Network Working Group C. Daboo Internet-Draft Apple, Inc. Intended status: Standards Track M. Douglass Expires: December 6, 2009 RPI S. Lees Microsoft June 4, 2009 iCalendar XML Representation draft-daboo-et-al-icalendar-in-xml-00 Status of This Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and 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 December 6, 2009. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Daboo, et al. Expires December 6, 2009 [Page 1] Internet-Draft iCalendar in XML June 2009 Abstract This specification defines a format for representing iCalendar data in XML. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions Used in This Document . . . . . . . . . . . . . . 3 3. Converting from iCalendar to XML . . . . . . . . . . . . . . . 4 3.1. Pre-processing . . . . . . . . . . . . . . . . . . . . . . 4 3.2. iCalendar stream (2445bis section 3.4) . . . . . . . . . . 4 3.3. Components (2445bis section 3.6) . . . . . . . . . . . . . 6 3.4. Properties (2445bis section 3.5) . . . . . . . . . . . . . 6 3.4.1. Special Cases for Properties . . . . . . . . . . . . . 8 3.4.1.1. Multi-valued Properties . . . . . . . . . . . . . 8 3.4.1.2. GEO Property . . . . . . . . . . . . . . . . . . . 9 3.4.1.3. REQUEST-STATUS Property . . . . . . . . . . . . . 9 3.5. Parameters (2445bis section 3.4) . . . . . . . . . . . . . 9 3.5.1. VALUE parameter . . . . . . . . . . . . . . . . . . . 10 3.6. Values (2445bis section 3.3) . . . . . . . . . . . . . . . 11 3.6.1. Binary (2445bis section 4.3.1) . . . . . . . . . . . . 11 3.6.2. Boolean (2445bis section 4.3.2) . . . . . . . . . . . 11 3.6.3. Calendar User Address (2445bis section 4.3.3) . . . . 11 3.6.4. Date (2445bis section 4.3.4) . . . . . . . . . . . . . 11 3.6.5. Date-Time (2445bis section 4.3.5) . . . . . . . . . . 12 3.6.6. Duration (2445bis section 4.3.6) . . . . . . . . . . . 12 3.6.7. Float (2445bis section 4.3.7) . . . . . . . . . . . . 12 3.6.8. Integer (2445bis section 4.3.8) . . . . . . . . . . . 12 3.6.9. Period of Time (2445bis section 4.3.9) . . . . . . . . 13 3.6.10. Recurrence Rule (2445bis section 4.3.10) . . . . . . . 13 3.6.11. Text (2445bis section 4.3.11) . . . . . . . . . . . . 13 3.6.12. Time (2445bis section 4.3.12) . . . . . . . . . . . . 13 3.6.13. URI (2445bis section 4.3.13) . . . . . . . . . . . . . 13 3.6.14. UTC Offset (2445bis section 4.3.14) . . . . . . . . . 13 3.7. Extensions . . . . . . . . . . . . . . . . . . . . . . . . 14 4. Converting from XML into iCalendar . . . . . . . . . . . . . . 14 5. Security Considerations . . . . . . . . . . . . . . . . . . . 14 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 6.1. Namespace Registration . . . . . . . . . . . . . . . . . . 14 6.2. Media Type . . . . . . . . . . . . . . . . . . . . . . . . 15 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16 8. Normative References . . . . . . . . . . . . . . . . . . . . . 16 Appendix A. Relax NG Schema . . . . . . . . . . . . . . . . . . . 16 Appendix B. XML Stylesheet for conversion to iCalendar . . . . . 40 Appendix C. Example . . . . . . . . . . . . . . . . . . . . . . . 40 C.1. iCalendar Data . . . . . . . . . . . . . . . . . . . . . . 40 C.2. XML Data . . . . . . . . . . . . . . . . . . . . . . . . . 41 Daboo, et al. Expires December 6, 2009 [Page 2] Internet-Draft iCalendar in XML June 2009 1. Introduction The iCalendar data format [I-D.ietf-calsify-rfc2445bis] is a widely deployed interchange format for calendaring and scheduling data. While many applications and services consume and generate calendar data, iCalendar is a specialized format that requires its own parser/ generator. In contrast, XML-based formats are widely used for interoperability between applications, and the many tools that generate, parse, and manipulate XML make it easier to work with than iCalendar. The purpose of this specification is to define an XML format that allows iCalendar data to be converted to XML, and then back to iCalendar, without losing any semantic meaning in the data. Anyone creating XML calendar data according to this specification will know that their data can be converted to a valid iCalendar representation as well. Several key design decisions have been made: Round-tripping: i.e., converting an iCalendar instance to XML and back will give the same result as the starting point. Make the conversion process as simple as possible. Make it easy to work with the XML without needing to re-parse it. It is worth explaining the rationale behind this decision. One result is that this specification breaks up date/time values from iCalendar into separate year, month, day, hour, minute, and second elements. By separating the values into different elements, it becomes much easier to transform or query over the resulting XML. For instance, given a set of xCal elements representing events, it is easy to find the events that start at a particular time or in a particular year, month, or day. Given a date / time value in the xCal format described here, it would be easy to transform it to HTML while removing unneeded sub-elements; no additional parsing is needed. Preserve the semantics of the iCalendar data. This decision is important: the semantics of iCalendar is preserved in the XML so a full understanding of iCalendar is required in order to actually use the data, whether it be in the iCalendar or XML formats. 2. Conventions Used in This Document 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]. Daboo, et al. Expires December 6, 2009 [Page 3] Internet-Draft iCalendar in XML June 2009 When XML element types in the namespace "urn:ietf:params:xml:ns:icalendar" are referenced in this document outside of the context of an XML fragment, the string "ICAL:" will be prefixed to the element types. Some examples in this document contain "partial" XML documents used for illustrative purposes. In these examples, three periods "..." are used to indicate a portion of the document that has been removed for compactness. 3. Converting from iCalendar to XML This section describes how iCalendar data is converted to XML using a simple, predictable mapping between the iCalendar data model and XML elements. 3.1. Pre-processing iCalendar data uses a line folding mechanism to limit lines of data to a maximum line length (typically 72 characters) to ensure maximum likelihood of preserving data integrity as it is transported via various means (e.g., email) - see Section 3.1 of [I-D.ietf-calsify-rfc2445bis]. Prior to converting iCalendar data into XML all folded lines MUST be unfolded. iCalendar data uses an "escape" character sequence for text values and parameter values. When such text elements are converted into XML the escaping MUST be removed. iCalendar uses a base64 encoding for binary data. The base64 encoding MUST remain when converted to XML. 3.2. iCalendar stream (2445bis section 3.4) iCalendar has a well defined object model for its data that makes mapping to XML a simple process of following a set of rules for mapping the various object model types into XML elements. At the top-level of the iCalendar object model is an "iCalendar stream". This object encompasses multiple "iCalendar objects". In XML, the entire stream is contained in the root ICAL:icalendar XML element. Example: Daboo, et al. Expires December 6, 2009 [Page 4] Internet-Draft iCalendar in XML June 2009 ... An iCalendar stream can contain one or more iCalendar objects. Each iCalendar object, delimited by BEGIN:VCALENDAR and END:VCALENDAR, is enclosed by the ICAL:vcalendar XML element. Example: ... iCalendar objects are comprised of a set of "components", "properties", "parameters" and "values". A "component" can contain other "components" or "properties". A "property" has a value and optionally a set of "parameters". In XML, "components" are contained within an ICAL:components XML element. With that element, another ICAL:components element could appear (representing components nested within components) or the ICAL:properties XML element could appear. ICAL:properties is used to encapsulate iCalendar properties. Each iCalendar property will be mapped to its own XML element as described below. Within each of these elements there is an optional ICAL:parameters XML element used to encapsulate any iCalendar parameters. Additionally there will be one or more XML elements representing the value of the iCalendar property. Example: ... ... Daboo, et al. Expires December 6, 2009 [Page 5] Internet-Draft iCalendar in XML June 2009 +------------------+----------------+------------------+ | Item | XML element | XML Definition | +------------------+----------------+------------------+ | iCalendar Stream | ICAL:icalendar | Appendix A # 3.4 | | VCALENDAR | ICAL:vcalendar | Appendix A # 3.6 | +------------------+----------------+------------------+ 3.3. Components (2445bis section 3.6) Each calendar component in the VCALENDAR object, delimited by BEGIN and END, will be converted to an enclosing XML element with the same name, but in lowercase: +-----------+----------------+--------------------+ | Component | XML element | XML Definition | +-----------+----------------+--------------------+ | VEVENT | ICAL:vevent | Appendix A # 3.6.1 | | VTODO | ICAL:vtodo | Appendix A # 3.6.2 | | VJOURNAL | ICAL:vjournal | Appendix A # 3.6.3 | | VFREEBUSY | ICAL:vfreebusy | Appendix A # 3.6.4 | | VTIMEZONE | ICAL:vtimezone | Appendix A # 3.6.5 | | STANDARD | ICAL:standard | Appendix A # 3.6.5 | | DAYLIGHT | ICAL:daylight | Appendix A # 3.6.5 | | VALARM | ICAL:valarm | Appendix A # 3.6.6 | +-----------+----------------+--------------------+ 3.4. Properties (2445bis section 3.5) iCalendar properties , whether they apply to the VCALENDAR object or to the components, are handled in a consistent way. iCalendar properties are enclosed in the XML element ICAL:properties. Each invidivual iCalendar property is represented in XML by an element of the same name as the iCalendar property, but in lowercase. For example, the CALSCALE property is represented in XML by the ICAL: calscale element. Example: Daboo, et al. Expires December 6, 2009 [Page 6] Internet-Draft iCalendar in XML June 2009 ... ... ... ... Each property can contain an ICAL:parameters XML element encapsulating any iCalendar parameters associated with the iCalendar property. Each property will contain one or more "value" XML elements as described below representing the value of the iCalendar property. +------------------+-----------------------+-----------------------+ | Property | XML element | XML Definition | +------------------+-----------------------+-----------------------+ | CALSCALE | ICAL:calscale | Appendix A # 3.7.1 | | METHOD | ICAL:method | Appendix A # 3.7.2 | | PRODID | ICAL:prodid | Appendix A # 3.7.3 | | VERSION | ICAL:version | Appendix A # 3.7.4 | | ATTACH | ICAL:attach | Appendix A # 3.8.1.1 | | CATEGORIES | ICAL:categories | Appendix A # 3.8.1.2 | | CLASS | ICAL:class | Appendix A # 3.8.1.3 | | COMMENT | ICAL:comment | Appendix A # 3.8.1.4 | | DESCRIPTION | ICAL:description | Appendix A # 3.8.1.5 | | GEO | ICAL:geo | Appendix A # 3.8.1.6 | | LOCATION | ICAL:location | Appendix A # 3.8.1.7 | | PERCENT-COMPLETE | ICAL:percent-complete | Appendix A # 3.8.1.8 | | PRIORITY | ICAL:priority | Appendix A # 3.8.1.9 | | RESOURCES | ICAL:resources | Appendix A # 3.8.1.10 | | STATUS | ICAL:status | Appendix A # 3.8.1.11 | | SUMMARY | ICAL:summary | Appendix A # 3.8.1.12 | | COMPLETED | ICAL:completed | Appendix A # 3.8.2.1 | | DTEND | ICAL:dtend | Appendix A # 3.8.2.2 | | DUE | ICAL:due | Appendix A # 3.8.2.3 | | DTSTART | ICAL:dtstart | Appendix A # 3.8.2.4 | | DURATION | ICAL:duration | Appendix A # 3.8.2.5 | | FREEBUSY | ICAL:freebusy | Appendix A # 3.8.2.6 | | TRANSP | ICAL:transp | Appendix A # 3.8.2.7 | | TZID | ICAL:tzid | Appendix A # 3.8.3.1 | Daboo, et al. Expires December 6, 2009 [Page 7] Internet-Draft iCalendar in XML June 2009 | TZNAME | ICAL:tzname | Appendix A # 3.8.3.2 | | TZOFFSETFROM | ICAL:tzoffsetfrom | Appendix A # 3.8.3.3 | | TZOFFSETTO | ICAL:tzoffsetto | Appendix A # 3.8.3.4 | | TZURL | ICAL:tzurl | Appendix A # 3.8.3.5 | | ATTENDEE | ICAL:attendee | Appendix A # 3.8.4.1 | | CONTACT | ICAL:contact | Appendix A # 3.8.4.2 | | ORGANIZER | ICAL:organizer | Appendix A # 3.8.4.3 | | RECURRENCE-ID | ICAL:recurrence-id | Appendix A # 3.8.4.4 | | RELATED-TO | ICAL:related-to | Appendix A # 3.8.4.5 | | URL | ICAL:url | Appendix A # 3.8.4.6 | | UID | ICAL:uid | Appendix A # 3.8.4.7 | | EXDATE | ICAL:exdate | Appendix A # 3.8.5.1 | | RDATE | ICAL:rdate | Appendix A # 3.8.5.2 | | RRULE | ICAL:rrule | Appendix A # 3.8.5.3 | | ACTION | ICAL:action | Appendix A # 3.8.6.1 | | REPEAT | ICAL:repeat | Appendix A # 3.8.6.2 | | TRIGGER | ICAL:trigger | Appendix A # 3.8.6.3 | | CREATED | ICAL:created | Appendix A # 3.8.7.1 | | DTSTAMP | ICAL:dtstamp | Appendix A # 3.8.7.2 | | LAST-MODIFIED | ICAL:last-modified | Appendix A # 3.8.7.3 | | SEQUENCE | ICAL:sequence | Appendix A # 3.8.7.4 | | REQUEST-STATUS | ICAL:request-status | Appendix A # 3.8.8.3 | +------------------+-----------------------+-----------------------+ 3.4.1. Special Cases for Properties Some properties in iCalendar can contain "structured" value data. This includes lists of "standard" value types, as well as values with specific "fields". In XML, these "structured" values are represented as separate XML elements in various ways for ease of processing using standard XML tools. 3.4.1.1. Multi-valued Properties The following iCalendar properties can have values that consist of a list of "standard" iCalendar values separated by a specific delimiter. In XML these properties are represented by an XML element that contains multiple "value" elements (Section 3.6). +------------+-----------------+-----------------------+ | Property | XML element | XML Definition | +------------+-----------------+-----------------------+ | CATEGORIES | ICAL:categories | Appendix A # 3.8.1.2 | | RESOURCES | ICAL:resources | Appendix A # 3.8.1.10 | | FREEBUSY | ICAL:freebusy | Appendix A # 3.8.2.6 | | EXDATE | ICAL:exdate | Appendix A # 3.8.5.1 | | RDATE | ICAL:rdate | Appendix A # 3.8.5.2 | +------------+-----------------+-----------------------+ Daboo, et al. Expires December 6, 2009 [Page 8] Internet-Draft iCalendar in XML June 2009 3.4.1.2. GEO Property In iCalendar, the GEO property value is defined as a semi-colon separated list of two FLOAT values, the first representing latitude and the second longitude. In XML, the value for the ICAL:geo element is represented by an ICAL: value element containing an ICAL:latitude element and an ICAL: longitude element, each of which contain text values representing the FLOAT values. See Appendix A # 3.8.1.6. 3.4.1.3. REQUEST-STATUS Property In Icalendar, the REQUEST-STATUS property value is defined as a semi- colon separated list of two or three TEXT values. The first represents a code, the second a description, and the third (optional) additional data. In XML, the value for the ICAL:request-status element is represented by an ICAL:value element containing an ICAL:code element, and iCAL: description element, and optionally and ICAL:data element, each of which contain the corresponding TEXT values. See Appendix A # 3.8.8.3. 3.5. Parameters (2445bis section 3.4) iCalendar parameters are enclosed in the XML element ICAL:parameters which optionally occurs once in each property XML element. Each invidivual iCalendar parameter is represented in XML by an element of the same name as the iCalendar parameter, but in lowercase. For example, the PARTSTAT parameter is represented in XML by the ICAL:partstat element. Example: Daboo, et al. Expires December 6, 2009 [Page 9] Internet-Draft iCalendar in XML June 2009 ... ... NEEDS-ACTION ... Each parameter contains either text, or one or more child XML elements representing iCalendar value types. +----------------+---------------------+---------------------+ | Parameter | XML element | XML Definition | +----------------+---------------------+---------------------+ | ALTREP | ICAL:altrep | Appendix A # 3.2.1 | | CN | ICAL:cn | Appendix A # 3.2.2 | | CUTYPE | ICAL:cutype | Appendix A # 3.2.3 | | DELEGATED-FROM | ICAL:delegated-from | Appendix A # 3.2.4 | | DELEGATED-TO | ICAL:delegated-to | Appendix A # 3.2.5 | | DIR | ICAL:dir | Appendix A # 3.2.6 | | ENCODING | ICAL:encoding | Appendix A # 3.2.7 | | FMTTYPE | ICAL:fmttype | Appendix A # 3.2.8 | | FBTYPE | ICAL:fbtype | Appendix A # 3.2.9 | | LANGUAGE | ICAL:language | Appendix A # 3.2.10 | | MEMBER | ICAL:member | Appendix A # 3.2.11 | | PARTSTAT | ICAL:partstat | Appendix A # 3.2.12 | | RANGE | ICAL:range | Appendix A # 3.2.13 | | RELATED | ICAL:related | Appendix A # 3.2.14 | | RELTYPE | ICAL:reltype | Appendix A # 3.2.15 | | ROLE | ICAL:role | Appendix A # 3.2.16 | | RSVP | ICAL:rsvp | Appendix A # 3.2.17 | | SENT-BY | ICAL:sent-by | Appendix A # 3.2.18 | | TZID | ICAL:tzid | Appendix A # 3.2.19 | +----------------+---------------------+---------------------+ 3.5.1. VALUE parameter iCalendar defines a VALUE parameter (Section 3.2.20 of [I-D.ietf-calsify-rfc2445bis]. This parameter is not mapped to an XML element. Instead, the value type is handled by having different XML elements for each value, and these appear inside of ICAL:property Daboo, et al. Expires December 6, 2009 [Page 10] Internet-Draft iCalendar in XML June 2009 elements. Thus, when converting from iCalendar to XML, any VALUE parameters are skipped. When converting from XML into iCalendar, the appropriate VALUE parameter MUST be included in the iCalendar property if the value type is not the default value type for that property. 3.6. Values (2445bis section 3.3) iCalendar value types are mapped into XML elements with a matching name in all lowercase. In some cases, iCalendar defines "structured" values and these are mapped into separate child elements in each value element, as described by the simple DTD definitions below. Some properties allow for multiple values and these are represented by separate matching value XML elements. 3.6.1. Binary (2445bis section 4.3.1) Description: iCalendar BINARY property values are represented by the ICAL:binary XML element. The content of the element is base64 encoded data. Whitespace MAY be inserted into the data at any point to "wrap" the data to reasonable line lengths. When converting back to iCalendar the whitespace MUST first be removed. XML Definition: Appendix A # 3.3.1 3.6.2. Boolean (2445bis section 4.3.2) Description: iCalendar BOOLEAN property values are represented by the ICAL:boolean XML element. The content of the element is text containing either of "TRUE" or "FALSE". XML Definition: Appendix A # 3.3.2 3.6.3. Calendar User Address (2445bis section 4.3.3) Description: iCalendar CAL-ADDRESS property values are represented by the ICAL:cal-address XML element. The content of the element is a URI. XML Definition: Appendix A # 3.3.3 3.6.4. Date (2445bis section 4.3.4) Daboo, et al. Expires December 6, 2009 [Page 11] Internet-Draft iCalendar in XML June 2009 Description: iCalendar DATE property values are represented by the ICAL:date XML element. The content of the element is three child elements representing the year, month and day values in the date. XML Definition: Appendix A # 3.3.4 3.6.5. Date-Time (2445bis section 4.3.5) Description: iCalendar DATE-TIME property values are represented by the ICAL:date-time XML element. The content of the element is six child elements representing the year, month, day, hour, minute and second values in the date-time. In addition, an XML attribute is used to indicate whether the date-time value represents a UTC based date-time (represented by a trailing "Z" in the iCalendar value). XML Definition: Appendix A # 3.3.5 3.6.6. Duration (2445bis section 4.3.6) Description: iCalendar DURATION property values are represented by the ICAL:duration XML element. The content of the element is various child elements representing the possible combinations of week, day, hour, minute and second values. In addition, an XML attribute is used to indicate whether the duration value represents a positive or negative offset. XML Definition: Appendix A # 3.3.6 3.6.7. Float (2445bis section 4.3.7) Description: iCalendar FLOAT property values are represented by the ICAL:float XML element. The content of the element is a text representation of a floating point number. XML Definition: Appendix A # 3.3.7 3.6.8. Integer (2445bis section 4.3.8) Description: iCalendar INTEGER property values are represented by the ICAL:integer XML element. The content of the element is a text representation of an integer number. XML Definition: Appendix A # 3.3.8 Daboo, et al. Expires December 6, 2009 [Page 12] Internet-Draft iCalendar in XML June 2009 3.6.9. Period of Time (2445bis section 4.3.9) Description: iCalendar PERIOD property values are represented by the ICAL:period XML element. The content of the element is two child elements representing the start date-time and end date-time or positive duration. XML Definition: Appendix A # 3.3.9 3.6.10. Recurrence Rule (2445bis section 4.3.10) Description: iCalendar RECUR property values are represented by the ICAL:recur XML element. The content of the element is child elements representing the various components of a recurrence rule. XML Definition: Appendix A # 3.3.10 3.6.11. Text (2445bis section 4.3.11) Description: iCalendar TEXT property values are represented by the ICAL:text XML element. The content of the element is simple text. XML Definition: Appendix A # 3.3.11 3.6.12. Time (2445bis section 4.3.12) Description: iCalendar TIME property values are represented by the ICAL:time XML element. The content of the element is three child elements representing the hour, minute and second values in the time. In addition, an XML attribute is used to indicate whether the time value represents a UTC based time (represented by a trailing "Z" in the iCalendar value). XML Definition: Appendix A # 3.3.12 3.6.13. URI (2445bis section 4.3.13) Description: iCalendar URI property values are represented by the ICAL:uri XML element. The content of the element is a URI. XML Definition: Appendix A # 3.3.13 3.6.14. UTC Offset (2445bis section 4.3.14) Daboo, et al. Expires December 6, 2009 [Page 13] Internet-Draft iCalendar in XML June 2009 Description: iCalendar UTC-OFFSET property values are represented by the ICAL:utc-offset XML element. The content of the element is two or three child elements representing the hour, minute and (optional) second values in the UTC offset. In addition, an XML attribute is used to indicate whether the offset value represents a positive or negative offset. XML Definition: Appendix A # 3.3.14 3.7. Extensions iCalendar extension properties and parameters (ones with an "X-" prefix in their name) are handled in the same way as other properties and parameters: the property or parameter is represented by an XML element with the same name, but in lowercase. e.g., the "X-FOO" property in iCalendar turns into the ICAL:x-foo element in XML. 4. Converting from XML into iCalendar When converting from XML back to iCalendar, any elements in the XML that are not in the "urn:ietf:params:xml:ns:icalendar" namespace MUST be ignored. When converting component, property and parameter values, the names SHOULD be converted to uppercase. Although iCalendar names are case insensitive, common practice is to keep them all uppercase following the actual definitions in [I-D.ietf-calsify-rfc2445bis]. Backslash escaping and line folding MUST be applied to the resulting iCalendar data as required by [I-D.ietf-calsify-rfc2445bis]. 5. Security Considerations This extension does not introduce any new security concerns than those already described in iCalendar. 6. IANA Considerations This document uses one new URN to identify a new XML namespace, and one new media type. The URN conforms to a registry mechanism described in [RFC3688]. 6.1. Namespace Registration Registration request for the iCalendar namespace: URI: urn:ietf:params:xml:ns:icalendar Daboo, et al. Expires December 6, 2009 [Page 14] Internet-Draft iCalendar in XML June 2009 Registrant Contact: See the "Authors' Addresses" section of this document. XML: None. Namespace URIs do not represent an XML specification. 6.2. Media Type This section defines the MIME media type for use with iCalendar in XML data. To: ietf-types@iana.org Subject: Registration of media type application/xml+calendar Type name: application Subtype name: xml+calendar Required parameters: none Optional parameters: charset, method, component and optinfo as defined for the text/calendar media type Encoding considerations: iCalendar data is typically UTF-8 and thus the XML representation will follow that. As a result, for 7-bit transports, data in UTF-8 MUST be encoded in quoted-printable or base64. Security considerations: See Section 5. Interoperability considerations: This media type provides an alternative syntax to iCalendar data based on XML. Published specification: This specification. Applications which use this media type: Applications that currently make use of the text/calendar media type can use this as an alternative. Additional information: Magic number(s): None File extension(s): XML data should use "xml" as the file extension. Daboo, et al. Expires December 6, 2009 [Page 15] Internet-Draft iCalendar in XML June 2009 Macintosh file type code(s): None specified. Person & email address to contact for further information: See the "Author's Address" section of this document. Intended usage: COMMON Restrictions on usage: There are no restrictions on where this media type can be used. Author: See the "Author's Address" section of this document. Change controller: IETF 7. Acknowledgments This specification originated from the work of the XML technical committee of the Calendaring and Scheduling Consortium. 8. Normative References [I-D.ietf-calsify-rfc2445bis] Desruisseaux, B., "Internet Calendaring and Scheduling Core Object Specification (iCalendar)", draft-ietf-calsify-rfc2445bis-10 (work in progress), April 2009. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. Appendix A. Relax NG Schema Below is a Relax NG schema for iCalendar in XML. This schema uses the compact notation of Relax NG. The numeric section numbers given in the comments refer to section in [I-D.ietf-calsify-rfc2445bis]. The ordering of elements follows the section ordering of [I-D.ietf-calsify-rfc2445bis]. The Relax NG compact notation "?" operator is used to indicate an unordered list of items. However, that operator, as defined, allows "mixing" each element that it operates on at any depth within the other elements, rather than just allowing "mixing" of siblings only. As a result, the schema provided allows certain constructs that are not allowed in iCalendar. Given that there is no sibling-only Daboo, et al. Expires December 6, 2009 [Page 16] Internet-Draft iCalendar in XML June 2009 unordered list operator in RelaxNG, this is the best representation that can be given. # Relax NG Schema for iCalendar in XML default namespace = "urn:ietf:params:xml:ns:icalendar" # 3.2 Property Parameters # 3.2.1 Alternate Text Representation altrepparam = element altrep { value-uri } # 3.2.2 Common Name cnparam = element cn { text } # 3.2.3 Calendar User Type cutypeparam = element cutype { "INDIVIDUAL" | "GROUP" | "RESOURCE" | "ROOM" | "UNKNOWN" } # 3.2.4 Delegators delfromparam = element delegated-from { value-cal-address+ } # 3.2.5 Delegatees deltoparam = element delegated-to { value-cal-address+ } # 3.2.6 Directory Entry Reference dirparam = element dir { value-uri } # 3.2.7 Inline Encoding encodingparam = element encoding { "8BIT" | "BASE64" } # 3.2.8 Format Type Daboo, et al. Expires December 6, 2009 [Page 17] Internet-Draft iCalendar in XML June 2009 fmttypeparam = element fmttype { text } # 3.2.9 Free/Busy Time Type fbtypeparam = element fbtype { "FREE" | "BUSY" | "BUSY-UNAVAILABLE" | "BUSY-TENTATIVE" } # 3.2.10 Language languageparam = element language { text } # 3.2.11 Group or List Membership memberparam = element member { value-cal-address+ } # 3.2.12 Participation Status partstatparam = element partstat { type-partstat-event | type-partstat-todo | type-partstat-jour } type-partstat-event = ( "NEEDS-ACTION" | "ACCEPTED" | "DECLINED" | "TENTATIVE" | "DELEGATED" ) type-partstat-todo = ( "NEEDS-ACTION" | "ACCEPTED" | "DECLINED" | "TENTATIVE" | "DELEGATED" | "COMPLETED" | "IN-PROCESS" ) type-partstat-jour = ( "NEEDS-ACTION" | "ACCEPTED" | Daboo, et al. Expires December 6, 2009 [Page 18] Internet-Draft iCalendar in XML June 2009 "DECLINED" ) # 3.2.13 Recurrence Identifier Range rangeparam = element range { "THISANDFUTURE" } # 3.2.14 Alarm Trigger Relationship trigrelparam = element related { "START" | "END" } # 3.2.15 Relationship Type reltypeparam = element reltype { "PARENT" | "CHILD" | "SIBLING" } # 3.2.16 Participation Role roleparam = element role { "CHAIR" | "REQ-PARTICIPANT" | "OPT-PARTICIPANT" | "NON-PARTICIPANT" } # 3.2.17 RSVP Expectation rsvpparam = element rsvp { "TRUE" | "FALSE" } # 3.2.18 Sent By sentbyparam = element sent-by { value-cal-address } # 3.2.19 Time Zone Identifier tzidparam = element tzid { text } Daboo, et al. Expires December 6, 2009 [Page 19] Internet-Draft iCalendar in XML June 2009 # 3.3 Property Value Data Types # 3.3.1 BINARY value-binary = element binary { text } # 3.3.2 BOOLEAN value-boolean = element boolean { ("TRUE" | "FALSE") } # 3.3.3 CAL-ADDRESS value-cal-address = element cal-address { text } # 3.3.4 DATE value-date = element date { element year { text }, element month { text }, element day { text } } # 3.3.5 DATE-TIME value-date-time = element date-time { attribute utc { "yes" | "no" }, element year { text }, element month { text }, element day { text }, element hour { text }, element minute { text }, element second { text } } # 3.3.6 DURATION value-duration = element duration { attribute sign { "+" | "-" }, ( ( element day { text }, element hour { text }?, element minute { text }?, element second { text }? ) | ( Daboo, et al. Expires December 6, 2009 [Page 20] Internet-Draft iCalendar in XML June 2009 element hour { text }, element minute { text }?, element second { text }? ) | ( element minute { text }, element second { text }? ) | ( element second { text } ) | element week { text } ) } # 3.3.7 FLOAT value-float = element float { text } # 3.3.8 INTEGER value-integer = element integer { text } # 3.3.9 PERIOD value-period = element period { value-date-time, ( value-date-time | value-duration ) } # 3.3.10 RECUR value-recur = element recur { type-freq, (type-until | type-count)?, element interval { text }?, element bysecond { text }*, element byminute { text }*, element byhour { text }*, type-byday*, type-bymonthday*, type-byyearday*, type-byweekno*, element bymonth { text }*, type-bysetpos*, Daboo, et al. Expires December 6, 2009 [Page 21] Internet-Draft iCalendar in XML June 2009 element wkst { type-weekday }? } type-freq = element freq { "SECONDLY" | "MINUTELY" | "HOURLY" | "DAILY" | "WEEKLY" | "MONTHLY" | "YEARLY" } type-until = element until { type-date | type-date-time } type-count = element count { text } type-weekday = ( "SU" | "MO" | "TU" | "WE" | "TH" | "FR" | "SA" ) type-byday = element byday { element ordwk { text }?, element weekday { type-weekday } } type-bymonthday = element bymonthday { text } type-byyearday = element byyearday { text } type-byweekno = element byweekno { text } Daboo, et al. Expires December 6, 2009 [Page 22] Internet-Draft iCalendar in XML June 2009 type-bysetpos = element bysetpos { text } # 3.3.11 TEXT value-text = element text { text } # 3.3.12 TIME value-time = element time { attribute utc { "yes" | "no" }, element hour { text }, element minute { text }, element second { text } } # 3.3.13 URI value-uri = element uri { text } # 3.3.14 UTC-OFFSET value-utc-offset = element utc-offset { attribute sign { "+" | "-" }, element hour { text }, element minute { text }, element second { text }? } # 3.4 iCalendar Stream start = element icalendar { vcalendar+ } # 3.6 Calendar Components vcalendar = element vcalendar { type-calprops, type-component } type-calprops = element properties { property-prodid & property-version & property-calscale? & property-method? } Daboo, et al. Expires December 6, 2009 [Page 23] Internet-Draft iCalendar in XML June 2009 type-component = element components { ( component-vevent | component-vtodo | component-vjournal | component-vfreebusy | component-vtimezone )* } # 3.6.1 Event Component component-vevent = element vevent { type-eventprop, element components { component-valarm+ }? } type-eventprop = element properties { property-dtstamp & property-dtstart & property-uid & property-class? & property-created? & property-description? & property-geo? & property-last-mod? & property-location? & property-organizer? & property-priority? & property-seq? & property-status-event? & property-summary? & property-transp? & property-url? & property-recurid? & property-rrule? & (property-dtend | property-duration)? & property-attach* & property-attendee* & property-categories* & property-comment* & property-contact* & Daboo, et al. Expires December 6, 2009 [Page 24] Internet-Draft iCalendar in XML June 2009 property-exdate* & property-rstatus* & property-related* & property-resources* & property-rdate* } # 3.6.2 To-do Component component-vtodo = element vtodo { type-todoprop, element components { component-valarm+ }? } type-todoprop = element properties { property-dtstamp & property-uid & property-class? & property-completed? & property-created? & property-description? & property-geo? & property-last-mod? & property-location? & property-organizer? & property-percent? & property-priority? & property-recurid? & property-seq? & property-status-todo? & property-summary? & property-url? & property-rrule? & ( (property-dtstart?, property-dtend? ) | (property-dtstart, property-duration)? ) & property-attach* & property-attendee* & property-categories* & property-comment* & property-contact* & Daboo, et al. Expires December 6, 2009 [Page 25] Internet-Draft iCalendar in XML June 2009 property-exdate* & property-rstatus* & property-related* & property-resources* & property-rdate* } # 3.6.3 Journal Component component-vjournal = element vjournal { type-jourprop } type-jourprop = element properties { property-dtstamp & property-uid & property-class? & property-created? & property-dtstart? & property-last-mod? & property-organizer? & property-recurid? & property-seq? & property-status-jour? & property-summary? & property-url? & property-rrule? & property-attach* & property-attendee* & property-categories* & property-comment* & property-contact* & property-description? & property-exdate* & property-related* & property-rdate* & property-rstatus* } # 3.6.4 Free/Busy Component component-vfreebusy = element vfreebusy { type-fbprop } Daboo, et al. Expires December 6, 2009 [Page 26] Internet-Draft iCalendar in XML June 2009 type-fbprop = element properties { property-dtstamp & property-uid & property-contact? & property-dtstart? & property-dtend? & property-duration? & property-organizer? & property-url? & property-attendee* & property-comment* & property-freebusy* & property-rstatus* } # 3.6.5 Time Zone Component component-vtimezone = element vtimezone { element properties { property-tzid & property-last-mod? & property-tzuurl? }, element components { (component-standard | component-daylight) & component-standard* & component-daylight* } } component-standard = element standard { type-tzprop } component-daylight = element daylight { type-tzprop } type-tzprop = element properties { property-dtstart & property-tzoffsetto & property-tzoffsetfrom & property-rrule? & Daboo, et al. Expires December 6, 2009 [Page 27] Internet-Draft iCalendar in XML June 2009 property-comment* & property-rdate* & property-tzname* } # 3.6.6 Alarm Component component-valarm = element valarm { audioprop | dispprop | emailprop } type-audioprop = element properties { property-action & property-trigger & (property-duration, property-repeat)? & property-attach? } type-dispprop = element properties { property-action & property-description & property-trigger & property-summary & property-attendee+ & (property-duration, property-repeat)? & property-attach* } type-emailprop = element properties { property-action & property-description & property-trigger & (property-duration, property-repeat)? } # 3.7 Calendar Properties # 3.7.1 Calendar Scale property-calscale = element calscale { element parameters { empty }?, Daboo, et al. Expires December 6, 2009 [Page 28] Internet-Draft iCalendar in XML June 2009 element text { "GREGORIAN" } } # 3.7.2 Method property-method = element method { element parameters { empty }?, value-text } # 3.7.3 Product Identifier property-prodid = element prodid { element parameters { empty }?, value-text } # 3.7.4 Version property-version = element version { element parameters { empty }?, value-text } # 3.8 Component Properties # 3.8.1 Descriptive Component Properties # 3.8.1.1 Attachment property-attach = element attach { element parameters { fmttypeparam? & encodingparam? }?, value-uri | value-binary } # 3.8.1.2 Categories Daboo, et al. Expires December 6, 2009 [Page 29] Internet-Draft iCalendar in XML June 2009 property-categories = element categories { element parameters { languageparam? & }?, value-text+ } # 3.8.1.3 Classification property-class = element class { element parameters { empty }?, element text { "PUBLIC" | "PRIVATE" | "CONFIDENTIAL" } } # 3.8.1.4 Comment property-comment = element comment { element parameters { altrepparam? & languageparam? }?, value-text } # 3.8.1.5 Description property-description = element description { element parameters { altrepparam? & languageparam? }?, value-text } # 3.8.1.6 Geographic Position Daboo, et al. Expires December 6, 2009 [Page 30] Internet-Draft iCalendar in XML June 2009 property-geo = element geo { element parameters { empty }?, element value { element latitude { text }, element longitude { text } } } # 3.8.1.7 Location property-location = element location { element parameters { altrepparam? & languageparam? }?, value-text } # 3.8.1.8 Percent Complete property-percent = element percent-complete { element parameters { empty }?, value-integer } # 3.8.1.9 Priority property-priority = element priority { element parameters { empty }?, value-integer } # 3.8.1.10 Resources property-resources = element resources { element parameters { altrepparam? & languageparam? }?, Daboo, et al. Expires December 6, 2009 [Page 31] Internet-Draft iCalendar in XML June 2009 value-text+ } # 3.8.1.11 Status property-status-event = element status { element parameters { empty }?, element text { "TENTATIVE" | "CONFIRMED" | "CANCELLED" } } property-status-todo = element status { element parameters { empty }?, element text { "NEEDS-ACTION" | "COMPLETED" | "IN-PROCESS" | "CANCELLED" } } property-status-jour = element status { element parameters { empty }?, element text { "DRAFT" | "FINAL" | "CANCELLED" } } # 3.8.1.12 Summary property-summary = element summary { element parameters { altrepparam? & languageparam? }?, Daboo, et al. Expires December 6, 2009 [Page 32] Internet-Draft iCalendar in XML June 2009 value-text } # 3.8.2 Date and Time Component Properties # 3.8.2.1 Date/Time Completed property-completed = element completed { element parameters { empty }?, value-date-time } # 3.8.2.2 Date/Time End property-dtend = element dtend { element parameters { tzidparam? }?, value-date-time | value-date } # 3.8.2.3 Date/Time Due property-due = element due { element parameters { tzidparam? }?, value-date-time | value-date } # 3.8.2.4 Date/Time Start property-dtstart = element dtstart { element parameters { tzidparam? }?, value-date-time | value-date Daboo, et al. Expires December 6, 2009 [Page 33] Internet-Draft iCalendar in XML June 2009 } # 3.8.2.5 Duration property-duration = element duration { element parameters { empty }?, value-duration } # 3.8.2.6 Free/Busy Time property-freebusy = element freebusy { element parameters { fbtypeparam? }?, value-period+ } # 3.8.2.7 Time Transparency property-transp = element transp { element parameters { empty }?, element text { "OPAQUE" | "TRANSPARENT" } } # 3.8.3 Time Zone Component Properties # 3.8.3.1 Time Zone Identifier property-tzid = element tzid { element parameters { empty }?, value-text } # 3.8.3.2 Time Zone Name Daboo, et al. Expires December 6, 2009 [Page 34] Internet-Draft iCalendar in XML June 2009 property-tzname = element tzname { element parameters { languageparam? }?, value-text } # 3.8.3.3 Time Zone Offset From property-tzoffsetfrom = element tzoffsetfrom { element parameters { empty }?, value-utc-offset } # 3.8.3.4 Time Zone Offset To property-tzoffsetto = element tzoffsetto { element parameters { empty }?, value-utc-offset } # 3.8.3.5 Time Zone URL property-tzurl = element tzurl { element parameters { empty }?, value-uri } # 3.8.4 Relationship Component Properties # 3.8.4.1 Attendee property-attendee = element attendee { element parameters { cutypeparam? & memberparam? & roleparam? & partstatparam? & rsvpparam? & Daboo, et al. Expires December 6, 2009 [Page 35] Internet-Draft iCalendar in XML June 2009 deltoparam? & delfromparam? & sentbyparam? & cnparam? & dirparam? & languageparam? }?, value-cal-address } # 3.8.4.2 Contact property-contact = element contact { element parameters { altrepparam? & languageparam? }?, value-text } # 3.8.4.3 Organizer property-organizer = element organizer { element parameters { cnparam? & dirparam? & sentbyparam? & languageparam? }?, value-cal-address } # 3.8.4.4 Recurrence ID property-recurid = element recurrence-id { element parameters { tzidparam? & rangeparam? }?, value-date-time | value-date Daboo, et al. Expires December 6, 2009 [Page 36] Internet-Draft iCalendar in XML June 2009 } # 3.8.4.5 Related-To property-related = element related-to { element parameters { reltypeparam? }?, value-text } # 3.8.4.6 Uniform Resource Locator property-url = element url { element parameters { empty }?, value-uri } # 3.8.4.7 Unique Identifier property-uid = element uid { element parameters { empty }?, value-text } # 3.8.5 Recurrence Component Properties # 3.8.5.1 Exception Date/Times property-exdate = element exdate { element parameters { tzidparam? }?, value-date-time+ | value-date+ } # 3.8.5.2 Recurrence Date/Times property-rdate = element rdate { Daboo, et al. Expires December 6, 2009 [Page 37] Internet-Draft iCalendar in XML June 2009 element parameters { tzidparam? }?, value-date-time+ | value-date+ | value-period+ } # 3.8.5.3 Recurrence Rule property-rrule = element rrule { element parameters { empty }?, value-recur } # 3.8.6 Alarm Component Properties # 3.8.6.1 Action property-action = element action { element parameters { empty }?, element text { "AUDIO" | "DISPLAY" | "EMAIL" } } # 3.8.6.2 Repeat Count property-repeat = element repeat { element parameters { empty }?, value-integer } # 3.8.6.3 Trigger property-repeat = element repeat { ( element parameters { Daboo, et al. Expires December 6, 2009 [Page 38] Internet-Draft iCalendar in XML June 2009 trigrelparam? }?, value-duration ) | ( element parameters { empty }?, value-date-time ) } # 3.8.7 Change Management Component Properties # 3.8.7.1 Date/Time Created property-created = element created { element parameters { empty }?, value-date-time } # 3.8.7.2 Date/Time Stamp property-dtstamp = element dtstamp { element parameters { empty }?, value-date-time } # 3.8.7.3 Last Modified property-last-mod = element last-modified { element parameters { empty }?, value-date-time } # 3.8.7.4 Sequence Number property-seq = element sequence { element parameters { empty }?, value-integer Daboo, et al. Expires December 6, 2009 [Page 39] Internet-Draft iCalendar in XML June 2009 } # 3.8.8 Miscellaneous Component Properties # 3.8.8.3 Request Status property-rstatus = element request-status { element parameters { languageparam? }?, element value { element code { text }, element description { text }, element data { text }? } } Appendix B. XML Stylesheet for conversion to iCalendar TO DO Appendix C. Example Below is some example iCalendar data and its representation in XML as defined by this specification. C.1. iCalendar Data BEGIN:VCALENDAR CALSCALE:GREGORIAN PRODID:-//Example Inc.//Example Calendar//EN VERSION:2.0 BEGIN:VEVENT DTSTAMP:20080205T191224Z DTSTART:20081006 SUMMARY:Planning meeting UID:4088E990AD89CB3DBB484909 END:VEVENT END:VCALENDAR Daboo, et al. Expires December 6, 2009 [Page 40] Internet-Draft iCalendar in XML June 2009 C.2. XML Data GREGORIAN -//Example Inc.//Example Calendar//EN 2.0 200825 191224 2008106 Planning meeting 4088E990AD89CB3DBB484909 Daboo, et al. Expires December 6, 2009 [Page 41] Internet-Draft iCalendar in XML June 2009 Authors' Addresses Cyrus Daboo Apple Inc. 1 Infinite Loop Cupertino, CA 95014 USA EMail: cyrus@daboo.name URI: http://www.apple.com/ Mike Douglass Rensselaer Polytechnic Institute 110 8th Street Troy, NY 12180 USA EMail: douglm@rpi.edu URI: http://www.rpi.edu/ Steven Lees Microsoft Corporation One Microsoft Way Redmond, WA 98052 USA EMail: Steven.Lees@microsoft.com URI: http://www.microsoft.com/ Daboo, et al. Expires December 6, 2009 [Page 42]