Network Working Group Frank Dawson, Lotus
Internet Draft Derik Stenerson, Microsoft
<ietf-calsch-ical-06.txt> March 13, 1998
Expires September 1998
Internet Calendaring and Scheduling Core Object Specification
(iCalendar)
Status of this Memo
This memo is an Internet-Draft. Internet-Drafts are working documents
of the Internet Engineering Task Force (IETF), its areas, and its
working groups. Note that other groups MAY also distribute working
documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months. Internet-Drafts MAY be updated, replaced, or made obsolete by
other documents at any time. It is not appropriate to use Internet-
Drafts as reference material or to cite them other than as a "working
draft" or "work in progress".
To learn the current status of any Internet-Draft, please check the
1id-abstracts.txt listing contained in the Internet-Drafts Shadow
Directories on ds.internic.net (US East Coast), nic.nordu.net
(Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific
Rim).
Distribution of this memo is unlimited.
Copyright (C) The Internet Society 1997. All Rights Reserved.
Abstract
There is a clear need to provide and deploy interoperable calendaring
and scheduling services for the Internet. Current group scheduling
and Personal Information Management (PIM) products are being extended
for use across the Internet, today, in proprietary ways. This memo
has been defined to provide the definition of a common format for
openly exchanging calendaring and scheduling information across the
Internet.
This memo is formatted as a registration for a MIME media type per
[RFC 2048]. However, the format in this memo is equally applicable
for use outside of a MIME message content type.
The proposed media type value is ''text/calendar''. This string would
label a media type containing calendaring and scheduling information
encoded as text characters formatted in a manner outlined below.
This MIME media type provides a standard content type for capturing
calendar event, to-do and journal entry information. It also can be
used to convey free/busy time information. The content type is
suitable as a MIME message entity that can be transferred over MIME
based email systems, using HTTP or some other Internet transport. In
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addition, the content type is useful as an object for interactions
between desktop applications using the operating system clipboard,
drag/drop or file systems capabilities.
This memo is based on the earlier work of the vCalendar specification
for the exchange of personal calendaring and scheduling information.
In order to avoid confusion with this referenced work, this memo is
to be known as the iCalendar specification.
Readers may also wish to refer to the calendaring and scheduling
model defined in [] for a description of this Internet application.
This memo defines the format for specifying iCalendar object methods.
An iCalendar object method is a set of usage constraints for the
iCalendar object. For example, these methods might define scheduling
messages that request an event be scheduled, reply to an event
request, send a cancellation notice for an event, modify or replace
the definition of an event, provide a counter proposal for an
original event request, delegate an event request to another
individual, request free or busy time, reply to a free or busy time
request, or provide similar scheduling messages for a to-do or
journal entry calendar component. The iCalendar Transport-indendent
Interoperability Protocol (iTIP) defined in [ITIP] is one such
scheduling protocol.
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Table of Contents
1 Introduction.........................................................8
2 Basic Grammar and Conventions........................................8
2.1 Formatting Conventions ...........................................9
2.2 Related Memos ...................................................10
3 TEXT/CALENDAR Registration Information..............................10
4 iCalendar Object Specification......................................13
4.1 Content Lines ...................................................13
4.1.1 List and Field Separators ....................................16
4.1.2 Multiple Values ..............................................16
4.1.3 Binary Content ...............................................17
4.1.4 Character Set ................................................17
4.2 Property Parameters .............................................17
4.2.1 Alternate Text Representation ................................18
4.2.2 Inline Encoding ..............................................19
4.2.3 Language .....................................................19
4.2.4 Time Zone Identifier .........................................20
4.2.5 Value Data Types .............................................21
4.3 Property Value Data Types .......................................21
4.3.1 Binary .......................................................22
4.3.2 Boolean ......................................................22
4.3.3 Calendar User Address ........................................23
4.3.4 Date .........................................................23
4.3.5 Date-Time ....................................................24
4.3.6 Duration .....................................................25
4.3.7 Float ........................................................26
4.3.8 Integer ......................................................27
4.3.9 Period of Time ...............................................27
4.3.10 Recurrence Rule .............................................28
4.3.11 Text ........................................................33
4.3.12 Time ........................................................34
4.3.13 URI .........................................................36
4.3.14 UTC Offset ..................................................36
4.4 iCalendar Object ................................................37
4.5 Property ........................................................38
4.6 Calendar Components .............................................38
4.6.1 Event Component ..............................................38
4.6.2 To-do Component ..............................................40
4.6.3 Journal Component ............................................41
4.6.4 Free/Busy Component ..........................................43
4.6.5 Timezone Component ...........................................45
4.6.6 Alarm Component ..............................................50
4.7 Calendar Properties .............................................53
4.7.1 Calendar Scale ...............................................54
4.7.2 Method .......................................................54
4.7.3 Product Identifier ...........................................55
4.7.4 Version ......................................................56
4.8 Component Properties ............................................56
4.8.1 Descriptive Component Properties .............................56
4.8.1.1 Attachment ...............................................56
4.8.1.2 Categories ...............................................57
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4.8.1.3 Classification ...........................................58
4.8.1.4 Comment ..................................................59
4.8.1.5 Description ..............................................59
4.8.1.6 Geographic Position ......................................60
4.8.1.7 Location .................................................61
4.8.1.8 Percent Complete .........................................61
4.8.1.9 Priority .................................................62
4.8.1.10 Resources ...............................................63
4.8.1.11 Status ..................................................64
4.8.1.12 Summary .................................................65
4.8.2 Date and Time Component Properties ...........................66
4.8.2.1 Date/Time Completed ......................................66
4.8.2.2 Date/Time End ............................................66
4.8.2.3 Date/Time Due ............................................67
4.8.2.4 Date/Time Start ..........................................68
4.8.2.5 Duration .................................................69
4.8.2.6 Free/Busy Time ...........................................69
4.8.2.7 Time Transparency ........................................71
4.8.3 Time Zone Component Properties ...............................72
4.8.3.1 Time Zone Identifier .....................................72
4.8.3.2 Time Zone Name ...........................................72
4.8.3.3 Time Zone Offset From ....................................73
4.8.3.4 Time Zone Offset To ......................................74
4.8.3.5 Time Zone URL ............................................74
4.8.4 Relationship Component Properties ............................75
4.8.4.1 Attendee .................................................75
4.8.4.2 Contact ..................................................78
4.8.4.3 Organizer ................................................79
4.8.4.4 Recurrence ID ............................................80
4.8.4.5 Related To ...............................................81
4.8.4.6 Uniform Resource Locator .................................82
4.8.4.7 Unique Identifier ........................................83
4.8.5 Recurrence Component Properties ..............................84
4.8.5.1 Exception Date/Times .....................................84
4.8.5.2 Exception Rule ...........................................85
4.8.5.3 Recurrence Date/Times ....................................86
4.8.5.4 Recurrence Rule ..........................................88
4.8.6 Alarm Component Properties ...................................95
4.8.6.1 Alarm Type ...............................................96
4.8.6.2 Repeat Count .............................................96
4.8.6.3 Trigger ..................................................97
4.8.7 Change Management Component Properties .......................98
4.8.7.1 Date/Time Created ........................................98
4.8.7.2 Date/Time Stamp ..........................................99
4.8.7.3 Last Modified ............................................99
4.8.7.4 Sequence Number .........................................100
4.8.8 Miscellaneous Component Properties ..........................101
4.8.8.1 Non-standard Properties .................................101
4.8.8.2 Request Status ..........................................102
5 iCalendar Object Examples..........................................103
6 Recommended Practices..............................................107
7 Registration of Content Type Elements..............................107
7.1 Registration of New and Modified iCalendar Object Methods ......107
7.2 Registration of New Properties .................................108
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7.2.1 Define the property .........................................108
7.2.2 Post the Property definition ................................109
7.2.3 Allow a comment period ......................................109
7.2.4 Submit the property for approval ............................109
7.3 Property Change Control ........................................109
8 References.........................................................109
9 Acknowledgments....................................................111
10 Author's Address..................................................111
11 Full Copyright Statement..........................................112
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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. However, the longer term growth of
calendaring and scheduling, is currently limited by the lack of
Internet standards for the message content types that are central to
these knowledgeware applications. 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 calendaring and scheduling model, defined in the [ICMS], is a
useful reference to terms and the general framework of this Internet
application.
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 might also be used.
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 a 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 [ITIP].
The memo also includes a formal grammar for the content type based on
the Internet ABNF defined in [RFC 2234]. 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.
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 interoperated as described in [RFC 2119].
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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 [RFC 2234].
Readers intending on implementing this format defined in this memo
should be familiar with this notation in order to properly interpret
the specifications of this memo.
All numeric and hexadecimal 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 that
is not essential to the building of a conformant implementation
of the specifications of this memo. The information is provided
to highlight a particular feature or characteristic of the
specifications.
The format for the iCalendar object is based on the syntax of the
[MIME DIR] content type. While the iCalendar object is not a profile
of the [MIME DIR] content type, it does reuse a number of the
elements from the [MIME DIR] specification.
2.1 Formatting Conventions
The mechanisms defined in this memo are defined in propose. 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 [ICMS],
core object (this memo) or interoperability protocol [ITIP] some
formatting conventions have been used. Calendaring and scheduling
roles defined by [ICMS] are referred to in quoted-strings of text
with the first character of each word in upper case. For example,
"Organizer" refers to a role of a "Calendar User" within the
scheduling protocol defined by [ITIP] Calendar components defined by
this memo are referred to 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] 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, "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 lower case, quoted-strings of text,
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followed by the word "parameter". For example, "value" parameter
refers to the iCalendar property parameter used to override the
default data 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" data type to specify
repeating components based on an interval of one minute or more.
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, [ICAL], specifies a core
specification of objects, data types, properties and property
parameters.
[ICMS] - specifies a common terminology and abstract model;
[ITIP] - specifies an interoperability protocol for scheduling
between different implementations;
[IMIP] specifies an Internet email binding for [ITIP];
[IRIP] - specifies an Internet real time protocol binding for [ITIP].
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 TEXT/CALENDAR Registration Information
The Calendaring and Scheduling Core Object Specification is intended
for use as a MIME content type. However, the implementation of the
memo is in no way limited solely as a MIME content type.
The following text is intended to register this memo as the MIME
content type "text/calendar".
To: ietf-types@uninett.no
Subject: Registration of MIME content type text/calendar.
MIME media type name: text
MIME subtype name: calendar
Required parameters: none
Optional parameters: charset, method and component
The "charset" parameter is defined in [RFC 2046] for other body
parts. It is used to identify the default character set used within
the body part.
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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 that the iCalendar object consists of. 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 MAY contain any set of
properties permitted by the Calendaring and Scheduling Core Object
Specification. The "method" parameter MUST be the same value as
that specified in the "METHOD" component property in the iCalendar
object. If one is present, the other must also be present.
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, then different components are
each specified once in a comma-separated list of values.
The value for the "component" parameter is defined as follows:
component = ("VEVENT" / "VTODO" / "VJOURNAL" / "VFREEBUSY"
/ "VTIMEZONE" / x-name / iana-token) ["," [WSP]
component]
Optional content header fields: Any header fields defined by [RFC
2045].
Encoding considerations: This MIME content type can contain 8bit
characters, so the use of quoted-printable or base64 MIME content-
transfer-encodings MAY be necessary when iCalendar objects are
transferred across protocols restricted to the 7bit repertoire.
Note that a text valued property in the content entity MAY also
have content encoding of special characters using a BACKSLASH
character (ASCII decimal 92) escapement technique. This means that
content values MAY end up encoded twice.
Security considerations: SPOOFING - - In this memo, the "Organizer"
is the only person authorized to make changes to an existing
"VEVENT", "VTODO", "VJOURNAL" calendar component and redistribute
the updates to the "Attendees". An iCalendar object that
maliciously changes or cancels an existing "VEVENT", "VTODO" or
"VJOURNAL" or "VFREEBUSY" calendar component MAY be constructed by
someone other than the "Organizer" and sent to the "Attendees". In
addition in this memo, other than the "Organizer", an "Attendee" of
a "VEVENT", "VTODO", "VJOURNAL" calendar component is the only
other person authorized to update any parameter associated with
their "ATTENDEE" property and send it to the "Organizer". An
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iCalendar object that maliciously changes the "ATTENDEE" parameters
MAY be constructed by someone other than the real "Attendee" and
sent to the "Organizer".
PROCEDURAL ALARMS - - An iCalendar object can be created that
contains a "VEVENT" and "VTODO" calendar component with an "VALARM"
calendar components. The "VALARM" calendar component MAY be of type
PROCEDURE and MAY have an attachment containing some sort of
executable program. Implementations that incorporate these types of
alarms are subject to any virus or malicious attack that MAY occur
as a result of executing the attachment.
ATTACHMENTS - - An iCalendar object MAY include references to
Uniform Resource Locators that MAY be programmed resources.
Implementers and users of this memo should be aware of the network
security implications of accepting and parsing such information. In
addition, the security considerations observed by implementations
of electronic mail systems should be followed for this memo.
Interoperability considerations: This MIME content 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.
Applications which use this media type: This content-type is
designed for widespread use by Internet calendaring and scheduling
applications. In addition, applications in the workflow and
document management area may find this content-type applicable. The
[ITIP], [IMIP] and [IRIP] Internet protocols directly use this
content-type also. Future work on an Internet calendar access
protocol will utilize this content-type too.
Additional information: This memo defines this content-type.
Magic numbers: None.
File extensions: 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 codes: 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 "ifb" 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.
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Person & email address to contact for further information:
Frank Dawson
6544 Battleford Drive
Raleigh, NC 27613-3502
919-676-9515 (Telephone)
919-676-9564 (Data/Facsimile)
Frank_Dawson@Lotus.com (Internet Mail)
Derik Stenerson
One Microsoft Way
Redmond, WA 98052-6399
425-936-5522 (Telephone)
425-936-7329 (Facsimile)
deriks@microsoft.com (Internet Mail)
Intended usage: COMMON
Author/change controller:
Frank Dawson
6544 Battleford Drive
Raleigh, NC 27613-3502
919-676-9515 (Telephone)
919-676-9564 (Data/Facsimile)
Frank_Dawson@Lotus.com (Internet Mail)
Derik Stenerson
One Microsoft Way
Redmond, WA 98052-6399
425-936-5522 (Telephone)
425-936-7329 (Facsimile)
deriks@microsoft.com (Internet Mail)
4 iCalendar Object Specification
The following sections define the details of a Calendaring and
Scheduling Core Object Specification. This information is intended to
be an integral part of the MIME content type registration. In
addition, this information MAY 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.
4.1 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 (ASCII decimal 13, followed by ASCII decimal
10).
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Lines of text SHOULD NOT be longer than 75 characters, 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 MAY be split at any point by inserting a CRLF immediately
followed by a single linear white space character (i.e., SPACE, ASCII
decimal 32 or HTAB, ASCII decimal 9). 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 character and the linear white
space character that immediately follows.
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 characters SHOULD be folded
according to the folding procedure described above.
The content information associated with an iCalendar object is
formatted using a syntax similar to that defined by [MIME DIR]. That
is, the content information consists of one or more CRLF-separated
content lines.
The following notation defines the defines the lines of content in an
iCalendar object:
contentline = name *(";" [WSP] 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 characters SHOULD be folded according to
; the folding procedure described above.
name = x-name / iana-token
iana-token = 1*(ALPHA / DIGIT / "-")
; iCalendar identifier registered with IANA
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x-name = "X-" 1*(ALPHA / DIGIT / "-")
; Reservered for experimental use. Not intended for use in
; released products.
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
param-value = paramtext / quoted-string
paramtext = *SAFE-CHAR
value = *VALUE-CHAR
quoted-string = DQUOTE *qtext DQUOTE
qtext = QSAFE-CHAR / QUOTED-CHAR
NON-ASCII = %x80-FF
; Use restricted by charset parameter
; on outer MIME object (UTF-8 preferred)
QSAFE-CHAR = WSP / %x21 / %x23-5B / %x5D-7E / NON-ASCII
; Any character except CTLs, DQUOTE, or "\"
QUOTED-CHAR = "\" ("\" / "," / DQUOTE)
; \\ encodes \, \" encodes "
SAFE-CHAR = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-7E
/ NON-ASCII
; Any character except CTLs, DQUOTE, ";", ":", ","
VALUE-CHAR = WSP / VCHAR / NON-ASCII
; Any textual character
VCHAR = %x21-7E
; visible (printing) characters
CR = %x0D
; carriage return
LF = %x0A
CRLF = CR LF
; Internet standard newline
CTL = %x00-1F / %x7F
; Controls
ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
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DIGIT = %x30-39
; 0-9
DQUOTE = %x22
; Quotation Mark
WSP = SPACE / HTAB
SPACE = %x20
HTAB = %x09
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.
4.1.1 List and Field Separators
List of values MAY be specified for property values or property
parameter values. Each value in a list of values MUST be separated by
a COMMA character (ASCII decimal 44).
Some property values are defined in terms of multiple components.
These structured property values MUST have their components separated
by a SEMICOLON character (ASCII decimal 59).
Lists of property parameters MAY be specified for a property. Each
property parameter in a list of property parameters MUST be separated
by a SEMICOLON character (ASCII decimal 59).
Property parameters with values containing a COLON, a SEMICOLON or a
COMMA character must be placed in quoted text string.
For example, in the following properties a SEMICOLON is used to
separate property parameters and property value fields. A COMMA is
used to separate values.
ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT:MAILTO:
jsmith@host.com
RDATE;VALUE=DATE:19970304,19970504,19970704,19970904
4.1.2 Multiple Values
Some properties defined in the iCalendar object MAY 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 (ASCII decimal 44).
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4.1.3 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
MAY be included within an iCalendar object, but only after first
encoding it into text using the "B" encoding method defined in [RFC
2047]. Support for inline binary content SHOULD be restricted to
those applications requirements that necessitate conveying the
complete calendaring and scheduling information within a single
iCalendar object. 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://xyz.com/public/quarterly-report.doc
The following example specifies an "ATTACH" property with inline
binary encoded content information:
ATTACH;ENCODING=b;VALUE=binary:MIICajCCAdOgAwIBAgICBEUwDQYJKoZI
hvcNAQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENv
bW11bmljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZvcm1hdGlv
biBTeXN0 <...remainder of "B" encoded binary data...>
4.1.4 Character Set
There is not a property parameter to declare the character set used
in a property value. The default character set for an iCalendar
object is [UTF-8].
The "charset" Content-Type parameter MAY be used in MIME transports
to specify any other IANA registered character set.
4.2 Property Parameters
A property MAY have additional attributes associated with it. These
"property parameters" contain meta information about the property or
the property value. Property parameters MAY be used to specify the
location of an alternate text representation for a property value,
the language of a text property value or the data type of the
property value. In addition, individual properties MAY define
property-specific parameters that apply only to that property.
Property parameter values that contain the COLON, SEMICOLON, COMMA or
BACKSLASH character separators MUST be specified as quoted-string
text values. For example:
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DESCRIPTION;ALTREP="http://www.wiz.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 specified
the following notation:
parameter = altrepparm ;Alternate text representation
/ encodingparm ;Inline encoding
/ languageparm ;National language for text
/ tzidparm ;Reference to time zone object
/ valuetypeparm ;Property value data type
/ iana-token
;Some other IANA registered iCalendar parameter, such as those
;defined by an individual property.
/ x-name
;A non-standard, experimental parameter
4.2.1 Alternate Text Representation
Parameter Name: ALTREP
Purpose: To specify an alternate text representation for the property
value.
Conformance: Optional
Format Definition: The property parameter is defined by the following
notation:
altrepparm = "altrep" "=" DQUOTE uri DQUOTE
Description: The 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 the
default representation.
This property parameter MAY include multiple values, separated by the
COMMA character (ASCII decimal 44). The property parameter MAY only
be specified in the "COMMENT", "CONTACT", "DESCRIPTION", "LOCATION"
and "SUMMARY" properties.
Example:
DESCRIPTION;ALTREP="CID:<part3.msg.970415T083000@host.com>":Project
XYZ Review Meeting will include the following agenda items: (a)
Market Overview, (b) Finances, (c) Project Management
The "ALTREP" property parameter value might point to a "text/html"
content portion.
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Content-Type:text/html
Content-Id:<part3.msg.970415T083000@host.com>
<p><b>Project XYZ Review Meeting</b> will include the following
agenda items:<li>Market
Overview</li><li>Finances</li><li>Project Management</li></p>
4.2.2 Inline Encoding
Parameter Name: ENCODING
Purpose: To specify an alternate inline encoding for the property
value.
Conformance: Required, if the inline encoding is not "8bit".
Format Definition: The property parameter is defined by the following
notation:
encodingparm = "encoding" "=" "8bit"
;"8bit" text encoding is defined in [RFC 2045]
/ "b"
;"b" binary encoding format is defined in [RFC 2047]
/ iana-token
;Some other IANA registered iCalendar encoding type
/ x-name
;A non-standard, experimental encoding type
Description: The "ENCODING property parameter is an OPTIONAL property
parameter. It identifies the inline encoding used in a property
value. The default encoding type is "8bit", corresponding to a
property value consisting of text. The "b" encoding type corresponds
to a property value encoded using the "B" encoding defined in [RFC
2047].
If the value type parameter is ";VALUE=BINARY", then the inline
encoding parameter MUST be specified with the value ";ENCODING=B".
4.2.3 Language
Parameter Name: LANGUAGE
Purpose: To specify the national language for text values in a
property or property parameter.
Conformance: Optional. There is no default national language for a
text value.
Format Definition: The property parameter is defined by the following
notation:
languageparm = "language" "=" language
language = <Text identifying a language, as defined in [RFC 1766]>
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Description: The parameter identifies the national language of the
text in the property or property parameter value. The value of the
"language" property parameter is that defined in [RFC 1766].
Note: For transport in a MIME entity, the Content-Language
header field MAY be used to set the default language for the
entire body part.
Example:
SUMMARY;LANGUAGE=us-EN:Company Holiday Party
ATTENDEE;CN=Henri Weisz;LANGUAGE=ca-FR:hweisz@host.com
4.2.4 Time Zone Identifier
Parameter Name: TZID
Purpose: To specify the identifier for the time zone definition for a
time value.
Conformance: Optional
Format Definition: This property parameter is defined by the
following notation:
tzidparm = "TZID" "=" [tzidprefix] paramtext CRLF
tzidprefix = "/"
Description: The parameter MAY only be used on the "DTSTART",
"DTEND", "DUE", "EXDATE" and "RDATE " properties when either a DATE-
TIME or TIME value type is specified. This property parameter
specifies a text value which uniquely identifies the "VTIMEZONE"
calendar component to be used when evalating 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 "TIMEZONE" object.
The presence of the SOLIDUS character (ASCII decimal 47) as a prefix,
indicates that this TZID represents a unique ID in a globally defined
time zone registry (when such registry is defined).
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-TIME nor 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 a local time value,
regardless of the existence of "VTIMEZONE" calendar components in the
iCalendar object.
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For more information see the sections on the data types DATE-TIME and
TIME.
4.2.5 Value Data Types
Parameter Name: VALUE
Purpose: To explicitly specify the data type format for a property
value.
Conformance: Optional if using the default value type in a property
value. Otherwise, it is required.
Format Definition: The "VALUE" property parameter is defined by the
following notation:
valuetypeparm = "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 data type.
/ iana-token
;Some other IANA registered iCalendar data type.
Description: The parameter is used to identify the data 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.
4.3 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.
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4.3.1 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 an object code MAY BE included in an iCalendar object.
Formal Definition: The value type is defined by the following
notation:
binary = *(4b-char) [b-end]
; A "B" encoded character string, as defined by [RFC 2047].
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=B". That is, all
inline binary data MUST first be character encoded using the "B"
encoding method defined in [RFC 2047]. No additional content value
encoding (i.e., BACKSLASH character encoding) is defined for this
value type.
Example: The following is an abridged example of a "B" encoded binary
value data.
ATTACH;VALUE=BINARY:MIICajCCAdOgAwIBAgICBEUwDQYJKoZIhvcNAQEEBQA
wdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENvbW11bmljYXRpb
25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZvcm1hdGlvbiBTeXN0
<...remainder of "B" encoded binary data...>
4.3.2 Boolean
Value Name: BOOLEAN
Purpose: This value type is used to identify properties that contain
either a "true" or "false" boolean value.
Formal Definition: The value type is defind by the following
notation:
boolean = "TRUE" / "FALSE"
Description: These values are case insensitive text. No additional
content value encoding (i.e., BACKSLASH character encoding) is
defined for this value type.
Example: For example, any of the following are equivalent:
TRANSP;VALUE=BOOLEAN:TRUE
TRANSP;VALUE=BOOLEAN:true
TRANSP;VALUE=BOOLEAN:TrUe
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4.3.3 Calendar User Address
Value Name: CAL-ADDRESS
Purpose: This value type is used to identify properties that contain
a calendar user address.
Formal Definition: The value type is as defined by the following
notation:
cal-address = uri
Description: The value is a URI as defined by [RFC 1738] or any other
IANA registered form for a URI. When used to address an Internet
email transport address for a calendar user, the value MUST be a
MAILTO URI, as defined by [RFC 1738].No additional content value
encoding (i.e., BACKSLASH character encoding) is defined for this
value type.
Example:
ATTENDEE;VALUE=CAL-ADDRESS:MAILTO:jane_doe@host.com
4.3.4 Date
Value Name: DATE
Purpose: This value type is used to identify values that contain a
calendar date.
Formal Definition: The value type is defined by the following
notation:
date = date-value *("," [WSP] 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 MAY be
specified using a COMMA character (ASCII decimal 44) separator
character.The format for the value type is expressed as the [ISO
8601] 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) is defined for this value type.
Example: The following represents July 14, 1997:
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19970714
4.3.5 Date-Time
Value Name: DATE-TIME
Purpose: This value type is used to identify values that specify a
precise calendar data and time of day.
Formal Definition: The value type is defined by the following
notation:
date-time = dt-value *("," [WSP] dt-value)
dt-value = date "T" time ;As specified above in date and time
Description: If the property permits, multiple "date-time" values MAY
be specified using a COMMA character (ASCII decimal 44) separator
character. No additional content value encoding (i.e., BACKSLASH
character encoding) is defined for this value type.
The "DATE-TIME" data type is used to identify values that contain a
precise calendar date and time of day. The format is based on the
[ISO 8601] 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 (ASCII decimal 84)
time designator, followed by the "time" format.
The "DATE-TIME" data 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:
DTSTART:19980119T230000-0800
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 Janurary 18, 1998, at 11 PM:
DTSTART: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 MAY be defined that
indicates that an individual will be busy from 11:00 AM to 1:00 PM
every day, no matter which timezone the person is in. In these cases,
a local time MAY 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 timezone the ATTENDEE is in at any given moment.
This means that two ATTENDEEs may participate in the same event at
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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 DATE-TIME value without the TZID property
parameter is to be interpreted as a local time value, 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 (ASCII decimal 90), the UTC
designator, appended to the time value. For example, the following
represents January 19, 1998, at 0700 UTC:
DTSTART: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 the
section on Time Zone. For example, the following represents 2 AM in
New York on Janurary 19, 1998:
DTSTART;TZID=America-New_York:19980119T020000
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:19970714T153000Z ;UTC time
DTSTART;TZID=America-NYC:19970714T133000 ;Local time and time
; zone reference
4.3.6 Duration
Value Name: DURATION
Purpose: This value type is used to identify properties that contain
a duration of time.
Formal Definition: The value type is defined by the following
notation:
duration = dur-value *("," [WSP] dur-value)
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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 MAY
be specified using a COMMA character (ASCII decimal 44) separator
character.The format is expressed as the [ISO 8601] basic format for
the duration of time. The format can represent durations in terms of
years, months, days, hours, minutes, and seconds.
No additional content value encoding (i.e., BACKSLASH character
encoding) are defined for this value type.
Example: A duration of 15 days, 5 hours, 30 minutes and 20 seconds
would be:
P15DT5H30M20S
A duration of 7 weeks would be:
P15DT5H30M20S
4.3.7 Float
Value Name: FLOAT
Purpose: This value type is used to identify properties that contain
a real value number value.
Formal Definition: The value type is defined by the following
notation:
float = float-value *("," [WSP] float-value)
float-value = (["+"] / "-") 1*DIGIT ["." 1*DIGIT]
Description: If the property permits, multiple "float" values MAY be
specified using a COMMA character (ASCII decimal 44) separator
character.
No additional content value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.
Example:
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1000000.0000001
1.333
-3.14
4.3.8 Integer
Value Name:INTEGER
Purpose: This value type is used to identify properties that contain
a signed integer value.
Formal Definition: The value type is defined by the following
notation:
integer = integer-value *("," [WSP] integer-value)
integer-value = (["+"] / "-") *DIGIT
Description: If the property permits, multiple "integer" values MAY
be specified using a COMMA character (ASCII decimal 44) separator
character.The valid range for "integer" is -2147483648 to 2147483647.
If the sign is not specified, then the value is assumed to be
positive. If the property permits, multiple "integer" values MAY be
specified using a COMMA character (ASCII decimal 44) separator
character.
No additional content value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.
Example:
1234567890
-1234567890
+1234567890
432109876
4.3.9 Period of Time
Value Name: PERIOD
Purpose: This value type is used to identify values that contain a
precise period of time.
Formal Definition: The data type is defined by the following
notation:
period = period-value *("," [WSP] period-value)
period-value = period-explicit / period-start
period-explicit = date-time "/" date-time
;ISO 8601 complete representation basic format for a period of time
;consisting of a start and end. The start MUST be before the end.
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period-start = date-time "/" duration
;ISO 8601 complete representation basic format for a period of time
;consisting of a start and duration of time.
Description: If the property permits, multiple "period" values MAY be
specified using a COMMA character (ASCII decimal 44) separator
character. There are two forms of a period of time. A period of time
MAY be identified by it's start and it's end. This format is
expressed as the [ISO 8601] complete representation, basic format for
"DATE-TIME" start of the period, followed by a SOLIDUS character
(ASCII decimal 47), followed by the "DATE-TIME" of the end of the
period. A period of time MAY also be defined by a start and a
duration of time. The format is expressed as the [ISO 8601] complete
representation, basic format for the "DATE-TIME" start of the period,
followed by a SOLIDUS character (ASCII decimal 47), followed by the
[ISO 8601] 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) is defined for this value type.
4.3.10 Recurrence Rule
Value Name: RECURR
Purpose: This value type is used to identify properties that contain
a recurrence rule specification.
Formal Definition: The value type is defined by the following
notation:
recur = recur-value *("," [WSP] recur-value)
recur-value = "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 ";"]
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["WKST" "=" weekday ";")]
*(x-name "=" text) ";"
;Individual components MAY only be specified once.
;Rule components need not be specified in particular any order.
freq = "SECONDLY" / "MINUTELY" / "HOURLY" / "DAILY"
/ "WEEKLY" / "MONTHLY" / "YEARLY"
enddate = date
enddate =/ date-time ;A UTC value
byseclist = seconds / ( seconds *("," seconds) )
seconds = 1DIGIT / 2DIGIT ;0 to 59
byminlist = minutes / ( minutes *("," minutes) )
minutes = 1DIGIT / 2DIGIT ;0 to 59
byhrlist = hour / ( hour *("," hour) )
hour = 1DIGIT / 2DIGIT ;0 to 23
bywdaylist = weekdaynum / ( weekdaynum *("," weekdaynum) )
weekdaynum = [([plus] ordwk / minus ordwk)] weekday
plus = "+"
minus = "-"
ordwk = 1DIGIT / 2DIGIT ;1 to 53
weekday = "SU" / "MO" / "TU" / "WE" / "TH" / "FR" / "SA"
;Corresponding to SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY,
;FRIDAY, SATURDAY and SUNDAY days of the week.
bymodaylist = monthdaynum / ( monthdaynum *("," monthdaynum) )
monthdaynum = ([plus] ordmoday) / (minus ordmoday)
ordmoday = 1DIGIT / 2DIGIT ;1 to 31
byyrdaylist = yeardaynum / ( yeardaynum *("," yeardaynum) )
yeardaynum = ([plus] ordyrday) / (minus ordyrday)
ordyrday = 1DIGIT / 2DIGIT / 3DIGIT ;1 to 366
bywknolist = weeknum / ( weeknum *("," weeknum) )
weeknum = ([plus] ordwk) / (minus ordwk)
bymolist = monthnum / ( monthnum *("," monthnum) )
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monthnum = 1DIGIT / 2DIGIT ;1 to 12
bysplist = setposday / ( setposday *("," setposday) )
setposday = yeardaynum
Description: If the property permits, multiple "recur" values MAY be
specified using a COMMA character (ASCII decimal 44) separator
character. The value type is a structured value consisting of a list
of one or more recurrence grammar components. Each component is
defined by a NAME=VALUE pair. The components are separated from each
other by the SEMICOLON character (ASCII decimal 59). The components
are not ordered in any particular sequence. Individual components MAY
only be specified once.
The FREQ component identifies the type of recurrence rule. This
component 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.
The INTERVAL component contains a positive integer representing how
often the recurrence rule repeats. The default value is "1" or every
minute for a MINUTELY rule, every hour for a 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.
The UNTIL component defines a date-time value which bounds the
recurrence rule in an inclusive manner. If the value specified by
UNTIL is synchronized with the specified recurrence, this date-time
becomes the last instance of the recurrence. If not present, and the
COUNT component is also not present, the RRULE is considered to
repeat forever.
The COUNT component defines the number of occurrences at which to
range-bound the recurrence. This component is ignored if the "UNTIL"
component is also present.
The BYSECOND component specifies a COMMA character (ASCII decimal 44)
separated list of seconds within a minute. Valid values are 0 to 59.
The BYMINUTE component specifies a COMMA character (ASCII decimal 44)
separated list of minutes within an hour. Valid values are 0 to 59.
The BYHOUR component specifies a COMMA character (ASCII decimal 44)
separated list of hours of the day. Valid values are 0 to 23.
The BYDAY component specifies a COMMA character (ASCII decimal 44)
separated list of days of the week; MO, indicates Monday; TU,
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indicates Tuesday; WE, indicates Wednesday; TH, indicates Thursday;
FR, indicates Friday; SA, indicates Saturday; SU, indicates Sunday.
Each BYDAY value MAY also be preceded by a positive (+n) or negative
(-n) integer. If present, this indicates the nth occurrence of the
specific day within the MONTHLY or YEARLY RRULE. 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. 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 BYMONTHDAY component specifies a COMMA character (ASCII decimal
44) separated list of days of the month. Valid values are 1 to 31 or
-31 to -1.
Each BYMONTHDAY value MAY include a positive (+n) or negative (-n)
integer. If present, this indicates the nth occurrence of the
specific day of the month within the MONTHLY rule. If an integer
modifier is not present, it means all days of this type within the
specified frequency. For example, within a MONTHLY rule, -10
represents the tenth to the last day of the month.
The BYYEARDAY component specifies a COMMA character (ASCII decimal
44) 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).
The BYWEEKNO component specifies a comma-separated list of weeks of
the year. Valid values are 1 to 53. This corresponds to weeks
according to week numbering as defined in [ISO 8601]. That is, a week
as "A seven day period within a calendar year, starting on a Monday
and identified by its ordinal number within the year; the first
calendar week of the year is the one that includes the first Thursday
of that year." This component is only valid for YEARLY rules.
Each BYWEEKNO value MAY include a positive (+n) or negative (-n)
integer. If present, this indicates the nth occurrence of the
specific week of the year within the YEARLY rule. If an integer
modifier is not present, it means all days of this type within the
specified frequency. For example, within a YEARLY rule, 3 represents
the third week of the year.
The BYMONTH component specifies a comma separated list of months of
the year. Valid values are 1 to 12.
The WKST component specifies the day on which the workweek starts.
Valid values are MO, TU, WE, TH, FR, SA and SU. This is significant
when a WEEKLY RRULE has an interval greater than 1, and a BYDAY
component is specified. The default value is MO.
The BYSETPOS component specifies a COMMA character (ASCII decimal 44)
separated list of values which corresponds to the nth occurrence
within the set of events specified by the rule. Valid values are 1 to
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366 or -366 to -1. It MUST only be used in conjunction with another
Byxxx component. For example "the last work day of the month" could
be represented as:
RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-1
Each BYSETPOS value MAY include a positive (+n) or negative (-n)
integer. If present, this indicates the nth occurrence of the
specific occurrence within the set of events specified by the rule.
If BYxxx component values are found which are beyond the available
scope (ie, BYMONTHDAY=30 in February), they are simply ignored.
Information, not contained in the rule, necessary to determine the
various recurrence instance start time and dates are derived from the
Start Time (DTSTART) entry 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 components modify the recurrence in some manner. BYxxx
components for a period of time which 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 tag is not
present) to all days in January. BYxxx components 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 tag is not present) to 2.
If only one BYxxx component is specified in the recurrence rule, the
list of "n" unique values would cause "n" occurrences of the
recurrence within each specified frequency interval, where each
unique list value is substituted in the appropriate date position
within DTSTART for each such occurrence.
If multiple BYxxx components are specified, then after evaluating the
specified FREQ and INTERVAL components, the BYxxx components are
applied to the current set of evaluated occurrences in the following
order: BYMONTH, BYWEEKNO, BYYEARDAY, BYMONTHDAY, BYDAY, BYHOUR,
BYMINUTE, BYSECOND and BYSETPOS.
Here is an example of evaluating multiple BYxxx components.
DTSTART;TZID=EST=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
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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". Similarly, if the BYMINUTE, BYHOUR,
BYDAY, BYMONTHDAY or BYMONTH component were missing, the appropriate
minute, hour, day or month would have been retrieved from the
"DTSTART" property.
No additional content value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.
Example: The following is a rule which specifies 10 meetings which
occur every other day:
FREQ=DAILY;COUNT=10;INTERVAL=2
There are other examples specified in the "RRULE" specification.
4.3.11 Text
Value Name: TEXT
Purpose This value type is used to identify values that contain human
readable text.
Formal Definition: The value type is defined by the following
notation:
text = text-value *("," text-value)
; Folded according to folded-value syntax above or
; encoded according to param-value syntax above.
text-value = *(SAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR)
ESCAPED-CHAR = "\\" / "\;" / "\," / "\N" / "\n")
; \\ encodes \, \N or \n encodes newline
; \; encodes ;, \, encodes ,
NON-ASCII = %x80-FF
; use restricted by charset parameter
; on outer MIME object
SAFE-CHAR = %x20-21 / %x23-2B / %x2D-39 / %x3C-5B
%x5D-7E / NON-ASCII
; Any character except CTLs, DQUOTE, ";", ":", "\", ","
Description: If the property permits, multiple "text" values MAY be
specified using a COMMA character (ASCII decimal 44) separator
character. The character set and language in which the text is
represented is controlled by the "LANGUAGE" property parameters.
An intentional formatted text line break MAY only be included in a
"TEXT" property value by representing the line break with the
character sequence of BACKSLASH (ASCII decimal 92), followed by a
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LATIN SMALL LETTER N (ASCII decimal 110) or a LATIN CAPITAL LETTER N
(ASCII decimal 78), 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 need to be escaped with a BACKSLASH character. A
BACKSLASH character (ASCII decimal 92) 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
(ASCII decimal 92). A SEMICOLON character in a "TEXT" property value
MUST be escaped with a BACKSLASH character (ASCII decimal 92).
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\n Conference Room - 3B\nCome Prepared.
4.3.12 Time
Value Name: TIME
Purpose: This value type is used to identify values that contain a
time of day.
Formal Definition: The data type is defined by the following
notation:
time = time-value *("," [WSP] time-value)
time-value = 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 years with "leap" seconds.
time-utc = "Z"
Description: If the property permits, multiple "time" values MAY be
specified using a COMMA character (ASCII decimal 44) separator
character. No additional content value encoding (i.e., BACKSLASH
character encoding) is defined for this value type.
The "TIME" data type is used to identify values that contain a time
of day. The format is based on the [ISO 8601] complete
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representation, basic format for a time of day. The text format
consists of a two-digit 24-hour of the day (i.e., values 0-23), two-
digit minute in the hour (i.e., values 0-59), and two-digit seconds
in the minute (i.e., values 0-59). Fractions of a second are not
supported by this format.
In parallel to the "DATE-TIME" definition above, the "TIME" data type
expresses time values in three forms:
Note: The form of time with UTC offset MUST NOT be used. For example,
the following is NOT VALID for a time value:
230000-0800
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 PM:
230000
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 MAY be defined that
indicates that an individual will be busy from 11:00 AM to 1:00 PM
every day, no matter which timezone the person is in. In these cases,
a local time MAY 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 timezone 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 a local time value, regardless of
the existence of "VTIMEZONE" calendar components in the iCalendar
object.
FORM #2: DATE WITH UTC TIME
UTC time, or absolute time, is identified by a LATIN CAPITAL LETTER Z
suffix character (ASCII decimal 90), the UTC designator, appended to
the time value. For example, the following represents 0700 UTC:
070000Z
The TZID property parameter MUST NOT be applied to TIME properties
whose time values are specified in UTC.
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FORM #3: DATE WITH 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 the
section on Time Zone.
Example: The following represents 8:30 AM in New York, five hours
behind UTC, in each of the three formats using the "DTSTART"
property:
DTSTART:19980312T083000
DTSTART:19980312T133000Z
DTSTART;TZID=America-New York:19980312T083000
4.3.13 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.
Formal Definition: The data type is defined by the following
notation:
uri = <As defined by any IETF RFC>
Description: This data type might be used to reference binary
information, for values that are large, or otherwise undesirable to
include directly in the iCalendar object.
The URI value formats in RFC 1738, RFC 2111 and any other IETF
registered value format MAY be specified.
Any IANA registered URI format MAY be used. These include, but are
not limited to, those defined in RFC 1738 and RFC 2111.
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) is defined for this value type.
Example: The following is a URI for a network file:
http://host1.com/my-report.txt
4.3.14 UTC Offset
Value Name: UTC-OFFSET
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Purpose: This value type is used to identify properties that contain
an offset from UTC to local time.
Formal Definition: The data type is defined by the following
notation:
utc-offset = time-numzone ;As defined above in time data
type
Description:
The PLUS SIGN character MUST be specified for positive UTC offsets.
No additional content value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.
Example: The following are UTC offsets are given for standard time
for New York (five hours behind UTC) and Geneva (one hour ahead of
UTC):
-0500
+0100
4.4 iCalendar Object
The Calendaring and Scheduling Core Object is a collection of
calendaring and scheduling information. Typically, this information
will consist of a single iCalendar object. However, multiple
iCalendar objects MAY be sequentially grouped together. The first
line and last line of the iCalendar object MUST contain a pair of
iCalendar object delimiter strings. The syntax for an iCalendar
object is as follows:
icalobject = "BEGIN" ":" [WSP] "VCALENDAR" CRLF
icalbody
"END" ":" [WSP] "VCALENDAR" CRLF [icalobject]
The following is a simple example of an iCalendar object:
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//hacksw/handcal//NONSGML v1.0//EN
BEGIN:VEVENT
DTSTART:19970714T170000Z
DTEND:19970715T045959Z
SUMMARY:Bastille Day Party
END:VEVENT
END:VCALENDAR
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4.5 Property
A property is the definition of an individual attribute describing a
calendar property or a calendar component. A property takes the form
defined by the "contentline" notation defined in section 4.1.1.
The following is an example of a property:
DTSTART:19960415T133000Z
This memo places no imposed ordering of properties within an
iCalendar object.
Property names, parameter names and parameter values (i.e.,
everything to the left of the ":" on a line) are case insensitive.
For example, the property name "DUE" is the same as "due" and "Due".
4.6 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 as a whole. The
calendar components are collections of properties that express a
particular calendar semantic. For example, the calendar component MAY
specify an event, a to-do, a journal entry, time zone information, or
free/busy time information, or an alarm.
The body of the iCalenar object is defined by the following notation:
icalbody = calprops 1*component
calprops = [calscale] [method] prodid version
component = 1*(eventc / todoc / journalc / freebusyc /
/ timezonec / x-name / iana-token)
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 is possible that is used to
capture a complete snapshot of the contents of a calendar (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.
4.6.1 Event Component
Component Name: "VEVENT"
Purpose: Provide a grouping of component properties that describe an
event.
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Format Definition: A "VEVENT" calendar component is defined by the
following notation:
eventc = "BEGIN" ":" [WSP] "VEVENT" CRLF
eventprop *alarmc
"END" ":" [WSP] "VEVENT" CRLF
eventprop = *attach *attendee *categories [class] *comment
*contact [created] [description] [dtend / duration]
dtstart *exdate *exrule [geo] [last-mod] [location]
[organizer] [priority] [rstatus] *related *resources
*rdate *rrule dtstamp [seq] [status] summary
[transp] uid [url] [recurid]
Description: A "VEVENT" calendar component is a grouping of component
properties and an OPTIONAL "VALARM" calendar component that represent
a scheduled amount of time on a calendar. For example, it MAY be an
activity; such as a one-hour, department meeting from 8:00 AM to 9:00
AM, tomorrow. Generally, these events 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 MAY have
its Time Transparency 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" and "DTEND" properties instead of
the default data type of DATE-TIME. If such a "VEVENT" has an end
time, it MUST be specified as a DATE value also. The anniversary type
of "VEVENT" MAY span more than one date (i.e, "DTEND" property value
is set to a calendar date after the "DTSTART" property 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 data type but no "DTEND" property, the events
non-inclusive end is the end of the calendar date specified by the
"DTSTART" property. For cases where a "VEVENT" calendar component
specifies a "DTSTART" property with a DATE-TIME data 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 MUST include the "DTSTAMP",
"DTSTART", "SUMMARY" and "UID" properties. In addition, it MUST
include the "SEQUENCE" property, if it's value is greater than zero.
The "VEVENT" calendar component cannot be nested within another
calendar component. The "VEVENT" calendar components MAY be related
to each other or to a "VTODO" or "VJOURNAL" calendar component with
the "RELATED-TO" property.
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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@host.com
DTSTAMP:19970901T1300Z
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:
BEGIN:VEVENT
UID:19970901T130000Z-123402@host.com
DTSTAMP:19970901T1300Z
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. Since it takes
up no time, it will not appear as opaque in a search for busy time;
no matter what the value of the "TRANSP" property indicates:
BEGIN:VEVENT
UID:19970901T130000Z-123403@host.com
DTSTAMP:19970901T1300Z
DTSTART:19971102
SUMMARY:Our Blissful Anniversary
CLASS:CONFIDENTIAL
CATEGORIES:ANNIVERSARY,PERSONAL,SPECIAL OCCASION
RRULE:FREQ=YEARLY
END:VEVENT
4.6.2 To-do Component
Component Name: VTODO
Purpose: Provide a grouping of calendar properties that describe a
to-do.
Formal Definition: A "VTODO" calendar component is defined by the
following notation:
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todoc = "BEGIN" ":" [WSP] "VTODO" CRLF
todoprop *alarmc
"END" ":" [WSP] "VTODO" CRLF
todoprop = *attach *attendee *categories [class] *comment
[completed] *contact [created] [description] dtstamp
[dtstart] [due / duration] *exdate *exrule [geo]
[last-mod] [location] [organizer] [percent] priority
[rstatus] *related *resources *rdate *rrule
[recurid] [seq] [status] summary uid [url]
Description: A "VTODO" calendar component is a grouping of component
properties and an OPTIONAL "VALARM" calendar component that represent
an action-item or assignment. For example, it MAY be an item of work
assigned to an individual; such as "turn in travel expense today".
The "VTODO" calendar component MUST include the "DTSTAMP",
"PRIORITY", "SUMMARY" and "UID" properties. In addition, it MUST
include the "SEQUENCE" property, if it's value is greater than zero.
The "VTODO" calendar component cannot be nested within another
calendar component. If "VTODO" calendar components need to be related
to each other or to a "VTODO" or "VJOURNAL" calendar component, they
can specify a relationship with the "RELATED-TO" property.
A "VTODO" calendar component without the "DTSTART" and "DUE" (or
"DURATION") properties specifies a to-do that is associated with each
successive calendar dates, until it is completed.
Example: The following is an example of a "VTODO" calendar component:
BEGIN:VTODO
UID:19970901T130000Z-123404@host.com
DTSTAMP:19970901T1300Z
DTSTART:19970415T133000Z
DUE:19970416T045959Z
SUMMARY:1996 Income Tax Preparation
CLASS:CONFIDENTIAL
CATEGORIES:FAMILY,FINANCE
PRIORITY:1
STATUS:NEEDS-ACTION
END:VEVENT
4.6.3 Journal Component
Component Name: VJOURNAL
Purpose: Provide a grouping of component properties that describe a
journal entry.
Formal Definition: A "VJOURNAL" calendar component is defined by the
following notation:
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journalc = "BEGIN" ":" [WSP] "VJOURNAL" CRLF
jourprop
"END" ":" [WSP] "VJOURNAL" CRLF
jourprop = *attach *attendee *categories [class] *comment
*contact [created] description dtstart dtstamp
*exdate *exrule [last-mod] [organizer] [recurid]
*related *rdate *rrule [rstatus] [seq] summary
uid [url]
Description: A "VJOURNAL" calendar component is a grouping of
component properties that represent one or more descriptive text
notes on a particular calendar date. The "DTSTART" property is used
to specify the calendar date that the journal entry is associated
with. Generally, it will have a DATE value data type, but it MAY 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.
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 MUST include the "DTSTAMP",
"DTSTART", "DESCRIPTION", "SUMMARY" an "UID" properties. In addition,
it MUST include the "SEQUENCE" property, if it's value is greater
than zero.
The "VJOURNAL" calendar component cannot be nested within another
calendar component. If "VJOURNAL" calendar components need to be
related to each other or to a "VEVENT" or "VTODO" calendar component,
they can specify a relationship with the "RELATED-TO" property.
Example: The following is an example of the "VJOURNAL" calendar
component:
BEGIN:VJOURNAL
UID:19970901T130000Z-123405@host.com
DTSTAMP:19970901T1300Z
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.
2. Telephone Conference: ABC Corp. sales representative called
to discuss new printer. Promised to get us a demo by Friday.
3. Henry Miller (Handsoff Insurance): Car was totaled by tree.
Is looking into a loaner car. 654-2323 (tel).
END:VJOURNAL
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4.6.4 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.
Formal Definition: A "VFREEBUSY" calendar component is defined by the
following notation:
freebusyc = "BEGIN" ":" [WSP] "VFREEBUSY" CRLF
fbprop
"END" ":" [WSP] "VFREEBUSY" CRLF
fbprop = fbrequest / fbreply / busytime
fbrequest = 1*attendee dtstart dtend [duration] *comment dtstamp
[last-mod] [seq] uid
;This set of properties is used for free/busy time request.
fbreply = 1*attendee [created] *comment [dtstart dtend] dtstamp
1*freebusy [last-mod] [rstatus] [seq] uid
[url]
;This set of properties is used for free/busy time reply.
busytime = attendee dtstamp dtstart dtend *comment 1*freebusy
[url]
Description: A "VFREEBUSY" calendar component is a grouping of
component properties that represents either a request for, 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 "VFREEBUSY"
calendar component MUST include the "ATTENDEE", "DTSTAMP", "DTSTART",
"DTEND", and "UID" properties. In addition, it MUST include the
"SEQUENCE" property, if it's value is greater than zero.
When used to reply to a request for free/busy time, the "VFREEBUSY"
calendar component MUST include the "ATTENDEE", "DTSTAMP",
"FREEBUSY", and "UID" properties. In addition, it MUST include the
"SEQUENCE" property, if it's value is greater than zero.
When used to publish busy time, the "VFREEBUSY" calendar component
MUST include the "ATTENDEE", "DTSTAMP", "DTSTART", "DTEND",
"FREEBUSY" properties.
The "VFREEBUSY" calendar component cannot be nested within another
calendar component. Multiple "VFREEBUSY" calendar components MAY 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.
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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 can be expressed using the "FREEBBUSY"
property. This property provides a terse representation of time
periods. One or more "FREEBUSY" properties MAY be specified in the
"VFREEBUSY" calendar component to describe the Free/Busy information.
When present in a "VFREEBUSY" calendar component, the "DTSTART" and
"DTEND" properties SHOULD be specified prior to any "FREEBUSY"
properties. In a free time request, these properties MAY be used in
combination with the "DURATION" property to express a request for a
duration of free time within a given window of time.
The recurrence properties ("RRULE", "EXRULE", "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
ORGANIZER:MAILTO:jane_doe@host1.com
ATTENDEE:MAILTO:john_public@host2.com
DTSTART:19971015T050000Z
DTEND:19971016T050000Z
DTSTAMP:19970901T083000Z
SEQUENCE:0
UID:19970901T0830000-uid1@host1.com
END:VFREEBUSY
The following is an example of a "VFREEBUSY" calendar component used
to reply to the request with busy time information:
BEGIN:VFREEBUSY
ATTENDEE:MAILTO:john_public@host2.com
DTSTAMP:19970901T100000Z
SEQUENCE:0
UID:19970901T0830000-uid1@host1.com
FREEBUSY;VALUE=PERIOD:19971015T050000Z/PT8H30M,
19971015T160000Z/PT5H30M,19971015T223000Z/PT6H30M
URL:http://host2.com/pub/busy/jpublic-01.vcs
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 published busy time information.
BEGIN:VFREEBUSY
ATTENDEE:jsmith@host.com
DTSTART:19980313T141711Z
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DTEND:19980410T141711Z
FREEBUSY:19980314T233000Z/19980315T003000Z
FREEBUSY:19980316T153000Z/19980316T163000Z
FREEBUSY:19980318T030000Z/19980318T040000Z
URL:http://www.host.com/calendar/busytime/jsmith.ifb
END:VFREEBUSY
4.6.5 Timezone Component
Component Name: VTIMEZONE
Purpose: Provide a grouping of component properties that defines a
time zone.
Formal Definition: A "VTIMEZONE" calendar component is defined by the
following notation:
timezonec = "BEGIN" ":" [WSP] "VTIMEZONE" CRLF
tzid [last-mod] [tzurl] 1*(standardc / daylightc)
"END" ":" [WSP] "VTIMEZONE" CRLF
standardc = "BEGIN" ":" [WSP] "STANDARD" CRLF
tzprop
"END" ":" [WSP] "STANDARD" CRLF
daylightc = "BEGIN" ":" [WSP] "DAYLIGHT" CRLF
tzprop
"END" ":" [WSP] "DAYLIGHT" CRLF
tzprop = *comment dtstart [rdate / rrule]
*tzname tzoffsetto tzoffsetfrom
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 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
for the eastern United States starting from 1967. Each line
represents a description or rule for a particular observance.
Effective Observance Rule
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Date (Date/Time) Offset Abbreviation
1967-* lastSun in Oct, 02:00 -0500 EST
1967-1973 last Sun in Apr, 02:00 -0400 EDT
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-* first Sun in Apr, 02:00 -0400 EDT
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 MAY 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 be present if the iCalendar
object contains an RRULE that generates dates on both sides of a time
zone shift (e.g. both in Standard Time and Daylight Saving Time)
UNLESS the iCalendar object intends to convey a floating time (See
the section "4.1.10.11 Time" for proper interpretation of floating
time). It MAY be present if the iCalendar object does not contain
such a RRULE. In addition, if a RRULE is present, there must be valid
time zone information for all recurrence instances.
The "VTIMEZONE" calendar component MUST include the "TZID" property
and at least one definition of a standard or daylight component. The
standard or daylight component MUST include the "DTSTART",
"TZOFFSETFROM" and "TZOFFSETTO" properties.
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
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- 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
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 VTIMZONE 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 url value that points to a published
VTIMEZONE definition.
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 local DATE-TIME value.
The mandatory "TZOFFSETFROM" property gives the UTC offset which 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 1967 for the eastern United States:
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.
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The optional "TZNAME" property is the customary name for the time
zone. It may be specified multiple times, to allow for specifying
multiple language variants of the time zone names. This could be used
for displaying dates.
If specified, the onset for the observance defined by the time zone
sub-component is defined by either the "RRULE" or "RDATE" property.
If neither are specified, only one sub-component can be specified in
the "VTIMEZONE" calendar component and it is assumed that the single
observance specified is always in effect.
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:
- 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 as a full DATE-TIME value, using
local time plus the UTC offset.
- The local time and UTC offset values provided in the "DTSTART"
property for the given observance MUST be used when generating
the onset date-time values (instances) from the RRULE. This
interpretation of the "DTSTART" UTC offset value is specific to
"RRULE" usage in the "VTIMEZONE" specification.
Alternatively, the "RDATE" property MAY 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 local DATE-TIME value
with UTC offset.
The optional "COMMENT" property is also allowed for descriptive
explanatory text.
Example: The following are examples of the "VTIMEZONE" calendar
component:
This is a simple example showing time zone information for the
Eastern United States using "RDATE" property. Note that this is only
suitable for a recurring event that starts on or later than April 6,
1997 at 02:00:00 EST (i.e., the earliest effective transition date
and time) and ends no later than April 7, 1998 02:00:00 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,
8am-9am, starting June 1, 1997, ending December 31, 1997.
BEGIN:VTIMEZONE
TZID:America-New_York
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19971026T020000
RDATE:19971026T020000
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TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19971026T020000
RDATE:19970406T020000
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE
This is a simple example showing the current time zone rules for the
Eastern United States 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 on into the known future.
BEGIN:VTIMEZONE
TZID:America-New_York
LAST-MODIFIED:19870101T000000Z
TZURL:http://zones.stds_r_us.net/tz/America-New_York
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
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE
This is an example showing a fictitious set of rules for the Eastern
United States, where the Daylight Time rule has an effective end date
(i.e., after that date, Daylight Time is no longer observed).
BEGIN:VTIMEZONE
TZID:America-New_York
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
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DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE
This is an example showing a fictitious set of rules for the Eastern
United States, 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:America-New_York
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=19980404T070000
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
4.6.6 Alarm Component
Component Name: VALARM
Purpose: Provide a grouping of component properties that define an
alarm.
Formal Definition: A "VALARM" calendar component is defined by the
following notation:
alarmc = "BEGIN" ":" [WSP] "VALARM" CRLF
(audioprop / dispprop / emailprop
/ procprop)
"END" ":" [WSP] "VALARM" CRLF
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audioprop = alarmtype trigger [duration repeat] attach
dispprop = alarmtype description trigger [duration
repeat]
emailprop = alarmtype 1*attendee *attach description
trigger [duration repeat] summary
procprop = alarmtype attach [description] trigger [duration
repeat]
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 "ALARM-TYPE" and
"TRIGGER" properties. In addition, an AUDIO type of alarm MUST
include the "ATTACH" property to point to a digital sound resource to
be played. The DISPLAY type of alarm MUST include the "DESCRIPTION"
property. The EMAIL type of alarm MUST include the "ATTENDEE",
"DESCRIPTION" and "SUMMARY" properties. The PROCEDURE type of alarm
MUST include the "ATTACH" property to point to a procedure resource
to be invoked.
The "VALARM" calendar component MUST only appear within either a
"VEVENT" or "VTODO" calendar component. The "VALARM" calendar
components cannot be nested. Multiple "VALARM" calendar components
MAY be specified.
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 MAY alternately be set to an absolute calendar date and
time of day value.
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, the "DTEND" or "DTSTART" and "DURATION"
properties MUST be present. In an alarm in a "VTODO" calendar
component set to trigger on the "END" of the to-do, the "DUE" or
"DTSTART" and "DURATION" properties MUST be present.
The alarm MAY be defined such that it triggers repetitively. 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 triggered. This 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
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are absent, then the alarm will not repeat beyond the initial
trigger.
The "ALARM-TYPE" property is used within the "VALARM" calendar
component to specify the type of the alarm. The "ALARM-TYPE" property
value of AUDIO specifies an alarm that triggers with an audio sound;
a value of DISPLAY specifies an alarm that triggers with the
"Calendar User Agent" displaying text; the value of EMAIL specifies
an alarm that triggers the posting of an electronic email message to
one or more email addresses; and the value of PROCEDURE specifies an
alarm that triggers the execution of a procedure. The "ALARM-TYPE"
property MUST specify just one of these valid values. Multiple
categories of alarms MAY BE specified by defining more than one,
different categories of "VALARM" calendar components within a
"VEVENT" or "VTODO" calendar component.
In an AUDIO type of alarm, the "ATTACH" property in the "VALARM"
calendar component MUST specify an audio sound file that is intended
to be rendered as the alarm effect. If an "ATTACH" property is
specified that does not refer to a digital sound resource, then no
audio alarm will be sounded. If the digital sound resource is in a
format that cannot be rendered, then no audio alarm will be sounded.
In a DISPLAY type of alarm, the "DESCRIPTION" property in the
"VALARM" calendar component is intended to be displayed as the alarm
effect. In an EMAIL category of alarm, the intended alarm effect is
to use the "DESCRIPTION" property in the "VALARM" calendar component
as the body text of an email message that is to be sent to the
addresses specified by any "ATTENDEE" properties present in the
"VALARM" calendar component. The "SUMMARY" property in the "VALARM"
calendar component is intended to be used as the subject text for the
email. Any "ATTACH" properties are sent as email attachments.
In a PROCEDURE type of alarm, the "ATTACH" property in the "VALARM"
calendar component MUST specify a procedure or program that is
intended to be invoked as the alarm effect. If the procedure or
program is in a format that cannot be rendered, then no procedure
alarm will be invoked. If the "DESCRIPTION" property is present, its
value specifies the argument string to be passed to the procedure or
program. "Calendar User Agents" that receive an iCalendar object with
this category of alarm, should allow the "Calendar User" to disable
or otherwise ignore this type of alarm. While a very useful alarm
capability, the PROCEDURE type of alarm should be treated by the
"Calendar User Agent" as a potential security risk.
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
ALARM-TYPE: AUDIO
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ATTACH:ftp://host.com/pub/sounds/bell-01.wav
END:VALARM
The following example is for a "VALARM" calendar component that
specifies a display alarm that will trigger 15 minutes before the
scheduled start of the event or the due date/time of the to-do it is
associated with and will repeat 2 more times at 15 minute intervals:
BEGIN:VALARM
TRIGGER:PT30M
REPEAT:2
DURATION:PT15M
ALARM-TYPE: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 it is associated with. It does not
repeat. The email has a subject, body and attachment link.
BEGIN:VALARM
TRIGGER:P2D
ALARM-TYPE:EMAIL
ATTENDEE:MAILTO:john_doe@host.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:http://host.com/templates/agenda.doc
END:VALARM
The following example is for a "VALARM" calendar component that
specifies a procedural alarm that will trigger at a precise date/time
and will repeat 23 more times at one hour intervals. The alarm will
invoke a procedure file.
BEGIN:VALARM
TRIGGER;VALUE=DATE-TIME:19980101T050000Z
REPEAT:23
DURATION:PT1H
ALARM-TYPE:PROCEDURE
ATTACH:ftp://host.com/novo-procs/felizano.exe
END:VALARM
4.7 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"
property and prior to any calendar component.
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4.7.1 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
Conformance: Property MAY be specified in an iCalendar object. The
default value is "GREGORIAN".
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.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
calscale = "CALSCALE" ":" [WSP] calvalue CRLF
calvalue = "GREGORIAN" / iana-token
Example: The following is an example of this property:
CALSCALE:GREGORIAN
4.7.2 Method
Property Name: METHOD
Purpose: This property defines the iCalendar object method associated
with the calendar object.
Value Type: TEXT
Conformance: The property MAY be specified 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. This property can only appear once within the iCalendar
object. 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 [ITIP].
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If this property is not present in the iCalendar object, then no
scheduling transaction MAY be assumed. In such cases, the iCalendar
object is merely being used to transport a snapshot of some calendar
information; without the intention of conveying a scheduling
semantic.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
method = "METHOD" ":" [WSP] method-value CRLF
method-value = iana-token
Example: The following is a hypothetical example of this property to
convey that the iCalendar object is a request for a meeting:
METHOD:REQUEST
4.7.3 Product Identifier
Property Name: PRODID
Purpose: This property specifies the identifier for the product that
created the iCalendar object.
Value Type: TEXT
Conformance: The property MUST be specified in an iCalendar object
but can only appear once.
Description: The vendor of the implementation should assure that this
is a globally unique identifier; using some technique such as an ISO
9070 FPI value.
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.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
prodid = "PRODID" ":" [WSP] pidvalue CRLF
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:
PRODID:-//ABC Corporation//NONSGML My Product//EN
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4.7.4 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
Conformance: This property MUST be specified by in an iCalendar
object, but MAY only be specified once.
Description: A value of "2.0" corresponds to this memo.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
version = "VERSION" ":" [WSP] vervalue CRLF
vervalue = "2.0" ;This memo
/ maxver
/ (minver ";" [WSP] maxver)
minver = <A IANA registered iCalendar version identifier>
;Minimum iCalendar version used to create the iCalendar object
maxver = <A IANA registered iCalendar version identifier>
;Maximum iCalendar version used to create the iCalendar object
Example: The following is an example of this property:
VERSION:2.0
4.8 Component Properties
The following properties MAY appear within calendar components, as
specified by each component property definition.
4.8.1 Descriptive Component Properties
The following properties specify descriptive information about
calendar components.
4.8.1.1 Attachment
Property Name: ATTACH
Purpose: The property provides the capability to associate a document
object with a calendar component.
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Value Type: The default value type for this property is URI. The
value type MAY also be reset to BINARY in order to include inline
binary encoded content information.
Conformance: The property MAY be specified in an iCalendar object.
Description: The property MAY only be specified within "VEVENT",
"VTODO", "VJOURNAL", or "VALARM" calendar components. This property
MAY be specified multiple times within an iCalendar object.
Only the "ENCODING" and "VALUE", property parameters MAY be specified
on this property.
Format Definition: The property is defined by the following notation:
attach = ("ATTACH" ":" [WSP] uri CRLF)
attach =/ ("ATTACH" ";" [WSP] "ENCODING" "=" "b" ";" [WSP]
"VALUE" "=" "text" ":" [WSP] binary
Example: The following are examples of this property:
ATTACH:CID:jsmith.part3.960817T083000.xyzMail@host1.com
ATTACH:FTP://xyzCorp.com/pub/reports/r-960812.ps
4.8.1.2 Categories
Property Name: CATEGORIES
Purpose: This property defines the categories for a calendar
component.
Value Type: TEXT
Conformance: The property MAY only be specified within "VEVENT",
"VTODO" or "VJOURNAL" calendar components.
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 MAY be specified as a list of categories separated by the
COMMA character (ASCII decimal 44).
Only the "LANGUAGE" property parameters MAY be specified on this
property.
Format Definition: The property is defined by the following notation:
categories = "CATEGORIES" [catparam] ":" [WSP] catvalue CRLF
catparam = ";" [WSP] languageparm
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catvalue = "ANNIVERSARY" / "APPOINTMENT" / "BUSINESS"
/ "EDUCATION" / "HOLIDAY" / "MEETING" / "MISCELLANEOUS"
/ "NON-WORKING HOURS" / "NOT IN OFFICE" / "PERSONAL"
/ "PHONE CALL" / "SICK DAY" / "SPECIAL OCCASION"
/ "TRAVEL" / "VACATION" / text
;These are just examples
;Used only in "VEVENT", "VTODO" and "VJOURNAL" calendar components.
Example: The following are examples of this property:
CATEGORIES:APPOINTMENT,EDUCATION
CATEGORIES:MEETING
4.8.1.3 Classification
Property Name: CLASS
Purpose: This property defines the access classification for a
calendar component.
Value Type: TEXT
Conformance: The property MAY only be specified in a "VEVENT",
"VTODO" or "VJOURNAL" calendar components. The property MAY only be
specified once.
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. The
[ICMS] provides a broader description of the security system within a
calendar application.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
class = "CLASS" ":" [WSP] classvalue CRLF
classvalue = "PUBLIC" / "PRIVATE" / "CONFIDENTIAL" / iana-token
/ x-name
;Default is PUBLIC
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Example: The following is an example of this property:
CLASS:PUBLIC
4.8.1.4 Comment
Property Name: COMMENT
Purpose: This property specifies non-processing information intended
to provide a comment to the calendar user.
Value Type: TEXT
Conformance: This property may be specified in an iCalendar object.
Description: The property MAY be specified multiple times.
Only the "ALTREP" or "LANGUAGE" property parameters MAY be specified
on this property.
Format Definition: The property is defined by the following notation:
The property MAY be specified in any of the calendar components.
comment = "COMMENT" [commparam] ":" [WSP] text CRLF
commparam = [";" [WSP] altrepparm ] [";" [WSP] languageparm]
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
The data type for this property is TEXT.
4.8.1.5 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
Conformance: The property MAY be specified in the "VEVENT", "VTODO"
and "VJOURNAL" calendar components. The property MAY be specified
multiple times only within a "VJOURNAL" calendar component. The
property MAY be specified in "VALARM" calendar component.
Description: This property is used in the "VEVENT" and "VTODO" to
capture lengthy textual decriptions associated with the activity.
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This property is used in the "VJOURNAL" calendar component to capture
one more textual journal entries.
This property is used in the "VALARM" calendar component to capture
the display text for a DISPLAY category of alarm, to capture the body
text for an EMAIL category of alarm and to capture the arguement
string for a PROCEDURE category of alarm.
Only the "ALTREP" or "LANGUAGE" property parameters MAY be specified
on this property.
Format Definition: The property is defined by the following notation:
description = "DESCRIPTION" [descparam] ":" [WSP] text CRLF
descparam = [";" [WSP] altrepparm] [";" [WSP] languageparm]
Example: The following is an example of the property with formatted
line breaks in the property value:
DESCRIPTION:Meeting to provide technical review for "Phoenix"
design.\n Happy Face Conference Room. Phoenix design team
MUST attend this meeting.\n RSVP to team leader.
The following is an example of the property with folding of long
lines:
DESCRIPTION:Last draft of the new novel is to be completed
for the editor's proof today.
4.8.1.6 Geographic Position
Property Name: GEO
Purpose: This property specifies information related to the global
position for the activity specified by a calendar component.
Value Type: Two FLOAT values.
Conformance: This property MAY be specified in an iCalendar object.
Description: The property value specifies latitude and longitude, in
that order (i.e., "LAT LON" ordering). The longitude represents the
location east and west of the prime meridian as a positive or
negative real number, respectively. The latitude represents the
location north and south of the equator as a positive or negative
real number, respectively. The longitude and latitude values MUST be
specified as decimal degrees and should be specified to six decimal
places. This will allow for granularity within a meter of the
geographical position. The simple formula for converting degrees-
minutes-seconds into decimal degrees is:
decimal = degrees + minutes/60 + seconds/3600.
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No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
geo = "GEO" ":" [WSP] geovalue CRLF
geovalue = float ";" [WSP] float
;Latitude and Longitude components
Example: The following is an example of this property:
GEO:37.386013;-122.082932
4.8.1.7 Location
Property Name: LOCATION
Purpose: The property defines the intended venue for the activity
defined by a calendar component.
Value Type: TEXT
Conformance: This property MAY be specified in the "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 URI pointing to an LDAP server entry or a CID URI
pointing to a MIME body part containing a vCard for the location.
Only the "ALTREP" or "LANGUAGE" property parameters MAY be specified
on this property.
Format Definition: The property is defined by the following notation:
location = "LOCATION [locparam] ":" [WSP] text CRLF
locparam = [";" [WSP] altrepparm] [";" [WSP] languageparm]
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
4.8.1.8 Percent Complete
Property Name: PERCENT-COMPLETE
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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
Conformance: This property MAY only be specified in a "VTODO"
calendar component.
Description: The property value is a postive integer between zero and
one hundred. 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.
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.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
percent = "PERCENT-COMPLETE" ":" [WSP] integer CRLF
Example: The following is an example of this property to show 39%
completion:
PERCENT-COMPLETE:39
4.8.1.9 Priority
Property Name: PRIORITY
Purpose: The property defines the relative priority for a calendar
component.
Value Type: INTEGER
Conformance: The property MAY only be specified in a "VEVENT" or
"VTODO" calendar component.
Description: The priority is specified as an integer in the range
zero to nine. A value of zero (ASCII decimal 48) specifies an
undefined priority. A value of one (ASCII decimal 49) is the highest
priority. A value of two (ASCII decimal 50) is the second highest
priority. Subsequent numbers specify a decreasing ordinal priority. A
value of nine (ASCII decimal 58) 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
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range of one (ASCII decimal 49) to four (ASCII decimal 52) specifies
"HIGH" priority. A value of five (ASCII decimal 53) is the normal or
"MEDIUM" priority. A value in the range of six (ASCII decimal 54) to
nine (ASCII decimal 58) is "LOW" priority.
A CUA with a priority schema of "A1", "A2", "A3", "B1", "B2", ...,
"C3" is mapped into this property such that a property value of one
(ASCII decimal 49) specifies "A1", a property value of two (ASCII
decimal 50) specifies "A2", a property value of three (ASCII decimal
51) specifies "A3", and so forth up to a property value of 9 (ASCII
decimal 58) 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.
No property parameters MAY be specified on this property.
Format Definition: The property is specified by the following
notation:
priority = "PRIORITY" ":" [WSP] privalue CRLF
;Default is zero
privalue = integer ;Must be in the range [0..9]
; All other values are reserved for future use
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
Example: The following is an example of a property with no priority.
This is equivalent to not specifying the "PRIORITY" property.:
PRIORITY:0
4.8.1.10 Resources
Property Name: RESOURCES
Purpose: This property defines the equipment or resources anticipated
for an activity specified by a calendar entity..
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Value Type: TEXT
Conformance: This property MAY be specified in a "VEVENT" or "VTODO"
calendar component.
Description: The property value is an arbitrary text. More than one
resource MAY be specified as a list of resources separated by the
COMMA character (ASCII decimal 44).
Only the "LANGUAGE" property parameter MAY be specified on this
property.
Format Definition: The property is defined by the following notation:
resources = "RESOURCES" [resrcparam] ":" [WSP] resvalist CRLF
resrcparam = ";" [WSP] languageparm
resvalist = resvalue / resvalue "," [WSP] resvalist
resvalue = "CATERING" / "CHAIRS" / "COMPUTER PROJECTOR"
/ "EASEL" / "OVERHEAD PROJECTOR" / "SPEAKER PHONE"
/ "TABLE" / "TV" / "VCR" / "VIDEO PHONE" / "VEHICLE"
/ text
;These are just examples.
Example: The following is an example of this property:
RESOURCES:EASEL,PROJECTOR,VCR
4.8.1.11 Status
Property Name: STATUS
Purpose: This property defines the overall status or confirmation for
the calendar component.
Value Type: TEXT
Conformance: This property MAY only be specified in the "VEVENT",
"VTODO", "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.
No property parameter MAY be specified on this property.
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Format Definition: The property is defined by the following notation:
status = "STATUS" ":" [WSP] statvalue CRLF
statvalue = "TENTATIVE" ;Indicates event is
;tentative.
/ "CONFIRMED" ;Indicates event is
;definite.
/ "CANCELLED" ;Indicates event was
;cancelled.
;Status values for a "VEVENT"
statvalue =/ "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".
statvalue =/ "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
4.8.1.12 Summary
Property Name: SUMMARY
Purpose: This property defines a short summary or subject for the
calendar component.
Value Type: TEXT
Conformance: The property MUST be specified in the "VEVENT", "VTODO"
and "VJOURNAL" calendar components. In addition, it MAY appear in the
"VALARM" calendar component.
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.
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This property is used in the "VALARM" calendar component to capture
the subject of an EMAIL category of alarm.
Only the "ALTREP" and "LANGUAGE" property parameters MAY be specified
on this property.
Format Definition: The property is defined by the following notation:
summary = "SUMMARY" [summparam] ":" [WSP] text CRLF
summparam = [";" [WSP] altrepparm] [";" [WSP] languageparm]
Example: The following is an example of this property:
SUMMARY:Department Party
4.8.2 Date and Time Component Properties
The following properties specify date and time related information in
calendar components.
4.8.2.1 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
Conformance: The property MAY only be specified in a "VTODO"
component in an iCalendar object.
Description: The date and time must be in a UTC format.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
completed = "COMPLETED" ":" [WSP] date-time CRLF
Example: The following is an example of this property:
COMPLETED:19960401T235959Z
4.8.2.2 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 MAY
BE reset to a DATE value type.
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Conformance: This property MAY only be specified within the "VEVENT",
"VFREEBUSY", and "VTIMEZONE" calendar components.
Description: Within the "VEVENT" calendar component, this property
defines the date and time by which the event ends. The value MUST be
later in time than the value of the "DTSTART" property.
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 as in the UTC time format. The value MUST be later
in time than the value of the "DTSTART" property.
Only the "VALUE" and "TZID" property parameters MAY be specified on
this property. The "TZID" property parameter MAY only be specified
when the value type is DATE-TIME.
Format Definition: The property is defined by the following notation:
dtend = "DTEND" [dtendparam]":" [WSP] dtendval CRLF
dtendparam = [";" [WSP] "VALUE" "=" "DATE-TIME"]
[";" [WSP] "TZID" "=" paramtext
dtendparam =/ ";" [WSP] "VALUE" "=" "DATE"
dtendval = date-time / date
;Value MUST match value type
Example: The following is an example of this property:
DTEND:19960401T235959Z
DTEND;VALUE=DATE:19980704
4.8.2.3 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 MAY
BE reset to a DATE value type.
Conformance: The property MAY only be specified in a "VTODO" calendar
component and only once.
Description: The value MUST be a date/time equal to or after the
DTSTART value, if specified.
Only the "VALUE" and "TZID" property parameters MAY be specified on
this property. The "TZID" property parameter MAY only be specified
when the value type is DATE-TIME.
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Format Definition: The property is defined by the following notation:
due = "DUE" [dueparam]":" [WSP] dueval CRLF
dueparam = [";" [WSP] "VALUE" "=" "DATE-TIME"]
[";" [WSP] "TZID" "=" paramtext
dueparam =/ ";" [WSP] "VALUE" "=" "DATE"
dueval = date-time / date
;Value MUST match value type
Example: The following is an example of this property:
DUE:19960401T235959Z
4.8.2.4 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 DATE-TYPE value
will be one of the forms defined for the DATE-TIME value type. The
value type MAY BE reset to a DATE value type.
Conformance: This property MAY be specified within the "VEVENT",
"VTODO", "VFREEBUSY", and "VTIMEZONE" calendar components.
Description: Within the "VEVENT" calendar component, this property
defines the start date and time for the event. The property is
REQUIRED in "VEVENT" calendar components. Events MAY have a start
date/time but no end date/time. In that case, the event does not take
up any time.
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 "VTIMEZONE" calendar component, this property defines the
effective start date and time for a time zone specification. This
property is REQUIRED within "VTIMEZONE" calendar components. The time
MUST be specified in the UTC time format.
Only the "VALUE" and "TZID" property parameters MAY be specified on
this property. The "TZID" property parameter MAY only be specified
when the value type is DATE-TIME.
Format Definition: The property is defined by the following notation:
dtstart = "DTSTART" [dtstparam] ":" [WSP] dtstval CRLF
dtstparam = [";" [WSP] "VALUE" "=" "DATE-TIME"]
[";" [WSP] "TZID" "=" paramtext]
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dtstparam =/ ";" [WSP] "VALUE" "=" "DATE"
dtstval = date-time / date
;Value MUST match value type
Example: The following is an example of this property:
DTSTART:19980118T073000Z
4.8.2.5 Duration
Property Name: DURATION
Purpose: The property specifies a duration of time .
Value Type: DURATION
Conformance: The property MAY be specified in a "VEVENT", "VTODO",
"VFREEBUSY" 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 "VFREEBUSY" calendar component the property may be
used to specify the interval of free time being requested. In a
"VALARM" calendar component the property may be used to specify the
delay period prior to repeating an alarm.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
duration = "DURATION" ":" [WSP] duration CRLF
Example: The following is an example of this property that specifies
an interval of time of 1 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
4.8.2.6 Free/Busy Time
Property Name: FREEBUSY
Purpose: The property defines one or more free or busy time
intervals.
Value Type: PERIOD. The data and time value MUST be in a UTC time
format.
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Conformance: The property MAY only be specified in a "VFREEBUSY"
calendar component.
Description: These time periods MAY 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.
The "FREEBUSY" property MAY include the "TYPE" property parameter to
specify whether the information defines a FREE or BUSY time interval.
The default "TYPE" property parameter value is BUSY.
If the "TYPE" property parameter is set to "BUSY", then the property
MAY also include the "BSTAT" property parameter to provide added
information about the busy time. For example, if the busy time is
associated with a time interval that would be unavailable for
scheduling in any case the parameter MAY BE set to UNAVAILABLE or if
the busy time that has been tentatively scheduled the parameter MAY
BE set to TENTATIVE. The default "BSTAT" property parameter value is
BUSY, providing no additional busy status information.
"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 MAY specify more than one value, separated by
the COMMA character (ASCII decimal 44). In such cases, the "FREEBUSY"
property values should all be of the same "TYPE" and "BSTAT" property
parameter type (e.g., all values of a particular "TYPE" and "BSTAT"
listed together in a single property).
No property parameters other than the property specific "TYPE" and
"BSTAT" parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
freebusy = "FREEBUSY" [";" [WSP] fbparmlist] ":" [WSP] fbvalue
CRLF
fbparmlist = fb-free / fb-busy
fb-free = "TYPE" "=" "FREE"
fb-busy = ["TYPE" "=" "BUSY"] [";" [WSP] fbstatus]
;Default is BUSY
fbstatus = "BSTAT" "="
"BUSY" ;Represents busy time interval.
/ "UNAVAILABLE" ;Represents busy, but unavailable
;interval for cheduling; such as
;out-of-office or non-working hours.
/ "TENTATIVE" ;Represents busy, but only tentatively
;scheduled interval.
/ iana-token ;Represents other registered busy status
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/ x-name ;Represents experimental busy status
;Default is BUSY
fbvalue = period *["," [WSP] period]
;Time value MUST be in the UTC time format.
Example: The following are some examples of this property:
FREEBUSY;BSTAT=UNAVAILABLE:19970308T160000Z/PT8H30M
FREEBUSY;TYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H
4.8.2.7 Time Transparency
Property Name: TRANSP
Purpose: This property defines whether an event is transparent or not
to busy time searches.
Value Type: TEXT
Conformance: This property MAY only be specified in a "VEVENT"
calendar component.
Description: Transparency is the state that determines whether an
event takes up time on a calendar, and with be reflected as "busy
time", or is just "penciled in" to the calendar, and will not be
reflected as "busy time". If the event is transparent, then other
events can be scheduled in the same time period without there being a
time period conflict. If not specified, the default state is OPAQUE.
No property parameters MAY be specified on this property.
Format Definition: The property is specified by the following
notation:
transp = "TRANSP" ":" [WSP] transvalue CRLF
transvalue = "OPAQUE" ;Blocks or opaque on busy time searches.
/ "TRANSPARENT" ;Transparent on busy time searches.
;Default value is OPAQUE
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
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4.8.3 Time Zone Component Properties
The following properties specify time zone information in calendar
components.
4.8.3.1 Time Zone Identifier
Property Name: TZID
Purpose: This property specifies the text value that uniquely
identifies the VTIMZONE calendar component.
Value Type: TEXT
Conformance: This property MUST be specified in a "VTIMEZONE"
calendar component.
Description: This is the key by which a time zone object is
referenced by any iCalendar properties whose data type is either
DATE-TIME or TIME. The presence of the SOLIDUS character (ASCII
decimal 47) as a prefix, indicates that this TZID represents an
unique ID in a globally defined time zone registry (when such
registry is defined).
No property parameters MAY be specified on this property.
Format Definition: This property is defined by the following
notation:
tzid = "TZID" ":" [WSP] [tzidprefix] text CRLF
tzidprefix = "/"
Example: The following are examples of non-globally unique time zone
identifiers:
TZID:America-New_York
TZID:/US-California-Los_Angeles
The following is an example of a globally unique time zone
identifier:
TZID:/US-New York-New_York
4.8.3.2 Time Zone Name
Property Name: TZNAME
Purpose: This property specifies the customary designation for a time
zone description.
Value Type: TEXT
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Conformance: This property MAY only be specified in the "VTIMEZONE"
calendar component.
Description: This property may be specified in multiple languages; in
order to provide for different national language requirements.
Only the "LANGUAGE" property parameter MAY be specified on this
property.
Format Definition: This property is defined by the following
notation:
tzname = "TZNAME" [tznparam] ":" [WSP] text CRLF
tznparam = ";" [WSP] languageparm
Example: The following are examples of this property:
TZNAME: EST
TZNAME;LANGUAGE=fr-CA:HNE
4.8.3.3 Time Zone Offset From
Property Name: TZOFFSETFROM
Purpose: This property specifies the offset which is in use prior to
this time zone observance.
Value Type: UTC-OFFSET
Conformance: This property MUST only be specified in a "VTIMEZONE"
calendar component. A "VTIMEZONE" calendar component MUST include
this property.
Description: This property specifies the offset which 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 represents time zones
east, or ahead of UTC. Negative numbers represents time zones west
of, or behind UTC.
No property parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
tzoffsetfrom = "TZOFFSETFROM" ":" [WSP] utc-offset CRLF
Example: The following are examples of this property:
TZOFFSETFROM:-0500
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TZOFFSETFROM:+0530
4.8.3.4 Time Zone Offset To
Property Name: TZOFFSETTO
Purpose: This property specifies the offset which is in use in this
time zone observance.
Value Type: UTC-OFFSET
Conformance: This property MAY only be specified in a "VTIMEZONE"
calendar component. A "VTIMEZONE" calendar component MUST include
this property.
Description: This property specifies the offset which 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 represents time zones east, or ahead of UTC.
Negative numbers represents time zones west of, or behind UTC.
No property parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
tzoffsetto = "TZOFFSETTO" ":" [WSP] utc-offset CRLF
Example: The following are examples of this property:
TZOFFSETTO:-0500
TZOFFSETTO:+0530
4.8.3.5 Time Zone URL
Property Name: TZURL
Purpose: The TZURL 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
Conformance: This property MAY only be specified in a "VTIMEZONE"
calendar component.
Description: The TZURL 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 timezone definitions. Retrieval of
this resource results in an iCalendar object containing a single
VTIMEZONE component and a METHOD property set to PUBLISH.
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No property parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
tzurl = "TZURL" ":" [WSP] uri CRLF
Example: The following is an example of this property:
TZURL:http://timezones.r.us.net/tz/US-California-Los_Angeles
4.8.4 Relationship Component Properties
The following properties specify relationship information in calendar
components.
4.8.4.1 Attendee
Property Name: ATTENDEE
Purpose: The property defines an attendee within a calendar
component.
Value Type: CAL-ADDRESS
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 is not specified in an
iCalendar object that specifies only a time zone definition or that
defines calendar entities that are not group scheduled entities, but
are entities only on a single user's calendar.
Description: The property is specified within the "VEVENT", "VTODO",
"VJOURNAL calendar components to specify participants, non-
participants and the chair of a group scheduled calendar entity. The
property is specified within the "VFREEBUSY" calendar component to
specify the calendar user associated with the free or busy time. 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 has the property parameter CN, 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;
ATTSTAT, for the status of the attendee's participation; RSVP, for
indicating whether the favor of a reply is requested; EXPECT, to
indicate the expectation of the attendee's participation by the
originator; 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 MAY only be specified on an "ATTENDEE" property
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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.
A recipient delegated a request MUST inherit the RSVP and EXPECT
values from the attendee that delegated the request to them.
Multiple attendees MAY be specified by including multiple "ATTENDEE"
properties within the MIME calendaring entity.
Only the "TYPE", "CN", "ROLE", "ATTSTAT", "RSVP", "DELEGATED-TO",
"DELEGATED-FROM", "SENT-BY" or "DIR" property specific parameters MAY
be specified on this property. In addition, the "LANGUAGE" property
parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
attendee = "ATTENDEE" *(";" [WSP] attparam) ":" [WSP]
cal-address CRLF
attparam = typeparm / cnparm / roleparm / statusparm / rsvpparm
/ memberparm / deletoparm / delefromparm
/ sentbyparm / dirparm
typeparm = "TYPE" "="
("INDIVIDUAL" ; An individual
/ "GROUP" ; A group of individuals
/ "RESOURCE" ; A physical resource
/ "ROOM" ; A room resource
/ "UNKNOWN") ; Otherwise not known
;Default value is INDIVIDUAL
cnparm = "CN" "=" param-value
roleparm = "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
;Default is REQ-PARTICIPANT
statusparm = "ATTSTAT" "="
("NEEDS-ACTION" ; Indicates event or to-do needs action
/ "ACCEPTED" ; Indicates event or to-do accepted
/ "DECLINED" ; Indicates event or to-do not accepted
/ "TENTATIVE" ; Indicates event or to-do tentatively
; accepted. Status MAY change in the future.
/ "COMPLETED" ; Indicates to-do was completed.
; COMPLETED property has date/time completed.
/ "IN-PROCESS" ;Indicates to-do is in the process of
; being completed.
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/ "DELEGATED" ; Indicates event or to-do delegated
; to another ATTENDEE
;Default is NEEDS-ACTION
rsvpparm = "RSVP" "="
("TRUE" ; Indicates response requested
/ "FALSE") ; Indicates no response needed
;Default is FALSE
memberparm = "MEMBER" "=" DQUOTE uri DQUOTE
*("," [WSP] DQUOTE uri DQUOTE)
; Indicates a group or mailing list
; MUST be a MAILTO URI as defined in [RFC 1738]
; The parameter value must be put in a quoted string.
deletoparm = "DELEGATED-TO" "=" DQUOTE uri DQUOTE
*("," [WSP] DQUOTE uri DQUOTE)
; Indicates who the request is delegated to
; MUST be a MAILTO URI as defined in [RFC 1738]
; The parameter value must be put in a quoted string.delefromparm =
"DELEGATED-FROM" "=" DQUOTE uri DQUOTE
*("," [WSP]DQUOTE uri DQUOTE)
;Indicates who the request is delegated from
; MUST be a MAILTO URI as defined in [RFC 1738]
; The parameter value must be put in a quoted string.
sentbyparm = "SENT-BY" "=" DQUOTE uri DQUOTE
; Indicates a calendar user acting on behalf of the attendee.
; MUST be a MAILTO URI as defined in [RFC 1738]
; The parameter value must be put in a quoted string.dirparm
= "DIR" "=" DQUOTE uri DQUOTE
Example: The following are examples of this property's use for a to-
do:
ORGANIZER:MAILTO:jsmith@host1.com
ATTENDEE;MEMBER="MAILTO:DEV-GROUP@host2.com":
MAILTO:joecool@host2.com
ATTENDEE;DELEGATED-FROM="MAILTO:immud@host3.com":
MAILTO:ildoit@host1.com
The following is an example of this property used for specifying
multiple attendees to an event:
ORGANIZER:MAILTO:jsmith@host1.com
ATTENDEE;ROLE=REQ-PARTICIPANT;ATTSTAT=TENTATIVE;CN=Henry Cabot
:MAILTO:hcabot@host2.com
ATTENDEE;ROLE=REQ-PARTICIPANT;DELEGATED-FROM="MAILTO:bob@host.com"
;ATTSTAT=ACCEPTED;CN=Jane Doe: MAILTO:jdoe@host1.com
The following is an example of this property with a URI to the
directory information associated with the attendee:
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ATTENDEE;CN=John Smith;DIR="ldap://host.com:6666/o=eDABC%
20Industries,c=3DUS??(cn=3DBJim%20Dolittle)":MAILTO:jimdo@
host1.com
The following is an example of this property with "delegatee" and
"delegator" information for an event:
ORGANIZER;CN=John Smith:MAILTO:jsmith@host.com
ATTENDEE;ROLE=REQ-PARTICIPANT;ATTSTAT=TENTATIVE;DELEGATED-FROM=
"MAILTO:iamboss@host2.com";CN=Henry Cabot:MAILTO:hcabot@
host2.com
ATTENDEE;ROLE=NON-PARTICIPANT;ATTSTAT=DELEGATED;DELEGATED-TO=
"MAILTO:hcabot@host2.com";CN=The Big Cheese:MAILTO:iamboss
@host2.com
ATTENDEE;ROLE=REQ-PARTICIPANT;ATTSTAT=ACCEPTED;CN=Jane Doe
:MAILTO:jdoe@host1.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@host1.com;CN=John Smith:MAILTO:
jsmith@host1.com
4.8.4.2 Contact
Property Name: CONTACT
Purpose: The property is used to represent contact information or
alternately a reference to contact information associated with the
calendar component.
Value Type: TEXT
Conformance: The property MAY only be specified in a "VEVENT",
"VTODO" and "VJOURNAL" calendar component in an iCalendar object.
Description: The property value consists of textual contact
information. An alternative representation for the property value MAY
also be specified that refers to a URI pointing to an alternate form,
such as a vCard, for the contact information.
Only the "ALTREP" or "LANGUAGE" property parameters MAY be specified
on this property.
Format Definition: The property is defined by the following notation:
contact = "CONTACT" [contparam] ":" [WSP] text CRLF
contparam = [";" [WSP] altrepparm] [";" [WSP] languageparm]
Example: The following is an example of this property referencing
textual contact information:
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CONTACT:Jim Dolittle\, ABC Industries\, +1-919-555-1234
The following is an example of this property with an alternate
representation of a LDAP URI to a directory entry containing the
contact information:
CONTACT;ALTREP="ldap://host.com:6666/o=3DABC%20Industries\,
c=3DUS??(cn=3DBJim%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 embedded in a [MIME-DIR] content-type:
CONTACT;ALTREP="CID=<part3.msg970930T083000SILVER@host.com>":Jim
Dolittle\, ABC Industries\, +1-919-555-1234
The following is an example of this property referencing a network
resource, such as a vCard object containing the contact information:
CONTACT;ALTREP="http://host.com/pdi/jdoe.vcf":Jim
Dolittle\, ABC Industries\, +1-919-555-1234
4.8.4.3 Organizer
Property Name: ORGANIZER
Purpose: The property defines the organizer for a calendar component.
Value Type: CAL-ADDRESS
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 entities that are not group scheduled entities,
but are entities only on a single user's calendar.
Description: The property is specified within the "VEVENT", "VTODO",
"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.
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". No other parameters MAY be
specified on this property.
Format Definition: The property is defined by the following notation:
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organizer = "ORGANIZER" [orgparam] ":" [WSP]
cal-address CRLF
orgparam = [";" [WSP] "CN" "=" param-value]
[";" [WSP] "DIR" "=" DQUOTE uri DQUOTE]
proxyparam
proxyparam = (";" [WSP] "SENT-BY" "=" DQUOTE cal-address DQUOTE)
Example: The following is an example of this property:
ORGANIZER;CN=John Smith:MAILTO:jsmith@host1.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://host.com:6666/o=3DDC%20Associ
ates,c=3DUS??(cn=3DJohn%20Smith)":MAILTO:jsmith@host1.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@host.com":
MAILTO:jsmith@host1.com
4.8.4.4 Recurrence ID
Property Name: RECURRENCE-ID
Purpose: This property is used in conjunction with the "UID" and
"SEQUENCE" property to identify a specific instance of a recurring
"VEVENT", "VTODO" or "VJOURNAL" calendar component. The property
value is the effective value of the "DTSTART" property of the
recurrence instance.
Value Type: The default value type for this property is DATE-TIME.
The time format MAY BE any of the valid forms defined for a DATE-TIME
value type. See DATE-TIME value type definition for specific
interpretations of the various forms. The value type MAY be reset to
DATE.
Conformance: This property MAY 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.
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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" property 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. When the definition of the recurrence
set for a calendar component changes, and hence the "SEQUENCE"
property value changes, the "RECURRENCE-ID" for a given recurrence
instance might also change.The "RANGE" parameter is used to specify
the effective range of recurrence instances from the instance
specified by the "RECURRENCE-ID" property value. The default value
for the range parameter is the single recurrence instance only. The
value can also be "THISANDPRIOR" to indicate a range defined by the
given recurrence instance and all prior instances or the value can be
"THISANDFUTURE" to indicate a range defined by the given recurrence
instance and all subsequent instances.
Only the "VALUE" property parameter and the property-specific "RANGE"
parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
recurid = "RECURRENCE-ID" *(";" [WSP] parameter)
[";" [WSP] rangeparm] ":" [WSP] [date-time / date]
;Value must match value type.
recurid = "RECURRENCE-ID" [ridparam] [rangeparm] ":" [WSP]
ridval CRLF
ridparam = ";" [WSP] "VALUE" "=" ("DATE-TIME" / "DATE" /
/ "PERIOD")
rangeparm = ";" [WSP] "RANGE" "=" ("THISANDPRIOR"
/ "THISANDFUTURE")
ridval = date-time / date / period
;Value MUST match value type
Example: The following are examples of this property:
RECURRENCE-ID;VALUE=DATE:19960401
RECURRENCE-ID;RANGE=THISANDFUTURE:19960120T120000Z
4.8.4.5 Related To
Property Name: RELATED-TO
Purpose: The property is used to represent a relationship or
reference between one calendar component and another.
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Value Type: TEXT
Conformance: The property MAY only be specified once 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 MAY have
an implied impact to 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 canceled 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.
Only the property specific "RELTYPE" parameter MAY be specified on
this property.
Format Definition: The property is defined by the following notation:
related = "RELATED-TO" [";" [WSP] relparam) ":" [WSP] text CRLF
relparam = "RELTYPE" "="
"PARENT" ; Parent relationship. Default.
/ "CHILD" ; Child relationship.
/ "SIBLING" ; Sibling relationship.
The following is an example of this property:
RELATED-TO:<jsmith.part7.19960817T083000.xyzMail@host3.com>
RELATED-TO:<19960401-080045-4000F192713-0052@host1.com>
4.8.4.6 Uniform Resource Locator
Property Name: URL
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Purpose: This property defines a Uniform Resource Locator (URL)
associated with the iCalendar object.
Value Type: URI
Conformance: This property MAY be specified once in the "VEVENT",
"VTODO", "VJOURNAL" and "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
No property parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
url = "URL" ":" [WSP] uri CRLF
Example: The following is an example of this property:
URL:http://abc.com/pub/calendars/jsmith/mytime.or3
4.8.4.7 Unique Identifier
Property Name: UID
Purpose: This property defines the persistent, globally unique
identifier for the calendar component.
Value Type: TEXT
Conformance: The property MUST be specified in the "VEVENT", "VTODO",
"VJOURNAL" and "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. The identifier is RECOMMENDED to be the identical syntax to the
[RFC 822] addr-spec. 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 the "@", 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
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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.
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 characters for this property.
No property parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
uid = "UID" ":" [WSP] text CRLF
Example: The following is an example of this property:
UID:19960401T080045Z-4000F192713-0052@host1.com
4.8.5 Recurrence Component Properties
The following properties specify recurrence information in calendar
components.
4.8.5.1 Exception Date/Times
Property Name: EXDATE
Purpose: This property defines the list of date/time exceptions for a
recurring calendar component.
Value Type: The default value type for this property is DATE-TIME.
The value type MAY be reset to DATE.
Conformance: This property MAY be specified in an iCalendar object
that includes a recurring calendar component.
Description: The exception dates, 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
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generated by considering the initial "DTSTART" property along with
the "RRULE", "RDATE", "EXDATE" and "EXRULE" properties contained
within the iCalendar object. The "DTSTART" property defines the first
instance in the recurrence set. Multiple instances of the "RRULE" and
"EXRULE" properties MAY also be specified to define more
sophisticated recurrence sets. The final recurrence set is generated
by gathering all of the start date-times generated by any of the
specified "RRULE" and "RDATE" properties, and excluding any start
date and times which fall within the union of start date and times
generated by any specified "EXRULE" and "EXDATE" properties. This
implies that start date and times within exclusion related properties
(i.e., "EXDATE" and "EXRULE") 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.
The "EXDATE" property MAY 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".
Only the "VALUE" and "TZID" property parameters MAY be specified on
this property. The "TZID" property parameter MAY only be specified
when the value type is DATE-TIME.
Format Definition: The property is defined by the following notation:
exdate = "EXDATE" [exdtparam] ":" [WSP] exdtval CRLF
exdtparam = [";" [WSP] "VALUE" "=" "DATE-TIME"]
[";" [WSP] "TZID" "=" paramtext]
exdtparam =/ ";" [WSP] "VALUE" "=" "DATE"
exdtval = date-time / date
;Value MUST match value type
Example: The following is an example of this property:
EXDATE:19960402T010000Z,19960403T010000Z,19960404T010000Z
4.8.5.2 Exception Rule
Property Name: EXRULE
Purpose: This property defines a rule or repeating pattern for an
exception to a recurrence set.
Value Type: RECUR
Conformance: This property MAY only be specified in the "VEVENT",
"VTODO" or "VJOURNAL" calendar components.
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Description: The exception 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", "EXDATE" and "EXRULE" properties contained
within the iCalendar object. The "DTSTART" defines the first instance
in the recurrence set. Multiple instances of the "RRULE" and "EXRULE"
properties MAY also be specified to define more sophisticated
recurrence sets. The final recurrence set is generated by gathering
all of the start date-times generated by any of the specified "RRULE"
and "RDATE" properties, and excluding any start date and times which
fall within the union of start date and times generated by any
specified "EXRULE" and "EXDATE" properties. This implies that start
date and times within exclusion related properties (i.e., "EXDATE"
and "EXRULE") 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.
The "EXRULE" property MAY 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".
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
exrule = "EXRULE" ":" [WSP] recur CRLF
Example: The following are examples of this property. Except every
other week, on Tuesday and Thursday for 4 occurrences:
EXRULE:FREQ=WEEKLY;COUNT=4;INTERVAL=2;BYDAY=TU,TH
Except daily for 10 occurrences:
EXRULE:FREQ=DAILY;COUNT=10
Except yearly in June and July for 8 occurrences:
EXRULE:FREQ=YEARLY;COUNT=8;BYMONTH=6,7
The data type for this property is RECUR.
4.8.5.3 Recurrence Date/Times
Property Name: RDATE
Purpose: This property defines the list of date/times for a
recurrence set.
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Value Type: The default value type for this property is DATE-TIME.
The value type MAY be reset to DATE or PERIOD.
Conformance: The property MAY only appear within the "VEVENT",
"VTODO", "VJOURNAL" or "VTIMEZONE" calendar components.
Description: This property MAY appear along with the "RRULE" property
to define an aggregate set of repeating occurrences. When they both
appear in an iCalendar object, the recurring events are defined by
the union of occurrences defined by both the "RDATE" and "RRULE".
The recurrence dates, 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", "EXDATE" and "EXRULE" properties contained within the
iCalendar object. The "DTSTART" property defines the first instance
in the recurrence set. Multiple instances of the "RRULE" and "EXRULE"
properties MAY also be specified to define more sophisticated
recurrence sets. The final recurrence set is generated by gathering
all of the start date-times generated by any of the specified "RRULE"
and "RDATE" properties, and excluding any start date and times which
fall within the union of start date and times generated by any
specified "EXRULE" and "EXDATE" properties. This implies that start
date and times within exclusion related properties (i.e., "EXDATE"
and "EXRULE") 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.
Only the "VALUE" and "TZID" property parameters MAY be specified on
this property. The "TZID" property parameter MAY only be specified
when the value type is DATE-TIME.
Format Definition: The property is defined by the following notation:
rdate = "RDATE" [rdtparam] ":" [WSP] rdtval
*("," [WSP] rdtval) CRLF
rdtparam = [";" [WSP] "VALUE" "=" "DATE-TIME"]
[";" [WSP] "TZID" "=" paramtext]
rdtparam =/ ";" [WSP] "VALUE" "=" "DATE"
rdtparam =/ ";" [WSP] "VALUE" "=" "PERIOD"
rdtval = date-time / date / period
;Value MUST match value type
Example: The following are examples of this property:
RDATE:19970714T123000Z
RDATE;TZID=EST:19970714T083000
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RDATE;VALUE=PERIOD:19960403T020000Z/19960403T040000Z,
19960404T010000Z/PT3H
RDATE;VALUE=DATE:19970101,19970120,19970217,19970421
19970526,19970704,19970901,19971014,19971128,19971129,19971225
4.8.5.4 Recurrence Rule
Property Name: RRULE
Purpose: This property defines a rule or repeating pattern for a
recurring events, to-dos, or time zone definitions.
Value Type: RECUR
Conformance: This property MAY be specified one or more times in
recurring "VEVENT", "VTODO" and "VJOURNAL" calendar components. It
MAY also be specified once in the "VTIMEZONE" calendar component.
Description: The recurring 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", "EXDATE" and "EXRULE" properties contained
within the iCalendar object. The "DTSTART" property defines the first
instance in the recurrence set. Multiple instances of the "RRULE" and
"EXRULE" properties MAY also be specified to define more
sophisticated recurrence sets. The final recurrence set is generated
by gathering all of the start date-times generated by any of the
specified "RRULE" and "RDATE" properties, and excluding any start
date and times which fall within the union of start date and times
generated by any specified "EXRULE" and "EXDATE" properties. This
implies that start date and times within exclusion related properties
(i.e., "EXDATE" and "EXRULE") 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.
The "DTSTART" and "DTEND" property pair or "DTSTART" and "DURATION"
property pair, specified within the iCalendar object defines the
first instance of the recurrence. When used with a recurrence rule,
the "DTSTART" and "DTEND" properties MUST be specified in local time
and the appropriate set of "VTIMEZONE" calendar components MUST be
included. For detail on the usage of the "VTIMEZONE" calendar
component, see the "VTIMEZONE" calendar component definition.
Any duration associated with the iCalendar object applies to all
members of the generated recurrence. Any modified duration for
specific recurrences would have to be explicitly specified using the
"RDATE" property.
No property parameters MAY be specified on this property.
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Format Definition: This property is defined by the following
notation:
rrule = "RRULE" ":" [WSP] recur CRLF
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 9AM EDT)September 2-11
Daily until 12/24/97:
DTSTART;TZID=America-New York:19970902T090000
RRULE:FREQ=DAILY;UNTIL=19971224T000000Z
==> (1997 9AM EDT)September 2-30;October 1-25
(1997 9AM EST)October 26-31;November 1-30;December 1-23
Every other day - forever:
DTSTART;TZID=America-New York:19970902T090000
RRULE:FREQ=DAILY;INTERVAL=2
==> (1997 9AM EDT)September2,4,6,8...24,26,28,30;
October 2,4,6...20,22,24
(1997 9AM EST)October 26,28,30;November 1,3,5,7...25,27,29;
Dec 1,3,...
Every 10 days, 5 occurrences:
DTSTART;TZID=America-New York:19970902T090000
RRULE:FREQ=DAILY;INTERVAL=10;COUNT=5
==> (1997 9AM EDT)September 2,12,22;October 2,12
Everyday in January, for 3 years:
DTSTART;TZID=America-New York:19980101T090000
RRULE;TZID=America-New York:FREQ=YEARLY;UNTIL:20000131T090000;
BYMONTH=1;BYDAY=SU,MO,TU,WE,TH,FR,SA
or
RRULE;TZID=America-New York:FREQ=DAILY;UNTIL:20000131T090000;
BYMONTH=1
==> (1998 9AM EDT)January 1-31
(1999 9AM EDT)January 1-31
(2000 9AM EDT)January 1-31
Weekly for 10 occurrences
DTSTART;TZID=America-New York:19970902T090000
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RRULE:FREQ=WEEKLY;COUNT=10
==> (1997 9AM EDT)September 2,9,16,23,30;October 7,14,21
(1997 9AM EST)October 28;November 4
Weekly until 12/24/94
DTSTART;TZID=America-New York:19970902T090000
RRULE:FREQ=WEEKLY;UNTIL=19971224T000000Z
==> (1997 9AM EDT)September 2,9,16,23,30;October 7,14,21
(1997 9AM 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 9AM EDT)September 2,16,30;October 14
(1997 9AM EST)October 28;November 11,25;December 9,23
(1998 9AM EST)January 6,20;February
...
Weekly on Tuesday and Thursday for 5 weeks:
DTSTART;TZID=America-New York:19970902T090000
RRULE;TZID=America-New York:FREQ=WEEKLY;UNTIL=19971007T000000;
WKST=SU;BYDAY=TU,TH
or
RRULE:FREQ=WEEKLY;COUNT=10;WKST=SU;BYDAY=TU,TH
==> (1997 9AM EDT)September 2,4,9,11,16,18,23,25,30;October 2
Every other week on Monday, Wednesday and Friday until 12/24/97, but
starting on Tuesday, 9/2/97:
DTSTART;TZID=America-New York:19970902T090000
RRULE;TZID=America-New York:FREQ=WEEKLY;INTERVAL=2;UNTIL=
19971224T000000;WKST=SU;BYDAY=MO,WE,FR
==> (1997 9AM EDT)September 2,3,5,15,17,19,29;October 1,3,13,15,17
(1997 9AM EST)October 27,29,31;November 10,12,14,24,26,28;
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 9AM EDT)September 2,4,16,18,30;October 2,14,16
Monthly on the 1st Friday for ten occurrences:
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DTSTART;TZID=America-New York:19970905T090000
RRULE:FREQ=MONTHLY;COUNT=10;BYDAY=1FR
==> (1997 9AM EDT)September 5;October 3
(1997 9AM EST)November 7;Dec 5
(1998 9AM EST)January 2;February 6;March 6;April 3
(1998 9AM EDT)MAY 1;June 5
Monthly on the 1st Friday until 12/24/94:
DTSTART;TZID=America-New York:19970905T090000
RRULE:FREQ=MONTHLY;UNTIL=19971224T000000Z;BYDAY=1FR
==> (1997 9AM EDT)September 5;October 3
(1997 9AM EST)November 7;December 5
Every other month on the 1st 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 9AM EDT)September 7,28
(1997 9AM EST)November 2,30
(1998 9AM EST)January 4,25;March 1,29
(1998 9AM 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 9AM EDT)September 22;October 20
(1997 9AM EST)November 17;December 22
(1998 9AM EST)January 19;February 16
Monthly on the third to the last day of the month, forever:
DTSTART;TZID=America-New York:19970928T090000
RRULE:FREQ=MONTHLY;BYMONTHDAY=-3
==> (1997 9AM EDT)September 28
(1997 9AM EST)October 29;November 28;December 29
(1998 9AM 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 9AM EDT)September 2,15;October 2,15
(1997 9AM EST)November 2,15;December 2,15
(1998 9AM EST)January 2,15
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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 9AM EDT)September 30;October 1
(1997 9AM EST)October 31;November 1,30;December 1,31
(1998 9AM 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 9AM EDT)September 10,11,12,13,14,15
(1999 9AM 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 9AM EDT)September 2,9,16,23,30
(1997 9AM EST)November 4,11,18,25
(1998 9AM EST)January 6,13,20,27;March 3,10,17,24,31
...
Yearly in June and July for 10 occurrences:
DTSTART;TZID=America-New York:19970610T090000
RRULE:FREQ=YEARLY;COUNT=10;BYMONTH=6,7
==> (1997 9AM EDT)June 10;July 10
(1998 9AM EDT)June 10;July 10
(1999 9AM EDT)June 10;July 10
(2000 9AM EDT)June 10;July 10
(2001 9AM 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 9AM EST)March 10
(1999 9AM EST)January 10;February 10;March 10
(2001 9AM EST)January 10;February 10;March 10
(2003 9AM EST)January 10;February 10;March 10
Every 3rd year on the 1st, 100th and 200th day for 10 occurrences:
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DTSTART;TZID=America-New York:19970101T090000
RRULE:FREQ=YEARLY;INTERVAL=3;COUNT=10;BYYEARDAY=1,100,200
==> (1997 9AM EST)January 1
(1997 9AM EDT)April 10;July 19
(2000 9AM EST)January 1
(2000 9AM EDT)April 9;July 18
(2003 9AM EST)January 1
(2003 9AM EDT)April 10;July 19
(2006 9AM EST)January 1
Every 20th Monday of the year, forever:
DTSTART;TZID=America-New York:19970519T090000
RRULE:FREQ=YEARLY;BYDAY=20MO
==> (1997 9AM EDT)MAY 19
(1998 9AM EDT)MAY 18
(1999 9AM EDT)MAY 17
...
Monday of Week No. 20, forever:
DTSTART;TZID=America-New York:19970512T090000
RRULE:FREQ=YEARLY;BYWEEKNO=20;BYDAY=MO
==> (1997 9AM EDT)MAY 12
(1998 9AM EDT)MAY 11
(1999 9AM EDT)MAY 17
...
Every Thursday in March, forever:
DTSTART;TZID=America-New York:19970313T090000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=TH
==> (1997 9AM EST)March 13,20,27
(1998 9AM EST)March 5,12,19,26
(1999 9AM EST)March 4,11,18,25
...
Every Thursday, but only during summer months, forever:
DTSTART;TZID=America-New York:19970605T090000
RRULE:FREQ=YEARLY;BYDAY=TH;BYMONTH=6,7,8
==> (1997 9AM EDT)June 5,12,19,26;July 3,10,17,24,31;
August 7,14,21,28
(1998 9AM EDT)June 4,11,18,25;July 2,9,16,23,30;
August 6,13,20,27
(1999 9AM EDT)June 3,10,17,24;July 1,8,15,22,29;
August 5,12,19,26
...
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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 9AM EST)February 13;March 13;November 13
(1999 9AM EDT)August 13
(2000 9AM EDT)October 13
...
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 9AM EDT)September 13;October 11
(1997 9AM EST)November 8;December 13
(1998 9AM EST)January 10;February 7;March 7
(1998 9AM EDT)April 11;MAY 9;June 13...
...
Every four 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 9AM EST)November 5
(2000 9AM EST)November 7
(2004 9AM EST)November 2
...
The 3rd 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 9AM EDT)September 4;October 7
(1997 9AM EST)November 6
The 2nd to last weekday of the month:
DTSTART;TZID=America-New York:19970929T090000
RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-2
==> (1997 9AM EDT)September 29
(1997 9AM EST)October 30;November 27;December 30
(1998 9AM EST)January 29;February 26;March 30
...
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Every 3 hours from 9AM to 5PM on a specific day:
DTSTART;TZID=America-New York:19970902T090000
RRULE;TZID=America-New York:FREQ=HOURLY;INTERVAL=3;
UNTIL=19970902T170000
==> (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 9AM to 4:40PM 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)Aug 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
4.8.6 Alarm Component Properties
The following properties specify alarm information in calendar
components.
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4.8.6.1 Alarm Type
Property Name: ALARM-TYPE
Purpose: This property defines the type of alarm.
Value Type: TEXT
Conformance: This property MUST be specified once within a "VALARM"
calendar component.
Description: Each "VALARM" calendar component is of a particular
type. This property specifies the alarm type. Only the "LANGUAGE"
property parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
alarm-type = "ALARM-TYPE" [almtypparam] ":" [WSP] almtypvalue CRLF
almtypparam = ";" [WSP] languageparm
almtypvalue = "AUDIO" / "DISPLAY" / "EMAIL" / "PROCEDURE"
/ iana-token / x-name
Example: The following are examples of this property in a "VALARM"
calendar component:
CATEGORIES:AUDIO,DISPLAY
CATEGORIES:PROCEDURE
4.8.6.2 Repeat Count
Property Name: REPEAT
Purpose: This property defines the number of time the alarm should be
repeated, after the initial trigger.
Value Type: INTEGER
Conformance: This property MAY only be specified in a "VALARM"
calendar component.
Description: If the alarm triggers more than once, then this property
MUST be specified; along with the "DURATION" property.
No property parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
repeatcnt = "REPEAT" ":" [WSP] integer CRLF
;Default is "0", zero.
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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
4.8.6.3 Trigger
Property Name: TRIGGER
Purpose: This property specifies when an alarm will trigger.
Value Type: The default value type is DURATION. The value type MAY BE
reset to a DATE-TIME value type.
Conformance: This property MUST be specified within the "VALARM"
calendar component.
Description: Within the "VALARM" calendar component, this property
defines when the 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
that the alarm is associated with. 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
before the associated start or end of the event or to-do. An alarm
with a negative duration is triggered after the associated start or
end of the event or to-do.
This parameter is not valid if the value type of the property is
reset to DATE-TIME, in order to specify an absolute trigger for the
alarm. If a value type of DATE-TIME is specified, then the 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 "DSTART" 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 "DSTART" and "DURATION' properties must be present in the
associated "VTODO" calendar component.
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Alarms specified in an event or to-do that is defined solely in terms
of a DATE value type will be triggered relative to midnight on the
day prior to the specified date. For example, if "DTSTART:19980205,
then the a duration trigger will be relative to 19980204T240000Z.
Only the "VALUE" and "TZID" property parameters and property-specific
"RELATED" parameter MAY be specified on this property. The "TZID"
property parameter MAY only be specified when the value type is DATE-
TIME.
Format Definition: The property is defined by the following notation:
trigger = "TRIGGER" (trigrel / trigabs)
trigrel = ([";" [WSP] "VALUE" "=" "DURATION"]
";" [WSP] "RELATED" "=" ("START" / "END"))
":" [WSP] (["+"] / "-") duration
trigabs = (";" [WSP] "VALUE" "=" "DATE-TIME"
":" [WSP] date-time)
Example: A trigger set 15 minutes relative to the start of the event
or to-do.
TRIGGER:P15M
A trigger set 5 minutes relative to the end of the event or to-do.
TRIGGER;RELATED=END:P5M
A trigger set to an absolute date/time.
TRIGGER;VALUE=DATE-TIME:19980101T050000Z
4.8.7 Change Management Component Properties
The following properties specify change management information in
calendar components.
4.8.7.1 Date/Time Created
Property Name: CREATED
Purpose: This property specifies the date and time that the calendar
information was created in the calendar user agent.
Value Type: DATE-TIME
Conformance: The property MAY be specified in any of the calendar
components. The property MAY only be specified once.
Description: The date and time is a UTC value.
No property parameters MAY be specified on this property.
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Format Definition: The property is defined by the following notation:
created = "CREATED" ":" [WSP] date-time CRLF
Example: The following is an example of this property:
CREATED:19960329T133000Z
4.8.7.2 Date/Time Stamp
Property Name: DTSTAMP
Purpose: The property indicates the date/time that the instance of
the iCalendar object was created.
Value Type: DATE-TIME
Conformance: This property MUST be included in the "VEVENT", "VTODO",
"VJOURNAL" and "VFREEBUSY" calendar components.
Description: The value must be specified in the UTC time format.
This property is also useful to protocols such as [IMIP] that have
inherent latency issues with the delivery of content. This property
will assist in the proper sequencing of messages containing iCalendar
objects.
This property is different than the "CREATED" and "LAST-MODIFIED"
properties. These two properties are used to specify when the
calendar service information was created and last modified. This is
different than when the iCalendar object representation of the
calendar service information was created or last modified.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
dtstamp = "DTSTAMP" ":" [WSP] date-time CRLF
Example:
DTSTAMP:19971210T080000Z
4.8.7.3 Last Modified
Property Name: LAST-MODIFIED
Purpose: The property specifies the date and time that the
information associated with the calendar component was last revised.
Value Type: DATE-TIME
Conformance: This property MAY be specified in the "EVENT", "VTODO",
"VJOURNAL" or "VFREEBUSY" calendar components.
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Description: The property value MUST be specified in the UTC time
format.
No property parameters MAY be specified on this property.
Format Definition: The property is defined by the following notation:
last-mod = "LAST-MODIFIED" ":" [WSP] date-time CRLF
Example: The following is are examples of this property:
LAST-MODIFIED:19960817T133000Z
4.8.7.4 Sequence Number
Property Name: SEQUENCE
Purpose: This property defines the revision sequence of the calendar
component used in a request.
Value Type: INTEGER
Conformance: The property MAY only be specified in a "VEVENT",
"VTODO", "VJOURNAL" or "VFREEBUSY" calendar component.
Description: This property is needed to properly handle the receipt
and processing of a sequence of calendar components that have been
delivered out of order. Such is the case for store-and-forward based
transports. The first request is created with a sequence number of
"0" (ASCII decimal 48). It is incremented each time the ORGANIZER or
OWNER issues a revision to the request. The sequence number MUST be
monotonically incremented when one of the following properties in a
calendar component is changed:
. "DTSTART"
. "DTEND"
. "DUE"
. "RDATE"
. "RRULE"
. "EXDATE"
. "EXRULE"
No property parameter MAY be specified on this property.
Format Definition: The property is defined by the following notation:
seq = "SEQUENCE" ":" [WSP] integer CRLF
;Default is "0".
Example: The following is an example of this property:
SEQUENCE:1
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4.8.8 Miscellaneous Component Properties
The following properties specify information about a number of
miscellaneous features of calendar components.
4.8.8.1 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: TEXT
Conformance: This property MAY 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 names that have the
prefix text of "X-" (the two character sequence: LATIN CAPITAL LETTER
X character followed by the HYPEN-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
MAY ignore them.
At present, there is no registration authority for names of extension
properties and property parameters. The data type for this property
is TEXT. Optionally, the data type MAY be any of the other valid data
types.
Any of the general property parameters MAY be specified on this
property.
Format Definition: The property is defined by the following notation:
extension = "X-" [vendorid] "-" text *(";" [WSP] param) ":"
[WSP] value-list CRLF
; Lines longer than 75 characters should be folded
vendorid = 3*char ;Vendor identification prefix text
Example: The following might be the ABC vendor's extension for an
audio-clip form of subject property:
X-ABC-MMSUBJ;TYPE=wave; VALUE=URI: http://load.noise.org/mysubj.wav
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4.8.8.2 Request Status
Property Name: REQUEST-STATUS
Purpose: This property defines the status code returned for a
scheduling request.
Value Type: TEXT
Conformance: The property MAY be specified in a "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 data
type for this property is TEXT.
The value consists of a short return status, a longer return status
description, and optionally the offending data. The components of the
value are separated by the SEMICOLON character (ASCII decimal 59).
The short return status is a PERIOD character (ASCII decimal 46)
separated 3-tuple of integers. For example, "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 Return | Longer Return Status Description |
| Status Code | |
|==============+===============================================|
| 1.xx | Preliminary success. This class of status |
| | of status code indicates that the request has |
| | request has been initially processed but that |
| | completion is pending. |
|==============+===============================================|
| 2.xx | Successful. This class of status code |
| | indicates that the request was completed |
| | successfuly. However, the exact status code |
| | MAY 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.|
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| | Some sort of error occurred within the |
| | calendaring and scheduling service, not |
| | directly related to the request itself. |
|==============+===============================================|
Only the "LANGUAGE" property parameter MAY be specified on this
property.
Format Definition: The property is defined by the following notation:
rstatus = "REQUEST-STATUS" [rstatparam] ":" [WSP]
statcode ";" [WSP] statdesc [";" [WSP] extdata]
rstatparam = ";" [WSP] languageparm
statcode = 1*DIGIT *("." 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
(Note: The BACKSLASH character escapement of separator characters in
the property because it has a text value type):
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@host.com
5 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
8:00 AM EDT, September 18, 1996 and end at 6:00 PM EDT, September 20,
1996.
BEGIN:VCALENDAR
PRODID:-//xyz Corp//NONSGML PDA Calendar Verson 1.0//EN
VERSION:2.0
BEGIN:VEVENT
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DTSTAMP:19960704T120000Z
UID:uid1@host.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 begin
at 8:30 AM EST on March 12, 1998 and end 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:Eastern US
BEGIN:STANDARD
DTSTART:19981025T020000
RDATE:19981025T020000
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19990404T020000
RRULE:19990404T020000
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
DTSTAMP:19980309T231000Z
UID:guid-1.host1.com
ORGANIZER;ROLE=CHAIR:mrbig@host.com
ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT;TYPE=GROUP:
MAILTO:employee-A@host.com
DESCRIPTION:Project XYZ Review Meeting
CATEGORIES:MEETING
CLASS:PUBLIC
CREATED:19980309T130000Z
SUMMARY:XYZ Project Review
DTSTART;TZID=EST:19980312T083000
DTEND;TZID=EST:19980312T0930
LOCATION:1CP Conference Room 4350
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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@host1.com
FROM:jdoe@host1.com
MIME-VERSION:1.0
MESSAGE-ID:<id3@host1.com>
CONTENT-TYPE:text/calendar
BEGIN:VCALENDAR
METHOD:xyz
VERSION:2.0
PRODID:-//ABC Corporation//NONSGML My Product//EN
BEGIN:VEVENT
DTSTAMP:19970324T1200Z
SEQUENCE:0
UID:uid3@host1.com
ORGANIZER:jdoe@host1.com
ATTENDEE;RSVP=TRUE:MAILTO:jsmith@host1.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
ATTACH:file:///xyzCorp.com/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@host1.com
ORGANIZER:unclesam@us.gov
ATTENDEE;ATTSTAT=ACCEPTED;ATTSTAT=ACCEPTED:MAILTO:jqpublic@host.com
DUE:19980415T235959
STATUS:NEEDS-ACTION
SUMMARY:Submit Income Taxes
BEGIN:VALARM
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ALARM-TYPE:AUDIO
TRIGGER:19980403T120000
ATTACH:http://host.com/pub/audio-files/ssbanner.wav
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@host1.com
STATUS:DRAFT
CLASS:PUBLIC
CATEGORY:Project Report, XYZ, Weekly Meeting
DESCRIPTION:Project xyz Review Meeting Minutes\n
Agenda\n1. Review of project version 1.0 requirements.\n2.
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
www.host.com/calendar/busytime/jsmith.ifb.
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//RDU Software//NONSGML HandCal//EN
BEGIN:VFREEBUSY
ATTENDEE:jsmith@host.com
DTSTART:19980313T141711Z
DTEND:19980410T141711Z
FREEBUSY:19980314T233000Z/19980315T003000Z
FREEBUSY:19980316T153000Z/19980316T163000Z
FREEBUSY:19980318T030000Z/19980318T040000Z
URL:http://www.host.com/calendar/busytime/jsmith.ifb
END:VFREEBUSY
END:VCALENDAR
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6 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 character SHOULD be folded.
2. A calendar entry with a "DTSTART" property but no "DTEND" property
- The event does not take up any time. It is intended to represent
an event that is associated with a given calendar date and time of
day, such as an anniversary. Since the event does not take up any
time, it MUST NOT be used to record busy time no matter what the
value for the "TRANSP" property.
3. When the "DTSTART" and "DTEND", for "VEVENT", "VJOURNAL" and
"VFREEBUSY" calendar components, and "DTSTART" and "DUE", for
"VTODO" calendar components, have the same value data type (e.g.,
DATE-TIME), they should specify values in the same time format
(e.g., UTC time format).
4. A combination of "RRULE" and "RDATE" properties that produces more
than one instance for a given date/time - Only one recurrence can
occur on a given date/time interval. Just one instance for the
date/time is recorded.
5. A particular iCalendar object method that specifies "ATTENDEE"
properties with the "MEMBER" property parameter, for which the
recipient has multiple memberships - Recipient should reply to
only the first "MEMBER" property parameter value that it can
match.
6. An implementation MAY truncate a "SUMMARY" property value to 255
characters.
7. 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.
7 Registration of Content Type Elements
This section provide the process for registration of MIME Calendaring
and Scheduling Content Type iCalendar object methods and new or
modified properties.
7.1 Registration of New and Modified iCalendar Object Methods
New MIME Calendaring and Scheduling Content Type iCalendar object
methods are registered by the publication of an IETF Request for
Comment (RFC). Changes to an iCalendar object method are registered
by the publication of a revision of the RFC defining the method.
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7.2 Registration of New Properties
This section defines procedures by which new properties or enumerated
property values for the MIME Calendaring and Scheduling Content Type
can be registered with the IANA. Note that non-IANA properties MAY be
used by bilateral agreement, provided the associated properties names
follow the "X-" convention.
The procedures defined here are designed to allow public comment and
review of new properties, while posing only a small impediment to the
definition of new properties.
Registration of a new property is accomplished by the following
steps.
7.2.1 Define the property
A property is defined by completing the following template.
To: ietf-calendar@imc.org
Subject: Registration of text/calendar MIME property XXX
Property name:
Property purpose:
Property data type(s):
Property encoding:
Property special notes (optional):
Intended usage: (one of COMMON, LIMITED USE or OBSOLETE)
The meaning of each field in the template is as follows.
Property name: The name of the property, as it will appear in the
body of an text/calendar MIME Content-Type "property: value" line to
the left of the colon ":".
Property purpose: The purpose of the property (e.g., to indicate a
delegate for the event or to-do, etc.). Give a short but clear
description.
Property data type(s): Any of the valid data types for the property
value needs to be specified. The default data type also needs to be
specified. If a new data type is specified, it needs to be declared
in this section.
Property special notes: Any special notes about the property, how it
is to be used, etc.
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7.2.2 Post the Property definition
The property description MUST be posted to the new property
discussion list, ietf-calendar@imc.org.
7.2.3 Allow a comment period
Discussion on the new property MUST be allowed to take place on the
list for a minimum of two weeks. Consensus MUST be reached on the
property before proceeding to the next step.
7.2.4 Submit the property for approval
Once the two-week comment period has elapsed, and the proposer is
convinced consensus has been reached on the property, the
registration application should be submitted to the Method Reviewer
for approval. The Method Reviewer is appointed to the Application
Area Directors and MAY either accept or reject the property
registration. An accepted registration should be passed on by the
Method Reviewer to the IANA for inclusion in the official IANA method
registry. The registration MAY be rejected for any of the following
reasons. 1) Insufficient comment period; 2) Consensus not reached; 3)
Technical deficiencies raised on the list or elsewhere have not been
addressed. The Method Reviewer's decision to reject a property MAY be
appealed by the proposer to the IESG, or the objections raised can be
addressed by the proposer and the property resubmitted.
7.3 Property Change Control
Existing properties MAY be changed using the same process by which
they were registered.
1. Define the change
2. Post the change
3. Allow a comment period
4. Submit the property for approval
Note that the original author or any other interested party MAY
propose a change to an existing property, but that such changes
should only be proposed when there are serious omissions or errors in
the published memo. The Method Reviewer MAY object to a change if it
is not backwards compatible, but is not required to do so.
Property definitions can never be deleted from the IANA registry, but
properties which are no longer believed to be useful can be declared
OBSOLETE by a change to their "intended use" field.
8 References
The following document are referred to within this memo.
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[ICMS] "Internet Calendaring Model Specification", Internet-Draft,
July 1997, ftp://ftp.ietf.org/internet-drafts/draft-ietf-calsch-mod-
03.txt.
[IMIP] "iCalendar Message-based Interoperability Protocol (IMIP)",
Internet Draft, February 1998, http://www.imc.org/draft-ietf-calsch-
imip-04.txt.
[ISO 8601] ISO 8601, "Data elements and interchange formats_
Information interchange--Representation of dates and times",
International Organization for Standardization, June, 1988. This
standard is also addressed by the Internet Draft document
ftp://ds.internic.net/internet-drafts/draft-newman-datetime-00.txt.
[ISO 9070] ISO/IEC 9070, "Information Technology_SGML Support
Facilities--Registration Procedures for Public Text Owner
Identifiers", Second Edition, International Organization for
Standardization, April, 1991.
[ITIP] "iCalendar Transport-Independent Interoperability Protocol
(iTIP) : Scheduling Events, Busy Time, To-dos and Journal Entries ",
Internet-Draft, February 1998, http://www.imc.org/draft-ietf-calsch-
itip-03.txt.
[MIME DIR] Howes, T., Smith, M., "A MIME Content-Type for Directory
Information", Internet-draft-ietf-asid-mime-direct-07.txt, November,
1997.
[RFC 822] Crocker, D., "Standard for the Format of ARPA Internet Text
Messages", STD 11, RFC 822, August 1982.
[RFC 1738] Berners-Lee, T., Masinter, L., McCahill, M., "Uniform
Resource Locators (URL)", RFC 1738, December 1994.
[RFC 1766] Alvestrand, H., "Tags for the Identification of
Languages", March 1995.
[RFC 1872] Levinson, E., "The MIME Multipart/Related Content-type,"
RFC 1872, December 1995.
[RFC 1983] "Internet Users' Glossary", RFC 1983, August 1996.
[RFC 2045] Freed, N., Borenstein, N., " Multipurpose Internet Mail
Extensions (MIME) - Part One: Format of Internet Message Bodies", RFC
2045, November 1996.
[RFC 2046] Freed, N., Borenstein, N., " Multipurpose Internet Mail
Extensions (MIME) - Part Two: Media Types", RFC 2046, November 1996.
[RFC 2047] Moore, K., "Multipurpose Internet Mail Extensions (MIME) -
Part Three: Message Header Extensions for Non-ASCII Text", RFC 2047,
November 1996.
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[RFC 2048] Freed, N., J. Klensin, J. Postel, "Multipurpose Internet
Mail Extensions (MIME) - Part Four: Registration Procedures", RFC
2048, January 1997.
[RFC 2111] "Content-ID and Message-ID Uniform Resource Locators", RFC
2111, March 1997.
[RFC 2119] "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, March 1997.
[UTF-8] "UTF-8, a transformation format of Unicode and ISO
10646",Internet-Draft, July,1996, ftp://ftp.ietf.org/internet-
drafts/draft-yergeau-utf8-01.txt.
[VCARD] Internet Mail Consortium, "vCard - The Electronic Business
Card Version 2.1", http://www.imc.org/pdi/vcard-21.txt, September
18, 1996.
[VCAL] Internet Mail Consortium, "vCalendar - The Electronic
Calendaring and Scheduling Exchange Format",
http://www.imc.org/pdi/vcal-10.txt, September 18, 1996.
[XAPIA] "XAPIA CSA, Calendaring and Scheduling Application
Programming Interface (CSA) Version 1.0", X.400 API Association,
November 15, 1994.
9 Acknowledgments
A hearty thanks to the IETF Calendaring and Scheduling Working Group
and also the following individuals who have participated in the
drafting, review and discussion of this memo:
Roland Alden, Harald T. Alvestrand, Eric Berman, Denis Bigorgne, John
Binici, Bill Bliss, Philippe Boucher, Steve Carter, Andre
Courtemanche, Dave Crocker, David Curley, Alec Dun, John Evans, Ross
Finlayson, Randell Flint, Ned Freed, Patrik Falstrom, Chuck
Grandgent, Mark Handley, Steve Hanna, Paul B. Hill, Paul Hoffman,
Ross Hopson, Mark Horton, Bruce Kahn, C. Harald Koch, Ryan Jansen,
Don Lavange, Theodore Lorek, Steve Mansour, Skip Montanaro, Keith
Moore, Cecil Murray, Chris Newman, John Noerenberg, Ralph Patterson,
Pete Resnick, Keith Rhodes, Robert Ripberger, John Rose, Doug Royer,
Andras Salamar, Ted Schuh, Vinod Seraphin, Derrick Shadel, Ken Shan,
Andrew Shuman, Steve Silverberg, William P. Spencer, John Sun, Mark
Towfiq, Yvonne Tso, Robert Visnov, James L. Weiner, Mike Weston,
William Wyatt.
10 Author's Address
The following address information is provided in a MIME-VCARD,
Electronic Business Card, format.
The authors of this draft are:
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BEGIN:VCARD
VERSION:2.1
FN:Frank Dawson
ORG:Lotus Development Corporation
ADR;WORK;POSTAL;PARCEL:;6544 Battleford Drive;
Raleigh;NC;27613-3502;USA
TEL;WORK;MSG:+1-919-676-9515
TEL;WORK;FAX:+1-919-676-9564
EMAIL;INTERNET;PREF:Frank_Dawson@Lotus.com
EMAIL;INTERNET:fdawson@earthlink.net
URL:http://home.earthlink.net/~fdawson
END:VCARD
BEGIN:VCARD
VERSION:2.1
FN:Derik Stenerson
ORG:Microsoft Corporation
ADR;WORK;POSTAL;PARCEL:;One Microsoft Way;
Redmond;WA;98052-6399;USA
TEL;WORK;MSG:+1-425-936-5522
TEL;WORK;FAX:+1-425-936-7329
EMAIL;INTERNET:deriks@Microsoft.com
END:VCARD
The iCalendar object is a result of the work of the Internet
Engineering Task Force Calendaring and Scheduling Working Group. The
chairman of that working group is:
BEGIN:VCARD
VERSION:2.1
FN:Anik Ganguly
ORG:OnTime, Inc.
ADR;WORK;POSTAL;PARCEL:10 Floor;21700 Northwestern Highway;
Southfield;MI;48075;USA
TEL;WORK;MSG:+1-248-559-5955
TEL;WORK;FAX:+1-248-559-5034
EMAIL;INTERNET:anik@ontime.com
END:VCARD
11 Full Copyright Statement
"Copyright (C) The Internet Society (date). All Rights Reserved.
This document and translations of it MAY be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implmentation MAY be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself MAY not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process MUST be
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followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Dawson/Stenerson 111 Expires September 1998
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