SIMPLE WG J. Urpalainen Internet-Draft Nokia Research Center Expires: September 7, 2006 March 6, 2006 An Extensible Markup Language (XML) Patch Operations Framework Utilizing XML Path Language (XPath) Selectors draft-ietf-simple-xml-patch-ops-02 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 September 7, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract Extensible Markup Language (XML) documents are widely used as containers for the exchange and storage of arbitrary data in today's systems. Updates to this data require transporting of the entire XML document between hosts, unless there's a mechanism that allows exchanging only the updates of XML documents. This document describes an XML patch framework utilizing XML Path language (XPath) selectors. These selector values and updated new data content constitute the basis of patch operations described in this document. Urpalainen Expires September 7, 2006 [Page 1] Internet-Draft Patch Operations March 2006 In addition to them, with basic , and directives a set of patches can then be applied to update an existing XML document. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Basic Features and Requirements . . . . . . . . . . . . . . . 4 4. Patch Operations . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. Locating the Target for a Patch . . . . . . . . . . . . . 6 4.2. Namespace Mangling . . . . . . . . . . . . . . . . . . . . 6 4.3. Element . . . . . . . . . . . . . . . . . . . . . . 8 4.4. Element . . . . . . . . . . . . . . . . . . . . 11 4.5. Element . . . . . . . . . . . . . . . . . . . . . 12 5. Error Handling . . . . . . . . . . . . . . . . . . . . . . . . 14 6. Usage of Patch Operations . . . . . . . . . . . . . . . . . . 14 7. Usage of Selector Values . . . . . . . . . . . . . . . . . . . 14 8. Full Example . . . . . . . . . . . . . . . . . . . . . . . . . 14 9. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 16 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 10.1. XML Schema Registration . . . . . . . . . . . . . . . . . 18 11. Security Considerations . . . . . . . . . . . . . . . . . . . 18 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19 13.1. Normative References . . . . . . . . . . . . . . . . . . . 19 13.2. Informative References . . . . . . . . . . . . . . . . . . 20 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 21 Intellectual Property and Copyright Statements . . . . . . . . . . 22 Urpalainen Expires September 7, 2006 [Page 2] Internet-Draft Patch Operations March 2006 1. Introduction Extensible Markup Language (XML) [2] documents are widely used as containers for the exchange and storage of arbitrary data in today's systems. An example of such a system is the Common Presence Profile (CPP) [16] compatible presence system, in which presence data is represented using the XML based Presence Information Data Format (PIDF) [17]. Updates to this data require transporting of the entire XML document between hosts, unless there's a mechanism that allows exchanging only the updates of an XML document. This document describes an XML patch framework which utilizes XML Path language (XPath) [3] selectors. An XPath selector is used to pinpoint the target for a change. These selector values and updated new data content constitute the basis of patch operations described in this document. In addition to them, with basic , and directives a set of patches can be applied to update an existing initial XML document. With these patch operations, a simple semantics for data oriented XML documents [7] is achieved, that is, modifications like additions, removals or substitutions of elements and attributes can easily be performed. This document does not describe a full XML diff format, only basic patch operation elements which can be embedded within a full format. As an example, in the Session Initiation Protocol (SIP) [18] based presence system a partial PIDF XML document format [13] consists of the existing PIDF document format combined with the patch operations elements described in this document. In general, patch operations can be used in any application that exchanges XML documents, for example within the SIP Events framework [12]. Another example is XCAP-diff [14] which uses this framework for sending partial updates of changes to XCAP [15] resources. 2. Conventions In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119, BCP 14 [1] and indicate requirement levels for compliant implementations. The following terms are used in this document: Initial XML document: An initial XML document that is going to be updated with a set of patches. Urpalainen Expires September 7, 2006 [Page 3] Internet-Draft Patch Operations March 2006 XML diff document: A frame XML document that contains patch operation elements, namespace declarations and all the document content changes that are needed in order to transform an initial XML document into a new patched XML document. Patched XML document: An XML document that results after applying one or more patch operations defined in the XML diff document to the initial XML document. Patch operation: A single change, i.e. a patch that is being applied to update an initial XML document. Patch operation element: An XML element that represents a single patch operation. Type definition for an element: A W3C Schema type definition for an element that describes a patch operation content. In-scope namespace declaration: A list of all in-scope namespace declarations within a context node. The QName expansion of a context node is based on mapping a prefix with one of these declarations. For an element, one namespace binding may have an empty prefix. Positional constraint: A number enclosed with square brackets. It can be used as a location step predicate. Located target node: A node which was found from the initial XML document with the aid of an XPath selector value. White space text node: A text node which contains only white space. 3. Basic Features and Requirements In this framework, XPath selector values and new data content are embedded within XML elements, the names of which imply the type of a modification: , or . These elements, or synonymously patch operations as used in this document, are described by defining their schema types with the W3C Schema language [6]. XPath selectors pinpoint the target for a change and they are expressed as attributes of these elements. The child node(s) of patch operation elements contain the new data content. In general when applicable, the new content SHOULD be moved unaltered to the patched XML document. The specifications utilizing these element types MUST define the full XML diff format with an appropriate MIME type [11] and a character Urpalainen Expires September 7, 2006 [Page 4] Internet-Draft Patch Operations March 2006 set, e.g. UTF-8 [9]. The partial PIDF format [13] includes this schema and describes additional definitions to produce a complete XML diff format for partial presence information updates. As the schema defined in this document does not declare any target namespace, the type definitions inherit the target namespace of the including schema. Therefore, additional namespace declarations within the XML diff documents can be avoided. It is anticipated that applications using these types will define , and elements based on the corresponding type definitions in this schema. In addition, an application may reference only a subset of these type definitions. A future extension can introduce other operations, e.g. with document oriented models [7] a operation and a text node patching algorithm combined with would undoubtedly produce smaller XML diff documents. The instance document elements based on these schema type definitions MUST be well formed and SHOULD be valid. The following XPath 1.0 data model node types can be added, replaced or removed with this framework: elements, attributes, namespaces, comments, texts and processing instructions. The full XML prolog including e.g. XML entities [2] and the root node of an XML document cannot be patched according to this framework. However, patching of comments and processing instructions of the root node is allowed. Naturally the removal or addition of a document root element is not allowed as any valid XML document MUST always contain a single root element. Also note that support for external entities is beyond the scope of this framework. Note: Implementations must thus be based on XML parsers and XPath interpreters that support all XPath 1.0 data model node types except the root node of an XML document. In addition to the location capability of these nodes, some application programming interfaces are needed for their manipulation in practice. XML documents which are equivalent for the purposes of many applications MAY differ in their physical representation. The aim of this document is to describe a deterministic framework where the canonical form with comments [4] of an XML document determines logical equivalence. For example, white space text nodes MUST be processed properly in order to fulfil this requirement as white space is by default significant [4]. Urpalainen Expires September 7, 2006 [Page 5] Internet-Draft Patch Operations March 2006 4. Patch Operations An XML diff document contains a collection of patch operation elements, including one or more , and elements. These patch operations will be applied sequentially in the document order. After the first patch has been applied to update an initial XML document, the patched XML document becomes a new initial XML document. This procedure repeats until all patches have successfully been processed. In other words, this framework does not allow "apply all occurrences" in one pass. 4.1. Locating the Target for a Patch Each patch operation element contains a 'sel' attribute. The value of this attribute is an XPath selector with a restricted subset of the full XPath 1.0 recommendation. The 'sel' value is used to locate a single unique target node from the initial XML document. This located node pinpoints the target for a change and usually it is an element, which is e.g. either updated itself or some child node(s) are added into it. It may also be for instance a comment node, after which some other sibling node(s) are inserted. In any case, it is an error condition if multiple nodes are found during the evaluation of this selector value. The XPath selections of the 'sel' attribute always start from the root node of a document. Thus relative location paths SHOULD be used so that the starting root node selection "/" can be omitted. When locating elements in a document tree, a node test can either be a "*" character or a QName. A "*" character selects all element children of the context node. Right after the node test, a location step can contain one or more predicates in any order. An attribute value comparison is one of the most typical predicates. The string value of the current context node or a child element may alternatively be used to identify elements in the tree. The character ".", which denotes a current context node selection, is an abbreviated form of "self::node()". Lastly, positional constraints like "[2]" can also be used as an additional predicate. An XPath 1.0 "id()" node-set function MAY also be used to identify unique elements from the document tree. The schema that describes the content model of the document MUST then use an attribute with the type ID [7] or with non-validating XML parsers, an "xml:id" [8] attribute MUST have been used within an instance document. 4.2. Namespace Mangling While the XPath recommendation specifies that prefixes can be used in location steps, it does not specify how associated namespace URIs are Urpalainen Expires September 7, 2006 [Page 6] Internet-Draft Patch Operations March 2006 discovered during these evaluations. In the patch operation framework QName [5] expansion within a location step is evaluated according to the namespace declarations of the XML diff document. Thus the namespace URIs for these prefixes are found from the in- scope namespaces of the patch operation element. In other words, the XML diff document contains all needed information for QName expansions in order to perform XPath searches from the initial XML document. Note: It should be emphasized that prefixes within the XPath selectors MAY be different than those of the initial XML document because the matching of nodes is based on expanded names, i.e. a prefix maps to a namespace URI and these URIs and local names MUST be identical. For example, with a selector "p:foo", "p" maps to a namespace URI and "foo" is the local name. In this framework, when a node test is "foo" and the patch operation element has an in-scope default namespace declaration, a qualified element from the initial XML document is being searched. That is, the namespace URI of the expanded name of the located element MUST then be identical compared to this default namespace declaration. If there's not an in-scope default namespace declaration within the evaluation context, an unqualified element is located. Note: By contrast, in XPath 1.0 a "foo" selector always locates an unqualified element but in XPath 2.0 [10] also a qualified one which is attached with the default namespace declaration. Note: The XPath 1.0 recommendation specifies "namespace-uri()" and "local-name()" node-set functions which can be used within predicates. These functions may be utilized during XPath evaluations if there are no other means to "register" prefixes with associated namespace URIs. They can also be used when handling selections where default namespaces are attached to elements. However, the schema type definitions for these patch operation elements do not allow the usage of these functions. Also elements within the changed data content are usually namespace qualified. For example, when adding a new namespace qualified element to the initial XML document, the namespace declaration reference of this new element belongs first to the XML diff document. Naturally after copying or moving this element, the attached namespace MUST refer to a declaration within the patched XML document. If this namespace is declared in the patch operation element or within its ascendants, these references MUST thus be changed. Like in XPath, the mapping of these references is based on identical namespace URIs, not prefixes. The namespace with an Urpalainen Expires September 7, 2006 [Page 7] Internet-Draft Patch Operations March 2006 identical URI from the in-scope namespaces of a context node of the initial XML document MUST be chosen. However, if overlapping in- scope namespaces exist, i.e., there are several in-scope namespaces with an identical namespace URI, then the namespace with the same prefix MUST be chosen. If an equivalent prefix is not then found, an error occurs. For instance, this kind of overlapping can happen when a namespace qualified attribute is added while elements are attached with an identical default namespace declaration. When the new added or updated elements contain namespace declarations, the namespace nodes move unaltered from the XML diff document to the patched XML document. Default namespace declarations can only be added by this way but prefixed namespace declarations MAY be added or removed with XPath namespace axis semantics shown later in this document. Note: In practice, this namespace mangling means that an XML diff document MUST only know the namespace URIs of qualified nodes, the prefixes of the initial XML document are not significant unless there are those overlapping namespace declarations. In other words, regardless whether the prefixes of qualified elements of the initial XML document are empty (default namespace attached) or not, the XML diff document may remain the same. 4.3. Element The element represents the addition of some new content to the initial XML document: e.g. a new element can be appended into an existing element. The new data content exists as the child node(s) of the element. When adding attributes and namespaces the child node of the element MUST be a single text node. Otherwise, the element can contain any mixture of element, text, comment or processing instruction nodes in any order. All children of the element are then copied into an initial XML document. The described namespace mangling procedure applies to added elements, which include all of their attribute, namespace and descendant nodes. The element type has three attributes: 'sel', 'type' and 'pos'. The value of the optional 'type' attribute is only used when adding attributes and namespaces. Then the located target node MUST be an element into which new attributes and namespace declarations are inserted. When the value of this 'type' attribute equals "@attr" the purpose is to add a new attribute node with the name 'attr'. The value of this new 'attr' attribute is the text node content of the element. The less frequently used, prefixed, i.e. namespace Urpalainen Expires September 7, 2006 [Page 8] Internet-Draft Patch Operations March 2006 qualified attributes can also be added. If the value of the 'type' attribute equals "namespace::pref" the aim is to add a new "pref" prefixed namespace declaration and the text node content of the element contains the corresponding namespace URI. Note: The 'type' attribute is thus also an XPath selector, but it only locates attributes and namespaces. Attribute axis "attribute" has an abbreviated form "@" unlike the "namespace" axis which doesn't have an abbreviated form. Double colons "::" are used as an axis separator in XPath. The value of the optional 'pos' attribute indicates the positioning of new data content. It is not used when adding attributes or namespaces. When neither 'type' nor 'pos' attribute exist, the children of the element are then appended as the last child node(s) of the located target element. When the value of 'pos' attribute is "prepend" the new node(s) are added as the first child node(s) of the located target element. With the value of "before" the added new node(s) MUST be the immediate preceding sibling node(s) and with "after" the immediate following sibling node(s) of the located target node. Some examples follow where nodes are not namespace qualified and prefixes are therefore not used. The whole XML diff content is not shown in these examples, only patch operation elements because of simplicity reasons: This is a new child Once the element has been found from the initial XML document, a new element is appended as the last child node of the element. The located target node: the element is naturally the root element of the initial XML document. The new element contains an 'id' attribute and a child text node. An example for an addition of an attribute: Bob This operation adds a new 'user' attribute to the element which was located by using an 'id' attribute value predicate. The value of this new 'user' attribute is "Bob". A similar patched XML document is achieved when using a validating XML parser, if the 'sel' selector value had been 'id("ert4773")' and if the data type of the 'id' attribute is "ID" [7]. Urpalainen Expires September 7, 2006 [Page 9] Internet-Draft Patch Operations March 2006 Note: As the 'sel' selector value MAY contain quotation marks, escaped forms: """ or "'" can be used within attribute values. However, it is often more appropriate to use the apostrophe (') character as shown in these examples. An alternative is also to interchange the apostrophes and quotation marks. An example for an addition of a prefixed namespace declaration: urn:ns:xxx This operation adds a new namespace declaration to the element. The prefix of this new namespace node is thus "pref" and the namespace URI is "urn:ns:xxx". An example for an addition of a comment node: This operation adds a new comment node just before the element as an immediate preceding sibling node. This is also an example how a 'pos' attribute directive can be used. Some complexity arises when so called white space text nodes exist within an initial XML document. The XPath 1.0 data model requires that a text node MUST not have another text node as an immediate sibling node. For instance, if an add operation is like this: This is a new child The element has then two child nodes: a white space text node (a linefeed and two spaces) and a element. If the existing last child of the element is a text node, its content and the white space text node content MUST then be combined together. Otherwise (white space) text nodes can be added just like elements and thus, the canonical form of the patched XML document easily remains deterministic. As several sibling nodes can be inserted with a single operation, a "pretty printing" style can easily be maintained. Still another example about the handling of text nodes. Consider this example: newelem The second text node child of the element is first located. The added new content contains two text nodes and an element. As Urpalainen Expires September 7, 2006 [Page 10] Internet-Draft Patch Operations March 2006 there can not be immediate sibling text nodes, the located target text node content and the first new text node content MUST be combined together. In essence, if the 'pos' value had been "before", the second new text node content would effectively have been prepended to the located target text node. Note: It is still worth noting that text nodes MAY contain CDATA sections, the latter of which are not treated as separate nodes. Once these CDATA sections exist within the new text nodes, they SHOULD be moved unaltered to the patched XML document. While XML entities [2] cannot be patched with this framework, the references to other than predefined internal entities can exist within text nodes or attributes when the XML prolog contains those declarations. These references may then be preserved if both the XML diff and the initial XML document have identical declarations within their prologs. Otherwise, references may be replaced with identical text as long as the "canonically equivalent" rule is obeyed. 4.4. Element The element represents a replacement operation: e.g. an existing element is updated with a new element or an attribute value is replaced with a new value. This operation always updates a single node or node content at a time. The element type has only a 'sel' attribute. If the located target node is an element, a comment or a processing instruction, then the child of the element MUST also be of the same type. Otherwise the element MUST have text content or it MAY be empty when replacing an attribute value or a text node content. Examples for replace operations, first a replacement of an element: This will update the element which has an 'a' attribute with value "1". The located target element is replaced with the element. So all descendant nodes, namespace declarations and attributes of the replaced element, if any existed, are thus removed. An example for a replacement of an attribute value: new value This will replace the 'a' attribute content of the element with Urpalainen Expires September 7, 2006 [Page 11] Internet-Draft Patch Operations March 2006 the value "new value". If the element is empty, the 'a' attribute MUST then remain in the patched XML document appearing like . An example for a replacement of a namespace URI: urn:new:xxx This will replace the URI value of 'pref' prefixed namespace node with "urn:new:xxx". The parent node of the namespace declaration MUST be the element, otherwise an error occurs. An example for a replacement of a comment node: This will replace a comment node. The located target node is the first comment node child of the element. An example for a replacement of a processing instruction node: This will replace the processing instruction node "test" whose parent is the element. An example for a replacement of a text node: This is the new text content This will replace the first text node child of the element. The positional constraint "[1]" is not usually needed as the element content is rarely of mixed type [6] where several text node siblings typically exist. If a text node is updated and the element is empty, the text node MUST thus be removed as a text node MUST always have at least one character of data. 4.5. Element The element represents a removal operation of e.g. an existing element or an attribute. The element type has two attributes: 'sel' and 'ws'. The Urpalainen Expires September 7, 2006 [Page 12] Internet-Draft Patch Operations March 2006 value of the optional 'ws' attribute is used to remove the possible white space text nodes that exist either as immediate following or preceding sibling nodes of the located target node. The usage of 'ws' attribute is only allowed when removing other types than text, attribute and namespace nodes. If the value of 'ws' is "before", the purpose is to remove the immediate preceding sibling node which MUST be a white space text node and if the value is "after", the corresponding following node. If the 'ws' value is "both", both the preceding and following white space text nodes MUST be removed. Examples for remove operations, first a removal of an element including all of its descendant, attribute and namespace nodes: This will remove the element as well as the immediate following sibling white space text node of the element. If the immediate following sibling node is not a white space text node, an error occurs. An example for a removal of an attribute node: This will remove the 'a' attribute node from the element. An example for a removal of a namespace node: This will remove the 'pref' prefixed namespace node from the element. Naturally this prefix MUST not be associated with any node prior to the removal of this namespace node. Also the parent node of this namespace declaration MUST be the element. An example for a removal of a comment node: This will remove the first comment node child of the element. An example for a removal of a processing instruction node: This will remove the "test" processing instruction node child of the element. Urpalainen Expires September 7, 2006 [Page 13] Internet-Draft Patch Operations March 2006 An example for a removal of a text node: This will remove the first text node child of the element. When removing an element, a comment or a processing instruction node which has immediate preceding and following sibling text nodes without the 'ws' directive, the content of these two text nodes MUST be combined together. The latter text node thus disappears from the document. 5. Error Handling It is an error condition if any of the patch operations can not be unambiguously fulfilled. In other words, once a particular patch operation fails, it is an error condition and processing of further patch operations is hardly sensible. Also it is beyond the scope of this document to describe a generic error response. 6. Usage of Patch Operations An XML diff document SHOULD contain only the nodes which have been modified. However, when there's a large collection of changes it MAY be desirable to exchange the full document content instead. How this will be done in practice is beyond the scope of this document. 7. Usage of Selector Values It is up to the application to decide the verbosity model for selector values. Positional element selectors like "*/*[3]/*[2]" provide the shortest selectors, but care must to taken when using them. When there are several removals of sibling elements, the positional element indexes change after each update. Likewise these indexes change when new elements are inserted into the tree. Using names with possible attribute predicates like "doc[@sel='foo']" is usually easier for an application, be it e.g. an auto diff tool but it leads to larger diff documents. 8. Full Example An example initial XML document where namespace qualified elements exist: Urpalainen Expires September 7, 2006 [Page 14] Internet-Draft Patch Operations March 2006 This is a sample document An imaginary XML diff document where prefix "p" corresponds the targetNamespace of this imaginary schema: Patched doc new attr One possible form of the result XML document after applying the patches: Urpalainen Expires September 7, 2006 [Page 15] Internet-Draft Patch Operations March 2006 Patched doc The and removed element prefixes within the XML diff document are different than what are the "identical" namespace declarations in the initial XML document. If the initial XML document had used a prefixed namespace declaration instead of the default one, the XML diff document could still have been the same. The added new qualified elements would just have inherited that prefix. 9. XML Schema The schema types for the patch operation elements. ]> Urpalainen Expires September 7, 2006 [Page 16] Internet-Draft Patch Operations March 2006 Urpalainen Expires September 7, 2006 [Page 17] Internet-Draft Patch Operations March 2006 10. IANA Considerations 10.1. XML Schema Registration This section registers a new XML Schema. URI: urn:ietf:params:xml:schema:xml-patch-ops Registrant Contact: IETF, SIMPLE working group, Jari Urpalainen, 11. Security Considerations Information exchanged within these patch operations can be highly sensitive. Thus systems need to protect the integrity and Urpalainen Expires September 7, 2006 [Page 18] Internet-Draft Patch Operations March 2006 confidentiality of this data. Especially, the transport protocol once it is used SHOULD have capabilities to protect from possible threats. For example, a malicious man-in-the-middle attack could easily give misinformation. However, all the security considerations depend very much on the application which utilizes this framework. 12. Acknowledgments The author would like to thank Eva Leppanen, Mikko Lonnfors, Aki Niemi, Jonathan Rosenberg, Miguel A. Garcia, Anat Angel and Stephane Bortzmeyer for their valuable comments and Ted Hardie for his input and support. 13. References 13.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] "Extensible Markup Language (XML) 1.0 (Third Edition)", W3C Recommendation REC-xml-20040204 , February 2004. [3] "XML Path Language (XPath) Version 1.0", W3C Recommendation REC- xpath-19991116 , November 1999. [4] "Canonical XML 1.0", W3C Recommendation REC-xml-c14n-20010315 , March 2001. [5] "Namespaces in XML", W3C Recommendation REC-xml-names-19990114 , January 1999. [6] "XML Schema Part 1: Structures Second Edition", W3C Recommendation REC-xmlschema-1-20041028 , October 2004. [7] "XML Schema Part 2: Datatypes Second Edition", W3C Recommendation PER-xmlschema-2-20040318 , October 2004. [8] "xml:id Version 1.0 W3C Recommendation 9 September 2005", W3C Recommendation PR-xml-id-20050712 , September 2005. [9] Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC 2279, January 1998. Urpalainen Expires September 7, 2006 [Page 19] Internet-Draft Patch Operations March 2006 13.2. Informative References [10] "XML Path Language (XPath) Version 2.0", W3C Candidate Recommendation 3 20051103 , November 2005. [11] Murata, M., "XML media types", RFC 3023, January 2001. [12] Roach, A., "Session Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002. [13] Lonnfors, M., Leppanen, E., Khartabil, H., and J. Urpalainen, "Presence Information Data format (PIDF) Extension for Partial Presence", draft-ietf-simple-partial-pidf-format-06 (work in progress), March 2006. [14] Rosenberg, J., "An Extensible Markup Language (XML) Document Format For Indicating Changes in XML Configuration Access Protocol (XCAP) Resources", draft-ietf-simple-xcap-diff-0x (work in progress), ? 2006. [15] Rosenberg, J., "The Extensible Markup Language (XML) Configuration Access Protocol (XCAP)", draft-ietf-simple-xcap-08, October 2005. [16] Peterson, J., "Common Profile for Presence (CPP)", RFC 3859, August 2004. [17] Sugano, H., "CPIM presence information data format", RFC 3863, May 2003. [18] Niemi, A., "Session Initiation Protocol (SIP) Extension for Event State Publication", RFC 3903, October 2004. Urpalainen Expires September 7, 2006 [Page 20] Internet-Draft Patch Operations March 2006 Author's Address Jari Urpalainen Nokia Research Center Itamerenkatu 11-13 Helsinki 00180 Finland Phone: +358 7180 37686 Email: jari.urpalainen@nokia.com Urpalainen Expires September 7, 2006 [Page 21] Internet-Draft Patch Operations March 2006 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. 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. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Urpalainen Expires September 7, 2006 [Page 22]