for the range parameter is the single recurrence instance only. The
value can also be "THISANDPRIOR" to indicate a range defined by the
given recurrence instance and all prior instances or the value can be
"THISANDFUTURE" to indicate a range defined by the given recurrence
instance and all subsequent instances.
Format Definition: The property is defined by the following notation:
recurid = "RECURRENCE-ID" ridparam ":" ridval CRLF
ridparam = *(
; the following are optional,
; but MUST NOT occur more than once
(";" "VALUE" "=" ("DATE-TIME" / "DATE)) /
(";" tzidparam) / (";" rangeparam) /
; the following is optional,
; and MAY occur more than once
(";" xparam)
)
ridval = date-time / date
;Value MUST match value type
Example: The following are examples of this property:
RECURRENCE-ID;VALUE=DATE:19960401
RECURRENCE-ID;RANGE=THISANDFUTURE:19960120T120000Z
4.8.4.5 Related To
Property Name: RELATED-TO
Purpose: The property is used to represent a relationship or
reference between one calendar component and another.
Value Type: TEXT
Property Parameters: Non-standard and relationship type property
parameters can be specified on this property.
Conformance: The property can be specified one or more times in the
"VEVENT", "VTODO" or "VJOURNAL" calendar components.
Description: The property value consists of the persistent, globally
unique identifier of another calendar component. This value would be
represented in a calendar component by the "UID" property.
By default, the property value points to another calendar component
that has a PARENT relationship to the referencing object. The
"RELTYPE" property parameter is used to either explicitly state the
default PARENT relationship type to the referenced calendar component
or to override the default PARENT relationship type and specify
either a CHILD or SIBLING relationship. The PARENT relationship
indicates that the calendar component is a subordinate of the
referenced calendar component. The CHILD relationship indicates that
the calendar component is a superior of the referenced calendar
component. The SIBLING relationship indicates that the calendar
component is a peer of the referenced calendar component.
Changes to a calendar component referenced by this property can have
an implicit impact on the related calendar component. For example, if
a group event changes its start or end date or time, then the
related, dependent events will need to have their start and end dates
changed in a corresponding way. Similarly, if a PARENT calendar
component is canceled or deleted, then there is an implied impact to
the related CHILD calendar components. This property is intended only
to provide information on the relationship of calendar components. It
is up to the target calendar system to maintain any property
implications of this relationship.
Format Definition: The property is defined by the following notation:
related = "RELATED-TO" [relparam] ":" text CRLF
relparam = *(
; the following is optional,
; but MUST NOT occur more than once
(";" reltypeparam) /
; the following is optional,
; and MAY occur more than once
(";" xparm)
)
The following is an example of this property:
RELATED-TO:<jsmith.part7.19960817T083000.xyzMail@host3.com>
RELATED-TO:<19960401-080045-4000F192713-0052@host1.com>
4.8.4.6 Uniform Resource Locator
Property Name: URL
Purpose: This property defines a Uniform Resource Locator (URL)
associated with the iCalendar object.
Value Type: URI
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: This property can be specified once in the "VEVENT",
"VTODO", "VJOURNAL" or "VFREEBUSY" calendar components.
Description: This property may be used in a calendar component to
convey a location where a more dynamic rendition of the calendar
information associated with the calendar component can be found. This
memo does not attempt to standardize the form of the URI, nor the
format of the resource pointed to by the property value. If the URL
property and Content-Location MIME header are both specified, they
MUST point to the same resource.
Format Definition: The property is defined by the following notation:
url = "URL" urlparam ":" uri CRLF
urlparam = *(";" xparam)
Example: The following is an example of this property:
URL:http://abc.com/pub/calendars/jsmith/mytime.ics
4.8.4.7 Unique Identifier
Property Name: UID
Purpose: This property defines the persistent, globally unique
identifier for the calendar component.
Value Type: TEXT
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: The property MUST be specified in the "VEVENT", "VTODO",
"VJOURNAL" or "VFREEBUSY" calendar components.
Description: The UID itself MUST be a globally unique identifier. The
generator of the identifier MUST guarantee that the identifier is
unique. There are several algorithms that can be used to accomplish
this. The identifier is RECOMMENDED to be the identical syntax to the
[RFC822] 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.
This property is an important method for group scheduling
applications to match requests with later replies, modifications or
deletion requests. Calendaring and scheduling applications MUST
generate this property in "VEVENT", "VTODO" and "VJOURNAL" calendar
components to assure interoperability with other group scheduling
applications. This identifier is created by the calendar system that
generates an iCalendar object.
Implementations MUST be able to receive and persist values of at
least 255 characters for this property.
Format Definition: The property is defined by the following notation:
uid = "UID" uidparam ":" text CRLF
uidparam = *(";" xparam)
Example: The following is an example of this property:
UID:19960401T080045Z-4000F192713-0052@host1.com
4.8.5 Recurrence Component Properties
The following properties specify recurrence information in calendar
components.
4.8.5.1 Exception Date/Times
Property Name: EXDATE
Purpose: This property defines the list of date/time exceptions for a
recurring calendar component.
Value Type: The default value type for this property is DATE-TIME.
The value type can be set to DATE.
Property Parameters: Non-standard, value data type and time zone
identifier property parameters can be specified on this property.
Conformance: This property can be specified in an iCalendar object
that includes a recurring calendar component.
Description: The exception dates, if specified, are used in computing
the recurrence set. The recurrence set is the complete set of
recurrence instances for a calendar component. The recurrence set is
generated by considering the initial "DTSTART" property along with
the "RRULE", "RDATE", "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 can 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 then 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 can be used to exclude the value specified in
"DTSTART". However, in such cases the original "DTSTART" date MUST
still be maintained by the calendaring and scheduling system because
the original "DTSTART" value has inherent usage dependencies by other
properties such as the "RECURRENCE-ID".
Format Definition: The property is defined by the following notation:
exdate = "EXDATE" exdtparam ":" exdtval *("," exdtval) CRLF
exdtparam = *(
; the following are optional,
; but MUST NOT occur more than once
(";" "VALUE" "=" ("DATE-TIME" / "DATE")) /
(";" tzidparam) /
; the following is optional,
; and MAY occur more than once
(";" xparam)
)
exdtval = date-time / date
;Value MUST match value type
Example: The following is an example of this property:
EXDATE:19960402T010000Z,19960403T010000Z,19960404T010000Z
4.8.5.2 Exception Rule
Property Name: EXRULE
Purpose: This property defines a rule or repeating pattern for an
exception to a recurrence set.
Value Type: RECUR
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: This property can be specified in "VEVENT", "VTODO" or
"VJOURNAL" calendar components.
Description: The exception rule, if specified, is used in computing
the recurrence set. The recurrence set is the complete set of
recurrence instances for a calendar component. The recurrence set is
generated by considering the initial "DTSTART" property along with
the "RRULE", "RDATE", "EXDATE" and "EXRULE" properties contained
within the iCalendar object. The "DTSTART" defines the first instance
in the recurrence set. Multiple instances of the "RRULE" and "EXRULE"
properties can 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 can be used to exclude the value specified in
"DTSTART". However, in such cases the original "DTSTART" date MUST
still be maintained by the calendaring and scheduling system because
the original "DTSTART" value has inherent usage dependencies by other
properties such as the "RECURRENCE-ID".
Format Definition: The property is defined by the following notation:
exrule = "EXRULE" exrparam ":" recur CRLF
exrparam = *(";" xparam)
Example: The following are examples of this property. Except every
other week, on Tuesday and Thursday for 4 occurrences:
EXRULE:FREQ=WEEKLY;COUNT=4;INTERVAL=2;BYDAY=TU,TH
Except daily for 10 occurrences:
EXRULE:FREQ=DAILY;COUNT=10
Except yearly in June and July for 8 occurrences:
EXRULE:FREQ=YEARLY;COUNT=8;BYMONTH=6,7
4.8.5.3 Recurrence Date/Times
Property Name: RDATE
Purpose: This property defines the list of date/times for a
recurrence set.
Value Type: The default value type for this property is DATE-TIME.
The value type can be set to DATE or PERIOD.
Property Parameters: Non-standard, value data type and time zone
identifier property parameters can be specified on this property.
Conformance: The property can be specified in "VEVENT", "VTODO",
"VJOURNAL" or "VTIMEZONE" calendar components.
Description: This property can appear along with the "RRULE" property
to define an aggregate set of repeating occurrences. When they both
appear in an iCalendar object, the recurring events are defined by
the union of occurrences defined by both the "RDATE" and "RRULE".
The recurrence dates, if specified, are used in computing the
recurrence set. The recurrence set is the complete set of recurrence
instances for a calendar component. The recurrence set is generated
by considering the initial "DTSTART" property along with the "RRULE",
"RDATE", "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 can 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/times which fall
within the union of start date/times generated by any specified
"EXRULE" and "EXDATE" properties. This implies that start date/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.
Format Definition: The property is defined by the following notation:
rdate = "RDATE" rdtparam ":" rdtval *("," rdtval) CRLF
rdtparam = *(
; the following are optional,
; but MUST NOT occur more than once
(";" "VALUE" "=" ("DATE-TIME" / "DATE" / "PERIOD")) /
(";" tzidparam) /
; the following is optional,
; and MAY occur more than once
(";" xparam)
)
rdtval = date-time / date / period
;Value MUST match value type
Example: The following are examples of this property:
RDATE:19970714T123000Z
RDATE;TZID=US-EASTERN:19970714T083000
RDATE;VALUE=PERIOD:19960403T020000Z/19960403T040000Z,
19960404T010000Z/PT3H
RDATE;VALUE=DATE:19970101,19970120,19970217,19970421
19970526,19970704,19970901,19971014,19971128,19971129,19971225
4.8.5.4 Recurrence Rule
Property Name: RRULE
Purpose: This property defines a rule or repeating pattern for
recurring events, to-dos, or time zone definitions.
Value Type: RECUR
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: This property can be specified one or more times in
recurring "VEVENT", "VTODO" and "VJOURNAL" calendar components. It
can also be specified once in each STANDARD or DAYLIGHT sub-component
of the "VTIMEZONE" calendar component.
Description: The recurrence rule, if specified, is used in computing
the recurrence set. The recurrence set is the complete set of
recurrence instances for a calendar component. The recurrence set is
generated by considering the initial "DTSTART" property along with
the "RRULE", "RDATE", "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 can 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/times which fall within the union of start date/times generated
by any specified "EXRULE" and "EXDATE" properties. This implies that
start date/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 set. Any modified duration for
specific recurrences MUST be explicitly specified using the "RDATE"
property.
Format Definition: This property is defined by the following
notation:
rrule = "RRULE" rrulparam ":" recur CRLF
rrulparam = *(";" xparam)
Example: All examples assume the Eastern United States time zone.
Daily for 10 occurrences:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;COUNT=10
==> (1997 9:00 AM EDT)September 2-11
Daily until December 24, 1997:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;UNTIL=19971224T000000Z
==> (1997 9:00 AM EDT)September 2-30;October 1-25
(1997 9:00 AM EST)October 26-31;November 1-30;December 1-23
Every other day - forever:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;INTERVAL=2
==> (1997 9:00 AM EDT)September2,4,6,8...24,26,28,30;
October 2,4,6...20,22,24
(1997 9:00 AM EST)October 26,28,30;November 1,3,5,7...25,27,29;
Dec 1,3,...
Every 10 days, 5 occurrences:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;INTERVAL=10;COUNT=5
==> (1997 9:00 AM EDT)September 2,12,22;October 2,12
Everyday in January, for 3 years:
DTSTART;TZID=US-Eastern:19980101T090000
RRULE:FREQ=YEARLY;UNTIL=20000131T090000Z;
BYMONTH=1;BYDAY=SU,MO,TU,WE,TH,FR,SA
or
RRULE:FREQ=DAILY;UNTIL=20000131T090000Z;BYMONTH=1
==> (1998 9:00 AM EDT)January 1-31
(1999 9:00 AM EDT)January 1-31
(2000 9:00 AM EDT)January 1-31
Weekly for 10 occurrences
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;COUNT=10
==> (1997 9:00 AM EDT)September 2,9,16,23,30;October 7,14,21
(1997 9:00 AM EST)October 28;November 4
Weekly until December 24, 1997
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;UNTIL=19971224T000000Z
==> (1997 9:00 AM EDT)September 2,9,16,23,30;October 7,14,21
(1997 9:00 AM EST)October 28;November 4,11,18,25;
December 2,9,16,23
Every other week - forever:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;WKST=SU
==> (1997 9:00 AM EDT)September 2,16,30;October 14
(1997 9:00 AM EST)October 28;November 11,25;December 9,23
(1998 9:00 AM EST)January 6,20;February
...
Weekly on Tuesday and Thursday for 5 weeks:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;UNTIL=19971007T000000Z;WKST=SU;BYDAY=TU,TH
or
RRULE:FREQ=WEEKLY;COUNT=10;WKST=SU;BYDAY=TU,TH
==> (1997 9:00 AM EDT)September 2,4,9,11,16,18,23,25,30;October 2
Every other week on Monday, Wednesday and Friday until December 24,
1997, but starting on Tuesday, September 2, 1997:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;UNTIL=19971224T000000Z;WKST=SU;
BYDAY=MO,WE,FR
==> (1997 9:00 AM EDT)September 2,3,5,15,17,19,29;October
1,3,13,15,17
(1997 9:00 AM EST)October 27,29,31;November 10,12,14,24,26,28;
December 8,10,12,22
Every other week on Tuesday and Thursday, for 8 occurrences:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=8;WKST=SU;BYDAY=TU,TH
==> (1997 9:00 AM EDT)September 2,4,16,18,30;October 2,14,16
Monthly on the 1st Friday for ten occurrences:
DTSTART;TZID=US-Eastern:19970905T090000
RRULE:FREQ=MONTHLY;COUNT=10;BYDAY=1FR
==> (1997 9:00 AM EDT)September 5;October 3
(1997 9:00 AM EST)November 7;Dec 5
(1998 9:00 AM EST)January 2;February 6;March 6;April 3
(1998 9:00 AM EDT)May 1;June 5
Monthly on the 1st Friday until December 24, 1997:
DTSTART;TZID=US-Eastern:19970905T090000
RRULE:FREQ=MONTHLY;UNTIL=19971224T000000Z;BYDAY=1FR
==> (1997 9:00 AM EDT)September 5;October 3
(1997 9:00 AM EST)November 7;December 5
Every other month on the 1st and last Sunday of the month for 10
occurrences:
DTSTART;TZID=US-Eastern:19970907T090000
RRULE:FREQ=MONTHLY;INTERVAL=2;COUNT=10;BYDAY=1SU,-1SU
==> (1997 9:00 AM EDT)September 7,28
(1997 9:00 AM EST)November 2,30
(1998 9:00 AM EST)January 4,25;March 1,29
(1998 9:00 AM EDT)May 3,31
Monthly on the second to last Monday of the month for 6 months:
DTSTART;TZID=US-Eastern:19970922T090000
RRULE:FREQ=MONTHLY;COUNT=6;BYDAY=-2MO
==> (1997 9:00 AM EDT)September 22;October 20
(1997 9:00 AM EST)November 17;December 22
(1998 9:00 AM EST)January 19;February 16
Monthly on the third to the last day of the month, forever:
DTSTART;TZID=US-Eastern:19970928T090000
RRULE:FREQ=MONTHLY;BYMONTHDAY=-3
==> (1997 9:00 AM EDT)September 28
(1997 9:00 AM EST)October 29;November 28;December 29
(1998 9:00 AM EST)January 29;February 26
...
Monthly on the 2nd and 15th of the month for 10 occurrences:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=2,15
==> (1997 9:00 AM EDT)September 2,15;October 2,15
(1997 9:00 AM EST)November 2,15;December 2,15
(1998 9:00 AM EST)January 2,15
Monthly on the first and last day of the month for 10 occurrences:
DTSTART;TZID=US-Eastern:19970930T090000
RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=1,-1
==> (1997 9:00 AM EDT)September 30;October 1
(1997 9:00 AM EST)October 31;November 1,30;December 1,31
(1998 9:00 AM EST)January 1,31;February 1
Every 18 months on the 10th thru 15th of the month for 10
occurrences:
DTSTART;TZID=US-Eastern:19970910T090000
RRULE:FREQ=MONTHLY;INTERVAL=18;COUNT=10;BYMONTHDAY=10,11,12,13,14,
15
==> (1997 9:00 AM EDT)September 10,11,12,13,14,15
(1999 9:00 AM EST)March 10,11,12,13
Every Tuesday, every other month:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MONTHLY;INTERVAL=2;BYDAY=TU
==> (1997 9:00 AM EDT)September 2,9,16,23,30
(1997 9:00 AM EST)November 4,11,18,25
(1998 9:00 AM EST)January 6,13,20,27;March 3,10,17,24,31
...
Yearly in June and July for 10 occurrences:
DTSTART;TZID=US-Eastern:19970610T090000
RRULE:FREQ=YEARLY;COUNT=10;BYMONTH=6,7
==> (1997 9:00 AM EDT)June 10;July 10
(1998 9:00 AM EDT)June 10;July 10
(1999 9:00 AM EDT)June 10;July 10
(2000 9:00 AM EDT)June 10;July 10
(2001 9:00 AM EDT)June 10;July 10
Note: Since none of the BYDAY, BYMONTHDAY or BYYEARDAY components
are specified, the day is gotten from DTSTART
Every other year on January, February, and March for 10 occurrences:
DTSTART;TZID=US-Eastern:19970310T090000
RRULE:FREQ=YEARLY;INTERVAL=2;COUNT=10;BYMONTH=1,2,3
==> (1997 9:00 AM EST)March 10
(1999 9:00 AM EST)January 10;February 10;March 10
(2001 9:00 AM EST)January 10;February 10;March 10
(2003 9:00 AM EST)January 10;February 10;March 10
Every 3rd year on the 1st, 100th and 200th day for 10 occurrences:
DTSTART;TZID=US-Eastern:19970101T090000
RRULE:FREQ=YEARLY;INTERVAL=3;COUNT=10;BYYEARDAY=1,100,200
==> (1997 9:00 AM EST)January 1
(1997 9:00 AM EDT)April 10;July 19
(2000 9:00 AM EST)January 1
(2000 9:00 AM EDT)April 9;July 18
(2003 9:00 AM EST)January 1
(2003 9:00 AM EDT)April 10;July 19
(2006 9:00 AM EST)January 1
Every 20th Monday of the year, forever:
DTSTART;TZID=US-Eastern:19970519T090000
RRULE:FREQ=YEARLY;BYDAY=20MO
==> (1997 9:00 AM EDT)May 19
(1998 9:00 AM EDT)May 18
(1999 9:00 AM EDT)May 17
...
Monday of week number 20 (where the default start of the week is
Monday), forever:
DTSTART;TZID=US-Eastern:19970512T090000
RRULE:FREQ=YEARLY;BYWEEKNO=20;BYDAY=MO
==> (1997 9:00 AM EDT)May 12
(1998 9:00 AM EDT)May 11
(1999 9:00 AM EDT)May 17
...
Every Thursday in March, forever:
DTSTART;TZID=US-Eastern:19970313T090000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=TH
==> (1997 9:00 AM EST)March 13,20,27
(1998 9:00 AM EST)March 5,12,19,26
(1999 9:00 AM EST)March 4,11,18,25
...
Every Thursday, but only during June, July, and August, forever:
DTSTART;TZID=US-Eastern:19970605T090000
RRULE:FREQ=YEARLY;BYDAY=TH;BYMONTH=6,7,8
==> (1997 9:00 AM EDT)June 5,12,19,26;July 3,10,17,24,31;
August 7,14,21,28
(1998 9:00 AM EDT)June 4,11,18,25;July 2,9,16,23,30;
August 6,13,20,27
(1999 9:00 AM EDT)June 3,10,17,24;July 1,8,15,22,29;
August 5,12,19,26
...
Every Friday the 13th, forever:
DTSTART;TZID=US-Eastern:19970902T090000
EXDATE;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MONTHLY;BYDAY=FR;BYMONTHDAY=13
==> (1998 9:00 AM EST)February 13;March 13;November 13
(1999 9:00 AM EDT)August 13
(2000 9:00 AM EDT)October 13
...
The first Saturday that follows the first Sunday of the month,
forever:
DTSTART;TZID=US-Eastern:19970913T090000
RRULE:FREQ=MONTHLY;BYDAY=SA;BYMONTHDAY=7,8,9,10,11,12,13
==> (1997 9:00 AM EDT)September 13;October 11
(1997 9:00 AM EST)November 8;December 13
(1998 9:00 AM EST)January 10;February 7;March 7
(1998 9:00 AM EDT)April 11;May 9;June 13...
...
Every four years, the first Tuesday after a Monday in November,
forever (U.S. Presidential Election day):
DTSTART;TZID=US-Eastern:19961105T090000
RRULE:FREQ=YEARLY;INTERVAL=4;BYMONTH=11;BYDAY=TU;BYMONTHDAY=2,3,4,
5,6,7,8
==> (1996 9:00 AM EST)November 5
(2000 9:00 AM EST)November 7
(2004 9:00 AM EST)November 2
...
The 3rd instance into the month of one of Tuesday, Wednesday or
Thursday, for the next 3 months:
DTSTART;TZID=US-Eastern:19970904T090000
RRULE:FREQ=MONTHLY;COUNT=3;BYDAY=TU,WE,TH;BYSETPOS=3
==> (1997 9:00 AM EDT)September 4;October 7
(1997 9:00 AM EST)November 6
The 2nd to last weekday of the month:
DTSTART;TZID=US-Eastern:19970929T090000
RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-2
==> (1997 9:00 AM EDT)September 29
(1997 9:00 AM EST)October 30;November 27;December 30
(1998 9:00 AM EST)January 29;February 26;March 30
...
Every 3 hours from 9:00 AM to 5:00 PM on a specific day:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=HOURLY;INTERVAL=3;UNTIL=19970902T170000Z
==> (September 2, 1997 EDT)09:00,12:00,15:00
Every 15 minutes for 6 occurrences:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MINUTELY;INTERVAL=15;COUNT=6
==> (September 2, 1997 EDT)09:00,09:15,09:30,09:45,10:00,10:15
Every hour and a half for 4 occurrences:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MINUTELY;INTERVAL=90;COUNT=4
==> (September 2, 1997 EDT)09:00,10:30;12:00;13:30
Every 20 minutes from 9:00 AM to 4:40 PM every day:
DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;BYHOUR=9,10,11,12,13,14,15,16;BYMINUTE=0,20,40
or
RRULE:FREQ=MINUTELY;INTERVAL=20;BYHOUR=9,10,11,12,13,14,15,16
==> (September 2, 1997 EDT)9:00,9:20,9:40,10:00,10:20,
... 16:00,16:20,16:40
(September 3, 1997 EDT)9:00,9:20,9:40,10:00,10:20,
...16:00,16:20,16:40
...
An example where the days generated makes a difference because of
WKST:
DTSTART;TZID=US-Eastern:19970805T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=MO
==> (1997 EDT)Aug 5,10,19,24
changing only WKST from MO to SU, yields different results...
DTSTART;TZID=US-Eastern:19970805T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=SU
==> (1997 EDT)August 5,17,19,31
4.8.6 Alarm Component Properties
The following properties specify alarm information in calendar
components.
4.8.6.1 Action
Property Name: ACTION
Purpose: This property defines the action to be invoked when an alarm
is triggered.
Value Type: TEXT
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: This property MUST be specified once in a "VALARM"
calendar component.
Description: Each "VALARM" calendar component has a particular type
of action associated with it. This property specifies the type of
action
Format Definition: The property is defined by the following notation:
action = "ACTION" actionparam ":" actionvalue CRLF
actionparam = *(";" xparam)
actionvalue = "AUDIO" / "DISPLAY" / "EMAIL" / "PROCEDURE"
/ iana-token / x-name
Example: The following are examples of this property in a "VALARM"
calendar component:
ACTION:AUDIO
ACTION:DISPLAY
ACTION:PROCEDURE
4.8.6.2 Repeat Count
Property Name: REPEAT
Purpose: This property defines the number of time the alarm should be
repeated, after the initial trigger.
Value Type: INTEGER
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: This property can be specified in a "VALARM" calendar
component.
Description: If the alarm triggers more than once, then this property
MUST be specified along with the "DURATION" property.
Format Definition: The property is defined by the following notation:
repeatcnt = "REPEAT" repparam ":" integer CRLF
;Default is "0", zero.
repparam = *(";" xparam)
Example: The following is an example of this property for an alarm
that repeats 4 additional times with a 5 minute delay after the
initial triggering of the alarm:
REPEAT:4
DURATION:PT5M
4.8.6.3 Trigger
Property Name: TRIGGER
Purpose: This property specifies when an alarm will trigger.
Value Type: The default value type is DURATION. The value type can be
set to a DATE-TIME value type, in which case the value MUST specify a
UTC formatted DATE-TIME value.
Property Parameters: Non-standard, value data type, time zone
identifier or trigger relationship property parameters can be
specified on this property. The trigger relationship property
parameter MUST only be specified when the value type is DURATION.
Conformance: This property MUST be specified in the "VALARM" calendar
component.
Description: Within the "VALARM" calendar component, this property
defines when the alarm will trigger. The default value type is
DURATION, specifying a relative time for the trigger of the alarm.
The default duration is relative to the start of an event or to-do
that the alarm is associated with. The duration can be explicitly set
to trigger from either the end or the start of the associated event
or to-do with the "RELATED" parameter. A value of START will set the
alarm to trigger off the start of the associated event or to-do. A
value of END will set the alarm to trigger off the end of the
associated event or to-do.
Either a positive or negative duration may be specified for the
"TRIGGER" property. An alarm with a positive duration is triggered
after the associated start or end of the event or to-do. An alarm
with a negative duration is triggered before the associated start or
end of the event or to-do.
The "RELATED" property parameter is not valid if the value type of
the property is set to DATE-TIME (i.e., for an absolute date and time
alarm trigger). If a value type of DATE-TIME is specified, then the
property value MUST be specified in the UTC time format. If an
absolute trigger is specified on an alarm for a recurring event or
to-do, then the alarm will only trigger for the specified absolute
date/time, along with any specified repeating instances.
If the trigger is set relative to START, then the "DTSTART" property
MUST be present in the associated "VEVENT" or "VTODO" calendar
component. If an alarm is specified for an event with the trigger set
relative to the END, then the "DTEND" property or the "DSTART" and
"DURATION' properties MUST be present in the associated "VEVENT"
calendar component. If the alarm is specified for a to-do with a
trigger set relative to the END, then either the "DUE" property or
the "DSTART" and "DURATION' properties MUST be present in the
associated "VTODO" calendar component.
Alarms specified in an event or to-do which is defined in terms of a
DATE value type will be triggered relative to 00:00:00 UTC on the
specified date. For example, if "DTSTART:19980205, then the duration
trigger will be relative to19980205T000000Z.
Format Definition: The property is defined by the following notation:
trigger = "TRIGGER" (trigrel / trigabs)
trigrel = *(
; the following are optional,
; but MUST NOT occur more than once
(";" "VALUE" "=" "DURATION") /
(";" trigrelparam) /
; the following is optional,
; and MAY occur more than once
(";" xparam)
) ":" dur-value
trigabs = 1*(
; the following is REQUIRED,
; but MUST NOT occur more than once
(";" "VALUE" "=" "DATE-TIME") /
; the following is optional,
; and MAY occur more than once
(";" xparam)
) ":" date-time
Example: A trigger set 15 minutes prior to the start of the event or
to-do.
TRIGGER:-P15M
A trigger set 5 minutes after the end of the event or to-do.
TRIGGER;RELATED=END:P5M
A trigger set to an absolute date/time.
TRIGGER;VALUE=DATE-TIME:19980101T050000Z
4.8.7 Change Management Component Properties
The following properties specify change management information in
calendar components.
4.8.7.1 Date/Time Created
Property Name: CREATED
Purpose: This property specifies the date and time that the calendar
information was created by the calendar user agent in the calendar
store.
Note: This is analogous to the creation date and time for a file
in the file system.
Value Type: DATE-TIME
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: The property can be specified once in "VEVENT", "VTODO"
or "VJOURNAL" calendar components.
Description: The date and time is a UTC value.
Format Definition: The property is defined by the following notation:
created = "CREATED" creaparam ":" date-time CRLF
creaparam = *(";" xparam)
Example: The following is an example of this property:
CREATED:19960329T133000Z
4.8.7.2 Date/Time Stamp
Property Name: DTSTAMP
Purpose: The property indicates the date/time that the instance of
the iCalendar object was created.
Value Type: DATE-TIME
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: This property MUST be included in the "VEVENT", "VTODO",
"VJOURNAL" or "VFREEBUSY" calendar components.
Description: The value MUST be specified in the UTC time format.
This property is also useful to protocols such as [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
particular calendar data in the calendar store was created and last
modified. This is different than when the iCalendar object
representation of the calendar service information was created or
last modified.
Format Definition: The property is defined by the following notation:
dtstamp = "DTSTAMP" stmparam ":" date-time CRLF
stmparam = *(";" xparam)
Example:
DTSTAMP:19971210T080000Z
4.8.7.3 Last Modified
Property Name: LAST-MODIFIED
Purpose: The property specifies the date and time that the
information associated with the calendar component was last revised
in the calendar store.
Note: This is analogous to the modification date and time for a
file in the file system.
Value Type: DATE-TIME
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: This property can be specified in the "EVENT", "VTODO",
"VJOURNAL" or "VTIMEZONE" calendar components.
Description: The property value MUST be specified in the UTC time
format.
Format Definition: The property is defined by the following notation:
last-mod = "LAST-MODIFIED" lstparam ":" date-time CRLF
lstparam = *(";" xparam)
Example: The following is are examples of this property:
LAST-MODIFIED:19960817T133000Z
4.8.7.4 Sequence Number
Property Name: SEQUENCE
Purpose: This property defines the revision sequence number of the
calendar component within a sequence of revisions.
Value Type: integer
Property Parameters: Non-standard property parameters can be
specified on this property.
Conformance: The property can be specified in "VEVENT", "VTODO" or
"VJOURNAL" calendar component.
Description: When a calendar component is created, its sequence
number is zero (US-ASCII decimal 48). It is monotonically incremented
by the "Organizer's" CUA each time the "Organizer" makes a
significant revision to the calendar component. When the "Organizer"
makes changes to one of the following properties, the sequence number
MUST be incremented:
. "DTSTART"
. "DTEND"
. "DUE"
. "RDATE"
. "RRULE"
. "EXDATE"
. "EXRULE"
. "STATUS"
In addition, changes made by the "Organizer" to other properties can
also force the sequence number to be incremented. The "Organizer" CUA
MUST increment the sequence number when ever it makes changes to
properties in the calendar component that the "Organizer" deems will
jeopardize the validity of the participation status of the
"Attendees". For example, changing the location of a meeting from one
locale to another distant locale could effectively impact the
participation status of the "Attendees".
The "Organizer" includes this property in an iCalendar object that it
sends to an "Attendee" to specify the current version of the calendar
component.
The "Attendee" includes this property in an iCalendar object that it
sends to the "Organizer" to specify the version of the calendar
component that the "Attendee" is referring to.
A change to the sequence number is not the mechanism that an
"Organizer" uses to request a response from the "Attendees". The
"RSVP" parameter on the "ATTENDEE" property is used by the
"Organizer" to indicate that a response from the "Attendees" is
requested.
Format Definition: This property is defined by the following
notation:
seq = "SEQUENCE" seqparam ":" integer CRLF
; Default is "0"
seqparam = *(";" xparam)
Example: The following is an example of this property for a calendar
component that was just created by the "Organizer".
SEQUENCE:0
The following is an example of this property for a calendar component
that has been revised two different times by the "Organizer".
SEQUENCE:2
4.8.8 Miscellaneous Component Properties
The following properties specify information about a number of
miscellaneous features of calendar components.
4.8.8.1 Non-standard Properties
Property Name: Any property name with a "X-" prefix
Purpose: This class of property provides a framework for defining
non-standard properties.
Value Type: TEXT
Property Parameters: Non-standard and language property parameters
can be specified on this property.
Conformance: This property can be specified in any calendar
component.
Description: The MIME Calendaring and Scheduling Content Type
provides a "standard mechanism for doing non-standard things". This
extension support is provided for implementers to "push the envelope"
on the existing version of the memo. Extension properties are
specified by property and/or property parameter 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
can ignore them.
At present, there is no registration authority for names of extension
properties and property parameters. The data type for this property
is TEXT. Optionally, the data type can be any of the other valid data
types.
Format Definition: The property is defined by the following notation:
x-prop = x-name *(";" xparam) [";" languageparam] ":" text CRLF
; Lines longer than 75 octets should be folded
Example: The following might be the ABC vendor's extension for an
audio-clip form of subject property:
X-ABC-MMSUBJ;X-ABC-MMSUBJTYPE=wave:http://load.noise.org/mysubj.wav
4.8.8.2 Request Status
Property Name: REQUEST-STATUS
Purpose: This property defines the status code returned for a
scheduling request.
Value Type: TEXT
Property Parameters: Non-standard and language property parameters
can be specified on this property.
Conformance: The property can be specified in "VEVENT", "VTODO",
"VJOURNAL" or "VFREEBUSY" calendar component.
Description: This property is used to return status code information
related to the processing of an associated iCalendar object. The data
type for this property is TEXT.
The value consists of a short return status component, a longer
return status description component, and optionally a status-specific
data component. The components of the value are separated by the
SEMICOLON character (US-ASCII decimal 59).
The short return status is a PERIOD character (US-ASCII decimal 46)
separated 3-tuple of integers. For example, "3.1.1". The successive
levels of integers provide for a successive level of status code
granularity.
The following are initial classes for the return status code.
Individual iCalendar object methods will define specific return
status codes for these classes. In addition, other classes for the
return status code may be defined using the registration process
defined later in this memo.
|==============+===============================================|
| Short Return | Longer Return Status Description |
| Status Code | |
|==============+===============================================|
| 1.xx | Preliminary success. This class of status |
| | of status code indicates that the request has |
| | request has been initially processed but that |
| | completion is pending. |
|==============+===============================================|
| 2.xx | Successful. This class of status code |
| | indicates that the request was completed |
| | successfuly. However, the exact status code |
| | can indicate that a fallback has been taken. |
|==============+===============================================|
| 3.xx | Client Error. This class of status code |
| | indicates that the request was not successful.|
| | The error is the result of either a syntax or |
| | a semantic error in the client formatted |
| | request. Request should not be retried until |
| | the condition in the request is corrected. |
|==============+===============================================|
| 4.xx | Scheduling Error. This class of status code |
| | indicates that the request was not successful.|
| | Some sort of error occurred within the |
| | calendaring and scheduling service, not |
| | directly related to the request itself. |
|==============+===============================================|
Format Definition: The property is defined by the following notation:
rstatus = "REQUEST-STATUS" rstatparam ":"
statcode ";" statdesc [";" extdata]
rstatparam = *(
; the following is optional,
; but MUST NOT occur more than once
(";" languageparm) /
; the following is optional,
; and MAY occur more than once
(";" xparam)
)
statcode = 1*DIGIT *("." 1*DIGIT)
;Hierarchical, numeric return status code
statdesc = text
;Textual status description
extdata = text
;Textual exception data. For example, the offending property
;name and value or complete property line.
Example: The following are some possible examples of this property.
The COMMA and SEMICOLON separator characters in the property value
are BACKSLASH character escaped because they appear in a text value.
REQUEST-STATUS:2.0;Success
REQUEST-STATUS:3.1;Invalid property value;DTSTART:96-Apr-01
REQUEST-STATUS:2.8; Success\, repeating event ignored. Scheduled
as a single event.;RRULE:FREQ=WEEKLY\;INTERVAL=2
REQUEST-STATUS:4.1;Event conflict. Date/time is busy.
REQUEST-STATUS:3.7;Invalid calendar user;ATTENDEE:
MAILTO:jsmith@host.com
5 iCalendar Object Examples
The following examples are provided as an informational source of
illustrative iCalendar objects consistent with this content type.
The following example specifies a three-day conference that begins at
8:00 AM EDT, September 18, 1996 and end at 6:00 PM EDT, September 20,
1996.
BEGIN:VCALENDAR PRODID:-//xyz Corp//NONSGML PDA Calendar Verson
1.0//EN VERSION:2.0 BEGIN:VEVENT DTSTAMP:19960704T120000Z
UID:uid1@host.com ORGANIZER:MAILTO:jsmith@host.com
DTSTART:19960918T143000Z DTEND:19960920T220000Z STATUS:CONFIRMED
CATEGORIES:CONFERENCE SUMMARY:Networld+Interop Conference
DESCRIPTION:Networld+Interop Conference
and Exhibit\nAtlanta World Congress Center\n
Atlanta, Georgia END:VEVENT END:VCALENDAR
The following example specifies a group scheduled meeting that begin
at 8:30 AM EST on March 12, 1998 and end at 9:30 AM EST on March 12,
1998. The "Organizer" has scheduled the meeting with one or more
calendar users in a group. A time zone specification for Eastern
United States has been specified.
BEGIN:VCALENDAR
PRODID:-//RDU Software//NONSGML HandCal//EN
VERSION:2.0
BEGIN:VTIMEZONE
TZID:US-Eastern
BEGIN:STANDARD
DTSTART:19981025T020000
RDATE:19981025T020000
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19990404T020000