Network Working Group Frank Dawson, Lotus
Internet Draft Derik Stenerson, Microsoft
November 21, 1997
Expires May 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 a 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 and to-do 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
or using HTTP. In addition, the content type is useful as an object
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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. This memo is based on the
calendaring and scheduling model defined in []. The document is also
the basis for the calendaring and scheduling interoperability
protocol defined in [ITIP].
This memo also includes the format for defining 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.
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Table of Contents
1. Introduction........................................................5
2. Basic Grammar and Conventions.......................................5
2.1 Formatting Conventions ...........................................6
2.2 Related Memos ....................................................7
3. TEXT/CALENDAR Registration Information..............................7
4. iCalendar Object Specification......................................9
4.1 Content Considerations ...........................................9
4.1.1 Content Lines ................................................10
4.1.2 List and Field Separators ....................................12
4.1.3 Multiple Values ..............................................13
4.1.4 Binary Content ...............................................13
4.1.5 Property Parameters ..........................................13
4.1.6 Alternate Text Representation ................................14
4.1.7 Character Set ................................................14
4.1.8 Inline Encoding ..............................................15
4.1.9 Language .....................................................15
4.1.10 Value Data Types ............................................15
4.2 iCalendar object ................................................25
4.3 Property ........................................................26
4.4 Calendar Components .............................................26
4.4.1 Event Component ..............................................26
4.4.2 To-do Component ..............................................28
4.4.3 Journal Component ............................................29
4.4.4 Free/Busy Component ..........................................30
4.4.5 Alarm Component ..............................................31
4.4.6 Timezone Component ...........................................33
4.5 Calendar Properties .............................................37
4.5.1 Calendar Scale ...............................................37
4.5.2 Method .......................................................37
4.5.3 Product Identifier ...........................................38
4.5.4 Source .......................................................38
4.5.5 Source Name ..................................................39
4.5.6 Version ......................................................39
4.6 Component Properties ............................................40
4.6.1 Attachment ...................................................40
4.6.2 Attendee .....................................................40
4.6.3 Categories ...................................................43
4.6.4 Classification ...............................................44
4.6.5 Comment ......................................................44
4.6.6 Contact ......................................................45
4.6.7 Date/Time Completed ..........................................45
4.6.8 Date/Time Created ............................................46
4.6.9 Date/Time Due ................................................46
4.6.10 Date/Time End ...............................................46
4.6.11 Date/Time Stamp .............................................47
4.6.12 Date/Time Start .............................................47
4.6.13 Daylight ....................................................48
4.6.14 Description .................................................48
4.6.15 Duration ....................................................49
4.6.16 Exception Date/Times ........................................50
4.6.17 Exception Rule ..............................................50
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4.6.18 Free/Busy Time ..............................................51
4.6.19 Geographic Position .........................................52
4.6.20 Last Modified ...............................................53
4.6.21 Location ....................................................53
4.6.22 Percent Complete ............................................54
4.6.23 Priority ....................................................54
4.6.24 Recurrence Date/Times .......................................55
4.6.25 Recurrence ID ...............................................56
4.6.26 Recurrence Rule .............................................57
4.6.27 Related To ..................................................64
4.6.28 Repeat Count ................................................65
4.6.29 Request Status ..............................................66
4.6.30 Resources ...................................................67
4.6.31 Sequence Number .............................................68
4.6.32 Status ......................................................68
4.6.33 Summary .....................................................69
4.6.34 Time Transparency ...........................................69
4.6.35 Time Zone Name ..............................................70
4.6.36 Time Zone Offset ............................................70
4.6.37 Uniform Resource Locator ....................................70
4.6.38 Unique Identifier ...........................................71
4.6.39 Non-standard Properties .....................................72
5. Recommended Practices..............................................72
6. Registration of Content Type Elements..............................73
6.1 Registration of New and Modified iCalendar object Methods .......73
6.2 Registration of New Properties ..................................73
6.2.1 Define the property ..........................................73
6.2.2 Post the Property definition .................................74
6.2.3 Allow a comment period .......................................74
6.2.4 Submit the property for approval .............................74
6.3 Property Change Control .........................................75
7. File extension.....................................................75
8. Macintosh File Type Code...........................................75
9. References.........................................................75
10. Acknowledgments...................................................77
11. Author's Address..................................................77
12. iCalendar object Examples.........................................78
13. Full Copyright Statement..........................................80
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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 groupware 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 or a Group Scheduling product.
The calendaring and scheduling model implemented by this memo is
defined in the [ICMS].
The 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 definition of a calendaring and scheduling interoperability
protocol is the subject of another memo [ITIP].
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.
The memo also includes a formal grammar for the content type to aid
in 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].
This memo makes use of both a descriptive prose and a more formal
notation for defining the calendaring and scheduling format.
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The notation used in this memo is the augmented BNF notation of [RFC
822]. 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. In order
to refer to elements of the calendaring and scheduling model [ICMS],
core object (this memo) or interoperability protocol [ITIP] in this
memo 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,
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
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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;
[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: method
The "method" parameter is used to convey the iCalendar object
method to which the calendaring and scheduling information
pertains. It also is an identifier for the set of properties that
the iCalendar object will consist 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
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permitted by the Calendaring and Scheduling Core Object
Specification.
The value for the "method" parameter is defined as follows:
method = 1*(ALPHA / DIGIT / "-")
; IANA registered iCalendar object method
Optional parameters: charset, 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.
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 the components are specified
as a comma-separated list of values.
The value for the "component" parameter is defined as follows:
component = "VEVENT" / "VTODO" / "VJOURNAL" / "VFREEBUSY"
/ x-name / iana-token
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 each property in the content entity MAY also have special
characters encoded 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, an "Attendee" of a "VEVENT", "VTODO",
"VJOURNAL" calendar component is the only person authorized to
update any parameter associated with their "ATTENDEE" property and
send it to the "Organizer". An 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
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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.
Intended Usage: COMMON
Published specification: This memo.
Author/Change controllers:
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 Considerations
The iCalendar object consists of lines of text. This section defines
how the content lines MUST be formatted.
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4.1.1 Content Lines
The iCalendar object consists of individual lines of text, delimited
by a line break, which is a CRLF sequence (ASCII decimal 13, followed
by ASCII decimal 10). Lines of text should not be longer than 76
characters, excluding the line break.
Long lines of text can 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 long 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.
An intentional formatted text line break MAY only be included in a
property value by representing the line break with the character
sequence of BACKSLASH (ASCII decimal 92), followed by a LATIN SMALL
LETTER N (ASCII decimal 110) or a LATIN CAPITAL LETTER N (ASCII
decimal 78), that is "\n" or "\N".
For example a multiple line "DESCRIPTION" property value of:
Project XYZ Final Review
Conference Room - 3B
Come Prepared.
Could be represented as:
DESCRIPTION:Project_XYZ Final_Review\n
Conference Room - 3B\nCome_Prepared.
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 as defined by the following notation:
contentline = name *(";" [WSP] param ) ":" [WSP] value-list CRLF
; Lines longer than 75 characters should be folded
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name = iana-token / x-name
x-name = "X-" 1*(ALPHA / DIGIT / "-")
;Reservered for experimental use.
param = param-name "=" param-value *("," param-value)
param-name = iana-token
param-value = quoted-string / text
value-list = value-struct *([FOLD] "," value-struct)
; permitted values are restricted by valuetype
value-struct = value-elem *([FOLD] ";" value-elem)
value-elem = folded-text / folded-b
; encoding determined by encoding parameter
iana-token = 1*(ALPHA / DIGIT / "-")
; iCalendar identifier registered with IANA
text = *SAFE-CHAR
quoted-string = DQUOTE *(QSAFE-CHAR / QUOTED-CHAR) DQUOTE
folded-text = *([FOLD] (SAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR))
folded-base64 = *([FOLD] 4B-CHAR) [[FOLD] b-end]
base64-end = (2B-CHAR "==") / (3B-CHAR "=")
ESCAPED-CHAR = "\" ("\" / DQUOTE / ";" / "," / "N" / "n")
; \\ encodes \, \" encodes ", \N or \n encodes newline
; \; encodes ;, \, encodes ,
B-CHAR = ALPHA / DIGIT / "+" / "/"
FOLD = CRLF WSP
; not considered part of the value
NON-ASCII = %x80-FF
; use restricted by charset parameter
; on outer MIME object
QSAFE-CHAR = %x20-21 / %x23-5B / %x5D-7E / NON-ASCII
; Any character except CTLs, DQUOTE, or "\"
QUOTED-CHAR = "\" ("\" / DQUOTE)
; \\ encodes \, \" encodes "
SAFE-CHAR = %x20-21 / %x23-2B / %x2D-39 / %x3C-5B
%x5D-7E / NON-ASCII
; Any character except CTLs, DQUOTE, ";", ":", "\", ","
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ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
BIT = "0" / "1"
CHAR = %x01-7F
; any 7-bit US-ASCII character, excluding NUL
CR = %x0D
; carriage return
CRLF = CR LF
; Internet standard newline
CTL = %x00-1F / %x7F
; controls
DIGIT = %x30-39
; 0-9DQUOTE = %x22
WSP = SPACE / HTAB
SPACE = %x20
HTAB = %x09
4.1.2 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).
A COLON character in a property value does not need to be escaped
with a BACKSLASH character.
A BACKSLASH character (ASCII decimal 92) in a property value MUST be
escaped with another BACKSLASH character. A COMMA character in a
property value MUST be escaped with a BACKSLASH character (ASCII
decimal 92). A SEMICOLON character in a property value MUST be
escaped with a BACKSLASH character (ASCII decimal 92).
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.
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ATTENDEE;RSVP=TRUE;ROLE=ATTENDEE:MAILTO:J.Smith
RDATE;VALUE=DATE:19970304,19970504,19970704,19970904
4.1.3 Multiple Values
Each property defined in the iCalendar object MAY have multiple
values, if allowed in the definition of the specific property. 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).
4.1.4 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
addition, 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=text:MIICajCCAdOgAwIBAgICBEUwDQYJKoZI
hvcNAQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENv
bW11bmljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZvcm1hdGlv
biBTeXN0 <...remainder of "B" encoded binary data...>
4.1.5 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.
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Property parameter values that contain the COLON, SEMICOLON, COMMA or
BACKSLASH character separators MUST be specified as quoted-string
text values. For example:
DESCRIPTION;ALTREP="http://www.wiz.org":The Fall'98 Wild Wizards
Conference - - Las Vegas, NV, USA
The general property parameters defined by this memo are specified
the following notation:
parameter = altrepparm ;Alternate text representation
/ encodingparm ;Inline encoding
/ languageparm ;Text language
/ valuetypeparm ;Property value data type
4.1.6 Alternate Text Representation
The "ALTREP" property parameter is an OPTIONAL property parameter. It
specifies the URI that points to an alternate representation for a
textual property value. The property MUST 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.
For example:
DESCRIPTION;ALTREP="CID:":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.
Content-Type:text/html
Content-Id:
Project XYZ Review Meeting will include the following
agenda items:
Market
OverviewFinancesProject Management
The "ALTREP" property parameter is defined by the following notation:
altrepparm = "altrep" "=" uri
4.1.7 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.
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4.1.8 Inline Encoding
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].
The "ENCODING" property parameter is defined by the following
notation:
encodingparam = "encoding" "=" "8bit" / "b" / iana-token
/ x-name
;"8bit" text encoding is defined in [RFC 2045]
;"b" binary encoding format is defined in [RFC 2047]
;Some other IANA registered iCalendar encoding type
;A non-standard, experimental encoding type
4.1.9 Language
The "LANGUAGE" property parameter is an OPTIONAL property parameter.
It identifies the language used in text values. 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.
The "LANGUAGE" property parameter is defined by the following
notation:
languageparm = "language" "=" language
language =
4.1.10 Value Data Types
The "VALUE" property parameter is an OPTIONAL property parameter. It
is used to identify the data type and format of the property value.
The values of a property MUST be of a single data type. For example,
a "RDATE" property cannot have a combination of DATE-TIME and TIME
values.
The "VALUE" property parameter is defined by the following notation:
valuetypeparm = "value" "=" valuetype
valuetype = "boolean"
/ "cal-address"
/ "date"
/ "date-time"
/ "duration"
/ "float"
/ "integer"
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/ "period"
/ "recur"
/ "text"
/ "time"
/ "uri"
/ "utc-offset"
/ x-name
;Some experimental iCalendar data type.
/ iana-token
;Some other IANA registered iCalendar data type.
The following data types are defined by this memo.
4.1.10.1 Boolean
The "BOOLEAN" data type is used to identify properties that contain
either a "true" or a "false" boolean value. These values are case
insensitive. The data type is defined by the following notation:
boolean = "TRUE" / "FALSE"
For example, any of the following are equivalent:
TRUE
true
TrUe
4.1.10.2 Calendar User Address
The "CAL-ADDRESS" data type is used to identify properties that
contain an address of a calendar user. 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]. The data
type is as defined by the following notation:
cal-address = uri
4.1.10.3 Date
The "DATE" data type is used to identify values that contain a
calendar date. The format is expressed as the [ISO 8601] complete
representation, basic format for a calendar date. The text 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. The data type is defined by the following
notation:
date-fullyear = 4DIGIT
date-month = 2DIGIT ;01-12
date-mday = 2DIGIT ;01-28, 01-29, 01-30, 01-31
;based on month/year
date = date-fullyear date-month date-mday
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For example, the following represents July 14, 1997:
19970714
4.1.10.4 Date-Time
The "DATE-TIME" data type is used to identify values that contain a
precise calendar date and time of day. The format is expressed as 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 defined below. The
data type is defined by the following notation:
date-time = date "T" time ;As specified above in date and time
The following represents July 14, 1997, at 1:30 PM in UTC and the
equivalent time in New York (four hours behind UTC in DST), expressed
as a local time and local time with UTC offset:
19970714T133000Z
19970714T083000
19970714T083000-0400
4.1.10.5 Duration
The "DURATION" data type is used to identify properties that contain
a duration of time. 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. The
data type is defined by the following notation:
dur-second = 1*DIGIT "S"
dur-minute = 1*DIGIT "M" [dur-second]
dur-hour = 1*DIGIT "H" [dur-minute]
dur-time = "T" (dur-hour / dur-minute / dur-second)
dur-week = 1*DIGIT "W"
dur-day = 1*DIGIT "D"
dur-month = 1*DIGIT "M" [dur-day]
dur-year = 1*DIGIT "Y" [dur-month]
dur-date = (dur-day / dur-month / dur-year) [dur-time]
duration = (["+"] / "-") "P" (dur-date / dur-time / dur-week)
For example, a duration of 10 years, 3 months, 15 days, 5 hours, 30
minutes and 20 seconds would be:
P10Y3M15DT5H30M20S
4.1.10.6 Float
The "FLOAT" data type is used to identify properties that contain a
real value number value. If the property permits, multiple "float"
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values MAY be specified using a COMMA character (ASCII decimal 44)
separator character. The data type is defined by the following
notation:
float = (["+"] / "-") 1*DIGIT ["." 1*DIGIT]
For example:
1000000.0000001
1.333
-3.14
4.1.10.7 Integer
The "INTEGER" data type is used to identify properties that contain a
signed integer value. 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. The data type is defined by the following notation:
integer = (["+"] / "-") *DIGIT
For example:
1234567890
-1234567890
+1234567890
432109876
4.1.10.8 Period of Time
The "PERIOD" data type is used to identify values that contain a
precise period of time. 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. For example, the period starting at 10 AM in Seattle
(eight hours behind UTC) on January 1, 1997 and ending at 11 PM in
Seattle on January 1, 1997 would be:
19970101T100000-0800/19970101T230000-0800
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. For example,
the period start at 10 AM in Seattle (eight hours behind UTC) on
January 1, 1997 and lasting 5 hours and 30 minutes would be:
19970101T100000-0800/PT5H30M
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The data type is defined by the following notation:
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.
period-start = date-time "/" duration
;ISO 8601 complete representation basic format for a period of time
;consisting of a start and duration of time.
period = period-explicit / period-start
4.1.10.9 Recurrence Rule
The "RECUR" data type is used to identify properties that contain a
recurrence rule specification. The data 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 60.
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Zero is the beginning of the minute and 60 is the beginning of the
next minute.
The BYMINUTE component specifies a COMMA character (ASCII decimal 44)
separated list of minutes within an hour. Valid values are 0 to 60.
Zero is the beginning of the hour and 60 is the beginning of the next
hour.
The BYHOUR component specifies a COMMA character (ASCII decimal 44)
separated list of hours of the day. Valid values are 0 to 24. Zero is
the start of the day and 24 is the start of the next day.
The BYDAY component specifies a COMMA character (ASCII decimal 44)
separated list of days of the week; MO, indicates Monday; TU,
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 postive (+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
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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
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 the list of "n"
unique values for each lower frequency BYxxx components is applied to
the list of "n" unique values for higher frequency BYxxx components.
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This process will not always increase the set of occurrences. If a
higher component is inconsistent with what was generated for lower
components, it would reduce the set. The ordering of BYxxx components
from lower frequency to higher frequency is as follows: BYMINUTE,
BYHOUR, BYDAY, BYMONTHDAY, BYYEARDAY, BYWEEKNO, BYMONTH, BYSETPOS.
Here is an example of evaluating multiple BYxxx components.
"FREQ=YEARLY;INTERVAL=2;BYMONTH=1;BYDAY=SU;BYHOUR=8,9;BYMINUTE=30"
would first apply the "BYMINUTE=30" To "BYHOUR=8,9" to arrive at
"every 8:30AM and 9:30AM". This in turn would be applied to
"BYDAY=SU" to arrive at "every Sunday at 8:30AM and 9:30AM". This
would be applied to "BYMONTH=1" to arrive at "every Sunday in January
at 8:30AM and 9:30AM". Considering the FREQUENCY and INTERVAL, this
would become "Every Sunday in January at 8:30AM and 9:30AM, every
other year". If the BYMINUTE, BYDAY, BYMONTHDAY, BYYEARDAY, BYHOUR or
BYMONTH component was missing, the appropriate mintues, hour, day or
month would have been retrieved from DTSTART.
The data type is defined by the following notation:
recur = "FREQ"=freq ";"
[("UNTIL" "=" enddate ";") / ("COUNT" "=" 1*DIGIT ";")]
["INTERVAL" "=" 1*DIGIT ";"]
["BYSECOND" "=" byseclist ";"]
["BYMINUTE" "=" byminlist ";"]
["BYHOUR" "=" byhrlist ";"]
["BYDAY" "=" bywdaylist ";"]
["BYMONTHDAY" "=" bymodaylist ";"]
["BYYEARDAY" "=" byyrdaylist ";"]
["BYWEEKNO" "=" bywknolist ";"]
["BYMONTH" "=" bymolist ";"]
["BYSETPOS" "=" bysplist ";"]
["WKST" "=" weekday ";")]
*("X-" word "=" word) ";"
;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 ;A UTC value
byseclist = seconds / ( seconds *("," seconds) )
seconds = 1DIGIT / 2DIGIT ;0 to 60
byminlist = minutes / ( minutes *("," minutes) )
minutes = 1DIGIT / 2DIGIT ;0 to 60
byhrlist = hour / ( hour *("," hour) )
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hour = 1DIGIT / 2DIGIT ;0 to 24
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) )
monthnum = 1DIGIT / 2DIGIT ;1 to 12
bysplist = setposday / ( setposday *("," setposday) )
setposday = yeardaynum
For 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.
4.1.10.10 Text
The "TEXT" data type is used to identify values that contain human
readable text. The character set and language in which the text is
represented is controlled by the "LANGUAGE" property parameters. The
data type is defined by the ABNF for "text" in section 4.1.1.
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4.1.10.11 Time
The "TIME" data type is used to identify values that contain a time
of day. The format is expressed as the [ISO 8601] complete
representation, basic format for a time of day. The text format
consists of a two-digit 24-hour of the day (i.e., values 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). If seconds of the minute are not
supported by an implementation, then a value of "00" should be
specified for the seconds component. Fractions of an hour, minute or
second are not supported by this format. This format is used to
represent local time, local time with UTC offset and UTC time. UTC
time is identified by a LATIN CAPITAL LETTER Z suffix character
(ASCII decimal 90), the UTC designator, appended to the time. The
local time with UTC offset is expressed as a local time, suffixed
with the signed offset from UTC. The UTC offset is express as the 2-
digit hours and 2-digit minutes difference from UTC. It is expressed
as positive, with a leading PLUS SIGN character (ASCII decimal 43),
if the local time is ahead of UTC. It is expressed as a negative,
with a leading HYPEN-MINUS character (ASCII decimal 45), if the local
time is behind UTC. Local time has neither the UTC designator nor the
UTC offset suffix text. The data type is defined by the following
notation:
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-numzone = ("+" / "-") time-hour time-minute
time-zone = "Z" / time-numzone
time = time-hour time-minute time-second [time-zone]
For example, the following represents 8:30 AM in New York, five hours
behind UTC, in local time and local time with UTC offset. In
addition, 1:30 PM in UTC is illustrated:
083000
083000-0500
133000Z
There are cases when a floating time is intended within a property
value. 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. 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 the recipient's locale and time zone. In most cases, a fixed
time is desired. To properly communicate a fixed time in a property
value, either UTC, local time with UTC offset, or local time with a
"VTIMEZONE" calendar component MUST be specified.
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4.1.10.12 URI
The "URI" data type is used to identify values that contain a uniform
resource identifier (URI) type of reference to the property value.
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.
The data type is defined by the following notation:
uri =
Any IANA registered URI format MAY be used. These include, but are
not limited to, those defined in RFC 1738 and RFC 2111.
For example, the following is a URI for a network file:
http://host1.com/my-report.txt
4.1.10.13 UTC Offset
The "UTC-OFFSET" data type is used to identify properties that
contain an offset from UTC to local time. The data type is defined by
the following notation:
utc-offset = time-numzone ;As defined above in time data type
The PLUS SIGN character MUST be specified for positive UTC offsets.
For 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
4.2 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]
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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:19970714T120000-0500
DTEND:19970714T235959-0500
SUMMARY:Bastille Day Party
END:VEVENT
END:VCALENDAR
4.3 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:19960415T083000-05:00
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".
4.4 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 with a
particular calendar semantic. For example, the calendar component MAY
specify a an event, a to-do, journal entry, time zone information, or
free/busy time information, or alarm.
The body of the iCalenar Object is defined by the following notation:
icalbody = calprops 1*component
calprops = [calscale] prodid method [source] [name] version
component = 1*(eventc / todoc / journalc / freebusyc /
/ timezonec)
4.4.1 Event Component
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
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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.
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]
[priority] [rstatus] [related] *resources *rdate
*rrule dtstamp [seq] [status] summary [transp] uid
[url] [recurid]
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.
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:19970903T083000-0800
DTEND:19970903T110000-0800
SUMMARY:Annual Employee Review
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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:19970401T083000-0800
DTEND:19970401T170000-0800
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
4.4.2 To-do Component
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".
A "VTODO" calendar component is defined by the following notation:
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] [percent] priority [rstatus]
[related] *resources *rdate *rrule [recurid] [seq]
[status] summary uid [url]
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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.
The following is an example of a "VTODO" calendar component:
BEGIN:VTODO
UID:19970901T130000Z-123404@host.com
DTSTAMP:19970901T1300Z
DTSTART:19970415T083000-0500
DUE:19970415T235959-0500
SUMMARY:1996 Income Tax Preparation
CLASS:CONFIDENTIAL
CATEGORIES:FAMILY,FINANCE
PRIORITY:1
STATUS:NEEDS-ACTION
END:VEVENT
4.4.3 Journal Component
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 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.
A "VJOURNAL" calendar component is defined by the following notation:
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] [related] *rdate *rrule
[rstatus] [seq] summary uid [url] [recurid]
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.
The following is an example of the "VJOURNAL" calendar component:
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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
4.4.4 Free/Busy Component
A "VFREEBUSY" calendar component is a grouping of component
properties that represents either a request for, or a reply with,
free or busy time information. Typically, this component exists in an
iCalendar object that is being used to either request or return free
or busy time information.
A "VFREEBUSY" calendar component is defined by the following
notation:
freebusyc = "BEGIN" ":" [WSP] "VFREEBUSY" CRLF
fbprop
"END" ":" [WSP] "VFREEBUSY" CRLF
fbprop = fbrequest / fbreply
fbrequest = 1*attendee dtstart dtend [duration] *comment dtstamp
[last-mod] *related [seq] uid
;This set of properties is used for free/busy time request.
fbreply = 1*attendee [created] *comment [dtstart dtend] dtstamp
*freebusy [last-mod] [related] [rstatus] [seq] uid
[url]
;This set of properties is used for free/busy time reply.
The "VFREEBUSY" calendar component cannot be nested within another
calendar component. The "VFREEBUSY" calendar components MAY be
related to each other with the "RELATED-TO" property. Multiple
"VFREEBUSY" calendar components MAY be specified within a iCalendar
object. This permits the grouping of Free/Busy information into
logical collections, such as monthly groups of busy time information.
The "VFREEBUSY" calendar component is intended for use in iCalendar
object methods involving requests for free time, requests for busy
time, requests for both free and busy, and the associated replies.
Free/Busy information can be expressed using the "FREEBBUSY"
property. This property provides a terse representation of time
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periods. One or more "FREEBUSY" properties MAY be specified in the
"VFREEBUSY" calendar component to describe the Free/Busy information.
Optionally, the "DTSTART" and "DTEND" properties MAY be specified to
express the start and end date and time for all of the Free/Busy
information in the "VFREEBUSY" calendar component. When present in a
"VFREEBUSY" calendar component, they 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.
The following is an example of a "VFREEBUSY" calendar component used
to request free or busy time information:
BEGIN:VFREEBUSY
ATTENDEE;ROLE=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
4.4.5 Alarm Component
A "VALARM" calendar component is a grouping of component properties
that is a reminder or alarm for an event or a to-do. The "VALARM"
calendar component MAY only be specified in a "VEVENT" or "VTODO"
calendar component. For example, it MAY define a reminder for a
pending event or an overdue to-do.
The "DTSTART" property specifies the calendar date and time of day
that the alarm will be triggered. The value MAY alternately be set to
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a DURATION, before or after the event or to-do, that the alarm will
be triggered.
A "VALARM" calendar component is defined by the following notation:
alarmc = "BEGIN" ":" [WSP] "VALARM" CRLF
alarmprop
"END" ":" [WSP] "VALARM" CRLF
alarmprop = *attendee *attach 1*categories *comment [description]
dtstart duration *related repeat [summary]
The "VALARM" calendar component can only appear within either a
"VEVENT" or "VTODO" calendar component. The "VALARM" calendar
components cannot be nested.
The "CATEGORIES" property within the "VALARM" calendar component
specifies the type or combination of types of the alarm. The
"CATEGORIES" 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.
In an AUDIO category of alarm, the first "ATTACH" property in the
"VALARM" calendar component that specifies an audio sound file is
intended to be rendered as the alarm effect. If an "ATTACH" property
is specified that does not refer to an audio sound file, then it is
not used by this category of alarm. In addition, any "ATTENDEE",
"DESCRIPTION" or "SUMMARY" properties are not used by this category
of alarm.
In a DISPLAY category of alarm, the "SUMMARY" property in the
"VALARM" calendar component is intended to be displayed as the alarm
effect. Any "ATTACH", "ATTENDEE" or "DESCRIPTION" properties in the
"VALARM" calendar component are not used by this category of alarm.
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 not used by this category of alarm.
In a PROCEDURE category of alarm, the first "ATTACH" property in the
"VALARM" calendar component that specifies a procedure or program is
intended to be invoked as the alarm effect. Any "ATTACH" properties
that do not refer to a procedure or program, then it is not used by
this category of alarm. In addition, the "ATTENDEE", "DESCRIPTION"
and "SUMMARY" properties are not used by this category of alarm.
"Calendar User Agents" that receive an iCalendar object with this
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category of alarm, should allow the "Calendar User" to disable or
otherwise ignore this category of alarm. While a very useful alarm
capability, the PROCEDURE category of alarm should be treated by the
"Calendar User Agent" as a potential security risk.
The following is an example of the "VALARM" calendar component:
BEGIN:VALARM
DTSTART:19970317T133000Z
REPEAT:4
DURATION:PT15M
CATEGORIES:DISPLAY,AUDIO
ATTACH:ftp://host.com/pub/sounds/bell-01.wav
SUMMARY:Breakfast meeting with executive team at 8:30 AM
END:VALARM
4.4.6 Timezone Component
The "VTIMEZONE" calendar component is used to define a time zone.
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.
Effective Transition Rule
Date (Date/Time) Offset Abbreviation
1920-1920 last Sun in Mar, 02:00 _0400 EDT
1920-1920 last Sun in Oct, 02:00 _0500 EST
1921-1966 last Sun in Apr, 02:00 _0400 EDT
1921-1954 last Sun in Sep, 02:00 _0500 EST
1955-1966 last Sun in Oct, 02:00 _0500 EST
1967-* last Sun 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
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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.
The "VTIMEZONE" calendar component is a grouping of component
properties that define a time zone description. The time zone
description specifies the effective Standard Time or Daylight Savings
Time rules for a particular time zone. The "VTIMEZONE" calendar
component cannot be nested within other calendar components. The
"VTIMEZONE" calendar component MAY be specified multiple times. If
the "VTIMEZONE" calendar component is missing, the recipient should
assume all local times are relative to the recipient's time zone. The
"VTIMEZONE" calendar component should be specified in the iCalendar
object before any other calendar components.
A "VTIMEZONE" calendar component is defined by the following
notation:
timezonec = "BEGIN" ":" [WSP] "VTIMEZONE" CRLF
tzprop
"END" ":" [WSP] "VTIMEZONE" CRLF
tzprop = *comment [daylight] dtstart [rdate / rrule]
[tzname] tzoffset
The "VTIMEZONE" calendar component is important for correct
interpretation of individual as well as recurring calendar components
that span a time zone transition. For example, from EST to EDT. The
exception to this are calendar components that are considered
floating (i.e., occurs at a particular local time no matter what time
zone you are in). If the iCalendar object contains a non-floating
calendar component that has a recurring date pattern (i.e., includes
the "RRULE" property) or a list of date and local time values (i.e.,
includes the "RDATE" property), one or more "VTIMEZONE" calendar
components MUST be specified, such that for the given range of the
recurrence (i.e., the earliest instance to latest instance), there is
valid time zone information for all instances. In other words, if all
of the instances of the pattern is entirely within one offset
observance, (e.g., all are in Standard Time), only one "VTIMEZONE"
calendar component need be present. If a time zone transition is
crossed, then other "VTIMEZONE" calendar components are needed.
Further, if there are known changes to the rules for the time zone,
even more "VTIMEZONE" calendar components are needed.
Each "VTIMEZONE" calendar component consists of several properties:
The "DAYLIGHT" property is a BOOLEAN value indicating Standard Time
(FALSE) or Daylight Savings Time (TRUE). The default for DAYLIGHT is
FALSE or Standard Time.
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The "DTSTART" property in this usage is a fully specified DATE-TIME
value, including the UTC offset, indicating the effective start date
and time for the time zone information. For example, 19671029T020000-
0400 represents the time at which the transition to Standard Time
took effect in 1967 for the eastern United States.
The "TZOFFSET" property is a UTC-OFFSET value indicating the UTC
offset for the time zone (Standard Time or Daylight Savings Time).
The "TZNAME" property is the customary name for the time zone.
The "RRULE" property indicates the recurrence rule for the transition
to this time zone. For example, in the United States, the transition
from Standard Time to Daylight Saving Time occurs on the first Sunday
in April at 02:00. If a recurrence rule describing the transition is
known to have an effective end date, the UNTIL recurrence rule
parameter is used to specify that end date and time. If the
recurrence rule for a particular observance (Daylight Saving Time) is
changing, then the UNTIL of the first rule will be equal to the last
valid instance (the last date-time) of this particular rule. See
example below.
Alternatively, the "RDATE" property can be used. The "RDATE" property
is a property that indicates the individual dates and/or times that
the transition takes effect. The values supplied for "RDATE" property
for each "VTIMEZONE" calendar component MUST provide valid time zone
information of all instances of the recurrence specified for the
calendar component to which this time zone information is to be
applied.
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 1997,
April 6, at 02:00:00 EST (i.e., the earliest effective transition
date and time) and ends no later than 1998, April 7, 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 ocurrs every
Friday, 8am-9am, starting June 1, 1997, ending Dec 31, 1997.
BEGIN:VTIMEZONE
DAYLIGHT:FALSE
RDATE:19971026T020000-0400
TZOFFSET:-0500
TZNAME:EST
END:VTIMEZONE
BEGIN:VTIMEZONE
DAYLIGHT:TRUE
RDATE:19970406T020000-0500
TZOFFSET:-0400
TZNAME:EDT
END:VTIMEZONE
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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
recurrening event starting today and continuing on into the known
future.
BEGIN:VTIMEZONE
DAYLIGHT:FALSE
DTSTART:19671029T020000-0400
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSET:-0500
TZNAME:EST
END:VTIMEZONE
BEGIN:VTIMEZONE
DAYLIGHT:TRUE
DTSTART:19870405T020000-0500
RRULE: FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
TZOFFSET:-0400
TZNAME:EDT
END:VTIMEZONE
This is an example showing a ficticious 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
DAYLIGHT:FALSE
DTSTART:19671029T020000-0400
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSET:-0500
TZNAME:EST
END:VTIMEZONE
BEGIN:VTIMEZONE
DAYLIGHT:TRUE
DTSTART:19870405T020000-0500
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T020000-0500
TZOFFSET:-0400
TZNAME:EDT
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
DAYLIGHT:FALSE
DTSTART:19671029T020000-0400
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSET:-0500
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TZNAME:EST
END:VTIMEZONE
BEGIN:VTIMEZONE
DAYLIGHT:TRUE
DTSTART:19870405T020000-0500
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T020000-0500
TZOFFSET:-0400
TZNAME:EDT
END:VTIMEZONE
BEGIN:VTIMEZONE
DAYLIGHT:TRUE
DTSTART:19990327T020000-0500
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
TZOFFSET:-0400
TZNAME:EDT
END:VTIMEZONE
4.5 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.
4.5.1 Calendar Scale
This property is identified by the property name CALSCALE. This
property defines the calendar scale used for the calendar information
specified in the iCalendar object. 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.
The property is defined by the following notation:
calscale = "CALSCALE" ":" [WSP] calvalue CRLF
calvalue = "GREGORIAN" / iana-token
The following is an example of this property:
CALSCALE:GREGORIAN
The data type for this property is TEXT.
4.5.2 Method
This property is identified by the property name METHOD. This
property defines the iCalendar object method associated with the
calendar object. When used in a MIME message entity, the value of
this property MUST be the same as the Content-Type "method" parameter
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value. This property can only appear once within the iCalendar
object.
The property is defined by the following notation:
method = "METHOD" ":" [WSP] profvalue CRLF
profvalue =
The following is an example of this property when the iCalendar
object is used to request a meeting:
METHOD: REQUEST
The data type for this property is TEXT.
4.5.3 Product Identifier
This property is identified by the property name PRODID. This
property specifies the identifier for the product that created the
iCalendar object. 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 calendar property MUST be specified in the
iCalendar object but can only appear once.
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.
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.
The following is an example of this property:
PRODID:-//ABC Corporation//NONSGML My Product//EN
The data type for this property is TEXT.
4.5.4 Source
This property is identified by the property name SOURCE. This
property is defined by the [MIME DIR] memo. In this memo, the
property identifies the URI for the source of the iCalendar object.
The URI is useful for accessing the iCalendar object using a calendar
access protocol.
The property is defined by the following notation:
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source = "SOURCE" ":" [WSP] uri CRLF
The following are examples of this property:
SOURCE:http://xyz.corp.com/corp-cals/1997-events.or4
SOURCE:http://xyz.corp.com/calendars/~jdoe
The data type for this property is URI.
4.5.5 Source Name
This property is identified by the property name NAME. This property
is defined by the [MIME DIR] memo. The property identifies the
displayable, presentation name for the source of the iCalendar
object. The source name is a useful text to associate in the user-
interface of an application with the value in the SOURCE property.
The property is defined by the following notation:
name = "NAME" ":" [WSP] text CRLF
The following is an example of this property:
NAME:1997 Events Calendar for XYZ Corporation
The data type for this property is TEXT.
4.5.6 Version
This property is identified by the property name VERSION. This
property specifies the identifier corresponding to the highest
version number or the minimum and maximum range of the MIME
Calendaring and Scheduling Content Type specification supported by
the implementation that created the iCalendar object. A value of
"2.0" corresponds to this memo. This calendar property MUST appear
within the iCalendar object but can only appear once.
The property is defined by the following notation:
version = "VERSION" ":" [WSP] vervalue CRLF
vervalue = "2.0" ;This memo
/ maxver
/ (minver ";" [WSP] maxver)
minver =
;Minimum iCalendar version used to create the iCalendar object
maxver =
;Maximum iCalendar version used to create the iCalendar object
The following is an example of this property:
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VERSION:2.0
The data type for this property is TEXT.
4.6 Component Properties
The following properties MAY appear within calendar components, as
specified by each component property definition.
4.6.1 Attachment
This property is identified by the property name ATTACH. The property
provides the capability to associate an external object with a
calendar component. For example, a document to be reviewed at a
scheduled event or the description of the process steps for a to-do.
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.
The property is defined by the following notation:
attach = ("ATTACH" ":" [WSP] uri CRLF) /
("ATTACH" ";" [WSP] "ENCODING" "=" "b" ";" [WSP]
"VALUE" "=" "text" ":" [WSP] folded-b
The following are examples of this property:
ATTACH:CID:jsmith.part3.960817T083000.xyzMail@host1.com
ATTACH:FTP://xyzCorp.com/pub/reports/r-960812.ps
The default data type for this property is URI. The data type MAY
also be reset to TEXT in order to include inline binary encoded
content information.
4.6.2 Attendee
This property is identified by the property name ATTENDEE. The
property defines an attendee within a calendar component. The
property MAY only be specified within the "VEVENT", "VTODO",
"VJOURNAL", "VFREEBUSY" and "VALARM" calendar components.
The property has the property parameters TYPE, for the type of
attendee, ROLE, for the intended role of the attendee; STATUS, 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 people that the original request was
delegated to; and DELEGATED-FROM, to indicated whom the request was
delegated from.
A recipient delegated a request MUST inherit the RSVP and EXPECT
values from the attendee that delegated the request to them.
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Multiple attendees MAY be specified by including multiple "ATTENDEE"
properties within the MIME calendaring entity.
The property data type default is CAL-ADDRESS. The property data type
MAY also be set to URI. This provides a useful mechanism to allow
more than just the address of the attendee to be referenced. If the
value is a URI, then it MUST be able to be resolved to a calendar
address.
The property is defined by the following notation:
attendee = "ATTENDEE" *(";" [WSP] parameter)
*(";" [WSP] attparam) ":" [WSP]
(cal-address / uri) CRLF
;Value MUST match default or explicit data type
attparam = typeparm / roleparm / statusparm / rsvpparm
/ expectparm / memberparm / deletoparm / delefromparm
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
roleparm = "ROLE" "="
("ATTENDEE" ; Indicates a regular attendee
/ "OWNER" ; Indicates owner of event or to-do
/ "ORGANIZER" ; Indicates organizer of event or to-do
/ "DELEGATE") ; Indicates delegate to event or to-do
;Default is ATTENDEE
statusparm = "STATUS" "="
("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.
/ "DELEGATED" ; Indicates event or to-do delegated
; to another ATTENDEE
/ "CANCELLED") ; Indicates event or to-do cancelled for
; ATTENDEE
;Default is NEEDS-ACTION
rsvpparm = "RSVP" "="
("TRUE" ; Indicates response requested
/ "FALSE") ; Indicates no response needed
;Default is FALSE
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expectparm = "EXPECT" "="
("FYI" ; Indicates request is for your info
/ "REQUIRE" ; Indicates presence is required
/ "REQUEST") ; Indicates presence is requested
;Default is FYI
memberparm = "MEMBER" "=" cal-address *("," [WSP] cal-address)
; Indicates a group or mailing list
deletoparm = "DELEGATED-TO" "=" cal-address *("," [WSP]
cal-address)
; Indicates who the request is delegated to
delefromparm = "DELEGATED-FROM" "=" cal-address *("," [WSP]
cal-address)
;Indicates who the request is delegated from
The following are examples of this property's use for a to-do:
ATTENDEE;ROLE=OWNER;STATUS=COMPLETED: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:
ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED: MAILTO:John Smith
ATTENDEE;ROLE=ATTENDEE;STATUS=TENTATIVE:MAILTO:Henry Cabot
ATTENDEE;ROLE=DELEGATE;STATUS=ACCEPTED:MAILTOJane Doe
The following is an example of this property with the value specified
as an URI reference to a vCard that contains the information about
the attendee:
ATTENDEE;ROLE=ATTENDEE;STATUS=ACCEPTED;VALUE=URI:
http://www.xyz.com/~myvcard.vcf
The following is an example of this property with "delegatee" and
"delegator" information for an event:
ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:MAILTO:John Smith
ATTENDEE;ROLE=DELEGATE;STATUS=TENTATIVE;DELEGATED-FROM=
"MAILTO:iamboss@host2.com":MAILTO:Henry Cabot
ATTENDEE;ROLE=ATTENDEE;STATUS=DELEGATED;DELEGATED-TO=
"MAILTO:hcabot@host2.com:MAILTO:iamboss(The Big Cheese)@host2.com
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ATTENDEE;ROLE=DELEGATE;STATUS=ACCEPTED:MAILTO:Jane Doe
The default data type for this property is CAL-ADDRESS. The data type
MAY be reset to URI; in which case the value is a location or message
that contains the information that is to be used to specify the
attendee address.
4.6.3 Categories
This property is identified by the property name CATEGORIES. This
property defines the categories for a calendar component. The
property MAY be specified within the "VEVENT", "VTODO" or "VJOURNAL"
calendar component with an arbitrary text value. In the "VALARM"
calendar component the property MUST be specified to declare the
alarm category. More than one category MAY be specified as a list of
categories separated by the COMMA character (ASCII decimal 44).
The properties is defined by the following notation:
categories = "CATEGORIES" *(";" [WSP] parameter) ":" [WSP]
catvalue CRLF
catvalue = cat1value *["," [WSP] cat1value]
/ cat2value *["," [WSP] cat2value]
cat1value = "ANNIVERSARY" / "APPOINTMENT" / "BUSINESS"
/ "EDUCATION" / "HOLIDAY" / "MEETING" / "MISCELLANEOUS"
/ "NON-WORKING HOURS" / "NOT IN OFFICE" / "PERSONAL"
/ "PHONE CALL" / "SICK DAY" / "SPECIAL OCCASION"
/ "TRAVEL" / "VACATION" / word
;Used only in "VEVENT", "VTODO" and "VJOURNAL" calendar components.
cat2value = "AUDIO" / "DISPLAY" / "EMAIL" / "PROCEDURE"
/ iana-token / x-name
;Used only in "VALARM" calendar component.
The following are examples of this property in a "VEVENT", "VTODO" or
"VJOURNAL" calendar component:
CATEGORIES:APPOINTMENT,EDUCATION
CATEGORIES:MEETING
The following are examples of this property in a "VALARM" calendar
component:
CATEGORIES:AUDIO,DISPLAY
CATEGORIES:PROCEDURE
The data type for this property is TEXT.
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4.6.4 Classification
This property is identified by the property name CLASS. This property
defines the access classification for a calendar component. The
property MAY only be specified in a "VEVENT", "VTODO" or "VJOURNAL"
calendar component. The property MAY only be specified once.
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.
The property is defined by the following notation:
class = "CLASS" ":" [WSP] classvalue CRLF
classvalue = "PUBLIC" / "PRIVATE" / "CONFIDENTIAL" / iana-token
/ x-name
;Default is PUBLIC
The following is an example of this property:
CLASS:PUBLIC
The data type for this property is TEXT.
4.6.5 Comment
This property is identified by the property name COMMENT. This
property specifies non-processing information intended to provide a
comment to the calendar user. The property MAY be specified in any of
the calendar components. The property MAY be specified multiple
times.
The property is defined by the following notation:
comment = "COMMENT" ":" [WSP] text CRLF
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
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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.
4.6.6 Contact
This property is defined by the property name CONTACT. The property
is used to represent contact information or alternately a reference
to contact information associated with the calendar component. The
property MAY only be specified in the "VEVENT", "VTODO" and
"VJOURNAL" calendar components. The property value consists of
textual contact information. Alternately, the value type for the
property can be reset such that the property references the URI to
the contact information.
The property is defined by the following notation:
contact = "CONTACT" *(";" [WSP] parameter) ":" [WSP]
text / uri CRLF
The following is an example of this property referencing textual
contact information:
CONTACT:Jim Dolittle\, ABC Industries\, +1-919-555-1234
The following is an example of this property referencing a LDAP URI
to a directory entry containing the contact information:
CONTACT;VALUE=URI:ldap://host.com:6666/o=3DABC%20Industries\,
c=3DUS??(cn=3DBJim%20Dolittle)
The following is an example of this property referencing a MIME body
part containing the contact information, such as a vCard embedded in
a [MIME-DIR] content-type:
CONTACT;VALUE=URI:
The default data type for this property is TEXT. The data type MAY be
reset to URI in order to specify a reference to the contact
information.
4.6.7 Date/Time Completed
This property is identified by the property name COMPLETED. This
property defines the date and time that a to-do was actually
completed. The property MAY be specified once in a "VTODO" component.
The date and time is an UTC value.
The property is defined by the following notation:
completed = "COMPLETED" ":" [WSP] date-time CRLF
The following is an example of this property:
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COMPLETED:19960401T235959Z
The data type for this property is DATE-TIME.
4.6.8 Date/Time Created
This property is identified by the property name CREATED. This
property specifies the date and time that the calendar information
was created by the Organizer. The property MAY be specified in any of
the calendar components. The property MAY only be specified once. The
date and time is an UTC value.
The property is defined by the following notation:
created = "CREATED" ":" [WSP] date-time CRLF
The following is an example of this property:
CREATED:19960329T133000Z
The data type for this property is DATE-TIME.
4.6.9 Date/Time Due
This property is identified by the property name DUE. This property
defines the date and time that a to-do is expected to be completed.
The time can either be in local time, local time with UTC offset or
UTC time. The property MAY only be specified in a "VTODO" calendar
component and only once. The value MUST be a date/time after the
DTSTART value, if specified.
The property is defined by the following notation:
due = "DUE" ":" [WSP] date-time CRLF
The following is an example of this property:
DUE:19960401T235959Z
The type for this property is DATE-TIME.
4.6.10 Date/Time End
This property is identified by the property name DTEND. This property
MAY be specified within the "VEVENT", "VFREEBUSY", and "VTIMEZONE"
calendar components.
Within the "VEVENT" calendar component, this property defines the end
date and time for the event. The property is REQUIRED in "VEVENT"
calendar components. The time can either be in local time, local time
with UTC offset or UTC time. The local time is only to be used to
specify date and time values that do not need to be fixed. A
recipient MUST assume their own time zone for data and time values
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that do not include time zone information. 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 in local time with UTC offset or UTC time. The
value MUST be later in time than the value of the "DTSTART" property.
The property is defined by the following notation:
dtend = "DTEND" ":" [WSP] date-time CRLF
The following is an example of this property:
DTEND:19960401T235959Z
The data type for this property is DATE-TIME.
4.6.11 Date/Time Stamp
This property is identified by the property name DTSTAMP. This
property specifies an UTC date/time stamp. The property indicates the
date/time that the iCalendar object instance was created. This
property MUST be included in "VEVENT", "VTODO", "VJOURNAL" and
"VFREEBUSY" calendar components to permit the recipient to know when
the iCalendar object was created.
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.
The property is defined by the following notation:
dtstamp = "DTSTAMP" ":" [WSP] date-time CRLF
The value type for this property is DATE-TIME. The value MUST be a
UTC date/time value.
4.6.12 Date/Time Start
This property is identified by the property name DTSTART. This
property MAY be specified within the "VEVENT", "VTODO", "VFREEBUSY",
and "VTIMEZONE" calendar components.
Within the "VEVENT" calendar component, this property defines the
start date and time for the event. The property is REQUIRED in
"VEVENT" calendar components. The time can either be in local time,
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local time with UTC offset or UTC time. The local time is only to be
used to specify date and time values that do not need to be fixed. A
recipient MUST assume their own time zone for data and time values
that do not include time zone information. 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 local time with UTC offset or 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 as a UTC time.
The property is defined by the following notation:
dtstart = "DTSTART" *(";" [WSP] parameter) ":" [WSP] (date-time
/ date) CRLF
The following is an example of this property:
DTSTART:19960401T235959-0600
The default data type for this property is DATE-TIME. The data type
MAY be overridden to be DATE.
4.6.13 Daylight
This property is identified by the property name DAYLIGHT. This
property MAY only be specified in a "VTIMEZONE" calendar component.
This property specifies whether Daylight Saving Time (i.e., value is
TRUE) or Standard Time (i.e., value is FALSE) is in effect for the
time zone. The default value is FALSE or Standard Time.
The property is defined by the following notation:
daylight = "DAYLIGHT" ":" [WSP] boolean CRLF
;Default value is FALSE
The following is an example of this property:
DAYLIGHT:TRUE ;Specifies DST in effect in time zone
The data type for this property is BOOLEAN.
4.6.14 Description
This property is identified by the property name DESCRIPTION. This
property provides a more complete description of the calendar
component, than that provided by the "SUMMARY" property. The property
MAY be specified in the "VEVENT", "VTODO" and "VJOURNAL" calendar
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components. The property MAY be specified multiple times only within
a "VJOURNAL" calendar component.
The property is defined by the following notation:
description = "DESCRIPTION" *(";" [WSP] parameter) ":" [WSP]
text CRLF
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.
The data type for this property is TEXT.
4.6.15 Duration
This property is identified by the property name DURATION. The
property specifies a duration of time. The property MAY be specified
in a "VEVENT" calendar component in order to specify a duration of
the event, instead of an explicit end date/time. The property MAY be
specified in a "VTODO" calendar component in order to specify a
duration for the to-do. The property MAY be specified in a
"VFREEBUSY" calendar component in order to specify the amount of free
time being requested. The property MAY be specified in an "VALARM"
calendar component in order to specify the period between repeating
alarms.
The property is defined by the following notation:
duration = "DURATION" ":" [WSP] duration CRLF
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
The data type for this property is DURATION.
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4.6.16 Exception Date/Times
This property is identified by the property name EXDATE. This
property defines the list of date/time exceptions for a recurring
"VEVENT", "VTODO" or "VJOURNAL" calendar component. The times can
either be in local time, local time with UTC offset or UTC time.
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 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".
The property is defined by the following notation:
exdate = "EXDATE" *(";" [WSP] parameter) ":" [WSP] [date-time /
date] *("," [WSP] date-time/date) CRLF
;Values MUST match the specified value type.
The following is an example of this property:
EXDATE:19960402T010000Z,19960403T010000Z,19960404T010000Z
The data type for this property is DATE-TIME. The data type MAY be
reset to DATE.
4.6.17 Exception Rule
This property is identified by the property name EXRULE. This
property defines a rule or repeating pattern for an exception to a
recurrence set. This property MAY only be specified in the "VEVENT",
"VTODO" or "VJOURNAL" calendar components.
The exception rule, if specified, is used in computing the recurrence
set. The recurrence set is the complete set of recurrence instances
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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".
The property is defined by the following notation:
exrule = "EXRULE" ":" [WSP] recur CRLF
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.
4.6.18 Free/Busy Time
This property is identified by the property name FREEBUSY. The
property defines one or more free or busy time intervals. 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 is either local time with UTC offset or a UTC
value.
The "FREEBUSY" property MAY include the "TYPE" property parameter to
specify whether the information defines a free or busy time interval.
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The default "TYPE" property parameter value is BUSY. The property MAY
also include the "STATUS" 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 - - or busy time that has been tentatively
scheduled. The default "STATUS" property parameter value is BUSY. The
property is defined by the following notation:
freebusy = "FREEBUSY" *(";" [WSP] parameter) [";" [WSP]
fbparmlist] ":" [WSP] fbvalue CRLF
fbparmlist = fbparam *(";" [WSP] fbparam)
fbparam = fbtype / fbstatus
fbtype = "TYPE" "=" ("FREE" or "BUSY")
;Default is BUSY
fbstatus = "STATUS" "="
"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 tentatively
;scheduled interval.
;Default is BUSY
fbvalue = period *["," [WSP] period]
;Value MUST match default or explicit data type
The following are some examples of this property:
FREEBUSY;STATUS=UNAVAILABLE:19970308T160000Z/PT8H30M
FREEBUSY;TYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H
"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 "STATUS" property parameter
type (e.g., all values of a particular "STATUS" listed together in a
single property).
The data type for this property is PERIOD.
4.6.19 Geographic Position
This property is identified by the property name GEO. This property
specifies information related to the global position for a "VEVENT"
or "VTODO" calendar component. The property value specifies latitude
and longitude, in that order (i.e., "LAT LON" ordering). The
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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.
The property is defined by the following notation:
geo = "GEO" ":" [WSP] geovalue CRLF
geovalue = float ";" [WSP] float
;Latitude and Longitude components
The following is an example of this property:
GEO:37.386013;-122.082932
The default data type for this property is FLOAT.
4.6.20 Last Modified
This property is identified by the property name LAST-MODIFIED. The
property specifies the date and time that the calendar information
was last revised. This property MAY be specified in the "VEVENT",
"VTODO", "VJOURNAL" or "VFREEBUSY" calendar components. The data and
time MUST be a UTC value.
The property is defined by the following notation:
last-mod = "LAST-MODIFIED" ":" [WSP] date-time CRLF
The following is are examples of this property:
LAST-MODIFIED:19960817T133000Z
The data type for this property is DATE-TIME.
4.6.21 Location
This property is identified by the property name LOCATION. The
property defines the intended location for the "VEVENT" or "VTODO"
calendar component. The property MAY only be specified within a
"VEVENT" or "VTODO" calendar component.
The property is defined by the following notation:
location = "LOCATION *(";" [WSP] parameter) ":" [WSP] locavalue
CRLF
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locavalue = text / uri ;The value MUST be the same type as the
;default or explicit data type.
The following are some examples of this property:
LOCATION:Conference Room - F123, Bldg. 002
LOCATION;VALUE=URI:http://www.xyzcorp.com/~jsmith.vcf
The default data type for this property is TEXT. The data type MAY be
reset to URI. In the case of the data type being URI, the property
value MAY reference a vCard object. This provides a useful mechanism
to specify a location in terms of its electronic business card.
4.6.22 Percent Complete
This property is identified by the property name PERCENT-COMPLETE.
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. The
property MAY only be specified once and within a "VTODO" calendar
component. The property value is an 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.
The property is defined by the following notation:
percent = "PERCENT-COMPLETE" ":" [WSP] integer CRLF
The following is an example of this property to show 39% completion:
PERCENT-COMPLETE:39
The data type for this property is INTEGER.
4.6.23 Priority
This property is identified by the property name PRIORITY. The
property defines the priority for event or to-do. The property MAY
only be specified within a "VEVENT" or "VTODO" calendar component.
The value is an integer. 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.
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The property is specified by the following notation:
priority = "PRIORITY" ":" [WSP] integer CRLF
;Default is zero
The following is an example of this property:
PRIORITY:2
The data type for this property is INTEGER.
4.6.24 Recurrence Date/Times
This property is identified by the property name RDATE. This property
defines the list of date/times for a recurrence set. The property MAY
only appear within the "VEVENT", "VTODO", "VJOURNAL" or "VTIMEZONE"
calendar components. 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 times can either be in local time, local time with UTC
offset or UTC based time. If local time is used, the "VTIMEZONE"
calendar component MUST be included in the iCalendar object,
otherwise the local time value will be interpreted relative to the
time zone of the recipient. The period values for "RDATE" property
are specified using a specific start and a specific end basic format
(period-explicit) or the period with a specific start and a specific
duration basic format (period-start).
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.
The property is defined by the following notation:
rdate = "RDATE" *(";" [WSP] parameter) ":" [WSP] rdvalue
*("," [WSP] rdvalue) CRLF
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rdvalue = date-time / date / period
;Value MUST match the specified data type
The following are examples of this property:
RDATE:19970714T083000-0400
RDATE;VALUE=PERIOD:19960403T020000Z/19960403T040000Z,
19960404T010000Z/PT3H
RDATE;VALUE=DATE:19970101,19970120,19970217,19970421
19970526,19970704,19970901,19971014,19971128,19971129,19971225
The default data type for this property is DATE-TIME. The data type
MAY be reset to DATE or PERIOD.
4.6.25 Recurrence ID
This property is identified by the property name RECURRENCE-ID. This
property is used in conjunction with the "UID" 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.
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.
The time of day component for the value MUST be either an UTC or a
local time with UTC offset time format, unless the original calendar
object was expressed as a "floating" calendar object; that is in
local time with no time zone calendar component specified. If the
value of the "DTSTART" property is a DATE type value, then the value
MUST be the calendar date for the recurrence instance.
The date/time value is set to the time when the original recurrence
instance would occur - - meaning that if the intent is to change a
Friday meeting to Thursday, the date/time is still set to the
original Friday meeting.
The "RECURRENCE-ID" property is used in conjunction with the "UID"
property to identify a particular instance of a recurring event, to-
do or journal.
The property is defined by the following notation:
recurid = "RECURRENCE-ID" *(";" [WSP] parameter)
[";" [WSP] rangeparm] ":" [WSP] [date-time / date]
;Value must match value type.
rangeparm = "RANGE" "=" ("THISANDPRIOR" / "THISANDFUTURE")
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The default value for the range parameter is the single recurrence
instance only.
The following are examples of this property:
RECURRENCE-ID:19960401T235959Z
RECURRENCE-ID;RANGE=THISANDFUTURE:19960120T120000Z
This default data type for this property is DATE-TIME. The data type
MAY be reset to DATE.
4.6.26 Recurrence Rule
This property is identified by the property name RRULE. This property
defines a rule or repeating pattern for a recurring events, to-dos,
or time zone definitions. The property MAY be specified in the
"VEVENT", "VTODO", "VJOURNAL" or "VTIMEZONE" calendar components. The
data type for this property is RECUR.
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.
This property is defined by the following notation:
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rrule = "RRULE" ":" [WSP] recur CRLF
Examples of this property include the following. All examples assume
the Eastern United States time zone.
Daily for 10 occurrences:
DTSTART:19970902T090000-0400
RRULE:FREQ=DAILY;COUNT=10
==> (1997 9AM EDT)September 2-11
Daily until 12/24/97:
DTSTART:19970902T090000-0400
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:19970902T090000-0400
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:19970902T090000-0400
RRULE:FREQ=DAILY;INTERVAL=10;COUNT=5
==> (1997 9AM EDT)September 2,12,22;October 2,12
Everyday in January, for 3 years:
DTSTART:19980101T090000-0400
RRULE:FREQ=YEARLY;UNTIL:20000131T090000-0400;BYMONTH=1;BYDAY=SU,
MO,TU,WE,TH,FR,SA
or
RRULE:FREQ=DAILY;UNTIL:20000131T090000-0400;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:19970902T090000-0400
RRULE:FREQ=WEEKLY;COUNT=10
==> (1997 9AM EDT)September 2,9,16,23,30;October 7,14,21
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(1997 9AM EST)October 28;November 4
Weekly until 12/24/94
DTSTART:19970902T090000-0400
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:19970902T090000-0400
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:19970902T090000-0400
RRULE:FREQ=WEEKLY;UNTIL=19971007T000000-0400;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:19970902T090000-0400
RRULE:FREQ=WEEKLY;INTERVAL=2;UNTIL=19971224T000000-0400;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:19970902T090000-0400
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:
DTSTART:19970905T090000-0400
RRULE:FREQ=MONTHLY;COUNT=10;BYDAY=1FR
==> (1997 9AM EDT)September 5;October 3
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(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:19970905T090000-0400
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:19970907T090000-0400
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:19970922T090000-0400
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:19970928T090000-0400
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:19970902T090000-0400
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
Monthly on the first and last day of the month for 10 occurrences:
DTSTART:19970930T090000-0400
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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:19970910T090000-0400
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:19970902T090000-0400
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:19970610T090000-0400
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:19970310T090000-0400
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:
DTSTART:19970101T090000-0400
RRULE:FREQ=YEARLY;INTERVAL=3;COUNT=10;BYYEARDAY=1,100,200
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==> (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:19970519T090000-0400
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:19970512T090000-0400
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:19970313T090000-0400
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:19970605T090000-0400
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
...
Every Friday the 13th, forever:
DTSTART:19970902T090000-0400
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EXDATE:19970902T090000-0400
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:19970913T090000-0400
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:19961105T090000-0400
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:19970904T090000-0400
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:19970929T090000-0400
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
...
Every 3 hours from 9AM to 5PM on a specific day:
DTSTART:19970902T090000-0400
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RRULE:FREQ=HOURLY;INTERVAL=3;UNTIL=19970902T170000-0400
==> (September 2, 1997 EDT)09:00,12:00,15:00
Every 15 minutes for 6 occurrences:
DTSTART:19970902T090000-0400
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:19970902T090000-0400
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:19970902T090000-0400
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:19970805T090000-0400
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 reults...
DTSTART:19970805T090000-0400
RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=SU
==> (1997 EDT)August 5,17,19,31
4.6.27 Related To
This property is identified by the property name RELATED-TO. The
property is used to represent a relationship or reference between one
calendar component and another. The property MAY only be specified
once in the "VEVENT", "VTODO", "VJOURNAL" or "VFREEBUSY" calendar
components. 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.
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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. 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.
The property is defined by the following notation:
related = "RELATED-TO" [";" [WSP] relparam) ":" [WSP] uid CRLF
relparam = "RELTYPE" "="
"PARENT" ; Parent relationship. Default.
/ "CHILD" ; Child relationship.
/ "SIBLING" ; Sibling relationship.
The following is an example of this property:
RELATED-TO:
RELATED-TO:<19960401-080045-4000F192713-0052@host1.com>
The data type for this property is UID.
4.6.28 Repeat Count
This property is identified by the property name REPEAT. This
property defines the number of time the alarm should be repeated,
after the initial trigger.
The property is defined by the following notation:
repeatcnt = "REPEAT" ":" [WSP] integer CRLF
;Default is "0", zero.
The following is an example of this property:
REPEAT:4
The data type for the property is INTEGER.
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4.6.29 Request Status
This property is identified by the property name REQUEST-STATUS. This
property defines the status code returned for a scheduling request.
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 xx)
separated set of integers. For example, "3.1.1". The successive
levels of integers provide for a successive level of status code
granularity.
The property is defined by the following notation:
rstatus = "REQUEST-STATUS" *(";" [WSP] parameter) ":" [WSP]
statcode ";" [WSP] statdesc [";" [WSP] extdata]
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.
The following are some possible examples of this property (Note: The
BACKSLASH character escapement of separator characters in a property
value):
REQUEST-STATUS:2.0;Success
REQUEST-STATUS:3.1;Invalid property value;DTSTART:96-Apr-01
REQUEST-STATUS:2.8; Success\, repeating event ignored. Scheduled
as a single event.;RRULE\:FREQ=WEEKLY\;INTERVAL=2
REQUEST-STATUS:4.1;Event conflict. Date/time is busy.
REQUEST-STATUS:3.7;Invalid calendar user;ATTENDEE:
MAILTO:jsmith@host.com
The following are valid classes for the return status code.
Individual iCalendar object methods will define specific return
status codes for these classes.
|==============+===============================================|
| Short Return | Longer Return Status Description |
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| 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.|
| | Some sort of error occurred within the |
| | calendaring and scheduling service, not |
| | directly related to the request itself. |
|==============+===============================================|
4.6.30 Resources
This property is identified by the property name RESOURCES. This
property defines the equipment or resources needed for the event or
to-do. The property value is an arbitrary text. The property MAY only
be specified in the "VEVENT" or "VTODO" calendar component. More than
one resource MAY be specified as a list of resources separated by the
COMMA character (ASCII decimal 44).
The property is defined by the following notation:
resource = "RESOURCES" *(";" [WSP] parameter) ":" [WSP]
resvalist CRLF
resvalist = resvalue / resvalue "," [WSP] resvalist
resvalue = "CATERING" / "CHAIRS" / "COMPUTER PROJECTOR"
/ "EASEL" / "OVERHEAD PROJECTOR" / "SPEAKER PHONE"
/ "TABLE" / "TV" / "VCR" / "VIDEO PHONE" / "VEHICLE"
/ word
The following is an example of this property:
RESOURCES:EASEL,PROJECTOR,VCR
The data type for this property is TEXT.
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4.6.31 Sequence Number
This property is identified by the property name SEQUENCE. This
property defines the revision sequence of the calendar component used
in a request. The property MAY only be specified in a "VEVENT",
"VTODO", "VJOURNAL" or "VFREEBUSY" calendar component. 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"
The property is defined by the following notation:
sequence = "SEQUENCE" ":" [WSP] integer CRLF
;Default is "0".
The following is an example of this property:
SEQUENCE:1
The data type for this property is INTEGER.
4.6.32 Status
This property is identified by the property name STATUS. This
property defines the orignator's view of the overall status for the
calendar component. This property MAY only be specified in the
"VEVENT", "VTODO", "VJOURNAL" calendar components. The property is
used to specify the originator's view of the general consensus for
the event or the to-do. In addition, when specified in a group
scheduled to-do the property is used to specify the originator's view
of the completion status for the to-do. The property MAY also specify
whether the event or to-do has been cancelled.
The property is defined by the following notation:
status = "STATUS" ":" [WSP] statvalue CRLF
statvalue = "NEEDS-ACTION" ;Indicates to-do needs action.
/ "COMPLETED" ;Indicates to-do completed.
/ "IN-PROCESS" ;Indicates to-do in process of
;being completed.
/ "TENTATIVE" ;Indicates event or to-do is
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;tentative.
/ "CONFIRMED" ;Indicates event or to-do is
;definite.
/ "CANCELLED" ;Indicates event or to-do was
;cancelled.
The following is an example of this property:
STATUS:TENTATIVE
The data type for this property is TEXT.
4.6.33 Summary
This property is identified by the property name SUMMARY. This
property defines a short summary or subject for the calendar
component. The property MUST be specified in the "VEVENT", "VTODO"
and "VJOURNAL" calendar components. In addition, it MAY appear in the
"VALARM" calendar component.
The property is defined by the following notation:
summary = "SUMMARY" *(";" [WSP] parameter) ":" [WSP] text CRLF
The following is an example of this property:
SUMMARY:Department Party
The data type for this property is TEXT.
4.6.34 Time Transparency
This property is identified by the property name TRANSP. This
property defines whether an event is transparent or not to busy time
searches. This property MAY only be specified in a "VEVENT" calendar
component.
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
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:
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TRANSP:OPAQUE
The data type for this property is TEXT.
4.6.35 Time Zone Name
This property is identified by the property name TZNAME. This
property specifies the customary designation for a time zone
description. This property MAY only be specified in the "VTIMEZONE"
calendar component.
This property is defined by the following notation:
tzname = "TZNAME" *(";" [WSP] parameter) ":" [WSP] text CRLF
The following are examples of this property:
TZNAME: EST
TZNAME: PDT
The data type for this property is TEXT.
4.6.36 Time Zone Offset
This property is identified by the property name TZOFFSET. This
property specifies the offset from UTC for a time zone. This property
MAY 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.
The property is defined by the following notation:
tzoffset = "TZOFFSET" ":" [WSP] utc-offset CRLF
The following are examples of this property:
TZOFFSET:-0500
TZOFFSET:+0530
The data type for this property is UTC-OFFSET.
4.6.37 Uniform Resource Locator
This property is identified by the property name URL. This property
defines a Uniform Resource Locator (URL) associated with the
iCalendar object. This property MAY be specified once in the
"VEVENT", "VTODO", "VJOURNAL" and "VFREEBUSY" calendar components.
The property is defined by the following notation:
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url = "URL" ":" [WSP] uri CRLF
The following is an example of this property:
URL:http://abc.com/pub/calendars/jsmith/mytime.or3
The data type for this property is URI.
4.6.38 Unique Identifier
This property is identified by the property name UID. This property
defines the persistent, globally unique identifier for the calendar
component. The property MUST be specified in the "VEVENT", "VTODO",
"VJOURNAL" and "VFREEBUSY" calendar components.
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
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.
The property is defined by the following notation:
uid = "UID" ":" [WSP] text CRLF
The following is an example of this property:
UID:19960401T080045Z-4000F192713-0052@host1.com
This property is an important method for group scheduling
applications to match requests with later replies, modifications or
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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.
The data type for this property is TEXT.
4.6.39 Non-standard Properties
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.
The property is defined by the following notation:
extension = "X-" [vendorid] "-" word *(";" [WSP] param) ":"
[WSP] value-list CRLF
; Lines longer than 75 characters should be folded
vendorid = 3*char ;Vendor identification prefix text
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
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.
5. Recommended Practices
These recommended practices should be followed in order to assure
consistent handling of the following cases for an iCalendar object.
1.
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
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time, it MUST NOT be used to record busy time no matter what the
value for the "TRANSP" property.
2.
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., local time with UTC offset).
3.
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.
4.
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. 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.
6.1 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.
6.2 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.
6.2.1 Define the property
A property is defined by completing the following template.
To: ietf-calendar@imc.org
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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.
6.2.2 Post the Property definition
The property description MUST be posted to the new property
discussion list, ietf-calendar@imc.org.
6.2.3 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.
6.2.4 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)
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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.
6.3 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.
7. File extension
The file extension of "vcs" is to be used to designate a file
containing calendaring and scheduling information consistent with
this MIME content type.
8. Macintosh File Type Code
The file type code of "vcal" 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.
9. References
The following document are referred to within this memo.
[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, October 1997, http://www.imc.org/draft-ietf-calsch-
imip-03.txt.
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[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, October 1997, http://www.imc.org/draft-ietf-calsch-
itip-02.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.
[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.
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[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.versit.com/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.
10. 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.
11. Author's Address
The following address information is provided in a MIME-VCARD,
Electronic Business Card, format.
The authors of this draft are:
BEGIN:VCARD
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
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BEGIN:VCARD
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
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
12. iCalendar object Examples
The following examples are provided as an informational source of
illustrative iCalendar objects consistent with this content type.
The following iCalendar object is specified as the content of a MIME
message. The example demonstrates a possible meeting request between
the originator and recipient of the message.
TO:jsmith@host1.com
FROM:jdoe@host1.com
MIME-VERSION:1.0
MESSAGE-ID:
CONTENT-TYPE:text/calendar;method=request
BEGIN:VCALENDAR
METHOD:REQUEST
PRODID:-//xyz Corp//NONSGML PDA Calendar Verson 1.0//EN
VERSION:2.0
BEGIN:VEVENT
DTSTAMP:19960704T120000Z
DTSTART:19960918T143000Z
DTEND:19960920T220000Z
CATEGORIES:CONFERENCE,PROJECT
SUMMARY:Networld+Interop Conference
DESCRIPTION:Networld+Interop Conference
and Exhibit\nAtlanta World Congress Center\n
Atlanta, Georgia
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END:VEVENT
END:VCALENDAR
The following example message issues a meeting request that does not
require any reply. The message is sent as a singular "text/calendar"
content type, body part.
From: jsmith@host1.com
To: ietf-calendar@imc.org
Subject: First IETF-Calendar Working Group Meeting
MIME-Version: 1.0
Message-ID:
Content-Type: text/calendar;method=request
BEGIN:VCALENDAR
METHOD:REQUEST
PRODID:-//RDU Software//NONSGML HandCal//EN
VERSION:2.0
BEGIN:VEVENT
DTSTAMP:19961022T133000Z
ATTENDEE;EXPECT=REQUEST:MAILTO:ietf-calendar@imc.org
DESCRIPTION:First IETF-Calendaring and Scheduling Working Group
Meeting
CATEGORIES:MEETING
CLASS:PUBLIC
CREATED:19961022T083000
SUMMARY:IETF Calendaring Working Group Meeting
DTSTART:19961210T210000Z
DTEND:19961210T220000Z
LOCATION:San Jose, CA - Fairmont Hotel
UID:guid-1.host1.com
END:VEVENT
END:VCALENDAR
The following is an example of a MIME message with a single body part
consisting of a text/calendar content type. The message specifies a
meeting request between the originator and recipient of the message.
TO:jsmith@host1.com
FROM:jdoe@host1.com
MIME-VERSION:1.0
MESSAGE-ID:
CONTENT-TYPE:text/calendar;method=request
BEGIN:VCALENDAR
METHOD:REQUEST
VERSION:2.0
PRODID:-//ABC Corporation//NONSGML My Product//EN
BEGIN:VEVENT
DTSTAMP:19970324T1200Z
SEQUENCE:0
UID:19970324T080045Z-4000F192713-0052@host1.com
ATTENDEE;EXPECT=REQUEST:MAILTO:jsmith@host1.com
DTSTART:19970324T123000Z
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DTEND:19970324T210000Z
CATEGORIES:CONFERENCE,PROJECT
CLASS:PUBLIC
SUMMARY:Calendaring Interop Conference
DESCRIPTION:Calendaring Interop Conference and Exhibit\n
Atlanta, Georgia
LOCATION:Atlanta World Congress Center
ATTACH;VALUE=URI:file:///xyzCorp.com/conf/bkgrnd.ps
END:VEVENT
END:VCALENDAR
Example of a reply to the above request, accepting the meeting.
TO:jdoe@host1.com
FROM:jsmith@host1.com
MIME-VERSION:1.0
MESSAGE-ID:
CONTENT-TYPE:text/calendar;method=reply
BEGIN:VCALENDAR
METHOD:REPLY
VERSION:2.0
PRODID:-//ABC Corporation//NONSGML My Product//EN
BEGIN:VEVENT
DTSTAMP:19970324T120000Z
SEQUENCE:0
UID:19970324T080045Z-4000F192713-0052@host1.com
ATTENDEE;STATUS=ACCEPTED;EXPECT=REQUEST:MAILTO:jsmith@host1.com
END:VEVENT
END:VCALENDAR
An example of a meeting cancelation:
TO:jsmith@host1.com
FROM:jdoe@host1.com
MIME-VERSION:1.0
MESSAGE-ID:
CONTENT-TYPE:text/calendar;method=cancel
BEGIN:VCALENDAR
METHOD:CANCEL
VERSION:2.0
PRODID:-//ABC Corporation//NONSGML My Product//EN
BEGIN:VEVENT
DTSTAMP:19970324T120000Z
UID:19970324T080045Z-4000F192713-0052@host1.com
END:VEVENT
END:VCALENDAR
13. Full Copyright Statement
"Copyright (C) The Internet Society (date). All Rights Reserved.
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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
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