COMP-ID

This property uniquely identifies a component among all its siblings of the same type.

TEXT, also see Format Definition for value restrictions.

The property can be specified once in a calendar component.

IANA and non-standard property parameters can be specified on this property.

A calendar component may embed multiple components of the same type. For example, a VEVENT component may embed multiple VALARM components. To distinguish these VALARMs among all global instances of VALARM calendar components, an application may choose to assign a uniquely global UID to each of them. However, some applications or formats such as JSCalendar, do not require globally uniqueness. Instead, they only require uniqueness among all instances of calendar components within one parent component. This is what the COMP-ID property is for.

The COMP-ID property identifies a component among all of its siblings of the same type. A valid COMP-ID value must be of 1 and a maximum of 255 octets in size, and it MUST only contain the ASCII alphanumeric characters ( A-Za-z0-9), hyphen (-), and underscore (_). The identifier only has the purpose to uniquely identify siblings, its value has no other meaning. If an application makes use of COMP-ID it SHOULD assign a unique identifier to each sibling component of the same type within their parent component. The same identifier MAY be used for components of a different type, and it MAY also be assigned to a same-typed component that is not a sibling.

Resolving duplicate identifier conflicts is specific to the application. Similarly, handling components where some but not all siblings have a COMP-ID is assigned, is application-specific.

This property is defined by the following notation:

comp-id  = "COMP-ID" comp-id-param ":" comp-id-value CRLF

comp-id-value  = 1*255(ALPHA / DIGIT / "-"/ "_")

comp-id-param  = *(";" other-param)

COMP-ID:m2398

SHOW-WITHOUT-TIME

This property indicates if an event or task should be displayed with time information.

BOOLEAN

The property can be specified once in the VEVENT, VTODO or VJOURNAL calendar components.

IANA and non-standard property parameters can be specified on this property.

This indicates that the time is not important to display to the user when rendering this calendar object. An example of this is an event that conceptually occurs all day or across multiple days, such as “New Year’s Day” or “Italy Vacation”. While the time component is important for free-busy calculations and checking for scheduling clashes, calendars may choose to omit displaying it and/or display the object separately to other objects to enhance the user’s view of their schedule.

This property is defined by the following notation:

show-without-time  = "SHOW-WITHOUT-TIME" show-without-time-param
                     ":" boolean CRLF

show-without-time-param  = *(";" other-param)

SHOW-WITHOUT-TIME:TRUE

The default value type is FLOAT, where the value MUST be two SEMICOLON-separated FLOAT values. The value type can also be set to URI to indicate geo: encoded coordinates.

VALUE

When the property value is a URI in the geo: scheme, then the VALUE property parameter MUST be set to URI.

This property is defined by the following notation:

geo   = "GEO" geoparam ( ":" geovalue ) /
                       (
                         ";" "VALUE" "=" "URI"
                         ":"  uri ; uri MUST be in the geo: scheme
                       )
                       CRLF

geoparam   = *(";" other-param)

geovalue   = float ";" float
       ;Latitude and Longitude components

GEO:37.386013;-122.082932
GEO;VALUE=URI:geo:48.198634,16.371648;crs=wgs84;u=40

CONTENT-ID

This parameter identifies an attachment contents for use with styled descriptions.

cid-param  = "CONTENT-ID" "=" DQUOTE uri DQUOTE
               ; uri must be a cid-url defined in <<RFC8288>>

This parameter MAY be set on an “ATTACH” or “IMAGE” property. It assigns the property an identifier that MUST be unique within the calendar component. A calendar component MAY include a STYLED-DESCRIPTION property as specified in IETF RFC 9073, Section 6.5, and MAY contain HTML text. URLs in the “cid:” scheme referred to by images and other data within that HTML description can be resolved to calendar component attachments having that content-id.

IMAGE;CONTENT-ID="cid:foo@bar.net":
 data:image/jpeg;base64,SGVsbG8sIFdvcmxk..

STYLED-DESCRIPTION;VALUE=TEXT;FMTTYPE=text/html:
  <html><body><img src="cid:foo@bar.net" alt="foo"/></body></html>

INVITED-BY

This parameter specifies which calendar address user invited another.

inviteby-param  = "INVITED-BY" "=" DQUOTE cal-address DQUOTE

This parameter MAY be set on an “ATTENDEE” property, specified in IETF RFC 5545, Section 3.8.4.1. If set, it identifies the participant that invited the calendar user represented by the ATTENDEE property to the calendar component.

ATTENDEE;INVITED-BY="inviter@example.com":invitee@example.com

LINK-REL

This parameter defines how an attachment relates to calendar component.

linkrel-param  = "LINK-REL" "=" paramtext
                   ; one of Link Relation Types registered in
                   ; the IANA Link Relations Registry (<<RFC8288>>)

This parameter MAY be set on an “ATTACH” or “IMAGE” property. It indicates how the contents of the attachment or image relate to the calendar component this property is part of. For the list of available relations, see the Link Relation Types in the IANA Link Relations Registry IETF RFC 8288.

ATTACH;LINK-REL=payment:https://example.com/donate

PROP-ID

This parameter identifies a property among all its siblings of the same type.

prop-id-param  = "PROP-ID" "=" 1*255(ALPHA / DIGIT / "-"/ "_")

This parameter uniquely identifies a property among all of its siblings with the same name within a calendar component. A valid PROP-ID value must be of 1 and a maximum of 255 octets in size, and it MUST only contain the ASCII alphanumeric characters ( A-Za-z0-9), hyphen ( -), and underscore (_). The identifier only has the purpose to uniquely identify siblings, its value has no other meaning. If an application makes use of PROP-ID it SHOULD assign a unique identifier to each sibling property of the same name within their embedding component. The same identifier MAY be used for properties of a different name, and it MAY also be assigned to a same-named property that is not a sibling.

Resolving duplicate identifier conflicts is specific to the application. Similarly, handling properties where some but not all siblings have a PROP-ID is assigned, is application-specific.

ATTACH;PROP-ID=a983:https://example.com/something