4.8.4.4 Recurrence ID
Basic Definition | Description| | Example
Basic Definition
- Property Name
- RECURRENCE-ID
- Purpose
- This property is used in conjunction with the "UID" and "SEQUENCE" property to identify a specific instance of a recurring "VEVENT", "VTODO" or "VJOURNAL" calendar component. The property value is the effective value of the "DTSTART" property of the recurrence instance.
- Value Type
- The default value type for this property is DATE-TIME. The time format can be any of the valid forms defined for a DATE-TIME value type. See DATE-TIME value type definition for specific interpretations of the various forms. The value type can be set to DATE.
- Property Parameters
- Non-standard property, value data type, time zone identifier and recurrence identifier range parameters can be specified on this property.
- Conformance
- This property can be specified in an iCalendar object containing a recurring calendar component.
Description
The full range of calendar components specified by a recurrence set is referenced by referring to just the "UID" property value corresponding to the calendar component. The "RECURRENCE-ID" property allows the reference to an individual instance within the recurrence set.
If the value of the "DTSTART" property is a DATE type value, then the value MUST be the calendar date for the recurrence instance.
The date/time value is set to the time when the original recurrence instance would occur; meaning that if the intent is to change a Friday meeting to Thursday, the date/time is still set to the original Friday meeting.
The "RECURRENCE-ID" property is used in conjunction with the "UID" and "SEQUENCE" property to identify a particular instance of a recurring event, to-do or journal. For a given pair of "UID" and "SEQUENCE" property values, the "RECURRENCE-ID" value for a recurrence instance is fixed. When the definition of the recurrence set for a calendar component changes, and hence the "SEQUENCE" property value changes, the "RECURRENCE-ID" for a given recurrence instance might also change.The "RANGE" parameter is used to specify the effective range of recurrence instances from the instance specified by the "RECURRENCE-ID" property value. The default value for the range parameter is the single recurrence instance only. The value can also be "THISANDPRIOR" to indicate a range defined by the given recurrence instance and all prior instances or the value can be "THISANDFUTURE" to indicate a range defined by the given recurrence instance and all subsequent instances.
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