Network Working Group R J. Godoy Internet-Draft H. Minni Intended status: Experimental Universidad Nacional del Litoral Expires: July 16, 2008 January 13, 2008 A WebDAV Search Grammar for XML Properties draft-godoy-webdav-xmlsearch-00 Status of This Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on July 16, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract This document specifies XS:xml-search, a search grammar for use with the Web Distributed Authoring and Versioning (WebDAV) SEARCH protocol. XS:xml-search extends the DAV:basicsearch grammar with XPath expressions which are evaluated on properties whose values are XML fragments. The full expression power of XPath may exceed the requirement in simple use cases, therefore some provisions are made in order to Godoy & Minni Expires July 16, 2008 [Page 1] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 reduce the cost of implementing this specification, as well as the computational cost of evaluating allowed queries. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Notational conventions . . . . . . . . . . . . . . . . . . 4 1.2. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4. XS:xml-search and the PROPFIND response . . . . . . . . . 7 2. XPath . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1. Static and Dynamic Contexts . . . . . . . . . . . . . . . 8 2.2. Error and warnings . . . . . . . . . . . . . . . . . . . . 10 2.2.1. Warnings . . . . . . . . . . . . . . . . . . . . . . . 10 2.2.2. Errors (in SAP) . . . . . . . . . . . . . . . . . . . 10 2.2.3. Errors (in DEP) . . . . . . . . . . . . . . . . . . . 11 2.3. Numeric Predicates . . . . . . . . . . . . . . . . . . . . 12 3. Discovery of the Query Grammar . . . . . . . . . . . . . . . . 13 3.1. The DASL Response Header . . . . . . . . . . . . . . . . . 13 3.2. DAV:supported-query-grammar-set . . . . . . . . . . . . . 13 3.3. Discovery of the XS:xml-search Query Schema . . . . . . . 13 4. The XS:xml-search Grammar . . . . . . . . . . . . . . . . . . 15 4.1. Accepted Role Precondition . . . . . . . . . . . . . . . . 15 4.2. Selection . . . . . . . . . . . . . . . . . . . . . . . . 16 4.3. Query criteria . . . . . . . . . . . . . . . . . . . . . . 18 4.3.1. DAV:prop operand . . . . . . . . . . . . . . . . . . . 18 4.3.2. Literal Operands . . . . . . . . . . . . . . . . . . . 19 4.3.3. Relational operators . . . . . . . . . . . . . . . . . 19 4.3.4. The XS:filter operator . . . . . . . . . . . . . . . . 20 4.3.5. The XS:is-well-formed operator . . . . . . . . . . . . 20 4.4. Ordering . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.5. SEARCH Status Codes for responses to XS:xml-search queries . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.6. Status Codes for Use in 'response' Elements . . . . . . . 21 4.7. Status Codes for Use in 'propstat' Elements . . . . . . . 22 4.8. Precondition and postcondition Codes . . . . . . . . . . . 22 4.8.1. XS:property-must-be-well-formed-xml . . . . . . . . . 22 4.8.2. XS:acceptable-role . . . . . . . . . . . . . . . . . . 22 4.8.3. XS:XPath-error . . . . . . . . . . . . . . . . . . . . 23 4.8.4. DAV:search-scope-valid . . . . . . . . . . . . . . . . 23 4.8.5. XS:known-literal-type . . . . . . . . . . . . . . . . 23 5. Query Schema for XS:xml-search . . . . . . . . . . . . . . . . 23 5.1. Property descriptions . . . . . . . . . . . . . . . . . . 24 5.2. Operator descriptions . . . . . . . . . . . . . . . . . . 25 5.2.1. XS:opdesc-rule and XS:operator . . . . . . . . . . . . 26 5.2.2. XS:repetition . . . . . . . . . . . . . . . . . . . . 27 5.2.3. XS:alternative . . . . . . . . . . . . . . . . . . . . 27 5.2.4. Implied operator description . . . . . . . . . . . . . 27 Godoy & Minni Expires July 16, 2008 [Page 2] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 5.2.5. Extended operator description for DAV:typed-literal Operand . . . . . . . . . . . . . . 29 6. XML Extensibility . . . . . . . . . . . . . . . . . . . . . . 30 7. Security Considerations . . . . . . . . . . . . . . . . . . . 31 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 31 9.1. Normative References . . . . . . . . . . . . . . . . . . . 31 9.2. Informative References . . . . . . . . . . . . . . . . . . 33 Editorial Comments . . . . . . . . . . . . . . . . . . . . . . . . 33 Appendix A. Example XS:xml-search query . . . . . . . . . . . . . 35 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Godoy & Minni Expires July 16, 2008 [Page 3] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 1. Introduction This document specifies XS:xml-search, an OPTIONAL search grammar for use with the Web Distributed Authoring and Versioning (WebDAV) SEARCH protocol. The search grammar defined by this document is a superset of DAV:basicsearch [I-D.reschke-webdav-search]. The intent of this document is to extend the DAV:basicsearch grammar for dealing with properties whose values are XML fragments. Since the WebDAV property namespace is flat, and resources may have at most one value for a property of a given name (Section 9.1 of [RFC4918]), XML documents allowing repeatable elements cannot be expressed as a set of independent WebDAV properties (i.e by mapping some elements to properties), and the DAV:basicsearch schema cannot be applied to such XML content because it deals with property values as a whole. [note- intent] XS:xml-search is proposed as a different search grammar because it defines a new element (namely XS:filter) that modify the query semantics. Had this been an extension of DAV:basicsearch, a server would have ignored the XS:filter elements (according to Section 17 of [RFC4918]) yielding results different from those requested by the client. [note-RFC4918-sect17] 1.1. Notational conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. This specification defines elements in the urn:ietf:params:xml:ns:webdav-xml-search XML namespace. (hereinafter referred to as the "XS namespace", though the prefix binding "XS:" is not normative). In natural language, an element like "xml-search" in this namespace is sometimes referred to as "XS:xml-search" (without quotes). [note-namespace]. In element definitions, an element name prefixed with "XS:" refers to an element in the XS namespace, and un-prefixed element names refers to elements in the "DAV:" namespace. The DTD fragments are normative up to extensibility rules defined in Section 6. Unless noted otherwise, ordering of declared content is not significative. Note: when an error condition is described, it is said that "the server MUST return" some indication of that error. Unless stated otherwise, if several errors occurs at the same time, any of them MAY Godoy & Minni Expires July 16, 2008 [Page 4] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 be reported and any of them MAY be omitted as long as one of them is reported. 1.2. Terms This document uses the terms defined in [RFC2616], [RFC4918], [W3C.PR-xpath20-20061121] and this section. Some definitions of frequently used terms from [W3C.PR-xpath20-20061121] are informatively included here. Dynamic Context: (of an XPath expression) "the dynamic context of an expression is defined as information that is available at the time the expression is evaluated." (Section 2.1.2, [W3C.PR-xpath20-20061121]) Dynamic Evaluation Phase (DEP): "The dynamic evaluation phase is the phase during which the value of an expression is computed. It occurs after completion of the static analysis phase." (Section 2.3.3.2, [W3C.PR-xpath20-20061121]) Dynamic Error: "A dynamic error is an error that must be detected during the dynamic evaluation phase and may be detected during the static analysis phase. Numeric overflow is an example of a dynamic error." (Section 2.3.1, [W3C.PR-xpath20-20061121]) Implementation-defined: "indicates an aspect that MAY differ between implementations, but MUST be specified by the implementor for each particular implementation." (Section 1, [W3C.PR-xpath20-20061121]) Implementation-dependent: "indicates an aspect that MAY differ between implementations, is not specified by [this or any other] specification, and is not required to be specified by the implementor for any particular implementation." (Section 1, [W3C.PR-xpath20-20061121]) Role: a context within XS:xml-search where the DAV:prop element is expected. A role is "plain" if the DAV:prop element occurs as a direct child of DAV:select, DAV:where, or DAV:order, and it is "filtered" (also referred as XPath-enabled) if the DAV:prop element occurs as a direct child of XS:XPath. Static Analysis Phase (SAP): "The static analysis phase depends on the expression itself and on the static context. The static analysis phase does not depend on input data (other than schemas)." (Section 2.3.3.1, [W3C.PR-xpath20-20061121]) Static Context: (of an XPath expression) "the static context of an expression is the information that is available during static Godoy & Minni Expires July 16, 2008 [Page 5] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 analysis of the expression, prior to its evaluation." (Section 2.1.1, [W3C.PR-xpath20-20061121]) Static Error: "A static error is an error that MUST be detected during the static analysis phase. A syntax error is an example of a static error." (Section 2.3.1, [W3C.PR-xpath20-20061121]) Type Error: "A type error may be raised during the static analysis phase or the dynamic evaluation phase. During the static analysis phase, a type error occurs when the static type of an expression does not match the expected type of the context in which the expression occurs. During the dynamic evaluation phase, a type error occurs when the dynamic type of a value does not match the expected type of the context in which the value occurs." (Section 2.3.1, [W3C.PR-xpath20-20061121]) 1.3. Overview Section 1.4 summarizes how this query grammar matches the PROPFIND response, according to the requirement imposed by Section 2.3.2 of [I-D.reschke-webdav-search]. Section 2 describes XS:xml-search as an XPath host language, i.e., a language where XPath expressions are embedded. Some items from the XPath specification are defined in that section, while other are left to the criteria of the implementors. This section also includes design decisions in order to reduce the implementation cost of this specification, as well as the computational cost of allowed queries. Section 3 describes how this grammar is advertised, according to the mechanisms for discovery of supported query grammars, defined in Section 3 of [I-D.reschke-webdav-search]. This include the Allow and DASL headers in OPTIONS responses (Section 3.1), the DAV:supported- query-grammar-set property (Section 3.2) and Query Schema Discovery (Section 3.3 and Section 5). Section 4 describes the grammar of a XS:xml-search query. This includes extending the specification of selection (Section 4.2) query criteria (Section 4.3) and ordering (Section 4.4) with respect to DAV:basicsearch. Additionally, some status (Section 4.5 to Section 4.7) and precondition/postcondition codes (Section 4.8) are defined. Section 5 describes the Query Schema for advertising supported features about properties (Section 5.1) and operators (Section 5.2) available in a XS:xml-search query. Section 6 describes the specified behaviour when unexpected elements Godoy & Minni Expires July 16, 2008 [Page 6] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 are found, providing a common ground for allowing clients that implement arbitrary extensions to interoperate with other implementations which does not include it. 1.4. XS:xml-search and the PROPFIND response A XS:xml-search response describes a subset of the elements which are described by a PROPFIND response that lists the same properties on the same scope and with the same depth. If a server supports specifying several scopes in a single query, and these scopes exist, then the XS:xml-search response will describe a subset of the elements in several PROPFIND responses (one PROPFIND for each scope). The properties included in a XS:xml-search response are those specified within the DAV:select element of the request. In that context, DAV:allprop and DAV:prop are understood as in PROPFIND, hence both methods returns the same properties. In addition, XS:xml- search introduce a new way for selecting properties: XS:filter, which "filters" elements from some property value according to an XPath expression. If XS:filter is used, the XS:xml-search response will contain a subset of elements from the filtered property, while the PROPFIND response will contain the complete value. Queries may impose conditions about which or how many resources will be included in the response, and servers may truncate the response at their choice. Thus, a SEARCH response may not include some resources from the specified scope, while all of them have to be included when using PROPFIND. Furthermore, XS:xml-search defines additional preconditions and postconditions codes that are not used with a PROPFIND response. 2. XPath There are several items in XPath that are implementation-defined. Some of them are defined in this section (as this protocol specifies an XPath host language) while other are left to the criteria of the implementors. * Some components of the static and dynamic contexts are constrained (Section 2.1). * A way for reporting errors and warnings is specified (Section 2.2). * In some expressions, supporting numeric predicates is OPTIONAL (section Section 2.3). * Implementations of this protocol MUST be based on the rules of Godoy & Minni Expires July 16, 2008 [Page 7] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 [W3C.REC-xml11-20060816] and [W3C.REC-xml-names11-20060816], and apply them consistently. * The self, child, and attribute axes MUST be supported. An implementation MAY support other axes, as described in the query schema. (Note: the abbreviated steps ".." and "//" are not supported, unless the parent and descendant-or-self axes respectively are supported.) * Support for the "Static Typing Feature" and "Static Typing Extensions" (Appendix F.1 of [W3C.PR-xpath20-20061121]) is implementation-defined. 2.1. Static and Dynamic Contexts This specification defines REQUIRED values for some components of the XPath static and dynamic context. Unless specified otherwise, the constant values specified below MUST NOT be overwritten. Components not listed here are "implementation-dependent". Evaluation of an expression that relies on one or more "unassigned" components raises the static error err:XPST0001 (if the component is static) or the dynamic error err:XPDY0002 (if the component is dynamic). REQUIRED static values +---------------------+---------------------------------------------+ | Component | Specified Value | +---------------------+---------------------------------------------+ | XPath 1.0 | "false". | | compatibility mode | | | | | | Statically known | All the namespace bindings in scope at the | | namespaces | XS:XPath element where the expression | | | occurs plus ("fn:", | | | "http://www.w3.org/2005/ XPath- functions") | | | unless overwritten. | | | | | Default | The default namespace of the XS:XPath | | element/type | element where the expression occurs ("none" | | namespace | if there is no default namespace). | | | | | Default function | None. | | namespace | | | | | | Function signatures | None (may be overwritten). | | | | Godoy & Minni Expires July 16, 2008 [Page 8] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 | Statically known | At least | | collations | "http://www.iana.org/assignments/collation/ | | | default" and applicable wildcard collations | | | (Sections 3.1 and 3.2 of [RFC4790]). MAY | | | be augmented with an implementation-defined | | | set of collations. | | | | | Default collation | The collation matched by | | | "http://www.iana.org/assignments/collation/ | | | default" (the actual collation is | | | implementation-defined) | | | | | Base URI | Unassigned. | | | | | Statically known | Initially unassigned. Overwriteable with | | documents | an implementation-defined value. | | | | | Statically known | Initially unassigned. Overwriteable with | | collections | an implementation-defined value. | | | | | Statically known | node()* | | default collection | | | type | | +---------------------+---------------------------------------------+ REQUIRED dynamic values +------------------+------------------------------------------------+ | Component | Specified Value | +------------------+------------------------------------------------+ | Function | Implementation-defined, MUST be consistent | | implementations | with function signatures. | | | | | Current dateTime | REQUIRED implementation-dependent value. | | | | | Implicit | REQUIRED implementation-defined value. | | timezone | | | | | | Available | Initially unassigned. Overwriteable with an | | documents | implementation-defined value. | | | | | Available | Initially unassigned. Overwriteable with an | | collections | implementation-defined value. | | | | | Default | Initially unassigned. Overwriteable with an | | collection | implementation-defined value. | +------------------+------------------------------------------------+ Godoy & Minni Expires July 16, 2008 [Page 9] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 2.2. Error and warnings This section describes the method by which XPath errors and warnings are reported. Error conditions are defined in [W3C.PR-xpath20-20061121], and warning conditions are OPTIONAL and implementation-defined. For conformance with [W3C.PR-xpath20-20061121], implementations MAY report any non-empty subset of errors. Additionally, if there is an error (other than a XPath error) that causes the request to be rejected, implementations MAY report the latter, with no mention to the XPath errors. The idref attributes of XS:xpath-error and XS:warning MAY be used to refer to the id attribute of the XS:xpath element whose content raised the error or warning. The mechanism that implementations use to return additional information is implementation-defined. 2.2.1. Warnings The XS:warning element contains at least one XML element, and MUST NOT contain text or mixed content. Children of the XS:warning element represent warnings signaled during the analysis of the expression. The DAV:multistatus and DAV:response elements, when used in response to XS:xml-search queries, are modified to include an OPTIONAL XS: warning element. Warnings raised during SAP apply to the whole query and are reported within the XS:warning element contained by DAV: multistatus. Warnings raised during DEP only apply to a particular resource and are reported within the DAV:response for that resource. The XS:xpath-error element MUST contain one or more elements describing the error. For instance, if an err:XPST0003 were raised (i.e. the XPath static error 0003: "a XPath expression is not a valid instance of the grammar") the response would be: HTTP/1.1 400 Bad Request Content-Type: text/xml; charset="utf-8" Content-Length: xxx (Note: the use of the "err:" prefix follows the convention of [W3C.PR-xpath20-20061121] but it is not normative.) 2.2.3. Errors (in DEP) An expression may be statically valid and raise an error under some dynamic conditions. Dynamic and type errors detected during DEP only invalidates the expression which raises them, when evaluated with the actual values of some resource property. A server MAY ignore errors detected in DEP if: -The error occurs within DAV:order, but that ordering criteria is not used (because other orders take precedence, or because the query matches one or no resource). -The error occurs within DAV:where part, and it does not affect the result. For instance, the error in (FALSE AND ERROR) may be omitted because the result would have been FALSE anyway, and the error in (TRUE OR ERROR) may be omitted because the result would have been TRUE anyway. If the error is not ignored, and the XPath expression was specified within the DAV:select part, it MAY be reported in the DAV:propstat element for the current property and resource. Otherwise it MAY be reported in the DAV:response element for the current resource. In both cases the status code 409 (Conflict) MUST be used. Godoy & Minni Expires July 16, 2008 [Page 11] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 Although errors in DEP depend on the value of the property, an error that is too frequent might have been caused by mistakes in the client's request. Therefore, instead of returning a sequence of DAV: response elements, all of which represent failures because of the same error, a server MAY report an error in DEP as a general failure invalidating the query itself, even if it is possible to evaluate other resources and properties. [error-DEP] When an error raised in DEP is reported as a general failure, the response will be marshaled as in Section 2.2.2, but the response status code MUST be 409 (Conflict) instead of 400 (Bad Request). For instance, if err:XPTY0004 were raised during DEP ("the dynamic type of a value does not match a required type"), the response would be: HTTP/1.1 409 Conflict Content-Type: text/xml; charset="utf-8" Content-Length: xxx the dynamic type of a value does not match a required type 2.3. Numeric Predicates "A step is a part of a path expression that generates a sequence of items and then filters the sequence by zero or more predicates." (Section 3.2.1 of [W3C.PR-xpath20-20061121]). A step expression may be either a FilterExpr or an AxisExpr. "A predicate consists of an expression, called a predicate expression, enclosed in square brackets. A predicate serves to filter a sequence, retaining some items and discarding others." (Section 3.2.2 of [W3C.PR-xpath20-20061121]) Support for numeric predicates and other references to the context position -e.g. by evaluating the fn:position() function- depends on the sequence where the predicate applies. Supporting numeric predicates in FilterExpr is OPTIONAL. If the step expression is an AxisStep, the requirement level depends on the specified axis. It is: Godoy & Minni Expires July 16, 2008 [Page 12] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 * NOT RECOMMENDED for the namespace and attribute axes, because the relative order of elements within these axes is implementation- dependent. * Always REQUIRED for the parent, self, and ancestor axes. * For the child, preceding-sibling and following-sibling axes: RECOMMENDED if the sequence order is semantically meaningful, OPTIONAL otherwise. * Always OPTIONAL for the descendant, descendant-or-self, ancestor- or-self, preceding, and following axes. [note-context-position] The way this feature is supported when it is not REQUIRED is implementation-dependent. 3. Discovery of the Query Grammar If a resource supports the SEARCH method, then the server MUST list SEARCH in the Allow header, as described in Section 3.1 of [I-D.reschke-webdav-search]. 3.1. The DASL Response Header The DASL response header indicates server support for a query grammar in the OPTIONS method. (Section 3.2 of [I-D.reschke-webdav-search]) The value of this header is a URI that indicates the type of grammar supported. Servers MUST return the following header when the OPTIONS method is invoked on any arbiter that supports the XS:xml-search grammar: DASL: 3.2. DAV:supported-query-grammar-set The WebDAV property DAV:supported-query-grammar-set is REQUIRED for any server supporting either [RFC3253] and/or [RFC3744] and identifies the XML based query grammars that are supported by the search arbiter resource (Section 3.3 of [I-D.reschke-webdav-search]). Servers implementing DAV:supported-query-grammar-set MUST report the following grammar for each arbiter resource supporting XS:xml-search: 3.3. Discovery of the XS:xml-search Query Schema Query Schema Discovery (QSD) is requested by means of the SEARCH Godoy & Minni Expires July 16, 2008 [Page 13] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 method, including an entity with a DAV:query-schema-discovery root element. As specified in Section 4.1 of [I-D.reschke-webdav-search], the response body takes the form of a DAV:multistatus element (Section 13 of [RFC4918]), where DAV:response is extended to hold the returned query grammar inside a DAV:query-schema container element. If the DAV:query-schema-discovery element contains XS:xml-search, then the response marshaling MUST be performed as described in this section and Section 5. Since the supported query grammars may depend on the scope, the XS: xml-search element (when used for QSD) MAY contain a DAV:from element. Other content is unexpected in this context. If several scopes are specified and the server supports multiple scopes, then the response MUST only contain those descriptions that are common to each scope. Request: SEARCH / HTTP/1.1 Host: host.example Content-Type: application/xml Content-Length: xxx Response: HTTP/1.1 207 Multistatus Content-Type: application/xml Content-Length: xxx http://host.example HTTP/1.1 200 OK Godoy & Minni Expires July 16, 2008 [Page 14] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 4. The XS:xml-search Grammar The elements used in XS:xml-search conform the semantics given in [I-D.reschke-webdav-search] for the DAV:basicsearch grammar, and all the operators defined in Section 5 of [I-D.reschke-webdav-search] (i.e. %all_ops;) are valid in the context of a XS:xml-search query. Additionally, some elements in the "DAV:" namespace are allowed to contain specific elements from the XS:xml-search grammar. Therefore, the semantics of a DAV:basicsearch valid query is preserved when the DAV:basicsearch content is submitted as a XS:xml- search query. This grammar also allows the additional element XS:filter as well as optional implementation-defined operators. The XS:filter element specifies an XPath expression (rooted on a single property, i.e. the root element is the property whose name is included in the DAV:prop element). It is both a query-operator and a special construct valid within DAV:select and DAV:order elements. //foo Godoy & Minni Expires July 16, 2008 [Page 17] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 If DAV:allprop is specified, it is understood as in a PROPFIND request [RFC4918]: (i.e., properties defined in RFC 4918, at a minimum, plus dead properties MUST be returned). Hence, the set of properties selected by allprop vary from resource to resource. If the request includes not only DAV:allprop but also one or more DAV:prop elements specifying properties which are already returned per DAV:allprop, or the request includes a property twice in DAV:prop elements, then the redundant properties MUST be ignored (i.e. a single property value will be returned). This behaviour is similar to that of the DAV:include element in a PROPFIND request (but DAV: include is not defined for XS:xml-search requests). There is no error when a property that would be returned per DAV: allprop is also specified within a XS:filter element (since the client may not be aware of the properties that will be returned when DAV:allprop is specified). This combination MUST be addressed as follows: - The XS:filter elements are processed as usual. This result in properties contained in DAV:propstat; elements with status code 200, 4xx or 5xx (as appropriate). - Each property that would have been returned per DAV:allprop in a PROPFIND request and was not included within a XS:filter element, is selected. 4.3. Query criteria The DAV:where element specifies optional query criteria. Only those resources that verify the query criteria are included in the result set. 4.3.1. DAV:prop operand The result of the DAV:prop operand is the value of the specified property of the resource being evaluated. If the property is a live one, the result datatype SHOULD be the actual property datatype. If the property is dead, or the server chooses to ignore the live property datatype, the result MUST be of type xs:string. Note: "A property name is a universally unique identifier that is associated with a schema that provides information about the syntax and semantics of the property." (Section 4.4 of [RFC4918]). Therefore, each property name SHOULD be permanently associated with at most one datatype. Godoy & Minni Expires July 16, 2008 [Page 18] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 4.3.2. Literal Operands DAV:literal and DAV:typed-literal allow literal values to be placed in an expression. When used with the operators defined in [I-D.reschke-webdav-search]: - The type of a DAV:literal value MUST be the type of the other operand in the expression. - The type of a DAV:typed-literal value MUST be the type specified in the xsi:type attribute, or xs:string if no type was specified. The value of the other operand MUST be casted to this type. A request with a DAV:typed-literal specifying an unknown type MUST be rejected by returning a response with status code 422 (Unprocessable Entity) and precondition code XS:known-literal-type. The xs:string type MUST NOT be unknown. 4.3.3. Relational operators The relational operators take a property and literal operand. XS: xml-search inherits the five relational operators defined in [I-D.reschke-webdav-search]: DAV:eq, DAV:lt, DAV:gt, DAV:lte and DAV: gte. For each property and pair of values being compared: - per Section 4.2.1 of [W3C.REC-xmlschema-2-20041028] the result of DAV:eq; is always defined, then DAV:eq; MUST NOT return NULL. - all of DAV:lt, DAV:gt, DAV:lte and DAV:gte MUST be either undefined or consistently defined. If they are defined, they MUST also conform the result of DAV:eq (i.e., A == B iff A<=B and A>=B). If the property type is known and it is a complex type, the result of these operations SHOULD be undefined. [note-comparison-complex-type] (Values within such properties may be compared by means of XPath predicates.) If the property type is known and it is a simple built-in ordered type, the order relation used in the comparison SHOULD be that defined in [W3C.REC-xmlschema-2-20041028]. If the property type is known and it is a simple type, an implementation-dependent order relation MAY be used. If a partial order is used, then trying to compare two values which are not comparable yields an undefined result. In any case, the collation algorithm is implementation-dependent. Other operators and operands retain the behaviours defined in Godoy & Minni Expires July 16, 2008 [Page 19] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 [I-D.reschke-webdav-search]. 4.3.4. The XS:filter operator When used inside a DAV:where element (or a sub-element thereof) XS: filter evaluates as: - TRUE if (and only if) the XPath expression matches at least one element, - FALSE if (and only if) no element within the property is matched, - NULL if (and only if) the property does not exist or its value is not a well-formed XML fragment. 4.3.5. The XS:is-well-formed operator The XS:is-well-formed operator takes a DAV:prop operand and returns: - TRUE if (and only if) the property value is a well formed XML fragment. - FALSE if (and only if) the property value is not a well formed XML fragment. - NULL if (and only if) the property does not exist. Supporting this operator is REQUIRED for properties which are XS: searchable, and OPTIONAL for properties which are only DAV: searchable. 4.4. Ordering DAV:orderby specifies a lexicographical order on the set of DAV: response to be returned. Comparisons are applied as they occur in the DAV:orderby element, earlier comparisons being more significant (Section 5.6 of [I-D.reschke-webdav-search]). When used within XS:xml-search, a DAV:orderby element MUST contain one or more DAV:order elements, which are allowed to contain a DAV: prop, a DAV:score or a XS:filter elements. When DAV:order contains a DAV:prop element, the ascending (alternatively, descending) order MUST be consistent with the comparison performed by DAV:lte (alternatively, DAV:gte): - If A<=B (alternatively, A>=B) according to DAV:lte, then A collates before B. - If A<=B (alternatively, A>=B) is undefined, then the collation order is implementation-dependent. When DAV:order contains a DAV:score element, an integer comparison is performed on each DAV:score value computed for the DAV:contains operation. Godoy & Minni Expires July 16, 2008 [Page 20] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 When DAV:order contains a XS:filter element, result-sets will be logically partitioned in three equivalence classes, based on the evaluation of XS:filter (as defined in Section 4.3). The equivalence classes are totally ordered (in ascending order) as: NULL < false < true. Ordering within each equivalence class (i.e. ordering among all the responses for which the XS:filter element evaluates to the same value) is implementation-dependent. (The order specified for the item-type in the sequence returned by the xpath expression MAY be used.) 4.5. SEARCH Status Codes for responses to XS:xml-search queries - 207 (Multistatus) The server accepted the request. The result set are returned within a DAV:multistatus; element. - 400 (Bad Request) Error in SAP, or the query includes both a plain DAV:prop and a XS:filter specifying the same property name. - 403 (Forbidden) The server rejected the request because the user has no privileges for performing queries under the specified arbiter resource. - 404 (Not found) The arbiter resource does not exist. - 409 (Conflict) Error in DEP (general failure) or invalid scope. - 422 (Unprocessable Entity) A property was specified in a role which is rejected for that property. An unknown type was specified in DAV:typed-literal. A required extension is not supported. Other status codes may be returned (redirections, client errors, server errors), with the meaning defined in [RFC2616]. The 207 status code MUST be used if and only if a result set is included in the response (an empty result set is allowed if the query does not match any resource). If the query could not be performed because of several errors, the error which is reported is implementation-dependent. If the client has no privileges for testing whether the arbiter exists then 403 (Forbidden) SHOULD be used instead of 404 (Not found). If the client has no privileges for accessing the specified scope then 409 (Conflict) MUST be returned 4.6. Status Codes for Use in 'response' Elements - 204 (No Content) if the resource exists and no selection list was specified (i.e. the DAV:select element is empty). Godoy & Minni Expires July 16, 2008 [Page 21] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 - 209 (Conflict) Error in DEP. The search was invalidated for resources identified by DAV:href elements in the response. If a selection list was specified, the response MUST NOT contain a DAV:status element, but a DAV:propstat listing the selected properties. If the client has no privileges for testing whether a resource exists, that resource MUST be silently omitted from the response. 5xx status codes MAY be used if a error occurs when accessing the resource. 4.7. Status Codes for Use in 'propstat' Elements - 200 (OK) for each selected property, if the property exists. - 403 (Forbidden) if the client has no privileges for accessing the selected property. - 404 (Not Found) for each property selected through DAV:allprop, DAV:prop or XS:filter if the property does not exist (OPTIONAL). - 409 (Conflict) if a property specified in a selection XS:filter element does not contains well-formed XML. The associated postcondition MUST be XS:property-must-be-well-formed-xml. If the client has no privileges for testing whether the property exists, the server SHOULD either omit the property or return a 404 (Not found) status code (instead of 403). 5xx status codes MAY be used if a error occurs when accessing the property value. 4.8. Precondition and postcondition Codes 4.8.1. XS:property-must-be-well-formed-xml Type: postcondition Use with: /multistatus/response/propstat/error, 409 Conflict Purpose: the actual property value does not contain a well-formed XML fragment, and the property was specified in a XS:filter element. 4.8.2. XS:acceptable-role Type: precondition Godoy & Minni Expires July 16, 2008 [Page 22] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 Use with: /error, 422 Unprocessable Entity Purpose: the XS:xml-search request includes a property for a role where it is not acceptable. 4.8.3. XS:XPath-error Type: precondition/postcondition Use with: /error, 400 Bad Request (precondition) /error, 409 Conflict (precondition) /multistatus/response/error, 409 Conflict (postcondition) /multistatus/response/propstat/error, 409 Conflict (postcondition) Purpose: The query includes an XPath expression that raises an error. (see Section 2.2.) 4.8.4. DAV:search-scope-valid Type: precondition Use with: /error, 409 Conflict Defined in [I-D.reschke-webdav-search] 4.8.5. XS:known-literal-type Type: precondition Use with: /error, 422 Unprocessable Entity Purpose: The query includes a DAV:typed-literal which specifies an unknown data-type. The data-type name is included into the element content. 5. Query Schema for XS:xml-search The query schema provides information about the set of available properties and implemented operators. Godoy & Minni Expires July 16, 2008 [Page 23] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 The query schema is marshaled within a XS:xml-search-schema element. This element contains an unordered set of property descriptions (DAV: propdesc) and operator description rules (XS:opdesc-rule). 5.1. Property descriptions The semantics of DAV:propdesc, when used within a XS:xml-search- schema is extended for describing whether a property may be used as root element of a XPath expression within a XS:filter element. Since XS:filter may appear in three different places (the record-set definition, the query criteria and the ordering criteria), the server may allow or disallow it on a separate basis. If XS:selectable, XS: searchable or XS:sortable is present, then the server MUST allow this property to be used within a XS:filter element in the applicable context (role) Properties which are XS:selectable or XS:searchable are also DAV: selectable or DAV:searchable respectively. For instance, if a property may be selected through a XPath expression then it is plainly selectable, and if a property may be used within a XS:filter query criterion then it may be used as an operand of DAV:is-defined, DAV:is-well-formed. Properties which are XS:sortable are not DAV:sortable, because comparison of complex types is undefined. Properties MUST NOT be DAV:sortable and XS:sortable at the same time. Godoy & Minni Expires July 16, 2008 [Page 24] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 The server MUST allow described properties to be used in the role for which they were advertised. This hint does not assert whether the property is defined on every resource in the scope, and does not assert whether the property value is well-formed XML. There SHOULD be one description for DAV:any-other-property. There MUST NOT be more than one description for each property, and one description for DAV:any-other-property. The "name" attribute of the XS:axis element specifies the name of an optional axis which is supported for the property being described. 5.2. Operator descriptions Operators are described in a way that borrows some elements from ABNF [RFC4234] (namely repetitions and alternatives). This approach allows a flexible and compact description of operators. [note-opdesc] 5.2.1. XS:opdesc-rule and XS:operator Godoy & Minni Expires July 16, 2008 [Page 25] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 XS:operator references the name of an operator. Several operators may be defined by the same XS:opdesc-rule, and several XS:opdesc-rule may define incremental alternatives (that is, an initial rule may match one or more alternatives, with later rule definitions adding to the set of alternatives, as in the ABNF construction Rule1 =/ Rule2 defined in section 3.3 of [RFC4234]). For instance, is equivalent to Mandatory operators SHOULD be omitted from the actual schema returned by a server (since their grammar is implied). If an operator is defined or enhanced by an extension of this protocol, the server MUST Godoy & Minni Expires July 16, 2008 [Page 26] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 return rules (i.e. one or more XS:opdesc-rule elements) for them. If the enhanced operator is a mandatory one, then the alternative rule applies. Hence, if the response includes it means that the DAV:eq operator accepts a pair of (property, foo: bar) operands, as well as it accepts the above-defined (property, literal) and (property, typed-literal) alternatives (from the implicit grammar). The order in which operands are described is significant, because the ordering of operands within a expression is significant. 5.2.2. XS:repetition The semantics of element XS:repetition is similar to the ABNF Variable Repetition (e.g: *Rule) defined in Section 3.6 of [RFC4234]. The optional attributes "atleast" and "atmost" indicates minimum and maximum allowed occurrences of the described content. Default values are atleast="0" and atmost="infinity" so that allows any number of occurrences, including zero; requires at least one, with no upper limit; allows exactly 3 and allows one or two. 5.2.3. XS:alternative The semantics of element XS:alternative is similar to the ABNF Alternatives (e.g: Rule1 / Rule2) defined in Section 3.2 of [RFC4234]. For instance, will accept either an operand- typed-literal or an operand-literal but not both. 5.2.4. Implied operator description The following query schema describes the operators specified in this document, as well as the operators from [I-D.reschke-webdav-search], as they would be reported in a QSD response. Godoy & Minni Expires July 16, 2008 [Page 27] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 This description is implied, i.e. servers SHOULD NOT include it in the response because these operators with these signatures are mandatory. Godoy & Minni Expires July 16, 2008 [Page 28] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 The DAV:is-collection operator is supported because XS:xml-search extends DAV:basicsearch grammar. It can be expressed by using XS: filter as: /collection Tests for other resource types, as well as test for no resource type may be expressed by the XS:filter operator (provided that DAV: resourcetype is XS:searchable). For instance, testing whether a resource has no resource type may be expressed as: count(/*)==0 5.2.5. Extended operator description for DAV:typed-literal Operand The DAV:eq, DAV:gt, DAV:lt, DAV:lte, and DAV:gte operators MAY accept a DAV:typed-literal operand, instead of DAV:literal. This alternative is not implied (i.e. if supported, it MUST be included in the QSD response). If DAV:typed-literal were supported (as defined in [I-D.reschke-webdav-search]), the QSD response would include the following rule: 5.2.5.1. Description of DAV:like Operator If the DAV:like operator is supported (as described in Section 5.2.2 of [I-D.reschke-webdav-search], the following rule MUST be included in the QSD: Godoy & Minni Expires July 16, 2008 [Page 29] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 6. XML Extensibility The extensibility mechanism from Section 17 of [RFC4918] (i.e., to process received XML documents as if unexpected elements and attributes, and all children of unrecognized elements, were not present) may be inappropriate when dealing with queries because they would not be evaluated as specified by the client (e.g. the query criteria may be loosen or the result record or may be incomplete). The omission of unexpected content might not be realized by the client. The extension attribute provides a mean for distinguishing whether the extension was recognized or ignored, raising a precondition error in the latter case. The attribute value MUST be either "required" or "optional". For conformance with [RFC4918] and Section 5.2.2 of [I-D.reschke-webdav-search], when this attribute is not specified its value defaults to "required" when the element occurs as a descendant of DAV:where, and "optional" anywhere else. Any element allows the following attributes (where "..." represents the element type name): When an unexpected or unknown element is present in the request, the server MUST: - Ignore it (and its descendants), if the value of the "extension" attribute for that element is "optional" (or the "extension" attribute is missing and the element is not a descendant of DAV: where). The request is then processed as if the element were not there. - Fail with status code 422 (Unprocessable Entity) and precondition code XS:unexpected-content, if the value of the "extension" attribute for that element is "required" (or if there is no "extension" attribute and the element is a descendant of DAV: where). In this case, the attrname attribute of XS:unexpected- content MUST NOT be specified. If the element has an "id" attribute, the idref attribute of the XS:unexpected-content precondition MUST be the element id, otherwise the "idref" attribute MUST NOT be specified. Godoy & Minni Expires July 16, 2008 [Page 30] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 When an unexpected or unknown attribute occurs within an expected element, the server MUST proceed as if the element itself were unexpected or unknown. In addition, if the element is required (as explained above), the attrname attribute of the XS:unexpected-content precondition MUST be assigned with the name of the offending attribute. If present, the idref attribute MUST match the value of some ID attribute in the request. 7. Security Considerations The security considerations of WebDAV SEARCH [I-D.reschke-webdav-search], and WebDAV [RFC4918], as well as those of HTTP/1.1 [RFC2616] and XML [RFC3023] are applicable to the WebDAV extension described in this document. 8. IANA Considerations This document defines XML elements in a XML namespace described by a URN conforming the registry mechanism described in [RFC3688]. The following URI assignment is requested URI: urn:ietf:params:xml:ns:webdav-xml-search Registrant Contact: See the "Author's Address" section of this document. XML: None. Namespace URIs do not represent an XML specification. Reference: The last version of this document. 9. References 9.1. Normative References [I-D.reschke-webdav-search] Reschke, J., "Web Distributed Authoring and Versioning (WebDAV) SEARCH", draft-reschke-webdav-search-14 (work in progress), November 2007. [RFC2119] Bradner, S., "Key words for use in Godoy & Minni Expires July 16, 2008 [Page 31] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media Types", RFC 3023, January 2001. [RFC3253] Clemm, G., Amsden, J., Ellison, T., Kaler, C., and J. Whitehead, "Versioning Extensions to WebDAV (Web Distributed Authoring and Versioning )", RFC 3253, March 2002. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. [RFC3744] Clemm, G., Reschke, J., Sedlar, E., and J. Whitehead, "Web Distributed Authoring and Versioning (WebDAV) Access Control Protocol", RFC 3744, May 2004. [RFC4790] Newman, C., Duerst, M., and A. Gulbrandsen, "Internet Application Protocol Collation Registry", RFC 4790, March 2007. [RFC4918] Dusseault, L., "HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)", RFC 4918, June 2007. [W3C.PR-xpath20-20061121] Berglund, A., Boag, S., Chamberlin, D., Fernandez, M., Kay, M., Robie, J., and J. Simeon, "XML Path Language (XPath) 2.0", World Wide Web Consortium PR PR-xpath20-20061121, November 2006, . [W3C.REC-xml-names11-20060816] Hollander, D., Layman, A., Tobin, R., Godoy & Minni Expires July 16, 2008 [Page 32] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 and T. Bray, "Namespaces in XML 1.1 (Second Edition)", World Wide Web Consortium Recommendation REC-xml- names11-20060816, August 2006, . [W3C.REC-xml11-20060816] Maler, E., Sperberg-McQueen, C., Cowan, J., Paoli, J., Bray, T., and F. Yergeau, "Extensible Markup Language (XML) 1.1 (Second Edition)", World Wide Web Consortium Recommendation REC-xml11-20060816, August 2006, . [W3C.REC-xmlschema-2-20041028] Malhotra, A. and P. Biron, "XML Schema Part 2: Datatypes Second Edition", World Wide Web Consortium R ecommendation REC-xmlschema-2- 20041028, October 2004, . 9.2. Informative References [RFC4234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 4234, October 2005. Editorial Comments [error-DEP] Besides, handling dynamic errors on a separate basis imposes an additional requirement, then supporting this feature is left to the criteria of implementors. [note-comparison-complex-type] This seems to be a MUST in [draft-reschke-webdav-search-14] Section 5.5.4, but is relaxed here since the property would be treated as xs:string if the type were ignored. [note-context-position] When supporting numeric predicates and context position references there Godoy & Minni Expires July 16, 2008 [Page 33] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 is a trade-off between expressive power and implementation costs. [note-intent] The authors' motivation for writing this specification is allowing metadata to be searchable when presented as a WebDAV property. Since it may be encoded as specified by a third-party schema, it should not be modified in order to conform WebDAV. [note-namespace] Since this protocol is experimental, the authors do not suggest new elements in order to not pollute the "DAV:" namespace. Thus, an experimental implementation of this protocol will not conflict with the following requirement from RFC 4918: "(...) an XML element in the "DAV:" namespace SHOULD NOT be used in the request or response body unless that XML element is explicitly defined in an IETF RFC reviewed by a WebDAV working group." [note-opdesc] The operator description is only intended for discovering whether the server implements an extension operator. The DAV:operators element from [I-D.reschke-webdav-search] is not adopted here, because it cannot describe the mandatory operators. On the other hand, while XML Schemas would have sufficed for this purpose, this approach would have required XS: xml-search clients to be in conformance to the XML Representation of Schemas, which is much more than necessary for achieving the above mentioned goal (given that the operators are not too complex). The chosen approach is compared to ABNF, in order to avoid further relation with features that are available in XML schemas. [note-OPTIONAL-404] The 404 status code for missing Godoy & Minni Expires July 16, 2008 [Page 34] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 properties is OPTIONAL in order to avoid an extensive response if the client selects several properties that are seldom defined. Note this behaviour is different from the PROPFIND case, where the 404 status code is REQUIRED for missing properties (Section 9.1 of [RFC 4918], page 35). [note-RFC4918-sect17] RFC4918: "(...) servers MUST process received XML documents as if unexpected elements and attributes (and all children of unrecognized elements) were not there" [note-select-prop-filter] If the property value is not well- formed XML specifying both DAV:prop and XS:filter is ambiguous because a 409 (Conflict) status code must be returned per XS:filter and the complete property value must be returned per DAV:prop. On the other hand, if the property value were well-formed XML, one of those elements would have to be ignored. Appendix A. Example XS:xml-search query This example shows a request/response exchange for selecting the DAV: getcontentlength property and the and first elements of the property, from resources which are directly contained in the http://host.example.com/ collection, such that the title (as described by a M:title element within the M:metadata property) starts with letter "S". The first results will have at least one M:author element present. The response describes two resources: - foo.pdf, with DAV:getcontentlength = 65536, author = "John Doe" and title = "Sample Title" - bar.txt, with DAV:getcontentlength = 1024, title = "Sample Anonymous Resource" and no author. Request: SEARCH / HTTP/1.1 Host: host.example.com Content-Type: application/xml Godoy & Minni Expires July 16, 2008 [Page 35] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 Content-Length: xxx http://host.example.com/ 1 starts-with(/M:title,'S') /M:author Response: HTTP/1.1 207 Multi-Status Content-Type: text/xml; charset="utf-8" Content-Length: xxx http://host.example.com/foo.pdf Godoy & Minni Expires July 16, 2008 [Page 36] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 65536 John Doe Sample title HTTP/1.1 200 OK http://host.example.com/bar.txt 1024 Sample Anonymous Resource HTTP/1.1 200 OK Index A Attribute attrname (XS:unexpected-content element) 31 extension 30 id 30 idref (XS:unexpected-content element) 31 D Dynamic Context 5 Dynamic Error 5 Dynamic Evaluation Phase (DEP) 5 E Element DAV:and 15 DAV:multistatus 10 DAV:not 15 DAV:or 15 DAV:order 15 DAV:propdesc 24 DAV:response 10 DAV:search-scope-valid 23 DAV:select 15 Godoy & Minni Expires July 16, 2008 [Page 37] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 DAV:where 15 XS:acceptable-role 22 XS:alternative 25 XS:filter 15 XS:is-well-formed 15 XS:known-literal-type 23 XS:opdesc-rule 25 XS:operand-nested-op 25 XS:operand-XPath 25 XS:operator 25 XS:property-must-be-well-formed-xml 22 XS:repetition 25 XS:searchable 24 XS:selectable 24 XS:sortable 24 XS:unexpected-content 31 XS:warning 10 XS:xml-search 15 XS:xml-search-schema 24 XS:XPath 15 XS:XPath-error 23 XS:xpath-error 11 Example Bad Request, DAV:select 17 DASL Response Header 13 DAV:supported-query-grammar-set 13 Description of DAV:like Operator 29 Extended operator description for DAV:typed-literal operand 29 Implied operator description 28 QSD request 14 QSD response 14 XS:opdesc-rule 26-27 XS:XPath-error (in DEP) 12 XS:XPath-error (in SAP) 11 I Implementation-defined 5 Implementation-dependent 5 R Role 5 S Static Analysis Phase (SAP) 5 Static Context 5 Static Error 6 T Godoy & Minni Expires July 16, 2008 [Page 38] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 Type Error 6 Authors' Addresses Roberto Javier Godoy Universidad Nacional del Litoral, Facultad de Ingenieria y Ciencias Hidricas, Departamento de Informatica Ciudad Universitaria, Ruta Nac. 168 S3001XAI, Paraje "El Pozo" Argentina EMail: rjgodoy@fich.unl.edu.ar Hugo Minni Universidad Nacional del Litoral, Facultad de Ingenieria y Ciencias Hidricas, Departamento de Informatica Ciudad Universitaria, Ruta Nac. 168 S3001XAI, Paraje "El Pozo" Argentina EMail: hminni@fich.unl.edu.ar Godoy & Minni Expires July 16, 2008 [Page 39] Internet-Draft WebDAV Search Grammar for XML Properties January 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). 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The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is currently provided by the IETF Administrative Support Activity (IASA). Godoy & Minni Expires July 16, 2008 [Page 40]