idnits 2.17.1
draft-reschke-webdav-search-05.txt:
Checking boilerplate required by RFC 5378 and the IETF Trust (see
https://trustee.ietf.org/license-info):
----------------------------------------------------------------------------
** Looks like you're using RFC 2026 boilerplate. This must be updated to
follow RFC 3978/3979, as updated by RFC 4748.
Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt:
----------------------------------------------------------------------------
== No 'Intended status' indicated for this document; assuming Proposed
Standard
Checking nits according to https://www.ietf.org/id-info/checklist :
----------------------------------------------------------------------------
** The abstract seems to contain references ([2], [1]), which it shouldn't.
Please replace those with straight textual mentions of the documents in
question.
== There are 1 instance of lines with non-RFC2606-compliant FQDNs in the
document.
Miscellaneous warnings:
----------------------------------------------------------------------------
== The copyright year in the RFC 3978 Section 5.4 Copyright Line does not
match the current year
== Line 987 has weird spacing: '...ment is is an...'
== The document seems to lack the recommended RFC 2119 boilerplate, even if
it appears to use RFC 2119 keywords -- however, there's a paragraph with
a matching beginning. Boilerplate error?
(The document does seem to have the reference to RFC 2119 which the
ID-Checklist requires).
== Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD',
or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please
use uppercase 'NOT' together with RFC 2119 keywords (if that is what you
mean).
Found 'SHOULD not' in this paragraph:
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://")
-- The document seems to lack a disclaimer for pre-RFC5378 work, but may
have content which was first submitted before 10 November 2008. If you
have contacted all the original authors and they are all willing to grant
the BCP78 rights to the IETF Trust, then this is fine, and you can ignore
this comment. If not, you may need to add the pre-RFC5378 disclaimer.
(See the Legal Provisions document at
https://trustee.ietf.org/license-info for more information.)
-- The document date (October 10, 2003) is 7503 days in the past. Is this
intentional?
Checking references for intended status: Proposed Standard
----------------------------------------------------------------------------
(See RFCs 3967 and 4897 for information about using normative references
to lower-maturity documents in RFCs)
== Unused Reference: 'XMLNS' is defined on line 1756, but no explicit
reference was found in the text
== Outdated reference: A later version (-13) exists of
draft-ietf-webdav-acl-12
** Obsolete normative reference: RFC 2518 (Obsoleted by RFC 4918)
** Obsolete normative reference: RFC 2616 (Obsoleted by RFC 7230, RFC 7231,
RFC 7232, RFC 7233, RFC 7234, RFC 7235)
** Obsolete normative reference: RFC 3023 (Obsoleted by RFC 7303)
-- Possible downref: Non-RFC (?) normative reference: ref. 'XML'
-- Possible downref: Non-RFC (?) normative reference: ref. 'XMLNS'
-- Possible downref: Non-RFC (?) normative reference: ref. 'XPATH'
-- Possible downref: Non-RFC (?) normative reference: ref. 'XS1'
-- Possible downref: Non-RFC (?) normative reference: ref. 'XS2'
== Outdated reference: A later version (-27) exists of
draft-ietf-webdav-bind-02
-- No information found for draft-dasl-protocol - is the name correct?
-- No information found for draft-dasl-requirements - is the name correct?
Summary: 5 errors (**), 0 flaws (~~), 9 warnings (==), 9 comments (--).
Run idnits with the --verbose option for more detailed information about
the items above.
--------------------------------------------------------------------------------
2 Network Working Group J. Reschke, Ed.
3 Internet-Draft greenbytes
4 Expires: April 9, 2004 S. Reddy
5 Oracle
6 J. Davis
7 Intelligent Markets
8 A. Babich
9 Filenet
10 October 10, 2003
12 WebDAV SEARCH
13 draft-reschke-webdav-search-05
15 Status of this Memo
17 This document is an Internet-Draft and is in full conformance with
18 all provisions of Section 10 of RFC2026.
20 Internet-Drafts are working documents of the Internet Engineering
21 Task Force (IETF), its areas, and its working groups. Note that other
22 groups may also distribute working documents as Internet-Drafts.
24 Internet-Drafts are draft documents valid for a maximum of six months
25 and may be updated, replaced, or obsoleted by other documents at any
26 time. It is inappropriate to use Internet-Drafts as reference
27 material or to cite them other than as "work in progress."
29 The list of current Internet-Drafts can be accessed at http://
30 www.ietf.org/ietf/1id-abstracts.txt.
32 The list of Internet-Draft Shadow Directories can be accessed at
33 http://www.ietf.org/shadow.html.
35 This Internet-Draft will expire on April 9, 2004.
37 Copyright Notice
39 Copyright (C) The Internet Society (2003). All Rights Reserved.
41 Abstract
43 This document specifies a set of methods, headers, properties and
44 content-types composing WebDAV SEARCH, an application of the HTTP/1.1
45 protocol to efficiently search for DAV resources based upon a set of
46 client-supplied criteria.
48 Distribution of this document is unlimited. Please send comments to
49 the Distributed Authoring and Versioning (WebDAV) DASL mailing list
50 at www-webdav-dasl@w3.org [1], which may be joined by sending a
51 message with subject "subscribe" to www-webdav-dasl-request@w3.org
52 [2]. Discussions of the WebDAV DASL mailing list are archived at URL:
53 http://www.w3.org/pub/WWW/Archives/Public/www-webdav-dasl/.
55 Table of Contents
57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 5
58 1.1 DASL . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
59 1.2 Relationship to DAV . . . . . . . . . . . . . . . . . . . 5
60 1.3 Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 5
61 1.4 Notational Conventions . . . . . . . . . . . . . . . . . . 7
62 1.5 Editorial note on usage of 'DAV:' namespace . . . . . . . 7
63 1.6 An Overview of DASL at Work . . . . . . . . . . . . . . . 8
64 2. The SEARCH Method . . . . . . . . . . . . . . . . . . . . 9
65 2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . 9
66 2.2 The Request . . . . . . . . . . . . . . . . . . . . . . . 9
67 2.2.1 The Request-URI . . . . . . . . . . . . . . . . . . . . . 9
68 2.2.2 The Request Body . . . . . . . . . . . . . . . . . . . . . 9
69 2.3 The Successful 207 (Multistatus) Response . . . . . . . . 10
70 2.3.1 Extending the PROPFIND Response . . . . . . . . . . . . . 10
71 2.3.2 Example: A Simple Request and Response . . . . . . . . . . 10
72 2.3.3 Example: Result Set Truncation . . . . . . . . . . . . . . 11
73 2.4 Unsuccessful Responses . . . . . . . . . . . . . . . . . . 13
74 2.4.1 Example of an Invalid Scope . . . . . . . . . . . . . . . 13
75 3. Discovery of Supported Query Grammars . . . . . . . . . . 14
76 3.1 The OPTIONS Method . . . . . . . . . . . . . . . . . . . . 14
77 3.2 The DASL Response Header . . . . . . . . . . . . . . . . . 14
78 3.3 DAV:supported-query-grammar-set (protected) . . . . . . . 15
79 3.4 Example: Grammar Discovery . . . . . . . . . . . . . . . . 15
80 4. Query Schema Discovery: QSD . . . . . . . . . . . . . . . 18
81 4.1 Additional SEARCH semantics . . . . . . . . . . . . . . . 18
82 4.1.1 Example of query schema discovery . . . . . . . . . . . . 19
83 5. The DAV:basicsearch Grammar . . . . . . . . . . . . . . . 21
84 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 21
85 5.2 The DAV:basicsearch DTD . . . . . . . . . . . . . . . . . 21
86 5.2.1 Example Query . . . . . . . . . . . . . . . . . . . . . . 22
87 5.3 DAV:select . . . . . . . . . . . . . . . . . . . . . . . . 23
88 5.4 DAV:from . . . . . . . . . . . . . . . . . . . . . . . . . 23
89 5.4.1 Relationship to the Request-URI . . . . . . . . . . . . . 24
90 5.4.2 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 24
91 5.5 DAV:where . . . . . . . . . . . . . . . . . . . . . . . . 24
92 5.5.1 Use of Three-Valued Logic in Queries . . . . . . . . . . . 24
93 5.5.2 Handling Optional operators . . . . . . . . . . . . . . . 24
94 5.5.3 Treatment of NULL Values . . . . . . . . . . . . . . . . . 24
95 5.5.4 Treatment of properties with mixed/element content . . . . 25
96 5.5.5 Example: Testing for Equality . . . . . . . . . . . . . . 25
97 5.5.6 Example: Relative Comparisons . . . . . . . . . . . . . . 25
98 5.6 DAV:orderby . . . . . . . . . . . . . . . . . . . . . . . 26
99 5.6.1 Comparing Natural Language Strings . . . . . . . . . . . . 26
100 5.6.2 Example of Sorting . . . . . . . . . . . . . . . . . . . . 26
101 5.7 Boolean Operators: DAV:and, DAV:or, and DAV:not . . . . . 27
102 5.8 DAV:eq . . . . . . . . . . . . . . . . . . . . . . . . . . 27
103 5.9 DAV:lt, DAV:lte, DAV:gt, DAV:gte . . . . . . . . . . . . . 27
104 5.10 DAV:literal . . . . . . . . . . . . . . . . . . . . . . . 27
105 5.11 DAV:typed-literal (optional) . . . . . . . . . . . . . . . 28
106 5.11.1 Example for typed numerical comparison . . . . . . . . . . 28
107 5.12 Support for matching xml:lang attributes on properties . . 29
108 5.12.1 DAV:language-defined (optional) . . . . . . . . . . . . . 29
109 5.12.2 DAV:language-matches (optional) . . . . . . . . . . . . . 29
110 5.12.3 Example of language-aware matching . . . . . . . . . . . . 29
111 5.13 DAV:is-collection . . . . . . . . . . . . . . . . . . . . 30
112 5.13.1 Example of DAV:is-collection . . . . . . . . . . . . . . . 30
113 5.14 DAV:is-defined . . . . . . . . . . . . . . . . . . . . . . 30
114 5.15 DAV:like . . . . . . . . . . . . . . . . . . . . . . . . . 30
115 5.15.1 Syntax for the Literal Pattern . . . . . . . . . . . . . . 31
116 5.15.2 Example of DAV:like . . . . . . . . . . . . . . . . . . . 31
117 5.16 DAV:contains . . . . . . . . . . . . . . . . . . . . . . . 31
118 5.16.1 Result scoring (DAV:score element) . . . . . . . . . . . . 32
119 5.16.2 Ordering by score . . . . . . . . . . . . . . . . . . . . 32
120 5.16.3 Examples . . . . . . . . . . . . . . . . . . . . . . . . . 32
121 5.17 Limiting the result set . . . . . . . . . . . . . . . . . 33
122 5.17.1 Relationship to result ordering . . . . . . . . . . . . . 33
123 5.18 The 'caseless' XML attribute . . . . . . . . . . . . . . . 33
124 5.19 Query schema for DAV:basicsearch . . . . . . . . . . . . . 34
125 5.19.1 DTD for DAV:basicsearch QSD . . . . . . . . . . . . . . . 34
126 5.19.2 DAV:propdesc Element . . . . . . . . . . . . . . . . . . . 34
127 5.19.3 The DAV:datatype Property Description . . . . . . . . . . 35
128 5.19.4 The DAV:searchable Property Description . . . . . . . . . 35
129 5.19.5 The DAV:selectable Property Description . . . . . . . . . 36
130 5.19.6 The DAV:sortable Property Description . . . . . . . . . . 36
131 5.19.7 The DAV:caseless Property Description . . . . . . . . . . 36
132 5.19.8 The DAV:operators XML Element . . . . . . . . . . . . . . 36
133 5.19.9 Example of Query Schema for DAV:basicsearch . . . . . . . 37
134 6. Internationalization Considerations . . . . . . . . . . . 38
135 7. Security Considerations . . . . . . . . . . . . . . . . . 39
136 7.1 Implications of XML External Entities . . . . . . . . . . 39
137 8. Scalability . . . . . . . . . . . . . . . . . . . . . . . 40
138 9. Authentication . . . . . . . . . . . . . . . . . . . . . . 41
139 10. IANA Considerations . . . . . . . . . . . . . . . . . . . 42
140 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . 43
141 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . 44
142 Normative References . . . . . . . . . . . . . . . . . . . 45
143 Informative References . . . . . . . . . . . . . . . . . . 46
144 Authors' Addresses . . . . . . . . . . . . . . . . . . . . 47
145 A. Three-Valued Logic in DAV:basicsearch . . . . . . . . . . 48
146 B. Change Log (to be removed by RFC Editor before
147 publication) . . . . . . . . . . . . . . . . . . . . . . . 50
148 B.1 From draft-davis-dasl-protocol-xxx . . . . . . . . . . . . 50
149 B.2 since start of draft-reschke-webdav-search . . . . . . . . 51
150 B.3 since draft-reschke-webdav-search-00 . . . . . . . . . . . 53
151 B.4 since draft-reschke-webdav-search-01 . . . . . . . . . . . 53
152 B.5 since draft-reschke-webdav-search-02 . . . . . . . . . . . 54
153 B.6 since draft-reschke-webdav-search-03 . . . . . . . . . . . 54
154 B.7 since draft-reschke-webdav-search-04 . . . . . . . . . . . 55
155 C. Resolved issues (to be removed by RFC Editor before
156 publication) . . . . . . . . . . . . . . . . . . . . . . . 56
157 C.1 1.3-import-condition-code-terminology . . . . . . . . . . 56
158 C.2 1.3-import-requirements-terminology . . . . . . . . . . . 56
159 C.3 1.3-import-DTD-terminology . . . . . . . . . . . . . . . . 56
160 C.4 invalid-scope . . . . . . . . . . . . . . . . . . . . . . 56
161 C.5 JW24d . . . . . . . . . . . . . . . . . . . . . . . . . . 57
162 C.6 scope-vs-versions . . . . . . . . . . . . . . . . . . . . 58
163 C.7 DB2/DB7 . . . . . . . . . . . . . . . . . . . . . . . . . 58
164 D. Open issues (to be removed by RFC Editor before
165 publication) . . . . . . . . . . . . . . . . . . . . . . . 61
166 D.1 1.3-apply-condition-code-terminology . . . . . . . . . . . 61
167 D.2 2.4-multiple-uris . . . . . . . . . . . . . . . . . . . . 61
168 D.3 result-truncation . . . . . . . . . . . . . . . . . . . . 61
169 D.4 qsd-optional . . . . . . . . . . . . . . . . . . . . . . . 62
170 D.5 5.1-name-filtering . . . . . . . . . . . . . . . . . . . . 62
171 D.6 5.4.2-multiple-scope . . . . . . . . . . . . . . . . . . . 63
172 D.7 5.4.2-scope-vs-redirects . . . . . . . . . . . . . . . . . 63
173 D.8 language-comparison . . . . . . . . . . . . . . . . . . . 63
174 D.9 JW16b/JW24a . . . . . . . . . . . . . . . . . . . . . . . 63
175 D.10 typed-literal . . . . . . . . . . . . . . . . . . . . . . 64
176 Index . . . . . . . . . . . . . . . . . . . . . . . . . . 65
177 Intellectual Property and Copyright Statements . . . . . . 67
179 1. Introduction
181 1.1 DASL
183 This document defines WebDAV SEARCH, an application of HTTP/1.1
184 forming a lightweight search protocol to transport queries and result
185 sets and allows clients to make use of server-side search facilities.
186 It is based on the expired draft for WebDAV DASL [DASL]. [DASLREQ]
187 describes the motivation for DASL.
189 DASL will minimize the complexity of clients so as to facilitate
190 widespread deployment of applications capable of utilizing the DASL
191 search mechanisms.
193 DASL consists of:
195 o the SEARCH method,
197 o the DASL response header,
199 o the DAV:searchrequest XML element,
201 o the DAV:query-schema-discovery XML element,
203 o the DAV:basicsearch XML element and query grammar, and
205 o the DAV:basicsearchschema XML element.
207 For WebDAV-compliant servers, it also defines a new live property
208 DAV:supported-query-grammar-set.
210 1.2 Relationship to DAV
212 DASL relies on the resource and property model defined by [RFC2518].
213 DASL does not alter this model. Instead, DASL allows clients to
214 access DAV-modeled resources through server-side search.
216 1.3 Terms
218 This document uses the terms defined in [RFC2616], in [RFC2518], in
219 [RFC3253] and in this section.
221 Criteria
223 An expression against which each resource in the search scope is
224 evaluated.
226 Query
227 A query is a combination of a search scope, search criteria,
228 result record definition, sort specification, and a search
229 modifier.
231 Query Grammar
233 A set of definitions of XML elements, attributes, and constraints
234 on their relations and values that defines a set of queries and
235 the intended semantics.
237 Query Schema
239 A listing, for any given grammar and scope, of the properties and
240 operators that may be used in a query with that grammar and scope.
242 Result
244 A result is a result set, optionally augmented with other
245 information describing the search as a whole.
247 Result Record
249 A description of a resource. A result record is a set of
250 properties, and possibly other descriptive information.
252 Result Record Definition
254 A specification of the set of properties to be returned in the
255 result record.
257 Result Set
259 A set of records, one for each resource for which the search
260 criteria evaluated to True.
262 Scope
264 A set of resources to be searched.
266 Search Modifier
268 An instruction that governs the execution of the query but is not
269 part of the search scope, result record definition, the search
270 criteria, or the sort specification. An example of a search
271 modifier is one that controls how much time the server can spend
272 on the query before giving a response.
274 Sort Specification
275 A specification of an ordering on the result records in the result
276 set.
278 1.4 Notational Conventions
280 The augmented BNF used by this document to describe protocol elements
281 is exactly the same as the one described in Section 2.1 of [RFC2616].
282 Because this augmented BNF uses the basic production rules provided
283 in Section 2.2 of [RFC2616], those rules apply to this document as
284 well.
286 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT"
287 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
288 document are to be interpreted as described in [RFC2119].
290 This document uses XML DTD fragments as a purely notational
291 convention. WebDAV request and response bodies can not be validated
292 due to the specific extensibility rules defined in section 23 of
293 [RFC2518] and due to the fact that all XML elements defined by this
294 specification use the XML namespace name "DAV:". In particular:
296 1. element names use the "DAV:" namespace,
298 2. element ordering is irrelevant unless explicitly stated,
300 3. extension elements (elements not already defined as valid child
301 elements) may be added anywhere, except when explicitly stated
302 otherwise,
304 4. extension attributes (attributes not already defined as valid for
305 this element) may be added anywhere, except when explicitly
306 stated otherwise.
308 When an XML element type in the "DAV:" namespace is referenced in
309 this document outside of the context of an XML fragment, the string
310 "DAV:" will be prefixed to the element type.
312 Similarily, when an XML element type in the namespace "http://
313 www.w3.org/2001/XMLSchema" is referenced in this document outside of
314 the context of an XML fragment, the string "xs:" will be prefixed to
315 the element type.
317 1.5 Editorial note on usage of 'DAV:' namespace
319 *Note that this draft currently defines elements and properties in
320 the WebDAV namespace "DAV:" which it shouldn't do as it isn't a work
321 item of the WebDAV working group. The reason for this is the desire
322 for some kind of backward compatibility to the expired DASL drafts
323 and the assumption that the draft may become an official RFC
324 submission of the WebDAV working group at a later point of time.*
326 1.6 An Overview of DASL at Work
328 One can express the basic usage of DASL in the following steps:
330 o The client constructs a query using the DAV:basicsearch grammar.
332 o The client invokes the SEARCH method on a resource that will
333 perform the search (the search arbiter) and includes a text/xml or
334 application/xml request entity that contains the query.
336 o The search arbiter performs the query.
338 o The search arbiter sends the results of the query back to the
339 client in the response. The server MUST send an entity that
340 matches the [RFC2518] PROPFIND response.
342 2. The SEARCH Method
344 2.1 Overview
346 The client invokes the SEARCH method to initiate a server-side
347 search. The body of the request defines the query. The server MUST
348 emit an entity matching the [RFC2518] PROPFIND response.
350 The SEARCH method plays the role of transport mechanism for the query
351 and the result set. It does not define the semantics of the query.
352 The type of the query defines the semantics.
354 2.2 The Request
356 The client invokes the SEARCH method on the resource named by the
357 Request-URI.
359 2.2.1 The Request-URI
361 The Request-URI identifies the search arbiter. Any HTTP resource may
362 function as search arbiter. It is not a new type of resource (in the
363 sense of DAV:resourcetype as defined in [RFC2518]), nor does it have
364 to be a WebDAV-compliant resource.
366 The SEARCH method defines no relationship between the arbiter and the
367 scope of the search, rather the particular query grammar used in the
368 query defines the relationship. For example, a query grammar may
369 force the request-URI to correspond exactly to the search scope.
371 2.2.2 The Request Body
373 The server MUST process a text/xml or application/xml request body,
374 and MAY process request bodies in other formats. See [RFC3023] for
375 guidance on packaging XML in requests.
377 Marshalling:
379 If a request body with content type text/xml or application/xml is
380 included, it MUST be either a DAV:searchrequest or a
381 DAV:query-schema-discovery XML element. It's single child element
382 identifies the query grammar.
384 For DAV:searchrequest, the definition of search criteria, the
385 result record, and any other details needed to perform the search
386 depend on the individual search grammar.
388 For DAV:query-schema-discovery, the semantics is defined in
389 Section 4.
391 Preconditions:
393 (DAV:search-grammar-discovery-supported): when an XML request body
394 is present and has a DAV:query-schema-discovery document element,
395 the server MUST support the query schema discovery mechanism
396 described in Section 4.
398 (DAV:search-grammar-supported): when an XML request body is
399 present, the search grammar identified by the document element's
400 child element must be a supported search grammar.
402 (DAV:search-scope-valid): the supplied search scope must be valid.
403 There can be various reasons for a search scope to be invalid,
404 including unsupported URI schemes and communication problems.
405 Servers MAY add [RFC2518] compliant DAV:response elements as
406 content to the condition element indicating the precise reason for
407 the failure.
409 2.3 The Successful 207 (Multistatus) Response
411 If the server returns 207 (Multistatus), then the search proceeded
412 successfully and the response MUST match that of a PROPFIND. The
413 results of this method SHOULD NOT be cached.
415 There MUST be one DAV:response for each resource that matched the
416 search criteria. For each such response, the DAV:href element
417 contains the URI of the resource, and the response MUST include a
418 DAV:propstat element.
420 Note that for each matching resource found there may be multiple URIs
421 within the search scope mapped to it. In this case, a server SHOULD
422 report all of these URIs. Clients can use the live property
423 DAV:resource-id defined in [BIND] to identify possible duplicates.
425 2.3.1 Extending the PROPFIND Response
427 A response MAY include more information than PROPFIND defines so long
428 as the extra information does not invalidate the PROPFIND response.
429 Query grammars SHOULD define how the response matches the PROPFIND
430 response.
432 2.3.2 Example: A Simple Request and Response
434 This example demonstrates the request and response framework. The
435 following XML document shows a simple (hypothetical) natural language
436 query. The name of the query element is natural-language-query in the
437 XML namespace "http://example.com/foo". The actual query is "Find the
438 locations of good Thai restaurants in Los Angeles". For this
439 hypothetical query, the arbiter returns two properties for each
440 selected resource.
442 >> Request:
444 SEARCH / HTTP/1.1
445 Host: example.org
446 Content-Type: application/xml
447 Content-Length: xxx
449
450
451
452 Find the locations of good Thai restaurants in Los Angeles
453
454
456 >> Response:
458 HTTP/1.1 207 Multi-Status
459 Content-Type: text/xml; charset="utf-8"
460 Content-Length: xxx
462
463
465
466 http://siamiam.test/
467
468
469 259 W. Hollywood
470 4
471
472 HTTP/1.1 200 OK
473
474
475
477 2.3.3 Example: Result Set Truncation
479 A server MAY limit the number of resources in a reply, for example to
480 limit the amount of resources expended in processing a query. If it
481 does so, the reply MUST use status code 207, return a DAV:multistatus
482 response body and indicate a status of 507 (Insufficient Storage) for
483 the search arbiter URI. It SHOULD include the partial results.
485 When a result set is truncated, there may be many more resources that
486 satisfy the search criteria but that were not examined.
488 If partial results are included and the client requested an ordered
489 result set in the original request, then any partial results that are
490 returned MUST be ordered as the client directed.
492 Note that the partial results returned MAY be any subset of the
493 result set that would have satisfied the original query.
495 >> Request:
497 SEARCH / HTTP/1.1
498 Host: example.net
499 Content-Type: text/xml; charset="utf-8"
500 Content-Length: xxx
502 ... the query goes here ...
504 >> Response:
506 HTTP/1.1 207 Multistatus
507 Content-Type: text/xml; charset="utf-8"
508 Content-Length: xxx
510
511
512
513 http://www.example.net/sounds/unbrokenchain.au
514
515
516 HTTP/1.1 200 OK
517
518
519
520 http://tech.mit.test/archive96/photos/Lesh1.jpg
521
522
523 HTTP/1.1 200 OK
524
525
526
527 http://example.net
528 HTTP/1.1 507 Insufficient Storage
529
530 Only first two matching records were returned
531
532
534
536 2.4 Unsuccessful Responses
538 If a SEARCH request could not be executed or the attempt to execute
539 it resulted in an error, the server MUST indicate the failure with an
540 appropriate status code and SHOULD add a response body as defined in
541 [RFC3253], section 1.6. Unless otherwise stated, condition elements
542 are empty, however specific conditions element MAY include additional
543 child elements that describe the error condition in more detail.
545 2.4.1 Example of an Invalid Scope
547 In the example below, a request failed because the scope identifies a
548 HTTP resource that was not found.
550 >> Response:
552 HTTP/1.1 409 Conflict
553 Content-Type: text/xml; charset="utf-8"
554 Content-Length: xxx
556
557
558
559
560 http://www.example.com/X
561 HTTP/1.1 404 Object Not Found
562
563
564
566 3. Discovery of Supported Query Grammars
568 Servers MUST support discovery of the query grammars supported by a
569 search arbiter resource.
571 Clients can determine which query grammars are supported by an
572 arbiter by invoking OPTIONS on the search arbiter. If the resource
573 supports SEARCH, then the DASL response header will appear in the
574 response. The DASL response header lists the supported grammars.
576 Servers supporting the WebDAV extensions [RFC3253] and/or [ACL] MUST
577 also
579 o report SEARCH in the live property DAV:supported-method-set for
580 all search arbiter resources and
582 o support the live property DAV:supported-query-grammar-set as
583 defined in Section 3.3.
585 3.1 The OPTIONS Method
587 The OPTIONS method allows the client to discover if a resource
588 supports the SEARCH method and to determine the list of search
589 grammars supported for that resource.
591 The client issues the OPTIONS method against a resource named by the
592 Request-URI. This is a normal invocation of OPTIONS defined in
593 [RFC2616].
595 If a resource supports the SEARCH method, then the server MUST list
596 SEARCH in the OPTIONS response as defined by [RFC2616].
598 DASL servers MUST include the DASL header in the OPTIONS response.
599 This header identifies the search grammars supported by that
600 resource.
602 3.2 The DASL Response Header
604 DASLHeader = "DASL" ":" Coded-URL-List
605 Coded-URL-List : Coded-URL [ "," Coded-URL-List ]
606 Coded-URL ; defined in section 9.4 of [RFC2518]
608 The DASL response header indicates server support for a query grammar
609 in the OPTIONS method. The value is a URI that indicates the type of
610 grammar. Note that although the URI can be used to identify each
611 supported search grammar, there is not necessarily a direct
612 relationship between the URI and the XML element name that can be
613 used in XML based SEARCH requests (the element name itself is
614 identified by it's namespace name (a URI reference) and the element's
615 local name).
617 This header MAY be repeated.
619 For example:
621 DASL:
622 DASL:
623 DASL:
624 DASL:
626 3.3 DAV:supported-query-grammar-set (protected)
628 This WebDAV property is required for any server supporting either
629 [RFC3253] and/or [ACL] and identifies the XML based query grammars
630 that are supported by the search arbiter resource.
632
633
634
636 ANY value: a query grammar element type
638 3.4 Example: Grammar Discovery
640 This example shows that the server supports search on the /somefolder
641 resource with the query grammars: DAV:basicsearch, http://
642 foobar.test/syntax1 and http://akuma.test/syntax2. Note that every
643 server MUST support DAV:basicsearch.
645 >> Request:
647 OPTIONS /somefolder HTTP/1.1
648 Host: example.org
650 >> Response:
652 HTTP/1.1 200 OK
653 Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE
654 Allow: MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, SEARCH
655 DASL:
656 DASL:
657 DASL:
659 This example shows the equivalent taking advantage of a server's
660 support for DAV:supported-method-set and
661 DAV:supported-query-grammar-set.
663 >> Request:
665 PROPFIND /somefolder HTTP/1.1
666 Host: example.org
667 Depth: 0
668 Content-Type: text/xml; charset="utf-8"
669 Content-Length: xxx
671
672
673
674
675
676
677
679 >> Response:
681 HTTP/1.1 207 Multi-Status
682 Content-Type: text/xml; charset="utf-8"
683 Content-Length: xxx
685
686
687
688 http://example.org/somefolder
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720 HTTP/1.1 200 OK
721
722
723
725 Note that the query grammar element names marshalled as part of the
726 DAV:supported-query-grammar-set can be directly used as element names
727 in an XML based query.
729 4. Query Schema Discovery: QSD
731 Servers MAY support the discovery of the schema for a query grammar.
733 The DASL response header and the DAV:supported-query-grammar-set
734 property provide means for clients to discover the set of query
735 grammars supported by a resource. This alone is not sufficient
736 information for a client to generate a query. For example, the
737 DAV:basicsearch grammar defines a set of queries consisting of a set
738 of operators applied to a set of properties and values, but the
739 grammar itself does not specify which properties may be used in the
740 query. QSD for the DAV:basicsearch grammar allows a client to
741 discover the set of properties that are searchable, selectable, and
742 sortable. Moreover, although the DAV:basicsearch grammar defines a
743 minimal set of operators, it is possible that a resource might
744 support additional operators in a query. For example, a resource
745 might support a optional operator that can be used to express
746 content-based queries in a proprietary syntax. QSD allows a client to
747 discover these operators and their syntax. The set of discoverable
748 quantities will differ from grammar to grammar, but each grammar can
749 define a means for a client to discover what can be discovered.
751 In general, the schema for a given query grammar depends on both the
752 resource (the arbiter) and the scope. A given resource might have
753 access to one set of properties for one potential scope, and another
754 set for a different scope. For example, consider a server able to
755 search two distinct collections, one holding cooking recipes, the
756 other design documents for nuclear weapons. While both collections
757 might support properties such as author, title, and date, the first
758 might also define properties such as calories and preparation time,
759 while the second defined properties such as yield and applicable
760 patents. Two distinct arbiters indexing the same collection might
761 also have access to different properties. For example, the recipe
762 collection mentioned above might also indexed by a value-added server
763 that also stored the names of chefs who had tested the recipe. Note
764 also that the available query schema might also depend on other
765 factors, such as the identity of the principal conducting the search,
766 but these factors are not exposed in this protocol.
768 4.1 Additional SEARCH semantics
770 Each query grammar supported by DASL defines its own syntax for
771 expressing the possible query schema. A client retrieves the schema
772 for a given query grammar on an arbiter resource with a given scope
773 by invoking the SEARCH method on that arbiter with that grammar and
774 scope and with a root element of DAV:query-schema-discovery rather
775 than DAV:searchrequest.
777 Marshalling:
779 The request body MUST be DAV:query-schema-discovery element.
781
782 ANY value: XML element defining a valid query
784 The response body takes the form of a RFC2518 DAV:multistatus
785 element, where DAV:response is extended to hold the returned query
786 grammar inside a DAV:query-schema container element.
788
790
792 The content of this container is an XML element whose name and syntax
793 depend upon the grammar, and whose value may (and likely will) vary
794 depending upon the grammar, arbiter, and scope.
796 4.1.1 Example of query schema discovery
798 In this example, the arbiter is recipes.test, the grammar is
799 DAV:basicsearch, the scope is also recipes.test.
801 >> Request:
803 SEARCH / HTTP/1.1
804 Host: recipes.test
805 Content-Type: application/xml
806 Content-Length: xxx
808
809
810
811
812
813 http://recipes.test
814 infinity
815
816
817
818
820 >> Response:
822 HTTP/1.1 207 Multistatus
823 Content-Type: application/xml
824 Content-Length: xxx
825
826
827
828 http://recipes.test
829 HTTP/1.1 200 OK
830
831
832
834
835
836
837
839 The query schema for DAV:basicsearch is defined in Section 5.19.
841 5. The DAV:basicsearch Grammar
843 5.1 Introduction
845 DAV:basicsearch uses an extensible XML syntax that allows clients to
846 express search requests that are generally useful for WebDAV
847 scenarios. DASL-extended servers MUST accept this grammar, and MAY
848 accept other grammars.
850 DAV:basicsearch has several components:
852 o DAV:select provides the result record definition.
854 o DAV:from defines the scope.
856 o DAV:where defines the criteria.
858 o DAV:orderby defines the sort order of the result set.
860 o DAV:limit provides constraints on the query as a whole.
862 5.2 The DAV:basicsearch DTD
864
866
868
869
871
872
873
874
875
877
880
882
884
886
887
888
890
891
893
894
896
897
899
900
902
904
906
907
909
911
912
914
915
917
918
920 5.2.1 Example Query
922 This query retrieves the content length values for all resources
923 located under the server's "/container1/" URI namespace whose length
924 exceeds 10000.
926
927
928
929
930
931
932
933 /container1/
934 infinity
935
936
937
938
939
940 10000
941
942
943
944
945
946
947
948
949
950
952 5.3 DAV:select
954 DAV:select defines the result record, which is a set of properties
955 and values. This document defines two possible values: DAV:allprop
956 and DAV:prop, both defined in [RFC2518] and revised in [RFC3253].
958 5.4 DAV:from
960
961
963 DAV:from defines the query scope. This contains exactly one DAV:scope
964 element. The scope element contains mandatory DAV:href and DAV:depth
965 elements.
967 DAV:href indicates the URI to use as a scope.
969 When the scope is a collection, if DAV:depth is "0", the search
970 includes only the collection. When it is "1", the search includes the
971 (toplevel) members of the collection. When it is "infinity", the
972 search includes all recursive members of the collection. When the
973 scope is not a collection, the depth is ignored and the search
974 applies just to the resource itself.
976 When the child element DAV:include-versions is present, the search
977 scope will include all versions (see [RFC3253], section 2.2.1) of all
978 version-controlled resources in scope. Servers that do support
979 versioning but do not support the DAV:include-versions feature MUST
980 signal an error if it is used in a query.
982 5.4.1 Relationship to the Request-URI
984 If the DAV:scope element is an absolute URI, the scope is exactly
985 that URI.
987 If the DAV:scope element is is an absolute URI reference, the scope
988 is taken to be relative to the request-URI.
990 5.4.2 Scope
992 A Scope can be an arbitrary URI.
994 Servers, of course, may support only particular scopes. This may
995 include limitations for particular schemes such as "http:" or "ftp:"
996 or certain URI namespaces.
998 5.5 DAV:where
1000 The DAV:where element defines the search condition for inclusion of
1001 resources in the result set. The value of this element is an XML
1002 element that defines a search operator that evaluates to one of the
1003 Boolean truth values TRUE, FALSE, or UNKNOWN. The search operator
1004 contained by DAV:where may itself contain and evaluate additional
1005 search operators as operands, which in turn may contain and evaluate
1006 additional search operators as operands, etc. recursively.
1008 5.5.1 Use of Three-Valued Logic in Queries
1010 Each operator defined for use in the where clause that returns a
1011 Boolean value MUST evaluate to TRUE, FALSE, or UNKNOWN. The resource
1012 under scan is included as a member of the result set if and only if
1013 the search condition evaluates to TRUE.
1015 Consult Appendix A for details on the application of three-valued
1016 logic in query expressions.
1018 5.5.2 Handling Optional operators
1020 If a query contains an operator that is not supported by the server,
1021 then the server MUST respond with a 422 (Unprocessable Entity) status
1022 code.
1024 5.5.3 Treatment of NULL Values
1026 If a PROPFIND for a property value would yield a non-2xx (see
1027 [RFC2616], section 10.2) response for that property, then that
1028 property is considered NULL.
1030 NULL values are "less than" all other values in comparisons.
1032 Empty strings (zero length strings) are not NULL values. An empty
1033 string is "less than" a string with length greater than zero.
1035 The DAV:is-defined operator is defined to test if the value of a
1036 property is NULL.
1038 5.5.4 Treatment of properties with mixed/element content
1040 Comparisons of properties that do not have simple types (text-only
1041 content) is out-of-scope for the standard operators defined for
1042 DAV:basicsearch and therefore is defined to be UNKNOWN (as per
1043 Appendix A). For querying the DAV:resourcetype property, see Section
1044 5.13.
1046 5.5.5 Example: Testing for Equality
1048 The example shows a single operator (DAV:eq) applied in the criteria.
1050
1051
1052
1053
1054
1055 100
1056
1057
1059 5.5.6 Example: Relative Comparisons
1061 The example shows a more complex operation involving several
1062 operators (DAV:and, DAV:eq, DAV:gt) applied in the criteria. This
1063 DAV:where expression matches those resources that are "image/gifs"
1064 over 4K in size.
1066
1067
1068
1069
1070
1071
1072 image/gif
1073
1074
1075
1076
1077
1078 4096
1079
1080
1081
1083 5.6 DAV:orderby
1085 The DAV:orderby element specifies the ordering of the result set. It
1086 contains one or more DAV:order elements, each of which specifies a
1087 comparison between two items in the result set. Informally, a
1088 comparison specifies a test that determines whether one resource
1089 appears before another in the result set. Comparisons are applied in
1090 the order they occur in the DAV:orderby element, earlier comparisons
1091 being more significant.
1093 The comparisons defined here use only a single property from each
1094 resource, compared using the same ordering as the DAV:lt operator
1095 (ascending) or DAV:gt operator (descending). If neither direction is
1096 specified, the default is DAV:ascending.
1098 In the context of the DAV:orderby element, null values are considered
1099 to collate before any actual (i.e., non null) value, including
1100 strings of zero length (this is compatible with [SQL99]).
1102 5.6.1 Comparing Natural Language Strings
1104 Comparisons on strings take into account the language defined for
1105 that property. Clients MAY specify the language using the xml:lang
1106 attribute. If no language is specified either by the client or
1107 defined for that property by the server or if a comparison is
1108 performed on strings of two different languages, the results are
1109 undefined.
1111 The "caseless" attribute may be used to indicate case-sensitivity for
1112 comparisons.
1114 5.6.2 Example of Sorting
1116 This sort orders first by last name of the author, and then by size,
1117 in descending order, so that for each author, the largest works
1118 appear first.
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1131 5.7 Boolean Operators: DAV:and, DAV:or, and DAV:not
1133 The DAV:and operator performs a logical AND operation on the
1134 expressions it contains.
1136 The DAV:or operator performs a logical OR operation on the values it
1137 contains.
1139 The DAV:not operator performs a logical NOT operation on the values
1140 it contains.
1142 5.8 DAV:eq
1144 The DAV:eq operator provides simple equality matching on property
1145 values.
1147 The "caseless" attribute may be used with this element.
1149 5.9 DAV:lt, DAV:lte, DAV:gt, DAV:gte
1151 The DAV:lt, DAV:lte, DAV:gt, and DAV:gte operators provide
1152 comparisons on property values, using less-than, less-than or equal,
1153 greater-than, and greater-than or equal respectively. The "caseless"
1154 attribute may be used with these elements.
1156 5.10 DAV:literal
1158 DAV:literal allows literal values to be placed in an expression.
1160 White space in literal values is significant in comparisons. For
1161 consistency with [RFC2518], clients SHOULD NOT specify the attribute
1162 "xml:space" (section 2.10 of [XML]) to override this behaviour.
1164 In comparisons, the contents of DAV:literal SHOULD be treated as
1165 string, with the following exceptions:
1167 o when operand for a comparison with a DAV:getcontentlength
1168 property, it SHOULD be treated as an integer value (the behaviour
1169 for non-integer values is undefined),
1171 o when operand for a comparison with a DAV:creationdate or
1172 DAV:getlastmodified property, it SHOULD be treated as a date value
1173 in the ISO-8601 subset defined for the DAV:creationdate property
1174 ([RFC2518], section 13.1).
1176 o when operand for a comparison with a property for which the type
1177 is known, it MAY be treated according to this type.
1179 5.11 DAV:typed-literal (optional)
1181 There are situations in which a client may want to force a comparison
1182 not to be string-based (as defined for DAV:literal). In these cases,
1183 a typed comparison can be enforced by using DAV:typed-literal
1184 instead.
1186
1188 The data type is specified using the xsi:type attribute defined in
1189 [XS1], section 2.6.1. If the type is not specified, it defaults to
1190 "xs:string".
1192 A server MUST reject a request with an unknown type.
1194 5.11.1 Example for typed numerical comparison
1196 Consider a set of resources with the dead property "edits" in the
1197 namespace "http://ns.example.org":
1199 +-----+----------------+
1200 | URI | property value |
1201 +-----+----------------+
1202 | /a | "-1" |
1203 | | |
1204 | /b | "01" |
1205 | | |
1206 | /c | "3" |
1207 | | |
1208 | /d | "test" |
1209 | | |
1210 | /e | (undefined) |
1211 +-----+----------------+
1213 The expression
1215
1218
1219 3
1220
1221 will evaluate to TRUE for the resources "/a" and "/b" (their property
1222 values can be parsed as type xs:number, and the numerical comparison
1223 evaluates to true), to FALSE for "/c" (property value is compatible,
1224 but numerical comparison evaluates to false) and UNKNOWN for "/d" and
1225 "/e" (the property either is undefined, or its value can not be
1226 parsed as xs:number).
1228 5.12 Support for matching xml:lang attributes on properties
1230 The following two optional operators can be used to express
1231 conditions on the language of a property value (as expressed using
1232 the xml:lang attribute).
1234 5.12.1 DAV:language-defined (optional)
1236
1238 This operator evaluates to TRUE if the language for the value of the
1239 given property is known, FALSE if it isn't and UNKNOWN if the
1240 property itself is not defined.
1242 5.12.2 DAV:language-matches (optional)
1244
1246 This operator evaluates to TRUE if the language for the value of the
1247 given property is known and matches the language name given in the
1248 element, FALSE if it doesn't match and UNKNOWN if the
1249 property itself is not defined.
1251 Languages are considered to match if they are the same, or if the
1252 language of the property value is a sublanguage of the language
1253 specified in the element (see [XPATH], section 4.3, "lang
1254 function").
1256 5.12.3 Example of language-aware matching
1258 The expression below will evaluate to TRUE if the property "foobar"
1259 exists and it's language is either unknown, English or a sublanguage
1260 of English.
1262
1263
1264
1265
1266
1267
1268
1269
1270 en
1271
1272
1274 5.13 DAV:is-collection
1276 The DAV:is-collection operator allows clients to determine whether a
1277 resource is a collection (that is, whether it's DAV:resourcetype
1278 element contains the element DAV:collection).
1280 Rationale: This operator is provided in lieu of defining generic
1281 structure queries, which would suffice for this and for many more
1282 powerful queries, but seems inappropriate to standardize at this
1283 time.
1285 5.13.1 Example of DAV:is-collection
1287 This example shows a search criterion that picks out all and only the
1288 resources in the scope that are collections.
1290
1291
1292
1294 5.14 DAV:is-defined
1296 The DAV:is-defined operator allows clients to determine whether a
1297 property is defined on a resource. The meaning of "defined on a
1298 resource" is found in Section 5.5.3.
1300 Example:
1302
1303
1304
1306 5.15 DAV:like
1308 The DAV:like is an optional operator intended to give simple
1309 wildcard-based pattern matching ability to clients.
1311 The operator takes two arguments.
1313 The first argument is a DAV:prop element identifying a single
1314 property to evaluate.
1316 The second argument is a DAV:literal element that gives the pattern
1317 matching string.
1319 5.15.1 Syntax for the Literal Pattern
1321 Pattern := [wildcard] 0*( text [wildcard] )
1322 wildcard := exactlyone | zeroormore
1323 text := 1*( | escapesequence )
1324 exactlyone : = "_"
1325 zeroormore := "%"
1326 escapechar := "\"
1327 escapesequence := "\" ( exactlyone | zeroormore | escapechar )
1328 character: valid XML characters (see section 2.2 of [XML]),
1329 minus ( exactlyone | zeroormore | escapechar )
1331 The value for the literal is composed of wildcards separated by
1332 segments of text. Wildcards may begin or end the literal.
1334 The "_" wildcard matches exactly one character.
1336 The "%" wildcard matches zero or more characters
1338 The "\" character is an escape sequence so that the literal can
1339 include >"_" and "%". To include the "\" character in the pattern,
1340 the escape sequence "\\" is used.
1342 5.15.2 Example of DAV:like
1344 This example shows how a client might use DAV:like to identify those
1345 resources whose content type was a subtype of image.
1347
1348
1349
1350 image/%
1351
1352
1354 5.16 DAV:contains
1356 The DAV:contains operator is an optional operator that provides
1357 content-based search capability. This operator implicitly searches
1358 against the text content of a resource, not against content of
1359 properties. The DAV:contains operator is intentionally not overly
1360 constrained, in order to allow the server to do the best job it can
1361 in performing the search.
1363 The DAV:contains operator evaluates to a Boolean value. It evaluates
1364 to TRUE if the content of the resource satisfies the search.
1365 Otherwise, It evaluates to FALSE.
1367 Within the DAV:contains XML element, the client provides a phrase: a
1368 single word or whitespace delimited sequence of words. Servers MAY
1369 ignore punctuation in a phrase. Case-sensitivity is left to the
1370 server.
1372 The following things may or may not be done as part of the search:
1373 Phonetic methods such as "soundex" may or may not be used. Word
1374 stemming may or may not be performed. Thesaurus expansion of words
1375 may or may not be done. Right or left truncation may or may not be
1376 performed. The search may be case insensitive or case sensitive. The
1377 word or words may or may not be interpreted as names. Multiple words
1378 may or may not be required to be adjacent or "near" each other.
1379 Multiple words may or may not be required to occur in the same order.
1380 Multiple words may or may not be treated as a phrase. The search may
1381 or may not be interpreted as a request to find documents "similar" to
1382 the string operand.
1384 5.16.1 Result scoring (DAV:score element)
1386 Servers SHOULD indicate scores for the DAV:contains condition by
1387 adding a DAV:score XML element to the DAV:response element. It's
1388 value is defined only in the context of a particular query result.
1389 The value is a string representing the score, an integer from zero to
1390 10000 inclusive, where a higher value indicates a higher score (e.g.
1391 more relevant).
1393 Modified DTD fragment for DAV:propstat:
1395
1397
1399 Clients should note that, in general, it is not meaningful to compare
1400 the numeric values of scores from two different query results unless
1401 both were executed by the same underlying search system on the same
1402 collection of resources.
1404 5.16.2 Ordering by score
1406 To order search results by their score, the DAV:score element may be
1407 added as child to the DAV:orderby element (in place of a DAV:prop
1408 element).
1410 5.16.3 Examples
1411 The example below shows a search for the phrase "Peter Forsberg".
1413 Depending on its support for content-based searching, a server MAY
1414 treat this as a search for documents that contain the words "Peter"
1415 and "Forsberg".
1417
1418 Peter Forsberg
1419
1421 The example below shows a search for resources that contain "Peter"
1422 and "Forsberg".
1424
1425
1426 Peter
1427 Forsberg
1428
1429
1431 5.17 Limiting the result set
1433
1434 ;only digits
1436 The DAV:limit XML element contains requested limits from the client
1437 to limit the size of the reply or amount of effort expended by the
1438 server. The DAV:nresults XML element contains a requested maximum
1439 number of DAV:response elements to be returned in the response body.
1440 The server MAY disregard this limit. The value of this element is an
1441 integer.
1443 5.17.1 Relationship to result ordering
1445 If the result set is both limited by DAV:limit and ordered according
1446 to DAV:orderby, the results that are included in the response
1447 document must be those that order highest.
1449 5.18 The 'caseless' XML attribute
1451 The "caseless" attribute allows clients to specify caseless matching
1452 behaviour instead of character-by-character matching for
1453 DAV:basicsearch operators.
1455 The possible values for "caseless" are "yes" or "no". The default
1456 value is server-specified. Caseless matching SHOULD be implemented as
1457 defined in [CaseMap].
1459 Support for the "caseless" attribute is optional. A server should
1460 respond with a status of 422 if it is used but cannot be supported.
1462 5.19 Query schema for DAV:basicsearch
1464 The DAV:basicsearch grammar defines a search criteria that is a
1465 Boolean-valued expression, and allows for an arbitrary set of
1466 properties to be included in the result record. The result set may be
1467 sorted on a set of property values. Accordingly the DTD for schema
1468 discovery for this grammar allows the server to express:
1470 1. the set of properties that may be either searched, returned, or
1471 used to sort, and a hint about the data type of such properties
1473 2. the set of optional operators defined by the resource.
1475 5.19.1 DTD for DAV:basicsearch QSD
1477
1478
1479
1480
1483
1484
1485
1486
1488 The DAV:properties element holds a list of descriptions of
1489 properties.
1491 The DAV:operators element describes the optional operators that may
1492 be used in a DAV:where element.
1494 5.19.2 DAV:propdesc Element
1496 Each instance of a DAV:propdesc element describes the property or
1497 properties in the DAV:prop element it contains. All subsequent
1498 elements are descriptions that apply to those properties. All
1499 descriptions are optional and may appear in any order. Servers SHOULD
1500 support all the descriptions defined here, and MAY define others.
1502 DASL defines five descriptions. The first, DAV:datatype, provides a
1503 hint about the type of the property value, and may be useful to a
1504 user interface prompting for a value. The remaining four
1505 (DAV:searchable, DAV:selectable, DAV:sortable, and DAV:caseless)
1506 identify portions of the query (DAV:where, DAV:select, and
1507 DAV:orderby, respectively). If a property has a description for a
1508 section, then the server MUST allow the property to be used in that
1509 section. These descriptions are optional. If a property does not have
1510 such a description, or is not described at all, then the server MAY
1511 still allow the property to be used in the corresponding section.
1513 5.19.2.1 DAV:any-other-property
1515 This element can be used in place of DAV:prop to describe properties
1516 of WebDAV properties not mentioned in any other DAV:prop element. For
1517 instance, this can be used to indicate that all other properties are
1518 searchable and selectable without giving details about their types (a
1519 typical scenario for dead properties).
1521 5.19.3 The DAV:datatype Property Description
1523 The DAV:datatype element contains a single XML element that provides
1524 a hint about the domain of the property, which may be useful to a
1525 user interface prompting for a value to be used in a query. Datatypes
1526 are identified by an element name. Where appropriate, a server SHOULD
1527 use the simple datatypes defined in [XS2].
1529
1531 Examples from [XS2], section 3:
1533 +----------------+---------------------+
1534 | Qualified name | Example |
1535 +----------------+---------------------+
1536 | xs:boolean | true, false, 1, 0 |
1537 | | |
1538 | xs:string | Foobar |
1539 | | |
1540 | xs:dateTime | 1994-11-05T08:15:5Z |
1541 | | |
1542 | xs:float | .314159265358979E+1 |
1543 | | |
1544 | xs:integer | -259, 23 |
1545 +----------------+---------------------+
1547 If the data type of a property is not given, then the data type
1548 defaults to xs:string.
1550 5.19.4 The DAV:searchable Property Description
1552
1553 If this element is present, then the server MUST allow this property
1554 to appear within a DAV:where element where an operator allows a
1555 property. Allowing a search does not mean that the property is
1556 guaranteed to be defined on every resource in the scope, it only
1557 indicates the server's willingness to check.
1559 5.19.5 The DAV:selectable Property Description
1561
1563 This element indicates that the property may appear in the DAV:select
1564 element.
1566 5.19.6 The DAV:sortable Property Description
1568 This element indicates that the property may appear in the
1569 DAV:orderby element.
1571
1573 5.19.7 The DAV:caseless Property Description
1575 This element only applies to properties whose data type is
1576 "xs:string" and derived data types as per the DAV:datatype property
1577 description. Its presence indicates that compares performed for
1578 searches, and the comparisons for ordering results on the string
1579 property will be caseless (the default is character-by-character).
1581
1583 5.19.8 The DAV:operators XML Element
1585 The DAV:operators element describes every optional operator supported
1586 in a query. (Mandatory operators are not listed since they are
1587 mandatory and permit no variation in syntax.). All optional operators
1588 that are supported MUST be listed in the DAV:operators element. The
1589 listing for an operator consists of the operator (as an empty
1590 element), followed by one element for each operand. The operand MUST
1591 be either DAV:operand-property or DAV:operand-literal, which indicate
1592 that the operand in the corresponding position is a property or a
1593 literal value, respectively. If an operator is polymorphic (allows
1594 more than one operand syntax) then each permitted syntax MUST be
1595 listed separately.
1597
1598
1599
1600
1602
1604 5.19.9 Example of Query Schema for DAV:basicsearch
1606
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1634 This response lists four properties. The datatype of the last three
1635 properties is not given, so it defaults to xs:string. All are
1636 selectable, and the first three may be searched. All but the last may
1637 be used in a sort. Of the optional DAV operators, DAV:is-defined and
1638 DAV:like are supported.
1640 Note: The schema discovery defined here does not provide for
1641 discovery of supported values of the "caseless" attribute. This may
1642 require that the reply also list the mandatory operators.
1644 6. Internationalization Considerations
1646 Properties may be language-tagged using the xml:lang attribute (see
1647 [RFC2518], section 4.4). The optional operators DAV:language-defined
1648 (Section 5.12.1) and DAV:language-matches (Section 5.12.2) allow to
1649 express conditions on the language tagging information.
1651 7. Security Considerations
1653 This section is provided to detail issues concerning security
1654 implications of which DASL applications need to be aware. All of the
1655 security considerations of HTTP/1.1 also apply to DASL. In addition,
1656 this section will include security risks inherent in searching and
1657 retrieval of resource properties and content.
1659 A query must not allow one to retrieve information about values or
1660 existence of properties that one could not obtain via PROPFIND. (e.g.
1661 by use in DAV:orderby, or in expressions on properties.)
1663 A server should prepare for denial of service attacks. For example a
1664 client may issue a query for which the result set is expensive to
1665 calculate or transmit because many resources match or must be
1666 evaluated.
1668 7.1 Implications of XML External Entities
1670 XML supports a facility known as "external entities", defined in
1671 section 4.2.2 of [XML], which instruct an XML processor to retrieve
1672 and perform an inline include of XML located at a particular URI. An
1673 external XML entity can be used to append or modify the document type
1674 declaration (DTD) associated with an XML document. An external XML
1675 entity can also be used to include XML within the content of an XML
1676 document. For non-validating XML, such as the XML used in this
1677 specification, including an external XML entity is not required by
1678 [XML]. However, [XML] does state that an XML processor may, at its
1679 discretion, include the external XML entity.
1681 External XML entities have no inherent trustworthiness and are
1682 subject to all the attacks that are endemic to any HTTP GET request.
1683 Furthermore, it is possible for an external XML entity to modify the
1684 DTD, and hence affect the final form of an XML document, in the worst
1685 case significantly modifying its semantics, or exposing the XML
1686 processor to the security risks discussed in [RFC3023]. Therefore,
1687 implementers must be aware that external XML entities should be
1688 treated as untrustworthy.
1690 There is also the scalability risk that would accompany a widely
1691 deployed application which made use of external XML entities. In this
1692 situation, it is possible that there would be significant numbers of
1693 requests for one external XML entity, potentially overloading any
1694 server which fields requests for the resource containing the external
1695 XML entity.
1697 8. Scalability
1699 Query grammars are identified by URIs. Applications SHOULD not
1700 attempt to retrieve these URIs even if they appear to be retrievable
1701 (for example, those that begin with "http://")
1703 9. Authentication
1705 Authentication mechanisms defined in WebDAV will also apply to DASL.
1707 10. IANA Considerations
1709 This document uses the namespace defined by [RFC2518] for XML
1710 elements. All other IANA considerations mentioned in [RFC2518] are
1711 also applicable to DASL.
1713 11. Contributors
1715 This document is based on prior work on the DASL protocol done by the
1716 WebDAV DASL working group until the year 2000 -- namely by Alan
1717 Babich, Jim Davis, Rick Henderson, Dale Lowry, Saveen Reddy and
1718 Surendra Reddy.
1720 12. Acknowledgements
1722 This document has benefited from thoughtful discussion by Lisa
1723 Dusseault, Sung Kim, Elias Sinderson, Martin Wallmer, Jim Whitehead
1724 and Kevin Wiggen.
1726 Normative References
1728 [ACL] Clemm, G., Hopkins, A., Sedlar, E. and J. Whitehead,
1729 "WebDAV Access Control Protocol", ID
1730 draft-ietf-webdav-acl-12, October 2003, .
1733 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
1734 Requirement Levels", BCP 14, RFC 2119, March 1997.
1736 [RFC2518] Goland, Y., Whitehead, E., Faizi, A., Carter, S. and D.
1737 Jensen, "HTTP Extensions for Distributed Authoring --
1738 WEBDAV", RFC 2518, February 1999.
1740 [RFC2616] Fielding, R., Gettys, J., Mogul, J., Nielsen, H.,
1741 Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext
1742 Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
1744 [RFC3023] Makoto, M., St.Laurent, S. and D. Kohn, "XML Media Types",
1745 RFC 3023, January 2001.
1747 [RFC3253] Clemm, G., Amsden, J., Ellison, T., Kaler, C. and J.
1748 Whitehead, "Versioning Extensions to WebDAV", RFC 3253,
1749 March 2002.
1751 [XML] Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler,
1752 "Extensible Markup Language (XML) 1.0 (2nd ed)", W3C
1753 REC-xml, October 2000, .
1756 [XMLNS] Bray, T., Hollander, D. and A. Layman, "Namespaces in
1757 XML", W3C REC-xml-names, January 1999, .
1760 [XPATH] Clark, J. and S. DeRose, "XML Path Language (XPath)
1761 Version 1.0", W3C REC REC-xpath, November 1999, .
1764 [XS1] Thompson, H., Beech, D., Maloney, M., Mendelsohn, N. and
1765 World Wide Web Consortium, "XML Schema Part 1:
1766 Structures", W3C XS1, May 2001, .
1769 [XS2] Biron, P., Malhotra, A. and World Wide Web Consortium,
1770 "XML Schema Part 2: Datatypes", W3C XS2, May 2001, .
1773 Informative References
1775 [BIND] Clemm, G., Crawford, J., Reschke, J., Slein, J. and J.
1776 Whitehead, "Binding Extensions to WebDAV", ID
1777 draft-ietf-webdav-bind-02, June 2003, .
1780 [CaseMap] Davis, M., "Case Mappings", Unicode Techical Reports 21,
1781 February 2001, .
1784 [DASL] Reddy, S., Lowry, D., Reddy, S., Henderson, R., Davis, J.
1785 and A. Babich, "DAV Searching & Locating", ID
1786 draft-dasl-protocol-00, July 1999, .
1789 [DASLREQ] Davis, J., Reddy, S. and J. Slein, "Requirements for DAV
1790 Searching and Locating", ID draft-dasl-requirements-01,
1791 February 1999, .
1794 [SQL99] Milton, J., "Database Language SQL Part 2: Foundation
1795 (SQL/Foundation)", ISO ISO/IEC 9075-2:1999 (E), July 1999.
1797 URIs
1799 [1]
1801 [2]
1803 [3]
1806 [4]
1809 [5]
1812 [6]
1815 [7]
1818 [8]
1821 [9]
1824 [10]
1827 [11]
1830 [12]
1833 [13]
1836 Authors' Addresses
1838 Julian F. Reschke (editor)
1839 greenbytes GmbH
1840 Salzmannstrasse 152
1841 Muenster, NW 48159
1842 Germany
1844 Phone: +49 251 2807760
1845 Fax: +49 251 2807761
1846 EMail: julian.reschke@greenbytes.de
1847 URI: http://greenbytes.de/tech/webdav/
1849 Surendra Reddy
1850 Oracle Corporation
1851 600 Oracle Parkway, M/S 6op3
1852 Redwoodshores, CA 94065
1854 Phone: +1 650 506 5441
1855 EMail: Surendra.Reddy@oracle.com
1857 Jim Davis
1858 Intelligent Markets
1859 410 Jessie Street 6th floor
1860 San Francisco, CA 94103
1862 EMail: jrd3@alum.mit.edu
1864 Alan Babich
1865 FileNET Corp.
1866 3565 Harbor Blvd.
1867 Costa Mesa, CA 92626
1869 Phone: +1 714 327 3403
1870 EMail: ababich@filenet.com
1872 Appendix A. Three-Valued Logic in DAV:basicsearch
1874 ANSI standard three valued logic is used when evaluating the search
1875 condition (as defined in the ANSI standard SQL specifications, for
1876 example in ANSI X3.135-1992, section 8.12, pp. 188-189, section 8.2,
1877 p. 169, General Rule 1)a), etc.).
1879 ANSI standard three valued logic is undoubtedly the most widely
1880 practiced method of dealing with the issues of properties in the
1881 search condition not having a value (e.g., being null or not defined)
1882 for the resource under scan, and with undefined expressions in the
1883 search condition (e.g., division by zero, etc.). Three valued logic
1884 works as follows.
1886 Undefined expressions are expressions for which the value of the
1887 expression is not defined. Undefined expressions are a completely
1888 separate concept from the truth value UNKNOWN, which is, in fact,
1889 well defined. Property names and literal constants are considered
1890 expressions for purposes of this section. If a property in the
1891 current resource under scan has not been set to a value, then the
1892 value of that property is undefined for the resource under scan. DASL
1893 1.0 has no arithmetic division operator, but if it did, division by
1894 zero would be an undefined arithmetic expression.
1896 If any subpart of an arithmetic, string, or datetime subexpression is
1897 undefined, the whole arithmetic, string, or datetime subexpression is
1898 undefined.
1900 There are no manifest constants to explicitly represent undefined
1901 number, string, or datetime values.
1903 Since a Boolean value is ultimately returned by the search condition,
1904 arithmetic, string, and datetime expressions are always arguments to
1905 other operators. Examples of operators that convert arithmetic,
1906 string, and datetime expressions to Boolean values are the six
1907 relational operators ("greater than", "less than", "equals", etc.).
1908 If either or both operands of a relational operator have undefined
1909 values, then the relational operator evaluates to UNKNOWN. Otherwise,
1910 the relational operator evaluates to TRUE or FALSE, depending upon
1911 the outcome of the comparison.
1913 The Boolean operators DAV:and, DAV:or and DAV:not are evaluated
1914 according to the following rules:
1916 UNKNOWN and UNKNOWN = UNKNOWN
1918 UNKNOWN or UNKNOWN = UNKNOWN
1919 not UNKNOWN = UNKNOWN
1921 UNKNOWN and TRUE = UNKNOWN
1923 UNKNOWN and FALSE = FALSE
1925 UNKNOWN and UNKNOWN = UNKNOWN
1927 UNKNOWN or TRUE = TRUE
1929 UNKNOWN or FALSE = UNKNOWN
1931 UNKNOWN or UNKNOWN = UNKNOWN
1933 Appendix B. Change Log (to be removed by RFC Editor before publication)
1935 B.1 From draft-davis-dasl-protocol-xxx
1937 Feb 14, 1998 Initial Draft
1939 Feb 28, 1998 Referring to DASL as an extension to HTTP/1.1 rather
1940 than DAV.
1941 Added new sections "Notational Conventions", "Protocol Model",
1942 "Security Considerations".
1943 Changed section 3 to "Elements of Protocol".
1944 Added some stuff to introduction.
1945 Added "result set" terminology.
1946 Added "IANA Considerations".
1948 Mar 9, 1998 Moved sub-headings of "Elements of Protocol" to first
1949 level and removed "Elements of Protocol" Heading.
1950 Added an sentence in introduction explaining that this is a
1951 "sketch" of a protocol.
1953 Mar 11, 1998 Added orderby, data typing, three valued logic, query
1954 schema property, and element definitions for schema for
1955 basicsearch.
1957 April 8, 1998 - made changes based on last week's DASL BOF.
1959 May 8, 1998 Removed most of DAV:searcherror; converted to
1960 DAV:searchredirect
1961 Altered DAV:basicsearch grammar to use avoid use of ANY in DTD
1963 June 17, 1998 -Added details on Query Schema Discovery
1964 -Shortened list of data types
1966 June 23, 1998 moved data types before change history
1967 rewrote the data types section
1968 removed the casesensitive element and replace with the
1969 casesensitive attribute
1970 added the casesensitive attribute to the DTD for all operations
1971 that might work on a string
1973 Jul 20, 1998 A series of changes. See Author's meeting minutes for
1974 details.
1976 July 28, 1998 Changes as per author's meeting. QSD uses SEARCH, not
1977 PROPFIND.
1978 Moved text around to keep concepts nearby.
1979 Boolean literals are 1 and 0, not T and F.
1980 contains changed to contentspassthrough.
1982 Renamed rank to score.
1984 July 28, 1998 Added Dale Lowry as Author
1986 September 4, 1998 Added 422 as response when query lists
1987 unimplemented operators.
1988 DAV:literal declares a default value for xml:space, 'preserve'
1989 (see XML spec, section 2.10)
1990 moved to new XML namespace syntax
1992 September 22, 1998 Changed "simplesearch" to "basicsearch"
1993 Changed isnull to isdefined
1994 Defined NULLness as having a 404 or 403 response
1995 used ENTITY syntax in DTD
1996 Added redirect
1998 October 9, 1998 Fixed a series of typographical and formatting
1999 errors.
2000 Modified the section of three-valued logic to use a table rather
2001 than a text description of the role of UNKNOWN in expressions.
2003 November 2, 1998 Added the DAV:contains operator.
2004 Removed the DAV:contentpassthrough operator.
2006 November 18, 1998 Various author comments for submission
2008 June 3, 1999 Cosmetic and minor editorial changes only. Fix nits
2009 reported by Jim Whitehead in email of April 26, 1999. Converted to
2010 HTML from Word 97, manually.
2012 April 20, 2000 Removed redirection feature, since 301/302 suffices.
2013 Removed Query Schema Discovery (former chapter 4). Everyone agrees
2014 this is a useful feature, but it is apparently too difficult to
2015 define at this time, and it is not essential for DASL.
2017 B.2 since start of draft-reschke-webdav-search
2019 October 09, 2001 Added Julian Reschke as author.
2020 Chapter about QSD re-added.
2021 Formatted into RFC2629-compliant XML document.
2022 Added first comments.
2023 ID version number kicked up to draft-dasl-protocol-03.
2025 October 17, 2001 Updated address information for Jim Davis.
2026 Added issue of datatype vocabularies.
2027 Updated issue descriptions for grammar discovery, added issues on
2028 query schema DTD.
2030 Fixed typos in XML examples.
2032 December 17, 2001 Re-introduced split between normative and
2033 non-normative references.
2035 January 05, 2002 Version bumbed up to 04. Started work on resolving
2036 the issues identified in the previous version.
2038 January 14, 2002 Fixed some XML typos.
2040 January 22, 2002 Closed issues naming-of-elements. Fixed query search
2041 DTD and added option to discover properties of "other"
2042 (non-listed) properties.
2044 January 25, 2002 Changed into private submission and added reference
2045 to historic DASL draft. Marked reference to DASL requirements
2046 non-normative.
2047 Updated reference to latest deltav spec.
2049 January 29, 2002 Added feedback from and updated contact info for
2050 Alan Babich.
2051 Included open issues collected in http://www.webdav.org/dasl/
2052 protocol/issues.html.
2054 February 8, 2002 Made sure that all artwork fits into 72 characters
2055 wide text.
2057 February 18, 2002 Changed Insufficient storage handling
2058 (multistatus). Moved is-collection to operators and added to DTD.
2059 Made scope/depth mandatory.
2061 February 20, 2002 Updated reference to SQL99.
2063 February 28, 2002 "Non-normative References" -> "Informative
2064 References". Abstract updated. Consistently specify a charset when
2065 using text/xml (no change bars). Do not attempt to define
2066 PROPFIND's entity encoding (take out specific references to text/
2067 xml). Remove irrelevant headers (Connection:) from examples (no
2068 change bars). Added issue on querying based on DAV:href. Updated
2069 introduction to indicate relationship to DASL draft. Updated HTTP
2070 reference from RFC2068 to RFC2616. Updated XML reference to XML
2071 1.0 2nd edition.
2073 March 1, 2002 Removed superfluous namespace decl in 2.4.2. Reopened
2074 JW14 and suggest to drop xml:space support.
2076 March 3, 2002 Removed "xml:space" feature on DAV:literal. Added issue
2077 about string comparison vs. collations vs. xml:lang. Updated some
2078 of the open issues with details from JimW's original mail in April
2079 1999. Resolved scope vs relative URI references. Resolved issues
2080 about DAV:ascending (added to index) and the BNF for DAV:like
2081 (changed "octets" to "characters").
2083 March 8, 2002 Updated reference to DeltaV (now RFC3253). Added Martin
2084 Wallmer's comments, moved JW5 into DAV:basicsearch section.
2086 March 11, 2002 Closed open issues regaring the type of search
2087 arbiters (JW3) and their discovery (JW9). Rephrased requirements
2088 on multistatus response bodies (propstat only if properties were
2089 selected, removed requirement for responsedescription).
2091 March 23, 2002 RFC2376 -> RFC3023. Added missing first names of
2092 authors. OPTIONS added to example for DAV:supported-method-set.
2094 B.3 since draft-reschke-webdav-search-00
2096 March 29, 2002 Abstract doesn't refer to DASL WG anymore.
2098 April 7, 2002 Fixed section title (wrong property name
2099 supported-search-grammar-set. Changed DAV:casesensitve to
2100 "casesensitive" (it wasn't in the DAV: namespace after all).
2102 May 28, 2002 Updated some issues with Jim Davis's comments.
2104 June 10, 2002 Added proposal for different method for query schema
2105 discovery, not using pseudo-properties.
2107 June 25, 2002 QSD marshalling rewritten. Added issue
2108 "isdefined-optional".
2110 B.4 since draft-reschke-webdav-search-01
2112 July 04, 2002 Added issue "scope-collection".
2114 July 08, 2002 Closed issue "scope-collection".
2116 August 12, 2002 Added issues "results-vs-binds" and "select-allprop".
2118 October 22, 2002 Added issue "undefined-expressions".
2120 November 18, 2002 Changed example host names (no change tracking).
2122 November 25, 2002 Updated issue "DB2/DB7". Closed issues "undefined
2123 expressions", "isdefined-optional" and "select-allprop".
2125 B.5 since draft-reschke-webdav-search-02
2127 November 27, 2002 Added issues "undefined-properties",
2128 "like-exactlyone" and "like-wildcard-adjacent". Closed issue
2129 "query-on-href". Added acknowledgments section.
2131 November 28, 2002 Closed issue "like-exactlyone". Added issue
2132 "mixed-content-properties".
2134 December 14, 2002 Closed issues "undefined-properties",
2135 "results-vs-binds", "mixed-content-properties". Updated issue
2136 "like-wildcard-adjacent". Added informative reference to BIND
2137 draft. Updated reference to ACL draft.
2139 January 9, 2003 Removed duplicate section on invalid scopes. Added
2140 comments to some open issues. Closed issues JW25/26,
2141 score-pseudo-property and null-ordering.
2143 January 10, 2003 Issue limit-vs-ordering plus resolution. Closed
2144 issue JW17/JW24b.
2146 January 14, 2003 New issue order-precedence. Started resolution of
2147 DB2/DB7.
2149 January 15, 2003 Started spec of DAV:typed-literal.
2151 January 17, 2003 Fix one DAV:like/DAV:getcontenttype example (add /
2152 to like expression, make case-insensitive).
2154 January 28, 2003 Update issue(s) result-truncation, JW24d. Fixed
2155 response headers in OPTIONS example. Added issue qsd-optional.
2156 Closed issue(s) order-precedence, case-insensitivity-name.
2158 February 07, 2003 Added issue scope-vs-versions.
2159 score-pseudo-property: allow DAV:orderby to explicitly specify
2160 DAV:score.
2162 B.6 since draft-reschke-webdav-search-03
2163 April 24, 2003 Fixed two "?" vs "_" issues (not updated in last
2164 draft).
2166 June 13, 2003 Improve index.
2168 B.7 since draft-reschke-webdav-search-04
2170 July 7, 2003 Typo fixed (propstat without status element).
2172 August 11, 2003 Remove superfluous IP and copyright sections.
2174 September 09, 2003 Added issues "2.4-multiple-uris" and
2175 "5.1-name-filtering".
2177 October 06, 2003 Fix misplaced section end in 5.11, add table
2178 formatting. Enhance table formatting in 5.18.3. Updated ACL and
2179 BIND references. Added XPATH reference. Closed issue JW24d by
2180 adding new optional operators. Updated more open issues, added
2181 issues from January meeting. Add K. Wiggen to Acknowledgements.
2182 Add Contributors section for the authors of the original draft.
2183 Close issue "scope-vs-versions" (optional feature added). Close
2184 (new) issue "1.3-import-DTD-terminology". Add issue
2185 "1.3-import-requirements-terminology".
2187 October 07, 2003 Typos fixed. Moved statement about DAV: namespace
2188 usage into separate (sub-)section. Closed
2189 "1.3-import-requirements-terminology". Update I18N Considerations
2190 with new xml:lang support info (see issue JW24d). Close issue
2191 "DB2/DB7" (remaining typing issues are now summarized in issue
2192 "typed-literal"). Fix misplaced section end in section 7. Started
2193 change to use RFC3253-style method definitions and error
2194 marshalling.
2196 October 08, 2003 Remove obsolete language that allowed reporting
2197 invalid scopes and such inside multistatus. Add new issue
2198 "5.4.2-scope-vs-redirects".
2200 Appendix C. Resolved issues (to be removed by RFC Editor before
2201 publication)
2203 Issues that were either rejected or resolved in this version of this
2204 document.
2206 C.1 1.3-import-condition-code-terminology
2208 Type: change
2210 [3]
2212 julian.reschke@greenbytes.de (2003-10-05): Import RFC3253 pre/
2213 postcondition code terminology and use it throughout the document to
2214 identify conditions.
2216 Resolution: Section 2.5 rewritten.
2218 C.2 1.3-import-requirements-terminology
2220 Type: change
2222 julian.reschke@greenbytes.de (2003-10-06): Import terminology from
2223 DASLREQ.
2225 Resolution: Done.
2227 C.3 1.3-import-DTD-terminology
2229 Type: change
2231 [4]
2233 julian.reschke@greenbytes.de (2003-09-27): Import DTD usage notes
2234 from ordering spec.
2236 C.4 invalid-scope
2238 Type: change
2240 julian.reschke@greenbytes.de (2003-01-09): Marshalling a BAD REQUEST
2241 with an (extended) multistatus body seems to be a weird approach.
2242 Should be resolved by finally adopting the RFC3253 error marshalling.
2244 julian.reschke@greenbytes.de (2003-01-28): Funny enough, Roy
2245 Fielding's feedback on a related issue indicates that this may be the
2246 absolutely right thing to do. Needs coordination with RFC2518bis
2247 activity.
2249 Resolution: Document style change to use RFC3253 preconditions.
2251 C.5 JW24d
2253 Type: edit
2255 [5]
2257 ejw@ics.uci.edu (2000-04-20): Where does xml:lang go in a query?
2259 julian.reschke@greenbytes.de (2002-02-28): What would be the
2260 *purpose* of putting xml:lang into a query?
2262 jrd3@alum.mit.edu (2002-05-28): The purpose is to allow one to
2263 express queries more precisely, e.g. to distinguish between the
2264 English word "hoop" (a circular object) and Dutch "hoop" (hope).
2265 Imagine a property that holds keywords for a resource. See 4.4 in
2266 http://www.ietf.org/rfc/rfc2518.txt, and 2.12 in http://www.w3.org/
2267 TR/REC-xml
2269 julian.reschke@greenbytes.de (2002-05-28): I think this would be an
2270 interesting feature, but it seems to be extremely hard to implement.
2271 So assuming a query that - the query specifies a language and - be
2272 the text content of the property matches The result will be: 1) true
2273 (match), if the property was stored with a matching xml:lang property
2274 (where the language tag matching rules would have to apply) 2)
2275 undefined if the property was stored without xml:lang 3) false
2276 otherwise On the other hand if - the query doesn't specify a language
2277 the result will be: 4) undefined (at least according to the current
2278 wording). So, 1) requires that the query engine actually knows how to
2279 match language tags -- I'm not sure that everybody is willing to
2280 implement that. 2) is this desirable? 3) ok. 4) that seems to be
2281 wrong. If the query doesn't care, it should match, right? Other
2282 problems: - what is the language of a date-typed property? - (sic!)
2283 where should xml:lang go into the query? There's no XML feature to
2284 undefine an xml:lang which is in scope, but there may be cases where
2285 this is needed. On the other hand, if we drop this requirement, a
2286 client can still do a query and then process the result set -- the
2287 property elements in the response body will be reported with xml:lang
2288 (when persisted with language) anyway. So I'd recommend to drop the
2289 feature. Defining string comparisons vs. collation sequences is hard
2290 enough.
2292 julian.reschke@greenbytes.de (2003-01-09): (Proposal to reject)
2294 julian.reschke@greenbytes.de (2003-01-28): WG meeting feedback:
2295 should be moved into explicit operators (see proposal on mailing
2296 list). Open: is this optional or required?
2297 Resolution: Add new optional operators.
2299 C.6 scope-vs-versions
2301 Type: change
2303 [6]
2305 julian.reschke@greenbytes.de (2003-02-05): A relatively frequent use
2306 case for servers that both support versioning and DASL seems to have
2307 searches that include all versions of the resources in scope. In
2308 general, the version URIs may not be in the scope of the query.
2309 Therefore, I'd like to extend the DAV:scope to specify inclusion of
2310 versions. This would be an optional extension -- however, a server
2311 that does not support his feature should reject the request (so that
2312 the client would know that the request could not be satisfied).
2313 Example: /container1/
2314 d:href> infinity
2315
2317 Martin.Wallmer@softwareag.com (2003-02-06): just to clarify: 1. If a
2318 resource in scope has versions, the server SHOULD take care of
2319 versions as well. 2. If the client specifies ,
2320 the server MUST take care of versions or MUST reject the request. 3.
2321 If the user does not want to get versions, he must specify ... Is
2323 my understanding correct? However, a defined "switch" (include -
2324 exclude) could be a good hint for the server in terms of performance,
2325 so I'd prefer a as well. Alternatively the
2326 server should only include the versions, if is
2327 specified. Does this make sense?
2329 julian.reschke@greenbytes.de (2003-02-06): I don't like that, because
2330 I'd prefer to keep the definition of "scope" intact. If versions
2331 happen to be in the namespace scope, they should be in scope of the
2332 search as well. Thus the proposal to add a specific element that
2333 *extends* the scope of the query.
2335 C.7 DB2/DB7
2337 Type: change
2339 [7]
2341 ejw@ics.uci.edu (2000-04-20): Dates (HTTPDate in getlastmodified).
2343 ejw@ics.uci.edu (2000-04-20): Agreement that it is OK to submit
2344 isodate to search HTTPDate (i.e., it's a marshalling issue only).
2346 ejw@ics.uci.edu (2000-04-20): Booleans appear to be underspecified in
2347 the specification. How is a boolean tested, and what are the behavior
2348 of operators like less than, greater than, etc.
2350 julian.reschke@greenbytes.de (2002-01-28): I think similar questions
2351 apply to booleans. Proposal: allow specification of the literal's
2352 type using XML Schema simple types, and declare that "both" WebDAV
2353 date types are compatible.
2355 ABabich@filenet.com (2002-01-29): The current DASL draft doesn't
2356 really have Booleans or any other data type. It's trying to skate on
2357 data types. Booleans could be tested using the "eq" and the
2358 combination "not eq", if you had well defined literals for TRUE and
2359 FALSE. With the current syntax, that is the way you would have to
2360 test a Boolean. Generally, Boolean values are not considered to be
2361 ordered, so "gt" etc. wouldn't apply. However, if the literal values
2362 of a Boolean were 1 and 0 for TRUE and FALSE (using the most commonly
2363 used convention of positive logic), then you would have an obvious
2364 ordering. 1 and 0 have the advantage of being language independent.
2365 You now see a lot of electronic and electro-mechanical devices (air
2366 conditioners, computers, etc.) with a "1/0" label on the power
2367 switch, "1" meaning "on", and "0" meaning "off". SQL databases don't
2368 have Booleans. SQL doesn't control DASL, of course, but SQL databases
2369 are so widely used that they are important. The closest thing in SQL
2370 is a bit field. Each bit in a bit field is zero or 1. So, why not
2371 close the issue by saying: DASL doesn't have data types. You can
2372 simulate Booleans by an integer data type, using 1 for "TRUE" and 0
2373 for "FALSE".
2375 julian.reschke@greenbytes.de (2002-10-22): let's consider a dead
2376 property "foo", and some resources a, b and c on which this dead
2377 property is defined and has the values "1", "3" and "10". Consider a
2378 DAV:basicsearch with the where clause: 3 Which resource will
2380 match? As DAV:basicsearch currently isn't type-aware, the server will
2381 have to do a string comparison, and only the b (with value "3") will
2382 match. Is this really sufficient? It basically means that dead
2383 property comparisons are restricted to strings. Proposals: a) If the
2384 server happens to have type information for a dead property, it
2385 should try to do a comparison according to the known property type,
2386 if the literal can be parsed into this type. This basically
2387 replicates the behaviour that a client would expect when querying on
2388 live properties such as DAV:getcontentlength, so it could be taken as
2389 a simple clarification. Extended proposal: b) A client can enforce
2390 comparison using a specific data type by specifying the type in the
2391 query, for instance using:
2392 prop> 3
2393 Martin.Wallmer@softwareag.com (2002-11-25): What about existing
2394 implementations? Currently a server might react with "xsi:type
2395 unknown entity" or just ignore it (which would mean: String
2396 comparison)
2398 julian.reschke@greenbytes.de (2002-11-25): OK, how about *adding* an
2399 alternative to DAV:literal? Therefore: DAV:literal: untyped, server
2400 can compare according to it's internal knowledge of types (with the
2401 clarification above) DAV:typed-literal: typed according to the
2402 xsi:type attribute -- "new" servers can implement this without
2403 affecting any existing code. We'll need to think about discovery of
2404 this feature, though. It might be possible to do this with QSD (in
2405 the meantime, are there any QSD implementations except ours?)
2407 Resolution: WG meeting feedback: define DAV:typed-literal. Also allow
2408 DAV:literal to be evaluated by the server according "internal" type
2409 knowledge. Require timestamps to be ISO, even for
2410 DAV:getlastmodified.
2412 Appendix D. Open issues (to be removed by RFC Editor before publication)
2414 D.1 1.3-apply-condition-code-terminology
2416 Type: change
2418 julian.reschke@greenbytes.de (2003-10-07): (Umbrella issue that will
2419 be left open until RFC3253 condition terminlogy is used throughout
2420 the document)
2422 D.2 2.4-multiple-uris
2424 Type: change
2426 julian.reschke@greenbytes.de (2003-09-09): However, the set of URIs
2427 for a given resource may be unlimited due to possible bind loops.
2428 Therefore consider to report just one URI per resource.
2430 D.3 result-truncation
2432 Type: change
2434 [8]
2436 ldusseault@xythos.com (2002-03-29): I believe the same response body
2437 that contains the first N elements should also contain
2438 a *different* element stating that the results were incomplete and
2439 the result set was truncated by the server. There may also be a need
2440 to report that the results were incomplete and the result set was
2441 truncated at the choice of the client (isn't there a limit set in the
2442 client request?) That's important so the client knows the difference
2443 between receiving 10 results because there were >10 but only 10 were
2444 asked for, and receiving 10 results because there were only exactly
2445 10 results and it just happens that 10 were asked for.
2447 jrd3@alum.mit.edu (2002-05-28): I agree that this could be useful,
2448 but I think this issue should be consolidated with issue JW5 (see
2449 below), which proposes that DASL basicsearch ought to have a way for
2450 client to request additional result sets. It should be moved because
2451 there is little or no value in allowing a client to distinguish
2452 between the case where "N results were requested, and there are
2453 exactly N available" and "N results were requested, and there are
2454 more than N available" if there is no way for client to get the next
2455 batch of results.
2457 julian.reschke@greenbytes.de (2003-01-28): Feedback from interim WG
2458 meeting: agreement that marshalling should be rewritten and backwards
2459 compatibility is not important. Proposal: extend DAV:multistatus by a
2460 new child element that indicates (1) the range that was returned, (2)
2461 the total number of results and (3) a URI identifying the result (for
2462 resubmission when getting the "next" results). Such as ...identifier for result set...
2464 href> <-- number of results --> <-- 1-based
2465 index of 1st result --> <-- size of result set
2466 returned --> <-- indicates that this is a
2467 partial result --> ...response elements for search
2468 results... The example below would then translate to:
2469 HTTP/1.1 207 Multistatus Content-Type: text/xml; charset="utf-8"
2470 Content-Length: xxx
2471
2472 http://www.example.net/
2473 sounds/unbrokenchain.au
2474 HTTP/1.1 200 OK
2475 http://tech.mit.test/archive96/photos/
2476 Lesh1.jpg HTTP/1.1 200 OK
2477 D:status> Q: do we need
2478 all elements, in particular start and length?
2480 julian.reschke@greenbytes.de (2003-10-07): Related: if this is
2481 supposed to be normative to DAV:basicsearch, it can't stay in an
2482 "example" sub-section.
2484 D.4 qsd-optional
2486 Type: change
2488 julian.reschke@greenbytes.de (2003-01-28): WG January meeting
2489 feedback: QSD should be made required.
2491 kwiggen@xythos.com (2003-10-03): (significant pushback, see mailing
2492 list thread at http://lists.w3.org/Archives/Public/www-webdav-dasl/
2493 2003OctDec/0003.html).
2495 D.5 5.1-name-filtering
2497 Type: change
2499 [9]
2501 julian.reschke@greenbytes.de (2003-09-08): This query grammar
2502 supports properties and content, but not conditions on URL elements
2503 (such as the last segment that many WebDAV implementations treat as
2504 "file name"). Discuss possible extension such as adding name filters
2505 to the scope, or adding a specific operator.
2507 D.6 5.4.2-multiple-scope
2509 Type: change
2511 [10]
2513 prakash.yamuna@covigna.com (2003-09-27): (asks for the ability to
2514 specify multiple scopes in a single query)
2516 julian.reschke@greenbytes.de (2003-10-03): Consider making this an
2517 optional extension iff we can come up with a simple enough definition
2518 of it's impact on sorting/ranking and so on. Otherwise propose to
2519 reject.
2521 D.7 5.4.2-scope-vs-redirects
2523 Type: change
2525 [11]
2527 julian.reschke@greenbytes.de (2003-10-08): Clarify the relation of
2528 scope and redirect (3xx) resources.
2530 D.8 language-comparison
2532 Type: change
2534 [12]
2536 julian.reschke@greenbytes.de (2002-03-03): XPath/XQuery (see draft,
2537 and open issue) specify string comparisons based on collations, not
2538 languages. I think we should adopt this. This would mean that
2539 "xml:lang" would be removed, and an optional attribute specifying the
2540 name of the collation is added.
2542 julian.reschke@greenbytes.de (2003-01-09): Proposal: adopt "lang" and
2543 "collation" attribute from XSLT 2.0's xsl:sort.
2545 D.9 JW16b/JW24a
2547 Type: change
2549 [13]
2551 ejw@ics.uci.edu (2000-04-20): Define how comparisons on strings work,
2552 esp for i18n. Need policy statement about sort order in various
2553 national languages. (JW said "non-Latin" but it's an issue even in
2554 languages that use the latin char set.)
2555 julian.reschke@greenbytes.de (2003-01-28): This issue not only
2556 applies to the comparison operators, but also to ordering!
2558 D.10 typed-literal
2560 Type: change
2562 julian.reschke@greenbytes.de (2003-01-15): 1. (insert language
2563 defining the comparison following the rules defined in http://
2564 www.w3.org/TR/xpath20/#id-comparisons). 2. Extend Basicsearch QSD
2565 grammar to support discovery of typed-literal 3. Update DTD. 4.
2566 Discuss behaviour of DAV:literal when the property's type is known
2567 for the complete search scope (is the server allowed to be "smart"?)
2569 Index
2571 C
2572 caseless attribute 27, 33
2573 Criteria 5
2575 D
2576 DAV:and 27
2577 DAV:ascending 26
2578 DAV:contains 31
2579 DAV:depth 23
2580 DAV:descending 26
2581 DAV:eq 27
2582 caseless attribute 27
2583 DAV:from 23
2584 DAV:gt 27
2585 DAV:gte 27
2586 DAV:include-versions 23
2587 DAV:is-collection 30
2588 DAV:is-defined 30
2589 DAV:language-defined 29
2590 DAV:language-matches 29
2591 DAV:like 30
2592 DAV:limit 33
2593 DAV:literal 27
2594 DAV:lt 27
2595 DAV:lte 27
2596 DAV:not 27
2597 DAV:nresults 33
2598 DAV:or 27
2599 DAV:orderby 26
2600 DAV:scope 23
2601 DAV:score 32
2602 relationship to DAV:orderby 33
2603 DAV:search-grammar-discovery-supported precondition 10
2604 DAV:search-grammar-supported precondition 10
2605 DAV:search-scope-valid precondition 10
2606 DAV:select 23
2607 DAV:supported-query-grammar-set
2608 property 15
2609 DAV:typed-literal 28
2610 DAV:where 24
2612 O
2613 OPTIONS method 14
2614 DASL response header 14
2616 P
2617 Preconditions
2618 DAV:search-grammar-discovery-supported 10
2619 DAV:search-grammar-supported 10
2620 DAV:search-scope-valid 10
2622 Q
2623 Query Grammar Discovery 14
2624 using live property 15
2625 using OPTIONS 14
2626 Query Grammar 6
2627 Query Schema 6
2628 Query 5
2630 R
2631 Result Record Definition 6
2632 Result Record 6
2633 Result Set Truncation
2634 Example 11
2635 Result Set 6
2636 Result 6
2638 S
2639 Scope 6
2640 SEARCH method 9
2641 Search Modifier 6
2642 Sort Specification 6
2644 Intellectual Property Statement
2646 The IETF takes no position regarding the validity or scope of any
2647 intellectual property or other rights that might be claimed to
2648 pertain to the implementation or use of the technology described in
2649 this document or the extent to which any license under such rights
2650 might or might not be available; neither does it represent that it
2651 has made any effort to identify any such rights. Information on the
2652 IETF's procedures with respect to rights in standards-track and
2653 standards-related documentation can be found in BCP-11. Copies of
2654 claims of rights made available for publication and any assurances of
2655 licenses to be made available, or the result of an attempt made to
2656 obtain a general license or permission for the use of such
2657 proprietary rights by implementors or users of this specification can
2658 be obtained from the IETF Secretariat.
2660 The IETF invites any interested party to bring to its attention any
2661 copyrights, patents or patent applications, or other proprietary
2662 rights which may cover technology that may be required to practice
2663 this standard. Please address the information to the IETF Executive
2664 Director.
2666 Full Copyright Statement
2668 Copyright (C) The Internet Society (2003). All Rights Reserved.
2670 This document and translations of it may be copied and furnished to
2671 others, and derivative works that comment on or otherwise explain it
2672 or assist in its implementation may be prepared, copied, published
2673 and distributed, in whole or in part, without restriction of any
2674 kind, provided that the above copyright notice and this paragraph are
2675 included on all such copies and derivative works. However, this
2676 document itself may not be modified in any way, such as by removing
2677 the copyright notice or references to the Internet Society or other
2678 Internet organizations, except as needed for the purpose of
2679 developing Internet standards in which case the procedures for
2680 copyrights defined in the Internet Standards process must be
2681 followed, or as required to translate it into languages other than
2682 English.
2684 The limited permissions granted above are perpetual and will not be
2685 revoked by the Internet Society or its successors or assignees.
2687 This document and the information contained herein is provided on an
2688 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
2689 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
2690 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
2691 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
2692 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
2694 Acknowledgment
2696 Funding for the RFC Editor function is currently provided by the
2697 Internet Society.