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'XS2' == Outdated reference: A later version (-27) exists of draft-ietf-webdav-bind-02 -- No information found for draft-dasl-protocol - is the name correct?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/ 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: 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... <-- 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 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. 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