodings.
The name of a property defined on a resource is for a URI. Although
some applications (e.g., resource.
Description: The set XML element MUST contain only a generic property viewer) will display
property URIs directly to their users, it is expected that prop XML
element. The elements contained by the prop XML element inside the
typical application will use a fixed
set of properties, and will
provide a mapping from XML element MUST specify the property name URI to a human-readable
field when displaying and value of properties that
are set on the property name to Request-URI. If a user. It property already exists then its
value is only replaced. Language tagging information in the case where property's
value (in the "xml:lang" attribute, if present) MUST be persistently
stored along with the property, and MUST be subsequently retrievable
using PROPFIND.
<!ELEMENT set of (prop) >
12.14 propfind XML Element
Name: propfind
Namespace: DAV:
Purpose: Specifies the properties is not known ahead of time that
an application need display a property name URI to be returned from a user. We
recommend PROPFIND
method. Two special elements are specified for use with propfind,
allprop and propname. If prop is used inside propfind it MUST only
contain property names, not values.
<!ELEMENT propfind (allprop | propname | prop) >
12.14.1 allprop XML Element
Name: allprop
Namespace: DAV:
Purpose: The allprop XML element specifies that applications provide human-readable all property
names
wherever feasible.
For error reporting, we follow the convention of HTTP/1.1 status
codes, including with each status code a short, English description
of the code (e.g., 423 Locked). While the possibility exists that a
poorly crafted user agent would display this message to a user,
internationalized applications will ignore this message, and display
an appropriate message in values on the user's language and character set.
Since interoperation of clients and servers does not require locale
information, this specification does not specify any mechanism for
transmission of this information.
16 Security Considerations
This section is provided to detail issues concerning security
implications of which WebDAV applications need resource are to be aware.
All of the security considerations of HTTP/1.1 also apply to WebDAV.
In addition, the security risks inherent in remote authoring require
stronger authentication technology, introduce several new privacy
concerns, and may increase the hazards from poor server design.
These issues are detailed below.
16.1 Authentication of Clients returned.
<!ELEMENT allprop EMPTY >
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Due to their emphasis
12.14.2 propname XML Element
Name: propname
Namespace: DAV:
Purpose: The propname XML element specifies that only a list of
property names on authoring, WebDAV servers need to use
authentication technology the resource is to protect not just access to a network
resource, but be returned.
<!ELEMENT propname EMPTY >
13 DAV Properties
For DAV properties, the integrity name of the resource property is also the same as well. Furthermore, the introduction
name of locking functionality requires support for
authentication.
A password sent the XML element that contains its value. In the section
below, the final line of each section gives the element type
declaration using the format defined in [REC-XML]. The "Value"
field, where present, specifies futher restrictions on the clear over an insecure channel is an
inadequate means for protecting allowable
contents of the accessibility and integrity XML element using BNF (i.e., to further restrict the
values of a
resource as PCDATA element).
13.1 creationdate Property
Name: creationdate
Namespace: DAV:
Purpose: Records the password may time and date the resource was created.
Value: date-time ; See Appendix 2
Description: The creationdate property should be intercepted. Since Basic
authentication for HTTP/1.1 performs essentially clear text
transmission defined on all DAV
compliant resources. If present, it contains a timestamp of the
moment when the resource was created (i.e., the moment it had non-
null state).
<!ELEMENT creationdate (#PCDATA) >
13.2 displayname Property
Name: displayname
Namespace: DAV:
Purpose: Provides a password, Basic authentication MUST NOT be used name for the resource that is suitable for
presentation to
authenticate a WebDAV client to user.
Description: The displayname property should be defined on all DAV
compliant resources. If present, the property contains a server unless
description of the connection resource that is
secure. Furthermore, suitable for presentation to a
user.
<!ELEMENT displayname (#PCDATA) >
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13.3 getcontentlanguage Property
Name: getcontentlanguage
Namespace: DAV:
Purpose: Contains the
connection is secure. Examples of secure connections include a
Transport Layer Security (TLS) connection, or Content-Language header returned by a connection over GET
without accept headers
Description: The getcontentlanguage property MUST be defined on any
DAV compliant resource that returns the Content-Language header on a
network which
GET.
Value: language-tag ;language-tag is physically secure, for example, an isolated network defined in section 14.13
of [RFC2068]
<!ELEMENT getcontentlanguage (#PCDATA) >
13.4 getcontentlength Property
Name: getcontentlength
Namespace: DAV:
Purpose: Contains the Content-Length header returned by a building with restricted access.
WebDAV applications GET
without accept headers.
Description: The getcontentlength property MUST support the Digest authentication scheme
[Franks et al., 1997]. Since Digest authentication verifies be defined on any
DAV compliant resource that
both parties returns the Content-Length header in
response to a communication know a shared secret, GET.
Value: content-length ; see section 14.14 of [RFC2068]
<!ELEMENT getcontentlength (#PCDATA) >
13.5 getcontenttype Property
Name: getcontenttype
Namespace: DAV:
Purpose: Contains the Content-Type header returned by a password, GET
without having to send accept headers.
Description: This getcontenttype property MUST be defined on any DAV
compliant resource that secret in the clear, Digest
authentication avoids returns the security problems inherent Content-Type header in Basic
authentication while providing response
to a level of authentication which is
useful GET.
Value: media-type ; defined in a wide range of scenarios.
16.2 Denial of Service
Denial of service attacks are of special concern to WebDAV servers.
WebDAV plus HTTP enables denial of service attacks on every part section 3.7 of
a system's resources.
The underlying storage can be attacked by PUTting extremely large
files.
Asking for recursive operations on large collections can attack
processing time.
Making multiple pipelined requests on multiple connections can
attack network connections.
WebDAV servers need to be aware of the possibility of a denial of
service attack at all levels.
16.3 Security through Obscurity
WebDAV provides, through the PROPFIND method, a mechanism for
listing [RFC2068]
<!ELEMENT getcontenttype (#PCDATA) >
13.6 getetag Property
Name: getetag
Namespace: DAV:
Purpose: Contains the member resources of ETag header returned by a collection. This greatly
diminishes the effectiveness of security or privacy techniques that
rely only GET without
accept headers.
Description: The getetag property MUST be defined on any DAV
compliant resource that returns the difficulty of discovering the names of network
resources. Users Etag header.
Value: entity-tag ; defined in section 3.11 of WebDAV servers are encouraged to use access [RFC2068]
<!ELEMENT getetag (#PCDATA) >
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control techniques to prevent unwanted access to resources, rather
than depending on
13.7 getlastmodified Property
Name: getlastmodified
Namespace: DAV:
Purpose: Contains the relative obscurity of their resource names.
16.4 Privacy Issues Connected to Locks
When submitting Last-Modified header returned by a lock request GET
method without accept headers.
Description: Note that the last-modified date on a user agent resource may also submit an owner
XML field giving contact information for
reflect changes in any part of the person taking out state of the
lock (for those cases where a person, rather than resource, not
necessarily just a robot, is taking
out change to the lock). This contact information is stored response to the GET method. For
example, a change in a lockdiscovery property on may cause the resource, and can be used by other collaborators to
begin negotiation over access last-modified date to
change. The getlastmodified property MUST be defined on any DAV
compliant resource that returns the resource. However, Last-Modified header in many
cases this contact information can be very private, and should not
be widely disseminated. Servers SHOULD limit read access response
to a GET.
Value: HTTP-date ; defined in section 3.3.1 of [RFC2068]
<!ELEMENT getlastmodified (#PCDATA) >
13.8 lockdiscovery Property
Name: lockdiscovery
Namespace: DAV:
Purpose: Describes the active locks on a resource
Description: The lockdiscovery property as appropriate. Furthermore, user agents
SHOULD provide control over whether contact information is sent at
all, and if contact information is sent, control over exactly what
information is sent.
16.5 Privacy Issues Connected to Properties
Since property values are typically used to hold information such as
the author returns a listing of who has
a document, there is lock, what type of lock he has, the possibility that privacy
concerns could arise stemming from widespread access to a resource's
property data. To reduce timeout type and the risk of inadvertent release of private
information via properties, servers are encouraged to develop access
control mechanisms that separate read access to time
remaining on the resource body timeout, and read access to the resource's properties. This allows a user associated lock token. The server
is free to
control the dissemination withhold any or all of their property data without overly
restricting this information if the requesting
principal does not have sufficient access rights to see the resource's contents.
16.6 Reduction of Security due to Source Link
requested data.
<!ELEMENT lockdiscovery (activelock)* >
13.8.1 Example - Retrieving the lockdiscovery Property
>>Request
PROPFIND /container/ HTTP/1.1 warns against providing read access to script code because
it may contain sensitive information. Yet WebDAV, via its source
link facility, can potentially provide a URL for script resources so
they may be authored. For HTTP/1.1,
Host: www.foo.bar
Content-Length: xxxx
Content-Type: text/xml; charset="utf-8"
<?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D='DAV:'>
<D:prop><D:lockdiscovery/></D:prop>
</D:propfind>
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>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D='DAV:'>
<D:response>
<D:href>http://www.foo.bar/container/</D:href>
<D:propstat>
<D:prop>
<D:lockdiscovery>
<D:activelock>
<D:locktype><D:write/></D:locktype>
<D:lockscope><D:exclusive/></D:lockscope>
<D:depth>0</D:depth>
<D:owner>Jane Smith</D:owner>
<D:timeout>Infinite</D:timeout>
<D:locktoken>
<D:href>
opaquelocktoken:f81de2ad-7f3d-a1b2-4f3c-00a0c91a9d76
</D:href>
</D:locktoken>
</D:activelock>
</D:lockdiscovery>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
This resource has a server could reasonably
prevent access to source resources due to single exclusive write lock on it, with an
infinite timeout.
13.9 resourcetype Property
Name: resourcetype
Namespace: DAV:
Purpose: Specifies the predominance nature of read-
only access. WebDAV, with its emphasis the resource.
Description: The resourcetype property MUST be defined on authoring, encourages
read and write access to all DAV
compliant resources. The default value is empty.
<!ELEMENT resourcetype ANY >
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13.10 source resources, and provides Property
Name: source
Namespace: DAV:
Purpose: The destination of the source link facility to identify identifies the source. This reduces
resource that contains the security
benefits of eliminating access to unprocessed source resources. Users and
administrators of WebDAV servers should be very cautious when
allowing remote authoring of scripts, limiting read and write access
to the link's source.
Description: The source resources to authorized principals.
17 IANA Considerations
This document defines two namespaces, of the namespace link (src) is typically the URI of property
names, and
the namespace output resource on which the link is defined, and there is
typically only one destination (dst) of WebDAV-specific XML elements used within
property values.
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URLs are used for both names, for several reasons. Assignment of a
URL does not require a request to a central naming authority, and
hence allow WebDAV property names and XML elements to be quickly
defined by any WebDAV user or application. URLs also provide a
unique address space, ensuring that the distributed users link, which is the URI
where the unprocessed source of WebDAV
will not have collisions among the property names and XML elements
they create.
This resource may be accessed. When
more than one link destination exists, this specification defines asserts no
policy on ordering.
<!ELEMENT source (link)* >
13.10.1 Example - A source Property
<?xml version="1.0" encoding="utf-8" ?>
<D:prop xmlns:D="DAV:" xmlns:F="http://www.foocorp.com/Project/">
<D:source>
<D:link>
<F:projfiles>Source</F:projfiles>
<D:src>http://foo.bar/program</D:src>
<D:dst>http://foo.bar/src/main.c</D:dst>
</D:link>
<D:link>
<F:projfiles>Library</F:projfiles>
<D:src>http://foo.bar/program</D:src>
<D:dst>http://foo.bar/src/main.lib</D:dst>
</D:link>
<D:link>
<F:projfiles>Makefile</F:projfiles>
<D:src>http://foo.bar/program</D:src>
<D:dst>http://foo.bar/src/makefile</D:dst>
</D:link>
</D:source>
</D:prop>
In this example the resource http://foo.bar/program has a distinguished set of source
property names and
XML elements that are understood by all WebDAV applications. The
property names contains three links. Each link contains three
elements, two of which, src and XML elements in this specification dst, are all
derived from the base URI DAV: by adding a suffix to this URI, for
example, DAV:creationdate for the "creationdate" property.
This specification also defines a URI scheme for the encoding part of
lock tokens, the opaquelocktoken URI scheme described DAV schema
defined in section
5.4.
To ensure correct interoperation based on this specification, IANA
must reserve the URI namespaces starting with "DAV:" document, and with
"opaquelocktoken:" for use one which is defined by this specification, its revisions, the schema
http://www.foocorp.com/project/ (Source, Library, and
related WebDAV specifications.
18 Terminology
Collection - Makefile). A resource that contains member resources and meets
client which only implements the
requirements elements in section 4 of this specification.
Member Resource - A resource contained by a collection.
Internal Member Resource - A member resource of a collection whose
URI is relative to the URI of DAV spec will not
understand the collection.
Property - A name/value pair that contains descriptive information foocorp elements and will ignore them, thus seeing
the expected source and destination links. An enhanced client may
know about a resource.
Live Property - A property whose semantics the foocorp elements and syntax are enforced
by be able to present the server. For example, a live "content-length" property would
have its value, user with
additional information about the length of links. This example demonstrates
the entity returned by power of XML markup, allowing element values to be enhanced
without breaking older clients.
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13.11 supportedlock Property
Name: supportedlock
Namespace: DAV:
Purpose: To provide a GET request,
automatically calculated by listing of the server.
Dead Property - A property whose semantics and syntax are not
enforced lock capabilities supported
by the server. resource.
Description: The server only records the value supportedlock property of a dead
property; the client is responsible for maintaining the consistency resource returns a
listing of the syntax and semantics combinations of a dead property.
Null Resource - A resource scope and access types which responds with may be
specified in a 404 Not Found lock request on the resource. Note that the actual
contents are themselves controlled by access controls so a server is
not required to
any HTTP/1.1 or DAV method except for PUT, MKCOL, OPTIONS and LOCK.
A NULL resource MUST NOT appear as a member of its parent
collection. provide information the client is not authorized to
see.
<!ELEMENT supportedlock (lockentry)* >
13.11.1 Example - Retrieving the supportedlock Property
>>Request
PROPFIND /container/ HTTP/1.1
Host: www.foo.bar
Content-Length: xxxx
Content-Type: text/xml; charset="utf-8"
<?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:">
<D:prop><D:supportedlock/></D:prop>
</D:propfind>
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19 Copyright
The following copyright notice is copied from RFC 2026 [Bradner,
1996], section 10.4, and describes the applicable copyright
>>Response
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"Content-Length: xxxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>http://www.foo.bar/container/</D:href>
<D:propstat>
<D:prop>
<D:supportedlock>
<D:lockentry>
<D:lockscope><D:exclusive/></D:lockscope>
<D:locktype><D:write/></D:locktype>
</D:lockentry>
<D:lockentry>
<D:lockscope><D:shared/></D:lockscope>
<D:locktype><D:write/></D:locktype>
</D:lockentry>
</D:supportedlock>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
14 Instructions for this
document.
Copyright (C) The Internet Society April 5, 1998. Processing XML in DAV
All Rights
Reserved.
This document and translations of it may be copied and furnished to
others, DAV compliant resources MUST ignore any unknown XML element and derivative works
all its children encountered while processing a DAV method that comment on or otherwise explain it
or assist in uses
XML as its implementation may be prepared, copied, published
and distributed, in whole or in part, without command language.
This restriction of any
kind, provided that also applies to the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as processing, by removing clients, of DAV
property values where unknown XML elements SHOULD be ignored unless
the copyright notice or references property's schema declares otherwise.
This restriction does not apply to setting dead DAV properties on
the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case server where the procedures for
copyrights defined in server MUST record unknown XML elements.
Additionally, this restriction does not apply to the Internet Standards process must be
followed, or as required use of XML
where XML happens to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assignees.
This document and content type of the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR entity body, for
example, when used as the body of a PUT.
Goland et al. [Page 72]
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15 DAV Compliance Classes
A PARTICULAR PURPOSE.
20 Intellectual Property
The following notice is copied DAV compliant resource can choose from RFC 2026 [Bradner, 1996],
section 10.4, and describes the position two classes of compliance.
A client can discover the IETF concerning
intellectual property claims made against this document.
The IETF takes no position regarding the validity or scope compliance classes of any
intellectual property or other rights that might be claimed to
pertain to a resource by
executing OPTIONS on the implementation or use other technology described in resource, and examining the "DAV" header
which is returned.
Since this document or the extent describes extensions to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track HTTP/1.1 protocol,
minimally all DAV compliant resources, clients, and
standards-related documentation can proxies MUST be found in BCP-11. Copies of
claims of rights made available for publication and any assurances
of licenses to
compliant with [RFC2068].
Compliance classes are not necessarily sequential. A resource that
is class 2 compliant must also be made available, or the result of an attempt made
to obtain class 1 compliant; but if
additional compliance classes are defined later, a general license or permission for the use of such
proprietary rights by implementors or users of this specification
can resource that is
class 1, 2, and 4 compliant might not be obtained from the IETF Secretariat.
Goland et al. [Page 73]
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The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology class 3 compliant. Also
note that identifiers other than numbers may be required to practice used as compliance
class identifiers.
15.1 Class 1
A class 1 compliant resource MUST meet all "MUST" requirements in
all sections of this standard. Please address document.
Class 1 compliant resources MUST return, at minimum, the information value "1"
in the DAV header on all responses to the IETF Executive
Director.
21 Acknowledgements OPTIONS method.
15.2 Class 2
A specification such as this thrives on piercing critical review class 2 compliant resource MUST meet all class 1 requirements and
withers from apathetic neglect. The authors gratefully acknowledge
support the contributions of LOCK method, the following people, whose insights were so
valuable at every stage of our work.
Terry Allen, Harald Alvestrand, Jim Amsden, Becky Anderson, Alan
Babich, Sanford Barr, Dylan Barrell, Bernard Chester, Tim Berners-
Lee, Dan Connolly, Jim Cunningham, Ron Daniel, Jr., Jim Davis, Keith
Dawson, Mark Day, Brian Deen, Martin Duerst, David Durand, Lee
Farrell, Chuck Fay, Wesley Felter, Roy Fielding, Mark Fisher, Alan
Freier, George Florentine, Jim Gettys, Phill Hallam-Baker, Dennis
Hamilton, Steve Henning, Mead Himelstein, Alex Hopmann, Andre van
der Hoek, Ben Laurie, Paul Leach, Ora Lassila, Karen MacArthur,
Steven Martin, Larry Masinter, Michael Mealling, Keith Moore, Henrik
Nielsen, Kenji Ota, Bob Parker, Glenn Peterson, Jon Radoff, Saveen
Reddy, Henry Sanders, Christopher Seiwald, Judith Slein, Mike
Spreitzer, Einar Stefferud, Ralph Swick, Kenji Takahashi, Richard N.
Taylor, Robert Thau, John Turner, Sankar Virdhagriswaran, Fabio
Vitali, Gregory Woodhouse, supportedlock property, the
lockdiscovery property, the Time-Out response header and Lauren Wood.
Two from this list deserve special mention. The contributions by
Larry Masinter have been invaluable, both in helping the formation
of Lock-
Token request header. A class "2" compliant resource SHOULD also
support the working group Time-Out request header and the owner XML element.
Class 2 compliant resources MUST return, at minimum, the values "1"
and "2" in patiently coaching the authors along DAV header on all responses to the
way. OPTIONS method.
16 Internationalization Considerations
In so many ways he has set high standards we have toiled to
meet. The contributions the realm of Judith Slein in clarifying internationalization, this specification complies
with the
requirements, and IETF Character Set Policy [RFC2277]. In this specification,
human-readable fields can be found either in patiently reviewing draft after draft, the value of a
property, or in an error message returned in a response entity body.
In both
improved cases, the human-readable content is encoded using XML,
which has explicit provisions for character set tagging and
encoding, and requires that XML processors read XML elements
encoded, at minimum, using the UTF-8 [UTF-8] encoding of the ISO
10646 multilingual plane. XML examples in this specification and expanded our minds on document
management.
We would also like to thank John Turner for developing
demonstrate use of the charset parameter of the Content-Type header,
as defined in [RFC2376], as well as the XML DTD. "encoding" attribute,
Goland et al. [Page 74] 73]
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22 References
22.1 Normative References
[Alvestrand, 1995] H. T. Alvestrand, "Tags
which together provide charset identification information for the Identification of
Languages." RFC 1766. Uninett. March, 1995.
[Alvestrand, 1998] H. T. Alvestrand, "IETF Policy on Character Sets MIME
and Languages." RFC 2277, BCP 18. Uninett. January, 1998.
[Bradner, 1997] S. Bradner, "Key words XML processors.
XML also provides a language tagging capability for use specifying the
language of the contents of a particular XML element. XML uses
either IANA registered language tags (see [RFC1766]) or ISO 639
language tags [ISO-639] in RFCs the "xml:lang" attribute of an XML
element to Indicate
Requirement Levels." RFC 2119, BCP 14. Harvard University. March,
1997.
[Bray, Paoli, Sperberg-McQueen, 1998] T. Bray, J. Paoli, C. M.
Sperberg-McQueen, "Extensible Markup Language (XML)." World Wide Web
Consortium Recommendation REC-xml-19980210.
http://www.w3.org/TR/1998/REC-xml-19980210.
[Franks et al., 1997] J. Franks, P. Hallam-Baker, J. Hostetler, P.
Leach, A. Luotonen, E. Sink, identify the language of its content and L. Stewart. "An Extension to HTTP :
Digest Access Authentication" RFC 2069. Northwestern University,
CERN, Spyglass Inc., Microsoft Corp., Netscape Communications Corp.,
Spyglass Inc., Open Market Inc. January 1997.
[Fielding et al., 1997] R. Fielding, J. Gettys, J. Mogul, H.
Frystyk, T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1."
RFC 2068. U.C. Irvine, DEC, MIT/LCS. January, 1997.
[ISO-639] ISO (International Organization attributes.
WebDAV applications MUST support the character set tagging,
character set encoding, and the language tagging functionality of
the XML specification. Implementors of WebDAV applications are
strongly encouraged to read "XML Media Types" [RFC2376] for Standardization). ISO
639:1988. "Code
instruction on which MIME media type to use for XML transport, and
on use of the representation charset parameter of the Content-Type header.
Names used within this specification fall into three categories:
names of languages."
[ISO-8601] ISO (International Organization for Standardization). ISO
8601:1988. "Data protocol elements such as methods and interchange formats - Information
interchange - Representation headers, names of dates and times."
[Leach, Salz, 1998] P. J. Leach, R. Salz, "UUIDs XML
elements, and GUIDs."
Internet-draft, work-in-progress, February, 1998.
ftp://ietf.org/internet-drafts/draft-leach-uuids-guids-01.txt
[Yergeau, 1998] F. Yergeau, "UTF-8, a transformation format names of
Unicode and ISO 10646." RFC 2279. Alis Technologies. January, 1998.
22.2 Informational References
[Bradner, 1996] S. Bradner, "The Internet Standards Process -
Revision 3." RFC 2026, BCP 9. Harvard University. October, 1996.
[Bray, Hollander, Layman, 1998] T. Bray, D. Hollander, A. Layman,
"Name Spaces properties. Naming of protocol elements
follows the precedent of HTTP, using English names encoded in XML" World Wide Web Consortium Working Draft,
http://www.w3.org/TR/WD-xml-names.
Goland et al. [Page 75]
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[Lasher, Cohen, 1995] R. Lasher, D. Cohen, "A Format
USASCII for
Bibliographic Records," RFC 1807. Stanford, Myricom. June, 1995.
[MARC, 1994] Network Development methods and MARC Standards, Office, ed.
1994. "USMARC Format for Bibliographic Data", 1994. Washington, DC:
Cataloging Distribution Service, Library of Congress.
[Miller et al., 1996] J. Miller, T. Krauskopf, P. Resnick, W.
Treese, "PICS Label Distribution Label Syntax and Communication
Protocols" Version 1.1, World Wide Web Consortium Recommendation
REC-PICS-labels-961031. http://www.w3.org/pub/WWW/TR/REC-PICS-
labels-961031.html.
[Slein et al., 1998] J. A. Slein, F. Vitali, E. J. Whitehead, Jr.,
D. Durand, "Requirements for Distributed Authoring and Versioning
Protocol for the World Wide Web." RFC 2291. Xerox, Univ. of Bologna,
U.C. Irvine, Boston Univ. February, 1998.
[Weibel et al., 1995] S. Weibel, J. Godby, E. Miller, R. Daniel,
"OCLC/NCSA Metadata Workshop Report."
http://purl.oclc.org/metadata/dublin_core_report.
Goland et al. [Page 76]
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23 Authors' Addresses
Y. Y. Goland
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052-6399
Email: yarong@microsoft.com
E. J. Whitehead, Jr.
Dept. Of Information headers. Since these protocol elements are
not visible to users, and Computer Science
University of California, Irvine
Irvine, CA 92697-3425
Email: ejw@ics.uci.edu
A. Faizi
Netscape
685 East Middlefield Road
Mountain View, CA 94043
Email: asad@netscape.com
S. R. Carter
Novell
1555 N. Technology Way
M/S ORM F111
Orem, UT 84097-2399
Email: srcarter@novell.com
D. Jensen
Novell
1555 N. Technology Way
M/S ORM F111
Orem, UT 84097-2399
Email: dcjensen@novell.com
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24 Appendices
24.1 Appendix 1 - WebDAV Document Type Definition
This section provides a document type definition, following the
rules are in [Bray, Paoli, Sperberg-McQueen, 1998], for fact simply long token identifiers,
they do not need to support encoding in multiple character sets.
Similarly, though the names of XML elements used in the protocol stream and this
specification are English names encoded in UTF-8, these names are
not visible to the values of properties. It
collects the element definitions given in user, and hence do not need to support multiple
character set encodings.
The name of a property defined on a resource is a URI. Although
some applications (e.g., a generic property viewer) will display
property URIs directly to their users, it is expected that the
typical application will use a fixed set of properties, and will
provide a mapping from the property name URI to a human-readable
field when displaying the property name to a user. It is only in
the case where the set of properties is not known ahead of time that
an application need display a property name URI to a user. We
recommend that applications provide human-readable property names
wherever feasible.
For error reporting, we follow the convention of HTTP/1.1 status
codes, including with each status code a short, English description
of the code (e.g., 423 (Locked)). While the possibility exists that
a poorly crafted user agent would display this message to a user,
internationalized applications will ignore this message, and display
an appropriate message in the user's language and character set.
Since interoperation of clients and servers does not require locale
information, this specification does not specify any mechanism for
transmission of this information.
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17 Security Considerations
This section is provided to detail issues concerning security
implications of which WebDAV applications need to be aware.
All of the security considerations of HTTP/1.1 (discussed in
[RFC2068]) and XML (discussed in [RFC2376]) also apply to WebDAV. In
addition, the security risks inherent in remote authoring require
stronger authentication technology, introduce several new privacy
concerns, and may increase the hazards from poor server design.
These issues are detailed below.
17.1 Authentication of Clients
Due to their emphasis on authoring, WebDAV servers need to use
authentication technology to protect not just access to a network
resource, but the integrity of the resource as well. Furthermore,
the introduction of locking functionality requires support for
authentication.
A password sent in the clear over an insecure channel is an
inadequate means for protecting the accessibility and integrity of a
resource as the password may be intercepted. Since Basic
authentication for HTTP/1.1 performs essentially clear text
transmission of a password, Basic authentication MUST NOT be used to
authenticate a WebDAV client to a server unless the connection is
secure. Furthermore, a WebDAV server MUST NOT send Basic
authentication credentials in a WWW-Authenticate header unless the
connection is secure. Examples of secure connections include a
Transport Layer Security (TLS) connection employing a strong cipher
suite with mutual authentication of client and server, or a
connection over a network which is physically secure, for example,
an isolated network in a building with restricted access.
WebDAV applications MUST support the Digest authentication scheme
[RFC2069]. Since Digest authentication verifies that both parties to
a communication know a shared secret, a password, without having to
send that secret in the clear, Digest authentication avoids the
security problems inherent in Basic authentication while providing a
level of authentication which is useful in a wide range of
scenarios.
17.2 Denial of Service
Denial of service attacks are of special concern to WebDAV servers.
WebDAV plus HTTP enables denial of service attacks on every part of
a system's resources.
The underlying storage can be attacked by PUTting extremely large
files.
Goland et al. [Page 75]
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Asking for recursive operations on large collections can attack
processing time.
Making multiple pipelined requests on multiple connections can
attack network connections.
WebDAV servers need to be aware of the possibility of a denial of
service attack at all levels.
17.3 Security through Obscurity
WebDAV provides, through the PROPFIND method, a mechanism for
listing the member resources of a collection. This greatly
diminishes the effectiveness of security or privacy techniques that
rely only on the difficulty of discovering the names of network
resources. Users of WebDAV servers are encouraged to use access
control techniques to prevent unwanted access to resources, rather
than depending on the relative obscurity of their resource names.
17.4 Privacy Issues Connected to Locks
When submitting a lock request a user agent may also submit an owner
XML field giving contact information for the person taking out the
lock (for those cases where a person, rather than a robot, is taking
out the lock). This contact information is stored in a lockdiscovery
property on the resource, and can be used by other collaborators to
begin negotiation over access to the resource. However, in many
cases this contact information can be very private, and should not
be widely disseminated. Servers SHOULD limit read access to the
lockdiscovery property as appropriate. Furthermore, user agents
SHOULD provide control over whether contact information is sent at
all, and if contact information is sent, control over exactly what
information is sent.
17.5 Privacy Issues Connected to Properties
Since property values are typically used to hold information such as
the author of a document, there is the possibility that privacy
concerns could arise stemming from widespread access to a resource's
property data. To reduce the risk of inadvertent release of private
information via properties, servers are encouraged to develop access
control mechanisms that separate read access to the resource body
and read access to the resource's properties. This allows a user to
control the dissemination of their property data without overly
restricting access to the resource's contents.
17.6 Reduction of Security due to Source Link
HTTP/1.1 warns against providing read access to script code because
it may contain sensitive information. Yet WebDAV, via its source
link facility, can potentially provide a URL for script resources so
they may be authored. For HTTP/1.1, a server could reasonably
Goland et al. [Page 76]
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prevent access to source resources due to the predominance of read-
only access. WebDAV, with its emphasis on authoring, encourages
read and write access to source resources, and provides the source
link facility to identify the source. This reduces the security
benefits of eliminating access to source resources. Users and
administrators of WebDAV servers should be very cautious when
allowing remote authoring of scripts, limiting read and write access
to the source resources to authorized principals.
17.7 Implications of XML External Entities
XML supports a facility known as "external entities", defined in
section 4.2.2 of [REC-XML], which instruct an XML processor to
retrieve and perform an inline include of XML located at a
particular URI. An external XML entity can be used to append or
modify the document type declaration (DTD) associated with an XML
document. An external XML entity can also be used to include XML
within the content of an XML document. For non-validating XML, such
as the XML used in this specification, including an external XML
entity is not required by [REC-XML]. However, [REC-XML] does state
that an XML processor may, at its discretion, include the external
XML entity.
External XML entities have no inherent trustworthiness and are
subject to all the attacks that are endemic to any HTTP GET request.
Furthermore, it is possible for an external XML entity to modify the
DTD, and hence affect the final form of an XML document, in the
worst case significantly modifying its semantics, or exposing the
XML processor to the security risks discussed in [RFC2376].
Therefore, implementers must be aware that external XML entities
should be treated as untrustworthy.
There is also the scalability risk that would accompany a widely
deployed application which made use of external XML entities. In
this situation, it is possible that there would be significant
numbers of requests for one external XML entity, potentially
overloading any server which fields requests for the resource
containing the external XML entity.
17.8 Risks Connected with Lock Tokens
This specification, in section 6.4, requires the use of Globally
Unique Identifiers (GUIDs) for lock tokens, in order to guarantee
their uniqueness across space and time. GUIDs, as defined in [ISO-
11578], contain a "node" field which "consists of the IEEE address,
usually the host address. For systems with multiple IEEE 802 nodes,
any available node address can be used." Since a WebDAV server will
issue many locks over its lifetime, the implication is that it will
also be publicly exposing its IEEE 802 address.
There are several risks associated with exposure of IEEE 802
addresses. Using the IEEE 802 address:
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* It is possible to track the movement of hardware from subnet to
subnet.
* It may be possible to identify the manufacturer of the hardware
running a WebDAV server.
* It may be possible to determine the number of each type of
computer running WebDAV.
Section 6.4.1 of this specification details an alternate mechanism
for generating the "node" field of a GUID without using an IEEE 802
address, which alleviates the risks associated with exposure of IEEE
802 addresses by using an alternate source of uniqueness.
18 IANA Considerations
This document defines two namespaces, the namespace of property
names, and the namespace of WebDAV-specific XML elements used within
property values.
URLs are used for both names, for several reasons. Assignment of a
URL does not require a request to a central naming authority, and
hence allow WebDAV property names and XML elements to be quickly
defined by any WebDAV user or application. URLs also provide a
unique address space, ensuring that the distributed users of WebDAV
will not have collisions among the property names and XML elements
they create.
This specification defines a distinguished set of property names and
XML elements that are understood by all WebDAV applications. The
property names and XML elements in this specification are all
derived from the base URI DAV: by adding a suffix to this URI, for
example, DAV:creationdate for the "creationdate" property.
This specification also defines a URI scheme for the encoding of
lock tokens, the opaquelocktoken URI scheme described in section
6.4.
To ensure correct interoperation based on this specification, IANA
must reserve the URI namespaces starting with "DAV:" and with
"opaquelocktoken:" for use by this specification, its revisions, and
related WebDAV specifications.
19 Copyright
The following copyright notice is copied from RFC 2026 [RFC2026],
section 10.4, and describes the applicable copyright for this
document.
Copyright (C) The Internet Society 1998. All Rights Reserved.
Goland et al. [Page 78]
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This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assignees.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
20 Intellectual Property
The following notice is copied from RFC 2026 [RFC2026], section
10.4, and describes the position of the IETF concerning intellectual
property claims made against this document.
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use other technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances
of licenses to be made available, or the result of an attempt made
to obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification
can be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
Goland et al. [Page 79]
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21 Acknowledgements
A specification such as this thrives on piercing critical review and
withers from apathetic neglect. The authors gratefully acknowledge
the contributions of the following people, whose insights were so
valuable at every stage of our work.
Terry Allen, Harald Alvestrand, Jim Amsden, Becky Anderson, Alan
Babich, Sanford Barr, Dylan Barrell, Bernard Chester, Tim Berners-
Lee, Dan Connolly, Jim Cunningham, Ron Daniel, Jr., Jim Davis, Keith
Dawson, Mark Day, Brian Deen, Martin Duerst, David Durand, Lee
Farrell, Chuck Fay, Wesley Felter, Roy Fielding, Mark Fisher, Alan
Freier, George Florentine, Jim Gettys, Phill Hallam-Baker, Dennis
Hamilton, Steve Henning, Mead Himelstein, Alex Hopmann, Andre van
der Hoek, Ben Laurie, Paul Leach, Ora Lassila, Karen MacArthur,
Steven Martin, Larry Masinter, Michael Mealling, Keith Moore, Henrik
Nielsen, Kenji Ota, Bob Parker, Glenn Peterson, Jon Radoff, Saveen
Reddy, Henry Sanders, Christopher Seiwald, Judith Slein, Mike
Spreitzer, Einar Stefferud, Greg Stein, Ralph Swick, Kenji
Takahashi, Richard N. Taylor, Robert Thau, John Turner, Sankar
Virdhagriswaran, Fabio Vitali, Gregory Woodhouse, and Lauren Wood.
Two from this list deserve special mention. The contributions by
Larry Masinter have been invaluable, both in helping the formation
of the working group and in patiently coaching the authors along the
way. In so many ways he has set high standards we have toiled to
meet. The contributions of Judith Slein in clarifying the
requirements, and in patiently reviewing draft after draft, both
improved this specification and expanded our minds on document
management.
We would also like to thank John Turner for developing the XML DTD.
Goland et al. [Page 80]
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22 References
22.1 Normative References
[RFC1766] H. T. Alvestrand, "Tags for the Identification of
Languages." RFC 1766. Uninett. March, 1995.
[RFC2277] H. T. Alvestrand, "IETF Policy on Character Sets and
Languages." RFC 2277, BCP 18. Uninett. January, 1998.
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels." RFC 2119, BCP 14. Harvard
University. March, 1997.
[RFC2396] T. Berners-Lee, R. Fielding, L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax." RFC 2396.
MIT/LCS, U.C. Irvine, Xerox. August, 1998.
[REC-XML] T. Bray, J. Paoli, C. M. Sperberg-McQueen, "Extensible
Markup Language (XML)." World Wide Web Consortium
Recommendation REC-xml-19980210.
http://www.w3.org/TR/1998/REC-xml-19980210.
[RFC2069] J. Franks, P. Hallam-Baker, J. Hostetler, P. Leach, A.
Luotonen, E. Sink, and L. Stewart. "An Extension to HTTP :
Digest Access Authentication" RFC 2069. Northwestern
University, CERN, Spyglass Inc., Microsoft Corp., Netscape
Communications Corp., Spyglass Inc., Open Market Inc.
January 1997.
[RFC2068] R. Fielding, J. Gettys, J. Mogul, H. Frystyk, T. Berners-
Lee, "Hypertext Transfer Protocol -- HTTP/1.1." RFC 2068.
U.C. Irvine, DEC, MIT/LCS. January, 1997.
[ISO-639] ISO (International Organization for Standardization). ISO
639:1988. "Code for the representation of names of
languages."
[ISO-8601] ISO (International Organization for Standardization). ISO
8601:1988. "Data elements and interchange formats -
Information interchange - Representation of dates and
times."
[ISO-11578] ISO (International Organization for Standardization).
ISO/IEC 11578:1996. "Information technology - Open Systems
Interconnection - Remote Procedure Call (RPC)"
[UTF-8] F. Yergeau, "UTF-8, a transformation format of Unicode and
ISO 10646." RFC 2279. Alis Technologies. January, 1998.
Goland et al. [Page 81]
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22.2 Informational References
[RFC2026] S. Bradner, "The Internet Standards Process - Revision 3."
RFC 2026, BCP 9. Harvard University. October, 1996.
[WD-XML-NAMES] T. Bray, D. Hollander, A. Layman, "Name Spaces in
XML" World Wide Web Consortium Working Draft,
http://www.w3.org/TR/WD-xml-names.
[RFC1807] R. Lasher, D. Cohen, "A Format for Bibliographic Records,"
RFC 1807. Stanford, Myricom. June, 1995.
[USMARC] Network Development and MARC Standards, Office, ed. 1994.
"USMARC Format for Bibliographic Data", 1994. Washington,
DC: Cataloging Distribution Service, Library of Congress.
[REC-PICS] J. Miller, T. Krauskopf, P. Resnick, W. Treese, "PICS
Label Distribution Label Syntax and Communication
Protocols" Version 1.1, World Wide Web Consortium
Recommendation REC-PICS-labels-961031.
http://www.w3.org/pub/WWW/TR/REC-PICS-labels-961031.html.
[RFC2291] J. A. Slein, F. Vitali, E. J. Whitehead, Jr., D. Durand,
"Requirements for Distributed Authoring and Versioning
Protocol for the World Wide Web." RFC 2291. Xerox, Univ.
of Bologna, U.C. Irvine, Boston Univ. February, 1998.
[RFC2413] S. Weibel, J. Kunze, C. Lagoze, M. Wolf, "Dublin Core
Metadata for Resource Discovery." RFC 2413. OCLC, UCSF,
Cornell, Reuters. September, 1998.
[RFC2376] E. Whitehead, M. Murata, "XML Media Types." RFC 2376. U.C.
Irvine, Fuji Xerox Info. Systems. July 1998.
Goland et al. [Page 82]
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23 Authors' Addresses
Y. Y. Goland
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052-6399
Email: yarong@microsoft.com
E. J. Whitehead, Jr.
Dept. Of Information and Computer Science
University of California, Irvine
Irvine, CA 92697-3425
Email: ejw@ics.uci.edu
A. Faizi
Netscape
685 East Middlefield Road
Mountain View, CA 94043
Email: asad@netscape.com
S. R. Carter
Novell
1555 N. Technology Way
M/S ORM F111
Orem, UT 84097-2399
Email: srcarter@novell.com
D. Jensen
Novell
1555 N. Technology Way
M/S ORM F111
Orem, UT 84097-2399
Email: dcjensen@novell.com
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24 Appendices
24.1 Appendix 1 - WebDAV Document Type Definition
This section provides a document type definition, following the
rules in [REC-XML], for the XML elements used in the protocol stream
and in the values of properties. It collects the element definitions
given in sections 11 12 and 12. 13.
<!DOCTYPE webdav-1.0 [
<!--============ XML Elements from Section 11 12 ==================-->
<!ELEMENT activelock (lockscope, locktype, depth, owner?, timeout?,
locktoken?) >
<!ELEMENT lockentry (lockscope, locktype) >
<!ELEMENT lockinfo (lockscope, locktype, owner?) >
<!ELEMENT locktype (write) >
<!ELEMENT write EMPTY >
<!ELEMENT lockscope (exclusive | shared) >
<!ELEMENT exclusive EMPTY >
<!ELEMENT shared EMPTY >
<!ELEMENT depth (#PCDATA) >
<!ELEMENT owner ANY >
<!ELEMENT timeout (#PCDATA) >
<!ELEMENT locktoken (href+) >
<!ELEMENT href (#PCDATA) >
<!ELEMENT link (src+, dst+) >
<!ELEMENT dst (#PCDATA) >
<!ELEMENT src (#PCDATA) >
<!ELEMENT multistatus (response+, responsedescription?) >
<!ELEMENT response (href, ((href*, status)|(propstat+)),
responsedescription?) >
<!ELEMENT status (#PCDATA) >
<!ELEMENT propstat (prop, status) status, responsedescription?) >
<!ELEMENT responsedescription (#PCDATA) >
<!ELEMENT prop ANY >
<!ELEMENT propertybehavior (omit | keepalive) >
<!ELEMENT omit EMPTY >
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<!ELEMENT keepalive (#PCDATA | href+) >
<!ELEMENT propertyupdate (remove | set)+ >
<!ELEMENT remove (prop) >
<!ELEMENT set (prop) >
<!ELEMENT propfind (allprop | propname | prop) >
<!ELEMENT allprop EMPTY >
<!ELEMENT propname EMPTY >
<!ELEMENT collection EMPTY >
<!--=========== Property Elements from Section 12 ===============-->
<!ELEMENT creationdate (#PCDATA) >
<!ELEMENT displayname (#PCDATA) >
<!ELEMENT getcontentlanguage (#PCDATA) >
<!ELEMENT getcontentlength (#PCDATA) >
<!ELEMENT getcontenttype (#PCDATA) >
<!ELEMENT getetag (#PCDATA) >
<!ELEMENT getlastmodified (#PCDATA) >
<!ELEMENT lockdiscovery (activelock)* >
<!ELEMENT resourcetype ANY >
<!ELEMENT source (link)* >
<!ELEMENT supportedlock (lockentry)* >
]>
24.2 Section 13 ===============-->
<!ELEMENT creationdate (#PCDATA) >
<!ELEMENT displayname (#PCDATA) >
<!ELEMENT getcontentlanguage (#PCDATA) >
<!ELEMENT getcontentlength (#PCDATA) >
<!ELEMENT getcontenttype (#PCDATA) >
<!ELEMENT getetag (#PCDATA) >
<!ELEMENT getlastmodified (#PCDATA) >
<!ELEMENT lockdiscovery (activelock)* >
<!ELEMENT resourcetype ANY >
<!ELEMENT source (link)* >
<!ELEMENT supportedlock (lockentry)* >
]>
24.2 Appendix 2 - ISO 8601 Date and Time Profile
The creationdate property specifies the use of the ISO 8601 date
format [ISO-8601]. This section defines a profile of the ISO 8601
date format for use with this specification. This profile is quoted
verbatim from draft-newman-datetime-01.txt (expired).
date-time = full-date "T" full-time
full-date = date-fullyear "-" date-month "-" date-mday
full-time = partial-time time-offset
date-fullyear = 4DIGIT
date-month = 2DIGIT ; 01-12
date-mday = 2DIGIT ; 01-28, 01-29, 01-30, 01-31 based on
month/year
time-hour = 2DIGIT ; 00-23
time-minute = 2DIGIT ; 00-59
time-second = 2DIGIT ; 00-59, 00-60 based on leap second rules
time-secfrac = "." 1*DIGIT
time-numoffset = ("+" / "-") time-hour ":" time-minute
time-offset = "Z" / time-numoffset
partial-time = time-hour ":" time-minute ":" time-second
[time-secfrac]
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Numeric offsets are calculated as local time minus UTC (Coordinated
Universal Time). So the equivalent time in UTC can be determined by
subtracting the offset from the local time. For example, 18:50:00-
04:00 is the same time as 22:58:00Z.
If the time in UTC is known, but the offset to local time is
unknown, this can be represented with an offset of "-00:00". This
differs from an offset of "Z" which implies that UTC is the
preferred reference point for the specified time.
24.3 Appendix 2 3 - ISO 8601 Date and Time Profile Notes on Processing XML Elements
24.3.1 Notes on Empty XML Elements
XML supports two mechanisms for indicating that an XML element does
not have any content. The first is to declare an XML element of the
form <A></A>. The second is to declare an XML element of the form
<A/>. The two XML elements are semantically identical.
It is a violation of the XML specification to use the <A></A> form
if the associated DTD declares the element to be EMPTY (e.g.,
<!ELEMENT A EMPTY>). If such a statement is included, then the
empty element format, <A/> must be used. If the element is not
delcared to be EMPTY, then either form <A></A> or <A/> may be used
for empty elements.
24.3.2 Notes on Illegal XML Processing
XML is a flexible data format that makes it easy to submit data that
appears legal but in fact is not. The creationdate property specifies the use philosophy of the ISO 8601 date
format [ISO-8601]. "Be flexible in
what you accept and strict in what you send" still applies, but it
must not be applied inappropriately. XML is extremely flexible in
dealing with issues of white space, element ordering, inserting new
elements, etc. This section defines a profile flexibility does not require extension,
especially not in the area of the ISO 8601
date format meaning of elements.
There is no kindness in accepting illegal combinations of XML
elements. At best it will cause an unwanted result and at worst it
can cause real damage.
24.3.2.1 Example - XML Syntax Error
The following request body for use with this specification. This profile a PROPFIND method is quoted
verbatim from draft-newman-datetime-01.txt (expired).
date-time = full-date "T" full-time
full-date = date-fullyear "-" date-month "-" date-mday
full-time = partial-time time-offset
date-fullyear = 4DIGIT
date-month = 2DIGIT ; 01-12
date-mday = 2DIGIT ; 01-28, 01-29, 01-30, 01-31 based on
month/year
time-hour = 2DIGIT ; 00-23
time-minute = 2DIGIT ; 00-59
time-second = 2DIGIT ; 00-59, 00-60 based on leap second rules
time-secfrac = "." 1*DIGIT
time-numoffset = ("+" / "-") time-hour ":" time-minute
time-offset = "Z" / time-numoffset
partial-time = time-hour ":" time-minute ":" time-second
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[time-secfrac]
Numeric offsets are calculated as local time minus UTC (Coordinated
Universal Time). So illegal.
<?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:">
<D:allprop/>
<D:propname/>
</D:propfind>
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The definition of the equivalent time in UTC can be determined by
subtracting propfind element only allows for the offset from allprop
or the local time. For example, 18:50:00-
04:00 propname element, not both. Thus the above is an error and
must be responded to with a 400 (Bad Request).
Imagine, however, that a server wanted to be "kind" and decided to
pick the same time allprop element as 22:58:00Z.
If the time true element and respond to it. A
client running over a bandwidth limited line who intended to execute
a propname would be in UTC is known, but for a big surprise if the offset server treated the
command as an allprop.
Additionally, if a server were lenient and decided to reply to local time is
unknown, this can be represented with an offset of "-00:00". This
differs
request, the results would vary randomly from an offset of "Z" which implies that UTC is server to server, with
some servers executing the
preferred reference point for allprop directive, and others executing
the specified time.
24.3 Appendix 3 propname directive. This reduces interoperability rather than
increasing it.
24.3.2.2 Example - Notes on Processing XML Elements
24.3.1 Notes on Empty XML Elements Unknown XML supports Element
The previous example was illegal because it contained two mechanisms elements
that were explicitly banned from appearing together in the propfind
element. However, XML is an extensible language, so one can imagine
new elements being defined for indicating use with propfind. Below is the
request body of a PROPFIND and, like the previous example, must be
rejected with a 400 (Bad Request) by a server that an XML element does not have any content. The first
understand the expired-props element.
<?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:"
xmlns:E="http://www.foo.bar/standards/props/">
<E:expired-props/>
</D:propfind>
To understand why a 400 (Bad Request) is returned let us look at the
request body as the server unfamiliar with expired-props sees it.
<?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:"
xmlns:E="http://www.foo.bar/standards/props/">
</D:propfind>
As the server does not understand the expired-props element,
according to declare an the WebDAV-specific XML element of processing rules specified in
section 14, it must ignore it. Thus the
form <A></A>. The second is to declare server sees an XML element empty
propfind, which by the definition of the form
<A/>. The two XML elements are semantically identical.
It propfind element is
illegal.
Please note that had the extension been additive it would not
necessarily have resulted in a violation of 400 (Bad Request). For example,
imagine the XML specification following request body for a PROPFIND:
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<?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:"
xmlns:E="http://www.foo.bar/standards/props/">
<D:propname/>
<E:leave-out>*boss*</E:leave-out>
</D:propfind>
The previous example contains the fictitious element leave-out. Its
purpose is to use prevent the <A></A> form
if return of any property whose name matches
the associated DTD declares submitted pattern. If the element previous example were submitted to be EMPTY (e.g.,
<!ELEMENT A EMPTY>). If such a statement is included, then
server unfamiliar with leave-out, the
empty element format, <A/> must only result would be used. If that the
leave-out element is not
delcared to would be EMPTY, then either form <A></A> or <A/> may ignored and a propname would be used executed.
24.4 Appendix 4 -- XML Namespaces for empty elements.
24.3.2 Notes on Illegal WebDAV
24.4.1 Introduction
To provide a unique space of XML element names which has
decentralized extensibility, this specification uses a feature of
XML Processing known as XML is "namespaces". This appendix provides a flexible data format that makes it easy to submit data that
appears legal but normative
reference for XML namespace functionality for implementations of
this specification. All DAV compliant systems MUST support the XML
namespace extension as specified in fact is not. this appendix.
The philosophy remainder of "Be flexible this appendix is intended to match, as closely as
needed, the text in
what you accept WD-xml-names-19980916, "Namespaces in XML",
edited by Tim Bray, Dave Hollander, and strict Andrew Layman [WD-XML-
NAMES]. To meet this goal, the text in what you send" still applies, but it
must not be applied inappropriately. XML this appendix is extremely flexible in
dealing with issues mostly
quoted verbatim from sections 1-6 of white space, element ordering, inserting new
elements, etc. This flexibility does not require extension,
especially not in that source. However, some
minor changes were made, specifically to make the area of references match
the meaning style of elements.
There is this document, and a forward reference to appendix A
(non-normative) of [REC-XML] was removed, as no kindness in accepting illegal combinations appendices of [REC-
XML] are duplicated here.
24.4.2 Motivation and Summary
We envision applications of Extensible Markup Language (XML) where a
single XML
elements. At best it will cause an unwanted result document may contain elements and at worst attributes that are
defined for and used by multiple software modules. One motivation
for this is modularity; if such a markup vocabulary exists which is
well-understood and for which there is useful software available, it
can cause real damage.
24.3.2.1 Example - XML Syntax Error
The following request body
is better to re-use this markup rather than re-invent it.
Such documents, containing multiple markup vocabularies, pose
problems of recognition and collision. Software modules need to be
able to recognize the tags and attributes which they are designed to
process, even in the face of "collisions" occurring when markup
intended for a PROPFIND method is illegal.
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<D:propfind>
<D:allprop/>
<D:propname/>
</D:propfind> some other software package uses the same element type
or attribute name.
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The definition of the propfind element only allows for the allprop
or the propname element, not both. Thus the above
These considerations require that document constructs should have
universal names, whose scope extends beyond their containing
document. This specification describes a mechanism, XML namespaces,
which accomplishes this.
[Definition:] An XML namespace is an error and
must be responded to with a 400 Bad Request.
Imagine, however, that collection of names, identified
by a server wanted to be "kind" URI, which are used in XML documents as element types and decided to
pick
attribute names. XML namespaces differ from the allprop element as "namespaces"
conventionally used in computing disciplines in that the true element XML version
has internal structure and respond to it. A
client running over a bandwidth limited line who intended to execute is not, mathematically speaking, a propname would be in for set.
Names from XML namespaces may appear as qualified names, which
contain a big surprise if the server treated single colon, separating the
command as an allprop.
Additionally, if name into a server were lenient namespace prefix
and decided to reply to this
request, the results would vary randomly from server a local part. The prefix, which is mapped to server, with
some servers executing a URI [RFC2396],
selects a namespace. The combination of the allprop directive, universally managed URI
namespace and others executing the propname directive. This reduces interoperability rather than
increasing it.
24.3.2.2 Example - Unknown XML Element
The previous example was illegal because it contained two elements document's own namespace produces identifiers that were explicitly banned from appearing together
are universally unique. Mechanisms are provided for prefix scoping
and defaulting to avoid clutter and improve readability.
URIs can contain characters not allowed in the propfind
element. However, XML is an extensible language, names, so one can imagine
new elements being defined cannot be used
directly as namespace prefixes. Therefore, the namespace prefix
serves as a proxy for use with propfind. Below a URI. An attribute-based syntax described
below is used to declare the
request body association of a PROPFIND and, like the previous example, must be
rejected namespace prefix
with a 400 Bad Request by a server URI; software which supports this namespace proposal must
recognize and act on these declarations and prefixes.
24.4.3 Declaring Namespaces
Note that does many of the nonterminals in the productions in section 24
of this specification are defined not understand here but in the expired-props element.
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.foo.bar/standards/props/" prefix="E"
?>
<D:propfind>
<E:expired-props/>
</D:propfind>
To understand why a 400 Bad Request is returned let us look at XML
specification [REC-XML]. When nonterminals defined here have the
request body
same names as nonterminals defined in the server unfamiliar with expired-props sees it.
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.foo.bar/standards/props/" prefix="E"
?>
<D:propfind>
</D:propfind>
As XML specification, the server does not understand
productions here in all cases match a subset of the expired-props element, strings matched
by the
rules of XML, it must ignore it. Thus corresponding ones there.
[Definition:] A namespace is declared using an attribute whose
prefix is xmlns as follows:
Namespace declaration using attributes
[1] NSDecl ::= PrefixDef Eq AttValue [ NSC: Empty URI ]
[2] PrefixDef ::= 'xmlns' (':' NCName)? [ NSC: Leading "XML" ]
[3] NCName ::= (Letter | '_') (NCNameChar)* /* An XML Name,
minus the ":" */
[4] NCNameChar ::= Letter | Digit | '.' | '-' | '_' |
CombiningChar | Extender
[Definition:] The AttValue in the server sees an empty
propfind, NSDecl production is a URI which by
functions as a namespace name to identify the definition of namespace. The
namespace name, to serve its intended purpose, should have the propfind element
characteristics of uniqueness and persistence. It is
illegal. not a goal that
Goland et al. [Page 81] 89]
INTERNET-DRAFT WebDAV April 7, October 22, 1998
Please note that had the extension been additive
it would not
necessarily have resulted in a 400 Bad Request. For example,
imagine the following request body be directly usable for a PROPFIND:
<?xml version="1.0" ?>
<?xml:namespace ns="DAV:" prefix="D" ?>
<?xml:namespace ns="http://www.foo.bar/standards/props/" prefix="E"
?>
<D:propfind>
<D:propname/>
<E:leave-out>*boss*</E:leave-out>
</D:propfind>
The previous example contains the fictitious element leave-out. Its
purpose is to prevent the return retrieval of a schema (if any property whose name matches
the submitted pattern. If the previous exists). An
example were submitted to of a
server unfamiliar syntax that is designed with leave-out, the only result would be these goals in mind is
that the
leave-out element would for Uniform Resource Names [RFC2141]. However, it should be ignored and a propname would
noted that ordinary URLs can be executed.
24.4 Appendix 4 -- XML Namespaces for WebDAV
24.4.1 Introduction
To provide a unique space of XML element names which has
decentralized extensibility, this specification uses managed in such a feature of
XML known way as XML "namespaces". This appendix provides a normative
reference for XML to achieve
these same goals.
[Definition:] In the PrefixDef production, if the optional colon and
NCName are provided, then that NCName gives the namespace functionality for implementations of prefix,
used to associate names with this specification. All DAV compliant systems MUST support the XML namespace extension as specified in this appendix.
The remainder the scope of this appendix is intended the
element to match, as closely as
needed, which the text in WD-xml-names-19980327, "Namespaces in XML",
edited by Tim Bray, Dave Hollander, declaration is attached.
[Definition:] If the colon and Andrew Layman [Bray,
Hollander, Layman, 1998]. To meet this goal, NCName are not provided, then the text in this
appendix
associated namespace name is mostly quoted verbatim from that source. The notational
conventions and BNF productions in this appendix match those of the
XML specification [Bray, Paoli, Spreberg-McQueen, 1998]
XML namespaces are based on default namespace in the use
scope of qualified names, which
contain a single colon, separating the name into a namespace prefix
and element to which the local name. declaration is attached.
Namespace Constraint: Empty URI
The prefix, which AttValue may be empty only if the PrefixDef is mapped to a URI, selects simply xmlns,
i.e. is declaring a default namespace.