full implementation of RFC syntax - ics2txt - convert icalendar .ics file to plain text
(HTM) git clone git://bitreich.org/ics2txt git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/ics2txt
(DIR) Log
(DIR) Files
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(DIR) README
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(DIR) commit 78e0184b4deb29669bfde9a66fc945968845ced8
(DIR) parent 90e6c1b1e36c4165ea9a20fa1c9fae85bb5152ec
(HTM) Author: Josuah Demangeon <me@josuah.net>
Date: Thu, 25 Jun 2020 23:55:55 +0200
full implementation of RFC syntax
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+Network Working Group B. Desruisseaux, Ed.
+Request for Comments: 5545 Oracle
+Obsoletes: 2445 September 2009
+Category: Standards Track
+
+
+ Internet Calendaring and Scheduling Core Object Specification
+ (iCalendar)
+
+Abstract
+
+This document defines the iCalendar data format for representing and
+exchanging calendaring and scheduling information such as events,
+to-dos, journal entries, and free/busy information, independent of any
+particular calendar service or protocol.
+
+Status of This Memo
+
+ This document specifies an Internet standards track protocol for the
+ Internet community, and requests discussion and suggestions for
+ improvements. Please refer to the current edition of the "Internet
+ Official Protocol Standards" (STD 1) for the standardization state
+ and status of this protocol. Distribution of this memo is unlimited.
+
+Copyright and License 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
+ (http://trustee.ietf.org/license-info) in effect on the date of
+ publication of this document. Please review these documents
+ carefully, as they describe your rights and restrictions with respect
+ to this document. Code Components extracted from this document must
+ include Simplified BSD License text as described in Section 4.e of
+ the Trust Legal Provisions and are provided without warranty as
+ described in the BSD License.
+
+ This document may contain material from IETF Documents or IETF
+ Contributions published or made publicly available before November
+ 10, 2008. The person(s) controlling the copyright in some of this
+ material may not have granted the IETF Trust the right to allow
+ modifications of such material outside the IETF Standards Process.
+ Without obtaining an adequate license from the person(s) controlling
+ the copyright in such materials, this document may not be modified
+ outside the IETF Standards Process, and derivative works of it may
+ not be created outside the IETF Standards Process, except to format
+
+
+
+Desruisseaux Standards Track [Page 1]
+
+RFC 5545 iCalendar September 2009
+
+
+ it for publication as an RFC or to translate it into languages other
+ than English.
+
+Table of Contents
+
+ 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5
+ 2. Basic Grammar and Conventions . . . . . . . . . . . . . . . . 6
+ 2.1. Formatting Conventions . . . . . . . . . . . . . . . . . 6
+ 2.2. Related Memos . . . . . . . . . . . . . . . . . . . . . . 7
+ 3. iCalendar Object Specification . . . . . . . . . . . . . . . 8
+ 3.1. Content Lines . . . . . . . . . . . . . . . . . . . . . . 8
+ 3.1.1. List and Field Separators . . . . . . . . . . . . . . 11
+ 3.1.2. Multiple Values . . . . . . . . . . . . . . . . . . . 11
+ 3.1.3. Binary Content . . . . . . . . . . . . . . . . . . . 11
+ 3.1.4. Character Set . . . . . . . . . . . . . . . . . . . . 12
+ 3.2. Property Parameters . . . . . . . . . . . . . . . . . . . 12
+ 3.2.1. Alternate Text Representation . . . . . . . . . . . . 13
+ 3.2.2. Common Name . . . . . . . . . . . . . . . . . . . . . 15
+ 3.2.3. Calendar User Type . . . . . . . . . . . . . . . . . 15
+ 3.2.4. Delegators . . . . . . . . . . . . . . . . . . . . . 16
+ 3.2.5. Delegatees . . . . . . . . . . . . . . . . . . . . . 16
+ 3.2.6. Directory Entry Reference . . . . . . . . . . . . . . 17
+ 3.2.7. Inline Encoding . . . . . . . . . . . . . . . . . . . 17
+ 3.2.8. Format Type . . . . . . . . . . . . . . . . . . . . . 18
+ 3.2.9. Free/Busy Time Type . . . . . . . . . . . . . . . . . 19
+ 3.2.10. Language . . . . . . . . . . . . . . . . . . . . . . 20
+ 3.2.11. Group or List Membership . . . . . . . . . . . . . . 20
+ 3.2.12. Participation Status . . . . . . . . . . . . . . . . 21
+ 3.2.13. Recurrence Identifier Range . . . . . . . . . . . . . 22
+ 3.2.14. Alarm Trigger Relationship . . . . . . . . . . . . . 23
+ 3.2.15. Relationship Type . . . . . . . . . . . . . . . . . . 24
+ 3.2.16. Participation Role . . . . . . . . . . . . . . . . . 25
+ 3.2.17. RSVP Expectation . . . . . . . . . . . . . . . . . . 25
+ 3.2.18. Sent By . . . . . . . . . . . . . . . . . . . . . . . 26
+ 3.2.19. Time Zone Identifier . . . . . . . . . . . . . . . . 26
+ 3.2.20. Value Data Types . . . . . . . . . . . . . . . . . . 28
+ 3.3. Property Value Data Types . . . . . . . . . . . . . . . . 29
+ 3.3.1. Binary . . . . . . . . . . . . . . . . . . . . . . . 29
+ 3.3.2. Boolean . . . . . . . . . . . . . . . . . . . . . . . 30
+ 3.3.3. Calendar User Address . . . . . . . . . . . . . . . . 30
+ 3.3.4. Date . . . . . . . . . . . . . . . . . . . . . . . . 31
+ 3.3.5. Date-Time . . . . . . . . . . . . . . . . . . . . . . 31
+ 3.3.6. Duration . . . . . . . . . . . . . . . . . . . . . . 34
+ 3.3.7. Float . . . . . . . . . . . . . . . . . . . . . . . . 35
+ 3.3.8. Integer . . . . . . . . . . . . . . . . . . . . . . . 35
+ 3.3.9. Period of Time . . . . . . . . . . . . . . . . . . . 36
+ 3.3.10. Recurrence Rule . . . . . . . . . . . . . . . . . . . 37
+ 3.3.11. Text . . . . . . . . . . . . . . . . . . . . . . . . 45
+
+
+
+Desruisseaux Standards Track [Page 2]
+
+RFC 5545 iCalendar September 2009
+
+
+ 3.3.12. Time . . . . . . . . . . . . . . . . . . . . . . . . 46
+ 3.3.13. URI . . . . . . . . . . . . . . . . . . . . . . . . . 48
+ 3.3.14. UTC Offset . . . . . . . . . . . . . . . . . . . . . 49
+ 3.4. iCalendar Object . . . . . . . . . . . . . . . . . . . . 49
+ 3.5. Property . . . . . . . . . . . . . . . . . . . . . . . . 50
+ 3.6. Calendar Components . . . . . . . . . . . . . . . . . . . 50
+ 3.6.1. Event Component . . . . . . . . . . . . . . . . . . . 52
+ 3.6.2. To-Do Component . . . . . . . . . . . . . . . . . . . 56
+ 3.6.3. Journal Component . . . . . . . . . . . . . . . . . . 58
+ 3.6.4. Free/Busy Component . . . . . . . . . . . . . . . . . 60
+ 3.6.5. Time Zone Component . . . . . . . . . . . . . . . . . 63
+ 3.6.6. Alarm Component . . . . . . . . . . . . . . . . . . . 72
+ 3.7. Calendar Properties . . . . . . . . . . . . . . . . . . . 77
+ 3.7.1. Calendar Scale . . . . . . . . . . . . . . . . . . . 77
+ 3.7.2. Method . . . . . . . . . . . . . . . . . . . . . . . 78
+ 3.7.3. Product Identifier . . . . . . . . . . . . . . . . . 79
+ 3.7.4. Version . . . . . . . . . . . . . . . . . . . . . . . 80
+ 3.8. Component Properties . . . . . . . . . . . . . . . . . . 81
+ 3.8.1. Descriptive Component Properties . . . . . . . . . . 81
+ 3.8.1.1. Attachment . . . . . . . . . . . . . . . . . . . 81
+ 3.8.1.2. Categories . . . . . . . . . . . . . . . . . . . 82
+ 3.8.1.3. Classification . . . . . . . . . . . . . . . . . 83
+ 3.8.1.4. Comment . . . . . . . . . . . . . . . . . . . . . 84
+ 3.8.1.5. Description . . . . . . . . . . . . . . . . . . . 85
+ 3.8.1.6. Geographic Position . . . . . . . . . . . . . . . 87
+ 3.8.1.7. Location . . . . . . . . . . . . . . . . . . . . 88
+ 3.8.1.8. Percent Complete . . . . . . . . . . . . . . . . 89
+ 3.8.1.9. Priority . . . . . . . . . . . . . . . . . . . . 90
+ 3.8.1.10. Resources . . . . . . . . . . . . . . . . . . . . 92
+ 3.8.1.11. Status . . . . . . . . . . . . . . . . . . . . . 93
+ 3.8.1.12. Summary . . . . . . . . . . . . . . . . . . . . . 94
+ 3.8.2. Date and Time Component Properties . . . . . . . . . 95
+ 3.8.2.1. Date-Time Completed . . . . . . . . . . . . . . . 95
+ 3.8.2.2. Date-Time End . . . . . . . . . . . . . . . . . . 96
+ 3.8.2.3. Date-Time Due . . . . . . . . . . . . . . . . . . 97
+ 3.8.2.4. Date-Time Start . . . . . . . . . . . . . . . . . 99
+ 3.8.2.5. Duration . . . . . . . . . . . . . . . . . . . . 100
+ 3.8.2.6. Free/Busy Time . . . . . . . . . . . . . . . . . 101
+ 3.8.2.7. Time Transparency . . . . . . . . . . . . . . . . 102
+ 3.8.3. Time Zone Component Properties . . . . . . . . . . . 103
+ 3.8.3.1. Time Zone Identifier . . . . . . . . . . . . . . 103
+ 3.8.3.2. Time Zone Name . . . . . . . . . . . . . . . . . 105
+ 3.8.3.3. Time Zone Offset From . . . . . . . . . . . . . . 106
+ 3.8.3.4. Time Zone Offset To . . . . . . . . . . . . . . . 106
+ 3.8.3.5. Time Zone URL . . . . . . . . . . . . . . . . . . 107
+ 3.8.4. Relationship Component Properties . . . . . . . . . . 108
+ 3.8.4.1. Attendee . . . . . . . . . . . . . . . . . . . . 108
+ 3.8.4.2. Contact . . . . . . . . . . . . . . . . . . . . . 111
+
+
+
+Desruisseaux Standards Track [Page 3]
+
+RFC 5545 iCalendar September 2009
+
+
+ 3.8.4.3. Organizer . . . . . . . . . . . . . . . . . . . . 113
+ 3.8.4.4. Recurrence ID . . . . . . . . . . . . . . . . . . 114
+ 3.8.4.5. Related To . . . . . . . . . . . . . . . . . . . 117
+ 3.8.4.6. Uniform Resource Locator . . . . . . . . . . . . 118
+ 3.8.4.7. Unique Identifier . . . . . . . . . . . . . . . . 119
+ 3.8.5. Recurrence Component Properties . . . . . . . . . . . 120
+ 3.8.5.1. Exception Date-Times . . . . . . . . . . . . . . 120
+ 3.8.5.2. Recurrence Date-Times . . . . . . . . . . . . . . 122
+ 3.8.5.3. Recurrence Rule . . . . . . . . . . . . . . . . . 124
+ 3.8.6. Alarm Component Properties . . . . . . . . . . . . . 134
+ 3.8.6.1. Action . . . . . . . . . . . . . . . . . . . . . 134
+ 3.8.6.2. Repeat Count . . . . . . . . . . . . . . . . . . 135
+ 3.8.6.3. Trigger . . . . . . . . . . . . . . . . . . . . . 135
+ 3.8.7. Change Management Component Properties . . . . . . . 138
+ 3.8.7.1. Date-Time Created . . . . . . . . . . . . . . . . 138
+ 3.8.7.2. Date-Time Stamp . . . . . . . . . . . . . . . . . 139
+ 3.8.7.3. Last Modified . . . . . . . . . . . . . . . . . . 140
+ 3.8.7.4. Sequence Number . . . . . . . . . . . . . . . . . 141
+ 3.8.8. Miscellaneous Component Properties . . . . . . . . . 142
+ 3.8.8.1. IANA Properties . . . . . . . . . . . . . . . . . 142
+ 3.8.8.2. Non-Standard Properties . . . . . . . . . . . . . 142
+ 3.8.8.3. Request Status . . . . . . . . . . . . . . . . . 144
+ 4. iCalendar Object Examples . . . . . . . . . . . . . . . . . . 146
+ 5. Recommended Practices . . . . . . . . . . . . . . . . . . . . 150
+ 6. Internationalization Considerations . . . . . . . . . . . . . 151
+ 7. Security Considerations . . . . . . . . . . . . . . . . . . . 151
+ 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 151
+ 8.1. iCalendar Media Type Registration . . . . . . . . . . . . 151
+ 8.2. New iCalendar Elements Registration . . . . . . . . . . . 155
+ 8.2.1. iCalendar Elements Registration Procedure . . . . . . 155
+ 8.2.2. Registration Template for Components . . . . . . . . 155
+ 8.2.3. Registration Template for Properties . . . . . . . . 156
+ 8.2.4. Registration Template for Parameters . . . . . . . . 156
+ 8.2.5. Registration Template for Value Data Types . . . . . 157
+ 8.2.6. Registration Template for Values . . . . . . . . . . 157
+ 8.3. Initial iCalendar Elements Registries . . . . . . . . . . 158
+ 8.3.1. Components Registry . . . . . . . . . . . . . . . . . 158
+ 8.3.2. Properties Registry . . . . . . . . . . . . . . . . . 158
+ 8.3.3. Parameters Registry . . . . . . . . . . . . . . . . . 161
+ 8.3.4. Value Data Types Registry . . . . . . . . . . . . . . 162
+ 8.3.5. Calendar User Types Registry . . . . . . . . . . . . 162
+ 8.3.6. Free/Busy Time Types Registry . . . . . . . . . . . . 163
+ 8.3.7. Participation Statuses Registry . . . . . . . . . . . 163
+ 8.3.8. Relationship Types Registry . . . . . . . . . . . . . 164
+ 8.3.9. Participation Roles Registry . . . . . . . . . . . . 164
+ 8.3.10. Actions Registry . . . . . . . . . . . . . . . . . . 165
+ 8.3.11. Classifications Registry . . . . . . . . . . . . . . 165
+ 8.3.12. Methods Registry . . . . . . . . . . . . . . . . . . 165
+
+
+
+Desruisseaux Standards Track [Page 4]
+
+RFC 5545 iCalendar September 2009
+
+
+ 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 165
+ 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 166
+ 10.1. Normative References . . . . . . . . . . . . . . . . . . 166
+ 10.2. Informative References . . . . . . . . . . . . . . . . . 167
+ Appendix A. Differences from RFC 2445 . . . . . . . . . . . . . 169
+ A.1. New Restrictions . . . . . . . . . . . . . . . . . . . . 169
+ A.2. Restrictions Removed . . . . . . . . . . . . . . . . . . 169
+ A.3. Deprecated Features . . . . . . . . . . . . . . . . . . . 169
+
+1. Introduction
+
+ The use of calendaring and scheduling has grown considerably in the
+ last decade. Enterprise and inter-enterprise business has become
+ dependent on rapid scheduling of events and actions using this
+ information technology. This memo is intended to progress the level
+ of interoperability possible between dissimilar calendaring and
+ scheduling applications. This memo defines a MIME content type for
+ exchanging electronic calendaring and scheduling information. The
+ Internet Calendaring and Scheduling Core Object Specification, or
+ iCalendar, allows for the capture and exchange of information
+ normally stored within a calendaring and scheduling application; such
+ as a Personal Information Manager (PIM) or a Group-Scheduling
+ product.
+
+ The iCalendar format is suitable as an exchange format between
+ applications or systems. The format is defined in terms of a MIME
+ content type. This will enable the object to be exchanged using
+ several transports, including but not limited to SMTP, HTTP, a file
+ system, desktop interactive protocols such as the use of a memory-
+ based clipboard or drag/drop interactions, point-to-point
+ asynchronous communication, wired-network transport, or some form of
+ unwired transport such as infrared.
+
+ The memo also provides for the definition of iCalendar object methods
+ that will map this content type to a set of messages for supporting
+ calendaring and scheduling operations such as requesting, replying
+ to, modifying, and canceling meetings or appointments, to-dos, and
+ journal entries. The iCalendar object methods can be used to define
+ other calendaring and scheduling operations such as requesting for
+ and replying with free/busy time data. Such a scheduling protocol is
+ defined in the iCalendar Transport-independent Interoperability
+ Protocol (iTIP) defined in [2446bis].
+
+ The memo also includes a formal grammar for the content type based on
+ the Internet ABNF defined in [RFC5234]. This ABNF is required for
+ the implementation of parsers and to serve as the definitive
+ reference when ambiguities or questions arise in interpreting the
+ descriptive prose definition of the memo. Additional restrictions
+
+
+
+Desruisseaux Standards Track [Page 5]
+
+RFC 5545 iCalendar September 2009
+
+
+ that could not easily be expressed with the ABNF syntax are specified
+ as comments in the ABNF. Comments with normative statements should
+ be treated as such.
+
+2. Basic Grammar and 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 memo makes use of both a descriptive prose and a more formal
+ notation for defining the calendaring and scheduling format.
+
+ The notation used in this memo is the ABNF notation of [RFC5234].
+ Readers intending on implementing the format defined in this memo
+ should be familiar with this notation in order to properly interpret
+ the specifications of this memo.
+
+ All numeric values used in this memo are given in decimal notation.
+
+ All names of properties, property parameters, enumerated property
+ values, and property parameter values are case-insensitive. However,
+ all other property values are case-sensitive, unless otherwise
+ stated.
+
+ Note: All indented editorial notes, such as this one, are intended
+ to provide the reader with additional information. The
+ information is not essential to the building of an implementation
+ conformant with this memo. The information is provided to
+ highlight a particular feature or characteristic of the memo.
+
+ The format for the iCalendar object is based on the syntax of the
+ text/directory media type [RFC2425]. While the iCalendar object is
+ not a profile of the text/directory media type [RFC2425], it does
+ reuse a number of the elements from the [RFC2425] specification.
+
+2.1. Formatting Conventions
+
+ The elements defined in this memo are defined in prose. Many of the
+ terms used to describe these have common usage that is different than
+ the standards usage of this memo. In order to reference, within this
+ memo, elements of the calendaring and scheduling model, core object
+ (this memo), or interoperability protocol [2446bis] some formatting
+ conventions have been used. Calendaring and scheduling roles are
+ referred to in quoted-strings of text with the first character of
+ each word in uppercase. For example, "Organizer" refers to a role of
+ a "Calendar User" within the scheduling protocol defined by
+ [2446bis]. Calendar components defined by this memo are referred to
+
+
+
+Desruisseaux Standards Track [Page 6]
+
+RFC 5545 iCalendar September 2009
+
+
+ with capitalized, quoted-strings of text. All calendar components
+ start with the letter "V". For example, "VEVENT" refers to the event
+ calendar component, "VTODO" refers to the to-do calendar component,
+ and "VJOURNAL" refers to the daily journal calendar component.
+ Scheduling methods defined by iTIP [2446bis] are referred to with
+ capitalized, quoted-strings of text. For example, "REQUEST" refers
+ to the method for requesting a scheduling calendar component be
+ created or modified, and "REPLY" refers to the method a recipient of
+ a request uses to update their status with the "Organizer" of the
+ calendar component.
+
+ The properties defined by this memo are referred to with capitalized,
+ quoted-strings of text, followed by the word "property". For
+ example, "ATTENDEE" property refers to the iCalendar property used to
+ convey the calendar address of a calendar user. Property parameters
+ defined by this memo are referred to with lowercase, quoted-strings
+ of text, followed by the word "parameter". For example, "value"
+ parameter refers to the iCalendar property parameter used to override
+ the default value type for a property value. Enumerated values
+ defined by this memo are referred to with capitalized text, either
+ alone or followed by the word "value". For example, the "MINUTELY"
+ value can be used with the "FREQ" component of the "RECUR" value type
+ to specify repeating components based on an interval of one minute or
+ more.
+
+ The following table lists the different characters from the
+ [US-ASCII] character set that is referenced in this document. For
+ each character, the table specifies the character name used
+ throughout this document, along with its US-ASCII decimal codepoint.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 7]
+
+RFC 5545 iCalendar September 2009
+
+
+ +------------------------+-------------------+
+ | Character name | Decimal codepoint |
+ +------------------------+-------------------+
+ | HTAB | 9 |
+ | LF | 10 |
+ | CR | 13 |
+ | DQUOTE | 22 |
+ | SPACE | 32 |
+ | PLUS SIGN | 43 |
+ | COMMA | 44 |
+ | HYPHEN-MINUS | 45 |
+ | PERIOD | 46 |
+ | SOLIDUS | 47 |
+ | COLON | 58 |
+ | SEMICOLON | 59 |
+ | LATIN CAPITAL LETTER N | 78 |
+ | LATIN CAPITAL LETTER T | 84 |
+ | LATIN CAPITAL LETTER X | 88 |
+ | LATIN CAPITAL LETTER Z | 90 |
+ | BACKSLASH | 92 |
+ | LATIN SMALL LETTER N | 110 |
+ +------------------------+-------------------+
+
+2.2. Related Memos
+
+ Implementers will need to be familiar with several other memos that,
+ along with this memo, form a framework for Internet calendaring and
+ scheduling standards. This memo specifies a core specification of
+ objects, value types, properties, and property parameters.
+
+ o iTIP [2446bis] specifies an interoperability protocol for
+ scheduling between different implementations;
+
+ o iCalendar Message-Based Interoperability Protocol (iMIP) [2447bis]
+ specifies an Internet email binding for [2446bis].
+
+ This memo does not attempt to repeat the specification of concepts or
+ definitions from these other memos. Where possible, references are
+ made to the memo that provides for the specification of these
+ concepts or definitions.
+
+3. iCalendar Object Specification
+
+ The following sections define the details of a Calendaring and
+ Scheduling Core Object Specification. The Calendaring and Scheduling
+ Core Object is a collection of calendaring and scheduling
+ information. Typically, this information will consist of an
+ iCalendar stream with one or more iCalendar objects. The body of the
+
+
+
+Desruisseaux Standards Track [Page 8]
+
+RFC 5545 iCalendar September 2009
+
+
+ iCalendar object consists of a sequence of calendar properties and
+ one or more calendar components.
+
+ Section 3.1 defines the content line format; Section 3.2 defines the
+ property parameter format; Section 3.3 defines the data types for
+ property values; Section 3.4 defines the iCalendar object format;
+ Section 3.5 defines the iCalendar property format; Section 3.6
+ defines the calendar component format; Section 3.7 defines calendar
+ properties; and Section 3.8 defines calendar component properties.
+
+ This information is intended to be an integral part of the MIME
+ content type registration. In addition, this information can be used
+ independent of such content registration. In particular, this memo
+ has direct applicability for use as a calendaring and scheduling
+ exchange format in file-, memory-, or network-based transport
+ mechanisms.
+
+3.1. Content Lines
+
+ The iCalendar object is organized into individual lines of text,
+ called content lines. Content lines are delimited by a line break,
+ which is a CRLF sequence (CR character followed by LF character).
+
+ Lines of text SHOULD NOT be longer than 75 octets, excluding the line
+ break. Long content lines SHOULD be split into a multiple line
+ representations using a line "folding" technique. That is, a long
+ line can be split between any two characters by inserting a CRLF
+ immediately followed by a single linear white-space character (i.e.,
+ SPACE or HTAB). Any sequence of CRLF followed immediately by a
+ single linear white-space character is ignored (i.e., removed) when
+ processing the content type.
+
+ For example, the line:
+
+ DESCRIPTION:This is a long description that exists on a long line.
+
+ Can be represented as:
+
+ DESCRIPTION:This is a lo
+ ng description
+ that exists on a long line.
+
+ The process of moving from this folded multiple-line representation
+ to its single-line representation is called "unfolding". Unfolding
+ is accomplished by removing the CRLF and the linear white-space
+ character that immediately follows.
+
+
+
+
+
+Desruisseaux Standards Track [Page 9]
+
+RFC 5545 iCalendar September 2009
+
+
+ When parsing a content line, folded lines MUST first be unfolded
+ according to the unfolding procedure described above.
+
+ Note: It is possible for very simple implementations to generate
+ improperly folded lines in the middle of a UTF-8 multi-octet
+ sequence. For this reason, implementations need to unfold lines
+ in such a way to properly restore the original sequence.
+
+ The content information associated with an iCalendar object is
+ formatted using a syntax similar to that defined by [RFC2425]. That
+ is, the content information consists of CRLF-separated content lines.
+
+ The following notation defines the lines of content in an iCalendar
+ object:
+
+ contentline = name *(";" param ) ":" value CRLF
+ ; This ABNF is just a general definition for an initial parsing
+ ; of the content line into its property name, parameter list,
+ ; and value string
+
+ ; When parsing a content line, folded lines MUST first
+ ; be unfolded according to the unfolding procedure
+ ; described above. When generating a content line, lines
+ ; longer than 75 octets SHOULD be folded according to
+ ; the folding procedure described above.
+
+ name = iana-token / x-name
+
+ iana-token = 1*(ALPHA / DIGIT / "-")
+ ; iCalendar identifier registered with IANA
+
+ x-name = "X-" [vendorid "-"] 1*(ALPHA / DIGIT / "-")
+ ; Reserved for experimental use.
+
+ vendorid = 3*(ALPHA / DIGIT)
+ ; Vendor identification
+
+ param = param-name "=" param-value *("," param-value)
+ ; Each property defines the specific ABNF for the parameters
+ ; allowed on the property. Refer to specific properties for
+ ; precise parameter ABNF.
+
+ param-name = iana-token / x-name
+
+ param-value = paramtext / quoted-string
+
+ paramtext = *SAFE-CHAR
+
+
+
+
+Desruisseaux Standards Track [Page 10]
+
+RFC 5545 iCalendar September 2009
+
+
+ value = *VALUE-CHAR
+
+ quoted-string = DQUOTE *QSAFE-CHAR DQUOTE
+
+ QSAFE-CHAR = WSP / %x21 / %x23-7E / NON-US-ASCII
+ ; Any character except CONTROL and DQUOTE
+
+ SAFE-CHAR = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-7E
+ / NON-US-ASCII
+ ; Any character except CONTROL, DQUOTE, ";", ":", ","
+
+ VALUE-CHAR = WSP / %x21-7E / NON-US-ASCII
+ ; Any textual character
+
+ NON-US-ASCII = UTF8-2 / UTF8-3 / UTF8-4
+ ; UTF8-2, UTF8-3, and UTF8-4 are defined in [RFC3629]
+
+ CONTROL = %x00-08 / %x0A-1F / %x7F
+ ; All the controls except HTAB
+
+ The property value component of a content line has a format that is
+ property specific. Refer to the section describing each property for
+ a definition of this format.
+
+ All names of properties, property parameters, enumerated property
+ values and property parameter values are case-insensitive. However,
+ all other property values are case-sensitive, unless otherwise
+ stated.
+
+3.1.1. List and Field Separators
+
+ Some properties and parameters allow a list of values. Values in a
+ list of values MUST be separated by a COMMA character. There is no
+ significance to the order of values in a list. For those parameter
+ values (such as those that specify URI values) that are specified in
+ quoted-strings, the individual quoted-strings are separated by a
+ COMMA character.
+
+ Some property values are defined in terms of multiple parts. These
+ structured property values MUST have their value parts separated by a
+ SEMICOLON character.
+
+ Some properties allow a list of parameters. Each property parameter
+ in a list of property parameters MUST be separated by a SEMICOLON
+ character.
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 11]
+
+RFC 5545 iCalendar September 2009
+
+
+ Property parameters with values containing a COLON character, a
+ SEMICOLON character or a COMMA character MUST be placed in quoted
+ text.
+
+ For example, in the following properties, a SEMICOLON is used to
+ separate property parameters from each other and a COMMA character is
+ used to separate property values in a value list.
+
+ ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT:mailto:
+ jsmith@example.com
+
+ RDATE;VALUE=DATE:19970304,19970504,19970704,19970904
+
+3.1.2. Multiple Values
+
+ Some properties defined in the iCalendar object can have multiple
+ values. The general rule for encoding multi-valued items is to
+ simply create a new content line for each value, including the
+ property name. However, it should be noted that some properties
+ support encoding multiple values in a single property by separating
+ the values with a COMMA character. Individual property definitions
+ should be consulted for determining whether a specific property
+ allows multiple values and in which of these two forms. Multi-valued
+ properties MUST NOT be used to specify multiple language variants of
+ the same value. Calendar applications SHOULD display all values.
+
+3.1.3. Binary Content
+
+ Binary content information in an iCalendar object SHOULD be
+ referenced using a URI within a property value. That is, the binary
+ content information SHOULD be placed in an external MIME entity that
+ can be referenced by a URI from within the iCalendar object. In
+ applications where this is not feasible, binary content information
+ can be included within an iCalendar object, but only after first
+ encoding it into text using the "BASE64" encoding method defined in
+ [RFC4648]. Inline binary content SHOULD only be used in applications
+ whose special circumstances demand that an iCalendar object be
+ expressed as a single entity. A property containing inline binary
+ content information MUST specify the "ENCODING" property parameter.
+ Binary content information placed external to the iCalendar object
+ MUST be referenced by a uniform resource identifier (URI).
+
+ The following example specifies an "ATTACH" property that references
+ an attachment external to the iCalendar object with a URI reference:
+
+ ATTACH:http://example.com/public/quarterly-report.doc
+
+
+
+
+
+Desruisseaux Standards Track [Page 12]
+
+RFC 5545 iCalendar September 2009
+
+
+ The following example specifies an "ATTACH" property with inline
+ binary encoded content information:
+
+ ATTACH;FMTTYPE=text/plain;ENCODING=BASE64;VALUE=BINARY:VGhlIH
+ F1aWNrIGJyb3duIGZveCBqdW1wcyBvdmVyIHRoZSBsYXp5IGRvZy4
+
+3.1.4. Character Set
+
+ There is not a property parameter to declare the charset used in a
+ property value. The default charset for an iCalendar stream is UTF-8
+ as defined in [RFC3629].
+
+ The "charset" Content-Type parameter MUST be used in MIME transports
+ to specify the charset being used.
+
+3.2. Property Parameters
+
+ A property can have attributes with which it is associated. These
+ "property parameters" contain meta-information about the property or
+ the property value. Property parameters are provided to specify such
+ information as the location of an alternate text representation for a
+ property value, the language of a text property value, the value type
+ of the property value, and other attributes.
+
+ Property parameter values that contain the COLON, SEMICOLON, or COMMA
+ character separators MUST be specified as quoted-string text values.
+ Property parameter values MUST NOT contain the DQUOTE character. The
+ DQUOTE character is used as a delimiter for parameter values that
+ contain restricted characters or URI text. For example:
+
+ DESCRIPTION;ALTREP="cid:part1.0001@example.org":The Fall'98 Wild
+ Wizards Conference - - Las Vegas\, NV\, USA
+
+ Property parameter values that are not in quoted-strings are case-
+ insensitive.
+
+ The general property parameters defined by this memo are defined by
+ the following notation:
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 13]
+
+RFC 5545 iCalendar September 2009
+
+
+ icalparameter = altrepparam ; Alternate text representation
+ / cnparam ; Common name
+ / cutypeparam ; Calendar user type
+ / delfromparam ; Delegator
+ / deltoparam ; Delegatee
+ / dirparam ; Directory entry
+ / encodingparam ; Inline encoding
+ / fmttypeparam ; Format type
+ / fbtypeparam ; Free/busy time type
+ / languageparam ; Language for text
+ / memberparam ; Group or list membership
+ / partstatparam ; Participation status
+ / rangeparam ; Recurrence identifier range
+ / trigrelparam ; Alarm trigger relationship
+ / reltypeparam ; Relationship type
+ / roleparam ; Participation role
+ / rsvpparam ; RSVP expectation
+ / sentbyparam ; Sent by
+ / tzidparam ; Reference to time zone object
+ / valuetypeparam ; Property value data type
+ / other-param
+
+ other-param = (iana-param / x-param)
+
+ iana-param = iana-token "=" param-value *("," param-value)
+ ; Some other IANA-registered iCalendar parameter.
+
+ x-param = x-name "=" param-value *("," param-value)
+ ; A non-standard, experimental parameter.
+
+ Applications MUST ignore x-param and iana-param values they don't
+ recognize.
+
+3.2.1. Alternate Text Representation
+
+ Parameter Name: ALTREP
+
+ Purpose: To specify an alternate text representation for the
+ property value.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ altrepparam = "ALTREP" "=" DQUOTE uri DQUOTE
+
+ Description: This parameter specifies a URI that points to an
+ alternate representation for a textual property value. A property
+ specifying this parameter MUST also include a value that reflects
+
+
+
+Desruisseaux Standards Track [Page 14]
+
+RFC 5545 iCalendar September 2009
+
+
+ the default representation of the text value. The URI parameter
+ value MUST be specified in a quoted-string.
+
+ Note: While there is no restriction imposed on the URI schemes
+ allowed for this parameter, Content Identifier (CID) [RFC2392],
+ HTTP [RFC2616], and HTTPS [RFC2818] are the URI schemes most
+ commonly used by current implementations.
+
+ Example:
+
+ DESCRIPTION;ALTREP="CID:part3.msg.970415T083000@example.com":
+ Project XYZ Review Meeting will include the following agenda
+ items: (a) Market Overview\, (b) Finances\, (c) Project Man
+ agement
+
+ The "ALTREP" property parameter value might point to a "text/html"
+ content portion.
+
+ Content-Type:text/html
+ Content-Id:<part3.msg.970415T083000@example.com>
+
+ <html>
+ <head>
+ <title></title>
+ </head>
+ <body>
+ <p>
+ <b>Project XYZ Review Meeting</b> will include
+ the following agenda items:
+ <ol>
+ <li>Market Overview</li>
+ <li>Finances</li>
+ <li>Project Management</li>
+ </ol>
+ </p>
+ </body>
+ </html>
+
+3.2.2. Common Name
+
+ Parameter Name: CN
+
+ Purpose: To specify the common name to be associated with the
+ calendar user specified by the property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+
+
+
+Desruisseaux Standards Track [Page 15]
+
+RFC 5545 iCalendar September 2009
+
+
+ cnparam = "CN" "=" param-value
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. The parameter specifies the common name
+ to be associated with the calendar user specified by the property.
+ The parameter value is text. The parameter value can be used for
+ display text to be associated with the calendar address specified
+ by the property.
+
+ Example:
+
+ ORGANIZER;CN="John Smith":mailto:jsmith@example.com
+
+3.2.3. Calendar User Type
+
+ Parameter Name: CUTYPE
+
+ Purpose: To identify the type of calendar user specified by the
+ property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ cutypeparam = "CUTYPE" "="
+ ("INDIVIDUAL" ; An individual
+ / "GROUP" ; A group of individuals
+ / "RESOURCE" ; A physical resource
+ / "ROOM" ; A room resource
+ / "UNKNOWN" ; Otherwise not known
+ / x-name ; Experimental type
+ / iana-token) ; Other IANA-registered
+ ; type
+ ; Default is INDIVIDUAL
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. The parameter identifies the type of
+ calendar user specified by the property. If not specified on a
+ property that allows this parameter, the default is INDIVIDUAL.
+ Applications MUST treat x-name and iana-token values they don't
+ recognize the same way as they would the UNKNOWN value.
+
+ Example:
+
+ ATTENDEE;CUTYPE=GROUP:mailto:ietf-calsch@example.org
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 16]
+
+RFC 5545 iCalendar September 2009
+
+
+3.2.4. Delegators
+
+ Parameter Name: DELEGATED-FROM
+
+ Purpose: To specify the calendar users that have delegated their
+ participation to the calendar user specified by the property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ delfromparam = "DELEGATED-FROM" "=" DQUOTE cal-address
+ DQUOTE *("," DQUOTE cal-address DQUOTE)
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. This parameter specifies those calendar
+ users that have delegated their participation in a group-scheduled
+ event or to-do to the calendar user specified by the property.
+ The individual calendar address parameter values MUST each be
+ specified in a quoted-string.
+
+ Example:
+
+ ATTENDEE;DELEGATED-FROM="mailto:jsmith@example.com":mailto:
+ jdoe@example.com
+
+3.2.5. Delegatees
+
+ Parameter Name: DELEGATED-TO
+
+ Purpose: To specify the calendar users to whom the calendar user
+ specified by the property has delegated participation.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ deltoparam = "DELEGATED-TO" "=" DQUOTE cal-address DQUOTE
+ *("," DQUOTE cal-address DQUOTE)
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. This parameter specifies those calendar
+ users whom have been delegated participation in a group-scheduled
+ event or to-do by the calendar user specified by the property.
+ The individual calendar address parameter values MUST each be
+ specified in a quoted-string.
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 17]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example:
+
+ ATTENDEE;DELEGATED-TO="mailto:jdoe@example.com","mailto:jqpublic
+ @example.com":mailto:jsmith@example.com
+
+3.2.6. Directory Entry Reference
+
+ Parameter Name: DIR
+
+ Purpose: To specify reference to a directory entry associated with
+ the calendar user specified by the property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ dirparam = "DIR" "=" DQUOTE uri DQUOTE
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. The parameter specifies a reference to
+ the directory entry associated with the calendar user specified by
+ the property. The parameter value is a URI. The URI parameter
+ value MUST be specified in a quoted-string.
+
+ Note: While there is no restriction imposed on the URI schemes
+ allowed for this parameter, CID [RFC2392], DATA [RFC2397], FILE
+ [RFC1738], FTP [RFC1738], HTTP [RFC2616], HTTPS [RFC2818], LDAP
+ [RFC4516], and MID [RFC2392] are the URI schemes most commonly
+ used by current implementations.
+
+ Example:
+
+ ORGANIZER;DIR="ldap://example.com:6666/o=ABC%20Industries,
+ c=US???(cn=Jim%20Dolittle)":mailto:jimdo@example.com
+
+3.2.7. Inline Encoding
+
+ Parameter Name: ENCODING
+
+ Purpose: To specify an alternate inline encoding for the property
+ value.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 18]
+
+RFC 5545 iCalendar September 2009
+
+
+ encodingparam = "ENCODING" "="
+ ( "8BIT"
+ ; "8bit" text encoding is defined in [RFC2045]
+ / "BASE64"
+ ; "BASE64" binary encoding format is defined in [RFC4648]
+ )
+
+ Description: This property parameter identifies the inline encoding
+ used in a property value. The default encoding is "8BIT",
+ corresponding to a property value consisting of text. The
+ "BASE64" encoding type corresponds to a property value encoded
+ using the "BASE64" encoding defined in [RFC2045].
+
+ If the value type parameter is ";VALUE=BINARY", then the inline
+ encoding parameter MUST be specified with the value
+ ";ENCODING=BASE64".
+
+ Example:
+
+ ATTACH;FMTTYPE=text/plain;ENCODING=BASE64;VALUE=BINARY:TG9yZW
+ 0gaXBzdW0gZG9sb3Igc2l0IGFtZXQsIGNvbnNlY3RldHVyIGFkaXBpc2ljaW
+ 5nIGVsaXQsIHNlZCBkbyBlaXVzbW9kIHRlbXBvciBpbmNpZGlkdW50IHV0IG
+ xhYm9yZSBldCBkb2xvcmUgbWFnbmEgYWxpcXVhLiBVdCBlbmltIGFkIG1pbm
+ ltIHZlbmlhbSwgcXVpcyBub3N0cnVkIGV4ZXJjaXRhdGlvbiB1bGxhbWNvIG
+ xhYm9yaXMgbmlzaSB1dCBhbGlxdWlwIGV4IGVhIGNvbW1vZG8gY29uc2VxdW
+ F0LiBEdWlzIGF1dGUgaXJ1cmUgZG9sb3IgaW4gcmVwcmVoZW5kZXJpdCBpbi
+ B2b2x1cHRhdGUgdmVsaXQgZXNzZSBjaWxsdW0gZG9sb3JlIGV1IGZ1Z2lhdC
+ BudWxsYSBwYXJpYXR1ci4gRXhjZXB0ZXVyIHNpbnQgb2NjYWVjYXQgY3VwaW
+ RhdGF0IG5vbiBwcm9pZGVudCwgc3VudCBpbiBjdWxwYSBxdWkgb2ZmaWNpYS
+ BkZXNlcnVudCBtb2xsaXQgYW5pbSBpZCBlc3QgbGFib3J1bS4=
+
+3.2.8. Format Type
+
+ Parameter Name: FMTTYPE
+
+ Purpose: To specify the content type of a referenced object.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ fmttypeparam = "FMTTYPE" "=" type-name "/" subtype-name
+ ; Where "type-name" and "subtype-name" are
+ ; defined in Section 4.2 of [RFC4288].
+
+ Description: This parameter can be specified on properties that are
+ used to reference an object. The parameter specifies the media
+ type [RFC4288] of the referenced object. For example, on the
+ "ATTACH" property, an FTP type URI value does not, by itself,
+
+
+
+Desruisseaux Standards Track [Page 19]
+
+RFC 5545 iCalendar September 2009
+
+
+ necessarily convey the type of content associated with the
+ resource. The parameter value MUST be the text for either an
+ IANA-registered media type or a non-standard media type.
+
+ Example:
+
+ ATTACH;FMTTYPE=application/msword:ftp://example.com/pub/docs/
+ agenda.doc
+
+3.2.9. Free/Busy Time Type
+
+ Parameter Name: FBTYPE
+
+ Purpose: To specify the free or busy time type.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ fbtypeparam = "FBTYPE" "=" ("FREE" / "BUSY"
+ / "BUSY-UNAVAILABLE" / "BUSY-TENTATIVE"
+ / x-name
+ ; Some experimental iCalendar free/busy type.
+ / iana-token)
+ ; Some other IANA-registered iCalendar free/busy type.
+
+ Description: This parameter specifies the free or busy time type.
+ The value FREE indicates that the time interval is free for
+ scheduling. The value BUSY indicates that the time interval is
+ busy because one or more events have been scheduled for that
+ interval. The value BUSY-UNAVAILABLE indicates that the time
+ interval is busy and that the interval can not be scheduled. The
+ value BUSY-TENTATIVE indicates that the time interval is busy
+ because one or more events have been tentatively scheduled for
+ that interval. If not specified on a property that allows this
+ parameter, the default is BUSY. Applications MUST treat x-name
+ and iana-token values they don't recognize the same way as they
+ would the BUSY value.
+
+ Example: The following is an example of this parameter on a
+ "FREEBUSY" property.
+
+ FREEBUSY;FBTYPE=BUSY:19980415T133000Z/19980415T170000Z
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 20]
+
+RFC 5545 iCalendar September 2009
+
+
+3.2.10. Language
+
+ Parameter Name: LANGUAGE
+
+ Purpose: To specify the language for text values in a property or
+ property parameter.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ languageparam = "LANGUAGE" "=" language
+
+ language = Language-Tag
+ ; As defined in [RFC5646].
+
+ Description: This parameter identifies the language of the text in
+ the property value and of all property parameter values of the
+ property. The value of the "LANGUAGE" property parameter is that
+ defined in [RFC5646].
+
+ For transport in a MIME entity, the Content-Language header field
+ can be used to set the default language for the entire body part.
+ Otherwise, no default language is assumed.
+
+ Example: The following are examples of this parameter on the
+ "SUMMARY" and "LOCATION" properties:
+
+ SUMMARY;LANGUAGE=en-US:Company Holiday Party
+
+ LOCATION;LANGUAGE=en:Germany
+
+ LOCATION;LANGUAGE=no:Tyskland
+
+3.2.11. Group or List Membership
+
+ Parameter Name: MEMBER
+
+ Purpose: To specify the group or list membership of the calendar
+ user specified by the property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ memberparam = "MEMBER" "=" DQUOTE cal-address DQUOTE
+ *("," DQUOTE cal-address DQUOTE)
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 21]
+
+RFC 5545 iCalendar September 2009
+
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. The parameter identifies the groups or
+ list membership for the calendar user specified by the property.
+ The parameter value is either a single calendar address in a
+ quoted-string or a COMMA-separated list of calendar addresses,
+ each in a quoted-string. The individual calendar address
+ parameter values MUST each be specified in a quoted-string.
+
+ Example:
+
+ ATTENDEE;MEMBER="mailto:ietf-calsch@example.org":mailto:
+ jsmith@example.com
+
+ ATTENDEE;MEMBER="mailto:projectA@example.com","mailto:pr
+ ojectB@example.com":mailto:janedoe@example.com
+
+3.2.12. Participation Status
+
+ Parameter Name: PARTSTAT
+
+ Purpose: To specify the participation status for the calendar user
+ specified by the property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ partstatparam = "PARTSTAT" "="
+ (partstat-event
+ / partstat-todo
+ / partstat-jour)
+
+ partstat-event = ("NEEDS-ACTION" ; Event needs action
+ / "ACCEPTED" ; Event accepted
+ / "DECLINED" ; Event declined
+ / "TENTATIVE" ; Event tentatively
+ ; accepted
+ / "DELEGATED" ; Event delegated
+ / x-name ; Experimental status
+ / iana-token) ; Other IANA-registered
+ ; status
+ ; These are the participation statuses for a "VEVENT".
+ ; Default is NEEDS-ACTION.
+
+ partstat-todo = ("NEEDS-ACTION" ; To-do needs action
+ / "ACCEPTED" ; To-do accepted
+ / "DECLINED" ; To-do declined
+ / "TENTATIVE" ; To-do tentatively
+ ; accepted
+
+
+
+Desruisseaux Standards Track [Page 22]
+
+RFC 5545 iCalendar September 2009
+
+
+ / "DELEGATED" ; To-do delegated
+ / "COMPLETED" ; To-do completed
+ ; COMPLETED property has
+ ; DATE-TIME completed
+ / "IN-PROCESS" ; To-do in process of
+ ; being completed
+ / x-name ; Experimental status
+ / iana-token) ; Other IANA-registered
+ ; status
+ ; These are the participation statuses for a "VTODO".
+ ; Default is NEEDS-ACTION.
+
+
+
+ partstat-jour = ("NEEDS-ACTION" ; Journal needs action
+ / "ACCEPTED" ; Journal accepted
+ / "DECLINED" ; Journal declined
+ / x-name ; Experimental status
+ / iana-token) ; Other IANA-registered
+ ; status
+ ; These are the participation statuses for a "VJOURNAL".
+ ; Default is NEEDS-ACTION.
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. The parameter identifies the
+ participation status for the calendar user specified by the
+ property value. The parameter values differ depending on whether
+ they are associated with a group-scheduled "VEVENT", "VTODO", or
+ "VJOURNAL". The values MUST match one of the values allowed for
+ the given calendar component. If not specified on a property that
+ allows this parameter, the default value is NEEDS-ACTION.
+ Applications MUST treat x-name and iana-token values they don't
+ recognize the same way as they would the NEEDS-ACTION value.
+
+ Example:
+
+ ATTENDEE;PARTSTAT=DECLINED:mailto:jsmith@example.com
+
+3.2.13. Recurrence Identifier Range
+
+ Parameter Name: RANGE
+
+ Purpose: To specify the effective range of recurrence instances from
+ the instance specified by the recurrence identifier specified by
+ the property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+
+
+Desruisseaux Standards Track [Page 23]
+
+RFC 5545 iCalendar September 2009
+
+
+ rangeparam = "RANGE" "=" "THISANDFUTURE"
+ ; To specify the instance specified by the recurrence identifier
+ ; and all subsequent recurrence instances.
+
+ Description: This parameter can be specified on a property that
+ specifies a recurrence identifier. The parameter specifies the
+ effective range of recurrence instances that is specified by the
+ property. The effective range is from the recurrence identifier
+ specified by the property. If this parameter is not specified on
+ an allowed property, then the default range is the single instance
+ specified by the recurrence identifier value of the property. The
+ parameter value can only be "THISANDFUTURE" to indicate a range
+ defined by the recurrence identifier and all subsequent instances.
+ The value "THISANDPRIOR" is deprecated by this revision of
+ iCalendar and MUST NOT be generated by applications.
+
+ Example:
+
+ RECURRENCE-ID;RANGE=THISANDFUTURE:19980401T133000Z
+
+3.2.14. Alarm Trigger Relationship
+
+ Parameter Name: RELATED
+
+ Purpose: To specify the relationship of the alarm trigger with
+ respect to the start or end of the calendar component.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ trigrelparam = "RELATED" "="
+ ("START" ; Trigger off of start
+ / "END") ; Trigger off of end
+
+ Description: This parameter can be specified on properties that
+ specify an alarm trigger with a "DURATION" value type. The
+ parameter specifies whether the alarm will trigger relative to the
+ start or end of the calendar component. The parameter value START
+ will set the alarm to trigger off the start of the calendar
+ component; the parameter value END will set the alarm to trigger
+ off the end of the calendar component. If the parameter is not
+ specified on an allowable property, then the default is START.
+
+ Example:
+
+ TRIGGER;RELATED=END:PT5M
+
+
+
+
+
+Desruisseaux Standards Track [Page 24]
+
+RFC 5545 iCalendar September 2009
+
+
+3.2.15. Relationship Type
+
+ Parameter Name: RELTYPE
+
+ Purpose: To specify the type of hierarchical relationship associated
+ with the calendar component specified by the property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ reltypeparam = "RELTYPE" "="
+ ("PARENT" ; Parent relationship - Default
+ / "CHILD" ; Child relationship
+ / "SIBLING" ; Sibling relationship
+ / iana-token ; Some other IANA-registered
+ ; iCalendar relationship type
+ / x-name) ; A non-standard, experimental
+ ; relationship type
+
+ Description: This parameter can be specified on a property that
+ references another related calendar. The parameter specifies the
+ hierarchical relationship type of the calendar component
+ referenced by the property. The parameter value can be PARENT, to
+ indicate that the referenced calendar component is a superior of
+ calendar component; CHILD to indicate that the referenced calendar
+ component is a subordinate of the calendar component; or SIBLING
+ to indicate that the referenced calendar component is a peer of
+ the calendar component. If this parameter is not specified on an
+ allowable property, the default relationship type is PARENT.
+ Applications MUST treat x-name and iana-token values they don't
+ recognize the same way as they would the PARENT value.
+
+ Example:
+
+ RELATED-TO;RELTYPE=SIBLING:19960401-080045-4000F192713@
+ example.com
+
+3.2.16. Participation Role
+
+ Parameter Name: ROLE
+
+ Purpose: To specify the participation role for the calendar user
+ specified by the property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+
+
+
+
+Desruisseaux Standards Track [Page 25]
+
+RFC 5545 iCalendar September 2009
+
+
+ roleparam = "ROLE" "="
+ ("CHAIR" ; Indicates chair of the
+ ; calendar entity
+ / "REQ-PARTICIPANT" ; Indicates a participant whose
+ ; participation is required
+ / "OPT-PARTICIPANT" ; Indicates a participant whose
+ ; participation is optional
+ / "NON-PARTICIPANT" ; Indicates a participant who
+ ; is copied for information
+ ; purposes only
+ / x-name ; Experimental role
+ / iana-token) ; Other IANA role
+ ; Default is REQ-PARTICIPANT
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. The parameter specifies the participation
+ role for the calendar user specified by the property in the group
+ schedule calendar component. If not specified on a property that
+ allows this parameter, the default value is REQ-PARTICIPANT.
+ Applications MUST treat x-name and iana-token values they don't
+ recognize the same way as they would the REQ-PARTICIPANT value.
+
+ Example:
+
+ ATTENDEE;ROLE=CHAIR:mailto:mrbig@example.com
+
+3.2.17. RSVP Expectation
+
+ Parameter Name: RSVP
+
+ Purpose: To specify whether there is an expectation of a favor of a
+ reply from the calendar user specified by the property value.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ rsvpparam = "RSVP" "=" ("TRUE" / "FALSE")
+ ; Default is FALSE
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. The parameter identifies the expectation
+ of a reply from the calendar user specified by the property value.
+ This parameter is used by the "Organizer" to request a
+ participation status reply from an "Attendee" of a group-scheduled
+ event or to-do. If not specified on a property that allows this
+ parameter, the default value is FALSE.
+
+
+
+
+
+Desruisseaux Standards Track [Page 26]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example:
+
+ ATTENDEE;RSVP=TRUE:mailto:jsmith@example.com
+
+3.2.18. Sent By
+
+ Parameter Name: SENT-BY
+
+ Purpose: To specify the calendar user that is acting on behalf of
+ the calendar user specified by the property.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ sentbyparam = "SENT-BY" "=" DQUOTE cal-address DQUOTE
+
+ Description: This parameter can be specified on properties with a
+ CAL-ADDRESS value type. The parameter specifies the calendar user
+ that is acting on behalf of the calendar user specified by the
+ property. The parameter value MUST be a mailto URI as defined in
+ [RFC2368]. The individual calendar address parameter values MUST
+ each be specified in a quoted-string.
+
+ Example:
+
+ ORGANIZER;SENT-BY="mailto:sray@example.com":mailto:
+ jsmith@example.com
+
+3.2.19. Time Zone Identifier
+
+ Parameter Name: TZID
+
+ Purpose: To specify the identifier for the time zone definition for
+ a time component in the property value.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ tzidparam = "TZID" "=" [tzidprefix] paramtext
+
+ tzidprefix = "/"
+
+ Description: This parameter MUST be specified on the "DTSTART",
+ "DTEND", "DUE", "EXDATE", and "RDATE" properties when either a
+ DATE-TIME or TIME value type is specified and when the value is
+ neither a UTC or a "floating" time. Refer to the DATE-TIME or
+ TIME value type definition for a description of UTC and "floating
+ time" formats. This property parameter specifies a text value
+
+
+
+Desruisseaux Standards Track [Page 27]
+
+RFC 5545 iCalendar September 2009
+
+
+ that uniquely identifies the "VTIMEZONE" calendar component to be
+ used when evaluating the time portion of the property. The value
+ of the "TZID" property parameter will be equal to the value of the
+ "TZID" property for the matching time zone definition. An
+ individual "VTIMEZONE" calendar component MUST be specified for
+ each unique "TZID" parameter value specified in the iCalendar
+ object.
+
+ The parameter MUST be specified on properties with a DATE-TIME
+ value if the DATE-TIME is not either a UTC or a "floating" time.
+ Failure to include and follow VTIMEZONE definitions in iCalendar
+ objects may lead to inconsistent understanding of the local time
+ at any given location.
+
+ The presence of the SOLIDUS character as a prefix, indicates that
+ this "TZID" represents a unique ID in a globally defined time zone
+ registry (when such registry is defined).
+
+ Note: This document does not define a naming convention for
+ time zone identifiers. Implementers may want to use the naming
+ conventions defined in existing time zone specifications such
+ as the public-domain TZ database [TZDB]. The specification of
+ globally unique time zone identifiers is not addressed by this
+ document and is left for future study.
+
+ The following are examples of this property parameter:
+
+ DTSTART;TZID=America/New_York:19980119T020000
+
+ DTEND;TZID=America/New_York:19980119T030000
+
+ The "TZID" property parameter MUST NOT be applied to DATE
+ properties and DATE-TIME or TIME properties whose time values are
+ specified in UTC.
+
+ The use of local time in a DATE-TIME or TIME value without the
+ "TZID" property parameter is to be interpreted as floating time,
+ regardless of the existence of "VTIMEZONE" calendar components in
+ the iCalendar object.
+
+ For more information, see the sections on the value types DATE-
+ TIME and TIME.
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 28]
+
+RFC 5545 iCalendar September 2009
+
+
+3.2.20. Value Data Types
+
+ Parameter Name: VALUE
+
+ Purpose: To explicitly specify the value type format for a property
+ value.
+
+ Format Definition: This property parameter is defined by the
+ following notation:
+
+ valuetypeparam = "VALUE" "=" valuetype
+
+ valuetype = ("BINARY"
+ / "BOOLEAN"
+ / "CAL-ADDRESS"
+ / "DATE"
+ / "DATE-TIME"
+ / "DURATION"
+ / "FLOAT"
+ / "INTEGER"
+ / "PERIOD"
+ / "RECUR"
+ / "TEXT"
+ / "TIME"
+ / "URI"
+ / "UTC-OFFSET"
+ / x-name
+ ; Some experimental iCalendar value type.
+ / iana-token)
+ ; Some other IANA-registered iCalendar value type.
+
+ Description: This parameter specifies the value type and format of
+ the property value. The property values MUST be of a single value
+ type. For example, a "RDATE" property cannot have a combination
+ of DATE-TIME and TIME value types.
+
+ If the property's value is the default value type, then this
+ parameter need not be specified. However, if the property's
+ default value type is overridden by some other allowable value
+ type, then this parameter MUST be specified.
+
+ Applications MUST preserve the value data for x-name and iana-
+ token values that they don't recognize without attempting to
+ interpret or parse the value data.
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 29]
+
+RFC 5545 iCalendar September 2009
+
+
+3.3. Property Value Data Types
+
+ The properties in an iCalendar object are strongly typed. The
+ definition of each property restricts the value to be one of the
+ value data types, or simply value types, defined in this section.
+ The value type for a property will either be specified implicitly as
+ the default value type or will be explicitly specified with the
+ "VALUE" parameter. If the value type of a property is one of the
+ alternate valid types, then it MUST be explicitly specified with the
+ "VALUE" parameter.
+
+3.3.1. Binary
+
+ Value Name: BINARY
+
+ Purpose: This value type is used to identify properties that contain
+ a character encoding of inline binary data. For example, an
+ inline attachment of a document might be included in an iCalendar
+ object.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ binary = *(4b-char) [b-end]
+ ; A "BASE64" encoded character string, as defined by [RFC4648].
+
+ b-end = (2b-char "==") / (3b-char "=")
+
+ b-char = ALPHA / DIGIT / "+" / "/"
+
+ Description: Property values with this value type MUST also include
+ the inline encoding parameter sequence of ";ENCODING=BASE64".
+ That is, all inline binary data MUST first be character encoded
+ using the "BASE64" encoding method defined in [RFC2045]. No
+ additional content value encoding (i.e., BACKSLASH character
+ encoding, see Section 3.3.11) is defined for this value type.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 30]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example: The following is an example of a "BASE64" encoded binary
+ value data:
+
+ ATTACH;FMTTYPE=image/vnd.microsoft.icon;ENCODING=BASE64;VALUE
+ =BINARY:AAABAAEAEBAQAAEABAAoAQAAFgAAACgAAAAQAAAAIAAAAAEABAAA
+ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAgIAAAICAgADAwMAA////AAAA
+ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+ AAAAAAAAAAAAAAAAAAAAAAMwAAAAAAABNEMQAAAAAAAkQgAAAAAAJEREQgAA
+ ACECQ0QgEgAAQxQzM0E0AABERCRCREQAADRDJEJEQwAAAhA0QwEQAAAAAERE
+ AAAAAAAAREQAAAAAAAAkQgAAAAAAAAMgAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+ AAAAAAAAAAAA
+
+3.3.2. Boolean
+
+ Value Name: BOOLEAN
+
+ Purpose: This value type is used to identify properties that contain
+ either a "TRUE" or "FALSE" Boolean value.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ boolean = "TRUE" / "FALSE"
+
+ Description: These values are case-insensitive text. No additional
+ content value encoding (i.e., BACKSLASH character encoding, see
+ Section 3.3.11) is defined for this value type.
+
+ Example: The following is an example of a hypothetical property that
+ has a BOOLEAN value type:
+
+ TRUE
+
+3.3.3. Calendar User Address
+
+ Value Name: CAL-ADDRESS
+
+ Purpose: This value type is used to identify properties that contain
+ a calendar user address.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ cal-address = uri
+
+ Description: The value is a URI as defined by [RFC3986] or any other
+ IANA-registered form for a URI. When used to address an Internet
+
+
+
+Desruisseaux Standards Track [Page 31]
+
+RFC 5545 iCalendar September 2009
+
+
+ email transport address for a calendar user, the value MUST be a
+ mailto URI, as defined by [RFC2368]. No additional content value
+ encoding (i.e., BACKSLASH character encoding, see Section 3.3.11)
+ is defined for this value type.
+
+ Example:
+
+ mailto:jane_doe@example.com
+
+3.3.4. Date
+
+ Value Name: DATE
+
+ Purpose: This value type is used to identify values that contain a
+ calendar date.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ date = date-value
+
+ date-value = date-fullyear date-month date-mday
+ date-fullyear = 4DIGIT
+ date-month = 2DIGIT ;01-12
+ date-mday = 2DIGIT ;01-28, 01-29, 01-30, 01-31
+ ;based on month/year
+
+ Description: If the property permits, multiple "date" values are
+ specified as a COMMA-separated list of values. The format for the
+ value type is based on the [ISO.8601.2004] complete
+ representation, basic format for a calendar date. The textual
+ format specifies a four-digit year, two-digit month, and two-digit
+ day of the month. There are no separator characters between the
+ year, month, and day component text.
+
+ No additional content value encoding (i.e., BACKSLASH character
+ encoding, see Section 3.3.11) is defined for this value type.
+
+ Example: The following represents July 14, 1997:
+
+ 19970714
+
+3.3.5. Date-Time
+
+ Value Name: DATE-TIME
+
+ Purpose: This value type is used to identify values that specify a
+ precise calendar date and time of day.
+
+
+
+Desruisseaux Standards Track [Page 32]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ date-time = date "T" time ;As specified in the DATE and TIME
+ ;value definitions
+
+ Description: If the property permits, multiple "DATE-TIME" values
+ are specified as a COMMA-separated list of values. No additional
+ content value encoding (i.e., BACKSLASH character encoding, see
+ Section 3.3.11) is defined for this value type.
+
+ The "DATE-TIME" value type is used to identify values that contain
+ a precise calendar date and time of day. The format is based on
+ the [ISO.8601.2004] complete representation, basic format for a
+ calendar date and time of day. The text format is a concatenation
+ of the "date", followed by the LATIN CAPITAL LETTER T character,
+ the time designator, followed by the "time" format.
+
+ The "DATE-TIME" value type expresses time values in three forms:
+
+ The form of date and time with UTC offset MUST NOT be used. For
+ example, the following is not valid for a DATE-TIME value:
+
+ 19980119T230000-0800 ;Invalid time format
+
+ FORM #1: DATE WITH LOCAL TIME
+
+ The date with local time form is simply a DATE-TIME value that
+ does not contain the UTC designator nor does it reference a time
+ zone. For example, the following represents January 18, 1998, at
+ 11 PM:
+
+ 19980118T230000
+
+ DATE-TIME values of this type are said to be "floating" and are
+ not bound to any time zone in particular. They are used to
+ represent the same hour, minute, and second value regardless of
+ which time zone is currently being observed. For example, an
+ event can be defined that indicates that an individual will be
+ busy from 11:00 AM to 1:00 PM every day, no matter which time zone
+ the person is in. In these cases, a local time can be specified.
+ The recipient of an iCalendar object with a property value
+ consisting of a local time, without any relative time zone
+ information, SHOULD interpret the value as being fixed to whatever
+ time zone the "ATTENDEE" is in at any given moment. This means
+ that two "Attendees", in different time zones, receiving the same
+ event definition as a floating time, may be participating in the
+
+
+
+
+Desruisseaux Standards Track [Page 33]
+
+RFC 5545 iCalendar September 2009
+
+
+ event at different actual times. Floating time SHOULD only be
+ used where that is the reasonable behavior.
+
+ In most cases, a fixed time is desired. To properly communicate a
+ fixed time in a property value, either UTC time or local time with
+ time zone reference MUST be specified.
+
+ The use of local time in a DATE-TIME value without the "TZID"
+ property parameter is to be interpreted as floating time,
+ regardless of the existence of "VTIMEZONE" calendar components in
+ the iCalendar object.
+
+ FORM #2: DATE WITH UTC TIME
+
+ The date with UTC time, or absolute time, is identified by a LATIN
+ CAPITAL LETTER Z suffix character, the UTC designator, appended to
+ the time value. For example, the following represents January 19,
+ 1998, at 0700 UTC:
+
+ 19980119T070000Z
+
+ The "TZID" property parameter MUST NOT be applied to DATE-TIME
+ properties whose time values are specified in UTC.
+
+ FORM #3: DATE WITH LOCAL TIME AND TIME ZONE REFERENCE
+
+ The date and local time with reference to time zone information is
+ identified by the use the "TZID" property parameter to reference
+ the appropriate time zone definition. "TZID" is discussed in
+ detail in Section 3.2.19. For example, the following represents
+ 2:00 A.M. in New York on January 19, 1998:
+
+ TZID=America/New_York:19980119T020000
+
+ If, based on the definition of the referenced time zone, the local
+ time described occurs more than once (when changing from daylight
+ to standard time), the DATE-TIME value refers to the first
+ occurrence of the referenced time. Thus, TZID=America/
+ New_York:20071104T013000 indicates November 4, 2007 at 1:30 A.M.
+ EDT (UTC-04:00). If the local time described does not occur (when
+ changing from standard to daylight time), the DATE-TIME value is
+ interpreted using the UTC offset before the gap in local times.
+ Thus, TZID=America/New_York:20070311T023000 indicates March 11,
+ 2007 at 3:30 A.M. EDT (UTC-04:00), one hour after 1:30 A.M. EST
+ (UTC-05:00).
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 34]
+
+RFC 5545 iCalendar September 2009
+
+
+ A time value MUST only specify the second 60 when specifying a
+ positive leap second. For example:
+
+ 19970630T235960Z
+
+ Implementations that do not support leap seconds SHOULD interpret
+ the second 60 as equivalent to the second 59.
+
+ Example: The following represents July 14, 1997, at 1:30 PM in New
+ York City in each of the three time formats, using the "DTSTART"
+ property.
+
+ DTSTART:19970714T133000 ; Local time
+ DTSTART:19970714T173000Z ; UTC time
+ DTSTART;TZID=America/New_York:19970714T133000
+ ; Local time and time
+ ; zone reference
+
+3.3.6. Duration
+
+ Value Name: DURATION
+
+ Purpose: This value type is used to identify properties that contain
+ a duration of time.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ dur-value = (["+"] / "-") "P" (dur-date / dur-time / dur-week)
+
+ dur-date = dur-day [dur-time]
+ dur-time = "T" (dur-hour / dur-minute / dur-second)
+ dur-week = 1*DIGIT "W"
+ dur-hour = 1*DIGIT "H" [dur-minute]
+ dur-minute = 1*DIGIT "M" [dur-second]
+ dur-second = 1*DIGIT "S"
+ dur-day = 1*DIGIT "D"
+
+ Description: If the property permits, multiple "duration" values are
+ specified by a COMMA-separated list of values. The format is
+ based on the [ISO.8601.2004] complete representation basic format
+ with designators for the duration of time. The format can
+ represent nominal durations (weeks and days) and accurate
+ durations (hours, minutes, and seconds). Note that unlike
+ [ISO.8601.2004], this value type doesn't support the "Y" and "M"
+ designators to specify durations in terms of years and months.
+
+
+
+
+
+Desruisseaux Standards Track [Page 35]
+
+RFC 5545 iCalendar September 2009
+
+
+ The duration of a week or a day depends on its position in the
+ calendar. In the case of discontinuities in the time scale, such
+ as the change from standard time to daylight time and back, the
+ computation of the exact duration requires the subtraction or
+ addition of the change of duration of the discontinuity. Leap
+ seconds MUST NOT be considered when computing an exact duration.
+ When computing an exact duration, the greatest order time
+ components MUST be added first, that is, the number of days MUST
+ be added first, followed by the number of hours, number of
+ minutes, and number of seconds.
+
+ Negative durations are typically used to schedule an alarm to
+ trigger before an associated time (see Section 3.8.6.3).
+
+ No additional content value encoding (i.e., BACKSLASH character
+ encoding, see Section 3.3.11) are defined for this value type.
+
+ Example: A duration of 15 days, 5 hours, and 20 seconds would be:
+
+ P15DT5H0M20S
+
+ A duration of 7 weeks would be:
+
+ P7W
+
+3.3.7. Float
+
+ Value Name: FLOAT
+
+ Purpose: This value type is used to identify properties that contain
+ a real-number value.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ float = (["+"] / "-") 1*DIGIT ["." 1*DIGIT]
+
+ Description: If the property permits, multiple "float" values are
+ specified by a COMMA-separated list of values.
+
+ No additional content value encoding (i.e., BACKSLASH character
+ encoding, see Section 3.3.11) is defined for this value type.
+
+ Example:
+
+ 1000000.0000001
+ 1.333
+ -3.14
+
+
+
+Desruisseaux Standards Track [Page 36]
+
+RFC 5545 iCalendar September 2009
+
+
+3.3.8. Integer
+
+ Value Name: INTEGER
+
+ Purpose: This value type is used to identify properties that contain
+ a signed integer value.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ integer = (["+"] / "-") 1*DIGIT
+
+ Description: If the property permits, multiple "integer" values are
+ specified by a COMMA-separated list of values. The valid range
+ for "integer" is -2147483648 to 2147483647. If the sign is not
+ specified, then the value is assumed to be positive.
+
+ No additional content value encoding (i.e., BACKSLASH character
+ encoding, see Section 3.3.11) is defined for this value type.
+
+ Example:
+
+ 1234567890
+ -1234567890
+ +1234567890
+ 432109876
+
+3.3.9. Period of Time
+
+ Value Name: PERIOD
+
+ Purpose: This value type is used to identify values that contain a
+ precise period of time.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ period = period-explicit / period-start
+
+ period-explicit = date-time "/" date-time
+ ; [ISO.8601.2004] complete representation basic format for a
+ ; period of time consisting of a start and end. The start MUST
+ ; be before the end.
+
+ period-start = date-time "/" dur-value
+ ; [ISO.8601.2004] complete representation basic format for a
+ ; period of time consisting of a start and positive duration
+ ; of time.
+
+
+
+Desruisseaux Standards Track [Page 37]
+
+RFC 5545 iCalendar September 2009
+
+
+ Description: If the property permits, multiple "period" values are
+ specified by a COMMA-separated list of values. There are two
+ forms of a period of time. First, a period of time is identified
+ by its start and its end. This format is based on the
+ [ISO.8601.2004] complete representation, basic format for "DATE-
+ TIME" start of the period, followed by a SOLIDUS character
+ followed by the "DATE-TIME" of the end of the period. The start
+ of the period MUST be before the end of the period. Second, a
+ period of time can also be defined by a start and a positive
+ duration of time. The format is based on the [ISO.8601.2004]
+ complete representation, basic format for the "DATE-TIME" start of
+ the period, followed by a SOLIDUS character, followed by the
+ [ISO.8601.2004] basic format for "DURATION" of the period.
+
+ Example: The period starting at 18:00:00 UTC, on January 1, 1997 and
+ ending at 07:00:00 UTC on January 2, 1997 would be:
+
+ 19970101T180000Z/19970102T070000Z
+
+ The period start at 18:00:00 on January 1, 1997 and lasting 5
+ hours and 30 minutes would be:
+
+ 19970101T180000Z/PT5H30M
+
+ No additional content value encoding (i.e., BACKSLASH character
+ encoding, see Section 3.3.11) is defined for this value type.
+
+3.3.10. Recurrence Rule
+
+ Value Name: RECUR
+
+ Purpose: This value type is used to identify properties that contain
+ a recurrence rule specification.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ recur = recur-rule-part *( ";" recur-rule-part )
+ ;
+ ; The rule parts are not ordered in any
+ ; particular sequence.
+ ;
+ ; The FREQ rule part is REQUIRED,
+ ; but MUST NOT occur more than once.
+ ;
+ ; The UNTIL or COUNT rule parts are OPTIONAL,
+ ; but they MUST NOT occur in the same 'recur'.
+ ;
+
+
+
+Desruisseaux Standards Track [Page 38]
+
+RFC 5545 iCalendar September 2009
+
+
+ ; The other rule parts are OPTIONAL,
+ ; but MUST NOT occur more than once.
+
+ recur-rule-part = ( "FREQ" "=" freq )
+ / ( "UNTIL" "=" enddate )
+ / ( "COUNT" "=" 1*DIGIT )
+ / ( "INTERVAL" "=" 1*DIGIT )
+ / ( "BYSECOND" "=" byseclist )
+ / ( "BYMINUTE" "=" byminlist )
+ / ( "BYHOUR" "=" byhrlist )
+ / ( "BYDAY" "=" bywdaylist )
+ / ( "BYMONTHDAY" "=" bymodaylist )
+ / ( "BYYEARDAY" "=" byyrdaylist )
+ / ( "BYWEEKNO" "=" bywknolist )
+ / ( "BYMONTH" "=" bymolist )
+ / ( "BYSETPOS" "=" bysplist )
+ / ( "WKST" "=" weekday )
+
+ freq = "SECONDLY" / "MINUTELY" / "HOURLY" / "DAILY"
+ / "WEEKLY" / "MONTHLY" / "YEARLY"
+
+ enddate = date / date-time
+
+ byseclist = ( seconds *("," seconds) )
+
+ seconds = 1*2DIGIT ;0 to 60
+
+ byminlist = ( minutes *("," minutes) )
+
+ minutes = 1*2DIGIT ;0 to 59
+
+ byhrlist = ( hour *("," hour) )
+
+ hour = 1*2DIGIT ;0 to 23
+
+ bywdaylist = ( weekdaynum *("," weekdaynum) )
+
+ weekdaynum = [[plus / minus] ordwk] weekday
+
+ plus = "+"
+
+ minus = "-"
+
+ ordwk = 1*2DIGIT ;1 to 53
+
+ weekday = "SU" / "MO" / "TU" / "WE" / "TH" / "FR" / "SA"
+ ;Corresponding to SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY,
+ ;FRIDAY, and SATURDAY days of the week.
+
+
+
+Desruisseaux Standards Track [Page 39]
+
+RFC 5545 iCalendar September 2009
+
+
+ bymodaylist = ( monthdaynum *("," monthdaynum) )
+
+ monthdaynum = [plus / minus] ordmoday
+
+ ordmoday = 1*2DIGIT ;1 to 31
+
+ byyrdaylist = ( yeardaynum *("," yeardaynum) )
+
+ yeardaynum = [plus / minus] ordyrday
+
+ ordyrday = 1*3DIGIT ;1 to 366
+
+ bywknolist = ( weeknum *("," weeknum) )
+
+ weeknum = [plus / minus] ordwk
+
+ bymolist = ( monthnum *("," monthnum) )
+
+ monthnum = 1*2DIGIT ;1 to 12
+
+ bysplist = ( setposday *("," setposday) )
+
+ setposday = yeardaynum
+
+ Description: This value type is a structured value consisting of a
+ list of one or more recurrence grammar parts. Each rule part is
+ defined by a NAME=VALUE pair. The rule parts are separated from
+ each other by the SEMICOLON character. The rule parts are not
+ ordered in any particular sequence. Individual rule parts MUST
+ only be specified once. Compliant applications MUST accept rule
+ parts ordered in any sequence, but to ensure backward
+ compatibility with applications that pre-date this revision of
+ iCalendar the FREQ rule part MUST be the first rule part specified
+ in a RECUR value.
+
+ The FREQ rule part identifies the type of recurrence rule. This
+ rule part MUST be specified in the recurrence rule. Valid values
+ include SECONDLY, to specify repeating events based on an interval
+ of a second or more; MINUTELY, to specify repeating events based
+ on an interval of a minute or more; HOURLY, to specify repeating
+ events based on an interval of an hour or more; DAILY, to specify
+ repeating events based on an interval of a day or more; WEEKLY, to
+ specify repeating events based on an interval of a week or more;
+ MONTHLY, to specify repeating events based on an interval of a
+ month or more; and YEARLY, to specify repeating events based on an
+ interval of a year or more.
+
+
+
+
+
+Desruisseaux Standards Track [Page 40]
+
+RFC 5545 iCalendar September 2009
+
+
+ The INTERVAL rule part contains a positive integer representing at
+ which intervals the recurrence rule repeats. The default value is
+ "1", meaning every second for a SECONDLY rule, every minute for a
+ MINUTELY rule, every hour for an HOURLY rule, every day for a
+ DAILY rule, every week for a WEEKLY rule, every month for a
+ MONTHLY rule, and every year for a YEARLY rule. For example,
+ within a DAILY rule, a value of "8" means every eight days.
+
+ The UNTIL rule part defines a DATE or DATE-TIME value that bounds
+ the recurrence rule in an inclusive manner. If the value
+ specified by UNTIL is synchronized with the specified recurrence,
+ this DATE or DATE-TIME becomes the last instance of the
+ recurrence. The value of the UNTIL rule part MUST have the same
+ value type as the "DTSTART" property. Furthermore, if the
+ "DTSTART" property is specified as a date with local time, then
+ the UNTIL rule part MUST also be specified as a date with local
+ time. If the "DTSTART" property is specified as a date with UTC
+ time or a date with local time and time zone reference, then the
+ UNTIL rule part MUST be specified as a date with UTC time. In the
+ case of the "STANDARD" and "DAYLIGHT" sub-components the UNTIL
+ rule part MUST always be specified as a date with UTC time. If
+ specified as a DATE-TIME value, then it MUST be specified in a UTC
+ time format. If not present, and the COUNT rule part is also not
+ present, the "RRULE" is considered to repeat forever.
+
+ The COUNT rule part defines the number of occurrences at which to
+ range-bound the recurrence. The "DTSTART" property value always
+ counts as the first occurrence.
+
+ The BYSECOND rule part specifies a COMMA-separated list of seconds
+ within a minute. Valid values are 0 to 60. The BYMINUTE rule
+ part specifies a COMMA-separated list of minutes within an hour.
+ Valid values are 0 to 59. The BYHOUR rule part specifies a COMMA-
+ separated list of hours of the day. Valid values are 0 to 23.
+ The BYSECOND, BYMINUTE and BYHOUR rule parts MUST NOT be specified
+ when the associated "DTSTART" property has a DATE value type.
+ These rule parts MUST be ignored in RECUR value that violate the
+ above requirement (e.g., generated by applications that pre-date
+ this revision of iCalendar).
+
+ The BYDAY rule part specifies a COMMA-separated list of days of
+ the week; SU indicates Sunday; MO indicates Monday; TU indicates
+ Tuesday; WE indicates Wednesday; TH indicates Thursday; FR
+ indicates Friday; and SA indicates Saturday.
+
+ Each BYDAY value can also be preceded by a positive (+n) or
+ negative (-n) integer. If present, this indicates the nth
+ occurrence of a specific day within the MONTHLY or YEARLY "RRULE".
+
+
+
+Desruisseaux Standards Track [Page 41]
+
+RFC 5545 iCalendar September 2009
+
+
+ For example, within a MONTHLY rule, +1MO (or simply 1MO)
+ represents the first Monday within the month, whereas -1MO
+ represents the last Monday of the month. The numeric value in a
+ BYDAY rule part with the FREQ rule part set to YEARLY corresponds
+ to an offset within the month when the BYMONTH rule part is
+ present, and corresponds to an offset within the year when the
+ BYWEEKNO or BYMONTH rule parts are present. If an integer
+ modifier is not present, it means all days of this type within the
+ specified frequency. For example, within a MONTHLY rule, MO
+ represents all Mondays within the month. The BYDAY rule part MUST
+ NOT be specified with a numeric value when the FREQ rule part is
+ not set to MONTHLY or YEARLY. Furthermore, the BYDAY rule part
+ MUST NOT be specified with a numeric value with the FREQ rule part
+ set to YEARLY when the BYWEEKNO rule part is specified.
+
+ The BYMONTHDAY rule part specifies a COMMA-separated list of days
+ of the month. Valid values are 1 to 31 or -31 to -1. For
+ example, -10 represents the tenth to the last day of the month.
+ The BYMONTHDAY rule part MUST NOT be specified when the FREQ rule
+ part is set to WEEKLY.
+
+ The BYYEARDAY rule part specifies a COMMA-separated list of days
+ of the year. Valid values are 1 to 366 or -366 to -1. For
+ example, -1 represents the last day of the year (December 31st)
+ and -306 represents the 306th to the last day of the year (March
+ 1st). The BYYEARDAY rule part MUST NOT be specified when the FREQ
+ rule part is set to DAILY, WEEKLY, or MONTHLY.
+
+ The BYWEEKNO rule part specifies a COMMA-separated list of
+ ordinals specifying weeks of the year. Valid values are 1 to 53
+ or -53 to -1. This corresponds to weeks according to week
+ numbering as defined in [ISO.8601.2004]. A week is defined as a
+ seven day period, starting on the day of the week defined to be
+ the week start (see WKST). Week number one of the calendar year
+ is the first week that contains at least four (4) days in that
+ calendar year. This rule part MUST NOT be used when the FREQ rule
+ part is set to anything other than YEARLY. For example, 3
+ represents the third week of the year.
+
+ Note: Assuming a Monday week start, week 53 can only occur when
+ Thursday is January 1 or if it is a leap year and Wednesday is
+ January 1.
+
+ The BYMONTH rule part specifies a COMMA-separated list of months
+ of the year. Valid values are 1 to 12.
+
+ The WKST rule part specifies the day on which the workweek starts.
+ Valid values are MO, TU, WE, TH, FR, SA, and SU. This is
+
+
+
+Desruisseaux Standards Track [Page 42]
+
+RFC 5545 iCalendar September 2009
+
+
+ significant when a WEEKLY "RRULE" has an interval greater than 1,
+ and a BYDAY rule part is specified. This is also significant when
+ in a YEARLY "RRULE" when a BYWEEKNO rule part is specified. The
+ default value is MO.
+
+ The BYSETPOS rule part specifies a COMMA-separated list of values
+ that corresponds to the nth occurrence within the set of
+ recurrence instances specified by the rule. BYSETPOS operates on
+ a set of recurrence instances in one interval of the recurrence
+ rule. For example, in a WEEKLY rule, the interval would be one
+ week A set of recurrence instances starts at the beginning of the
+ interval defined by the FREQ rule part. Valid values are 1 to 366
+ or -366 to -1. It MUST only be used in conjunction with another
+ BYxxx rule part. For example "the last work day of the month"
+ could be represented as:
+
+ FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-1
+
+ Each BYSETPOS value can include a positive (+n) or negative (-n)
+ integer. If present, this indicates the nth occurrence of the
+ specific occurrence within the set of occurrences specified by the
+ rule.
+
+ Recurrence rules may generate recurrence instances with an invalid
+ date (e.g., February 30) or nonexistent local time (e.g., 1:30 AM
+ on a day where the local time is moved forward by an hour at 1:00
+ AM). Such recurrence instances MUST be ignored and MUST NOT be
+ counted as part of the recurrence set.
+
+ Information, not contained in the rule, necessary to determine the
+ various recurrence instance start time and dates are derived from
+ the Start Time ("DTSTART") component attribute. For example,
+ "FREQ=YEARLY;BYMONTH=1" doesn't specify a specific day within the
+ month or a time. This information would be the same as what is
+ specified for "DTSTART".
+
+ BYxxx rule parts modify the recurrence in some manner. BYxxx rule
+ parts for a period of time that is the same or greater than the
+ frequency generally reduce or limit the number of occurrences of
+ the recurrence generated. For example, "FREQ=DAILY;BYMONTH=1"
+ reduces the number of recurrence instances from all days (if
+ BYMONTH rule part is not present) to all days in January. BYxxx
+ rule parts for a period of time less than the frequency generally
+ increase or expand the number of occurrences of the recurrence.
+ For example, "FREQ=YEARLY;BYMONTH=1,2" increases the number of
+ days within the yearly recurrence set from 1 (if BYMONTH rule part
+ is not present) to 2.
+
+
+
+
+Desruisseaux Standards Track [Page 43]
+
+RFC 5545 iCalendar September 2009
+
+
+ If multiple BYxxx rule parts are specified, then after evaluating
+ the specified FREQ and INTERVAL rule parts, the BYxxx rule parts
+ are applied to the current set of evaluated occurrences in the
+ following order: BYMONTH, BYWEEKNO, BYYEARDAY, BYMONTHDAY, BYDAY,
+ BYHOUR, BYMINUTE, BYSECOND and BYSETPOS; then COUNT and UNTIL are
+ evaluated.
+
+ The table below summarizes the dependency of BYxxx rule part
+ expand or limit behavior on the FREQ rule part value.
+
+ The term "N/A" means that the corresponding BYxxx rule part MUST
+ NOT be used with the corresponding FREQ value.
+
+ BYDAY has some special behavior depending on the FREQ value and
+ this is described in separate notes below the table.
+
+ +----------+--------+--------+-------+-------+------+-------+------+
+ | |SECONDLY|MINUTELY|HOURLY |DAILY |WEEKLY|MONTHLY|YEARLY|
+ +----------+--------+--------+-------+-------+------+-------+------+
+ |BYMONTH |Limit |Limit |Limit |Limit |Limit |Limit |Expand|
+ +----------+--------+--------+-------+-------+------+-------+------+
+ |BYWEEKNO |N/A |N/A |N/A |N/A |N/A |N/A |Expand|
+ +----------+--------+--------+-------+-------+------+-------+------+
+ |BYYEARDAY |Limit |Limit |Limit |N/A |N/A |N/A |Expand|
+ +----------+--------+--------+-------+-------+------+-------+------+
+ |BYMONTHDAY|Limit |Limit |Limit |Limit |N/A |Expand |Expand|
+ +----------+--------+--------+-------+-------+------+-------+------+
+ |BYDAY |Limit |Limit |Limit |Limit |Expand|Note 1 |Note 2|
+ +----------+--------+--------+-------+-------+------+-------+------+
+ |BYHOUR |Limit |Limit |Limit |Expand |Expand|Expand |Expand|
+ +----------+--------+--------+-------+-------+------+-------+------+
+ |BYMINUTE |Limit |Limit |Expand |Expand |Expand|Expand |Expand|
+ +----------+--------+--------+-------+-------+------+-------+------+
+ |BYSECOND |Limit |Expand |Expand |Expand |Expand|Expand |Expand|
+ +----------+--------+--------+-------+-------+------+-------+------+
+ |BYSETPOS |Limit |Limit |Limit |Limit |Limit |Limit |Limit |
+ +----------+--------+--------+-------+-------+------+-------+------+
+
+ Note 1: Limit if BYMONTHDAY is present; otherwise, special expand
+ for MONTHLY.
+
+ Note 2: Limit if BYYEARDAY or BYMONTHDAY is present; otherwise,
+ special expand for WEEKLY if BYWEEKNO present; otherwise,
+ special expand for MONTHLY if BYMONTH present; otherwise,
+ special expand for YEARLY.
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 44]
+
+RFC 5545 iCalendar September 2009
+
+
+ Here is an example of evaluating multiple BYxxx rule parts.
+
+ DTSTART;TZID=America/New_York:19970105T083000
+ RRULE:FREQ=YEARLY;INTERVAL=2;BYMONTH=1;BYDAY=SU;BYHOUR=8,9;
+ BYMINUTE=30
+
+ First, the "INTERVAL=2" would be applied to "FREQ=YEARLY" to
+ arrive at "every other year". Then, "BYMONTH=1" would be applied
+ to arrive at "every January, every other year". Then, "BYDAY=SU"
+ would be applied to arrive at "every Sunday in January, every
+ other year". Then, "BYHOUR=8,9" would be applied to arrive at
+ "every Sunday in January at 8 AM and 9 AM, every other year".
+ Then, "BYMINUTE=30" would be applied to arrive at "every Sunday in
+ January at 8:30 AM and 9:30 AM, every other year". Then, lacking
+ information from "RRULE", the second is derived from "DTSTART", to
+ end up in "every Sunday in January at 8:30:00 AM and 9:30:00 AM,
+ every other year". Similarly, if the BYMINUTE, BYHOUR, BYDAY,
+ BYMONTHDAY, or BYMONTH rule part were missing, the appropriate
+ minute, hour, day, or month would have been retrieved from the
+ "DTSTART" property.
+
+ If the computed local start time of a recurrence instance does not
+ exist, or occurs more than once, for the specified time zone, the
+ time of the recurrence instance is interpreted in the same manner
+ as an explicit DATE-TIME value describing that date and time, as
+ specified in Section 3.3.5.
+
+ No additional content value encoding (i.e., BACKSLASH character
+ encoding, see Section 3.3.11) is defined for this value type.
+
+ Example: The following is a rule that specifies 10 occurrences that
+ occur every other day:
+
+ FREQ=DAILY;COUNT=10;INTERVAL=2
+
+ There are other examples specified in Section 3.8.5.3.
+
+3.3.11. Text
+
+ Value Name: TEXT
+
+ Purpose: This value type is used to identify values that contain
+ human-readable text.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+
+
+
+
+Desruisseaux Standards Track [Page 45]
+
+RFC 5545 iCalendar September 2009
+
+
+ text = *(TSAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR)
+ ; Folded according to description above
+
+ ESCAPED-CHAR = ("\\" / "\;" / "\," / "\N" / "\n")
+ ; \\ encodes \, \N or \n encodes newline
+ ; \; encodes ;, \, encodes ,
+
+ TSAFE-CHAR = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-5B /
+ %x5D-7E / NON-US-ASCII
+ ; Any character except CONTROLs not needed by the current
+ ; character set, DQUOTE, ";", ":", "\", ","
+
+ Description: If the property permits, multiple TEXT values are
+ specified by a COMMA-separated list of values.
+
+ The language in which the text is represented can be controlled by
+ the "LANGUAGE" property parameter.
+
+ An intentional formatted text line break MUST only be included in
+ a "TEXT" property value by representing the line break with the
+ character sequence of BACKSLASH, followed by a LATIN SMALL LETTER
+ N or a LATIN CAPITAL LETTER N, that is "\n" or "\N".
+
+ The "TEXT" property values may also contain special characters
+ that are used to signify delimiters, such as a COMMA character for
+ lists of values or a SEMICOLON character for structured values.
+ In order to support the inclusion of these special characters in
+ "TEXT" property values, they MUST be escaped with a BACKSLASH
+ character. A BACKSLASH character in a "TEXT" property value MUST
+ be escaped with another BACKSLASH character. A COMMA character in
+ a "TEXT" property value MUST be escaped with a BACKSLASH
+ character. A SEMICOLON character in a "TEXT" property value MUST
+ be escaped with a BACKSLASH character. However, a COLON character
+ in a "TEXT" property value SHALL NOT be escaped with a BACKSLASH
+ character.
+
+ Example: A multiple line value of:
+
+ Project XYZ Final Review
+ Conference Room - 3B
+ Come Prepared.
+
+ would be represented as:
+
+ Project XYZ Final Review\nConference Room - 3B\nCome Prepared.
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 46]
+
+RFC 5545 iCalendar September 2009
+
+
+3.3.12. Time
+
+ Value Name: TIME
+
+ Purpose: This value type is used to identify values that contain a
+ time of day.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ time = time-hour time-minute time-second [time-utc]
+
+ time-hour = 2DIGIT ;00-23
+ time-minute = 2DIGIT ;00-59
+ time-second = 2DIGIT ;00-60
+ ;The "60" value is used to account for positive "leap" seconds.
+
+ time-utc = "Z"
+
+ Description: If the property permits, multiple "time" values are
+ specified by a COMMA-separated list of values. No additional
+ content value encoding (i.e., BACKSLASH character encoding, see
+ Section 3.3.11) is defined for this value type.
+
+ The "TIME" value type is used to identify values that contain a
+ time of day. The format is based on the [ISO.8601.2004] complete
+ representation, basic format for a time of day. The text format
+ consists of a two-digit, 24-hour of the day (i.e., values 00-23),
+ two-digit minute in the hour (i.e., values 00-59), and two-digit
+ seconds in the minute (i.e., values 00-60). The seconds value of
+ 60 MUST only be used to account for positive "leap" seconds.
+ Fractions of a second are not supported by this format.
+
+ In parallel to the "DATE-TIME" definition above, the "TIME" value
+ type expresses time values in three forms:
+
+ The form of time with UTC offset MUST NOT be used. For example,
+ the following is not valid for a time value:
+
+ 230000-0800 ;Invalid time format
+
+ FORM #1 LOCAL TIME
+
+ The local time form is simply a time value that does not contain
+ the UTC designator nor does it reference a time zone. For
+ example, 11:00 PM:
+
+ 230000
+
+
+
+Desruisseaux Standards Track [Page 47]
+
+RFC 5545 iCalendar September 2009
+
+
+ Time values of this type are said to be "floating" and are not
+ bound to any time zone in particular. They are used to represent
+ the same hour, minute, and second value regardless of which time
+ zone is currently being observed. For example, an event can be
+ defined that indicates that an individual will be busy from 11:00
+ AM to 1:00 PM every day, no matter which time zone the person is
+ in. In these cases, a local time can be specified. The recipient
+ of an iCalendar object with a property value consisting of a local
+ time, without any relative time zone information, SHOULD interpret
+ the value as being fixed to whatever time zone the "ATTENDEE" is
+ in at any given moment. This means that two "Attendees", may
+ participate in the same event at different UTC times; floating
+ time SHOULD only be used where that is reasonable behavior.
+
+ In most cases, a fixed time is desired. To properly communicate a
+ fixed time in a property value, either UTC time or local time with
+ time zone reference MUST be specified.
+
+ The use of local time in a TIME value without the "TZID" property
+ parameter is to be interpreted as floating time, regardless of the
+ existence of "VTIMEZONE" calendar components in the iCalendar
+ object.
+
+ FORM #2: UTC TIME
+
+ UTC time, or absolute time, is identified by a LATIN CAPITAL
+ LETTER Z suffix character, the UTC designator, appended to the
+ time value. For example, the following represents 07:00 AM UTC:
+
+ 070000Z
+
+ The "TZID" property parameter MUST NOT be applied to TIME
+ properties whose time values are specified in UTC.
+
+ FORM #3: LOCAL TIME AND TIME ZONE REFERENCE
+
+ The local time with reference to time zone information form is
+ identified by the use the "TZID" property parameter to reference
+ the appropriate time zone definition. "TZID" is discussed in
+ detail in Section 3.2.19.
+
+ Example: The following represents 8:30 AM in New York in winter,
+ five hours behind UTC, in each of the three formats:
+
+ 083000
+ 133000Z
+ TZID=America/New_York:083000
+
+
+
+
+Desruisseaux Standards Track [Page 48]
+
+RFC 5545 iCalendar September 2009
+
+
+3.3.13. URI
+
+ Value Name: URI
+
+ Purpose: This value type is used to identify values that contain a
+ uniform resource identifier (URI) type of reference to the
+ property value.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ uri = <As defined in Section 3 of [RFC3986]>
+
+ Description: This value type might be used to reference binary
+ information, for values that are large, or otherwise undesirable
+ to include directly in the iCalendar object.
+
+ Property values with this value type MUST follow the generic URI
+ syntax defined in [RFC3986].
+
+ When a property parameter value is a URI value type, the URI MUST
+ be specified as a quoted-string value.
+
+ No additional content value encoding (i.e., BACKSLASH character
+ encoding, see Section 3.3.11) is defined for this value type.
+
+ Example: The following is a URI for a network file:
+
+ http://example.com/my-report.txt
+
+3.3.14. UTC Offset
+
+ Value Name: UTC-OFFSET
+
+ Purpose: This value type is used to identify properties that contain
+ an offset from UTC to local time.
+
+ Format Definition: This value type is defined by the following
+ notation:
+
+ utc-offset = time-numzone
+
+ time-numzone = ("+" / "-") time-hour time-minute [time-second]
+
+ Description: The PLUS SIGN character MUST be specified for positive
+ UTC offsets (i.e., ahead of UTC). The HYPHEN-MINUS character MUST
+ be specified for negative UTC offsets (i.e., behind of UTC). The
+
+
+
+
+Desruisseaux Standards Track [Page 49]
+
+RFC 5545 iCalendar September 2009
+
+
+ value of "-0000" and "-000000" are not allowed. The time-second,
+ if present, MUST NOT be 60; if absent, it defaults to zero.
+
+ No additional content value encoding (i.e., BACKSLASH character
+ encoding, see Section 3.3.11) is defined for this value type.
+
+ Example: The following UTC offsets are given for standard time for
+ New York (five hours behind UTC) and Geneva (one hour ahead of
+ UTC):
+
+ -0500
+
+ +0100
+
+3.4. iCalendar Object
+
+ The Calendaring and Scheduling Core Object is a collection of
+ calendaring and scheduling information. Typically, this information
+ will consist of an iCalendar stream with a single iCalendar object.
+ However, multiple iCalendar objects can be sequentially grouped
+ together in an iCalendar stream. The first line and last line of the
+ iCalendar object MUST contain a pair of iCalendar object delimiter
+ strings. The syntax for an iCalendar stream is as follows:
+
+ icalstream = 1*icalobject
+
+ icalobject = "BEGIN" ":" "VCALENDAR" CRLF
+ icalbody
+ "END" ":" "VCALENDAR" CRLF
+
+ The following is a simple example of an iCalendar object:
+
+ BEGIN:VCALENDAR
+ VERSION:2.0
+ PRODID:-//hacksw/handcal//NONSGML v1.0//EN
+ BEGIN:VEVENT
+ UID:19970610T172345Z-AF23B2@example.com
+ DTSTAMP:19970610T172345Z
+ DTSTART:19970714T170000Z
+ DTEND:19970715T040000Z
+ SUMMARY:Bastille Day Party
+ END:VEVENT
+ END:VCALENDAR
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 50]
+
+RFC 5545 iCalendar September 2009
+
+
+3.5. Property
+
+ A property is the definition of an individual attribute describing a
+ calendar object or a calendar component. A property takes the form
+ defined by the "contentline" notation defined in Section 3.1.
+
+ The following is an example of a property:
+
+ DTSTART:19960415T133000Z
+
+ This memo imposes no ordering of properties within an iCalendar
+ object.
+
+ Property names, parameter names, and enumerated parameter values are
+ case-insensitive. For example, the property name "DUE" is the same
+ as "due" and "Due", DTSTART;TZID=America/New_York:19980714T120000 is
+ the same as DtStart;TzID=America/New_York:19980714T120000.
+
+3.6. Calendar Components
+
+ The body of the iCalendar object consists of a sequence of calendar
+ properties and one or more calendar components. The calendar
+ properties are attributes that apply to the calendar object as a
+ whole. The calendar components are collections of properties that
+ express a particular calendar semantic. For example, the calendar
+ component can specify an event, a to-do, a journal entry, time zone
+ information, free/busy time information, or an alarm.
+
+ The body of the iCalendar object is defined by the following
+ notation:
+
+ icalbody = calprops component
+
+ calprops = *(
+ ;
+ ; The following are REQUIRED,
+ ; but MUST NOT occur more than once.
+ ;
+ prodid / version /
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ calscale / method /
+ ;
+ ; The following are OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+
+
+
+Desruisseaux Standards Track [Page 51]
+
+RFC 5545 iCalendar September 2009
+
+
+ x-prop / iana-prop
+ ;
+ )
+
+ component = 1*(eventc / todoc / journalc / freebusyc /
+ timezonec / iana-comp / x-comp)
+
+ iana-comp = "BEGIN" ":" iana-token CRLF
+ 1*contentline
+ "END" ":" iana-token CRLF
+
+ x-comp = "BEGIN" ":" x-name CRLF
+ 1*contentline
+ "END" ":" x-name CRLF
+
+ An iCalendar object MUST include the "PRODID" and "VERSION" calendar
+ properties. In addition, it MUST include at least one calendar
+ component. Special forms of iCalendar objects are possible to
+ publish just busy time (i.e., only a "VFREEBUSY" calendar component)
+ or time zone (i.e., only a "VTIMEZONE" calendar component)
+ information. In addition, a complex iCalendar object that is used to
+ capture a complete snapshot of the contents of a calendar is possible
+ (e.g., composite of many different calendar components). More
+ commonly, an iCalendar object will consist of just a single "VEVENT",
+ "VTODO", or "VJOURNAL" calendar component. Applications MUST ignore
+ x-comp and iana-comp values they don't recognize. Applications that
+ support importing iCalendar objects SHOULD support all of the
+ component types defined in this document, and SHOULD NOT silently
+ drop any components as that can lead to user data loss.
+
+3.6.1. Event Component
+
+ Component Name: VEVENT
+
+ Purpose: Provide a grouping of component properties that describe an
+ event.
+
+ Format Definition: A "VEVENT" calendar component is defined by the
+ following notation:
+
+ eventc = "BEGIN" ":" "VEVENT" CRLF
+ eventprop *alarmc
+ "END" ":" "VEVENT" CRLF
+
+ eventprop = *(
+ ;
+ ; The following are REQUIRED,
+ ; but MUST NOT occur more than once.
+
+
+
+Desruisseaux Standards Track [Page 52]
+
+RFC 5545 iCalendar September 2009
+
+
+ ;
+ dtstamp / uid /
+ ;
+ ; The following is REQUIRED if the component
+ ; appears in an iCalendar object that doesn't
+ ; specify the "METHOD" property; otherwise, it
+ ; is OPTIONAL; in any case, it MUST NOT occur
+ ; more than once.
+ ;
+ dtstart /
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ class / created / description / geo /
+ last-mod / location / organizer / priority /
+ seq / status / summary / transp /
+ url / recurid /
+ ;
+ ; The following is OPTIONAL,
+ ; but SHOULD NOT occur more than once.
+ ;
+ rrule /
+ ;
+ ; Either 'dtend' or 'duration' MAY appear in
+ ; a 'eventprop', but 'dtend' and 'duration'
+ ; MUST NOT occur in the same 'eventprop'.
+ ;
+ dtend / duration /
+ ;
+ ; The following are OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ attach / attendee / categories / comment /
+ contact / exdate / rstatus / related /
+ resources / rdate / x-prop / iana-prop
+ ;
+ )
+
+ Description: A "VEVENT" calendar component is a grouping of
+ component properties, possibly including "VALARM" calendar
+ components, that represents a scheduled amount of time on a
+ calendar. For example, it can be an activity; such as a one-hour
+ long, department meeting from 8:00 AM to 9:00 AM, tomorrow.
+ Generally, an event will take up time on an individual calendar.
+ Hence, the event will appear as an opaque interval in a search for
+ busy time. Alternately, the event can have its Time Transparency
+
+
+
+
+Desruisseaux Standards Track [Page 53]
+
+RFC 5545 iCalendar September 2009
+
+
+ set to "TRANSPARENT" in order to prevent blocking of the event in
+ searches for busy time.
+
+ The "VEVENT" is also the calendar component used to specify an
+ anniversary or daily reminder within a calendar. These events
+ have a DATE value type for the "DTSTART" property instead of the
+ default value type of DATE-TIME. If such a "VEVENT" has a "DTEND"
+ property, it MUST be specified as a DATE value also. The
+ anniversary type of "VEVENT" can span more than one date (i.e.,
+ "DTEND" property value is set to a calendar date after the
+ "DTSTART" property value). If such a "VEVENT" has a "DURATION"
+ property, it MUST be specified as a "dur-day" or "dur-week" value.
+
+ The "DTSTART" property for a "VEVENT" specifies the inclusive
+ start of the event. For recurring events, it also specifies the
+ very first instance in the recurrence set. The "DTEND" property
+ for a "VEVENT" calendar component specifies the non-inclusive end
+ of the event. For cases where a "VEVENT" calendar component
+ specifies a "DTSTART" property with a DATE value type but no
+ "DTEND" nor "DURATION" property, the event's duration is taken to
+ be one day. For cases where a "VEVENT" calendar component
+ specifies a "DTSTART" property with a DATE-TIME value type but no
+ "DTEND" property, the event ends on the same calendar date and
+ time of day specified by the "DTSTART" property.
+
+ The "VEVENT" calendar component cannot be nested within another
+ calendar component. However, "VEVENT" calendar components can be
+ related to each other or to a "VTODO" or to a "VJOURNAL" calendar
+ component with the "RELATED-TO" property.
+
+ Example: The following is an example of the "VEVENT" calendar
+ component used to represent a meeting that will also be opaque to
+ searches for busy time:
+
+ BEGIN:VEVENT
+ UID:19970901T130000Z-123401@example.com
+ DTSTAMP:19970901T130000Z
+ DTSTART:19970903T163000Z
+ DTEND:19970903T190000Z
+ SUMMARY:Annual Employee Review
+ CLASS:PRIVATE
+ CATEGORIES:BUSINESS,HUMAN RESOURCES
+ END:VEVENT
+
+ The following is an example of the "VEVENT" calendar component
+ used to represent a reminder that will not be opaque, but rather
+ transparent, to searches for busy time:
+
+
+
+
+Desruisseaux Standards Track [Page 54]
+
+RFC 5545 iCalendar September 2009
+
+
+ BEGIN:VEVENT
+ UID:19970901T130000Z-123402@example.com
+ DTSTAMP:19970901T130000Z
+ DTSTART:19970401T163000Z
+ DTEND:19970402T010000Z
+ SUMMARY:Laurel is in sensitivity awareness class.
+ CLASS:PUBLIC
+ CATEGORIES:BUSINESS,HUMAN RESOURCES
+ TRANSP:TRANSPARENT
+ END:VEVENT
+
+ The following is an example of the "VEVENT" calendar component
+ used to represent an anniversary that will occur annually:
+
+ BEGIN:VEVENT
+ UID:19970901T130000Z-123403@example.com
+ DTSTAMP:19970901T130000Z
+ DTSTART;VALUE=DATE:19971102
+ SUMMARY:Our Blissful Anniversary
+ TRANSP:TRANSPARENT
+ CLASS:CONFIDENTIAL
+ CATEGORIES:ANNIVERSARY,PERSONAL,SPECIAL OCCASION
+ RRULE:FREQ=YEARLY
+ END:VEVENT
+
+ The following is an example of the "VEVENT" calendar component
+ used to represent a multi-day event scheduled from June 28th, 2007
+ to July 8th, 2007 inclusively. Note that the "DTEND" property is
+ set to July 9th, 2007, since the "DTEND" property specifies the
+ non-inclusive end of the event.
+
+ BEGIN:VEVENT
+ UID:20070423T123432Z-541111@example.com
+ DTSTAMP:20070423T123432Z
+ DTSTART;VALUE=DATE:20070628
+ DTEND;VALUE=DATE:20070709
+ SUMMARY:Festival International de Jazz de Montreal
+ TRANSP:TRANSPARENT
+ END:VEVENT
+
+3.6.2. To-Do Component
+
+ Component Name: VTODO
+
+ Purpose: Provide a grouping of calendar properties that describe a
+ to-do.
+
+
+
+
+
+Desruisseaux Standards Track [Page 55]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: A "VTODO" calendar component is defined by the
+ following notation:
+
+ todoc = "BEGIN" ":" "VTODO" CRLF
+ todoprop *alarmc
+ "END" ":" "VTODO" CRLF
+
+ todoprop = *(
+ ;
+ ; The following are REQUIRED,
+ ; but MUST NOT occur more than once.
+ ;
+ dtstamp / uid /
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ class / completed / created / description /
+ dtstart / geo / last-mod / location / organizer /
+ percent / priority / recurid / seq / status /
+ summary / url /
+ ;
+ ; The following is OPTIONAL,
+ ; but SHOULD NOT occur more than once.
+ ;
+ rrule /
+ ;
+ ; Either 'due' or 'duration' MAY appear in
+ ; a 'todoprop', but 'due' and 'duration'
+ ; MUST NOT occur in the same 'todoprop'.
+ ; If 'duration' appear in a 'todoprop',
+ ; then 'dtstart' MUST also appear in
+ ; the same 'todoprop'.
+ ;
+ due / duration /
+ ;
+ ; The following are OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ attach / attendee / categories / comment / contact /
+ exdate / rstatus / related / resources /
+ rdate / x-prop / iana-prop
+ ;
+ )
+
+ Description: A "VTODO" calendar component is a grouping of component
+ properties and possibly "VALARM" calendar components that
+ represent an action-item or assignment. For example, it can be
+
+
+
+Desruisseaux Standards Track [Page 56]
+
+RFC 5545 iCalendar September 2009
+
+
+ used to represent an item of work assigned to an individual; such
+ as "turn in travel expense today".
+
+ The "VTODO" calendar component cannot be nested within another
+ calendar component. However, "VTODO" calendar components can be
+ related to each other or to a "VEVENT" or to a "VJOURNAL" calendar
+ component with the "RELATED-TO" property.
+
+ A "VTODO" calendar component without the "DTSTART" and "DUE" (or
+ "DURATION") properties specifies a to-do that will be associated
+ with each successive calendar date, until it is completed.
+
+ Examples: The following is an example of a "VTODO" calendar
+ component that needs to be completed before May 1st, 2007. On
+ midnight May 1st, 2007 this to-do would be considered overdue.
+
+ BEGIN:VTODO
+ UID:20070313T123432Z-456553@example.com
+ DTSTAMP:20070313T123432Z
+ DUE;VALUE=DATE:20070501
+ SUMMARY:Submit Quebec Income Tax Return for 2006
+ CLASS:CONFIDENTIAL
+ CATEGORIES:FAMILY,FINANCE
+ STATUS:NEEDS-ACTION
+ END:VTODO
+
+ The following is an example of a "VTODO" calendar component that
+ was due before 1:00 P.M. UTC on July 9th, 2007 and was completed
+ on July 7th, 2007 at 10:00 A.M. UTC.
+
+ BEGIN:VTODO
+ UID:20070514T103211Z-123404@example.com
+ DTSTAMP:20070514T103211Z
+ DTSTART:20070514T110000Z
+ DUE:20070709T130000Z
+ COMPLETED:20070707T100000Z
+ SUMMARY:Submit Revised Internet-Draft
+ PRIORITY:1
+ STATUS:NEEDS-ACTION
+ END:VTODO
+
+3.6.3. Journal Component
+
+ Component Name: VJOURNAL
+
+ Purpose: Provide a grouping of component properties that describe a
+ journal entry.
+
+
+
+
+Desruisseaux Standards Track [Page 57]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: A "VJOURNAL" calendar component is defined by the
+ following notation:
+
+ journalc = "BEGIN" ":" "VJOURNAL" CRLF
+ jourprop
+ "END" ":" "VJOURNAL" CRLF
+
+ jourprop = *(
+ ;
+ ; The following are REQUIRED,
+ ; but MUST NOT occur more than once.
+ ;
+ dtstamp / uid /
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ class / created / dtstart /
+ last-mod / organizer / recurid / seq /
+ status / summary / url /
+ ;
+ ; The following is OPTIONAL,
+ ; but SHOULD NOT occur more than once.
+ ;
+ rrule /
+ ;
+ ; The following are OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ attach / attendee / categories / comment /
+ contact / description / exdate / related / rdate /
+ rstatus / x-prop / iana-prop
+ ;
+ )
+
+ Description: A "VJOURNAL" calendar component is a grouping of
+ component properties that represent one or more descriptive text
+ notes associated with a particular calendar date. The "DTSTART"
+ property is used to specify the calendar date with which the
+ journal entry is associated. Generally, it will have a DATE value
+ data type, but it can also be used to specify a DATE-TIME value
+ data type. Examples of a journal entry include a daily record of
+ a legislative body or a journal entry of individual telephone
+ contacts for the day or an ordered list of accomplishments for the
+ day. The "VJOURNAL" calendar component can also be used to
+ associate a document with a calendar date.
+
+
+
+
+
+Desruisseaux Standards Track [Page 58]
+
+RFC 5545 iCalendar September 2009
+
+
+ The "VJOURNAL" calendar component does not take up time on a
+ calendar. Hence, it does not play a role in free or busy time
+ searches -- it is as though it has a time transparency value of
+ TRANSPARENT. It is transparent to any such searches.
+
+ The "VJOURNAL" calendar component cannot be nested within another
+ calendar component. However, "VJOURNAL" calendar components can
+ be related to each other or to a "VEVENT" or to a "VTODO" calendar
+ component, with the "RELATED-TO" property.
+
+ Example: The following is an example of the "VJOURNAL" calendar
+ component:
+
+ BEGIN:VJOURNAL
+ UID:19970901T130000Z-123405@example.com
+ DTSTAMP:19970901T130000Z
+ DTSTART;VALUE=DATE:19970317
+ SUMMARY:Staff meeting minutes
+ DESCRIPTION:1. Staff meeting: Participants include Joe\,
+ Lisa\, and Bob. Aurora project plans were reviewed.
+ There is currently no budget reserves for this project.
+ Lisa will escalate to management. Next meeting on Tuesday.\n
+ 2. Telephone Conference: ABC Corp. sales representative
+ called to discuss new printer. Promised to get us a demo by
+ Friday.\n3. Henry Miller (Handsoff Insurance): Car was
+ totaled by tree. Is looking into a loaner car. 555-2323
+ (tel).
+ END:VJOURNAL
+
+3.6.4. Free/Busy Component
+
+ Component Name: VFREEBUSY
+
+ Purpose: Provide a grouping of component properties that describe
+ either a request for free/busy time, describe a response to a
+ request for free/busy time, or describe a published set of busy
+ time.
+
+ Format Definition: A "VFREEBUSY" calendar component is defined by
+ the following notation:
+
+ freebusyc = "BEGIN" ":" "VFREEBUSY" CRLF
+ fbprop
+ "END" ":" "VFREEBUSY" CRLF
+
+ fbprop = *(
+ ;
+ ; The following are REQUIRED,
+
+
+
+Desruisseaux Standards Track [Page 59]
+
+RFC 5545 iCalendar September 2009
+
+
+ ; but MUST NOT occur more than once.
+ ;
+ dtstamp / uid /
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ contact / dtstart / dtend /
+ organizer / url /
+ ;
+ ; The following are OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ attendee / comment / freebusy / rstatus / x-prop /
+ iana-prop
+ ;
+ )
+
+ Description: A "VFREEBUSY" calendar component is a grouping of
+ component properties that represents either a request for free or
+ busy time information, a reply to a request for free or busy time
+ information, or a published set of busy time information.
+
+ When used to request free/busy time information, the "ATTENDEE"
+ property specifies the calendar users whose free/busy time is
+ being requested; the "ORGANIZER" property specifies the calendar
+ user who is requesting the free/busy time; the "DTSTART" and
+ "DTEND" properties specify the window of time for which the free/
+ busy time is being requested; the "UID" and "DTSTAMP" properties
+ are specified to assist in proper sequencing of multiple free/busy
+ time requests.
+
+ When used to reply to a request for free/busy time, the "ATTENDEE"
+ property specifies the calendar user responding to the free/busy
+ time request; the "ORGANIZER" property specifies the calendar user
+ that originally requested the free/busy time; the "FREEBUSY"
+ property specifies the free/busy time information (if it exists);
+ and the "UID" and "DTSTAMP" properties are specified to assist in
+ proper sequencing of multiple free/busy time replies.
+
+ When used to publish busy time, the "ORGANIZER" property specifies
+ the calendar user associated with the published busy time; the
+ "DTSTART" and "DTEND" properties specify an inclusive time window
+ that surrounds the busy time information; the "FREEBUSY" property
+ specifies the published busy time information; and the "DTSTAMP"
+ property specifies the DATE-TIME that iCalendar object was
+ created.
+
+
+
+
+Desruisseaux Standards Track [Page 60]
+
+RFC 5545 iCalendar September 2009
+
+
+ The "VFREEBUSY" calendar component cannot be nested within another
+ calendar component. Multiple "VFREEBUSY" calendar components can
+ be specified within an iCalendar object. This permits the
+ grouping of free/busy information into logical collections, such
+ as monthly groups of busy time information.
+
+ The "VFREEBUSY" calendar component is intended for use in
+ iCalendar object methods involving requests for free time,
+ requests for busy time, requests for both free and busy, and the
+ associated replies.
+
+ Free/Busy information is represented with the "FREEBUSY" property.
+ This property provides a terse representation of time periods.
+ One or more "FREEBUSY" properties can be specified in the
+ "VFREEBUSY" calendar component.
+
+ When present in a "VFREEBUSY" calendar component, the "DTSTART"
+ and "DTEND" properties SHOULD be specified prior to any "FREEBUSY"
+ properties.
+
+ The recurrence properties ("RRULE", "RDATE", "EXDATE") are not
+ permitted within a "VFREEBUSY" calendar component. Any recurring
+ events are resolved into their individual busy time periods using
+ the "FREEBUSY" property.
+
+ Example: The following is an example of a "VFREEBUSY" calendar
+ component used to request free or busy time information:
+
+ BEGIN:VFREEBUSY
+ UID:19970901T082949Z-FA43EF@example.com
+ ORGANIZER:mailto:jane_doe@example.com
+ ATTENDEE:mailto:john_public@example.com
+ DTSTART:19971015T050000Z
+ DTEND:19971016T050000Z
+ DTSTAMP:19970901T083000Z
+ END:VFREEBUSY
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 61]
+
+RFC 5545 iCalendar September 2009
+
+
+ The following is an example of a "VFREEBUSY" calendar component
+ used to reply to the request with busy time information:
+
+ BEGIN:VFREEBUSY
+ UID:19970901T095957Z-76A912@example.com
+ ORGANIZER:mailto:jane_doe@example.com
+ ATTENDEE:mailto:john_public@example.com
+ DTSTAMP:19970901T100000Z
+ FREEBUSY:19971015T050000Z/PT8H30M,
+ 19971015T160000Z/PT5H30M,19971015T223000Z/PT6H30M
+ URL:http://example.com/pub/busy/jpublic-01.ifb
+ COMMENT:This iCalendar file contains busy time information for
+ the next three months.
+ END:VFREEBUSY
+
+ The following is an example of a "VFREEBUSY" calendar component
+ used to publish busy time information:
+
+ BEGIN:VFREEBUSY
+ UID:19970901T115957Z-76A912@example.com
+ DTSTAMP:19970901T120000Z
+ ORGANIZER:jsmith@example.com
+ DTSTART:19980313T141711Z
+ DTEND:19980410T141711Z
+ FREEBUSY:19980314T233000Z/19980315T003000Z
+ FREEBUSY:19980316T153000Z/19980316T163000Z
+ FREEBUSY:19980318T030000Z/19980318T040000Z
+ URL:http://www.example.com/calendar/busytime/jsmith.ifb
+ END:VFREEBUSY
+
+3.6.5. Time Zone Component
+
+ Component Name: VTIMEZONE
+
+ Purpose: Provide a grouping of component properties that defines a
+ time zone.
+
+ Format Definition: A "VTIMEZONE" calendar component is defined by
+ the following notation:
+
+ timezonec = "BEGIN" ":" "VTIMEZONE" CRLF
+ *(
+ ;
+ ; 'tzid' is REQUIRED, but MUST NOT occur more
+ ; than once.
+ ;
+ tzid /
+ ;
+
+
+
+Desruisseaux Standards Track [Page 62]
+
+RFC 5545 iCalendar September 2009
+
+
+ ; 'last-mod' and 'tzurl' are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ last-mod / tzurl /
+ ;
+ ; One of 'standardc' or 'daylightc' MUST occur
+ ; and each MAY occur more than once.
+ ;
+ standardc / daylightc /
+ ;
+ ; The following are OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ x-prop / iana-prop
+ ;
+ )
+ "END" ":" "VTIMEZONE" CRLF
+
+ standardc = "BEGIN" ":" "STANDARD" CRLF
+ tzprop
+ "END" ":" "STANDARD" CRLF
+
+ daylightc = "BEGIN" ":" "DAYLIGHT" CRLF
+ tzprop
+ "END" ":" "DAYLIGHT" CRLF
+
+ tzprop = *(
+ ;
+ ; The following are REQUIRED,
+ ; but MUST NOT occur more than once.
+ ;
+ dtstart / tzoffsetto / tzoffsetfrom /
+ ;
+ ; The following is OPTIONAL,
+ ; but SHOULD NOT occur more than once.
+ ;
+ rrule /
+ ;
+ ; The following are OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ comment / rdate / tzname / x-prop / iana-prop
+ ;
+ )
+
+ Description: A time zone is unambiguously defined by the set of time
+ measurement rules determined by the governing body for a given
+ geographic area. These rules describe, at a minimum, the base
+
+
+
+Desruisseaux Standards Track [Page 63]
+
+RFC 5545 iCalendar September 2009
+
+
+ offset from UTC for the time zone, often referred to as the
+ Standard Time offset. Many locations adjust their Standard Time
+ forward or backward by one hour, in order to accommodate seasonal
+ changes in number of daylight hours, often referred to as Daylight
+ Saving Time. Some locations adjust their time by a fraction of an
+ hour. Standard Time is also known as Winter Time. Daylight
+ Saving Time is also known as Advanced Time, Summer Time, or Legal
+ Time in certain countries. The following table shows the changes
+ in time zone rules in effect for New York City starting from 1967.
+ Each line represents a description or rule for a particular
+ observance.
+
+ Effective Observance Rule
+
+ +-----------+--------------------------+--------+--------------+
+ | Date | (Date-Time) | Offset | Abbreviation |
+ +-----------+--------------------------+--------+--------------+
+ | 1967-1973 | last Sun in Apr, 02:00 | -0400 | EDT |
+ | | | | |
+ | 1967-2006 | last Sun in Oct, 02:00 | -0500 | EST |
+ | | | | |
+ | 1974-1974 | Jan 6, 02:00 | -0400 | EDT |
+ | | | | |
+ | 1975-1975 | Feb 23, 02:00 | -0400 | EDT |
+ | | | | |
+ | 1976-1986 | last Sun in Apr, 02:00 | -0400 | EDT |
+ | | | | |
+ | 1987-2006 | first Sun in Apr, 02:00 | -0400 | EDT |
+ | | | | |
+ | 2007-* | second Sun in Mar, 02:00 | -0400 | EDT |
+ | | | | |
+ | 2007-* | first Sun in Nov, 02:00 | -0500 | EST |
+ +-----------+--------------------------+--------+--------------+
+
+ Note: The specification of a global time zone registry is not
+ addressed by this document and is left for future study.
+ However, implementers may find the TZ database [TZDB] a useful
+ reference. It is an informal, public-domain collection of time
+ zone information, which is currently being maintained by
+ volunteer Internet participants, and is used in several
+ operating systems. This database contains current and
+ historical time zone information for a wide variety of
+ locations around the globe; it provides a time zone identifier
+ for every unique time zone rule set in actual use since 1970,
+ with historical data going back to the introduction of standard
+ time.
+
+
+
+
+
+Desruisseaux Standards Track [Page 64]
+
+RFC 5545 iCalendar September 2009
+
+
+ Interoperability between two calendaring and scheduling
+ applications, especially for recurring events, to-dos or journal
+ entries, is dependent on the ability to capture and convey date
+ and time information in an unambiguous format. The specification
+ of current time zone information is integral to this behavior.
+
+ If present, the "VTIMEZONE" calendar component defines the set of
+ Standard Time and Daylight Saving Time observances (or rules) for
+ a particular time zone for a given interval of time. The
+ "VTIMEZONE" calendar component cannot be nested within other
+ calendar components. Multiple "VTIMEZONE" calendar components can
+ exist in an iCalendar object. In this situation, each "VTIMEZONE"
+ MUST represent a unique time zone definition. This is necessary
+ for some classes of events, such as airline flights, that start in
+ one time zone and end in another.
+
+ The "VTIMEZONE" calendar component MUST include the "TZID"
+ property and at least one definition of a "STANDARD" or "DAYLIGHT"
+ sub-component. The "STANDARD" or "DAYLIGHT" sub-component MUST
+ include the "DTSTART", "TZOFFSETFROM", and "TZOFFSETTO"
+ properties.
+
+ An individual "VTIMEZONE" calendar component MUST be specified for
+ each unique "TZID" parameter value specified in the iCalendar
+ object. In addition, a "VTIMEZONE" calendar component, referred
+ to by a recurring calendar component, MUST provide valid time zone
+ information for all recurrence instances.
+
+ Each "VTIMEZONE" calendar component consists of a collection of
+ one or more sub-components that describe the rule for a particular
+ observance (either a Standard Time or a Daylight Saving Time
+ observance). The "STANDARD" sub-component consists of a
+ collection of properties that describe Standard Time. The
+ "DAYLIGHT" sub-component consists of a collection of properties
+ that describe Daylight Saving Time. In general, this collection
+ of properties consists of:
+
+ * the first onset DATE-TIME for the observance;
+
+ * the last onset DATE-TIME for the observance, if a last onset is
+ known;
+
+ * the offset to be applied for the observance;
+
+ * a rule that describes the day and time when the observance
+ takes effect;
+
+ * an optional name for the observance.
+
+
+
+Desruisseaux Standards Track [Page 65]
+
+RFC 5545 iCalendar September 2009
+
+
+ For a given time zone, there may be multiple unique definitions of
+ the observances over a period of time. Each observance is
+ described using either a "STANDARD" or "DAYLIGHT" sub-component.
+ The collection of these sub-components is used to describe the
+ time zone for a given period of time. The offset to apply at any
+ given time is found by locating the observance that has the last
+ onset date and time before the time in question, and using the
+ offset value from that observance.
+
+ The top-level properties in a "VTIMEZONE" calendar component are:
+
+ The mandatory "TZID" property is a text value that uniquely
+ identifies the "VTIMEZONE" calendar component within the scope of
+ an iCalendar object.
+
+ The optional "LAST-MODIFIED" property is a UTC value that
+ specifies the date and time that this time zone definition was
+ last updated.
+
+ The optional "TZURL" property is a url value that points to a
+ published "VTIMEZONE" definition. "TZURL" SHOULD refer to a
+ resource that is accessible by anyone who might need to interpret
+ the object. This SHOULD NOT normally be a "file" URL or other URL
+ that is not widely accessible.
+
+ The collection of properties that are used to define the
+ "STANDARD" and "DAYLIGHT" sub-components include:
+
+ The mandatory "DTSTART" property gives the effective onset date
+ and local time for the time zone sub-component definition.
+ "DTSTART" in this usage MUST be specified as a date with a local
+ time value.
+
+ The mandatory "TZOFFSETFROM" property gives the UTC offset that is
+ in use when the onset of this time zone observance begins.
+ "TZOFFSETFROM" is combined with "DTSTART" to define the effective
+ onset for the time zone sub-component definition. For example,
+ the following represents the time at which the observance of
+ Standard Time took effect in Fall 1967 for New York City:
+
+ DTSTART:19671029T020000
+
+ TZOFFSETFROM:-0400
+
+ The mandatory "TZOFFSETTO" property gives the UTC offset for the
+ time zone sub-component (Standard Time or Daylight Saving Time)
+ when this observance is in use.
+
+
+
+
+Desruisseaux Standards Track [Page 66]
+
+RFC 5545 iCalendar September 2009
+
+
+ The optional "TZNAME" property is the customary name for the time
+ zone. This could be used for displaying dates.
+
+ The onset DATE-TIME values for the observance defined by the time
+ zone sub-component is defined by the "DTSTART", "RRULE", and
+ "RDATE" properties.
+
+ The "RRULE" property defines the recurrence rule for the onset of
+ the observance defined by this time zone sub-component. Some
+ specific requirements for the usage of "RRULE" for this purpose
+ include:
+
+ * If observance is known to have an effective end date, the
+ "UNTIL" recurrence rule parameter MUST be used to specify the
+ last valid onset of this observance (i.e., the UNTIL DATE-TIME
+ will be equal to the last instance generated by the recurrence
+ pattern). It MUST be specified in UTC time.
+
+ * The "DTSTART" and the "TZOFFSETFROM" properties MUST be used
+ when generating the onset DATE-TIME values (instances) from the
+ "RRULE".
+
+ The "RDATE" property can also be used to define the onset of the
+ observance by giving the individual onset date and times. "RDATE"
+ in this usage MUST be specified as a date with local time value,
+ relative to the UTC offset specified in the "TZOFFSETFROM"
+ property.
+
+ The optional "COMMENT" property is also allowed for descriptive
+ explanatory text.
+
+ Example: The following are examples of the "VTIMEZONE" calendar
+ component:
+
+ This is an example showing all the time zone rules for New York
+ City since April 30, 1967 at 03:00:00 EDT.
+
+ BEGIN:VTIMEZONE
+ TZID:America/New_York
+ LAST-MODIFIED:20050809T050000Z
+ BEGIN:DAYLIGHT
+ DTSTART:19670430T020000
+ RRULE:FREQ=YEARLY;BYMONTH=4;BYDAY=-1SU;UNTIL=19730429T070000Z
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ BEGIN:STANDARD
+
+
+
+Desruisseaux Standards Track [Page 67]
+
+RFC 5545 iCalendar September 2009
+
+
+ DTSTART:19671029T020000
+ RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU;UNTIL=20061029T060000Z
+ TZOFFSETFROM:-0400
+ TZOFFSETTO:-0500
+ TZNAME:EST
+ END:STANDARD
+ BEGIN:DAYLIGHT
+ DTSTART:19740106T020000
+ RDATE:19750223T020000
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ BEGIN:DAYLIGHT
+ DTSTART:19760425T020000
+ RRULE:FREQ=YEARLY;BYMONTH=4;BYDAY=-1SU;UNTIL=19860427T070000Z
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ BEGIN:DAYLIGHT
+ DTSTART:19870405T020000
+ RRULE:FREQ=YEARLY;BYMONTH=4;BYDAY=1SU;UNTIL=20060402T070000Z
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ BEGIN:DAYLIGHT
+ DTSTART:20070311T020000
+ RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ BEGIN:STANDARD
+ DTSTART:20071104T020000
+ RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
+ TZOFFSETFROM:-0400
+ TZOFFSETTO:-0500
+ TZNAME:EST
+ END:STANDARD
+ END:VTIMEZONE
+
+ This is an example showing time zone information for New York City
+ using only the "DTSTART" property. Note that this is only
+ suitable for a recurring event that starts on or later than March
+ 11, 2007 at 03:00:00 EDT (i.e., the earliest effective transition
+ date and time) and ends no later than March 9, 2008 at 01:59:59
+
+
+
+Desruisseaux Standards Track [Page 68]
+
+RFC 5545 iCalendar September 2009
+
+
+ EST (i.e., latest valid date and time for EST in this scenario).
+ For example, this can be used for a recurring event that occurs
+ every Friday, 8:00 A.M.-9:00 A.M., starting June 1, 2007, ending
+ December 31, 2007,
+
+ BEGIN:VTIMEZONE
+ TZID:America/New_York
+ LAST-MODIFIED:20050809T050000Z
+ BEGIN:STANDARD
+ DTSTART:20071104T020000
+ TZOFFSETFROM:-0400
+ TZOFFSETTO:-0500
+ TZNAME:EST
+ END:STANDARD
+ BEGIN:DAYLIGHT
+ DTSTART:20070311T020000
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ END:VTIMEZONE
+
+ This is a simple example showing the current time zone rules for
+ New York City using a "RRULE" recurrence pattern. Note that there
+ is no effective end date to either of the Standard Time or
+ Daylight Time rules. This information would be valid for a
+ recurring event starting today and continuing indefinitely.
+
+ BEGIN:VTIMEZONE
+ TZID:America/New_York
+ LAST-MODIFIED:20050809T050000Z
+ TZURL:http://zones.example.com/tz/America-New_York.ics
+ BEGIN:STANDARD
+ DTSTART:20071104T020000
+ RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
+ TZOFFSETFROM:-0400
+ TZOFFSETTO:-0500
+ TZNAME:EST
+ END:STANDARD
+ BEGIN:DAYLIGHT
+ DTSTART:20070311T020000
+ RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ END:VTIMEZONE
+
+
+
+
+Desruisseaux Standards Track [Page 69]
+
+RFC 5545 iCalendar September 2009
+
+
+ This is an example showing a set of rules for a fictitious time
+ zone where the Daylight Time rule has an effective end date (i.e.,
+ after that date, Daylight Time is no longer observed).
+
+ BEGIN:VTIMEZONE
+ TZID:Fictitious
+ LAST-MODIFIED:19870101T000000Z
+ BEGIN:STANDARD
+ DTSTART:19671029T020000
+ RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+ TZOFFSETFROM:-0400
+ TZOFFSETTO:-0500
+ TZNAME:EST
+ END:STANDARD
+ BEGIN:DAYLIGHT
+ DTSTART:19870405T020000
+ RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000Z
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ END:VTIMEZONE
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 70]
+
+RFC 5545 iCalendar September 2009
+
+
+ This is an example showing a set of rules for a fictitious time
+ zone where the first Daylight Time rule has an effective end date.
+ There is a second Daylight Time rule that picks up where the other
+ left off.
+
+ BEGIN:VTIMEZONE
+ TZID:Fictitious
+ LAST-MODIFIED:19870101T000000Z
+ BEGIN:STANDARD
+ DTSTART:19671029T020000
+ RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+ TZOFFSETFROM:-0400
+ TZOFFSETTO:-0500
+ TZNAME:EST
+ END:STANDARD
+ BEGIN:DAYLIGHT
+ DTSTART:19870405T020000
+ RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000Z
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ BEGIN:DAYLIGHT
+ DTSTART:19990424T020000
+ RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=4
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+ TZNAME:EDT
+ END:DAYLIGHT
+ END:VTIMEZONE
+
+3.6.6. Alarm Component
+
+ Component Name: VALARM
+
+ Purpose: Provide a grouping of component properties that define an
+ alarm.
+
+ Format Definition: A "VALARM" calendar component is defined by the
+ following notation:
+
+ alarmc = "BEGIN" ":" "VALARM" CRLF
+ (audioprop / dispprop / emailprop)
+ "END" ":" "VALARM" CRLF
+
+ audioprop = *(
+ ;
+ ; 'action' and 'trigger' are both REQUIRED,
+
+
+
+Desruisseaux Standards Track [Page 71]
+
+RFC 5545 iCalendar September 2009
+
+
+ ; but MUST NOT occur more than once.
+ ;
+ action / trigger /
+ ;
+ ; 'duration' and 'repeat' are both OPTIONAL,
+ ; and MUST NOT occur more than once each;
+ ; but if one occurs, so MUST the other.
+ ;
+ duration / repeat /
+ ;
+ ; The following is OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ attach /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ x-prop / iana-prop
+ ;
+ )
+
+ dispprop = *(
+ ;
+ ; The following are REQUIRED,
+ ; but MUST NOT occur more than once.
+ ;
+ action / description / trigger /
+ ;
+ ; 'duration' and 'repeat' are both OPTIONAL,
+ ; and MUST NOT occur more than once each;
+ ; but if one occurs, so MUST the other.
+ ;
+ duration / repeat /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ x-prop / iana-prop
+ ;
+ )
+
+ emailprop = *(
+ ;
+ ; The following are all REQUIRED,
+ ; but MUST NOT occur more than once.
+ ;
+ action / description / trigger / summary /
+
+
+
+Desruisseaux Standards Track [Page 72]
+
+RFC 5545 iCalendar September 2009
+
+
+ ;
+ ; The following is REQUIRED,
+ ; and MAY occur more than once.
+ ;
+ attendee /
+ ;
+ ; 'duration' and 'repeat' are both OPTIONAL,
+ ; and MUST NOT occur more than once each;
+ ; but if one occurs, so MUST the other.
+ ;
+ duration / repeat /
+ ;
+ ; The following are OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ attach / x-prop / iana-prop
+ ;
+ )
+
+ Description: A "VALARM" calendar component is a grouping of
+ component properties that is a reminder or alarm for an event or a
+ to-do. For example, it may be used to define a reminder for a
+ pending event or an overdue to-do.
+
+ The "VALARM" calendar component MUST include the "ACTION" and
+ "TRIGGER" properties. The "ACTION" property further constrains
+ the "VALARM" calendar component in the following ways:
+
+ When the action is "AUDIO", the alarm can also include one and
+ only one "ATTACH" property, which MUST point to a sound resource,
+ which is rendered when the alarm is triggered.
+
+ When the action is "DISPLAY", the alarm MUST also include a
+ "DESCRIPTION" property, which contains the text to be displayed
+ when the alarm is triggered.
+
+ When the action is "EMAIL", the alarm MUST include a "DESCRIPTION"
+ property, which contains the text to be used as the message body,
+ a "SUMMARY" property, which contains the text to be used as the
+ message subject, and one or more "ATTENDEE" properties, which
+ contain the email address of attendees to receive the message. It
+ can also include one or more "ATTACH" properties, which are
+ intended to be sent as message attachments. When the alarm is
+ triggered, the email message is sent.
+
+ The "VALARM" calendar component MUST only appear within either a
+ "VEVENT" or "VTODO" calendar component. "VALARM" calendar
+ components cannot be nested. Multiple mutually independent
+
+
+
+Desruisseaux Standards Track [Page 73]
+
+RFC 5545 iCalendar September 2009
+
+
+ "VALARM" calendar components can be specified for a single
+ "VEVENT" or "VTODO" calendar component.
+
+ The "TRIGGER" property specifies when the alarm will be triggered.
+ The "TRIGGER" property specifies a duration prior to the start of
+ an event or a to-do. The "TRIGGER" edge may be explicitly set to
+ be relative to the "START" or "END" of the event or to-do with the
+ "RELATED" parameter of the "TRIGGER" property. The "TRIGGER"
+ property value type can alternatively be set to an absolute
+ calendar date with UTC time.
+
+ In an alarm set to trigger on the "START" of an event or to-do,
+ the "DTSTART" property MUST be present in the associated event or
+ to-do. In an alarm in a "VEVENT" calendar component set to
+ trigger on the "END" of the event, either the "DTEND" property
+ MUST be present, or the "DTSTART" and "DURATION" properties MUST
+ both be present. In an alarm in a "VTODO" calendar component set
+ to trigger on the "END" of the to-do, either the "DUE" property
+ MUST be present, or the "DTSTART" and "DURATION" properties MUST
+ both be present.
+
+ The alarm can be defined such that it triggers repeatedly. A
+ definition of an alarm with a repeating trigger MUST include both
+ the "DURATION" and "REPEAT" properties. The "DURATION" property
+ specifies the delay period, after which the alarm will repeat.
+ The "REPEAT" property specifies the number of additional
+ repetitions that the alarm will be triggered. This repetition
+ count is in addition to the initial triggering of the alarm. Both
+ of these properties MUST be present in order to specify a
+ repeating alarm. If one of these two properties is absent, then
+ the alarm will not repeat beyond the initial trigger.
+
+ The "ACTION" property is used within the "VALARM" calendar
+ component to specify the type of action invoked when the alarm is
+ triggered. The "VALARM" properties provide enough information for
+ a specific action to be invoked. It is typically the
+ responsibility of a "Calendar User Agent" (CUA) to deliver the
+ alarm in the specified fashion. An "ACTION" property value of
+ AUDIO specifies an alarm that causes a sound to be played to alert
+ the user; DISPLAY specifies an alarm that causes a text message to
+ be displayed to the user; and EMAIL specifies an alarm that causes
+ an electronic email message to be delivered to one or more email
+ addresses.
+
+ In an AUDIO alarm, if the optional "ATTACH" property is included,
+ it MUST specify an audio sound resource. The intention is that
+ the sound will be played as the alarm effect. If an "ATTACH"
+ property is specified that does not refer to a sound resource, or
+
+
+
+Desruisseaux Standards Track [Page 74]
+
+RFC 5545 iCalendar September 2009
+
+
+ if the specified sound resource cannot be rendered (because its
+ format is unsupported, or because it cannot be retrieved), then
+ the CUA or other entity responsible for playing the sound may
+ choose a fallback action, such as playing a built-in default
+ sound, or playing no sound at all.
+
+ In a DISPLAY alarm, the intended alarm effect is for the text
+ value of the "DESCRIPTION" property to be displayed to the user.
+
+ In an EMAIL alarm, the intended alarm effect is for an email
+ message to be composed and delivered to all the addresses
+ specified by the "ATTENDEE" properties in the "VALARM" calendar
+ component. The "DESCRIPTION" property of the "VALARM" calendar
+ component MUST be used as the body text of the message, and the
+ "SUMMARY" property MUST be used as the subject text. Any "ATTACH"
+ properties in the "VALARM" calendar component SHOULD be sent as
+ attachments to the message.
+
+ Note: Implementations should carefully consider whether they
+ accept alarm components from untrusted sources, e.g., when
+ importing calendar objects from external sources. One
+ reasonable policy is to always ignore alarm components that the
+ calendar user has not set herself, or at least ask for
+ confirmation in such a case.
+
+ Example: The following example is for a "VALARM" calendar component
+ that specifies an audio alarm that will sound at a precise time
+ and repeat 4 more times at 15-minute intervals:
+
+ BEGIN:VALARM
+ TRIGGER;VALUE=DATE-TIME:19970317T133000Z
+ REPEAT:4
+ DURATION:PT15M
+ ACTION:AUDIO
+ ATTACH;FMTTYPE=audio/basic:ftp://example.com/pub/
+ sounds/bell-01.aud
+ END:VALARM
+
+ The following example is for a "VALARM" calendar component that
+ specifies a display alarm that will trigger 30 minutes before the
+ scheduled start of the event or of the to-do it is associated with
+ and will repeat 2 more times at 15-minute intervals:
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 75]
+
+RFC 5545 iCalendar September 2009
+
+
+ BEGIN:VALARM
+ TRIGGER:-PT30M
+ REPEAT:2
+ DURATION:PT15M
+ ACTION:DISPLAY
+ DESCRIPTION:Breakfast meeting with executive\n
+ team at 8:30 AM EST.
+ END:VALARM
+
+ The following example is for a "VALARM" calendar component that
+ specifies an email alarm that will trigger 2 days before the
+ scheduled due DATE-TIME of a to-do with which it is associated.
+ It does not repeat. The email has a subject, body, and attachment
+ link.
+
+ BEGIN:VALARM
+ TRIGGER;RELATED=END:-P2D
+ ACTION:EMAIL
+ ATTENDEE:mailto:john_doe@example.com
+ SUMMARY:*** REMINDER: SEND AGENDA FOR WEEKLY STAFF MEETING ***
+ DESCRIPTION:A draft agenda needs to be sent out to the attendees
+ to the weekly managers meeting (MGR-LIST). Attached is a
+ pointer the document template for the agenda file.
+ ATTACH;FMTTYPE=application/msword:http://example.com/
+ templates/agenda.doc
+ END:VALARM
+
+3.7. Calendar Properties
+
+ The Calendar Properties are attributes that apply to the iCalendar
+ object, as a whole. These properties do not appear within a calendar
+ component. They SHOULD be specified after the "BEGIN:VCALENDAR"
+ delimiter string and prior to any calendar component.
+
+3.7.1. Calendar Scale
+
+ Property Name: CALSCALE
+
+ Purpose: This property defines the calendar scale used for the
+ calendar information specified in the iCalendar object.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified once in an iCalendar
+ object. The default value is "GREGORIAN".
+
+
+
+Desruisseaux Standards Track [Page 76]
+
+RFC 5545 iCalendar September 2009
+
+
+ Description: This memo is based on the Gregorian calendar scale.
+ The Gregorian calendar scale is assumed if this property is not
+ specified in the iCalendar object. It is expected that other
+ calendar scales will be defined in other specifications or by
+ future versions of this memo.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ calscale = "CALSCALE" calparam ":" calvalue CRLF
+
+ calparam = *(";" other-param)
+
+ calvalue = "GREGORIAN"
+
+ Example: The following is an example of this property:
+
+ CALSCALE:GREGORIAN
+
+3.7.2. Method
+
+ Property Name: METHOD
+
+ Purpose: This property defines the iCalendar object method
+ associated with the calendar object.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified once in an iCalendar
+ object.
+
+ Description: When used in a MIME message entity, the value of this
+ property MUST be the same as the Content-Type "method" parameter
+ value. If either the "METHOD" property or the Content-Type
+ "method" parameter is specified, then the other MUST also be
+ specified.
+
+ No methods are defined by this specification. This is the subject
+ of other specifications, such as the iCalendar Transport-
+ independent Interoperability Protocol (iTIP) defined by [2446bis].
+
+ If this property is not present in the iCalendar object, then a
+ scheduling transaction MUST NOT be assumed. In such cases, the
+ iCalendar object is merely being used to transport a snapshot of
+
+
+
+
+Desruisseaux Standards Track [Page 77]
+
+RFC 5545 iCalendar September 2009
+
+
+ some calendar information; without the intention of conveying a
+ scheduling semantic.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ method = "METHOD" metparam ":" metvalue CRLF
+
+ metparam = *(";" other-param)
+
+ metvalue = iana-token
+
+ Example: The following is a hypothetical example of this property to
+ convey that the iCalendar object is a scheduling request:
+
+ METHOD:REQUEST
+
+3.7.3. Product Identifier
+
+ Property Name: PRODID
+
+ Purpose: This property specifies the identifier for the product that
+ created the iCalendar object.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: The property MUST be specified once in an iCalendar
+ object.
+
+ Description: The vendor of the implementation SHOULD assure that
+ this is a globally unique identifier; using some technique such as
+ an FPI value, as defined in [ISO.9070.1991].
+
+ This property SHOULD NOT be used to alter the interpretation of an
+ iCalendar object beyond the semantics specified in this memo. For
+ example, it is not to be used to further the understanding of non-
+ standard properties.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ prodid = "PRODID" pidparam ":" pidvalue CRLF
+
+ pidparam = *(";" other-param)
+
+
+
+
+Desruisseaux Standards Track [Page 78]
+
+RFC 5545 iCalendar September 2009
+
+
+ pidvalue = text
+ ;Any text that describes the product and version
+ ;and that is generally assured of being unique.
+
+ Example: The following is an example of this property. It does not
+ imply that English is the default language.
+
+ PRODID:-//ABC Corporation//NONSGML My Product//EN
+
+3.7.4. Version
+
+ Property Name: VERSION
+
+ Purpose: This property specifies the identifier corresponding to the
+ highest version number or the minimum and maximum range of the
+ iCalendar specification that is required in order to interpret the
+ iCalendar object.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property MUST be specified once in an iCalendar
+ object.
+
+ Description: A value of "2.0" corresponds to this memo.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ version = "VERSION" verparam ":" vervalue CRLF
+
+ verparam = *(";" other-param)
+
+ vervalue = "2.0" ;This memo
+ / maxver
+ / (minver ";" maxver)
+
+ minver = <A IANA-registered iCalendar version identifier>
+ ;Minimum iCalendar version needed to parse the iCalendar object.
+
+ maxver = <A IANA-registered iCalendar version identifier>
+ ;Maximum iCalendar version needed to parse the iCalendar object.
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 79]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example: The following is an example of this property:
+
+ VERSION:2.0
+
+3.8. Component Properties
+
+ The following properties can appear within calendar components, as
+ specified by each component property definition.
+
+3.8.1. Descriptive Component Properties
+
+ The following properties specify descriptive information about
+ calendar components.
+
+3.8.1.1. Attachment
+
+ Property Name: ATTACH
+
+ Purpose: This property provides the capability to associate a
+ document object with a calendar component.
+
+ Value Type: The default value type for this property is URI. The
+ value type can also be set to BINARY to indicate inline binary
+ encoded content information.
+
+ Property Parameters: IANA, non-standard, inline encoding, and value
+ data type property parameters can be specified on this property.
+ The format type parameter can be specified on this property and is
+ RECOMMENDED for inline binary encoded content information.
+
+ Conformance: This property can be specified multiple times in a
+ "VEVENT", "VTODO", "VJOURNAL", or "VALARM" calendar component with
+ the exception of AUDIO alarm that only allows this property to
+ occur once.
+
+ Description: This property is used in "VEVENT", "VTODO", and
+ "VJOURNAL" calendar components to associate a resource (e.g.,
+ document) with the calendar component. This property is used in
+ "VALARM" calendar components to specify an audio sound resource or
+ an email message attachment. This property can be specified as a
+ URI pointing to a resource or as inline binary encoded content.
+
+ When this property is specified as inline binary encoded content,
+ calendar applications MAY attempt to guess the media type of the
+ resource via inspection of its content if and only if the media
+ type of the resource is not given by the "FMTTYPE" parameter. If
+ the media type remains unknown, calendar applications SHOULD treat
+ it as type "application/octet-stream".
+
+
+
+Desruisseaux Standards Track [Page 80]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ attach = "ATTACH" attachparam ( ":" uri ) /
+ (
+ ";" "ENCODING" "=" "BASE64"
+ ";" "VALUE" "=" "BINARY"
+ ":" binary
+ )
+ CRLF
+
+ attachparam = *(
+ ;
+ ; The following is OPTIONAL for a URI value,
+ ; RECOMMENDED for a BINARY value,
+ ; and MUST NOT occur more than once.
+ ;
+ (";" fmttypeparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following are examples of this property:
+
+ ATTACH:CID:jsmith.part3.960817T083000.xyzMail@example.com
+
+ ATTACH;FMTTYPE=application/postscript:ftp://example.com/pub/
+ reports/r-960812.ps
+
+3.8.1.2. Categories
+
+ Property Name: CATEGORIES
+
+ Purpose: This property defines the categories for a calendar
+ component.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, and language property
+ parameters can be specified on this property.
+
+ Conformance: The property can be specified within "VEVENT", "VTODO",
+ or "VJOURNAL" calendar components.
+
+
+
+
+Desruisseaux Standards Track [Page 81]
+
+RFC 5545 iCalendar September 2009
+
+
+ Description: This property is used to specify categories or subtypes
+ of the calendar component. The categories are useful in searching
+ for a calendar component of a particular type and category.
+ Within the "VEVENT", "VTODO", or "VJOURNAL" calendar components,
+ more than one category can be specified as a COMMA-separated list
+ of categories.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ categories = "CATEGORIES" catparam ":" text *("," text)
+ CRLF
+
+ catparam = *(
+ ;
+ ; The following is OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" languageparam ) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following are examples of this property:
+
+ CATEGORIES:APPOINTMENT,EDUCATION
+
+ CATEGORIES:MEETING
+
+3.8.1.3. Classification
+
+ Property Name: CLASS
+
+ Purpose: This property defines the access classification for a
+ calendar component.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: The property can be specified once in a "VEVENT",
+ "VTODO", or "VJOURNAL" calendar components.
+
+
+
+
+Desruisseaux Standards Track [Page 82]
+
+RFC 5545 iCalendar September 2009
+
+
+ Description: An access classification is only one component of the
+ general security system within a calendar application. It
+ provides a method of capturing the scope of the access the
+ calendar owner intends for information within an individual
+ calendar entry. The access classification of an individual
+ iCalendar component is useful when measured along with the other
+ security components of a calendar system (e.g., calendar user
+ authentication, authorization, access rights, access role, etc.).
+ Hence, the semantics of the individual access classifications
+ cannot be completely defined by this memo alone. Additionally,
+ due to the "blind" nature of most exchange processes using this
+ memo, these access classifications cannot serve as an enforcement
+ statement for a system receiving an iCalendar object. Rather,
+ they provide a method for capturing the intention of the calendar
+ owner for the access to the calendar component. If not specified
+ in a component that allows this property, the default value is
+ PUBLIC. Applications MUST treat x-name and iana-token values they
+ don't recognize the same way as they would the PRIVATE value.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ class = "CLASS" classparam ":" classvalue CRLF
+
+ classparam = *(";" other-param)
+
+ classvalue = "PUBLIC" / "PRIVATE" / "CONFIDENTIAL" / iana-token
+ / x-name
+ ;Default is PUBLIC
+
+ Example: The following is an example of this property:
+
+ CLASS:PUBLIC
+
+3.8.1.4. Comment
+
+ Property Name: COMMENT
+
+ Purpose: This property specifies non-processing information intended
+ to provide a comment to the calendar user.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, alternate text
+ representation, and language property parameters can be specified
+ on this property.
+
+
+
+
+
+Desruisseaux Standards Track [Page 83]
+
+RFC 5545 iCalendar September 2009
+
+
+ Conformance: This property can be specified multiple times in
+ "VEVENT", "VTODO", "VJOURNAL", and "VFREEBUSY" calendar components
+ as well as in the "STANDARD" and "DAYLIGHT" sub-components.
+
+ Description: This property is used to specify a comment to the
+ calendar user.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ comment = "COMMENT" commparam ":" text CRLF
+
+ commparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" altrepparam) / (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following is an example of this property:
+
+ COMMENT:The meeting really needs to include both ourselves
+ and the customer. We can't hold this meeting without them.
+ As a matter of fact\, the venue for the meeting ought to be at
+ their site. - - John
+
+3.8.1.5. Description
+
+ Property Name: DESCRIPTION
+
+ Purpose: This property provides a more complete description of the
+ calendar component than that provided by the "SUMMARY" property.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, alternate text
+ representation, and language property parameters can be specified
+ on this property.
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 84]
+
+RFC 5545 iCalendar September 2009
+
+
+ Conformance: The property can be specified in the "VEVENT", "VTODO",
+ "VJOURNAL", or "VALARM" calendar components. The property can be
+ specified multiple times only within a "VJOURNAL" calendar
+ component.
+
+ Description: This property is used in the "VEVENT" and "VTODO" to
+ capture lengthy textual descriptions associated with the activity.
+
+ This property is used in the "VJOURNAL" calendar component to
+ capture one or more textual journal entries.
+
+ This property is used in the "VALARM" calendar component to
+ capture the display text for a DISPLAY category of alarm, and to
+ capture the body text for an EMAIL category of alarm.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ description = "DESCRIPTION" descparam ":" text CRLF
+
+ descparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" altrepparam) / (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following is an example of this property with formatted
+ line breaks in the property value:
+
+ DESCRIPTION:Meeting to provide technical review for "Phoenix"
+ design.\nHappy Face Conference Room. Phoenix design team
+ MUST attend this meeting.\nRSVP to team leader.
+
+3.8.1.6. Geographic Position
+
+ Property Name: GEO
+
+ Purpose: This property specifies information related to the global
+ position for the activity specified by a calendar component.
+
+
+
+
+Desruisseaux Standards Track [Page 85]
+
+RFC 5545 iCalendar September 2009
+
+
+ Value Type: FLOAT. The value MUST be two SEMICOLON-separated FLOAT
+ values.
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified in "VEVENT" or "VTODO"
+ calendar components.
+
+ Description: This property value specifies latitude and longitude,
+ in that order (i.e., "LAT LON" ordering). The longitude
+ represents the location east or west of the prime meridian as a
+ positive or negative real number, respectively. The longitude and
+ latitude values MAY be specified up to six decimal places, which
+ will allow for accuracy to within one meter of geographical
+ position. Receiving applications MUST accept values of this
+ precision and MAY truncate values of greater precision.
+
+ Values for latitude and longitude shall be expressed as decimal
+ fractions of degrees. Whole degrees of latitude shall be
+ represented by a two-digit decimal number ranging from 0 through
+ 90. Whole degrees of longitude shall be represented by a decimal
+ number ranging from 0 through 180. When a decimal fraction of a
+ degree is specified, it shall be separated from the whole number
+ of degrees by a decimal point.
+
+ Latitudes north of the equator shall be specified by a plus sign
+ (+), or by the absence of a minus sign (-), preceding the digits
+ designating degrees. Latitudes south of the Equator shall be
+ designated by a minus sign (-) preceding the digits designating
+ degrees. A point on the Equator shall be assigned to the Northern
+ Hemisphere.
+
+ Longitudes east of the prime meridian shall be specified by a plus
+ sign (+), or by the absence of a minus sign (-), preceding the
+ digits designating degrees. Longitudes west of the meridian shall
+ be designated by minus sign (-) preceding the digits designating
+ degrees. A point on the prime meridian shall be assigned to the
+ Eastern Hemisphere. A point on the 180th meridian shall be
+ assigned to the Western Hemisphere. One exception to this last
+ convention is permitted. For the special condition of describing
+ a band of latitude around the earth, the East Bounding Coordinate
+ data element shall be assigned the value +180 (180) degrees.
+
+ Any spatial address with a latitude of +90 (90) or -90 degrees
+ will specify the position at the North or South Pole,
+ respectively. The component for longitude may have any legal
+ value.
+
+
+
+Desruisseaux Standards Track [Page 86]
+
+RFC 5545 iCalendar September 2009
+
+
+ With the exception of the special condition described above, this
+ form is specified in [ANSI INCITS 61-1986].
+
+ The simple formula for converting degrees-minutes-seconds into
+ decimal degrees is:
+
+ decimal = degrees + minutes/60 + seconds/3600.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ geo = "GEO" geoparam ":" geovalue CRLF
+
+ geoparam = *(";" other-param)
+
+ geovalue = float ";" float
+ ;Latitude and Longitude components
+
+ Example: The following is an example of this property:
+
+ GEO:37.386013;-122.082932
+
+3.8.1.7. Location
+
+ Property Name: LOCATION
+
+ Purpose: This property defines the intended venue for the activity
+ defined by a calendar component.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, alternate text
+ representation, and language property parameters can be specified
+ on this property.
+
+ Conformance: This property can be specified in "VEVENT" or "VTODO"
+ calendar component.
+
+ Description: Specific venues such as conference or meeting rooms may
+ be explicitly specified using this property. An alternate
+ representation may be specified that is a URI that points to
+ directory information with more structured specification of the
+ location. For example, the alternate representation may specify
+ either an LDAP URL [RFC4516] pointing to an LDAP server entry or a
+ CID URL [RFC2392] pointing to a MIME body part containing a
+ Virtual-Information Card (vCard) [RFC2426] for the location.
+
+
+
+
+
+Desruisseaux Standards Track [Page 87]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ location = "LOCATION" locparam ":" text CRLF
+
+ locparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" altrepparam) / (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following are some examples of this property:
+
+ LOCATION:Conference Room - F123\, Bldg. 002
+
+ LOCATION;ALTREP="http://xyzcorp.com/conf-rooms/f123.vcf":
+ Conference Room - F123\, Bldg. 002
+
+3.8.1.8. Percent Complete
+
+ Property Name: PERCENT-COMPLETE
+
+ Purpose: This property is used by an assignee or delegatee of a
+ to-do to convey the percent completion of a to-do to the
+ "Organizer".
+
+ Value Type: INTEGER
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified once in a "VTODO"
+ calendar component.
+
+ Description: The property value is a positive integer between 0 and
+ 100. A value of "0" indicates the to-do has not yet been started.
+ A value of "100" indicates that the to-do has been completed.
+ Integer values in between indicate the percent partially complete.
+
+
+
+
+
+Desruisseaux Standards Track [Page 88]
+
+RFC 5545 iCalendar September 2009
+
+
+ When a to-do is assigned to multiple individuals, the property
+ value indicates the percent complete for that portion of the to-do
+ assigned to the assignee or delegatee. For example, if a to-do is
+ assigned to both individuals "A" and "B". A reply from "A" with a
+ percent complete of "70" indicates that "A" has completed 70% of
+ the to-do assigned to them. A reply from "B" with a percent
+ complete of "50" indicates "B" has completed 50% of the to-do
+ assigned to them.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ percent = "PERCENT-COMPLETE" pctparam ":" integer CRLF
+
+ pctparam = *(";" other-param)
+
+ Example: The following is an example of this property to show 39%
+ completion:
+
+ PERCENT-COMPLETE:39
+
+3.8.1.9. Priority
+
+ Property Name: PRIORITY
+
+ Purpose: This property defines the relative priority for a calendar
+ component.
+
+ Value Type: INTEGER
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified in "VEVENT" and "VTODO"
+ calendar components.
+
+ Description: This priority is specified as an integer in the range 0
+ to 9. A value of 0 specifies an undefined priority. A value of 1
+ is the highest priority. A value of 2 is the second highest
+ priority. Subsequent numbers specify a decreasing ordinal
+ priority. A value of 9 is the lowest priority.
+
+ A CUA with a three-level priority scheme of "HIGH", "MEDIUM", and
+ "LOW" is mapped into this property such that a property value in
+ the range of 1 to 4 specifies "HIGH" priority. A value of 5 is
+ the normal or "MEDIUM" priority. A value in the range of 6 to 9
+ is "LOW" priority.
+
+
+
+
+Desruisseaux Standards Track [Page 89]
+
+RFC 5545 iCalendar September 2009
+
+
+ A CUA with a priority schema of "A1", "A2", "A3", "B1", "B2", ...,
+ "C3" is mapped into this property such that a property value of 1
+ specifies "A1", a property value of 2 specifies "A2", a property
+ value of 3 specifies "A3", and so forth up to a property value of
+ 9 specifies "C3".
+
+ Other integer values are reserved for future use.
+
+ Within a "VEVENT" calendar component, this property specifies a
+ priority for the event. This property may be useful when more
+ than one event is scheduled for a given time period.
+
+ Within a "VTODO" calendar component, this property specified a
+ priority for the to-do. This property is useful in prioritizing
+ multiple action items for a given time period.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ priority = "PRIORITY" prioparam ":" priovalue CRLF
+ ;Default is zero (i.e., undefined).
+
+ prioparam = *(";" other-param)
+
+ priovalue = integer ;Must be in the range [0..9]
+ ; All other values are reserved for future use.
+
+ Example: The following is an example of a property with the highest
+ priority:
+
+ PRIORITY:1
+
+ The following is an example of a property with a next highest
+ priority:
+
+ PRIORITY:2
+
+ The following is an example of a property with no priority. This
+ is equivalent to not specifying the "PRIORITY" property:
+
+ PRIORITY:0
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 90]
+
+RFC 5545 iCalendar September 2009
+
+
+3.8.1.10. Resources
+
+ Property Name: RESOURCES
+
+ Purpose: This property defines the equipment or resources
+ anticipated for an activity specified by a calendar component.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, alternate text
+ representation, and language property parameters can be specified
+ on this property.
+
+ Conformance: This property can be specified once in "VEVENT" or
+ "VTODO" calendar component.
+
+ Description: The property value is an arbitrary text. More than one
+ resource can be specified as a COMMA-separated list of resources.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ resources = "RESOURCES" resrcparam ":" text *("," text) CRLF
+
+ resrcparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" altrepparam) / (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following is an example of this property:
+
+ RESOURCES:EASEL,PROJECTOR,VCR
+
+ RESOURCES;LANGUAGE=fr:Nettoyeur haute pression
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 91]
+
+RFC 5545 iCalendar September 2009
+
+
+3.8.1.11. Status
+
+ Property Name: STATUS
+
+ Purpose: This property defines the overall status or confirmation
+ for the calendar component.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified once in "VEVENT",
+ "VTODO", or "VJOURNAL" calendar components.
+
+ Description: In a group-scheduled calendar component, the property
+ is used by the "Organizer" to provide a confirmation of the event
+ to the "Attendees". For example in a "VEVENT" calendar component,
+ the "Organizer" can indicate that a meeting is tentative,
+ confirmed, or cancelled. In a "VTODO" calendar component, the
+ "Organizer" can indicate that an action item needs action, is
+ completed, is in process or being worked on, or has been
+ cancelled. In a "VJOURNAL" calendar component, the "Organizer"
+ can indicate that a journal entry is draft, final, or has been
+ cancelled or removed.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ status = "STATUS" statparam ":" statvalue CRLF
+
+ statparam = *(";" other-param)
+
+ statvalue = (statvalue-event
+ / statvalue-todo
+ / statvalue-jour)
+
+ statvalue-event = "TENTATIVE" ;Indicates event is tentative.
+ / "CONFIRMED" ;Indicates event is definite.
+ / "CANCELLED" ;Indicates event was cancelled.
+ ;Status values for a "VEVENT"
+
+ statvalue-todo = "NEEDS-ACTION" ;Indicates to-do needs action.
+ / "COMPLETED" ;Indicates to-do completed.
+ / "IN-PROCESS" ;Indicates to-do in process of.
+ / "CANCELLED" ;Indicates to-do was cancelled.
+ ;Status values for "VTODO".
+
+
+
+
+Desruisseaux Standards Track [Page 92]
+
+RFC 5545 iCalendar September 2009
+
+
+ statvalue-jour = "DRAFT" ;Indicates journal is draft.
+ / "FINAL" ;Indicates journal is final.
+ / "CANCELLED" ;Indicates journal is removed.
+ ;Status values for "VJOURNAL".
+
+ Example: The following is an example of this property for a "VEVENT"
+ calendar component:
+
+ STATUS:TENTATIVE
+
+ The following is an example of this property for a "VTODO"
+ calendar component:
+
+ STATUS:NEEDS-ACTION
+
+ The following is an example of this property for a "VJOURNAL"
+ calendar component:
+
+ STATUS:DRAFT
+
+3.8.1.12. Summary
+
+ Property Name: SUMMARY
+
+ Purpose: This property defines a short summary or subject for the
+ calendar component.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, alternate text
+ representation, and language property parameters can be specified
+ on this property.
+
+ Conformance: The property can be specified in "VEVENT", "VTODO",
+ "VJOURNAL", or "VALARM" calendar components.
+
+ Description: This property is used in the "VEVENT", "VTODO", and
+ "VJOURNAL" calendar components to capture a short, one-line
+ summary about the activity or journal entry.
+
+ This property is used in the "VALARM" calendar component to
+ capture the subject of an EMAIL category of alarm.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 93]
+
+RFC 5545 iCalendar September 2009
+
+
+ summary = "SUMMARY" summparam ":" text CRLF
+
+ summparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" altrepparam) / (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following is an example of this property:
+
+ SUMMARY:Department Party
+
+3.8.2. Date and Time Component Properties
+
+ The following properties specify date and time related information in
+ calendar components.
+
+3.8.2.1. Date-Time Completed
+
+ Property Name: COMPLETED
+
+ Purpose: This property defines the date and time that a to-do was
+ actually completed.
+
+ Value Type: DATE-TIME
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: The property can be specified in a "VTODO" calendar
+ component. The value MUST be specified as a date with UTC time.
+
+ Description: This property defines the date and time that a to-do
+ was actually completed.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 94]
+
+RFC 5545 iCalendar September 2009
+
+
+ completed = "COMPLETED" compparam ":" date-time CRLF
+
+ compparam = *(";" other-param)
+
+ Example: The following is an example of this property:
+
+ COMPLETED:19960401T150000Z
+
+3.8.2.2. Date-Time End
+
+ Property Name: DTEND
+
+ Purpose: This property specifies the date and time that a calendar
+ component ends.
+
+ Value Type: The default value type is DATE-TIME. The value type can
+ be set to a DATE value type.
+
+ Property Parameters: IANA, non-standard, value data type, and time
+ zone identifier property parameters can be specified on this
+ property.
+
+ Conformance: This property can be specified in "VEVENT" or
+ "VFREEBUSY" calendar components.
+
+ Description: Within the "VEVENT" calendar component, this property
+ defines the date and time by which the event ends. The value type
+ of this property MUST be the same as the "DTSTART" property, and
+ its value MUST be later in time than the value of the "DTSTART"
+ property. Furthermore, this property MUST be specified as a date
+ with local time if and only if the "DTSTART" property is also
+ specified as a date with local time.
+
+ Within the "VFREEBUSY" calendar component, this property defines
+ the end date and time for the free or busy time information. The
+ time MUST be specified in the UTC time format. The value MUST be
+ later in time than the value of the "DTSTART" property.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 95]
+
+RFC 5545 iCalendar September 2009
+
+
+ dtend = "DTEND" dtendparam ":" dtendval CRLF
+
+ dtendparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" "VALUE" "=" ("DATE-TIME" / "DATE")) /
+ (";" tzidparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ dtendval = date-time / date
+ ;Value MUST match value type
+
+ Example: The following is an example of this property:
+
+ DTEND:19960401T150000Z
+
+ DTEND;VALUE=DATE:19980704
+
+3.8.2.3. Date-Time Due
+
+ Property Name: DUE
+
+ Purpose: This property defines the date and time that a to-do is
+ expected to be completed.
+
+ Value Type: The default value type is DATE-TIME. The value type can
+ be set to a DATE value type.
+
+ Property Parameters: IANA, non-standard, value data type, and time
+ zone identifier property parameters can be specified on this
+ property.
+
+ Conformance: The property can be specified once in a "VTODO"
+ calendar component.
+
+ Description: This property defines the date and time before which a
+ to-do is expected to be completed. For cases where this property
+ is specified in a "VTODO" calendar component that also specifies a
+ "DTSTART" property, the value type of this property MUST be the
+ same as the "DTSTART" property, and the value of this property
+
+
+
+Desruisseaux Standards Track [Page 96]
+
+RFC 5545 iCalendar September 2009
+
+
+ MUST be later in time than the value of the "DTSTART" property.
+ Furthermore, this property MUST be specified as a date with local
+ time if and only if the "DTSTART" property is also specified as a
+ date with local time.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ due = "DUE" dueparam ":" dueval CRLF
+
+ dueparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" "VALUE" "=" ("DATE-TIME" / "DATE")) /
+ (";" tzidparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ dueval = date-time / date
+ ;Value MUST match value type
+
+ Example: The following is an example of this property:
+
+ DUE:19980430T000000Z
+
+3.8.2.4. Date-Time Start
+
+ Property Name: DTSTART
+
+ Purpose: This property specifies when the calendar component begins.
+
+ Value Type: The default value type is DATE-TIME. The time value
+ MUST be one of the forms defined for the DATE-TIME value type.
+ The value type can be set to a DATE value type.
+
+ Property Parameters: IANA, non-standard, value data type, and time
+ zone identifier property parameters can be specified on this
+ property.
+
+ Conformance: This property can be specified once in the "VEVENT",
+ "VTODO", or "VFREEBUSY" calendar components as well as in the
+
+
+
+Desruisseaux Standards Track [Page 97]
+
+RFC 5545 iCalendar September 2009
+
+
+ "STANDARD" and "DAYLIGHT" sub-components. This property is
+ REQUIRED in all types of recurring calendar components that
+ specify the "RRULE" property. This property is also REQUIRED in
+ "VEVENT" calendar components contained in iCalendar objects that
+ don't specify the "METHOD" property.
+
+ Description: Within the "VEVENT" calendar component, this property
+ defines the start date and time for the event.
+
+ Within the "VFREEBUSY" calendar component, this property defines
+ the start date and time for the free or busy time information.
+ The time MUST be specified in UTC time.
+
+ Within the "STANDARD" and "DAYLIGHT" sub-components, this property
+ defines the effective start date and time for a time zone
+ specification. This property is REQUIRED within each "STANDARD"
+ and "DAYLIGHT" sub-components included in "VTIMEZONE" calendar
+ components and MUST be specified as a date with local time without
+ the "TZID" property parameter.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ dtstart = "DTSTART" dtstparam ":" dtstval CRLF
+
+ dtstparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" "VALUE" "=" ("DATE-TIME" / "DATE")) /
+ (";" tzidparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ dtstval = date-time / date
+ ;Value MUST match value type
+
+ Example: The following is an example of this property:
+
+ DTSTART:19980118T073000Z
+
+
+
+
+
+Desruisseaux Standards Track [Page 98]
+
+RFC 5545 iCalendar September 2009
+
+
+3.8.2.5. Duration
+
+ Property Name: DURATION
+
+ Purpose: This property specifies a positive duration of time.
+
+ Value Type: DURATION
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified in "VEVENT", "VTODO", or
+ "VALARM" calendar components.
+
+ Description: In a "VEVENT" calendar component the property may be
+ used to specify a duration of the event, instead of an explicit
+ end DATE-TIME. In a "VTODO" calendar component the property may
+ be used to specify a duration for the to-do, instead of an
+ explicit due DATE-TIME. In a "VALARM" calendar component the
+ property may be used to specify the delay period prior to
+ repeating an alarm. When the "DURATION" property relates to a
+ "DTSTART" property that is specified as a DATE value, then the
+ "DURATION" property MUST be specified as a "dur-day" or "dur-week"
+ value.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ duration = "DURATION" durparam ":" dur-value CRLF
+ ;consisting of a positive duration of time.
+
+ durparam = *(";" other-param)
+
+ Example: The following is an example of this property that specifies
+ an interval of time of one hour and zero minutes and zero seconds:
+
+ DURATION:PT1H0M0S
+
+ The following is an example of this property that specifies an
+ interval of time of 15 minutes.
+
+ DURATION:PT15M
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 99]
+
+RFC 5545 iCalendar September 2009
+
+
+3.8.2.6. Free/Busy Time
+
+ Property Name: FREEBUSY
+
+ Purpose: This property defines one or more free or busy time
+ intervals.
+
+ Value Type: PERIOD
+
+ Property Parameters: IANA, non-standard, and free/busy time type
+ property parameters can be specified on this property.
+
+ Conformance: The property can be specified in a "VFREEBUSY" calendar
+ component.
+
+ Description: These time periods can be specified as either a start
+ and end DATE-TIME or a start DATE-TIME and DURATION. The date and
+ time MUST be a UTC time format.
+
+ "FREEBUSY" properties within the "VFREEBUSY" calendar component
+ SHOULD be sorted in ascending order, based on start time and then
+ end time, with the earliest periods first.
+
+ The "FREEBUSY" property can specify more than one value, separated
+ by the COMMA character. In such cases, the "FREEBUSY" property
+ values MUST all be of the same "FBTYPE" property parameter type
+ (e.g., all values of a particular "FBTYPE" listed together in a
+ single property).
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ freebusy = "FREEBUSY" fbparam ":" fbvalue CRLF
+
+ fbparam = *(
+ ;
+ ; The following is OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" fbtypeparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+
+
+
+Desruisseaux Standards Track [Page 100]
+
+RFC 5545 iCalendar September 2009
+
+
+ fbvalue = period *("," period)
+ ;Time value MUST be in the UTC time format.
+
+ Example: The following are some examples of this property:
+
+ FREEBUSY;FBTYPE=BUSY-UNAVAILABLE:19970308T160000Z/PT8H30M
+
+ FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H
+
+ FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H
+ ,19970308T230000Z/19970309T000000Z
+
+3.8.2.7. Time Transparency
+
+ Property Name: TRANSP
+
+ Purpose: This property defines whether or not an event is
+ transparent to busy time searches.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified once in a "VEVENT"
+ calendar component.
+
+ Description: Time Transparency is the characteristic of an event
+ that determines whether it appears to consume time on a calendar.
+ Events that consume actual time for the individual or resource
+ associated with the calendar SHOULD be recorded as OPAQUE,
+ allowing them to be detected by free/busy time searches. Other
+ events, which do not take up the individual's (or resource's) time
+ SHOULD be recorded as TRANSPARENT, making them invisible to free/
+ busy time searches.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ transp = "TRANSP" transparam ":" transvalue CRLF
+
+ transparam = *(";" other-param)
+
+ transvalue = "OPAQUE"
+ ;Blocks or opaque on busy time searches.
+ / "TRANSPARENT"
+ ;Transparent on busy time searches.
+ ;Default value is OPAQUE
+
+
+
+Desruisseaux Standards Track [Page 101]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example: The following is an example of this property for an event
+ that is transparent or does not block on free/busy time searches:
+
+ TRANSP:TRANSPARENT
+
+ The following is an example of this property for an event that is
+ opaque or blocks on free/busy time searches:
+
+ TRANSP:OPAQUE
+
+3.8.3. Time Zone Component Properties
+
+ The following properties specify time zone information in calendar
+ components.
+
+3.8.3.1. Time Zone Identifier
+
+ Property Name: TZID
+
+ Purpose: This property specifies the text value that uniquely
+ identifies the "VTIMEZONE" calendar component in the scope of an
+ iCalendar object.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property MUST be specified in a "VTIMEZONE"
+ calendar component.
+
+ Description: This is the label by which a time zone calendar
+ component is referenced by any iCalendar properties whose value
+ type is either DATE-TIME or TIME and not intended to specify a UTC
+ or a "floating" time. The presence of the SOLIDUS character as a
+ prefix, indicates that this "TZID" represents an unique ID in a
+ globally defined time zone registry (when such registry is
+ defined).
+
+ Note: This document does not define a naming convention for
+ time zone identifiers. Implementers may want to use the naming
+ conventions defined in existing time zone specifications such
+ as the public-domain TZ database [TZDB]. The specification of
+ globally unique time zone identifiers is not addressed by this
+ document and is left for future study.
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 102]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ tzid = "TZID" tzidpropparam ":" [tzidprefix] text CRLF
+
+ tzidpropparam = *(";" other-param)
+
+ ;tzidprefix = "/"
+ ; Defined previously. Just listed here for reader convenience.
+
+ Example: The following are examples of non-globally unique time zone
+ identifiers:
+
+ TZID:America/New_York
+
+ TZID:America/Los_Angeles
+
+ The following is an example of a fictitious globally unique time
+ zone identifier:
+
+ TZID:/example.org/America/New_York
+
+3.8.3.2. Time Zone Name
+
+ Property Name: TZNAME
+
+ Purpose: This property specifies the customary designation for a
+ time zone description.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, and language property
+ parameters can be specified on this property.
+
+ Conformance: This property can be specified in "STANDARD" and
+ "DAYLIGHT" sub-components.
+
+ Description: This property specifies a customary name that can be
+ used when displaying dates that occur during the observance
+ defined by the time zone sub-component.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 103]
+
+RFC 5545 iCalendar September 2009
+
+
+ tzname = "TZNAME" tznparam ":" text CRLF
+
+ tznparam = *(
+ ;
+ ; The following is OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following are examples of this property:
+
+ TZNAME:EST
+
+ TZNAME;LANGUAGE=fr-CA:HNE
+
+3.8.3.3. Time Zone Offset From
+
+ Property Name: TZOFFSETFROM
+
+ Purpose: This property specifies the offset that is in use prior to
+ this time zone observance.
+
+ Value Type: UTC-OFFSET
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property MUST be specified in "STANDARD" and
+ "DAYLIGHT" sub-components.
+
+ Description: This property specifies the offset that is in use prior
+ to this time observance. It is used to calculate the absolute
+ time at which the transition to a given observance takes place.
+ This property MUST only be specified in a "VTIMEZONE" calendar
+ component. A "VTIMEZONE" calendar component MUST include this
+ property. The property value is a signed numeric indicating the
+ number of hours and possibly minutes from UTC. Positive numbers
+ represent time zones east of the prime meridian, or ahead of UTC.
+ Negative numbers represent time zones west of the prime meridian,
+ or behind UTC.
+
+
+
+
+Desruisseaux Standards Track [Page 104]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ tzoffsetfrom = "TZOFFSETFROM" frmparam ":" utc-offset
+ CRLF
+
+ frmparam = *(";" other-param)
+
+ Example: The following are examples of this property:
+
+ TZOFFSETFROM:-0500
+
+ TZOFFSETFROM:+1345
+
+3.8.3.4. Time Zone Offset To
+
+ Property Name: TZOFFSETTO
+
+ Purpose: This property specifies the offset that is in use in this
+ time zone observance.
+
+ Value Type: UTC-OFFSET
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property MUST be specified in "STANDARD" and
+ "DAYLIGHT" sub-components.
+
+ Description: This property specifies the offset that is in use in
+ this time zone observance. It is used to calculate the absolute
+ time for the new observance. The property value is a signed
+ numeric indicating the number of hours and possibly minutes from
+ UTC. Positive numbers represent time zones east of the prime
+ meridian, or ahead of UTC. Negative numbers represent time zones
+ west of the prime meridian, or behind UTC.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ tzoffsetto = "TZOFFSETTO" toparam ":" utc-offset CRLF
+
+ toparam = *(";" other-param)
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 105]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example: The following are examples of this property:
+
+ TZOFFSETTO:-0400
+
+ TZOFFSETTO:+1245
+
+3.8.3.5. Time Zone URL
+
+ Property Name: TZURL
+
+ Purpose: This property provides a means for a "VTIMEZONE" component
+ to point to a network location that can be used to retrieve an up-
+ to-date version of itself.
+
+ Value Type: URI
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified in a "VTIMEZONE"
+ calendar component.
+
+ Description: This property provides a means for a "VTIMEZONE"
+ component to point to a network location that can be used to
+ retrieve an up-to-date version of itself. This provides a hook to
+ handle changes government bodies impose upon time zone
+ definitions. Retrieval of this resource results in an iCalendar
+ object containing a single "VTIMEZONE" component and a "METHOD"
+ property set to PUBLISH.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ tzurl = "TZURL" tzurlparam ":" uri CRLF
+
+ tzurlparam = *(";" other-param)
+
+ Example: The following is an example of this property:
+
+ TZURL:http://timezones.example.org/tz/America-Los_Angeles.ics
+
+3.8.4. Relationship Component Properties
+
+ The following properties specify relationship information in calendar
+ components.
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 106]
+
+RFC 5545 iCalendar September 2009
+
+
+3.8.4.1. Attendee
+
+ Property Name: ATTENDEE
+
+ Purpose: This property defines an "Attendee" within a calendar
+ component.
+
+ Value Type: CAL-ADDRESS
+
+ Property Parameters: IANA, non-standard, language, calendar user
+ type, group or list membership, participation role, participation
+ status, RSVP expectation, delegatee, delegator, sent by, common
+ name, or directory entry reference property parameters can be
+ specified on this property.
+
+ Conformance: This property MUST be specified in an iCalendar object
+ that specifies a group-scheduled calendar entity. This property
+ MUST NOT be specified in an iCalendar object when publishing the
+ calendar information (e.g., NOT in an iCalendar object that
+ specifies the publication of a calendar user's busy time, event,
+ to-do, or journal). This property is not specified in an
+ iCalendar object that specifies only a time zone definition or
+ that defines calendar components that are not group-scheduled
+ components, but are components only on a single user's calendar.
+
+ Description: This property MUST only be specified within calendar
+ components to specify participants, non-participants, and the
+ chair of a group-scheduled calendar entity. The property is
+ specified within an "EMAIL" category of the "VALARM" calendar
+ component to specify an email address that is to receive the email
+ type of iCalendar alarm.
+
+ The property parameter "CN" is for the common or displayable name
+ associated with the calendar address; "ROLE", for the intended
+ role that the attendee will have in the calendar component;
+ "PARTSTAT", for the status of the attendee's participation;
+ "RSVP", for indicating whether the favor of a reply is requested;
+ "CUTYPE", to indicate the type of calendar user; "MEMBER", to
+ indicate the groups that the attendee belongs to; "DELEGATED-TO",
+ to indicate the calendar users that the original request was
+ delegated to; and "DELEGATED-FROM", to indicate whom the request
+ was delegated from; "SENT-BY", to indicate whom is acting on
+ behalf of the "ATTENDEE"; and "DIR", to indicate the URI that
+ points to the directory information corresponding to the attendee.
+ These property parameters can be specified on an "ATTENDEE"
+ property in either a "VEVENT", "VTODO", or "VJOURNAL" calendar
+ component. They MUST NOT be specified in an "ATTENDEE" property
+ in a "VFREEBUSY" or "VALARM" calendar component. If the
+
+
+
+Desruisseaux Standards Track [Page 107]
+
+RFC 5545 iCalendar September 2009
+
+
+ "LANGUAGE" property parameter is specified, the identified
+ language applies to the "CN" parameter.
+
+ A recipient delegated a request MUST inherit the "RSVP" and "ROLE"
+ values from the attendee that delegated the request to them.
+
+ Multiple attendees can be specified by including multiple
+ "ATTENDEE" properties within the calendar component.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ attendee = "ATTENDEE" attparam ":" cal-address CRLF
+
+ attparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" cutypeparam) / (";" memberparam) /
+ (";" roleparam) / (";" partstatparam) /
+ (";" rsvpparam) / (";" deltoparam) /
+ (";" delfromparam) / (";" sentbyparam) /
+ (";" cnparam) / (";" dirparam) /
+ (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following are examples of this property's use for a
+ to-do:
+
+ ATTENDEE;MEMBER="mailto:DEV-GROUP@example.com":
+ mailto:joecool@example.com
+ ATTENDEE;DELEGATED-FROM="mailto:immud@example.com":
+ mailto:ildoit@example.com
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 108]
+
+RFC 5545 iCalendar September 2009
+
+
+ The following is an example of this property used for specifying
+ multiple attendees to an event:
+
+ ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE;CN=Henry
+ Cabot:mailto:hcabot@example.com
+ ATTENDEE;ROLE=REQ-PARTICIPANT;DELEGATED-FROM="mailto:bob@
+ example.com";PARTSTAT=ACCEPTED;CN=Jane Doe:mailto:jdoe@
+ example.com
+
+ The following is an example of this property with a URI to the
+ directory information associated with the attendee:
+
+ ATTENDEE;CN=John Smith;DIR="ldap://example.com:6666/o=ABC%
+ 20Industries,c=US???(cn=Jim%20Dolittle)":mailto:jimdo@
+ example.com
+
+ The following is an example of this property with "delegatee" and
+ "delegator" information for an event:
+
+ ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE;DELEGATED-FROM=
+ "mailto:iamboss@example.com";CN=Henry Cabot:mailto:hcabot@
+ example.com
+ ATTENDEE;ROLE=NON-PARTICIPANT;PARTSTAT=DELEGATED;DELEGATED-TO=
+ "mailto:hcabot@example.com";CN=The Big Cheese:mailto:iamboss
+ @example.com
+ ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;CN=Jane Doe
+ :mailto:jdoe@example.com
+
+ Example: The following is an example of this property's use when
+ another calendar user is acting on behalf of the "Attendee":
+
+ ATTENDEE;SENT-BY=mailto:jan_doe@example.com;CN=John Smith:
+ mailto:jsmith@example.com
+
+3.8.4.2. Contact
+
+ Property Name: CONTACT
+
+ Purpose: This property is used to represent contact information or
+ alternately a reference to contact information associated with the
+ calendar component.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, alternate text
+ representation, and language property parameters can be specified
+ on this property.
+
+
+
+
+Desruisseaux Standards Track [Page 109]
+
+RFC 5545 iCalendar September 2009
+
+
+ Conformance: This property can be specified in a "VEVENT", "VTODO",
+ "VJOURNAL", or "VFREEBUSY" calendar component.
+
+ Description: The property value consists of textual contact
+ information. An alternative representation for the property value
+ can also be specified that refers to a URI pointing to an
+ alternate form, such as a vCard [RFC2426], for the contact
+ information.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ contact = "CONTACT" contparam ":" text CRLF
+
+ contparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" altrepparam) / (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following is an example of this property referencing
+ textual contact information:
+
+ CONTACT:Jim Dolittle\, ABC Industries\, +1-919-555-1234
+
+ The following is an example of this property with an alternate
+ representation of an LDAP URI to a directory entry containing the
+ contact information:
+
+ CONTACT;ALTREP="ldap://example.com:6666/o=ABC%20Industries\,
+ c=US???(cn=Jim%20Dolittle)":Jim Dolittle\, ABC Industries\,
+ +1-919-555-1234
+
+ The following is an example of this property with an alternate
+ representation of a MIME body part containing the contact
+ information, such as a vCard [RFC2426] embedded in a text/
+ directory media type [RFC2425]:
+
+ CONTACT;ALTREP="CID:part3.msg970930T083000SILVER@example.com":
+ Jim Dolittle\, ABC Industries\, +1-919-555-1234
+
+
+
+Desruisseaux Standards Track [Page 110]
+
+RFC 5545 iCalendar September 2009
+
+
+ The following is an example of this property referencing a network
+ resource, such as a vCard [RFC2426] object containing the contact
+ information:
+
+ CONTACT;ALTREP="http://example.com/pdi/jdoe.vcf":Jim
+ Dolittle\, ABC Industries\, +1-919-555-1234
+
+3.8.4.3. Organizer
+
+ Property Name: ORGANIZER
+
+ Purpose: This property defines the organizer for a calendar
+ component.
+
+ Value Type: CAL-ADDRESS
+
+ Property Parameters: IANA, non-standard, language, common name,
+ directory entry reference, and sent-by property parameters can be
+ specified on this property.
+
+ Conformance: This property MUST be specified in an iCalendar object
+ that specifies a group-scheduled calendar entity. This property
+ MUST be specified in an iCalendar object that specifies the
+ publication of a calendar user's busy time. This property MUST
+ NOT be specified in an iCalendar object that specifies only a time
+ zone definition or that defines calendar components that are not
+ group-scheduled components, but are components only on a single
+ user's calendar.
+
+ Description: This property is specified within the "VEVENT",
+ "VTODO", and "VJOURNAL" calendar components to specify the
+ organizer of a group-scheduled calendar entity. The property is
+ specified within the "VFREEBUSY" calendar component to specify the
+ calendar user requesting the free or busy time. When publishing a
+ "VFREEBUSY" calendar component, the property is used to specify
+ the calendar that the published busy time came from.
+
+ The property has the property parameters "CN", for specifying the
+ common or display name associated with the "Organizer", "DIR", for
+ specifying a pointer to the directory information associated with
+ the "Organizer", "SENT-BY", for specifying another calendar user
+ that is acting on behalf of the "Organizer". The non-standard
+ parameters may also be specified on this property. If the
+ "LANGUAGE" property parameter is specified, the identified
+ language applies to the "CN" parameter value.
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 111]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ organizer = "ORGANIZER" orgparam ":"
+ cal-address CRLF
+
+ orgparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" cnparam) / (";" dirparam) / (";" sentbyparam) /
+ (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ Example: The following is an example of this property:
+
+ ORGANIZER;CN=John Smith:mailto:jsmith@example.com
+
+ The following is an example of this property with a pointer to the
+ directory information associated with the organizer:
+
+ ORGANIZER;CN=JohnSmith;DIR="ldap://example.com:6666/o=DC%20Ass
+ ociates,c=US???(cn=John%20Smith)":mailto:jsmith@example.com
+
+ The following is an example of this property used by another
+ calendar user who is acting on behalf of the organizer, with
+ responses intended to be sent back to the organizer, not the other
+ calendar user:
+
+ ORGANIZER;SENT-BY="mailto:jane_doe@example.com":
+ mailto:jsmith@example.com
+
+3.8.4.4. Recurrence ID
+
+ Property Name: RECURRENCE-ID
+
+ Purpose: This property is used in conjunction with the "UID" and
+ "SEQUENCE" properties to identify a specific instance of a
+ recurring "VEVENT", "VTODO", or "VJOURNAL" calendar component.
+ The property value is the original value of the "DTSTART" property
+ of the recurrence instance.
+
+
+
+Desruisseaux Standards Track [Page 112]
+
+RFC 5545 iCalendar September 2009
+
+
+ Value Type: The default value type is DATE-TIME. The value type can
+ be set to a DATE value type. This property MUST have the same
+ value type as the "DTSTART" property contained within the
+ recurring component. Furthermore, this property MUST be specified
+ as a date with local time if and only if the "DTSTART" property
+ contained within the recurring component is specified as a date
+ with local time.
+
+ Property Parameters: IANA, non-standard, value data type, time zone
+ identifier, and recurrence identifier range parameters can be
+ specified on this property.
+
+ Conformance: This property can be specified in an iCalendar object
+ containing a recurring calendar component.
+
+ Description: The full range of calendar components specified by a
+ recurrence set is referenced by referring to just the "UID"
+ property value corresponding to the calendar component. The
+ "RECURRENCE-ID" property allows the reference to an individual
+ instance within the recurrence set.
+
+ If the value of the "DTSTART" property is a DATE type value, then
+ the value MUST be the calendar date for the recurrence instance.
+
+ The DATE-TIME value is set to the time when the original
+ recurrence instance would occur; meaning that if the intent is to
+ change a Friday meeting to Thursday, the DATE-TIME is still set to
+ the original Friday meeting.
+
+ The "RECURRENCE-ID" property is used in conjunction with the "UID"
+ and "SEQUENCE" properties to identify a particular instance of a
+ recurring event, to-do, or journal. For a given pair of "UID" and
+ "SEQUENCE" property values, the "RECURRENCE-ID" value for a
+ recurrence instance is fixed.
+
+ The "RANGE" parameter is used to specify the effective range of
+ recurrence instances from the instance specified by the
+ "RECURRENCE-ID" property value. The value for the range parameter
+ can only be "THISANDFUTURE" to indicate a range defined by the
+ given recurrence instance and all subsequent instances.
+ Subsequent instances are determined by their "RECURRENCE-ID" value
+ and not their current scheduled start time. Subsequent instances
+ defined in separate components are not impacted by the given
+ recurrence instance. When the given recurrence instance is
+ rescheduled, all subsequent instances are also rescheduled by the
+ same time difference. For instance, if the given recurrence
+ instance is rescheduled to start 2 hours later, then all
+ subsequent instances are also rescheduled 2 hours later.
+
+
+
+Desruisseaux Standards Track [Page 113]
+
+RFC 5545 iCalendar September 2009
+
+
+ Similarly, if the duration of the given recurrence instance is
+ modified, then all subsequence instances are also modified to have
+ this same duration.
+
+ Note: The "RANGE" parameter may not be appropriate to
+ reschedule specific subsequent instances of complex recurring
+ calendar component. Assuming an unbounded recurring calendar
+ component scheduled to occur on Mondays and Wednesdays, the
+ "RANGE" parameter could not be used to reschedule only the
+ future Monday instances to occur on Tuesday instead. In such
+ cases, the calendar application could simply truncate the
+ unbounded recurring calendar component (i.e., with the "COUNT"
+ or "UNTIL" rule parts), and create two new unbounded recurring
+ calendar components for the future instances.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ recurid = "RECURRENCE-ID" ridparam ":" ridval CRLF
+
+ ridparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" "VALUE" "=" ("DATE-TIME" / "DATE")) /
+ (";" tzidparam) / (";" rangeparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ ridval = date-time / date
+ ;Value MUST match value type
+
+ Example: The following are examples of this property:
+
+ RECURRENCE-ID;VALUE=DATE:19960401
+
+ RECURRENCE-ID;RANGE=THISANDFUTURE:19960120T120000Z
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 114]
+
+RFC 5545 iCalendar September 2009
+
+
+3.8.4.5. Related To
+
+ Property Name: RELATED-TO
+
+ Purpose: This property is used to represent a relationship or
+ reference between one calendar component and another.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, and relationship type
+ property parameters can be specified on this property.
+
+ Conformance: This property can be specified in the "VEVENT",
+ "VTODO", and "VJOURNAL" calendar components.
+
+ Description: The property value consists of the persistent, globally
+ unique identifier of another calendar component. This value would
+ be represented in a calendar component by the "UID" property.
+
+ By default, the property value points to another calendar
+ component that has a PARENT relationship to the referencing
+ object. The "RELTYPE" property parameter is used to either
+ explicitly state the default PARENT relationship type to the
+ referenced calendar component or to override the default PARENT
+ relationship type and specify either a CHILD or SIBLING
+ relationship. The PARENT relationship indicates that the calendar
+ component is a subordinate of the referenced calendar component.
+ The CHILD relationship indicates that the calendar component is a
+ superior of the referenced calendar component. The SIBLING
+ relationship indicates that the calendar component is a peer of
+ the referenced calendar component.
+
+ Changes to a calendar component referenced by this property can
+ have an implicit impact on the related calendar component. For
+ example, if a group event changes its start or end date or time,
+ then the related, dependent events will need to have their start
+ and end dates changed in a corresponding way. Similarly, if a
+ PARENT calendar component is cancelled or deleted, then there is
+ an implied impact to the related CHILD calendar components. This
+ property is intended only to provide information on the
+ relationship of calendar components. It is up to the target
+ calendar system to maintain any property implications of this
+ relationship.
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 115]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ related = "RELATED-TO" relparam ":" text CRLF
+
+ relparam = *(
+ ;
+ ; The following is OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" reltypeparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ The following is an example of this property:
+
+ RELATED-TO:jsmith.part7.19960817T083000.xyzMail@example.com
+
+ RELATED-TO:19960401-080045-4000F192713-0052@example.com
+
+3.8.4.6. Uniform Resource Locator
+
+ Property Name: URL
+
+ Purpose: This property defines a Uniform Resource Locator (URL)
+ associated with the iCalendar object.
+
+ Value Type: URI
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified once in the "VEVENT",
+ "VTODO", "VJOURNAL", or "VFREEBUSY" calendar components.
+
+ Description: This property may be used in a calendar component to
+ convey a location where a more dynamic rendition of the calendar
+ information associated with the calendar component can be found.
+ This memo does not attempt to standardize the form of the URI, nor
+ the format of the resource pointed to by the property value. If
+ the URL property and Content-Location MIME header are both
+ specified, they MUST point to the same resource.
+
+
+
+
+Desruisseaux Standards Track [Page 116]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ url = "URL" urlparam ":" uri CRLF
+
+ urlparam = *(";" other-param)
+
+ Example: The following is an example of this property:
+
+ URL:http://example.com/pub/calendars/jsmith/mytime.ics
+
+3.8.4.7. Unique Identifier
+
+ Property Name: UID
+
+ Purpose: This property defines the persistent, globally unique
+ identifier for the calendar component.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: The property MUST be specified in the "VEVENT",
+ "VTODO", "VJOURNAL", or "VFREEBUSY" calendar components.
+
+ Description: The "UID" itself MUST be a globally unique identifier.
+ The generator of the identifier MUST guarantee that the identifier
+ is unique. There are several algorithms that can be used to
+ accomplish this. A good method to assure uniqueness is to put the
+ domain name or a domain literal IP address of the host on which
+ the identifier was created on the right-hand side of an "@", and
+ on the left-hand side, put a combination of the current calendar
+ date and time of day (i.e., formatted in as a DATE-TIME value)
+ along with some other currently unique (perhaps sequential)
+ identifier available on the system (for example, a process id
+ number). Using a DATE-TIME value on the left-hand side and a
+ domain name or domain literal on the right-hand side makes it
+ possible to guarantee uniqueness since no two hosts should be
+ using the same domain name or IP address at the same time. Though
+ other algorithms will work, it is RECOMMENDED that the right-hand
+ side contain some domain identifier (either of the host itself or
+ otherwise) such that the generator of the message identifier can
+ guarantee the uniqueness of the left-hand side within the scope of
+ that domain.
+
+ This is the method for correlating scheduling messages with the
+ referenced "VEVENT", "VTODO", or "VJOURNAL" calendar component.
+
+
+
+Desruisseaux Standards Track [Page 117]
+
+RFC 5545 iCalendar September 2009
+
+
+ The full range of calendar components specified by a recurrence
+ set is referenced by referring to just the "UID" property value
+ corresponding to the calendar component. The "RECURRENCE-ID"
+ property allows the reference to an individual instance within the
+ recurrence set.
+
+ This property is an important method for group-scheduling
+ applications to match requests with later replies, modifications,
+ or deletion requests. Calendaring and scheduling applications
+ MUST generate this property in "VEVENT", "VTODO", and "VJOURNAL"
+ calendar components to assure interoperability with other group-
+ scheduling applications. This identifier is created by the
+ calendar system that generates an iCalendar object.
+
+ Implementations MUST be able to receive and persist values of at
+ least 255 octets for this property, but they MUST NOT truncate
+ values in the middle of a UTF-8 multi-octet sequence.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ uid = "UID" uidparam ":" text CRLF
+
+ uidparam = *(";" other-param)
+
+ Example: The following is an example of this property:
+
+ UID:19960401T080045Z-4000F192713-0052@example.com
+
+3.8.5. Recurrence Component Properties
+
+ The following properties specify recurrence information in calendar
+ components.
+
+3.8.5.1. Exception Date-Times
+
+ Property Name: EXDATE
+
+ Purpose: This property defines the list of DATE-TIME exceptions for
+ recurring events, to-dos, journal entries, or time zone
+ definitions.
+
+ Value Type: The default value type for this property is DATE-TIME.
+ The value type can be set to DATE.
+
+ Property Parameters: IANA, non-standard, value data type, and time
+ zone identifier property parameters can be specified on this
+ property.
+
+
+
+Desruisseaux Standards Track [Page 118]
+
+RFC 5545 iCalendar September 2009
+
+
+ Conformance: This property can be specified in recurring "VEVENT",
+ "VTODO", and "VJOURNAL" calendar components as well as in the
+ "STANDARD" and "DAYLIGHT" sub-components of the "VTIMEZONE"
+ calendar component.
+
+ Description: The exception dates, if specified, are used in
+ computing the recurrence set. The recurrence set is the complete
+ set of recurrence instances for a calendar component. The
+ recurrence set is generated by considering the initial "DTSTART"
+ property along with the "RRULE", "RDATE", and "EXDATE" properties
+ contained within the recurring component. The "DTSTART" property
+ defines the first instance in the recurrence set. The "DTSTART"
+ property value SHOULD match the pattern of the recurrence rule, if
+ specified. The recurrence set generated with a "DTSTART" property
+ value that doesn't match the pattern of the rule is undefined.
+ The final recurrence set is generated by gathering all of the
+ start DATE-TIME values generated by any of the specified "RRULE"
+ and "RDATE" properties, and then excluding any start DATE-TIME
+ values specified by "EXDATE" properties. This implies that start
+ DATE-TIME values specified by "EXDATE" properties take precedence
+ over those specified by inclusion properties (i.e., "RDATE" and
+ "RRULE"). When duplicate instances are generated by the "RRULE"
+ and "RDATE" properties, only one recurrence is considered.
+ Duplicate instances are ignored.
+
+ The "EXDATE" property can be used to exclude the value specified
+ in "DTSTART". However, in such cases, the original "DTSTART" date
+ MUST still be maintained by the calendaring and scheduling system
+ because the original "DTSTART" value has inherent usage
+ dependencies by other properties such as the "RECURRENCE-ID".
+
+ Format Definition: This property is defined by the following
+ notation:
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 119]
+
+RFC 5545 iCalendar September 2009
+
+
+ exdate = "EXDATE" exdtparam ":" exdtval *("," exdtval) CRLF
+
+ exdtparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" "VALUE" "=" ("DATE-TIME" / "DATE")) /
+ ;
+ (";" tzidparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ exdtval = date-time / date
+ ;Value MUST match value type
+
+ Example: The following is an example of this property:
+
+ EXDATE:19960402T010000Z,19960403T010000Z,19960404T010000Z
+
+3.8.5.2. Recurrence Date-Times
+
+ Property Name: RDATE
+
+ Purpose: This property defines the list of DATE-TIME values for
+ recurring events, to-dos, journal entries, or time zone
+ definitions.
+
+ Value Type: The default value type for this property is DATE-TIME.
+ The value type can be set to DATE or PERIOD.
+
+ Property Parameters: IANA, non-standard, value data type, and time
+ zone identifier property parameters can be specified on this
+ property.
+
+ Conformance: This property can be specified in recurring "VEVENT",
+ "VTODO", and "VJOURNAL" calendar components as well as in the
+ "STANDARD" and "DAYLIGHT" sub-components of the "VTIMEZONE"
+ calendar component.
+
+ Description: This property can appear along with the "RRULE"
+ property to define an aggregate set of repeating occurrences.
+ When they both appear in a recurring component, the recurrence
+
+
+
+Desruisseaux Standards Track [Page 120]
+
+RFC 5545 iCalendar September 2009
+
+
+ instances are defined by the union of occurrences defined by both
+ the "RDATE" and "RRULE".
+
+ The recurrence dates, if specified, are used in computing the
+ recurrence set. The recurrence set is the complete set of
+ recurrence instances for a calendar component. The recurrence set
+ is generated by considering the initial "DTSTART" property along
+ with the "RRULE", "RDATE", and "EXDATE" properties contained
+ within the recurring component. The "DTSTART" property defines
+ the first instance in the recurrence set. The "DTSTART" property
+ value SHOULD match the pattern of the recurrence rule, if
+ specified. The recurrence set generated with a "DTSTART" property
+ value that doesn't match the pattern of the rule is undefined.
+ The final recurrence set is generated by gathering all of the
+ start DATE-TIME values generated by any of the specified "RRULE"
+ and "RDATE" properties, and then excluding any start DATE-TIME
+ values specified by "EXDATE" properties. This implies that start
+ DATE-TIME values specified by "EXDATE" properties take precedence
+ over those specified by inclusion properties (i.e., "RDATE" and
+ "RRULE"). Where duplicate instances are generated by the "RRULE"
+ and "RDATE" properties, only one recurrence is considered.
+ Duplicate instances are ignored.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ rdate = "RDATE" rdtparam ":" rdtval *("," rdtval) CRLF
+
+ rdtparam = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" "VALUE" "=" ("DATE-TIME" / "DATE" / "PERIOD")) /
+ (";" tzidparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ rdtval = date-time / date / period
+ ;Value MUST match value type
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 121]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example: The following are examples of this property:
+
+ RDATE:19970714T123000Z
+ RDATE;TZID=America/New_York:19970714T083000
+
+ RDATE;VALUE=PERIOD:19960403T020000Z/19960403T040000Z,
+ 19960404T010000Z/PT3H
+
+ RDATE;VALUE=DATE:19970101,19970120,19970217,19970421
+ 19970526,19970704,19970901,19971014,19971128,19971129,19971225
+
+3.8.5.3. Recurrence Rule
+
+ Property Name: RRULE
+
+ Purpose: This property defines a rule or repeating pattern for
+ recurring events, to-dos, journal entries, or time zone
+ definitions.
+
+ Value Type: RECUR
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified in recurring "VEVENT",
+ "VTODO", and "VJOURNAL" calendar components as well as in the
+ "STANDARD" and "DAYLIGHT" sub-components of the "VTIMEZONE"
+ calendar component, but it SHOULD NOT be specified more than once.
+ The recurrence set generated with multiple "RRULE" properties is
+ undefined.
+
+ Description: The recurrence rule, if specified, is used in computing
+ the recurrence set. The recurrence set is the complete set of
+ recurrence instances for a calendar component. The recurrence set
+ is generated by considering the initial "DTSTART" property along
+ with the "RRULE", "RDATE", and "EXDATE" properties contained
+ within the recurring component. The "DTSTART" property defines
+ the first instance in the recurrence set. The "DTSTART" property
+ value SHOULD be synchronized with the recurrence rule, if
+ specified. The recurrence set generated with a "DTSTART" property
+ value not synchronized with the recurrence rule is undefined. The
+ final recurrence set is generated by gathering all of the start
+ DATE-TIME values generated by any of the specified "RRULE" and
+ "RDATE" properties, and then excluding any start DATE-TIME values
+ specified by "EXDATE" properties. This implies that start DATE-
+ TIME values specified by "EXDATE" properties take precedence over
+ those specified by inclusion properties (i.e., "RDATE" and
+ "RRULE"). Where duplicate instances are generated by the "RRULE"
+
+
+
+Desruisseaux Standards Track [Page 122]
+
+RFC 5545 iCalendar September 2009
+
+
+ and "RDATE" properties, only one recurrence is considered.
+ Duplicate instances are ignored.
+
+ The "DTSTART" property specified within the iCalendar object
+ defines the first instance of the recurrence. In most cases, a
+ "DTSTART" property of DATE-TIME value type used with a recurrence
+ rule, should be specified as a date with local time and time zone
+ reference to make sure all the recurrence instances start at the
+ same local time regardless of time zone changes.
+
+ If the duration of the recurring component is specified with the
+ "DTEND" or "DUE" property, then the same exact duration will apply
+ to all the members of the generated recurrence set. Else, if the
+ duration of the recurring component is specified with the
+ "DURATION" property, then the same nominal duration will apply to
+ all the members of the generated recurrence set and the exact
+ duration of each recurrence instance will depend on its specific
+ start time. For example, recurrence instances of a nominal
+ duration of one day will have an exact duration of more or less
+ than 24 hours on a day where a time zone shift occurs. The
+ duration of a specific recurrence may be modified in an exception
+ component or simply by using an "RDATE" property of PERIOD value
+ type.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ rrule = "RRULE" rrulparam ":" recur CRLF
+
+ rrulparam = *(";" other-param)
+
+ Example: All examples assume the Eastern United States time zone.
+
+ Daily for 10 occurrences:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=DAILY;COUNT=10
+
+ ==> (1997 9:00 AM EDT) September 2-11
+
+ Daily until December 24, 1997:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=DAILY;UNTIL=19971224T000000Z
+
+ ==> (1997 9:00 AM EDT) September 2-30;October 1-25
+ (1997 9:00 AM EST) October 26-31;November 1-30;December 1-23
+
+
+
+
+Desruisseaux Standards Track [Page 123]
+
+RFC 5545 iCalendar September 2009
+
+
+ Every other day - forever:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=DAILY;INTERVAL=2
+
+ ==> (1997 9:00 AM EDT) September 2,4,6,8...24,26,28,30;
+ October 2,4,6...20,22,24
+ (1997 9:00 AM EST) October 26,28,30;
+ November 1,3,5,7...25,27,29;
+ December 1,3,...
+
+ Every 10 days, 5 occurrences:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=DAILY;INTERVAL=10;COUNT=5
+
+ ==> (1997 9:00 AM EDT) September 2,12,22;
+ October 2,12
+
+ Every day in January, for 3 years:
+
+ DTSTART;TZID=America/New_York:19980101T090000
+
+ RRULE:FREQ=YEARLY;UNTIL=20000131T140000Z;
+ BYMONTH=1;BYDAY=SU,MO,TU,WE,TH,FR,SA
+ or
+ RRULE:FREQ=DAILY;UNTIL=20000131T140000Z;BYMONTH=1
+
+ ==> (1998 9:00 AM EST)January 1-31
+ (1999 9:00 AM EST)January 1-31
+ (2000 9:00 AM EST)January 1-31
+
+ Weekly for 10 occurrences:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=WEEKLY;COUNT=10
+
+ ==> (1997 9:00 AM EDT) September 2,9,16,23,30;October 7,14,21
+ (1997 9:00 AM EST) October 28;November 4
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 124]
+
+RFC 5545 iCalendar September 2009
+
+
+ Weekly until December 24, 1997:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=WEEKLY;UNTIL=19971224T000000Z
+
+ ==> (1997 9:00 AM EDT) September 2,9,16,23,30;
+ October 7,14,21
+ (1997 9:00 AM EST) October 28;
+ November 4,11,18,25;
+ December 2,9,16,23
+
+ Every other week - forever:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=WEEKLY;INTERVAL=2;WKST=SU
+
+ ==> (1997 9:00 AM EDT) September 2,16,30;
+ October 14
+ (1997 9:00 AM EST) October 28;
+ November 11,25;
+ December 9,23
+ (1998 9:00 AM EST) January 6,20;
+ February 3, 17
+ ...
+
+ Weekly on Tuesday and Thursday for five weeks:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=WEEKLY;UNTIL=19971007T000000Z;WKST=SU;BYDAY=TU,TH
+
+ or
+
+ RRULE:FREQ=WEEKLY;COUNT=10;WKST=SU;BYDAY=TU,TH
+
+ ==> (1997 9:00 AM EDT) September 2,4,9,11,16,18,23,25,30;
+ October 2
+
+ Every other week on Monday, Wednesday, and Friday until December
+ 24, 1997, starting on Monday, September 1, 1997:
+
+ DTSTART;TZID=America/New_York:19970901T090000
+ RRULE:FREQ=WEEKLY;INTERVAL=2;UNTIL=19971224T000000Z;WKST=SU;
+ BYDAY=MO,WE,FR
+
+ ==> (1997 9:00 AM EDT) September 1,3,5,15,17,19,29;
+ October 1,3,13,15,17
+ (1997 9:00 AM EST) October 27,29,31;
+ November 10,12,14,24,26,28;
+
+
+
+Desruisseaux Standards Track [Page 125]
+
+RFC 5545 iCalendar September 2009
+
+
+ December 8,10,12,22
+
+ Every other week on Tuesday and Thursday, for 8 occurrences:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=8;WKST=SU;BYDAY=TU,TH
+
+ ==> (1997 9:00 AM EDT) September 2,4,16,18,30;
+ October 2,14,16
+
+ Monthly on the first Friday for 10 occurrences:
+
+ DTSTART;TZID=America/New_York:19970905T090000
+ RRULE:FREQ=MONTHLY;COUNT=10;BYDAY=1FR
+
+ ==> (1997 9:00 AM EDT) September 5;October 3
+ (1997 9:00 AM EST) November 7;December 5
+ (1998 9:00 AM EST) January 2;February 6;March 6;April 3
+ (1998 9:00 AM EDT) May 1;June 5
+
+ Monthly on the first Friday until December 24, 1997:
+
+ DTSTART;TZID=America/New_York:19970905T090000
+ RRULE:FREQ=MONTHLY;UNTIL=19971224T000000Z;BYDAY=1FR
+
+ ==> (1997 9:00 AM EDT) September 5; October 3
+ (1997 9:00 AM EST) November 7; December 5
+
+ Every other month on the first and last Sunday of the month for 10
+ occurrences:
+
+ DTSTART;TZID=America/New_York:19970907T090000
+ RRULE:FREQ=MONTHLY;INTERVAL=2;COUNT=10;BYDAY=1SU,-1SU
+
+ ==> (1997 9:00 AM EDT) September 7,28
+ (1997 9:00 AM EST) November 2,30
+ (1998 9:00 AM EST) January 4,25;March 1,29
+ (1998 9:00 AM EDT) May 3,31
+
+ Monthly on the second-to-last Monday of the month for 6 months:
+
+ DTSTART;TZID=America/New_York:19970922T090000
+ RRULE:FREQ=MONTHLY;COUNT=6;BYDAY=-2MO
+
+ ==> (1997 9:00 AM EDT) September 22;October 20
+ (1997 9:00 AM EST) November 17;December 22
+ (1998 9:00 AM EST) January 19;February 16
+
+
+
+
+Desruisseaux Standards Track [Page 126]
+
+RFC 5545 iCalendar September 2009
+
+
+ Monthly on the third-to-the-last day of the month, forever:
+
+ DTSTART;TZID=America/New_York:19970928T090000
+ RRULE:FREQ=MONTHLY;BYMONTHDAY=-3
+
+ ==> (1997 9:00 AM EDT) September 28
+ (1997 9:00 AM EST) October 29;November 28;December 29
+ (1998 9:00 AM EST) January 29;February 26
+ ...
+
+ Monthly on the 2nd and 15th of the month for 10 occurrences:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=2,15
+
+ ==> (1997 9:00 AM EDT) September 2,15;October 2,15
+ (1997 9:00 AM EST) November 2,15;December 2,15
+ (1998 9:00 AM EST) January 2,15
+
+ Monthly on the first and last day of the month for 10 occurrences:
+
+ DTSTART;TZID=America/New_York:19970930T090000
+ RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=1,-1
+
+ ==> (1997 9:00 AM EDT) September 30;October 1
+ (1997 9:00 AM EST) October 31;November 1,30;December 1,31
+ (1998 9:00 AM EST) January 1,31;February 1
+
+ Every 18 months on the 10th thru 15th of the month for 10
+ occurrences:
+
+ DTSTART;TZID=America/New_York:19970910T090000
+ RRULE:FREQ=MONTHLY;INTERVAL=18;COUNT=10;BYMONTHDAY=10,11,12,
+ 13,14,15
+
+ ==> (1997 9:00 AM EDT) September 10,11,12,13,14,15
+ (1999 9:00 AM EST) March 10,11,12,13
+
+ Every Tuesday, every other month:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=MONTHLY;INTERVAL=2;BYDAY=TU
+
+ ==> (1997 9:00 AM EDT) September 2,9,16,23,30
+ (1997 9:00 AM EST) November 4,11,18,25
+ (1998 9:00 AM EST) January 6,13,20,27;March 3,10,17,24,31
+ ...
+
+
+
+
+Desruisseaux Standards Track [Page 127]
+
+RFC 5545 iCalendar September 2009
+
+
+ Yearly in June and July for 10 occurrences:
+
+ DTSTART;TZID=America/New_York:19970610T090000
+ RRULE:FREQ=YEARLY;COUNT=10;BYMONTH=6,7
+
+ ==> (1997 9:00 AM EDT) June 10;July 10
+ (1998 9:00 AM EDT) June 10;July 10
+ (1999 9:00 AM EDT) June 10;July 10
+ (2000 9:00 AM EDT) June 10;July 10
+ (2001 9:00 AM EDT) June 10;July 10
+
+ Note: Since none of the BYDAY, BYMONTHDAY, or BYYEARDAY
+ components are specified, the day is gotten from "DTSTART".
+
+ Every other year on January, February, and March for 10
+ occurrences:
+
+ DTSTART;TZID=America/New_York:19970310T090000
+ RRULE:FREQ=YEARLY;INTERVAL=2;COUNT=10;BYMONTH=1,2,3
+
+ ==> (1997 9:00 AM EST) March 10
+ (1999 9:00 AM EST) January 10;February 10;March 10
+ (2001 9:00 AM EST) January 10;February 10;March 10
+ (2003 9:00 AM EST) January 10;February 10;March 10
+
+ Every third year on the 1st, 100th, and 200th day for 10
+ occurrences:
+
+ DTSTART;TZID=America/New_York:19970101T090000
+ RRULE:FREQ=YEARLY;INTERVAL=3;COUNT=10;BYYEARDAY=1,100,200
+
+ ==> (1997 9:00 AM EST) January 1
+ (1997 9:00 AM EDT) April 10;July 19
+ (2000 9:00 AM EST) January 1
+ (2000 9:00 AM EDT) April 9;July 18
+ (2003 9:00 AM EST) January 1
+ (2003 9:00 AM EDT) April 10;July 19
+ (2006 9:00 AM EST) January 1
+
+ Every 20th Monday of the year, forever:
+
+ DTSTART;TZID=America/New_York:19970519T090000
+ RRULE:FREQ=YEARLY;BYDAY=20MO
+
+ ==> (1997 9:00 AM EDT) May 19
+ (1998 9:00 AM EDT) May 18
+ (1999 9:00 AM EDT) May 17
+ ...
+
+
+
+Desruisseaux Standards Track [Page 128]
+
+RFC 5545 iCalendar September 2009
+
+
+ Monday of week number 20 (where the default start of the week is
+ Monday), forever:
+
+ DTSTART;TZID=America/New_York:19970512T090000
+ RRULE:FREQ=YEARLY;BYWEEKNO=20;BYDAY=MO
+
+ ==> (1997 9:00 AM EDT) May 12
+ (1998 9:00 AM EDT) May 11
+ (1999 9:00 AM EDT) May 17
+ ...
+
+ Every Thursday in March, forever:
+
+ DTSTART;TZID=America/New_York:19970313T090000
+ RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=TH
+
+ ==> (1997 9:00 AM EST) March 13,20,27
+ (1998 9:00 AM EST) March 5,12,19,26
+ (1999 9:00 AM EST) March 4,11,18,25
+ ...
+
+ Every Thursday, but only during June, July, and August, forever:
+
+ DTSTART;TZID=America/New_York:19970605T090000
+ RRULE:FREQ=YEARLY;BYDAY=TH;BYMONTH=6,7,8
+
+ ==> (1997 9:00 AM EDT) June 5,12,19,26;July 3,10,17,24,31;
+ August 7,14,21,28
+ (1998 9:00 AM EDT) June 4,11,18,25;July 2,9,16,23,30;
+ August 6,13,20,27
+ (1999 9:00 AM EDT) June 3,10,17,24;July 1,8,15,22,29;
+ August 5,12,19,26
+ ...
+
+ Every Friday the 13th, forever:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ EXDATE;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=MONTHLY;BYDAY=FR;BYMONTHDAY=13
+
+ ==> (1998 9:00 AM EST) February 13;March 13;November 13
+ (1999 9:00 AM EDT) August 13
+ (2000 9:00 AM EDT) October 13
+ ...
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 129]
+
+RFC 5545 iCalendar September 2009
+
+
+ The first Saturday that follows the first Sunday of the month,
+ forever:
+
+ DTSTART;TZID=America/New_York:19970913T090000
+ RRULE:FREQ=MONTHLY;BYDAY=SA;BYMONTHDAY=7,8,9,10,11,12,13
+
+ ==> (1997 9:00 AM EDT) September 13;October 11
+ (1997 9:00 AM EST) November 8;December 13
+ (1998 9:00 AM EST) January 10;February 7;March 7
+ (1998 9:00 AM EDT) April 11;May 9;June 13...
+ ...
+
+ Every 4 years, the first Tuesday after a Monday in November,
+ forever (U.S. Presidential Election day):
+
+ DTSTART;TZID=America/New_York:19961105T090000
+ RRULE:FREQ=YEARLY;INTERVAL=4;BYMONTH=11;BYDAY=TU;
+ BYMONTHDAY=2,3,4,5,6,7,8
+
+ ==> (1996 9:00 AM EST) November 5
+ (2000 9:00 AM EST) November 7
+ (2004 9:00 AM EST) November 2
+ ...
+
+ The third instance into the month of one of Tuesday, Wednesday, or
+ Thursday, for the next 3 months:
+
+ DTSTART;TZID=America/New_York:19970904T090000
+ RRULE:FREQ=MONTHLY;COUNT=3;BYDAY=TU,WE,TH;BYSETPOS=3
+
+ ==> (1997 9:00 AM EDT) September 4;October 7
+ (1997 9:00 AM EST) November 6
+
+ The second-to-last weekday of the month:
+
+ DTSTART;TZID=America/New_York:19970929T090000
+ RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-2
+
+ ==> (1997 9:00 AM EDT) September 29
+ (1997 9:00 AM EST) October 30;November 27;December 30
+ (1998 9:00 AM EST) January 29;February 26;March 30
+ ...
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 130]
+
+RFC 5545 iCalendar September 2009
+
+
+ Every 3 hours from 9:00 AM to 5:00 PM on a specific day:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=HOURLY;INTERVAL=3;UNTIL=19970902T170000Z
+
+ ==> (September 2, 1997 EDT) 09:00,12:00,15:00
+
+ Every 15 minutes for 6 occurrences:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=MINUTELY;INTERVAL=15;COUNT=6
+
+ ==> (September 2, 1997 EDT) 09:00,09:15,09:30,09:45,10:00,10:15
+
+ Every hour and a half for 4 occurrences:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=MINUTELY;INTERVAL=90;COUNT=4
+
+ ==> (September 2, 1997 EDT) 09:00,10:30;12:00;13:30
+
+ Every 20 minutes from 9:00 AM to 4:40 PM every day:
+
+ DTSTART;TZID=America/New_York:19970902T090000
+ RRULE:FREQ=DAILY;BYHOUR=9,10,11,12,13,14,15,16;BYMINUTE=0,20,40
+ or
+ RRULE:FREQ=MINUTELY;INTERVAL=20;BYHOUR=9,10,11,12,13,14,15,16
+
+ ==> (September 2, 1997 EDT) 9:00,9:20,9:40,10:00,10:20,
+ ... 16:00,16:20,16:40
+ (September 3, 1997 EDT) 9:00,9:20,9:40,10:00,10:20,
+ ...16:00,16:20,16:40
+ ...
+
+ An example where the days generated makes a difference because of
+ WKST:
+
+ DTSTART;TZID=America/New_York:19970805T090000
+ RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=MO
+
+ ==> (1997 EDT) August 5,10,19,24
+
+ changing only WKST from MO to SU, yields different results...
+
+ DTSTART;TZID=America/New_York:19970805T090000
+ RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=SU
+
+ ==> (1997 EDT) August 5,17,19,31
+
+
+
+Desruisseaux Standards Track [Page 131]
+
+RFC 5545 iCalendar September 2009
+
+
+ An example where an invalid date (i.e., February 30) is ignored.
+
+ DTSTART;TZID=America/New_York:20070115T090000
+ RRULE:FREQ=MONTHLY;BYMONTHDAY=15,30;COUNT=5
+
+ ==> (2007 EST) January 15,30
+ (2007 EST) February 15
+ (2007 EDT) March 15,30
+
+3.8.6. Alarm Component Properties
+
+ The following properties specify alarm information in calendar
+ components.
+
+3.8.6.1. Action
+
+ Property Name: ACTION
+
+ Purpose: This property defines the action to be invoked when an
+ alarm is triggered.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property MUST be specified once in a "VALARM"
+ calendar component.
+
+ Description: Each "VALARM" calendar component has a particular type
+ of action with which it is associated. This property specifies
+ the type of action. Applications MUST ignore alarms with x-name
+ and iana-token values they don't recognize.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ action = "ACTION" actionparam ":" actionvalue CRLF
+
+ actionparam = *(";" other-param)
+
+
+ actionvalue = "AUDIO" / "DISPLAY" / "EMAIL"
+ / iana-token / x-name
+
+ Example: The following are examples of this property in a "VALARM"
+ calendar component:
+
+
+
+
+Desruisseaux Standards Track [Page 132]
+
+RFC 5545 iCalendar September 2009
+
+
+ ACTION:AUDIO
+
+ ACTION:DISPLAY
+
+3.8.6.2. Repeat Count
+
+ Property Name: REPEAT
+
+ Purpose: This property defines the number of times the alarm should
+ be repeated, after the initial trigger.
+
+ Value Type: INTEGER
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified in a "VALARM" calendar
+ component.
+
+ Description: This property defines the number of times an alarm
+ should be repeated after its initial trigger. If the alarm
+ triggers more than once, then this property MUST be specified
+ along with the "DURATION" property.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ repeat = "REPEAT" repparam ":" integer CRLF
+ ;Default is "0", zero.
+
+ repparam = *(";" other-param)
+
+ Example: The following is an example of this property for an alarm
+ that repeats 4 additional times with a 5-minute delay after the
+ initial triggering of the alarm:
+
+ REPEAT:4
+ DURATION:PT5M
+
+3.8.6.3. Trigger
+
+ Property Name: TRIGGER
+
+ Purpose: This property specifies when an alarm will trigger.
+
+ Value Type: The default value type is DURATION. The value type can
+ be set to a DATE-TIME value type, in which case the value MUST
+ specify a UTC-formatted DATE-TIME value.
+
+
+
+Desruisseaux Standards Track [Page 133]
+
+RFC 5545 iCalendar September 2009
+
+
+ Property Parameters: IANA, non-standard, value data type, time zone
+ identifier, or trigger relationship property parameters can be
+ specified on this property. The trigger relationship property
+ parameter MUST only be specified when the value type is
+ "DURATION".
+
+ Conformance: This property MUST be specified in the "VALARM"
+ calendar component.
+
+ Description: This property defines when an alarm will trigger. The
+ default value type is DURATION, specifying a relative time for the
+ trigger of the alarm. The default duration is relative to the
+ start of an event or to-do with which the alarm is associated.
+ The duration can be explicitly set to trigger from either the end
+ or the start of the associated event or to-do with the "RELATED"
+ parameter. A value of START will set the alarm to trigger off the
+ start of the associated event or to-do. A value of END will set
+ the alarm to trigger off the end of the associated event or to-do.
+
+ Either a positive or negative duration may be specified for the
+ "TRIGGER" property. An alarm with a positive duration is
+ triggered after the associated start or end of the event or to-do.
+ An alarm with a negative duration is triggered before the
+ associated start or end of the event or to-do.
+
+ The "RELATED" property parameter is not valid if the value type of
+ the property is set to DATE-TIME (i.e., for an absolute date and
+ time alarm trigger). If a value type of DATE-TIME is specified,
+ then the property value MUST be specified in the UTC time format.
+ If an absolute trigger is specified on an alarm for a recurring
+ event or to-do, then the alarm will only trigger for the specified
+ absolute DATE-TIME, along with any specified repeating instances.
+
+ If the trigger is set relative to START, then the "DTSTART"
+ property MUST be present in the associated "VEVENT" or "VTODO"
+ calendar component. If an alarm is specified for an event with
+ the trigger set relative to the END, then the "DTEND" property or
+ the "DTSTART" and "DURATION " properties MUST be present in the
+ associated "VEVENT" calendar component. If the alarm is specified
+ for a to-do with a trigger set relative to the END, then either
+ the "DUE" property or the "DTSTART" and "DURATION " properties
+ MUST be present in the associated "VTODO" calendar component.
+
+ Alarms specified in an event or to-do that is defined in terms of
+ a DATE value type will be triggered relative to 00:00:00 of the
+ user's configured time zone on the specified date, or relative to
+ 00:00:00 UTC on the specified date if no configured time zone can
+ be found for the user. For example, if "DTSTART" is a DATE value
+
+
+
+Desruisseaux Standards Track [Page 134]
+
+RFC 5545 iCalendar September 2009
+
+
+ set to 19980205 then the duration trigger will be relative to
+ 19980205T000000 America/New_York for a user configured with the
+ America/New_York time zone.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ trigger = "TRIGGER" (trigrel / trigabs) CRLF
+
+ trigrel = *(
+ ;
+ ; The following are OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" "VALUE" "=" "DURATION") /
+ (";" trigrelparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ ) ":" dur-value
+
+ trigabs = *(
+ ;
+ ; The following is REQUIRED,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" "VALUE" "=" "DATE-TIME") /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ ) ":" date-time
+
+ Example: A trigger set 15 minutes prior to the start of the event or
+ to-do.
+
+ TRIGGER:-PT15M
+
+ A trigger set five minutes after the end of an event or the due
+ date of a to-do.
+
+ TRIGGER;RELATED=END:PT5M
+
+
+
+
+Desruisseaux Standards Track [Page 135]
+
+RFC 5545 iCalendar September 2009
+
+
+ A trigger set to an absolute DATE-TIME.
+
+ TRIGGER;VALUE=DATE-TIME:19980101T050000Z
+
+3.8.7. Change Management Component Properties
+
+ The following properties specify change management information in
+ calendar components.
+
+3.8.7.1. Date-Time Created
+
+ Property Name: CREATED
+
+ Purpose: This property specifies the date and time that the calendar
+ information was created by the calendar user agent in the calendar
+ store.
+
+ Note: This is analogous to the creation date and time for a
+ file in the file system.
+
+ Value Type: DATE-TIME
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: The property can be specified once in "VEVENT",
+ "VTODO", or "VJOURNAL" calendar components. The value MUST be
+ specified as a date with UTC time.
+
+ Description: This property specifies the date and time that the
+ calendar information was created by the calendar user agent in the
+ calendar store.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ created = "CREATED" creaparam ":" date-time CRLF
+
+ creaparam = *(";" other-param)
+
+ Example: The following is an example of this property:
+
+ CREATED:19960329T133000Z
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 136]
+
+RFC 5545 iCalendar September 2009
+
+
+3.8.7.2. Date-Time Stamp
+
+ Property Name: DTSTAMP
+
+ Purpose: In the case of an iCalendar object that specifies a
+ "METHOD" property, this property specifies the date and time that
+ the instance of the iCalendar object was created. In the case of
+ an iCalendar object that doesn't specify a "METHOD" property, this
+ property specifies the date and time that the information
+ associated with the calendar component was last revised in the
+ calendar store.
+
+ Value Type: DATE-TIME
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property MUST be included in the "VEVENT",
+ "VTODO", "VJOURNAL", or "VFREEBUSY" calendar components.
+
+ Description: The value MUST be specified in the UTC time format.
+
+ This property is also useful to protocols such as [2447bis] that
+ have inherent latency issues with the delivery of content. This
+ property will assist in the proper sequencing of messages
+ containing iCalendar objects.
+
+ In the case of an iCalendar object that specifies a "METHOD"
+ property, this property differs from the "CREATED" and "LAST-
+ MODIFIED" properties. These two properties are used to specify
+ when the particular calendar data in the calendar store was
+ created and last modified. This is different than when the
+ iCalendar object representation of the calendar service
+ information was created or last modified.
+
+ In the case of an iCalendar object that doesn't specify a "METHOD"
+ property, this property is equivalent to the "LAST-MODIFIED"
+ property.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ dtstamp = "DTSTAMP" stmparam ":" date-time CRLF
+
+ stmparam = *(";" other-param)
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 137]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example:
+
+ DTSTAMP:19971210T080000Z
+
+3.8.7.3. Last Modified
+
+ Property Name: LAST-MODIFIED
+
+ Purpose: This property specifies the date and time that the
+ information associated with the calendar component was last
+ revised in the calendar store.
+
+ Note: This is analogous to the modification date and time for a
+ file in the file system.
+
+ Value Type: DATE-TIME
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+ Conformance: This property can be specified in the "VEVENT",
+ "VTODO", "VJOURNAL", or "VTIMEZONE" calendar components.
+
+ Description: The property value MUST be specified in the UTC time
+ format.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ last-mod = "LAST-MODIFIED" lstparam ":" date-time CRLF
+
+ lstparam = *(";" other-param)
+
+ Example: The following is an example of this property:
+
+ LAST-MODIFIED:19960817T133000Z
+
+3.8.7.4. Sequence Number
+
+ Property Name: SEQUENCE
+
+ Purpose: This property defines the revision sequence number of the
+ calendar component within a sequence of revisions.
+
+ Value Type: INTEGER
+
+ Property Parameters: IANA and non-standard property parameters can
+ be specified on this property.
+
+
+
+Desruisseaux Standards Track [Page 138]
+
+RFC 5545 iCalendar September 2009
+
+
+ Conformance: The property can be specified in "VEVENT", "VTODO", or
+ "VJOURNAL" calendar component.
+
+ Description: When a calendar component is created, its sequence
+ number is 0. It is monotonically incremented by the "Organizer's"
+ CUA each time the "Organizer" makes a significant revision to the
+ calendar component.
+
+ The "Organizer" includes this property in an iCalendar object that
+ it sends to an "Attendee" to specify the current version of the
+ calendar component.
+
+ The "Attendee" includes this property in an iCalendar object that
+ it sends to the "Organizer" to specify the version of the calendar
+ component to which the "Attendee" is referring.
+
+ A change to the sequence number is not the mechanism that an
+ "Organizer" uses to request a response from the "Attendees". The
+ "RSVP" parameter on the "ATTENDEE" property is used by the
+ "Organizer" to indicate that a response from the "Attendees" is
+ requested.
+
+ Recurrence instances of a recurring component MAY have different
+ sequence numbers.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ seq = "SEQUENCE" seqparam ":" integer CRLF
+ ; Default is "0"
+
+ seqparam = *(";" other-param)
+
+ Example: The following is an example of this property for a calendar
+ component that was just created by the "Organizer":
+
+ SEQUENCE:0
+
+ The following is an example of this property for a calendar
+ component that has been revised two different times by the
+ "Organizer":
+
+ SEQUENCE:2
+
+3.8.8. Miscellaneous Component Properties
+
+ The following properties specify information about a number of
+ miscellaneous features of calendar components.
+
+
+
+Desruisseaux Standards Track [Page 139]
+
+RFC 5545 iCalendar September 2009
+
+
+3.8.8.1. IANA Properties
+
+ Property Name: An IANA-registered property name
+
+ Value Type: The default value type is TEXT. The value type can be
+ set to any value type.
+
+ Property Parameters: Any parameter can be specified on this
+ property.
+
+ Description: This specification allows other properties registered
+ with IANA to be specified in any calendar components. Compliant
+ applications are expected to be able to parse these other IANA-
+ registered properties but can ignore them.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ iana-prop = iana-token *(";" icalparameter) ":" value CRLF
+
+ Example: The following are examples of properties that might be
+ registered to IANA:
+
+ DRESSCODE:CASUAL
+
+ NON-SMOKING;VALUE=BOOLEAN:TRUE
+
+3.8.8.2. Non-Standard Properties
+
+ Property Name: Any property name with a "X-" prefix
+
+ Purpose: This class of property provides a framework for defining
+ non-standard properties.
+
+ Value Type: The default value type is TEXT. The value type can be
+ set to any value type.
+
+ Property Parameters: IANA, non-standard, and language property
+ parameters can be specified on this property.
+
+ Conformance: This property can be specified in any calendar
+ component.
+
+ Description: The MIME Calendaring and Scheduling Content Type
+ provides a "standard mechanism for doing non-standard things".
+ This extension support is provided for implementers to "push the
+ envelope" on the existing version of the memo. Extension
+ properties are specified by property and/or property parameter
+
+
+
+Desruisseaux Standards Track [Page 140]
+
+RFC 5545 iCalendar September 2009
+
+
+ names that have the prefix text of "X-" (the two-character
+ sequence: LATIN CAPITAL LETTER X character followed by the HYPHEN-
+ MINUS character). It is recommended that vendors concatenate onto
+ this sentinel another short prefix text to identify the vendor.
+ This will facilitate readability of the extensions and minimize
+ possible collision of names between different vendors. User
+ agents that support this content type are expected to be able to
+ parse the extension properties and property parameters but can
+ ignore them.
+
+ At present, there is no registration authority for names of
+ extension properties and property parameters. The value type for
+ this property is TEXT. Optionally, the value type can be any of
+ the other valid value types.
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ x-prop = x-name *(";" icalparameter) ":" value CRLF
+
+ Example: The following might be the ABC vendor's extension for an
+ audio-clip form of subject property:
+
+ X-ABC-MMSUBJ;VALUE=URI;FMTTYPE=audio/basic:http://www.example.
+ org/mysubj.au
+
+3.8.8.3. Request Status
+
+ Property Name: REQUEST-STATUS
+
+ Purpose: This property defines the status code returned for a
+ scheduling request.
+
+ Value Type: TEXT
+
+ Property Parameters: IANA, non-standard, and language property
+ parameters can be specified on this property.
+
+ Conformance: The property can be specified in the "VEVENT", "VTODO",
+ "VJOURNAL", or "VFREEBUSY" calendar component.
+
+ Description: This property is used to return status code information
+ related to the processing of an associated iCalendar object. The
+ value type for this property is TEXT.
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 141]
+
+RFC 5545 iCalendar September 2009
+
+
+ The value consists of a short return status component, a longer
+ return status description component, and optionally a status-
+ specific data component. The components of the value are
+ separated by the SEMICOLON character.
+
+ The short return status is a PERIOD character separated pair or
+ 3-tuple of integers. For example, "3.1" or "3.1.1". The
+ successive levels of integers provide for a successive level of
+ status code granularity.
+
+ The following are initial classes for the return status code.
+ Individual iCalendar object methods will define specific return
+ status codes for these classes. In addition, other classes for
+ the return status code may be defined using the registration
+ process defined later in this memo.
+
+ +--------+----------------------------------------------------------+
+ | Short | Longer Return Status Description |
+ | Return | |
+ | Status | |
+ | Code | |
+ +--------+----------------------------------------------------------+
+ | 1.xx | Preliminary success. This class of status code |
+ | | indicates that the request has been initially processed |
+ | | but that completion is pending. |
+ | | |
+ | 2.xx | Successful. This class of status code indicates that |
+ | | the request was completed successfully. However, the |
+ | | exact status code can indicate that a fallback has been |
+ | | taken. |
+ | | |
+ | 3.xx | Client Error. This class of status code indicates that |
+ | | the request was not successful. The error is the result |
+ | | of either a syntax or a semantic error in the client- |
+ | | formatted request. Request should not be retried until |
+ | | the condition in the request is corrected. |
+ | | |
+ | 4.xx | Scheduling Error. This class of status code indicates |
+ | | that the request was not successful. Some sort of error |
+ | | occurred within the calendaring and scheduling service, |
+ | | not directly related to the request itself. |
+ +--------+----------------------------------------------------------+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 142]
+
+RFC 5545 iCalendar September 2009
+
+
+ Format Definition: This property is defined by the following
+ notation:
+
+ rstatus = "REQUEST-STATUS" rstatparam ":"
+ statcode ";" statdesc [";" extdata]
+
+ rstatparam = *(
+ ;
+ ; The following is OPTIONAL,
+ ; but MUST NOT occur more than once.
+ ;
+ (";" languageparam) /
+ ;
+ ; The following is OPTIONAL,
+ ; and MAY occur more than once.
+ ;
+ (";" other-param)
+ ;
+ )
+
+ statcode = 1*DIGIT 1*2("." 1*DIGIT)
+ ;Hierarchical, numeric return status code
+
+ statdesc = text
+ ;Textual status description
+
+ extdata = text
+ ;Textual exception data. For example, the offending property
+ ;name and value or complete property line.
+
+ Example: The following are some possible examples of this property.
+
+ The COMMA and SEMICOLON separator characters in the property value
+ are BACKSLASH character escaped because they appear in a text
+ value.
+
+ REQUEST-STATUS:2.0;Success
+
+ REQUEST-STATUS:3.1;Invalid property value;DTSTART:96-Apr-01
+
+ REQUEST-STATUS:2.8; Success\, repeating event ignored. Scheduled
+ as a single event.;RRULE:FREQ=WEEKLY\;INTERVAL=2
+
+ REQUEST-STATUS:4.1;Event conflict. Date-time is busy.
+
+ REQUEST-STATUS:3.7;Invalid calendar user;ATTENDEE:
+ mailto:jsmith@example.com
+
+
+
+
+Desruisseaux Standards Track [Page 143]
+
+RFC 5545 iCalendar September 2009
+
+
+4. iCalendar Object Examples
+
+ The following examples are provided as an informational source of
+ illustrative iCalendar objects consistent with this content type.
+
+ The following example specifies a three-day conference that begins at
+ 2:30 P.M. UTC, September 18, 1996 and ends at 10:00 P.M. UTC,
+ September 20, 1996.
+
+ BEGIN:VCALENDAR
+ PRODID:-//xyz Corp//NONSGML PDA Calendar Version 1.0//EN
+ VERSION:2.0
+ BEGIN:VEVENT
+ DTSTAMP:19960704T120000Z
+ UID:uid1@example.com
+ ORGANIZER:mailto:jsmith@example.com
+ DTSTART:19960918T143000Z
+ DTEND:19960920T220000Z
+ STATUS:CONFIRMED
+ CATEGORIES:CONFERENCE
+ SUMMARY:Networld+Interop Conference
+ DESCRIPTION:Networld+Interop Conference
+ and Exhibit\nAtlanta World Congress Center\n
+ Atlanta\, Georgia
+ END:VEVENT
+ END:VCALENDAR
+
+ The following example specifies a group-scheduled meeting that begins
+ at 8:30 AM EST on March 12, 1998 and ends at 9:30 AM EST on March 12,
+ 1998. The "Organizer" has scheduled the meeting with one or more
+ calendar users in a group. A time zone specification for Eastern
+ United States has been specified.
+
+ BEGIN:VCALENDAR
+ PRODID:-//RDU Software//NONSGML HandCal//EN
+ VERSION:2.0
+ BEGIN:VTIMEZONE
+ TZID:America/New_York
+ BEGIN:STANDARD
+ DTSTART:19981025T020000
+ TZOFFSETFROM:-0400
+ TZOFFSETTO:-0500
+ TZNAME:EST
+ END:STANDARD
+ BEGIN:DAYLIGHT
+ DTSTART:19990404T020000
+ TZOFFSETFROM:-0500
+ TZOFFSETTO:-0400
+
+
+
+Desruisseaux Standards Track [Page 144]
+
+RFC 5545 iCalendar September 2009
+
+
+ TZNAME:EDT
+ END:DAYLIGHT
+ END:VTIMEZONE
+ BEGIN:VEVENT
+ DTSTAMP:19980309T231000Z
+ UID:guid-1.example.com
+ ORGANIZER:mailto:mrbig@example.com
+ ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT;CUTYPE=GROUP:
+ mailto:employee-A@example.com
+ DESCRIPTION:Project XYZ Review Meeting
+ CATEGORIES:MEETING
+ CLASS:PUBLIC
+ CREATED:19980309T130000Z
+ SUMMARY:XYZ Project Review
+ DTSTART;TZID=America/New_York:19980312T083000
+ DTEND;TZID=America/New_York:19980312T093000
+ LOCATION:1CP Conference Room 4350
+ END:VEVENT
+ END:VCALENDAR
+
+ The following is an example of an iCalendar object passed in a MIME
+ message with a single body part consisting of a "text/calendar"
+ Content Type.
+
+ TO:jsmith@example.com
+ FROM:jdoe@example.com
+ MIME-VERSION:1.0
+ MESSAGE-ID:<id3@example.com>
+ CONTENT-TYPE:text/calendar; method="xyz"; component="VEVENT"
+
+ BEGIN:VCALENDAR
+ METHOD:xyz
+ VERSION:2.0
+ PRODID:-//ABC Corporation//NONSGML My Product//EN
+ BEGIN:VEVENT
+ DTSTAMP:19970324T120000Z
+ SEQUENCE:0
+ UID:uid3@example.com
+ ORGANIZER:mailto:jdoe@example.com
+ ATTENDEE;RSVP=TRUE:mailto:jsmith@example.com
+ DTSTART:19970324T123000Z
+ DTEND:19970324T210000Z
+ CATEGORIES:MEETING,PROJECT
+ CLASS:PUBLIC
+ SUMMARY:Calendaring Interoperability Planning Meeting
+ DESCRIPTION:Discuss how we can test c&s interoperability\n
+ using iCalendar and other IETF standards.
+ LOCATION:LDB Lobby
+
+
+
+Desruisseaux Standards Track [Page 145]
+
+RFC 5545 iCalendar September 2009
+
+
+ ATTACH;FMTTYPE=application/postscript:ftp://example.com/pub/
+ conf/bkgrnd.ps
+ END:VEVENT
+ END:VCALENDAR
+
+ The following is an example of a to-do due on April 15, 1998. An
+ audio alarm has been specified to remind the calendar user at noon,
+ the day before the to-do is expected to be completed and repeat
+ hourly, four additional times. The to-do definition has been
+ modified twice since it was initially created.
+
+ BEGIN:VCALENDAR
+ VERSION:2.0
+ PRODID:-//ABC Corporation//NONSGML My Product//EN
+ BEGIN:VTODO
+ DTSTAMP:19980130T134500Z
+ SEQUENCE:2
+ UID:uid4@example.com
+ ORGANIZER:mailto:unclesam@example.com
+ ATTENDEE;PARTSTAT=ACCEPTED:mailto:jqpublic@example.com
+ DUE:19980415T000000
+ STATUS:NEEDS-ACTION
+ SUMMARY:Submit Income Taxes
+ BEGIN:VALARM
+ ACTION:AUDIO
+ TRIGGER:19980403T120000Z
+ ATTACH;FMTTYPE=audio/basic:http://example.com/pub/audio-
+ files/ssbanner.aud
+ REPEAT:4
+ DURATION:PT1H
+ END:VALARM
+ END:VTODO
+ END:VCALENDAR
+
+ The following is an example of a journal entry:
+
+ BEGIN:VCALENDAR
+ VERSION:2.0
+ PRODID:-//ABC Corporation//NONSGML My Product//EN
+ BEGIN:VJOURNAL
+ DTSTAMP:19970324T120000Z
+ UID:uid5@example.com
+ ORGANIZER:mailto:jsmith@example.com
+ STATUS:DRAFT
+ CLASS:PUBLIC
+ CATEGORIES:Project Report,XYZ,Weekly Meeting
+ DESCRIPTION:Project xyz Review Meeting Minutes\n
+ Agenda\n1. Review of project version 1.0 requirements.\n2.
+
+
+
+Desruisseaux Standards Track [Page 146]
+
+RFC 5545 iCalendar September 2009
+
+
+ Definition
+ of project processes.\n3. Review of project schedule.\n
+ Participants: John Smith\, Jane Doe\, Jim Dandy\n-It was
+ decided that the requirements need to be signed off by
+ product marketing.\n-Project processes were accepted.\n
+ -Project schedule needs to account for scheduled holidays
+ and employee vacation time. Check with HR for specific
+ dates.\n-New schedule will be distributed by Friday.\n-
+ Next weeks meeting is cancelled. No meeting until 3/23.
+ END:VJOURNAL
+ END:VCALENDAR
+
+ The following is an example of published busy time information. The
+ iCalendar object might be placed in the network resource
+ http://www.example.com/calendar/busytime/jsmith.ifb.
+
+ BEGIN:VCALENDAR
+ VERSION:2.0
+ PRODID:-//RDU Software//NONSGML HandCal//EN
+ BEGIN:VFREEBUSY
+ ORGANIZER:mailto:jsmith@example.com
+ DTSTART:19980313T141711Z
+ DTEND:19980410T141711Z
+ FREEBUSY:19980314T233000Z/19980315T003000Z
+ FREEBUSY:19980316T153000Z/19980316T163000Z
+ FREEBUSY:19980318T030000Z/19980318T040000Z
+ URL:http://www.example.com/calendar/busytime/jsmith.ifb
+ END:VFREEBUSY
+ END:VCALENDAR
+
+5. Recommended Practices
+
+ These recommended practices should be followed in order to assure
+ consistent handling of the following cases for an iCalendar object.
+
+ 1. Content lines longer than 75 octets SHOULD be folded.
+
+ 2. When the combination of the "RRULE" and "RDATE" properties in a
+ recurring component produces multiple instances having the same
+ start DATE-TIME value, they should be collapsed to, and
+ considered as, a single instance. If the "RDATE" property is
+ specified as a PERIOD value the duration of the recurrence
+ instance will be the one specified by the "RDATE" property, and
+ not the duration of the recurrence instance defined by the
+ "DTSTART" property.
+
+ 3. When a calendar user receives multiple requests for the same
+ calendar component (e.g., REQUEST for a "VEVENT" calendar
+
+
+
+Desruisseaux Standards Track [Page 147]
+
+RFC 5545 iCalendar September 2009
+
+
+ component) as a result of being on multiple mailing lists
+ specified by "ATTENDEE" properties in the request, they SHOULD
+ respond to only one of the requests. The calendar user SHOULD
+ also specify (using the "MEMBER" parameter of the "ATTENDEE"
+ property) of which mailing list they are a member.
+
+ 4. An implementation can truncate a "SUMMARY" property value to 255
+ octets, but it MUST NOT truncate the value in the middle of a
+ UTF-8 multi-octet sequence.
+
+ 5. If seconds of the minute are not supported by an implementation,
+ then a value of "00" SHOULD be specified for the seconds
+ component in a time value.
+
+ 6. "TZURL" values SHOULD NOT be specified as a file URI type. This
+ URI form can be useful within an organization, but is problematic
+ in the Internet.
+
+ 7. Some possible English values for "CATEGORIES" property include:
+ "ANNIVERSARY", "APPOINTMENT", "BUSINESS", "EDUCATION", "HOLIDAY",
+ "MEETING", "MISCELLANEOUS", "NON-WORKING HOURS", "NOT IN OFFICE",
+ "PERSONAL", "PHONE CALL", "SICK DAY", "SPECIAL OCCASION",
+ "TRAVEL", "VACATION". Categories can be specified in any
+ registered language.
+
+ 8. Some possible English values for the "RESOURCES" property
+ include: "CATERING", "CHAIRS", "COMPUTER PROJECTOR", "EASEL",
+ "OVERHEAD PROJECTOR", "SPEAKER PHONE", "TABLE", "TV", "VCR",
+ "VIDEO PHONE", "VEHICLE". Resources can be specified in any
+ registered language.
+
+6. Internationalization Considerations
+
+ Applications MUST generate iCalendar streams in the UTF-8 charset and
+ MUST accept an iCalendar stream in the UTF-8 or US-ASCII charset.
+
+7. Security Considerations
+
+ Because calendaring and scheduling information is very privacy-
+ sensitive, the protocol used for the transmission of calendaring and
+ scheduling information should have capabilities to protect the
+ information from possible threats, such as eavesdropping, replay,
+ message insertion, deletion, modification, and man-in-the-middle
+ attacks.
+
+ As this document only defines the data format and media type of text/
+ calendar that is independent of any calendar service or protocol, it
+ is up to the actual protocol specifications such as iTIP [2446bis],
+
+
+
+Desruisseaux Standards Track [Page 148]
+
+RFC 5545 iCalendar September 2009
+
+
+ iMIP [2447bis], and "Calendaring Extensions to WebDAV (CalDAV)"
+ [RFC4791] to describe the threats that the above attacks present, as
+ well as ways in which to mitigate them.
+
+8. IANA Considerations
+
+8.1. iCalendar Media Type Registration
+
+ The Calendaring and Scheduling Core Object Specification is intended
+ for use as a MIME content type.
+
+ To: ietf-types@iana.org
+
+ Subject: Registration of media type text/calendar
+
+ Type name: text
+
+ Subtype name: calendar
+
+ Required parameters: none
+
+ Optional parameters: charset, method, component, and optinfo
+
+ The "charset" parameter is defined in [RFC2046] for subtypes of
+ the "text" media type. It is used to indicate the charset used in
+ the body part. The charset supported by this revision of
+ iCalendar is UTF-8. The use of any other charset is deprecated by
+ this revision of iCalendar; however, note that this revision
+ requires that compliant applications MUST accept iCalendar streams
+ using either the UTF-8 or US-ASCII charset.
+
+ The "method" parameter is used to convey the iCalendar object
+ method or transaction semantics for the calendaring and scheduling
+ information. It also is an identifier for the restricted set of
+ properties and values of which the iCalendar object consists. The
+ parameter is to be used as a guide for applications interpreting
+ the information contained within the body part. It SHOULD NOT be
+ used to exclude or require particular pieces of information unless
+ the identified method definition specifically calls for this
+ behavior. Unless specifically forbidden by a particular method
+ definition, a text/calendar content type can contain any set of
+ properties permitted by the Calendaring and Scheduling Core Object
+ Specification. The "method" parameter MUST be specified and MUST
+ be set to the same value as the "METHOD" component property of the
+ iCalendar objects of the iCalendar stream if and only if the
+ iCalendar objects in the iCalendar stream all have a "METHOD"
+ component property set to the same value.
+
+
+
+
+Desruisseaux Standards Track [Page 149]
+
+RFC 5545 iCalendar September 2009
+
+
+ The value for the "method" parameter is defined as follows:
+
+ method = 1*(ALPHA / DIGIT / "-")
+ ; IANA-registered iCalendar object method
+
+ The "component" parameter conveys the type of iCalendar calendar
+ component within the body part. If the iCalendar object contains
+ more than one calendar component type, then multiple component
+ parameters MUST be specified.
+
+ The value for the "component" parameter is defined as follows:
+
+ component = "VEVENT"
+ / "VTODO"
+ / "VJOURNAL"
+ / "VFREEBUSY"
+ / "VTIMEZONE"
+ / iana-token
+ / x-name
+
+ The "optinfo" parameter conveys optional information about the
+ iCalendar object within the body part. This parameter can only
+ specify semantics already specified by the iCalendar object and
+ that can be otherwise determined by parsing the body part. In
+ addition, the optional information specified by this parameter
+ MUST be consistent with that information specified by the
+ iCalendar object. For example, it can be used to convey the
+ "Attendee" response status to a meeting request. The parameter
+ value consists of a string value.
+
+ The parameter can be specified multiple times.
+
+ The value for the "optinfo" parameter is defined as follows:
+
+ optinfo = infovalue / qinfovalue
+
+ infovalue = iana-token / x-name
+
+ qinfovalue = DQUOTE (infovalue) DQUOTE
+
+ Encoding considerations: This media type can contain 8bit
+ characters, so the use of quoted-printable or base64 MIME Content-
+ Transfer-Encodings might be necessary when iCalendar objects are
+ transferred across protocols restricted to the 7bit repertoire.
+ Note that a text valued property in the content entity can also
+ have content encoding of special characters using a BACKSLASH
+ character escapement technique. This means that content values
+ can end up being encoded twice.
+
+
+
+Desruisseaux Standards Track [Page 150]
+
+RFC 5545 iCalendar September 2009
+
+
+ Security considerations: See Section 7.
+
+ Interoperability considerations: This media type is intended to
+ define a common format for conveying calendaring and scheduling
+ information between different systems. It is heavily based on the
+ earlier [VCAL] industry specification.
+
+ Published specification: This specification.
+
+ Applications that use this media type: This media type is designed
+ for widespread use by Internet calendaring and scheduling
+ applications. In addition, applications in the workflow and
+ document management area might find this content-type applicable.
+ The iTIP [2446bis], iMIP [2447bis], and CalDAV [RFC4791] Internet
+ protocols directly use this media type also.
+
+ Additional information:
+
+ Magic number(s): None.
+
+ File extension(s): The file extension of "ics" is to be used to
+ designate a file containing (an arbitrary set of) calendaring
+ and scheduling information consistent with this MIME content
+ type.
+
+ The file extension of "ifb" is to be used to designate a file
+ containing free or busy time information consistent with this
+ MIME content type.
+
+ Macintosh file type code(s): The file type code of "iCal" is to
+ be used in Apple MacIntosh operating system environments to
+ designate a file containing calendaring and scheduling
+ information consistent with this MIME media type.
+
+ The file type code of "iFBf" is to be used in Apple MacIntosh
+ operating system environments to designate a file containing
+ free or busy time information consistent with this MIME media
+ type.
+
+ 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.
+
+
+
+Desruisseaux Standards Track [Page 151]
+
+RFC 5545 iCalendar September 2009
+
+
+ Change controller: IETF
+
+8.2. New iCalendar Elements Registration
+
+ This section defines the process to register new or modified
+ iCalendar elements, that is, components, properties, parameters,
+ value data types, and values, with IANA.
+
+8.2.1. iCalendar Elements Registration Procedure
+
+ The IETF will create a mailing list, icalendar@ietf.org, which can be
+ used for public discussion of iCalendar elements proposals prior to
+ registration. Use of the mailing list is strongly encouraged. The
+ IESG will appoint a designated expert who will monitor the
+ icalendar@ietf.org mailing list and review registrations.
+
+ Registration of new iCalendar elements MUST be reviewed by the
+ designated expert and published in an RFC. A Standards Track RFC is
+ REQUIRED for the registration of new value data types that modify
+ existing properties, as well as for the registration of participation
+ status values to be used in "VEVENT" calendar components. A
+ Standards Track RFC is also REQUIRED for registration of iCalendar
+ elements that modify iCalendar elements previously documented in a
+ Standards Track RFC.
+
+ The registration procedure begins when a completed registration
+ template, defined in the sections below, is sent to
+ icalendar@ietf.org and iana@iana.org. The designated expert is
+ expected to tell IANA and the submitter of the registration within
+ two weeks whether the registration is approved, approved with minor
+ changes, or rejected with cause. When a registration is rejected
+ with cause, it can be re-submitted if the concerns listed in the
+ cause are addressed. Decisions made by the designated expert can be
+ appealed to the IESG Applications Area Director, then to the IESG.
+ They follow the normal appeals procedure for IESG decisions.
+
+8.2.2. Registration Template for Components
+
+ A component is defined by completing the following template.
+
+ Component name: The name of the component.
+
+ Purpose: The purpose of the component. Give a short but clear
+ description.
+
+ Format definition: The ABNF for the component definition needs to be
+ specified.
+
+
+
+
+Desruisseaux Standards Track [Page 152]
+
+RFC 5545 iCalendar September 2009
+
+
+ Description: Any special notes about the component, how it is to be
+ used, etc.
+
+ Example(s): One or more examples of instances of the component need
+ to be specified.
+
+8.2.3. Registration Template for Properties
+
+ A property is defined by completing the following template.
+
+ Property name: The name of the property.
+
+ Purpose: The purpose of the property. Give a short but clear
+ description.
+
+ Value type: Any of the valid value types for the property value need
+ to be specified. The default value type also needs to be
+ specified.
+
+ Property parameters: Any of the valid property parameters for the
+ property MUST be specified.
+
+ Conformance: The calendar components in which the property can
+ appear MUST be specified.
+
+ Description: Any special notes about the property, how it is to be
+ used, etc.
+
+ Format definition: The ABNF for the property definition needs to be
+ specified.
+
+ Example(s): One or more examples of instances of the property need
+ to be specified.
+
+8.2.4. Registration Template for Parameters
+
+ A parameter is defined by completing the following template.
+
+ Parameter name: The name of the parameter.
+
+ Purpose: The purpose of the parameter. Give a short but clear
+ description.
+
+ Format definition: The ABNF for the parameter definition needs to be
+ specified.
+
+ Description: Any special notes about the parameter, how it is to be
+ used, etc.
+
+
+
+Desruisseaux Standards Track [Page 153]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example(s): One or more examples of instances of the parameter need
+ to be specified.
+
+8.2.5. Registration Template for Value Data Types
+
+ A value data type is defined by completing the following template.
+
+ Value name: The name of the value type.
+
+ Purpose: The purpose of the value type. Give a short but clear
+ description.
+
+ Format definition: The ABNF for the value type definition needs to
+ be specified.
+
+ Description: Any special notes about the value type, how it is to be
+ used, etc.
+
+ Example(s): One or more examples of instances of the value type need
+ to be specified.
+
+8.2.6. Registration Template for Values
+
+ A value is defined by completing the following template.
+
+ Value: The value literal.
+
+ Purpose: The purpose of the value. Give a short but clear
+ description.
+
+ Conformance: The calendar properties and/or parameters that can take
+ this value need to be specified.
+
+ Example(s): One or more examples of instances of the value need to
+ be specified.
+
+ The following is a fictitious example of a registration of an
+ iCalendar value:
+
+ Value: TOP-SECRET
+
+ Purpose: This value is used to specify the access classification of
+ top-secret calendar components.
+
+ Conformance: This value can be used with the "CLASS" property.
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 154]
+
+RFC 5545 iCalendar September 2009
+
+
+ Example(s): The following is an example of this value used with the
+ "CLASS" property:
+
+ CLASS:TOP-SECRET
+
+8.3. Initial iCalendar Elements Registries
+
+ The IANA created and maintains the following registries for iCalendar
+ elements with pointers to appropriate reference documents.
+
+8.3.1. Components Registry
+
+ The following table has been used to initialize the components
+ registry.
+
+ +-----------+---------+-------------------------+
+ | Component | Status | Reference |
+ +-----------+---------+-------------------------+
+ | VCALENDAR | Current | RFC 5545, Section 3.4 |
+ | | | |
+ | VEVENT | Current | RFC 5545, Section 3.6.1 |
+ | | | |
+ | VTODO | Current | RFC 5545, Section 3.6.2 |
+ | | | |
+ | VJOURNAL | Current | RFC 5545, Section 3.6.3 |
+ | | | |
+ | VFREEBUSY | Current | RFC 5545, Section 3.6.4 |
+ | | | |
+ | VTIMEZONE | Current | RFC 5545, Section 3.6.5 |
+ | | | |
+ | VALARM | Current | RFC 5545, Section 3.6.6 |
+ | | | |
+ | STANDARD | Current | RFC 5545, Section 3.6.5 |
+ | | | |
+ | DAYLIGHT | Current | RFC 5545, Section 3.6.5 |
+ +-----------+---------+-------------------------+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 155]
+
+RFC 5545 iCalendar September 2009
+
+
+8.3.2. Properties Registry
+
+ The following table is has been used to initialize the properties
+ registry.
+
+ +------------------+------------+----------------------------+
+ | Property | Status | Reference |
+ +------------------+------------+----------------------------+
+ | CALSCALE | Current | RFC 5545, Section 3.7.1 |
+ | METHOD | Current | RFC 5545, Section 3.7.2 |
+ | | | |
+ | PRODID | Current | RFC 5545, Section 3.7.3 |
+ | | | |
+ | VERSION | Current | RFC 5545, Section 3.7.4 |
+ | | | |
+ | ATTACH | Current | RFC 5545, Section 3.8.1.1 |
+ | | | |
+ | CATEGORIES | Current | RFC 5545, Section 3.8.1.2 |
+ | | | |
+ | CLASS | Current | RFC 5545, Section 3.8.1.3 |
+ | | | |
+ | COMMENT | Current | RFC 5545, Section 3.8.1.4 |
+ | | | |
+ | DESCRIPTION | Current | RFC 5545, Section 3.8.1.5 |
+ | | | |
+ | GEO | Current | RFC 5545, Section 3.8.1.6 |
+ | | | |
+ | LOCATION | Current | RFC 5545, Section 3.8.1.7 |
+ | | | |
+ | PERCENT-COMPLETE | Current | RFC 5545, Section 3.8.1.8 |
+ | | | |
+ | PRIORITY | Current | RFC 5545, Section 3.8.1.9 |
+ | | | |
+ | RESOURCES | Current | RFC 5545, Section 3.8.1.10 |
+ | | | |
+ | STATUS | Current | RFC 5545, Section 3.8.1.11 |
+ | | | |
+ | SUMMARY | Current | RFC 5545, Section 3.8.1.12 |
+ | | | |
+ | COMPLETED | Current | RFC 5545, Section 3.8.2.1 |
+ | | | |
+ | DTEND | Current | RFC 5545, Section 3.8.2.2 |
+ | | | |
+ | DUE | Current | RFC 5545, Section 3.8.2.3 |
+ | | | |
+ | DTSTART | Current | RFC 5545, Section 3.8.2.4 |
+ | | | |
+ | DURATION | Current | RFC 5545, Section 3.8.2.5 |
+
+
+
+Desruisseaux Standards Track [Page 156]
+
+RFC 5545 iCalendar September 2009
+
+
+ | | | |
+ | FREEBUSY | Current | RFC 5545, Section 3.8.2.6 |
+ | | | |
+ | TRANSP | Current | RFC 5545, Section 3.8.2.7 |
+ | | | |
+ | TZID | Current | RFC 5545, Section 3.8.3.1 |
+ | | | |
+ | TZNAME | Current | RFC 5545, Section 3.8.3.2 |
+ | | | |
+ | TZOFFSETFROM | Current | RFC 5545, Section 3.8.3.3 |
+ | | | |
+ | TZOFFSETTO | Current | RFC 5545, Section 3.8.3.4 |
+ | | | |
+ | TZURL | Current | RFC 5545, Section 3.8.3.5 |
+ | | | |
+ | ATTENDEE | Current | RFC 5545, Section 3.8.4.1 |
+ | | | |
+ | CONTACT | Current | RFC 5545, Section 3.8.4.2 |
+ | | | |
+ | ORGANIZER | Current | RFC 5545, Section 3.8.4.3 |
+ | | | |
+ | RECURRENCE-ID | Current | RFC 5545, Section 3.8.4.4 |
+ | | | |
+ | RELATED-TO | Current | RFC 5545, Section 3.8.4.5 |
+ | | | |
+ | URL | Current | RFC 5545, Section 3.8.4.6 |
+ | | | |
+ | UID | Current | RFC 5545, Section 3.8.4.7 |
+ | | | |
+ | EXDATE | Current | RFC 5545, Section 3.8.5.1 |
+ | | | |
+ | EXRULE | Deprecated | [RFC2445], Section 4.8.5.2 |
+ | | | |
+ | RDATE | Current | RFC 5545, Section 3.8.5.2 |
+ | | | |
+ | RRULE | Current | RFC 5545, Section 3.8.5.3 |
+ | | | |
+ | ACTION | Current | RFC 5545, Section 3.8.6.1 |
+ | | | |
+ | REPEAT | Current | RFC 5545, Section 3.8.6.2 |
+ | | | |
+ | TRIGGER | Current | RFC 5545, Section 3.8.6.3 |
+ | | | |
+ | CREATED | Current | RFC 5545, Section 3.8.7.1 |
+ | | | |
+ | DTSTAMP | Current | RFC 5545, Section 3.8.7.2 |
+ | | | |
+ | LAST-MODIFIED | Current | RFC 5545, Section 3.8.7.3 |
+
+
+
+Desruisseaux Standards Track [Page 157]
+
+RFC 5545 iCalendar September 2009
+
+
+ | | | |
+ | SEQUENCE | Current | RFC 5545, Section 3.8.7.4 |
+ | | | |
+ | REQUEST-STATUS | Current | RFC 5545, Section 3.8.8.3 |
+ +------------------+------------+----------------------------+
+
+8.3.3. Parameters Registry
+
+ The following table has been used to initialize the parameters
+ registry.
+
+ +----------------+---------+--------------------------+
+ | Parameter | Status | Reference |
+ +----------------+---------+--------------------------+
+ | ALTREP | Current | RFC 5545, Section 3.2.1 |
+ | | | |
+ | CN | Current | RFC 5545, Section 3.2.2 |
+ | | | |
+ | CUTYPE | Current | RFC 5545, Section 3.2.3 |
+ | | | |
+ | DELEGATED-FROM | Current | RFC 5545, Section 3.2.4 |
+ | | | |
+ | DELEGATED-TO | Current | RFC 5545, Section 3.2.5 |
+ | | | |
+ | DIR | Current | RFC 5545, Section 3.2.6 |
+ | | | |
+ | ENCODING | Current | RFC 5545, Section 3.2.7 |
+ | | | |
+ | FMTTYPE | Current | RFC 5545, Section 3.2.8 |
+ | | | |
+ | FBTYPE | Current | RFC 5545, Section 3.2.9 |
+ | | | |
+ | LANGUAGE | Current | RFC 5545, Section 3.2.10 |
+ | | | |
+ | MEMBER | Current | RFC 5545, Section 3.2.11 |
+ | | | |
+ | PARTSTAT | Current | RFC 5545, Section 3.2.12 |
+ | | | |
+ | RANGE | Current | RFC 5545, Section 3.2.13 |
+ | | | |
+ | RELATED | Current | RFC 5545, Section 3.2.14 |
+ | | | |
+ | RELTYPE | Current | RFC 5545, Section 3.2.15 |
+ | | | |
+ | ROLE | Current | RFC 5545, Section 3.2.16 |
+ | | | |
+ | RSVP | Current | RFC 5545, Section 3.2.17 |
+ | | | |
+
+
+
+Desruisseaux Standards Track [Page 158]
+
+RFC 5545 iCalendar September 2009
+
+
+ | SENT-BY | Current | RFC 5545, Section 3.2.18 |
+ | | | |
+ | TZID | Current | RFC 5545, Section 3.2.19 |
+ | | | |
+ | VALUE | Current | RFC 5545, Section 3.2.20 |
+ +----------------+---------+--------------------------+
+
+8.3.4. Value Data Types Registry
+
+ The following table has been used to initialize the value data types
+ registry.
+
+ +-----------------+---------+--------------------------+
+ | Value Data Type | Status | Reference |
+ +-----------------+---------+--------------------------+
+ | BINARY | Current | RFC 5545, Section 3.3.1 |
+ | | | |
+ | BOOLEAN | Current | RFC 5545, Section 3.3.2 |
+ | | | |
+ | CAL-ADDRESS | Current | RFC 5545, Section 3.3.3 |
+ | | | |
+ | DATE | Current | RFC 5545, Section 3.3.4 |
+ | | | |
+ | DATE-TIME | Current | RFC 5545, Section 3.3.5 |
+ | | | |
+ | DURATION | Current | RFC 5545, Section 3.3.6 |
+ | | | |
+ | FLOAT | Current | RFC 5545, Section 3.3.7 |
+ | | | |
+ | INTEGER | Current | RFC 5545, Section 3.3.8 |
+ | | | |
+ | PERIOD | Current | RFC 5545, Section 3.3.9 |
+ | | | |
+ | RECUR | Current | RFC 5545, Section 3.3.10 |
+ | | | |
+ | TEXT | Current | RFC 5545, Section 3.3.11 |
+ | | | |
+ | TIME | Current | RFC 5545, Section 3.3.12 |
+ | | | |
+ | URI | Current | RFC 5545, Section 3.3.13 |
+ | | | |
+ | UTC-OFFSET | Current | RFC 5545, Section 3.3.14 |
+ +-----------------+---------+--------------------------+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 159]
+
+RFC 5545 iCalendar September 2009
+
+
+8.3.5. Calendar User Types Registry
+
+ The following table has been used to initialize the calendar user
+ types registry.
+
+ +--------------------+---------+-------------------------+
+ | Calendar User Type | Status | Reference |
+ +--------------------+---------+-------------------------+
+ | INDIVIDUAL | Current | RFC 5545, Section 3.2.3 |
+ | | | |
+ | GROUP | Current | RFC 5545, Section 3.2.3 |
+ | | | |
+ | RESOURCE | Current | RFC 5545, Section 3.2.3 |
+ | | | |
+ | ROOM | Current | RFC 5545, Section 3.2.3 |
+ | | | |
+ | UNKNOWN | Current | RFC 5545, Section 3.2.3 |
+ +--------------------+---------+-------------------------+
+
+8.3.6. Free/Busy Time Types Registry
+
+ The following table has been used to initialize the free/busy time
+ types registry.
+
+ +---------------------+---------+-------------------------+
+ | Free/Busy Time Type | Status | Reference |
+ +---------------------+---------+-------------------------+
+ | FREE | Current | RFC 5545, Section 3.2.9 |
+ | | | |
+ | BUSY | Current | RFC 5545, Section 3.2.9 |
+ | | | |
+ | BUSY-UNAVAILABLE | Current | RFC 5545, Section 3.2.9 |
+ | | | |
+ | BUSY-TENTATIVE | Current | RFC 5545, Section 3.2.9 |
+ +---------------------+---------+-------------------------+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 160]
+
+RFC 5545 iCalendar September 2009
+
+
+8.3.7. Participation Statuses Registry
+
+ The following table has been used to initialize the participation
+ statuses registry.
+
+ +--------------------+---------+--------------------------+
+ | Participant Status | Status | Reference |
+ +--------------------+---------+--------------------------+
+ | NEEDS-ACTION | Current | RFC 5545, Section 3.2.12 |
+ | | | |
+ | ACCEPTED | Current | RFC 5545, Section 3.2.12 |
+ | | | |
+ | DECLINED | Current | RFC 5545, Section 3.2.12 |
+ | | | |
+ | TENTATIVE | Current | RFC 5545, Section 3.2.12 |
+ | | | |
+ | DELEGATED | Current | RFC 5545, Section 3.2.12 |
+ | | | |
+ | COMPLETED | Current | RFC 5545, Section 3.2.12 |
+ | | | |
+ | IN-PROCESS | Current | RFC 5545, Section 3.2.12 |
+ +--------------------+---------+--------------------------+
+
+8.3.8. Relationship Types Registry
+
+ The following table has been used to initialize the relationship
+ types registry.
+
+ +-------------------+---------+--------------------------+
+ | Relationship Type | Status | Reference |
+ +-------------------+---------+--------------------------+
+ | CHILD | Current | RFC 5545, Section 3.2.15 |
+ | | | |
+ | PARENT | Current | RFC 5545, Section 3.2.15 |
+ | | | |
+ | SIBLING | Current | RFC 5545, Section 3.2.15 |
+ +-------------------+---------+--------------------------+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 161]
+
+RFC 5545 iCalendar September 2009
+
+
+8.3.9. Participation Roles Registry
+
+ The following table has been used to initialize the participation
+ roles registry.
+
+ +-----------------+---------+--------------------------+
+ | Role Type | Status | Reference |
+ +-----------------+---------+--------------------------+
+ | CHAIR | Current | RFC 5545, Section 3.2.16 |
+ | | | |
+ | REQ-PARTICIPANT | Current | RFC 5545, Section 3.2.16 |
+ | | | |
+ | OPT-PARTICIPANT | Current | RFC 5545, Section 3.2.16 |
+ | | | |
+ | NON-PARTICIPANT | Current | RFC 5545, Section 3.2.16 |
+ +-----------------+---------+--------------------------+
+
+8.3.10. Actions Registry
+
+ The following table has been used to initialize the actions registry.
+
+ +-----------+------------+----------------------------+
+ | Action | Status | Reference |
+ +-----------+------------+----------------------------+
+ | AUDIO | Current | RFC 5545, Section 3.8.6.1 |
+ | | | |
+ | DISPLAY | Current | RFC 5545, Section 3.8.6.1 |
+ | | | |
+ | EMAIL | Current | RFC 5545, Section 3.8.6.1 |
+ | | | |
+ | PROCEDURE | Deprecated | [RFC2445], Section 4.8.6.1 |
+ +-----------+------------+----------------------------+
+
+8.3.11. Classifications Registry
+
+ The following table has been used to initialize the classifications
+ registry.
+
+ +----------------+---------+---------------------------+
+ | Classification | Status | Reference |
+ +----------------+---------+---------------------------+
+ | PUBLIC | Current | RFC 5545, Section 3.8.1.3 |
+ | | | |
+ | PRIVATE | Current | RFC 5545, Section 3.8.1.3 |
+ | | | |
+ | CONFIDENTIAL | Current | RFC 5545, Section 3.8.1.3 |
+ +----------------+---------+---------------------------+
+
+
+
+
+Desruisseaux Standards Track [Page 162]
+
+RFC 5545 iCalendar September 2009
+
+
+8.3.12. Methods Registry
+
+ No values are defined in this document for the "METHOD" property.
+
+9. Acknowledgments
+
+ The editor of this document wishes to thank Frank Dawson and Derik
+ Stenerson, the original authors of RFC 2445, as well as the following
+ individuals who have participated in the drafting, review, and
+ discussion of this memo:
+
+ Joe Abley, Hervey Allen, Steve Allen, Jay Batson, Oliver Block,
+ Stephane Bortzmeyer, Chris Bryant, Tantek Celik, Mark Crispin, Cyrus
+ Daboo, Mike Douglass, Andrew N. Dowden, Lisa Dusseault, Lars Eggert,
+ Gren Eliot, Pasi Eronen, Ben Fortuna, Ned Freed, Neal Gafter, Ted
+ Hardie, Tim Hare, Jeffrey Harris, Helge Hess, Paul B. Hill, Thomas
+ Hnetila, Russ Housley, Leif Johansson, Ciny Joy, Bruce Kahn, Reinhold
+ Kainhofer, Martin Kiff, Patrice Lapierre, Michiel van Leeuwen,
+ Jonathan Lennox, Jeff McCullough, Bill McQuillan, Alexey Melnikov,
+ John W. Noerenberg II, Chuck Norris, Mark Paterson, Simon Pilette,
+ Arnaud Quillaud, Robert Ransdell, Julian F. Reschke, Caleb
+ Richardson, Sam Roberts, Dan Romascanu, Mike Samuel, George Sexton,
+ Nigel Swinson, Clint Talbert, Simon Vaillancourt, Magnus Westerlund,
+ and Sandy Wills.
+
+ A special thanks to the working group chairs Aki Niemi and Eliot Lear
+ for their support and guidance.
+
+ The editor would also like to thank the Calendaring and Scheduling
+ Consortium for advice with this specification, and for organizing
+ interoperability testing events to help refine it.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 163]
+
+RFC 5545 iCalendar September 2009
+
+
+10. References
+
+10.1. Normative References
+
+ [ISO.8601.2004] International Organization for
+ Standardization, "Data elements and
+ interchange formats -- Information interchange
+ -- Representation of dates and times", 2004.
+
+ [ISO.9070.1991] International Organization for
+ Standardization, "Information Technology_SGML
+ Support Facilities -- Registration Procedures
+ for Public Text Owner Identifiers, Second
+ Edition", April 1991.
+
+ [RFC2045] Freed, N. and N. Borenstein, "Multipurpose
+ Internet Mail Extensions (MIME) Part One:
+ Format of Internet Message Bodies", RFC 2045,
+ November 1996.
+
+ [RFC2046] Freed, N. and N. Borenstein, "Multipurpose
+ Internet Mail Extensions (MIME) Part Two:
+ Media Types", RFC 2046, November 1996.
+
+ [RFC2119] Bradner, S., "Key words for use in RFCs to
+ Indicate Requirement Levels", BCP 14,
+ RFC 2119, March 1997.
+
+ [RFC2368] Hoffman, P., Masinter, L., and J. Zawinski,
+ "The mailto URL scheme", RFC 2368, July 1998.
+
+ [RFC3629] Yergeau, F., "UTF-8, a transformation format
+ of ISO 10646", STD 63, RFC 3629,
+ November 2003.
+
+ [RFC3986] Berners-Lee, T., Fielding, R., and L.
+ Masinter, "Uniform Resource Identifier (URI):
+ Generic Syntax", STD 66, RFC 3986,
+ January 2005.
+
+ [RFC4288] Freed, N. and J. Klensin, "Media Type
+ Specifications and Registration Procedures",
+ BCP 13, RFC 4288, December 2005.
+
+ [RFC4648] Josefsson, S., "The Base16, Base32, and Base64
+ Data Encodings", RFC 4648, October 2006.
+
+
+
+
+
+Desruisseaux Standards Track [Page 164]
+
+RFC 5545 iCalendar September 2009
+
+
+ [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for
+ Syntax Specifications: ABNF", STD 68,
+ RFC 5234, January 2008.
+
+ [RFC5646] Phillips, A., Ed., and M. Davis, Ed., "Tags
+ for Identifying Languages", BCP 47, RFC 5646,
+ September 2009.
+
+ [US-ASCII] American National Standards Institute, "Coded
+ Character Set - 7-bit American Standard Code
+ for Information Interchange", ANSI X3.4, 1986.
+
+10.2. Informative References
+
+ [2446bis] Daboo, C., "iCalendar Transport-Independent
+ Interoperability Protocol (iTIP)", Work
+ in Progress, April 2009.
+
+ [2447bis] Melnikov, A., "iCalendar Message-Based
+ Interoperability Protocol (iMIP)", Work
+ in Progress, June 2008.
+
+ [ANSI INCITS 61-1986] International Committee for Information
+ Technology, "Representation of Geographic
+ Point Locations for Information Interchange
+ (formerly ANSI X3.61-1986 (R1997))", ANSI
+ INCITS 61-1986 (R2007), 2007.
+
+ [RFC1738] Berners-Lee, T., Masinter, L., and M.
+ McCahill, "Uniform Resource Locators (URL)",
+ RFC 1738, December 1994.
+
+ [RFC2392] Levinson, E., "Content-ID and Message-ID
+ Uniform Resource Locators", RFC 2392,
+ August 1998.
+
+ [RFC2397] Masinter, L., "The "data" URL scheme",
+ RFC 2397, August 1998.
+
+ [RFC2425] Howes, T., Smith, M., and F. Dawson, "A MIME
+ Content-Type for Directory Information",
+ RFC 2425, September 1998.
+
+ [RFC2426] Dawson, F. and T. Howes, "vCard MIME Directory
+ Profile", RFC 2426, September 1998.
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 165]
+
+RFC 5545 iCalendar September 2009
+
+
+ [RFC2445] Dawson, F. and Stenerson, D., "Internet
+ Calendaring and Scheduling Core Object
+ Specification (iCalendar)", RFC 2445,
+ November 1998.
+
+ [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.
+
+ [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
+ May 2000.
+
+ [RFC4516] Smith, M. and T. Howes, "Lightweight Directory
+ Access Protocol (LDAP): Uniform Resource
+ Locator", RFC 4516, June 2006.
+
+ [RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault,
+ "Calendaring Extensions to WebDAV (CalDAV)",
+ RFC 4791, March 2007.
+
+ [TZDB] Eggert, P. and A.D. Olson, "Sources for Time
+ Zone and Daylight Saving Time Data",
+ July 2009,
+ <http://www.twinsun.com/tz/tz-link.htm>.
+
+ [VCAL] Internet Mail Consortium, "vCalendar: The
+ Electronic Calendaring and Scheduling Exchange
+ Format", September 1996,
+ <http://www.imc.org/pdi/vcal-10.txt>.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 166]
+
+RFC 5545 iCalendar September 2009
+
+
+Appendix A. Differences from RFC 2445
+
+ This appendix contains a list of changes that have been made in the
+ Internet Calendaring and Scheduling Core Object Specification from
+ RFC 2445.
+
+A.1. New Restrictions
+
+ 1. The "DTSTART" property SHOULD be synchronized with the recurrence
+ rule, if specified.
+
+ 2. The "RRULE" property SHOULD NOT occur more than once in a
+ component.
+
+ 3. The BYHOUR, BYMINUTE, and BYSECOND rule parts MUST NOT be
+ specified in the "RRULE" property when the "DTSTART" property is
+ specified as a DATE value.
+
+ 4. The value type of the "DTEND" or "DUE" properties MUST match the
+ value type of "DTSTART" property.
+
+ 5. The "DURATION" property can no longer appear in "VFREEBUSY"
+ components.
+
+A.2. Restrictions Removed
+
+ 1. The "DTSTART" and "DTEND" properties are no longer required to be
+ specified as date with local time and time zone reference when
+ used with a recurrence rule.
+
+A.3. Deprecated Features
+
+ 1. The "EXRULE" property can no longer be specified in a component.
+
+ 2. The "THISANDPRIOR" value can no longer be used with the "RANGE"
+ parameter.
+
+ 3. The "PROCEDURE" value can no longer be used with the "ACTION"
+ property.
+
+ 4. The value type RECUR no longer allows multiple values to be
+ specified by a COMMA-separated list of values.
+
+ 5. x-name rule parts can no longer be specified in properties of
+ RECUR value type (e.g., "RRULE"). x-param can be used on RECUR
+ value type properties instead.
+
+
+
+
+
+Desruisseaux Standards Track [Page 167]
+
+RFC 5545 iCalendar September 2009
+
+
+Author's Address
+
+ Bernard Desruisseaux (editor)
+ Oracle Corporation
+ 600 blvd. de Maisonneuve West
+ Suite 1900
+ Montreal, QC H3A 3J2
+ CANADA
+
+ EMail: bernard.desruisseaux@oracle.com
+ URI: http://www.oracle.com/
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Desruisseaux Standards Track [Page 168]
+
(DIR) diff --git a/ics2tsv b/ics2tsv
@@ -10,7 +10,7 @@ function mdays(mon, year)
return (mon == 2) ? (28 + isleap(year)) : (30 + (mon + (mon > 7)) % 2)
}
-function maketime(tm,
+function timegm(tm,
sec, mon, day)
{
sec = tm["sec"] + tm["min"] * 60 + tm["hour"] * 3600
@@ -29,19 +29,7 @@ function maketime(tm,
return sec + (day - 719527) * 86400
}
-function ical_to_epoch(str, offset,
- tm)
-{
- tm["year"] = substr(str, 1, 4)
- tm["mon"] = substr(str, 5, 2)
- tm["mday"] = substr(str, 7, 2)
- tm["hour"] = substr(str, 10, 2)
- tm["min"] = substr(str, 12, 2)
- offset = (substr(str, 16, 1) == "Z" ? 0 : offset)
- return maketime(tm) - offset
-}
-
-function print_event(ev, fields,
+function print_vevent(ev, fields,
i)
{
for (i = 1; i in fields; i++)
@@ -49,44 +37,102 @@ function print_event(ev, fields,
printf("\n")
}
+function ical_parse_line(str, content, params,
+ i, eq)
+{
+ if ((i = index(str, ":")) == 0)
+ return -1
+ content["value"] = substr(str, i + 1)
+ str = substr(str, 1, i - 1)
+
+ if ((i = index(str, ";")) == 0) {
+ content["name"] = str
+ return 0
+ }
+ content["name"] = substr(str, 1, i - 1)
+ str = substr(str, i + 1)
+
+ while ((i = index(str, ";")) > 0) {
+ if ((eq = index(str, "=")) == 0)
+ return -1
+ param[substr(str, 1, eq - 1)] = substr(str, eq + 1, i - 1)
+ str = substr(str, eq + 1)
+ }
+ if ((eq = index(str, "=")) == 0)
+ return -1
+ params[substr(str, 1, eq - 1)] = substr(str, eq + 1)
+ return 0
+}
+
+function ical_to_epoch(content, param,
+ tz, cmd)
+{
+ tz = (param["TZID"] ? param["TZID"] : vcalendar["TZID"])
+ gsub("'", "", tz)
+
+ cmd = "TZ='"tz"' date +%z"
+ cmd | getline tz
+ close(cmd)
+
+ tz = substr(tz, 1, 1) substr(tz, 2, 2)*3600 + substr(tz, 4, 2)*60
+
+ tm["year"] = substr(content["value"], 1, 4)
+ tm["mon"] = substr(content["value"], 5, 2)
+ tm["mday"] = substr(content["value"], 8, 2)
+ tm["hour"] = substr(content["value"], 12, 2)
+ tm["min"] = substr(content["value"], 15, 2)
+ tm["sec"] = substr(content["value"], 18, 2)
+
+ return timegm(tm) + tz
+}
+
BEGIN {
- FIELDS = "DTSTART DTEND CATEGORIES LOCATION SUMMARY DESCRIPTION"
- split(FIELDS, fields, " ")
+ split("DTSTART DTEND CATEGORIES LOCATION SUMMARY DESCRIPTION",
+ FIELDS, " ")
+ DT["DTSTART"] = DT["DTEND"] = DT["DUE"] = 1
# by default: "CATEGORIES" -> "cat", "LOCATION" -> "loc"...
translate["DTSTART"] = "beg"
translate["DTEND"] = "end"
- "date +%z" | getline
- close("date +%z")
- TZ = substr($0, 3, 1) substr($0, 4, 2)*3600 + substr($0, 6, 2)*60
-
- FS = "[:;]"
-
- for (i = 1; i in fields; i++) {
- if (!(s = translate[fields[i]]))
- s = tolower(substr(fields[i], 1, 3))
+ for (i = 1; i in FIELDS; i++) {
+ if (!(s = translate[FIELDS[i]]))
+ s = tolower(substr(FIELDS[i], 1, 3))
printf("%s%s", (i > 1 ? "\t" : ""), s)
}
printf("\n")
+
+ FS = "[:;]"
}
{
gsub("\r", "")
+ gsub("\t", "\\\\t")
}
-/^ / {
- ev[type] = ev[type] substr($0, 2, length($0) - 1)
+sub("^ ", "") {
+ content["value"] = content["value"] $0
next
}
{
- i = index($0, ":")
- ev[$1] = substr($0, i + 1, length($0) - i)
+ delete content
+ delete param
+
+ if (ical_parse_line($0, content, params) < 0)
+ next
+
+ if (content["name"] == "TZID") {
+ vcalendar[content["name"]] = content["value"]
+ } else if (DT[content["name"]]) {
+ vevent[content["name"]] = ical_to_epoch(content, params)
+ } else {
+ vevent[content["name"]] = content["value"]
+ }
}
/^END:VEVENT/ {
- ev["DTSTART"] = ical_to_epoch(ev["DTSTART"], offset)
- ev["DTEND"] = ical_to_epoch(ev["DTEND"], offset)
- print_event(ev, fields)
+ print_vevent(vevent, FIELDS)
+ delete vevent
+ next
}