Network Working Group J. Reschke, Ed.
Internet-Draft greenbytes
Expires: August 6, 2004 S. Reddy
Oracle
J. Davis
Intelligent Markets
A. Babich
Filenet
February 6, 2004
WebDAV SEARCH
draft-reschke-webdav-search-06
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at http://
www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 6, 2004.
Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This document specifies a set of methods, headers, properties and
content-types composing WebDAV SEARCH, an application of the HTTP/1.1
protocol to efficiently search for DAV resources based upon a set of
client-supplied criteria.
Distribution of this document is unlimited. Please send comments to
the Distributed Authoring and Versioning (WebDAV) DASL mailing list
Reschke, et al. Expires August 6, 2004 [Page 1]
Internet-Draft WebDAV SEARCH February 2004
at www-webdav-dasl@w3.org [1], which may be joined by sending a
message with subject "subscribe" to www-webdav-dasl-request@w3.org
[2]. Discussions of the WebDAV DASL mailing list are archived at URL:
http://lists.w3.org/Archives/Public/www-webdav-dasl/.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 DASL . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Relationship to DAV . . . . . . . . . . . . . . . . . . . 5
1.3 Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Notational Conventions . . . . . . . . . . . . . . . . . . 7
1.5 Editorial note on usage of 'DAV:' namespace . . . . . . . 7
1.6 An Overview of DASL at Work . . . . . . . . . . . . . . . 8
2. The SEARCH Method . . . . . . . . . . . . . . . . . . . . 9
2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 The Request . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.1 The Request-URI . . . . . . . . . . . . . . . . . . . . . 9
2.2.2 The Request Body . . . . . . . . . . . . . . . . . . . . . 9
2.3 The Successful 207 (Multistatus) Response . . . . . . . . 10
2.3.1 Extending the PROPFIND Response . . . . . . . . . . . . . 10
2.3.2 Example: A Simple Request and Response . . . . . . . . . . 11
2.3.3 Example: Result Set Truncation . . . . . . . . . . . . . . 12
2.4 Unsuccessful Responses . . . . . . . . . . . . . . . . . . 13
2.4.1 Example of an Invalid Scope . . . . . . . . . . . . . . . 13
3. Discovery of Supported Query Grammars . . . . . . . . . . 15
3.1 The OPTIONS Method . . . . . . . . . . . . . . . . . . . . 15
3.2 The DASL Response Header . . . . . . . . . . . . . . . . . 15
3.3 DAV:supported-query-grammar-set (protected) . . . . . . . 16
3.4 Example: Grammar Discovery . . . . . . . . . . . . . . . . 16
4. Query Schema Discovery: QSD . . . . . . . . . . . . . . . 19
4.1 Additional SEARCH semantics . . . . . . . . . . . . . . . 19
4.1.1 Example of query schema discovery . . . . . . . . . . . . 20
5. The DAV:basicsearch Grammar . . . . . . . . . . . . . . . 22
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 22
5.2 The DAV:basicsearch DTD . . . . . . . . . . . . . . . . . 22
5.2.1 Example Query . . . . . . . . . . . . . . . . . . . . . . 24
5.3 DAV:select . . . . . . . . . . . . . . . . . . . . . . . . 24
5.4 DAV:from . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.4.1 Relationship to the Request-URI . . . . . . . . . . . . . 25
5.4.2 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.5 DAV:where . . . . . . . . . . . . . . . . . . . . . . . . 25
5.5.1 Use of Three-Valued Logic in Queries . . . . . . . . . . . 26
5.5.2 Handling Optional operators . . . . . . . . . . . . . . . 26
5.5.3 Treatment of NULL Values . . . . . . . . . . . . . . . . . 26
5.5.4 Treatment of properties with mixed/element content . . . . 26
5.5.5 Example: Testing for Equality . . . . . . . . . . . . . . 26
5.5.6 Example: Relative Comparisons . . . . . . . . . . . . . . 27
Reschke, et al. Expires August 6, 2004 [Page 2]
Internet-Draft WebDAV SEARCH February 2004
5.6 DAV:orderby . . . . . . . . . . . . . . . . . . . . . . . 27
5.6.1 Comparing Natural Language Strings . . . . . . . . . . . . 28
5.6.2 Example of Sorting . . . . . . . . . . . . . . . . . . . . 28
5.7 Boolean Operators: DAV:and, DAV:or, and DAV:not . . . . . 28
5.8 DAV:eq . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.9 DAV:lt, DAV:lte, DAV:gt, DAV:gte . . . . . . . . . . . . . 29
5.10 DAV:literal . . . . . . . . . . . . . . . . . . . . . . . 29
5.11 DAV:typed-literal (optional) . . . . . . . . . . . . . . . 29
5.11.1 Example for typed numerical comparison . . . . . . . . . . 30
5.12 Support for matching xml:lang attributes on properties . . 30
5.12.1 DAV:language-defined (optional) . . . . . . . . . . . . . 30
5.12.2 DAV:language-matches (optional) . . . . . . . . . . . . . 31
5.12.3 Example of language-aware matching . . . . . . . . . . . . 31
5.13 DAV:is-collection . . . . . . . . . . . . . . . . . . . . 31
5.13.1 Example of DAV:is-collection . . . . . . . . . . . . . . . 31
5.14 DAV:is-defined . . . . . . . . . . . . . . . . . . . . . . 32
5.15 DAV:like . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.15.1 Syntax for the Literal Pattern . . . . . . . . . . . . . . 32
5.15.2 Example of DAV:like . . . . . . . . . . . . . . . . . . . 33
5.16 DAV:contains . . . . . . . . . . . . . . . . . . . . . . . 33
5.16.1 Result scoring (DAV:score element) . . . . . . . . . . . . 34
5.16.2 Ordering by score . . . . . . . . . . . . . . . . . . . . 34
5.16.3 Examples . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.17 Limiting the result set . . . . . . . . . . . . . . . . . 35
5.17.1 Relationship to result ordering . . . . . . . . . . . . . 35
5.18 The 'caseless' XML attribute . . . . . . . . . . . . . . . 35
5.19 Query schema for DAV:basicsearch . . . . . . . . . . . . . 35
5.19.1 DTD for DAV:basicsearch QSD . . . . . . . . . . . . . . . 36
5.19.2 DAV:propdesc Element . . . . . . . . . . . . . . . . . . . 36
5.19.3 The DAV:datatype Property Description . . . . . . . . . . 37
5.19.4 The DAV:searchable Property Description . . . . . . . . . 37
5.19.5 The DAV:selectable Property Description . . . . . . . . . 37
5.19.6 The DAV:sortable Property Description . . . . . . . . . . 38
5.19.7 The DAV:caseless Property Description . . . . . . . . . . 38
5.19.8 The DAV:operators XML Element . . . . . . . . . . . . . . 38
5.19.9 Example of Query Schema for DAV:basicsearch . . . . . . . 39
6. Internationalization Considerations . . . . . . . . . . . 40
7. Security Considerations . . . . . . . . . . . . . . . . . 41
7.1 Implications of XML External Entities . . . . . . . . . . 41
8. Scalability . . . . . . . . . . . . . . . . . . . . . . . 42
9. Authentication . . . . . . . . . . . . . . . . . . . . . . 43
10. IANA Considerations . . . . . . . . . . . . . . . . . . . 44
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . 45
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . 46
Normative References . . . . . . . . . . . . . . . . . . . 47
Informative References . . . . . . . . . . . . . . . . . . 48
Authors' Addresses . . . . . . . . . . . . . . . . . . . . 49
A. Three-Valued Logic in DAV:basicsearch . . . . . . . . . . 50
Reschke, et al. Expires August 6, 2004 [Page 3]
Internet-Draft WebDAV SEARCH February 2004
B. Change Log (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . . . . 52
B.1 From draft-davis-dasl-protocol-xxx . . . . . . . . . . . . 52
B.2 since start of draft-reschke-webdav-search . . . . . . . . 53
B.3 since draft-reschke-webdav-search-00 . . . . . . . . . . . 55
B.4 since draft-reschke-webdav-search-01 . . . . . . . . . . . 55
B.5 since draft-reschke-webdav-search-02 . . . . . . . . . . . 56
B.6 since draft-reschke-webdav-search-03 . . . . . . . . . . . 56
B.7 since draft-reschke-webdav-search-04 . . . . . . . . . . . 57
B.8 since draft-reschke-webdav-search-05 . . . . . . . . . . . 57
C. Resolved issues (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . . . . 59
C.1 5.4.2-multiple-scope . . . . . . . . . . . . . . . . . . . 59
D. Open issues (to be removed by RFC Editor prior to
publication) . . . . . . . . . . . . . . . . . . . . . . . 60
D.1 1.3-apply-condition-code-terminology . . . . . . . . . . . 60
D.2 2.4-multiple-uris . . . . . . . . . . . . . . . . . . . . 60
D.3 result-truncation . . . . . . . . . . . . . . . . . . . . 60
D.4 qsd-optional . . . . . . . . . . . . . . . . . . . . . . . 61
D.5 5.1-name-filtering . . . . . . . . . . . . . . . . . . . . 61
D.6 5_media_type_match . . . . . . . . . . . . . . . . . . . . 62
D.7 5.4.2-scope-vs-redirects . . . . . . . . . . . . . . . . . 62
D.8 language-comparison . . . . . . . . . . . . . . . . . . . 62
D.9 JW16b/JW24a . . . . . . . . . . . . . . . . . . . . . . . 63
D.10 typed-literal . . . . . . . . . . . . . . . . . . . . . . 63
Index . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Intellectual Property and Copyright Statements . . . . . . 66
Reschke, et al. Expires August 6, 2004 [Page 4]
Internet-Draft WebDAV SEARCH February 2004
1. Introduction
1.1 DASL
This document defines WebDAV SEARCH, an application of HTTP/1.1
forming a lightweight search protocol to transport queries and result
sets and allows clients to make use of server-side search facilities.
It is based on the expired draft for WebDAV DASL [DASL]. [DASLREQ]
describes the motivation for DASL.
DASL will minimize the complexity of clients so as to facilitate
widespread deployment of applications capable of utilizing the DASL
search mechanisms.
DASL consists of:
o the SEARCH method,
o the DASL response header,
o the DAV:searchrequest XML element,
o the DAV:query-schema-discovery XML element,
o the DAV:basicsearch XML element and query grammar, and
o the DAV:basicsearchschema XML element.
For WebDAV-compliant servers, it also defines a new live property
DAV:supported-query-grammar-set.
1.2 Relationship to DAV
DASL relies on the resource and property model defined by [RFC2518].
DASL does not alter this model. Instead, DASL allows clients to
access DAV-modeled resources through server-side search.
1.3 Terms
This document uses the terms defined in [RFC2616], in [RFC2518], in
[RFC3253] and in this section.
Criteria
An expression against which each resource in the search scope is
evaluated.
Query
Reschke, et al. Expires August 6, 2004 [Page 5]
Internet-Draft WebDAV SEARCH February 2004
A query is a combination of a search scope, search criteria,
result record definition, sort specification, and a search
modifier.
Query Grammar
A set of definitions of XML elements, attributes, and constraints
on their relations and values that defines a set of queries and
the intended semantics.
Query Schema
A listing, for any given grammar and scope, of the properties and
operators that may be used in a query with that grammar and scope.
Result
A result is a result set, optionally augmented with other
information describing the search as a whole.
Result Record
A description of a resource. A result record is a set of
properties, and possibly other descriptive information.
Result Record Definition
A specification of the set of properties to be returned in the
result record.
Result Set
A set of records, one for each resource for which the search
criteria evaluated to True.
Scope
A set of resources to be searched.
Search Modifier
An instruction that governs the execution of the query but is not
part of the search scope, result record definition, the search
criteria, or the sort specification. An example of a search
modifier is one that controls how much time the server can spend
on the query before giving a response.
Sort Specification
Reschke, et al. Expires August 6, 2004 [Page 6]
Internet-Draft WebDAV SEARCH February 2004
A specification of an ordering on the result records in the result
set.
1.4 Notational Conventions
The augmented BNF used by this document to describe protocol elements
is exactly the same as the one described in Section 2.1 of [RFC2616].
Because this augmented BNF uses the basic production rules provided
in Section 2.2 of [RFC2616], those 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 [RFC2119].
This document uses XML DTD fragments as a purely notational
convention. WebDAV request and response bodies can not be validated
due to the specific extensibility rules defined in section 23 of
[RFC2518] and due to the fact that all XML elements defined by this
specification use the XML namespace name "DAV:". In particular:
1. element names use the "DAV:" namespace,
2. element ordering is irrelevant unless explicitly stated,
3. extension elements (elements not already defined as valid child
elements) may be added anywhere, except when explicitly stated
otherwise,
4. extension attributes (attributes not already defined as valid for
this element) may be added anywhere, except when explicitly
stated otherwise.
When an XML element type in the "DAV:" namespace is referenced in
this document outside of the context of an XML fragment, the string
"DAV:" will be prefixed to the element type.
Similarily, when an XML element type in the namespace "http://
www.w3.org/2001/XMLSchema" is referenced in this document outside of
the context of an XML fragment, the string "xs:" will be prefixed to
the element type.
1.5 Editorial note on usage of 'DAV:' namespace
*Note that this draft currently defines elements and properties in
the WebDAV namespace "DAV:" which it shouldn't do as it isn't a work
item of the WebDAV working group. The reason for this is the desire
Reschke, et al. Expires August 6, 2004 [Page 7]
Internet-Draft WebDAV SEARCH February 2004
for some kind of backward compatibility to the expired DASL drafts
and the assumption that the draft may become an official RFC
submission of the WebDAV working group at a later point of time.*
1.6 An Overview of DASL at Work
One can express the basic usage of DASL in the following steps:
o The client constructs a query using the DAV:basicsearch grammar.
o The client invokes the SEARCH method on a resource that will
perform the search (the search arbiter) and includes a text/xml or
application/xml request entity that contains the query.
o The search arbiter performs the query.
o The search arbiter sends the results of the query back to the
client in the response. The server MUST send an entity that
matches the [RFC2518] PROPFIND response.
Reschke, et al. Expires August 6, 2004 [Page 8]
Internet-Draft WebDAV SEARCH February 2004
2. The SEARCH Method
2.1 Overview
The client invokes the SEARCH method to initiate a server-side
search. The body of the request defines the query. The server MUST
emit an entity matching the [RFC2518] PROPFIND response.
The SEARCH method plays the role of transport mechanism for the query
and the result set. It does not define the semantics of the query.
The type of the query defines the semantics.
2.2 The Request
The client invokes the SEARCH method on the resource named by the
Request-URI.
2.2.1 The Request-URI
The Request-URI identifies the search arbiter. Any HTTP resource may
function as search arbiter. It is not a new type of resource (in the
sense of DAV:resourcetype as defined in [RFC2518]), nor does it have
to be a WebDAV-compliant resource.
The SEARCH method defines no relationship between the arbiter and the
scope of the search, rather the particular query grammar used in the
query defines the relationship. For example, a query grammar may
force the request-URI to correspond exactly to the search scope.
2.2.2 The Request Body
The server MUST process a text/xml or application/xml request body,
and MAY process request bodies in other formats. See [RFC3023] for
guidance on packaging XML in requests.
Marshalling:
If a request body with content type text/xml or application/xml is
included, it MUST be either a DAV:searchrequest or a
DAV:query-schema-discovery XML element. It's single child element
identifies the query grammar.
For DAV:searchrequest, the definition of search criteria, the
result record, and any other details needed to perform the search
depend on the individual search grammar.
For DAV:query-schema-discovery, the semantics is defined in
Section 4.
Reschke, et al. Expires August 6, 2004 [Page 9]
Internet-Draft WebDAV SEARCH February 2004
Preconditions:
(DAV:search-grammar-discovery-supported): when an XML request body
is present and has a DAV:query-schema-discovery document element,
the server MUST support the query schema discovery mechanism
described in Section 4.
(DAV:search-grammar-supported): when an XML request body is
present, the search grammar identified by the document element's
child element must be a supported search grammar.
(DAV:search-multiple-scope-supported): if the SEARCH request
specified multiple scopes, the server MUST support this optional
feature.
(DAV:search-scope-valid): the supplied search scope must be valid.
There can be various reasons for a search scope to be invalid,
including unsupported URI schemes and communication problems.
Servers MAY add [RFC2518] compliant DAV:response elements as
content to the condition element indicating the precise reason for
the failure.
2.3 The Successful 207 (Multistatus) Response
If the server returns 207 (Multistatus), then the search proceeded
successfully and the response MUST match that of a PROPFIND. The
results of this method SHOULD NOT be cached.
There MUST be one DAV:response for each resource that matched the
search criteria. For each such response, the DAV:href element
contains the URI of the resource, and the response MUST include a
DAV:propstat element.
Note that for each matching resource found there may be multiple URIs
within the search scope mapped to it. In this case, a server SHOULD
report all of these URIs. Clients can use the live property
DAV:resource-id defined in [BIND] to identify possible duplicates.
2.3.1 Extending the PROPFIND Response
A response MAY include more information than PROPFIND defines so long
as the extra information does not invalidate the PROPFIND response.
Query grammars SHOULD define how the response matches the PROPFIND
response.
Reschke, et al. Expires August 6, 2004 [Page 10]
Internet-Draft WebDAV SEARCH February 2004
2.3.2 Example: A Simple Request and Response
This example demonstrates the request and response framework. The
following XML document shows a simple (hypothetical) natural language
query. The name of the query element is natural-language-query in the
XML namespace "http://example.com/foo". The actual query is "Find the
locations of good Thai restaurants in Los Angeles". For this
hypothetical query, the arbiter returns two properties for each
selected resource.
>> Request:
SEARCH / HTTP/1.1
Host: example.org
Content-Type: application/xml
Content-Length: xxx
<?xml version="1.0" encoding="UTF-8"?>
<D:searchrequest xmlns:D="DAV:" xmlns:F="http://example.com/foo">
<F:natural-language-query>
Find the locations of good Thai restaurants in Los Angeles
</F:natural-language-query>
</D:searchrequest>
>> Response:
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxx
<?xml version="1.0" encoding="UTF-8"?>
<D:multistatus xmlns:D="DAV:"
xmlns:R="http://example.org/propschema">
<D:response>
<D:href>http://siamiam.test/</D:href>
<D:propstat>
<D:prop>
<R:location>259 W. Hollywood</R:location>
<R:rating><R:stars>4</R:stars></R:rating>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
Reschke, et al. Expires August 6, 2004 [Page 11]
Internet-Draft WebDAV SEARCH February 2004
2.3.3 Example: Result Set Truncation
A server MAY limit the number of resources in a reply, for example to
limit the amount of resources expended in processing a query. If it
does so, the reply MUST use status code 207, return a DAV:multistatus
response body and indicate a status of 507 (Insufficient Storage) for
the search arbiter URI. It SHOULD include the partial results.
When a result set is truncated, there may be many more resources that
satisfy the search criteria but that were not examined.
If partial results are included and the client requested an ordered
result set in the original request, then any partial results that are
returned MUST be ordered as the client directed.
Note that the partial results returned MAY be any subset of the
result set that would have satisfied the original query.
>> Request:
SEARCH / HTTP/1.1
Host: example.net
Content-Type: text/xml; charset="utf-8"
Content-Length: xxx
... the query goes here ...
Reschke, et al. Expires August 6, 2004 [Page 12]
Internet-Draft WebDAV SEARCH February 2004
>> Response:
HTTP/1.1 207 Multistatus
Content-Type: text/xml; charset="utf-8"
Content-Length: xxx
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>http://www.example.net/sounds/unbrokenchain.au</D:href>
<D:propstat>
<D:prop/>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>http://tech.mit.test/archive96/photos/Lesh1.jpg</D:href>
<D:propstat>
<D:prop/>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>http://example.net</D:href>
<D:status>HTTP/1.1 507 Insufficient Storage</D:status>
<D:responsedescription xml:lang="en">
Only first two matching records were returned
</D:responsedescription>
</D:response>
</D:multistatus>
2.4 Unsuccessful Responses
If a SEARCH request could not be executed or the attempt to execute
it resulted in an error, the server MUST indicate the failure with an
appropriate status code and SHOULD add a response body as defined in
[RFC3253], section 1.6. Unless otherwise stated, condition elements
are empty, however specific conditions element MAY include additional
child elements that describe the error condition in more detail.
2.4.1 Example of an Invalid Scope
In the example below, a request failed because the scope identifies a
HTTP resource that was not found.
Reschke, et al. Expires August 6, 2004 [Page 13]
Internet-Draft WebDAV SEARCH February 2004
>> Response:
HTTP/1.1 409 Conflict
Content-Type: text/xml; charset="utf-8"
Content-Length: xxx
<?xml version="1.0" encoding="UTF-8"?>
<d:error xmlns:d="DAV:">
<d:search-scope-valid>
<d:response>
<d:href>http://www.example.com/X</d:href>
<d:status>HTTP/1.1 404 Object Not Found</d:status>
</d:response>
</d:search-scope-valid>
</d:error>
Reschke, et al. Expires August 6, 2004 [Page 14]
Internet-Draft WebDAV SEARCH February 2004
3. Discovery of Supported Query Grammars
Servers MUST support discovery of the query grammars supported by a
search arbiter resource.
Clients can determine which query grammars are supported by an
arbiter by invoking OPTIONS on the search arbiter. If the resource
supports SEARCH, then the DASL response header will appear in the
response. The DASL response header lists the supported grammars.
Servers supporting the WebDAV extensions [RFC3253] and/or [ACL] MUST
also
o report SEARCH in the live property DAV:supported-method-set for
all search arbiter resources and
o support the live property DAV:supported-query-grammar-set as
defined in Section 3.3.
3.1 The OPTIONS Method
The OPTIONS method allows the client to discover if a resource
supports the SEARCH method and to determine the list of search
grammars supported for that resource.
The client issues the OPTIONS method against a resource named by the
Request-URI. This is a normal invocation of OPTIONS defined in
[RFC2616].
If a resource supports the SEARCH method, then the server MUST list
SEARCH in the OPTIONS response as defined by [RFC2616].
DASL servers MUST include the DASL header in the OPTIONS response.
This header identifies the search grammars supported by that
resource.
3.2 The DASL Response Header
DASLHeader = "DASL" ":" Coded-URL-List
Coded-URL-List : Coded-URL [ "," Coded-URL-List ]
Coded-URL ; defined in section 9.4 of [RFC2518]
The DASL response header indicates server support for a query grammar
in the OPTIONS method. The value is a URI that indicates the type of
grammar. Note that although the URI can be used to identify each
supported search grammar, there is not necessarily a direct
relationship between the URI and the XML element name that can be
Reschke, et al. Expires August 6, 2004 [Page 15]
Internet-Draft WebDAV SEARCH February 2004
used in XML based SEARCH requests (the element name itself is
identified by it's namespace name (a URI reference) and the element's
local name).
This header MAY be repeated.
For example:
DASL: <http://foobar.test/syntax1>
DASL: <http://akuma.test/syntax2>
DASL: <DAV:basicsearch>
DASL: <http://example.com/foo/natural-language-query>
3.3 DAV:supported-query-grammar-set (protected)
This WebDAV property is required for any server supporting either
[RFC3253] and/or [ACL] and identifies the XML based query grammars
that are supported by the search arbiter resource.
<!ELEMENT supported-query-grammar-set (supported-query-grammar*)>
<!ELEMENT supported-query-grammar grammar>
<!ELEMENT grammar ANY>
ANY value: a query grammar element type
3.4 Example: Grammar Discovery
This example shows that the server supports search on the /somefolder
resource with the query grammars: DAV:basicsearch, http://
foobar.test/syntax1 and http://akuma.test/syntax2. Note that every
server MUST support DAV:basicsearch.
>> Request:
OPTIONS /somefolder HTTP/1.1
Host: example.org
>> Response:
HTTP/1.1 200 OK
Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE
Allow: MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, SEARCH
DASL: <DAV:basicsearch>
DASL: <http://foobar.test/syntax1>
DASL: <http://akuma.test/syntax2>
This example shows the equivalent taking advantage of a server's
Reschke, et al. Expires August 6, 2004 [Page 16]
Internet-Draft WebDAV SEARCH February 2004
support for DAV:supported-method-set and
DAV:supported-query-grammar-set.
>> Request:
PROPFIND /somefolder HTTP/1.1
Host: example.org
Depth: 0
Content-Type: text/xml; charset="utf-8"
Content-Length: xxx
<?xml version="1.0" encoding="UTF-8" ?>
<propfind xmlns="DAV:">
<prop>
<supported-query-grammar-set/>
<supported-method-set/>
</prop>
</propfind>
>> Response:
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?>
<multistatus xmlns="DAV:">
<response>
<href>http://example.org/somefolder</href>
<propstat>
<prop>
<supported-query-grammar-set>
<supported-query-grammar>
<grammar><basicsearch/></grammar>
</supported-query-grammar>
<supported-query-grammar>
<grammar><syntax1 xmlns="http://foobar.test" /></grammar>
</supported-query-grammar>
<supported-query-grammar>
<grammar><syntax2 xmlns="http://akuma.test/"/></grammar>
</supported-query-grammar>
</supported-query-grammar-set>
<supported-method-set>
<supported-method name="COPY" />
<supported-method name="DELETE" />
<supported-method name="GET" />
<supported-method name="HEAD" />
<supported-method name="LOCK" />
Reschke, et al. Expires August 6, 2004 [Page 17]
Internet-Draft WebDAV SEARCH February 2004
<supported-method name="MKCOL" />
<supported-method name="MOVE" />
<supported-method name="OPTIONS" />
<supported-method name="POST" />
<supported-method name="PROPFIND" />
<supported-method name="PROPPATCH" />
<supported-method name="PUT" />
<supported-method name="SEARCH" />
<supported-method name="TRACE" />
<supported-method name="UNLOCK" />
</supported-method-set>
</prop>
<status>HTTP/1.1 200 OK</status>
</propstat>
</response>
</multistatus>
Note that the query grammar element names marshalled as part of the
DAV:supported-query-grammar-set can be directly used as element names
in an XML based query.
Reschke, et al. Expires August 6, 2004 [Page 18]
Internet-Draft WebDAV SEARCH February 2004
4. Query Schema Discovery: QSD
Servers MAY support the discovery of the schema for a query grammar.
The DASL response header and the DAV:supported-query-grammar-set
property provide means for clients to discover the set of query
grammars supported by a resource. This alone is not sufficient
information for a client to generate a query. For example, the
DAV:basicsearch grammar defines a set of queries consisting of a set
of operators applied to a set of properties and values, but the
grammar itself does not specify which properties may be used in the
query. QSD for the DAV:basicsearch grammar allows a client to
discover the set of properties that are searchable, selectable, and
sortable. Moreover, although the DAV:basicsearch grammar defines a
minimal set of operators, it is possible that a resource might
support additional operators in a query. For example, a resource
might support a optional operator that can be used to express
content-based queries in a proprietary syntax. QSD allows a client to
discover these operators and their syntax. The set of discoverable
quantities will differ from grammar to grammar, but each grammar can
define a means for a client to discover what can be discovered.
In general, the schema for a given query grammar depends on both the
resource (the arbiter) and the scope. A given resource might have
access to one set of properties for one potential scope, and another
set for a different scope. For example, consider a server able to
search two distinct collections, one holding cooking recipes, the
other design documents for nuclear weapons. While both collections
might support properties such as author, title, and date, the first
might also define properties such as calories and preparation time,
while the second defined properties such as yield and applicable
patents. Two distinct arbiters indexing the same collection might
also have access to different properties. For example, the recipe
collection mentioned above might also indexed by a value-added server
that also stored the names of chefs who had tested the recipe. Note
also that the available query schema might also depend on other
factors, such as the identity of the principal conducting the search,
but these factors are not exposed in this protocol.
4.1 Additional SEARCH semantics
Each query grammar supported by DASL defines its own syntax for
expressing the possible query schema. A client retrieves the schema
for a given query grammar on an arbiter resource with a given scope
by invoking the SEARCH method on that arbiter with that grammar and
scope and with a root element of DAV:query-schema-discovery rather
than DAV:searchrequest.
Reschke, et al. Expires August 6, 2004 [Page 19]
Internet-Draft WebDAV SEARCH February 2004
Marshalling:
The request body MUST be DAV:query-schema-discovery element.
<!ELEMENT query-schema-discovery ANY>
ANY value: XML element defining a valid query
The response body takes the form of a RFC2518 DAV:multistatus
element, where DAV:response is extended to hold the returned query
grammar inside a DAV:query-schema container element.
<!ELEMENT response (href, ((href*, status)|(propstat+)),
query-schema?, responsedescription?) >
<!ELEMENT query-schema ANY>
The content of this container is an XML element whose name and syntax
depend upon the grammar, and whose value may (and likely will) vary
depending upon the grammar, arbiter, and scope.
4.1.1 Example of query schema discovery
In this example, the arbiter is recipes.test, the grammar is
DAV:basicsearch, the scope is also recipes.test.
>> Request:
SEARCH / HTTP/1.1
Host: recipes.test
Content-Type: application/xml
Content-Length: xxx
<?xml version="1.0"?>
<query-schema-discovery xmlns="DAV:">
<basicsearch>
<from>
<scope>
<href>http://recipes.test</href>
<depth>infinity</depth>
</scope>
</from>
</basicsearch>
</query-schema-discovery>
Reschke, et al. Expires August 6, 2004 [Page 20]
Internet-Draft WebDAV SEARCH February 2004
>> Response:
HTTP/1.1 207 Multistatus
Content-Type: application/xml
Content-Length: xxx
<?xml version="1.0"?>
<multistatus xmlns="DAV:">
<response>
<href>http://recipes.test</href>
<status>HTTP/1.1 200 OK</status>
<query-schema>
<basicsearchschema>
<!-- (See section "Query schema for DAV:basicsearch" for
the actual contents) -->
</basicsearchschema>
</query-schema>
</response>
</multistatus>
The query schema for DAV:basicsearch is defined in Section 5.19.
Reschke, et al. Expires August 6, 2004 [Page 21]
Internet-Draft WebDAV SEARCH February 2004
5. The DAV:basicsearch Grammar
5.1 Introduction
DAV:basicsearch uses an extensible XML syntax that allows clients to
express search requests that are generally useful for WebDAV
scenarios. DASL-extended servers MUST accept this grammar, and MAY
accept other grammars.
DAV:basicsearch has several components:
o DAV:select provides the result record definition.
o DAV:from defines the scope.
o DAV:where defines the criteria.
o DAV:orderby defines the sort order of the result set.
o DAV:limit provides constraints on the query as a whole.
5.2 The DAV:basicsearch DTD
<!-- "basicsearch" element -->
<!ELEMENT basicsearch (select, from, where?, orderby?, limit?) >
<!-- "select" element -->
<!ELEMENT select (allprop | prop) >
<!-- "from" element -->
<!ELEMENT from (scope+) >
<!ELEMENT scope (href, depth) >
<!-- "where" element -->
<!ENTITY %comp_ops "eq | lt | gt| lte | gte">
<!ENTITY %log_ops "and | or | not">
<!ENTITY %special_ops "is-collection | is-defined |
language-defined | language-matches">
<!ENTITY %string_ops "like">
<!ENTITY %content_ops "contains">
<!ENTITY %all_ops "%comp_ops; | %log_ops; | %special_ops; |
%string_ops; | %content_ops;">
Reschke, et al. Expires August 6, 2004 [Page 22]
Internet-Draft WebDAV SEARCH February 2004
<!ELEMENT where ( %all_ops; ) >
<!ELEMENT and ( ( %all_ops; ) +) >
<!ELEMENT or ( ( %all_ops; ) +) >
<!ELEMENT not ( %all_ops; ) >
<!ELEMENT lt (prop, (literal|typed-literal)) >
<!ATTLIST lt caseless (yes|no) >
<!ELEMENT lte (prop, (literal|typed-literal)) >
<!ATTLIST lte caseless (yes|no) >
<!ELEMENT gt (prop, (literal|typed-literal)) >
<!ATTLIST gt caseless (yes|no) >
<!ELEMENT gte (prop, (literal|typed-literal)) >
<!ATTLIST gte caseless (yes|no) >
<!ELEMENT eq (prop, (literal|typed-literal)) >
<!ATTLIST eq caseless (yes|no) >
<!ELEMENT literal (#PCDATA)>
<!ELEMENT typed-literal (#PCDATA)>
<!ATTLIST typed-literal xsi:type CDATA implied>
<!ELEMENT is-collection (prop) >
<!ELEMENT is-defined (prop) >
<!ELEMENT language-defined (prop) >
<!ELEMENT language-matches (prop, literal) >
<!ELEMENT like (prop, literal) >
<!ATTLIST like caseless (yes|no) >
<!ELEMENT contains (#PCDATA)>
<!-- "orderby" element -->
<!ELEMENT orderby (order+) >
<!ELEMENT order ((prop | score), (ascending | descending)?)
<!ATTLIST order caseless (yes|no) >
<!ELEMENT ascending EMPTY>
<!ELEMENT descending EMPTY>
Reschke, et al. Expires August 6, 2004 [Page 23]
Internet-Draft WebDAV SEARCH February 2004
<!-- "limit" element -->
<!ELEMENT limit (nresults) >
<!ELEMENT nresults (#PCDATA) >
5.2.1 Example Query
This query retrieves the content length values for all resources
located under the server's "/container1/" URI namespace whose length
exceeds 10000.
<d:searchrequest xmlns:d="DAV:">
<d:basicsearch>
<d:select>
<d:prop><d:getcontentlength/></d:prop>
</d:select>
<d:from>
<d:scope>
<d:href>/container1/</d:href>
<d:depth>infinity</d:depth>
</d:scope>
</d:from>
<d:where>
<d:gt>
<d:prop><d:getcontentlength/></d:prop>
<d:literal>10000</d:literal>
</d:gt>
</d:where>
<d:orderby>
<d:order>
<d:prop><d:getcontentlength/></d:prop>
<d:ascending/>
</d:order>
</d:orderby>
</d:basicsearch>
</d:searchrequest>
5.3 DAV:select
DAV:select defines the result record, which is a set of properties
and values. This document defines two possible values: DAV:allprop
and DAV:prop, both defined in [RFC2518] and revised in [RFC3253].
5.4 DAV:from
<!ELEMENT scope (href, depth, include-versions?) >
Reschke, et al. Expires August 6, 2004 [Page 24]
Internet-Draft WebDAV SEARCH February 2004
<!ELEMENT include-versions EMPTY >
DAV:from defines the query scope. This contains one or more DAV:scope
elements. Support for multiple scope elements is optional, however
servers MUST fail a request specifying multiple DAV:scope elements if
they can't support it (see Section 2.2.2, precondition
DAV:search-multiple-scope-supported). The scope element contains
mandatory DAV:href and DAV:depth elements.
DAV:href indicates the URI to use as a scope.
When the scope is a collection, if DAV:depth is "0", the search
includes only the collection. When it is "1", the search includes the
(toplevel) members of the collection. When it is "infinity", the
search includes all recursive members of the collection.
When the scope is not a collection, the depth is ignored and the
search applies just to the resource itself.
When the child element DAV:include-versions is present, the search
scope will include all versions (see [RFC3253], section 2.2.1) of all
version-controlled resources in scope. Servers that do support
versioning but do not support the DAV:include-versions feature MUST
signal an error if it is used in a query.
5.4.1 Relationship to the Request-URI
If the DAV:scope element is an absolute URI, the scope is exactly
that URI.
If the DAV:scope element is is an absolute URI reference, the scope
is taken to be relative to the request-URI.
5.4.2 Scope
A Scope can be an arbitrary URI.
Servers, of course, may support only particular scopes. This may
include limitations for particular schemes such as "http:" or "ftp:"
or certain URI namespaces.
5.5 DAV:where
The DAV:where element defines the search condition for inclusion of
resources in the result set. The value of this element is an XML
element that defines a search operator that evaluates to one of the
Boolean truth values TRUE, FALSE, or UNKNOWN. The search operator
contained by DAV:where may itself contain and evaluate additional
Reschke, et al. Expires August 6, 2004 [Page 25]
Internet-Draft WebDAV SEARCH February 2004
search operators as operands, which in turn may contain and evaluate
additional search operators as operands, etc. recursively.
5.5.1 Use of Three-Valued Logic in Queries
Each operator defined for use in the where clause that returns a
Boolean value MUST evaluate to TRUE, FALSE, or UNKNOWN. The resource
under scan is included as a member of the result set if and only if
the search condition evaluates to TRUE.
Consult Appendix A for details on the application of three-valued
logic in query expressions.
5.5.2 Handling Optional operators
If a query contains an operator that is not supported by the server,
then the server MUST respond with a 422 (Unprocessable Entity) status
code.
5.5.3 Treatment of NULL Values
If a PROPFIND for a property value would yield a non-2xx (see
[RFC2616], section 10.2) response for that property, then that
property is considered NULL.
NULL values are "less than" all other values in comparisons.
Empty strings (zero length strings) are not NULL values. An empty
string is "less than" a string with length greater than zero.
The DAV:is-defined operator is defined to test if the value of a
property is NULL.
5.5.4 Treatment of properties with mixed/element content
Comparisons of properties that do not have simple types (text-only
content) is out-of-scope for the standard operators defined for
DAV:basicsearch and therefore is defined to be UNKNOWN (as per
Appendix A). For querying the DAV:resourcetype property, see Section
5.13.
5.5.5 Example: Testing for Equality
The example shows a single operator (DAV:eq) applied in the criteria.
Reschke, et al. Expires August 6, 2004 [Page 26]
Internet-Draft WebDAV SEARCH February 2004
<d:where>
<d:eq>
<d:prop>
<d:getcontentlength/>
</d:prop>
<d:literal>100</d:literal>
</d:eq>
</d:where>
5.5.6 Example: Relative Comparisons
The example shows a more complex operation involving several
operators (DAV:and, DAV:eq, DAV:gt) applied in the criteria. This
DAV:where expression matches those resources that are "image/gifs"
over 4K in size.
<D:where>
<D:and>
<D:eq>
<D:prop>
<D:getcontenttype/>
</D:prop>
<D:literal>image/gif</D:literal>
</D:eq>
<D:gt>
<D:prop>
<D:getcontentlength/>
</D:prop>
<D:literal>4096</D:literal>
</D:gt>
</D:and>
</D:where>
5.6 DAV:orderby
The DAV:orderby element specifies the ordering of the result set. It
contains one or more DAV:order elements, each of which specifies a
comparison between two items in the result set. Informally, a
comparison specifies a test that determines whether one resource
appears before another in the result set. Comparisons are applied in
the order they occur in the DAV:orderby element, earlier comparisons
being more significant.
The comparisons defined here use only a single property from each
resource, compared using the same ordering as the DAV:lt operator
(ascending) or DAV:gt operator (descending). If neither direction is
specified, the default is DAV:ascending.
Reschke, et al. Expires August 6, 2004 [Page 27]
Internet-Draft WebDAV SEARCH February 2004
In the context of the DAV:orderby element, null values are considered
to collate before any actual (i.e., non null) value, including
strings of zero length (this is compatible with [SQL99]).
5.6.1 Comparing Natural Language Strings
Comparisons on strings take into account the language defined for
that property. Clients MAY specify the language using the xml:lang
attribute. If no language is specified either by the client or
defined for that property by the server or if a comparison is
performed on strings of two different languages, the results are
undefined.
The "caseless" attribute may be used to indicate case-sensitivity for
comparisons.
5.6.2 Example of Sorting
This sort orders first by last name of the author, and then by size,
in descending order, so that for each author, the largest works
appear first.
<d:orderby>
<d:order>
<d:prop><r:lastname/></d:prop>
<d:ascending/>
</d:order>
<d:order>
<d:prop><d:getcontentlength/></d:prop>
<d:descending/>
</d:order>
</d:orderby>
5.7 Boolean Operators: DAV:and, DAV:or, and DAV:not
The DAV:and operator performs a logical AND operation on the
expressions it contains.
The DAV:or operator performs a logical OR operation on the values it
contains.
The DAV:not operator performs a logical NOT operation on the values
it contains.
5.8 DAV:eq
The DAV:eq operator provides simple equality matching on property
values.
Reschke, et al. Expires August 6, 2004 [Page 28]
Internet-Draft WebDAV SEARCH February 2004
The "caseless" attribute may be used with this element.
5.9 DAV:lt, DAV:lte, DAV:gt, DAV:gte
The DAV:lt, DAV:lte, DAV:gt, and DAV:gte operators provide
comparisons on property values, using less-than, less-than or equal,
greater-than, and greater-than or equal respectively. The "caseless"
attribute may be used with these elements.
5.10 DAV:literal
DAV:literal allows literal values to be placed in an expression.
White space in literal values is significant in comparisons. For
consistency with [RFC2518], clients SHOULD NOT specify the attribute
"xml:space" (section 2.10 of [XML]) to override this behaviour.
In comparisons, the contents of DAV:literal SHOULD be treated as
string, with the following exceptions:
o when operand for a comparison with a DAV:getcontentlength
property, it SHOULD be treated as an integer value (the behaviour
for non-integer values is undefined),
o when operand for a comparison with a DAV:creationdate or
DAV:getlastmodified property, it SHOULD be treated as a date value
in the ISO-8601 subset defined for the DAV:creationdate property
([RFC2518], section 13.1).
o when operand for a comparison with a property for which the type
is known, it MAY be treated according to this type.
5.11 DAV:typed-literal (optional)
There are situations in which a client may want to force a comparison
not to be string-based (as defined for DAV:literal). In these cases,
a typed comparison can be enforced by using DAV:typed-literal
instead.
<!ELEMENT typed-literal (#PCDATA)>
The data type is specified using the xsi:type attribute defined in
[XS1], section 2.6.1. If the type is not specified, it defaults to
"xs:string".
A server MUST reject a request with an unknown type.
Reschke, et al. Expires August 6, 2004 [Page 29]
Internet-Draft WebDAV SEARCH February 2004
5.11.1 Example for typed numerical comparison
Consider a set of resources with the dead property "edits" in the
namespace "http://ns.example.org":
+-----+----------------+
| URI | property value |
+-----+----------------+
| /a | "-1" |
| | |
| /b | "01" |
| | |
| /c | "3" |
| | |
| /d | "test" |
| | |
| /e | (undefined) |
+-----+----------------+
The expression
<lt xmlns="DAV:"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<prop><edits xmlns="http://ns.example.org"/></prop>
<typed-literal xsi:type="xs:integer">3</typed-literal>
</lt>
will evaluate to TRUE for the resources "/a" and "/b" (their property
values can be parsed as type xs:number, and the numerical comparison
evaluates to true), to FALSE for "/c" (property value is compatible,
but numerical comparison evaluates to false) and UNKNOWN for "/d" and
"/e" (the property either is undefined, or its value can not be
parsed as xs:number).
5.12 Support for matching xml:lang attributes on properties
The following two optional operators can be used to express
conditions on the language of a property value (as expressed using
the xml:lang attribute).
5.12.1 DAV:language-defined (optional)
<!ELEMENT language-defined (prop)>
This operator evaluates to TRUE if the language for the value of the
given property is known, FALSE if it isn't and UNKNOWN if the
property itself is not defined.
Reschke, et al. Expires August 6, 2004 [Page 30]
Internet-Draft WebDAV SEARCH February 2004
5.12.2 DAV:language-matches (optional)
<!ELEMENT language-matches (prop, literal)>
This operator evaluates to TRUE if the language for the value of the
given property is known and matches the language name given in the
<literal> element, FALSE if it doesn't match and UNKNOWN if the
property itself is not defined.
Languages are considered to match if they are the same, or if the
language of the property value is a sublanguage of the language
specified in the <literal> element (see [XPATH], section 4.3, "lang
function").
5.12.3 Example of language-aware matching
The expression below will evaluate to TRUE if the property "foobar"
exists and it's language is either unknown, English or a sublanguage
of English.
<or xmlns="DAV:">
<not>
<language-defined>
<prop><foobar/></prop>
</language-defined>
</not>
<language-matches>
<prop><foobar/></prop>
<literal>en</literal>
</language-matches>
</or>
5.13 DAV:is-collection
The DAV:is-collection operator allows clients to determine whether a
resource is a collection (that is, whether it's DAV:resourcetype
element contains the element DAV:collection).
Rationale: This operator is provided in lieu of defining generic
structure queries, which would suffice for this and for many more
powerful queries, but seems inappropriate to standardize at this
time.
5.13.1 Example of DAV:is-collection
This example shows a search criterion that picks out all and only the
resources in the scope that are collections.
Reschke, et al. Expires August 6, 2004 [Page 31]
Internet-Draft WebDAV SEARCH February 2004
<where xmlns="DAV:">
<is-collection/>
</where>
5.14 DAV:is-defined
The DAV:is-defined operator allows clients to determine whether a
property is defined on a resource. The meaning of "defined on a
resource" is found in Section 5.5.3.
Example:
<d:is-defined>
<d:prop><x:someprop/></d:prop>
</d:is-defined>
5.15 DAV:like
The DAV:like is an optional operator intended to give simple
wildcard-based pattern matching ability to clients.
The operator takes two arguments.
The first argument is a DAV:prop element identifying a single
property to evaluate.
The second argument is a DAV:literal element that gives the pattern
matching string.
5.15.1 Syntax for the Literal Pattern
Pattern := [wildcard] 0*( text [wildcard] )
wildcard := exactlyone | zeroormore
text := 1*( <character> | escapesequence )
exactlyone : = "_"
zeroormore := "%"
escapechar := "\"
escapesequence := "\" ( exactlyone | zeroormore | escapechar )
character: valid XML characters (see section 2.2 of [XML]),
minus ( exactlyone | zeroormore | escapechar )
The value for the literal is composed of wildcards separated by
segments of text. Wildcards may begin or end the literal.
The "_" wildcard matches exactly one character.
The "%" wildcard matches zero or more characters
Reschke, et al. Expires August 6, 2004 [Page 32]
Internet-Draft WebDAV SEARCH February 2004
The "\" character is an escape sequence so that the literal can
include >"_" and "%". To include the "\" character in the pattern,
the escape sequence "\\" is used.
5.15.2 Example of DAV:like
This example shows how a client might use DAV:like to identify those
resources whose content type was a subtype of image.
<D:where>
<D:like caseless="yes">
<D:prop><D:getcontenttype/></D:prop>
<D:literal>image/%</D:literal>
</D:like>
</D:where>
5.16 DAV:contains
The DAV:contains operator is an optional operator that provides
content-based search capability. This operator implicitly searches
against the text content of a resource, not against content of
properties. The DAV:contains operator is intentionally not overly
constrained, in order to allow the server to do the best job it can
in performing the search.
The DAV:contains operator evaluates to a Boolean value. It evaluates
to TRUE if the content of the resource satisfies the search.
Otherwise, It evaluates to FALSE.
Within the DAV:contains XML element, the client provides a phrase: a
single word or whitespace delimited sequence of words. Servers MAY
ignore punctuation in a phrase. Case-sensitivity is left to the
server.
The following things may or may not be done as part of the search:
Phonetic methods such as "soundex" may or may not be used. Word
stemming may or may not be performed. Thesaurus expansion of words
may or may not be done. Right or left truncation may or may not be
performed. The search may be case insensitive or case sensitive. The
word or words may or may not be interpreted as names. Multiple words
may or may not be required to be adjacent or "near" each other.
Multiple words may or may not be required to occur in the same order.
Multiple words may or may not be treated as a phrase. The search may
or may not be interpreted as a request to find documents "similar" to
the string operand.
Reschke, et al. Expires August 6, 2004 [Page 33]
Internet-Draft WebDAV SEARCH February 2004
5.16.1 Result scoring (DAV:score element)
Servers SHOULD indicate scores for the DAV:contains condition by
adding a DAV:score XML element to the DAV:response element. It's
value is defined only in the context of a particular query result.
The value is a string representing the score, an integer from zero to
10000 inclusive, where a higher value indicates a higher score (e.g.
more relevant).
Modified DTD fragment for DAV:propstat:
<!ELEMENT response (href, ((href*, status)|(propstat+)),
responsedescription?, score?) >
<!ELEMENT score (#PCDATA) >
Clients should note that, in general, it is not meaningful to compare
the numeric values of scores from two different query results unless
both were executed by the same underlying search system on the same
collection of resources.
5.16.2 Ordering by score
To order search results by their score, the DAV:score element may be
added as child to the DAV:orderby element (in place of a DAV:prop
element).
5.16.3 Examples
The example below shows a search for the phrase "Peter Forsberg".
Depending on its support for content-based searching, a server MAY
treat this as a search for documents that contain the words "Peter"
and "Forsberg".
<D:where>
<D:contains>Peter Forsberg</D:contains>
</D:where>
The example below shows a search for resources that contain "Peter"
and "Forsberg".
<D:where>
<D:and>
<D:contains>Peter</D:contains>
<D:contains>Forsberg</D:contains>
</D:and>
</D:where>
Reschke, et al. Expires August 6, 2004 [Page 34]
Internet-Draft WebDAV SEARCH February 2004
5.17 Limiting the result set
<!ELEMENT limit (nresults) >
<!ELEMENT nresults (#PCDATA)> ;only digits
The DAV:limit XML element contains requested limits from the client
to limit the size of the reply or amount of effort expended by the
server. The DAV:nresults XML element contains a requested maximum
number of DAV:response elements to be returned in the response body.
The server MAY disregard this limit. The value of this element is an
integer.
5.17.1 Relationship to result ordering
If the result set is both limited by DAV:limit and ordered according
to DAV:orderby, the results that are included in the response
document must be those that order highest.
5.18 The 'caseless' XML attribute
The "caseless" attribute allows clients to specify caseless matching
behaviour instead of character-by-character matching for
DAV:basicsearch operators.
The possible values for "caseless" are "yes" or "no". The default
value is server-specified. Caseless matching SHOULD be implemented as
defined in section 5.18 of the Unicode Standard ([UNICODE4]).
Support for the "caseless" attribute is optional. A server should
respond with a status of 422 if it is used but cannot be supported.
5.19 Query schema for DAV:basicsearch
The DAV:basicsearch grammar defines a search criteria that is a
Boolean-valued expression, and allows for an arbitrary set of
properties to be included in the result record. The result set may be
sorted on a set of property values. Accordingly the DTD for schema
discovery for this grammar allows the server to express:
1. the set of properties that may be either searched, returned, or
used to sort, and a hint about the data type of such properties
2. the set of optional operators defined by the resource.
Reschke, et al. Expires August 6, 2004 [Page 35]
Internet-Draft WebDAV SEARCH February 2004
5.19.1 DTD for DAV:basicsearch QSD
<!ELEMENT basicsearchschema (properties, operators)>
<!ELEMENT any-other-property EMPTY>
<!ELEMENT properties (propdesc*)>
<!ELEMENT propdesc (prop|any-other-property), datatype?,
searchable?, selectable?, sortable?,
caseless?)>
<!ELEMENT operators (opdesc*)>
<!ELEMENT opdesc ANY>
<!ELEMENT operand-literal EMPTY>
<!ELEMENT operand-property EMPTY>
The DAV:properties element holds a list of descriptions of
properties.
The DAV:operators element describes the optional operators that may
be used in a DAV:where element.
5.19.2 DAV:propdesc Element
Each instance of a DAV:propdesc element describes the property or
properties in the DAV:prop element it contains. All subsequent
elements are descriptions that apply to those properties. All
descriptions are optional and may appear in any order. Servers SHOULD
support all the descriptions defined here, and MAY define others.
DASL defines five descriptions. The first, DAV:datatype, provides a
hint about the type of the property value, and may be useful to a
user interface prompting for a value. The remaining four
(DAV:searchable, DAV:selectable, DAV:sortable, and DAV:caseless)
identify portions of the query (DAV:where, DAV:select, and
DAV:orderby, respectively). If a property has a description for a
section, then the server MUST allow the property to be used in that
section. These descriptions are optional. If a property does not have
such a description, or is not described at all, then the server MAY
still allow the property to be used in the corresponding section.
5.19.2.1 DAV:any-other-property
This element can be used in place of DAV:prop to describe properties
of WebDAV properties not mentioned in any other DAV:prop element. For
instance, this can be used to indicate that all other properties are
searchable and selectable without giving details about their types (a
typical scenario for dead properties).
Reschke, et al. Expires August 6, 2004 [Page 36]
Internet-Draft WebDAV SEARCH February 2004
5.19.3 The DAV:datatype Property Description
The DAV:datatype element contains a single XML element that provides
a hint about the domain of the property, which may be useful to a
user interface prompting for a value to be used in a query. Datatypes
are identified by an element name. Where appropriate, a server SHOULD
use the simple datatypes defined in [XS2].
<!ELEMENT datatype ANY >
Examples from [XS2], section 3:
+----------------+---------------------+
| Qualified name | Example |
+----------------+---------------------+
| xs:boolean | true, false, 1, 0 |
| | |
| xs:string | Foobar |
| | |
| xs:dateTime | 1994-11-05T08:15:5Z |
| | |
| xs:float | .314159265358979E+1 |
| | |
| xs:integer | -259, 23 |
+----------------+---------------------+
If the data type of a property is not given, then the data type
defaults to xs:string.
5.19.4 The DAV:searchable Property Description
<!ELEMENT searchable EMPTY>
If this element is present, then the server MUST allow this property
to appear within a DAV:where element where an operator allows a
property. Allowing a search does not mean that the property is
guaranteed to be defined on every resource in the scope, it only
indicates the server's willingness to check.
5.19.5 The DAV:selectable Property Description
<!ELEMENT selectable EMPTY>
This element indicates that the property may appear in the DAV:select
element.
Reschke, et al. Expires August 6, 2004 [Page 37]
Internet-Draft WebDAV SEARCH February 2004
5.19.6 The DAV:sortable Property Description
This element indicates that the property may appear in the
DAV:orderby element.
<!ELEMENT sortable EMPTY>
5.19.7 The DAV:caseless Property Description
This element only applies to properties whose data type is
"xs:string" and derived data types as per the DAV:datatype property
description. Its presence indicates that compares performed for
searches, and the comparisons for ordering results on the string
property will be caseless (the default is character-by-character).
<!ELEMENT caseless EMPTY>
5.19.8 The DAV:operators XML Element
The DAV:operators element describes every optional operator supported
in a query. (Mandatory operators are not listed since they are
mandatory and permit no variation in syntax.). All optional operators
that are supported MUST be listed in the DAV:operators element. The
listing for an operator consists of the operator (as an empty
element), followed by one element for each operand. The operand MUST
be either DAV:operand-property or DAV:operand-literal, which indicate
that the operand in the corresponding position is a property or a
literal value, respectively. If an operator is polymorphic (allows
more than one operand syntax) then each permitted syntax MUST be
listed separately.
<operators xmlns='DAV:'>
<opdesc>
<like/><operand-property/><operand-literal/>
</opdesc>
</operators>
Reschke, et al. Expires August 6, 2004 [Page 38]
Internet-Draft WebDAV SEARCH February 2004
5.19.9 Example of Query Schema for DAV:basicsearch
<D:basicsearchschema xmlns:D="DAV:"
xmlns:xs="http://www.w3.org/2001/XMLSchema"">
<D:properties>
<D:propdesc>
<D:prop><D:getcontentlength/></D:prop>
<D:datatype><xs:nonNegativeInteger/></D:datatype>
<D:searchable/><D:selectable/><D:sortable/>
</D:propdesc>
<D:propdesc>
<D:prop><D:getcontenttype/><D:displayname/></D:prop>
<D:searchable/><D:selectable/><D:sortable/>
</D:propdesc>
<D:propdesc>
<D:prop><fstop xmlns="http://jennicam.org"/></D:prop>
<D:selectable/>
</D:propdesc>
<D:propdesc>
<D:any-other-property/>
<D:searchable/><D:selectable/>
</D:propdesc>
</D:properties>
<D:operators>
<D:opdesc>
<D:like/><D:operand-property/><D:operand-literal/>
</D:opdesc>
</D:operators>
</D:basicsearchschema>
This response lists four properties. The datatype of the last three
properties is not given, so it defaults to xs:string. All are
selectable, and the first three may be searched. All but the last may
be used in a sort. Of the optional DAV operators, DAV:is-defined and
DAV:like are supported.
Note: The schema discovery defined here does not provide for
discovery of supported values of the "caseless" attribute. This may
require that the reply also list the mandatory operators.
Reschke, et al. Expires August 6, 2004 [Page 39]
Internet-Draft WebDAV SEARCH February 2004
6. Internationalization Considerations
Properties may be language-tagged using the xml:lang attribute (see
[RFC2518], section 4.4). The optional operators DAV:language-defined
(Section 5.12.1) and DAV:language-matches (Section 5.12.2) allow to
express conditions on the language tagging information.
Reschke, et al. Expires August 6, 2004 [Page 40]
Internet-Draft WebDAV SEARCH February 2004
7. Security Considerations
This section is provided to detail issues concerning security
implications of which DASL applications need to be aware. All of the
security considerations of HTTP/1.1 also apply to DASL. In addition,
this section will include security risks inherent in searching and
retrieval of resource properties and content.
A query must not allow one to retrieve information about values or
existence of properties that one could not obtain via PROPFIND. (e.g.
by use in DAV:orderby, or in expressions on properties.)
A server should prepare for denial of service attacks. For example a
client may issue a query for which the result set is expensive to
calculate or transmit because many resources match or must be
evaluated.
7.1 Implications of XML External Entities
XML supports a facility known as "external entities", defined in
section 4.2.2 of [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
[XML]. However, [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 [RFC3023]. 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.
Reschke, et al. Expires August 6, 2004 [Page 41]
Internet-Draft WebDAV SEARCH February 2004
8. Scalability
Query grammars are identified by URIs. Applications SHOULD not
attempt to retrieve these URIs even if they appear to be retrievable
(for example, those that begin with "http://")
Reschke, et al. Expires August 6, 2004 [Page 42]
Internet-Draft WebDAV SEARCH February 2004
9. Authentication
Authentication mechanisms defined in WebDAV will also apply to DASL.
Reschke, et al. Expires August 6, 2004 [Page 43]
Internet-Draft WebDAV SEARCH February 2004
10. IANA Considerations
This document uses the namespace defined by [RFC2518] for XML
elements. All other IANA considerations mentioned in [RFC2518] are
also applicable to DASL.
Reschke, et al. Expires August 6, 2004 [Page 44]
Internet-Draft WebDAV SEARCH February 2004
11. Contributors
This document is based on prior work on the DASL protocol done by the
WebDAV DASL working group until the year 2000 -- namely by Alan
Babich, Jim Davis, Rick Henderson, Dale Lowry, Saveen Reddy and
Surendra Reddy.
Reschke, et al. Expires August 6, 2004 [Page 45]
Internet-Draft WebDAV SEARCH February 2004
12. Acknowledgements
This document has benefited from thoughtful discussion by Lisa
Dusseault, Sung Kim, Elias Sinderson, Martin Wallmer, Jim Whitehead
and Kevin Wiggen.
Reschke, et al. Expires August 6, 2004 [Page 46]
Internet-Draft WebDAV SEARCH February 2004
Normative References
[ACL] Clemm, G., Hopkins, A., Sedlar, E. and J. Whitehead,
"WebDAV Access Control Protocol", ID
draft-ietf-webdav-acl-13, January 2004, <http://
www.webdav.org/acl/protocol/draft-ietf-webdav-acl-13.htm>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2518] Goland, Y., Whitehead, E., Faizi, A., Carter, S. and D.
Jensen, "HTTP Extensions for Distributed Authoring --
WEBDAV", RFC 2518, February 1999.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Nielsen, H.,
Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC3023] Makoto, M., St.Laurent, S. and D. Kohn, "XML Media Types",
RFC 3023, January 2001.
[RFC3253] Clemm, G., Amsden, J., Ellison, T., Kaler, C. and J.
Whitehead, "Versioning Extensions to WebDAV", RFC 3253,
March 2002.
[XML] Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, E. and
F. Yergeau, "Extensible Markup Language (XML) 1.0 (Third
Edition)", W3C REC-xml-20040204, February 2004, <http://
www.w3.org/TR/2004/REC-xml-20040204>.
[XMLNS] Bray, T., Hollander, D. and A. Layman, "Namespaces in
XML", W3C REC-xml-names-19990114, January 1999, <http://
www.w3.org/TR/1999/REC-xml-names-19990114>.
[XPATH] Clark, J. and S. DeRose, "XML Path Language (XPath)
Version 1.0", W3C REC REC-xpath-19991116, November 1999,
<http://www.w3.org/TR/1999/REC-xpath-19991116>.
[XS1] Thompson, H., Beech, D., Maloney, M., Mendelsohn, N. and
World Wide Web Consortium, "XML Schema Part 1:
Structures", W3C REC-xmlschema-1-20010502, May 2001,
<http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/>.
[XS2] Biron, P., Malhotra, A. and World Wide Web Consortium,
"XML Schema Part 2: Datatypes", W3C
REC-xmlschema-2-20010502, May 2001, <http://www.w3.org/TR/
2001/REC-xmlschema-2-20010502/>.
Reschke, et al. Expires August 6, 2004 [Page 47]
Internet-Draft WebDAV SEARCH February 2004
Informative References
[BIND] Clemm, G., Crawford, J., Reschke, J., Slein, J. and J.
Whitehead, "Binding Extensions to WebDAV", ID
draft-ietf-webdav-bind-03, December 2003, <http://
greenbytes.de/tech/webdav/draft-ietf-webdav-bind-03.html>.
[DASL] Reddy, S., Lowry, D., Reddy, S., Henderson, R., Davis, J.
and A. Babich, "DAV Searching & Locating", ID
draft-dasl-protocol-00, July 1999, <http://www.webdav.org/
dasl/protocol/draft-dasl-protocol-00.html>.
[DASLREQ] Davis, J., Reddy, S. and J. Slein, "Requirements for DAV
Searching and Locating", ID draft-dasl-requirements-01,
February 1999, <http://www.webdav.org/dasl/requirements/
draft-dasl-requirements-01.html>.
[SQL99] Milton, J., "Database Language SQL Part 2: Foundation
(SQL/Foundation)", ISO ISO/IEC 9075-2:1999 (E), July 1999.
[UNICODE4]
The Unicode Consortium, "The Unicode Standard - Version
4.0", Addison-Wesley , August 2003, <http://
www.unicode.org/versions/Unicode4.0.0/>.
ISBN 0321185781 [3]
Reschke, et al. Expires August 6, 2004 [Page 48]
Internet-Draft WebDAV SEARCH February 2004
URIs
[1] <mailto:www-webdav-dasl@w3.org>
[2] <mailto:www-webdav-dasl-request@w3.org?subject=subscribe>
[3] <urn:isbn:0321185781>
Authors' Addresses
Julian F. Reschke (editor)
greenbytes GmbH
Salzmannstrasse 152
Muenster, NW 48159
Germany
Phone: +49 251 2807760
Fax: +49 251 2807761
EMail: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/
Surendra Reddy
Oracle Corporation
600 Oracle Parkway, M/S 6op3
Redwoodshores, CA 94065
Phone: +1 650 506 5441
EMail: Surendra.Reddy@oracle.com
Jim Davis
Intelligent Markets
410 Jessie Street 6th floor
San Francisco, CA 94103
EMail: jrd3@alum.mit.edu
Alan Babich
FileNET Corp.
3565 Harbor Blvd.
Costa Mesa, CA 92626
Phone: +1 714 327 3403
EMail: ababich@filenet.com
Reschke, et al. Expires August 6, 2004 [Page 49]
Internet-Draft WebDAV SEARCH February 2004
Appendix A. Three-Valued Logic in DAV:basicsearch
ANSI standard three valued logic is used when evaluating the search
condition (as defined in the ANSI standard SQL specifications, for
example in ANSI X3.135-1992, section 8.12, pp. 188-189, section 8.2,
p. 169, General Rule 1)a), etc.).
ANSI standard three valued logic is undoubtedly the most widely
practiced method of dealing with the issues of properties in the
search condition not having a value (e.g., being null or not defined)
for the resource under scan, and with undefined expressions in the
search condition (e.g., division by zero, etc.). Three valued logic
works as follows.
Undefined expressions are expressions for which the value of the
expression is not defined. Undefined expressions are a completely
separate concept from the truth value UNKNOWN, which is, in fact,
well defined. Property names and literal constants are considered
expressions for purposes of this section. If a property in the
current resource under scan has not been set to a value, then the
value of that property is undefined for the resource under scan. DASL
1.0 has no arithmetic division operator, but if it did, division by
zero would be an undefined arithmetic expression.
If any subpart of an arithmetic, string, or datetime subexpression is
undefined, the whole arithmetic, string, or datetime subexpression is
undefined.
There are no manifest constants to explicitly represent undefined
number, string, or datetime values.
Since a Boolean value is ultimately returned by the search condition,
arithmetic, string, and datetime expressions are always arguments to
other operators. Examples of operators that convert arithmetic,
string, and datetime expressions to Boolean values are the six
relational operators ("greater than", "less than", "equals", etc.).
If either or both operands of a relational operator have undefined
values, then the relational operator evaluates to UNKNOWN. Otherwise,
the relational operator evaluates to TRUE or FALSE, depending upon
the outcome of the comparison.
The Boolean operators DAV:and, DAV:or and DAV:not are evaluated
according to the following rules:
UNKNOWN and UNKNOWN = UNKNOWN
UNKNOWN or UNKNOWN = UNKNOWN
Reschke, et al. Expires August 6, 2004 [Page 50]
Internet-Draft WebDAV SEARCH February 2004
not UNKNOWN = UNKNOWN
UNKNOWN and TRUE = UNKNOWN
UNKNOWN and FALSE = FALSE
UNKNOWN and UNKNOWN = UNKNOWN
UNKNOWN or TRUE = TRUE
UNKNOWN or FALSE = UNKNOWN
UNKNOWN or UNKNOWN = UNKNOWN
Reschke, et al. Expires August 6, 2004 [Page 51]
Internet-Draft WebDAV SEARCH February 2004
Appendix B. Change Log (to be removed by RFC Editor before publication)
B.1 From draft-davis-dasl-protocol-xxx
Feb 14, 1998 Initial Draft
Feb 28, 1998 Referring to DASL as an extension to HTTP/1.1 rather
than DAV.
Added new sections "Notational Conventions", "Protocol Model",
"Security Considerations".
Changed section 3 to "Elements of Protocol".
Added some stuff to introduction.
Added "result set" terminology.
Added "IANA Considerations".
Mar 9, 1998 Moved sub-headings of "Elements of Protocol" to first
level and removed "Elements of Protocol" Heading.
Added an sentence in introduction explaining that this is a
"sketch" of a protocol.
Mar 11, 1998 Added orderby, data typing, three valued logic, query
schema property, and element definitions for schema for
basicsearch.
April 8, 1998 - made changes based on last week's DASL BOF.
May 8, 1998 Removed most of DAV:searcherror; converted to
DAV:searchredirect
Altered DAV:basicsearch grammar to use avoid use of ANY in DTD
June 17, 1998 -Added details on Query Schema Discovery
-Shortened list of data types
June 23, 1998 moved data types before change history
rewrote the data types section
removed the casesensitive element and replace with the
casesensitive attribute
added the casesensitive attribute to the DTD for all operations
that might work on a string
Jul 20, 1998 A series of changes. See Author's meeting minutes for
details.
July 28, 1998 Changes as per author's meeting. QSD uses SEARCH, not
PROPFIND.
Moved text around to keep concepts nearby.
Boolean literals are 1 and 0, not T and F.
contains changed to contentspassthrough.
Reschke, et al. Expires August 6, 2004 [Page 52]
Internet-Draft WebDAV SEARCH February 2004
Renamed rank to score.
July 28, 1998 Added Dale Lowry as Author
September 4, 1998 Added 422 as response when query lists
unimplemented operators.
DAV:literal declares a default value for xml:space, 'preserve'
(see XML spec, section 2.10)
moved to new XML namespace syntax
September 22, 1998 Changed "simplesearch" to "basicsearch"
Changed isnull to isdefined
Defined NULLness as having a 404 or 403 response
used ENTITY syntax in DTD
Added redirect
October 9, 1998 Fixed a series of typographical and formatting
errors.
Modified the section of three-valued logic to use a table rather
than a text description of the role of UNKNOWN in expressions.
November 2, 1998 Added the DAV:contains operator.
Removed the DAV:contentpassthrough operator.
November 18, 1998 Various author comments for submission
June 3, 1999 Cosmetic and minor editorial changes only. Fix nits
reported by Jim Whitehead in email of April 26, 1999. Converted to
HTML from Word 97, manually.
April 20, 2000 Removed redirection feature, since 301/302 suffices.
Removed Query Schema Discovery (former chapter 4). Everyone agrees
this is a useful feature, but it is apparently too difficult to
define at this time, and it is not essential for DASL.
B.2 since start of draft-reschke-webdav-search
October 09, 2001 Added Julian Reschke as author.
Chapter about QSD re-added.
Formatted into RFC2629-compliant XML document.
Added first comments.
ID version number kicked up to draft-dasl-protocol-03.
October 17, 2001 Updated address information for Jim Davis.
Added issue of datatype vocabularies.
Updated issue descriptions for grammar discovery, added issues on
query schema DTD.
Reschke, et al. Expires August 6, 2004 [Page 53]
Internet-Draft WebDAV SEARCH February 2004
Fixed typos in XML examples.
December 17, 2001 Re-introduced split between normative and
non-normative references.
January 05, 2002 Version bumbed up to 04. Started work on resolving
the issues identified in the previous version.
January 14, 2002 Fixed some XML typos.
January 22, 2002 Closed issues naming-of-elements. Fixed query search
DTD and added option to discover properties of "other"
(non-listed) properties.
January 25, 2002 Changed into private submission and added reference
to historic DASL draft. Marked reference to DASL requirements
non-normative.
Updated reference to latest deltav spec.
January 29, 2002 Added feedback from and updated contact info for
Alan Babich.
Included open issues collected in http://www.webdav.org/dasl/
protocol/issues.html.
February 8, 2002 Made sure that all artwork fits into 72 characters
wide text.
February 18, 2002 Changed Insufficient storage handling
(multistatus). Moved is-collection to operators and added to DTD.
Made scope/depth mandatory.
February 20, 2002 Updated reference to SQL99.
February 28, 2002 "Non-normative References" -> "Informative
References". Abstract updated. Consistently specify a charset when
using text/xml (no change bars). Do not attempt to define
PROPFIND's entity encoding (take out specific references to text/
xml). Remove irrelevant headers (Connection:) from examples (no
change bars). Added issue on querying based on DAV:href. Updated
introduction to indicate relationship to DASL draft. Updated HTTP
reference from RFC2068 to RFC2616. Updated XML reference to XML
1.0 2nd edition.
March 1, 2002 Removed superfluous namespace decl in 2.4.2. Reopened
JW14 and suggest to drop xml:space support.
Reschke, et al. Expires August 6, 2004 [Page 54]
Internet-Draft WebDAV SEARCH February 2004
March 3, 2002 Removed "xml:space" feature on DAV:literal. Added issue
about string comparison vs. collations vs. xml:lang. Updated some
of the open issues with details from JimW's original mail in April
1999. Resolved scope vs relative URI references. Resolved issues
about DAV:ascending (added to index) and the BNF for DAV:like
(changed "octets" to "characters").
March 8, 2002 Updated reference to DeltaV (now RFC3253). Added Martin
Wallmer's comments, moved JW5 into DAV:basicsearch section.
March 11, 2002 Closed open issues regaring the type of search
arbiters (JW3) and their discovery (JW9). Rephrased requirements
on multistatus response bodies (propstat only if properties were
selected, removed requirement for responsedescription).
March 23, 2002 RFC2376 -> RFC3023. Added missing first names of
authors. OPTIONS added to example for DAV:supported-method-set.
B.3 since draft-reschke-webdav-search-00
March 29, 2002 Abstract doesn't refer to DASL WG anymore.
April 7, 2002 Fixed section title (wrong property name
supported-search-grammar-set. Changed DAV:casesensitve to
"casesensitive" (it wasn't in the DAV: namespace after all).
May 28, 2002 Updated some issues with Jim Davis's comments.
June 10, 2002 Added proposal for different method for query schema
discovery, not using pseudo-properties.
June 25, 2002 QSD marshalling rewritten. Added issue
"isdefined-optional".
B.4 since draft-reschke-webdav-search-01
July 04, 2002 Added issue "scope-collection".
July 08, 2002 Closed issue "scope-collection".
August 12, 2002 Added issues "results-vs-binds" and "select-allprop".
October 22, 2002 Added issue "undefined-expressions".
Reschke, et al. Expires August 6, 2004 [Page 55]
Internet-Draft WebDAV SEARCH February 2004
November 18, 2002 Changed example host names (no change tracking).
November 25, 2002 Updated issue "DB2/DB7". Closed issues "undefined
expressions", "isdefined-optional" and "select-allprop".
B.5 since draft-reschke-webdav-search-02
November 27, 2002 Added issues "undefined-properties",
"like-exactlyone" and "like-wildcard-adjacent". Closed issue
"query-on-href". Added acknowledgments section.
November 28, 2002 Closed issue "like-exactlyone". Added issue
"mixed-content-properties".
December 14, 2002 Closed issues "undefined-properties",
"results-vs-binds", "mixed-content-properties". Updated issue
"like-wildcard-adjacent". Added informative reference to BIND
draft. Updated reference to ACL draft.
January 9, 2003 Removed duplicate section on invalid scopes. Added
comments to some open issues. Closed issues JW25/26,
score-pseudo-property and null-ordering.
January 10, 2003 Issue limit-vs-ordering plus resolution. Closed
issue JW17/JW24b.
January 14, 2003 New issue order-precedence. Started resolution of
DB2/DB7.
January 15, 2003 Started spec of DAV:typed-literal.
January 17, 2003 Fix one DAV:like/DAV:getcontenttype example (add /
to like expression, make case-insensitive).
January 28, 2003 Update issue(s) result-truncation, JW24d. Fixed
response headers in OPTIONS example. Added issue qsd-optional.
Closed issue(s) order-precedence, case-insensitivity-name.
February 07, 2003 Added issue scope-vs-versions.
score-pseudo-property: allow DAV:orderby to explicitly specify
DAV:score.
B.6 since draft-reschke-webdav-search-03
Reschke, et al. Expires August 6, 2004 [Page 56]
Internet-Draft WebDAV SEARCH February 2004
April 24, 2003 Fixed two "?" vs "_" issues (not updated in last
draft).
June 13, 2003 Improve index.
B.7 since draft-reschke-webdav-search-04
July 7, 2003 Typo fixed (propstat without status element).
August 11, 2003 Remove superfluous IP and copyright sections.
September 09, 2003 Added issues "2.4-multiple-uris" and
"5.1-name-filtering".
October 06, 2003 Fix misplaced section end in 5.11, add table
formatting. Enhance table formatting in 5.18.3. Updated ACL and
BIND references. Added XPATH reference. Closed issue JW24d by
adding new optional operators. Updated more open issues, added
issues from January meeting. Add K. Wiggen to Acknowledgements.
Add Contributors section for the authors of the original draft.
Close issue "scope-vs-versions" (optional feature added). Close
(new) issue "1.3-import-DTD-terminology". Add issue
"1.3-import-requirements-terminology".
October 07, 2003 Typos fixed. Moved statement about DAV: namespace
usage into separate (sub-)section. Closed
"1.3-import-requirements-terminology". Update I18N Considerations
with new xml:lang support info (see issue JW24d). Close issue
"DB2/DB7" (remaining typing issues are now summarized in issue
"typed-literal"). Fix misplaced section end in section 7. Started
change to use RFC3253-style method definitions and error
marshalling.
October 08, 2003 Remove obsolete language that allowed reporting
invalid scopes and such inside multistatus. Add new issue
"5.4.2-scope-vs-redirects".
B.8 since draft-reschke-webdav-search-05
October 11, 2003 Separate DAV:basicsearch DTD into separate figures
for better maintainability. Update DTD with language-* operators
and typed-literal element (optional).
October 14, 2003 Close issue "5.4.2-multiple-scope".
Reschke, et al. Expires August 6, 2004 [Page 57]
Internet-Draft WebDAV SEARCH February 2004
November 04, 2003 Update reference from CaseMap to UNICODE4, section
5.18.
November 16, 2003 Updated issue "5.1-name-filtering".
November 24, 2003 Reformatted scope description (collection vs.
non-collection).
November 30, 2003 Add issue "5_media_type_match".
February 6, 2004 Updated all references.
Reschke, et al. Expires August 6, 2004 [Page 58]
Internet-Draft WebDAV SEARCH February 2004
Appendix C. Resolved issues (to be removed by RFC Editor before
publication)
Issues that were either rejected or resolved in this version of this
document.
C.1 5.4.2-multiple-scope
Type: change
<http://lists.w3.org/Archives/Public/www-webdav-dasl/2003JulSep/
0012.html>
prakash.yamuna@covigna.com (2003-09-27): (asks for the ability to
specify multiple scopes in a single query)
julian.reschke@greenbytes.de (2003-10-03): Consider making this an
optional extension iff we can come up with a simple enough definition
of it's impact on sorting/ranking and so on. Otherwise propose to
reject.
Resolution (2003-10-14): Allow servers to support multiple scopes in
DAV:basicsearch. Make clear that this is optional. Define
precondition accordingly.
Reschke, et al. Expires August 6, 2004 [Page 59]
Internet-Draft WebDAV SEARCH February 2004
Appendix D. Open issues (to be removed by RFC Editor prior to
publication)
D.1 1.3-apply-condition-code-terminology
Type: change
julian.reschke@greenbytes.de (2003-10-07): (Umbrella issue that will
be left open until RFC3253 condition terminlogy is used throughout
the document)
D.2 2.4-multiple-uris
Type: change
julian.reschke@greenbytes.de (2003-09-09): However, the set of URIs
for a given resource may be unlimited due to possible bind loops.
Therefore consider to report just one URI per resource.
D.3 result-truncation
Type: change
<http://lists.w3.org/Archives/Public/www-webdav-dasl/2002JanMar/
0163.html>
ldusseault@xythos.com (2002-03-29): I believe the same response body
that contains the first N <DAV:response> elements should also contain
a *different* element stating that the results were incomplete and
the result set was truncated by the server. There may also be a need
to report that the results were incomplete and the result set was
truncated at the choice of the client (isn't there a limit set in the
client request?) That's important so the client knows the difference
between receiving 10 results because there were >10 but only 10 were
asked for, and receiving 10 results because there were only exactly
10 results and it just happens that 10 were asked for.
jrd3@alum.mit.edu (2002-05-28): I agree that this could be useful,
but I think this issue should be consolidated with issue JW5 (see
below), which proposes that DASL basicsearch ought to have a way for
client to request additional result sets. It should be moved because
there is little or no value in allowing a client to distinguish
between the case where "N results were requested, and there are
exactly N available" and "N results were requested, and there are
more than N available" if there is no way for client to get the next
batch of results.
julian.reschke@greenbytes.de (2003-01-28): Feedback from interim WG
Reschke, et al. Expires August 6, 2004 [Page 60]
Internet-Draft WebDAV SEARCH February 2004
meeting: agreement that marshalling should be rewritten and backwards
compatibility is not important. Proposal: extend DAV:multistatus by a
new child element that indicates (1) the range that was returned, (2)
the total number of results and (3) a URI identifying the result (for
resubmission when getting the "next" results). Such as <multistatus
xmlns='DAV:'> <search-result> <href>...identifier for result set...</
href> <total><-- number of results --></total> <start><-- 1-based
index of 1st result --></start> <length><-- size of result set
returned --></length> <partial-result/><-- indicates that this is a
partial result --> </search-result> ...response elements for search
results... </multistatus> The example below would then translate to:
HTTP/1.1 207 Multistatus Content-Type: text/xml; charset="utf-8"
Content-Length: xxx <?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:"> <D:search-result> <D:partial-result/>
</D:search-result> <D:response> <D:href>http://www.example.net/
sounds/unbrokenchain.au</D:href> <D:propstat> <D:prop/>
<D:status>HTTP/1.1 200 OK</D:status> </D:propstat> </D:response>
<D:response> <D:href>http://tech.mit.test/archive96/photos/
Lesh1.jpg</D:href> <D:propstat> <D:prop/> <D:status>HTTP/1.1 200 OK</
D:status> </D:propstat> </D:response> </D:multistatus> Q: do we need
all elements, in particular start and length?
julian.reschke@greenbytes.de (2003-10-07): Related: if this is
supposed to be normative to DAV:basicsearch, it can't stay in an
"example" sub-section.
D.4 qsd-optional
Type: change
julian.reschke@greenbytes.de (2003-01-28): WG January meeting
feedback: QSD should be made required.
kwiggen@xythos.com (2003-10-03): (significant pushback, see mailing
list thread at http://lists.w3.org/Archives/Public/www-webdav-dasl/
2003OctDec/0003.html).
D.5 5.1-name-filtering
Type: change
<http://lists.w3.org/Archives/Public/www-webdav-dasl/2003JulSep/
0002.html>
julian.reschke@greenbytes.de (2003-09-08): This query grammar
supports properties and content, but not conditions on URL elements
(such as the last segment that many WebDAV implementations treat as
"file name"). Discuss possible extension such as adding name filters
Reschke, et al. Expires August 6, 2004 [Page 61]
Internet-Draft WebDAV SEARCH February 2004
to the scope, or adding a specific operator.
Martin.Wallmer@softwareag.com (2003-11-11): Specific proposal to add
this feature as scope restriction, see <http://lists.w3.org/Archives/
Public/www-webdav-dasl/2003OctDec/0035.html>.
Martin.Wallmer@softwareag.com (2003-11-25): Updated proposal: <http:/
/lists.w3.org/Archives/Public/www-webdav-dasl/2003OctDec/0100.html>.
D.6 5_media_type_match
Type: change
julian.reschke@greenbytes.de (2003-11-30): Putting conditions on
DAV:getcontenttype is hard (see <http://lists.w3.org/Archives/Public/
www-webdav-dasl/2003OctDec/0101.html> is (too?) hard. Proposal for a
specific operator for expressing conditions on the media type:
<http://lists.w3.org/Archives/Public/www-webdav-dasl/2003OctDec/
0109.html>.
D.7 5.4.2-scope-vs-redirects
Type: change
<http://lists.w3.org/Archives/Public/www-webdav-dasl/2003OctDec/
0010.html>
julian.reschke@greenbytes.de (2003-10-08): Clarify the relation of
scope and redirect (3xx) resources.
D.8 language-comparison
Type: change
<http://lists.w3.org/Archives/Public/www-webdav-dasl/2002JanMar/
0122.html>
julian.reschke@greenbytes.de (2002-03-03): XPath/XQuery (see draft,
and open issue) specify string comparisons based on collations, not
languages. I think we should adopt this. This would mean that
"xml:lang" would be removed, and an optional attribute specifying the
name of the collation is added.
julian.reschke@greenbytes.de (2003-01-09): Proposal: adopt "lang" and
"collation" attribute from XSLT 2.0's xsl:sort.
Reschke, et al. Expires August 6, 2004 [Page 62]
Internet-Draft WebDAV SEARCH February 2004
D.9 JW16b/JW24a
Type: change
<http://lists.w3.org/Archives/Public/www-webdav-dasl/1999AprJun/
0002.html>
ejw@ics.uci.edu (2000-04-20): Define how comparisons on strings work,
esp for i18n. Need policy statement about sort order in various
national languages. (JW said "non-Latin" but it's an issue even in
languages that use the latin char set.)
julian.reschke@greenbytes.de (2003-01-28): This issue not only
applies to the comparison operators, but also to ordering!
D.10 typed-literal
Type: change
julian.reschke@greenbytes.de (2003-01-15): 1. (insert language
defining the comparison following the rules defined in http://
www.w3.org/TR/xpath20/#id-comparisons). 2. Extend Basicsearch QSD
grammar to support discovery of typed-literal 3. Update DTD. 4.
Discuss behaviour of DAV:literal when the property's type is known
for the complete search scope (is the server allowed to be "smart"?)
julian.reschke@greenbytes.de (2003-10-11): 3.: done
Reschke, et al. Expires August 6, 2004 [Page 63]
Internet-Draft WebDAV SEARCH February 2004
Index
C
caseless attribute 28, 35
Condition Names
DAV:search-grammar-discovery-supported (pre) 10
DAV:search-grammar-supported (pre) 10
DAV:search-multiple-scope-supported (pre) 10
DAV:search-scope-valid (pre) 10
Criteria 5
D
DAV:and 28
DAV:ascending 27
DAV:contains 33
DAV:depth 24
DAV:descending 27
DAV:eq 28
caseless attribute 28
DAV:from 24
DAV:gt 29
DAV:gte 29
DAV:include-versions 24
DAV:is-collection 31
DAV:is-defined 32
DAV:language-defined 30
DAV:language-matches 31
DAV:like 32
DAV:limit 35
DAV:literal 29
DAV:lt 29
DAV:lte 29
DAV:not 28
DAV:nresults 35
DAV:or 28
DAV:orderby 27
DAV:scope 24
DAV:score 34
relationship to DAV:orderby 35
DAV:search-grammar-discovery-supported precondition 10
DAV:search-grammar-supported precondition 10
DAV:search-multiple-scope-supported precondition 10
DAV:search-scope-valid precondition 10
DAV:select 24
DAV:supported-query-grammar-set property 16
DAV:typed-literal 29
DAV:where 25
Reschke, et al. Expires August 6, 2004 [Page 64]
Internet-Draft WebDAV SEARCH February 2004
M
Methods
SEARCH 9
O
OPTIONS method 15
DASL response header 15
P
Properties
DAV:supported-query-grammar-set 16
Q
Query Grammar Discovery 15
using live property 16
using OPTIONS 15
Query Grammar 6
Query Schema 6
Query 5
R
Result Record Definition 6
Result Record 6
Result Set Truncation
Example 12
Result Set 6
Result 6
S
Scope 6
SEARCH method 9
Search Modifier 6
Sort Specification 6
Reschke, et al. Expires August 6, 2004 [Page 65]
Internet-Draft WebDAV SEARCH February 2004
Intellectual Property Statement
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 of the 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.
Full Copyright Statement
Copyright (C) The Internet Society (2004). All Rights Reserved.
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
Reschke, et al. Expires August 6, 2004 [Page 66]
Internet-Draft WebDAV SEARCH February 2004
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgment
Funding for the RFC Editor function is currently provided by the
Internet Society.
Reschke, et al. Expires August 6, 2004 [Page 67]
