This is a purely informative rendering of an RFC that includes verified errata. This rendering may not be used as a reference.
The following 'Verified' errata have been incorporated in this document:
EID 6872, EID 6873
Internet Engineering Task Force (IETF) N. Jenkins
Request for Comments: 8984 R. Stepanek
Category: Standards Track Fastmail
ISSN: 2070-1721 July 2021
JSCalendar: A JSON Representation of Calendar Data
Abstract
This specification defines a data model and JSON representation of
calendar data that can be used for storage and data exchange in a
calendaring and scheduling environment. It aims to be an alternative
and, over time, successor to the widely deployed iCalendar data
format. It also aims to be unambiguous, extendable, and simple to
process. In contrast to the jCal format, which is also based on
JSON, JSCalendar is not a direct mapping from iCalendar but defines
the data model independently and expands semantics where appropriate.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8984.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction
1.1. Motivation and Relation to iCalendar and jCal
1.2. Notational Conventions
1.3. Type Signatures
1.4. Data Types
1.4.1. Id
1.4.2. Int
1.4.3. UnsignedInt
1.4.4. UTCDateTime
1.4.5. LocalDateTime
1.4.6. Duration
1.4.7. SignedDuration
1.4.8. TimeZoneId
1.4.9. PatchObject
1.4.10. Relation
1.4.11. Link
2. JSCalendar Objects
2.1. Event
2.2. Task
2.3. Group
3. Structure of JSCalendar Objects
3.1. Object Type
3.2. Normalization and Equivalence
3.3. Vendor-Specific Property Extensions, Values, and Types
4. Common JSCalendar Properties
4.1. Metadata Properties
4.1.1. @type
4.1.2. uid
4.1.3. relatedTo
4.1.4. prodId
4.1.5. created
4.1.6. updated
4.1.7. sequence
4.1.8. method
4.2. What and Where Properties
4.2.1. title
4.2.2. description
4.2.3. descriptionContentType
4.2.4. showWithoutTime
4.2.5. locations
4.2.6. virtualLocations
4.2.7. links
4.2.8. locale
4.2.9. keywords
4.2.10. categories
4.2.11. color
4.3. Recurrence Properties
4.3.1. recurrenceId
4.3.2. recurrenceIdTimeZone
4.3.3. recurrenceRules
4.3.4. excludedRecurrenceRules
4.3.5. recurrenceOverrides
4.3.6. excluded
4.4. Sharing and Scheduling Properties
4.4.1. priority
4.4.2. freeBusyStatus
4.4.3. privacy
4.4.4. replyTo
4.4.5. sentBy
4.4.6. participants
4.4.7. requestStatus
4.5. Alerts Properties
4.5.1. useDefaultAlerts
4.5.2. alerts
4.6. Multilingual Properties
4.6.1. localizations
4.7. Time Zone Properties
4.7.1. timeZone
4.7.2. timeZones
5. Type-Specific JSCalendar Properties
5.1. Event Properties
5.1.1. start
5.1.2. duration
5.1.3. status
5.2. Task Properties
5.2.1. due
5.2.2. start
5.2.3. estimatedDuration
5.2.4. percentComplete
5.2.5. progress
5.2.6. progressUpdated
5.3. Group Properties
5.3.1. entries
5.3.2. source
6. Examples
6.1. Simple Event
6.2. Simple Task
6.3. Simple Group
6.4. All-Day Event
6.5. Task with a Due Date
6.6. Event with End Time Zone
6.7. Floating-Time Event (with Recurrence)
6.8. Event with Multiple Locations and Localization
6.9. Recurring Event with Overrides
6.10. Recurring Event with Participants
7. Security Considerations
7.1. Expanding Recurrences
7.2. JSON Parsing
7.3. URI Values
7.4. Spam
7.5. Duplication
7.6. Time Zones
8. IANA Considerations
8.1. Media Type Registration
8.2. Creation of the "JSCalendar Properties" Registry
8.2.1. Preliminary Community Review
8.2.2. Submit Request to IANA
8.2.3. Designated Expert Review
8.2.4. Change Procedures
8.2.5. "JSCalendar Properties" Registry Template
8.2.6. Initial Contents for the "JSCalendar Properties"
Registry
8.3. Creation of the "JSCalendar Types" Registry
8.3.1. "JSCalendar Types" Registry Template
8.3.2. Initial Contents for the "JSCalendar Types" Registry
8.4. Creation of the "JSCalendar Enum Values" Registry
8.4.1. "JSCalendar Enum Values" Registry Property Template
8.4.2. "JSCalendar Enum Values" Registry Value Template
8.4.3. Initial Contents for the "JSCalendar Enum Values"
Registry
9. References
9.1. Normative References
9.2. Informative References
Acknowledgments
Authors' Addresses
1. Introduction
This document defines a data model for calendar event and task
objects, or groups of such objects, in electronic calendar
applications and systems. The format aims to be unambiguous,
extendable, and simple to process.
The key design considerations for this data model are as follows:
* The attributes of the calendar entry represented must be described
as simple key-value pairs. Simple events are simple to represent;
complex events can be modeled accurately.
* Wherever possible, there should be only one way to express the
desired semantics, reducing complexity.
* The data model should avoid ambiguities, which often lead to
interoperability issues between implementations.
* The data model should be generally compatible with the iCalendar
data format [RFC5545] [RFC7986] and extensions, but the
specification should add new attributes where the iCalendar format
currently lacks expressivity, and drop seldom-used, obsolete, or
redundant properties. This means translation with no loss of
semantics should be easy with most common iCalendar files.
* Extensions, such as new properties and components, should not
require updates to this document.
The representation of this data model is defined in the Internet JSON
(I-JSON) format [RFC7493], which is a strict subset of the JSON data
interchange format [RFC8259]. Using JSON is mostly a pragmatic
choice: its widespread use makes JSCalendar easier to adopt and the
ready availability of production-ready JSON implementations
eliminates a whole category of parser-related interoperability
issues, which iCalendar has often suffered from.
1.1. Motivation and Relation to iCalendar and jCal
The iCalendar data format [RFC5545], a widely deployed interchange
format for calendaring and scheduling data, has served calendaring
vendors for a long time but contains some ambiguities and pitfalls
that cannot be overcome without backward-incompatible changes.
Sources of implementation errors include the following:
* iCalendar defines various formats for local times, UTC, and dates.
* iCalendar requires custom time zone definitions within a single
calendar component.
* iCalendar's definition of recurrence rules is ambiguous and has
resulted in differing interpretations, even between experienced
calendar developers.
* The iCalendar format itself causes interoperability issues due to
misuse of CRLF-terminated strings, line continuations, and subtle
differences among iCalendar parsers.
In recent years, many new products and services have appeared that
wish to use a JSON representation of calendar data within their APIs.
The JSON format for iCalendar data, jCal [RFC7265], is a direct
mapping between iCalendar and JSON. In its effort to represent full
iCalendar semantics, it inherits all the same pitfalls and uses a
complicated JSON structure.
As a consequence, since the standardization of jCal, the majority of
implementations and service providers either kept using iCalendar or
came up with their own proprietary JSON representations, which are
incompatible with each other and often suffer from common pitfalls,
such as storing event start times in UTC (which become incorrect if
the time zone's rules change in the future). JSCalendar meets the
demand for JSON-formatted calendar data that is free of such known
problems and provides a standard representation as an alternative to
the proprietary formats.
1.2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The underlying format used for this specification is JSON.
Consequently, the terms "object" and "array" as well as the four
primitive types (strings, numbers, booleans, and null) are to be
interpreted as described in Section 1 of [RFC8259].
Some examples in this document contain "partial" JSON documents used
for illustrative purposes. In these examples, an ellipsis "..." is
used to indicate a portion of the document that has been removed for
compactness.
1.3. Type Signatures
Type signatures are given for all JSON values in this document. The
following conventions are used:
"*": The type is undefined (the value could be any type, although
permitted values may be constrained by the context of this value).
"String": This is the JSON string type.
"Number": This is the JSON number type.
"Boolean": This is the JSON boolean type.
"A[B]": The keys are all of type "A" and the values are all of type
"B" for a JSON object.
"A[]": There is an array of values of type "A"
"A|B": The value is either of type "A" or of type "B".
Other types may also be given; their representations are defined
elsewhere in this document.
1.4. Data Types
In addition to the standard JSON data types, the following data types
are used in this specification:
1.4.1. Id
Where "Id" is given as a data type, it means a "String" of at least 1
and a maximum of 255 octets in size, and it MUST only contain
characters from the "URL and Filename Safe" base64url alphabet, as
defined in Section 5 of [RFC4648], excluding the pad character ("=").
This means the allowed characters are the ASCII alphanumeric
characters ("A-Za-z0-9"), hyphen ("-"), and underscore ("_").
In many places in JSCalendar, a JSON map is used where the map keys
are of type Id and the map values are all the same type of object.
This construction represents an unordered set of objects, with the
added advantage that each entry has a name (the corresponding map
key). This allows for more concise patching of objects, and, when
applicable, for the objects in question to be referenced from other
objects within the JSCalendar object.
Unless otherwise specified for a particular property, there are no
uniqueness constraints on an Id value (other than, of course, the
requirement that you cannot have two values with the same key within
a single JSON map). For example, two Event objects might use the
same Ids in their respective "links" properties or, within the same
Event object, the same Id could appear in the "participants" and
"alerts" properties. These situations do not imply any semantic
connections among the objects.
1.4.2. Int
Where "Int" is given as a data type, it means an integer in the range
-2^53+1 <= value <= 2^53-1, the safe range for integers stored in a
floating-point double, represented as a JSON "Number".
1.4.3. UnsignedInt
Where "UnsignedInt" is given as a data type, it means an integer in
the range 0 <= value <= 2^53-1, represented as a JSON "Number".
1.4.4. UTCDateTime
This is a string in the "date-time" [RFC3339] format, with the
further restrictions that any letters MUST be in uppercase, and the
time offset MUST be the character "Z". Fractional second values MUST
NOT be included unless non-zero and MUST NOT have trailing zeros, to
ensure there is only a single representation for each date-time.
For example, "2010-10-10T10:10:10.003Z" is conformant, but
"2010-10-10T10:10:10.000Z" is invalid and is correctly encoded as
"2010-10-10T10:10:10Z".
1.4.5. LocalDateTime
This is a date-time string with no time zone/offset information. It
is otherwise in the same format as UTCDateTime, including fractional
seconds. For example, "2006-01-02T15:04:05" and
"2006-01-02T15:04:05.003" are both valid. The time zone to associate
with the LocalDateTime comes from the "timeZone" property of the
JSCalendar object (see Section 4.7.1). If no time zone is specified,
the LocalDateTime is "floating". Floating date-times are not tied to
any specific time zone. Instead, they occur in each time zone at the
given wall-clock time (as opposed to the same instant point in time).
A time zone may have a period of discontinuity, for example, a change
from standard time to daylight savings time. When converting local
date-times that fall in the discontinuity to UTC, the offset before
the transition MUST be used.
For example, in the America/Los_Angeles time zone, the date-time
2020-11-01T01:30:00 occurs twice: before the daylight savings time
(DST) transition with a UTC offset of -07:00 and again after the
transition with an offset of -08:00. When converting to UTC, we
therefore use the offset before the transition (-07:00), so it
becomes 2020-11-01T08:30:00Z.
Similarly, in the Australia/Melbourne time zone, the date-time
2020-10-04T02:30:00 does not exist; the clocks are moved forward one
hour for DST on that day at 02:00. However, such a value may appear
during calculations (see duration semantics in Section 1.4.6) or due
to a change in time zone rules (so it was valid when the event was
first created). Again, it is interpreted as though the offset before
the transition is in effect (+10:00); therefore, when converted to
UTC, we get 2020-10-03T16:30:00Z.
1.4.6. Duration
Where Duration is given as a type, it means a length of time
represented by a subset of the ISO 8601 duration format, as specified
by the following ABNF [RFC5234]:
dur-secfrac = "." 1*DIGIT
dur-second = 1*DIGIT [dur-secfrac] "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-day = 1*DIGIT "D"
dur-week = 1*DIGIT "W"
dur-cal = (dur-week [dur-day] / dur-day)
duration = "P" (dur-cal [dur-time] / dur-time)
In addition, the duration MUST NOT include fractional second values
unless the fraction is non-zero. Fractional second values MUST NOT
have trailing zeros to ensure there is only a single representation
for each duration.
A duration specifies an abstract number of weeks, days, hours,
minutes, and/or seconds. A duration specified using weeks or days
does not always correspond to an exact multiple of 24 hours. The
number of hours/minutes/seconds may vary if it overlaps a period of
discontinuity in the event's time zone, for example, a change from
standard time to daylight savings time. Leap seconds MUST NOT be
considered when adding or subtracting a duration to/from a
LocalDateTime.
To add a duration to a LocalDateTime:
1. Add any week or day components of the duration to the date. A
week is always the same as seven days.
2. If a time zone applies to the LocalDateTime, convert it to a
UTCDateTime following the semantics in Section 1.4.5.
3. Add any hour, minute, or second components of the duration (in
absolute time).
4. Convert the resulting UTCDateTime back to a LocalDateTime in the
time zone that applies.
To subtract a duration from a LocalDateTime, the steps apply in
reverse:
1. If a time zone applies to the LocalDateTime, convert it to UTC
following the semantics in Section 1.4.5.
2. Subtract any hour, minute, or second components of the duration
(in absolute time).
3. Convert the resulting UTCDateTime back to LocalDateTime in the
time zone that applies.
4. Subtract any week or day components of the duration from the
date.
5. If the resulting time does not exist on the date due to a
discontinuity in the time zone, use the semantics in
Section 1.4.5 to convert to UTC and back to get a valid
LocalDateTime.
These semantics match the iCalendar DURATION value type ([RFC5545],
Section 3.3.6).
1.4.7. SignedDuration
A SignedDuration represents a length of time that may be positive or
negative and is typically used to express the offset of a point in
time relative to an associated time. It is represented as a
Duration, optionally preceded by a sign character. It is specified
by the following ABNF:
signed-duration = ["+" / "-"] duration
A negative sign indicates a point in time at or before the associated
time; a positive or no sign indicates a time at or after the
associated time.
1.4.8. TimeZoneId
Where "TimeZoneId" is given as a data type, it means a "String" that
is either a time zone name in the IANA Time Zone Database [TZDB] or a
custom time zone identifier defined in the "timeZones" property (see
Section 4.7.2).
Where an IANA time zone is specified, the zone rules of the
respective zone records apply. Custom time zones are interpreted as
described in Section 4.7.2.
1.4.9. PatchObject
A PatchObject is of type "String[*]" and represents an unordered set
of patches on a JSON object. Each key is a path represented in a
subset of the JSON Pointer format [RFC6901]. The paths have an
implicit leading "/", so each key is prefixed with "/" before
applying the JSON Pointer evaluation algorithm.
A patch within a PatchObject is only valid if all of the following
conditions apply:
1. The pointer MUST NOT reference inside an array (i.e., you MUST
NOT insert/delete from an array; the array MUST be replaced in
its entirety instead).
2. All parts prior to the last (i.e., the value after the final
slash) MUST already exist on the object being patched.
3. There MUST NOT be two patches in the PatchObject where the
pointer of one is the prefix of the pointer of the other, e.g.,
"alerts/1/offset" and "alerts".
4. The value for the patch MUST be valid for the property being set
(of the correct type and obeying any other applicable
restrictions), or, if null, the property MUST be optional.
The value associated with each pointer determines how to apply that
patch:
* If null, remove the property from the patched object. If the key
is not present in the parent, this a no-op.
* If non-null, set the value given as the value for this property
(this may be a replacement or addition to the object being
patched).
A PatchObject does not define its own "@type" property (see
Section 4.1.1). An "@type" property in a patch MUST be handled as
any other patched property value.
Implementations MUST reject a PatchObject in its entirety if any of
its patches are invalid. Implementations MUST NOT apply partial
patches.
The PatchObject format is used to significantly reduce file size and
duplicated content when specifying variations to a common object,
such as with recurring events or when translating the data into
multiple languages. It can also better preserve semantic intent if
only the properties that should differ between the two objects are
patched. For example, if one person is not going to a particular
instance of a regularly scheduled event, in iCalendar, you would have
to duplicate the entire event in the override. In JSCalendar, this
is a small patch to show the difference. As only this property is
patched, if the location of the event is changed, the occurrence will
automatically still inherit this.
1.4.10. Relation
A Relation object defines the relation to other objects, using a
possibly empty set of relation types. The object that defines this
relation is the linking object, while the other object is the linked
object. A Relation object has the following properties:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be "Relation".
relation: "String[Boolean]" (optional, default: empty Object)
This describes how the linked object is related to the linking
object. The relation is defined as a set of relation types. If
empty, the relationship between the two objects is unspecified.
Keys in the set MUST be one of the following values, specified in
the property definition where the Relation object is used, a value
registered in the IANA "JSCalendar Enum Values" registry, or a
vendor-specific value (see Section 3.3):
"first": The linked object is the first in a series the linking
object is part of.
"next": The linked object is next in a series the linking object
is part of.
"child": The linked object is a subpart of the linking object.
"parent": The linking object is a subpart of the linked object.
The value for each key in the map MUST be true.
1.4.11. Link
A Link object represents an external resource associated with the
linking object. It has the following properties:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be "Link".
href: "String" (mandatory)
This is a URI [RFC3986] from which the resource may be fetched.
This MAY be a "data:" URL [RFC2397], but it is recommended that
the file be hosted on a server to avoid embedding arbitrarily
large data in JSCalendar object instances.
cid: "String" (optional)
This MUST be a valid "content-id" value according to the
definition of Section 2 of [RFC2392]. The value MUST be unique
within this Link object but has no meaning beyond that. It MAY be
different from the link id for this Link object.
contentType: "String" (optional)
This is the media type [RFC6838] of the resource, if known.
size: "UnsignedInt" (optional)
This is the size, in octets, of the resource when fully decoded
(i.e., the number of octets in the file the user would download),
if known. Note that this is an informational estimate, and
implementations must be prepared to handle the actual size being
quite different when the resource is fetched.
rel: "String" (optional)
This identifies the relation of the linked resource to the object.
If set, the value MUST be a relation type from the IANA "Link
Relations" registry [LINKRELS], as established in [RFC8288].
display: "String" (optional)
This describes the intended purpose of a link to an image. If
set, the "rel" property MUST be set to "icon". The value MUST be
one of the following values, another value registered in the IANA
"JSCalendar Enum Values" registry, or a vendor-specific value (see
Section 3.3):
"badge": an image meant to be displayed alongside the title of
the object
"graphic": a full image replacement for the object itself
"fullsize": an image that is used to enhance the object
"thumbnail": a smaller variant of "fullsize" to be used when
space for the image is constrained
title: "String" (optional)
This is a human-readable, plain-text description of the resource.
2. JSCalendar Objects
This section describes the calendar object types specified by
JSCalendar.
2.1. Event
Media type: "application/jscalendar+json;type=event"
An Event represents a scheduled amount of time on a calendar,
typically a meeting, appointment, reminder, or anniversary. It is
required to start at a certain point in time and typically has a non-
zero duration. Multiple participants may partake in the event at
multiple locations.
The @type (Section 4.1.1) property value MUST be "Event".
2.2. Task
Media type: "application/jscalendar+json;type=task"
A Task represents an action item, assignment, to-do item, or work
item. It may start and be due at certain points in time, take some
estimated time to complete, and recur, none of which is required.
The @type (Section 4.1.1) property value MUST be "Task".
2.3. Group
Media type: "application/jscalendar+json;type=group"
A Group is a collection of Event (Section 2.1) and/or Task
(Section 2.2) objects. Typically, objects are grouped by topic
(e.g., by keywords) or calendar membership.
The @type (Section 4.1.1) property value MUST be "Group".
3. Structure of JSCalendar Objects
A JSCalendar object is a JSON object [RFC8259], which MUST be valid
I-JSON (a stricter subset of JSON) [RFC7493]. Property names and
values are case sensitive.
The object has a collection of properties, as specified in the
following sections. Properties are specified as being either
mandatory or optional. Optional properties may have a default value
if explicitly specified in the property definition.
3.1. Object Type
JSCalendar objects MUST name their type in the "@type" property if
not explicitly specified otherwise for the respective object type. A
notable exception to this rule is the PatchObject (Section 1.4.9).
3.2. Normalization and Equivalence
JSCalendar aims to provide unambiguous definitions for value types
and properties but does not define a general normalization or
equivalence method for JSCalendar objects and types. This is because
the notion of equivalence might range from byte-level equivalence to
semantic equivalence, depending on the respective use case.
Normalization of JSCalendar objects is hindered because of the
following reasons:
* Custom JSCalendar properties may contain arbitrary JSON values,
including arrays. However, equivalence of arrays might or might
not depend on the order of elements, depending on the respective
property definition.
* Several JSCalendar property values are defined as URIs and media
types, but normalization of these types is inherently protocol and
scheme specific, depending on the use case of the equivalence
definition (see Section 6 of [RFC3986]).
Considering this, the definition of equivalence and normalization is
left to client and server implementations and to be negotiated by a
calendar exchange protocol or defined elsewhere.
3.3. Vendor-Specific Property Extensions, Values, and Types
Vendors MAY add additional properties to the calendar object to
support their custom features. To avoid conflict, the names of these
properties MUST be prefixed by a domain name controlled by the vendor
followed by a colon, e.g., "example.com:customprop". If the value is
a new JSCalendar object, it either MUST include an "@type" property,
or it MUST explicitly be specified to not require a type designator.
The type name MUST be prefixed with a domain name controlled by the
vendor.
Some JSCalendar properties allow vendor-specific value extensions.
Such vendor-specific values MUST be prefixed by a domain name
controlled by the vendor followed by a colon, e.g.,
"example.com:customrel".
Vendors are strongly encouraged to register any new property values
or extensions that are useful to other systems as well, rather than
use a vendor-specific prefix.
4. Common JSCalendar Properties
This section describes the properties that are common to the various
JSCalendar object types. Specific JSCalendar object types may only
support a subset of these properties. The object type definitions in
Section 5 describe the set of supported properties per type.
4.1. Metadata Properties
4.1.1. @type
Type: "String" (mandatory)
This specifies the type that this object represents. The allowed
value differs by object type and is defined in Sections 2.1, 2.2, and
2.3.
4.1.2. uid
Type: "String" (mandatory)
This is a globally unique identifier used to associate objects
representing the same event, task, group, or other object across
different systems, calendars, and views. For recurring events and
tasks, the UID is associated with the base object and therefore is
the same for all occurrences; the combination of the UID with a
"recurrenceId" identifies a particular instance.
The generator of the identifier MUST guarantee that the identifier is
unique. [RFC4122] describes a range of established algorithms to
generate universally unique identifiers (UUIDs). UUID version 4,
described in Section 4.4 of [RFC4122], is RECOMMENDED.
For compatibility with UIDs [RFC5545], implementations MUST be able
to receive and persist values of at least 255 octets for this
property, but they MUST NOT truncate values in the middle of a UTF-8
multi-octet sequence.
4.1.3. relatedTo
Type: "String[Relation]" (optional)
This relates the object to other JSCalendar objects. This is
represented as a map of the UIDs of the related objects to
information about the relation.
If an object is split to make a "this and future" change to a
recurrence, the original object MUST be truncated to end at the
previous occurrence before this split, and a new object is created to
represent all the occurrences after the split. A "next" relation
MUST be set on the original object's "relatedTo" property for the UID
of the new object. A "first" relation for the UID of the first
object in the series MUST be set on the new object. Clients can then
follow these UIDs to get the complete set of objects if the user
wishes to modify them all at once.
4.1.4. prodId
Type: "String" (optional)
This is the identifier for the product that last updated the
JSCalendar object. This should be set whenever the data in the
object is modified (i.e., whenever the "updated" property is set).
The vendor of the implementation MUST ensure that this is a globally
unique identifier, using some technique such as a Formal Public
Identifier (FPI) value, as defined in [ISO.9070.1991].
This property SHOULD NOT be used to alter the interpretation of a
JSCalendar object beyond the semantics specified in this document.
For example, it is not to be used to further the understanding of
nonstandard properties, a practice that is known to cause long-term
interoperability problems.
4.1.5. created
Type: "UTCDateTime" (optional)
This is the date and time this object was initially created.
4.1.6. updated
Type: "UTCDateTime" (mandatory)
This is the date and time the data in this object was last modified
(or its creation date/time if not modified since).
4.1.7. sequence
Type: "UnsignedInt" (optional, default: 0)
Initially zero, this MUST be incremented by one every time a change
is made to the object, except if the change only modifies the
"participants" property (see Section 4.4.6).
This is used as part of the iCalendar Transport-independent
Interoperability Protocol (iTIP) [RFC5546] to know which version of
the object a scheduling message relates to.
4.1.8. method
Type: "String" (optional)
This is the iTIP [RFC5546] method, in lowercase. This MUST only be
present if the JSCalendar object represents an iTIP scheduling
message.
4.2. What and Where Properties
4.2.1. title
Type: "String" (optional, default: empty String)
This is a short summary of the object.
4.2.2. description
Type: "String" (optional, default: empty String)
This is a longer-form text description of the object. The content is
formatted according to the "descriptionContentType" property.
4.2.3. descriptionContentType
Type: "String" (optional, default: "text/plain")
This describes the media type [RFC6838] of the contents of the
"description" property. Media types MUST be subtypes of type "text"
and SHOULD be "text/plain" or "text/html" [MEDIATYPES]. They MAY
include parameters, and the "charset" parameter value MUST be "utf-
8", if specified. Descriptions of type "text/html" MAY contain "cid"
URLs [RFC2392] to reference links in the calendar object by use of
the "cid" property of the Link object.
4.2.4. showWithoutTime
Type: "Boolean" (optional, default: false)
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.
Such events are also commonly known as "all-day" events.
4.2.5. locations
Type: "Id[Location]" (optional)
This is a map of location ids to Location objects, representing
locations associated with the object.
A Location object has the following properties. It MUST have at
least one property other than the "relativeTo" property.
@type: "String" (mandatory)
This specifies the type of this object. This MUST be "Location".
name: "String" (optional)
This is the human-readable name of the location.
description: "String" (optional)
This is the human-readable, plain-text instructions for accessing
this location. This may be an address, set of directions, door
access code, etc.
locationTypes: "String[Boolean]" (optional)
This is a set of one or more location types that describe this
location. All types MUST be from the "Location Types Registry"
[LOCATIONTYPES], as defined in [RFC4589]. The set is represented
as a map, with the keys being the location types. The value for
each key in the map MUST be true.
relativeTo: "String" (optional)
This specifies the relation between this location and the time of
the JSCalendar object. This is primarily to allow events
representing travel to specify the location of departure (at the
start of the event) and location of arrival (at the end); this is
particularly important if these locations are in different time
zones, as a client may wish to highlight this information for the
user.
This MUST be one of the following values, another value registered
in the IANA "JSCalendar Enum Values" registry, or a vendor-
specific value (see Section 3.3). Any value the client or server
doesn't understand should be treated the same as if this property
is omitted.
"start": The event/task described by this JSCalendar object
occurs at this location at the time the event/task starts.
"end": The event/task described by this JSCalendar object occurs
at this location at the time the event/task ends.
timeZone: "TimeZoneId" (optional)
This is a time zone for this location.
coordinates: "String" (optional)
This is a "geo:" URI [RFC5870] for the location.
links: "Id[Link]" (optional)
This is a map of link ids to Link objects, representing external
resources associated with this location, for example, a vCard or
image. If there are no links, this MUST be omitted (rather than
specified as an empty set).
4.2.6. virtualLocations
Type: "Id[VirtualLocation]" (optional)
This is a map of virtual location ids to VirtualLocation objects,
representing virtual locations, such as video conferences or chat
rooms, associated with the object.
A VirtualLocation object has the following properties.
@type: "String" (mandatory)
This specifies the type of this object. This MUST be
"VirtualLocation".
name: "String" (optional, default: empty String)
This is the human-readable name of the virtual location.
description: "String" (optional)
These are human-readable plain-text instructions for accessing
this virtual location. This may be a conference access code, etc.
uri: "String" (mandatory)
This is a URI [RFC3986] that represents how to connect to this
virtual location.
This may be a telephone number (represented using the "tel:"
scheme, e.g., "tel:+1-555-555-5555") for a teleconference, a web
address for online chat, or any custom URI.
features: "String[Boolean]" (optional)
A set of features supported by this virtual location. The set is
represented as a map, with the keys being the feature. The value
for each key in the map MUST be true.
The feature MUST be one of the following values, another value
registered in the IANA "JSCalendar Enum Values" registry, or a
vendor-specific value (see Section 3.3). Any value the client or
server doesn't understand should be treated the same as if this
feature is omitted.
audio: Audio conferencing
chat: Chat or instant messaging
feed: Blog or atom feed
moderator: Provides moderator-specific features
phone: Phone conferencing
screen: Screen sharing
video: Video conferencing
4.2.7. links
Type: "Id[Link]" (optional)
This is a map of link ids to Link objects, representing external
resources associated with the object.
Links with a rel of "enclosure" MUST be considered by the client to
be attachments for download.
Links with a rel of "describedby" MUST be considered by the client to
be alternative representations of the description.
Links with a rel of "icon" MUST be considered by the client to be
images that it may use when presenting the calendar data to a user.
The "display" property may be set to indicate the purpose of this
image.
4.2.8. locale
Type: "String" (optional)
This is the language tag, as defined in [RFC5646], that best
describes the locale used for the text in the calendar object, if
known.
4.2.9. keywords
Type: "String[Boolean]" (optional)
This is a set of keywords or tags that relate to the object. The set
is represented as a map, with the keys being the keywords. The value
for each key in the map MUST be true.
4.2.10. categories
Type: "String[Boolean]" (optional)
This is a set of categories that relate to the calendar object. The
set is represented as a map, with the keys being the categories
specified as URIs. The value for each key in the map MUST be true.
In contrast to keywords, categories are typically structured. For
example, a vendor owning the domain "example.com" might define the
categories "http://example.com/categories/sports/american-football"
and "http://example.com/categories/music/r-b".
4.2.11. color
Type: "String" (optional)
This is a color clients MAY use when displaying this calendar object.
The value is a color name taken from the set of names defined in
Section 4.3 of CSS Color Module Level 3 [COLORS] or an RGB value in
hexadecimal notation, as defined in Section 4.2.1 of CSS Color Module
Level 3.
4.3. Recurrence Properties
Some events and tasks occur at regular or irregular intervals.
Rather than having to copy the data for every occurrence, there can
be a base event with rules to generate recurrences and/or overrides
that add extra dates or exceptions to the rules.
The recurrence set is the complete set of instances for an object.
It is generated by considering the following properties in order, all
of which are optional:
1. The "recurrenceRules" property (Section 4.3.3) generates a set of
extra date-times on which the object occurs.
2. The "excludedRecurrenceRules" property (Section 4.3.4) generates
a set of date-times that are to be removed from the previously
generated set of date-times on which the object occurs.
3. The "recurrenceOverrides" property (Section 4.3.5) defines date-
times that are added or excluded to form the final set. (This
property may also contain changes to the object to apply to
particular instances.)
4.3.1. recurrenceId
Type: "LocalDateTime" (optional)
If present, this JSCalendar object represents one occurrence of a
recurring JSCalendar object. If present, the "recurrenceRules" and
"recurrenceOverrides" properties MUST NOT be present.
The value is a date-time either produced by the "recurrenceRules" of
the base event or added as a key to the "recurrenceOverrides"
property of the base event.
4.3.2. recurrenceIdTimeZone
Type: "TimeZoneId|null" (optional, default: null)
Identifies the time zone of the main JSCalendar object, of which this
JSCalendar object is a recurrence instance. It MUST NOT be set if the
"recurrenceId" property is not set.
EID 6873 (Verified) is as follows:Section: 4.3.2.
Original Text:
Identifies the time zone of the main JSCalendar object, of which this
JSCalendar object is a recurrence instance. This property MUST be
set if the "recurrenceId" property is set. It MUST NOT be set if the
"recurrenceId" property is not set.
Corrected Text:
Identifies the time zone of the main JSCalendar object, of which this
JSCalendar object is a recurrence instance. It MUST NOT be set if the
"recurrenceId" property is not set.
Notes:
A recurrence instance may be in floating time, in which case the value of the "recurrenceIdTimeZone" property is null. As null is the default value of the "recurrenceIdTimeZone" property, it is NOT required to be set if "recurrenceId" is set.
4.3.3. recurrenceRules
Type: "RecurrenceRule[]" (optional)
This defines a set of recurrence rules (repeating patterns) for
recurring calendar objects.
An Event recurs by applying the recurrence rules to the "start" date-
time.
A Task recurs by applying the recurrence rules to the "start" date-
time, if defined; otherwise, it recurs by the "due" date-time, if
defined. If the task defines neither a "start" nor "due" date-time,
it MUST NOT define a "recurrenceRules" property.
If multiple recurrence rules are given, each rule is to be applied,
and then the union of the results are used, ignoring any duplicates.
A RecurrenceRule object is a JSON object mapping of a RECUR value
type in iCalendar [RFC5545] [RFC7529] and has the same semantics. It
has the following properties:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be
"RecurrenceRule".
frequency: "String" (mandatory)
This is the time span covered by each iteration of this recurrence
rule (see Section 4.3.3.1 for full semantics). This MUST be one
of the following values:
* "yearly"
* "monthly"
* "weekly"
* "daily"
* "hourly"
* "minutely"
* "secondly"
This is the FREQ part from iCalendar, converted to lowercase.
interval: "UnsignedInt" (optional, default: 1)
This is the interval of iteration periods at which the recurrence
repeats. If included, it MUST be an integer >= 1.
This is the INTERVAL part from iCalendar.
rscale: "String" (optional, default: "gregorian")
This is the calendar system in which this recurrence rule
operates, in lowercase. This MUST be either a CLDR-registered
calendar system name [CLDR] or a vendor-specific value (see
Section 3.3).
This is the RSCALE part from iCalendar RSCALE [RFC7529], converted
to lowercase.
skip: "String" (optional, default: "omit")
This is the behavior to use when the expansion of the recurrence
produces invalid dates. This property only has an effect if the
frequency is "yearly" or "monthly". It MUST be one of the
following values:
* "omit"
* "backward"
* "forward"
This is the SKIP part from iCalendar RSCALE [RFC7529], converted
to lowercase.
firstDayOfWeek: "String" (optional, default: "mo")
This is the day on which the week is considered to start,
represented as a lowercase, abbreviated, and two-letter English
day of the week. If included, it MUST be one of the following
values:
* "mo"
* "tu"
* "we"
* "th"
* "fr"
* "sa"
* "su"
This is the WKST part from iCalendar.
byDay: "NDay[]" (optional)
These are days of the week on which to repeat. An "NDay" object
has the following properties:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be "NDay".
day: "String" (mandatory)
This is a day of the week on which to repeat; the allowed
values are the same as for the "firstDayOfWeek" recurrenceRule
property.
This is the day of the week of the BYDAY part in iCalendar,
converted to lowercase.
nthOfPeriod: "Int" (optional)
If present, rather than representing every occurrence of the
weekday defined in the "day" property, it represents only a
specific instance within the recurrence period. The value can
be positive or negative but MUST NOT be zero. A negative
integer means the nth-last occurrence within that period (i.e.,
-1 is the last occurrence, -2 the one before that, etc.).
This is the ordinal part of the BYDAY value in iCalendar (e.g.,
1 or -3).
byMonthDay: "Int[]" (optional)
These are the days of the month on which to repeat. Valid values
are between 1 and the maximum number of days any month may have in
the calendar given by the "rscale" property and the negative
values of these numbers. For example, in the Gregorian calendar,
valid values are 1 to 31 and -31 to -1. Negative values offset
from the end of the month. The array MUST have at least one entry
if included.
This is the BYMONTHDAY part in iCalendar.
byMonth: "String[]" (optional)
These are the months in which to repeat. Each entry is a string
representation of a number, starting from "1" for the first month
in the calendar (e.g., "1" means January with the Gregorian
calendar), with an optional "L" suffix (see [RFC7529]) for leap
months (this MUST be uppercase, e.g., "3L"). The array MUST have
at least one entry if included.
This is the BYMONTH part from iCalendar.
byYearDay: "Int[]" (optional)
These are the days of the year on which to repeat. Valid values
are between 1 and the maximum number of days any year may have in
the calendar given by the "rscale" property and the negative
values of these numbers. For example, in the Gregorian calendar,
valid values are 1 to 366 and -366 to -1. Negative values offset
from the end of the year. The array MUST have at least one entry
if included.
This is the BYYEARDAY part from iCalendar.
byWeekNo: "Int[]" (optional)
These are the weeks of the year in which to repeat. Valid values
are between 1 and the maximum number of weeks any year may have in
the calendar given by the "rscale" property and the negative
values of these numbers. For example, in the Gregorian calendar,
valid values are 1 to 53 and -53 to -1. The array MUST have at
least one entry if included.
This is the BYWEEKNO part from iCalendar.
byHour: "UnsignedInt[]" (optional)
These are the hours of the day in which to repeat. Valid values
are 0 to 23. The array MUST have at least one entry if included.
This is the BYHOUR part from iCalendar.
byMinute: "UnsignedInt[]" (optional)
These are the minutes of the hour in which to repeat. Valid
values are 0 to 59. The array MUST have at least one entry if
included.
This is the BYMINUTE part from iCalendar.
bySecond: "UnsignedInt[]" (optional)
These are the seconds of the minute in which to repeat. Valid
values are 0 to 60. The array MUST have at least one entry if
included.
This is the BYSECOND part from iCalendar.
bySetPosition: "Int[]" (optional)
These are the occurrences within the recurrence interval to
include in the final results. Negative values offset from the end
of the list of occurrences. The array MUST have at least one
entry if included. This is the BYSETPOS part from iCalendar.
count: "UnsignedInt" (optional)
These are the number of occurrences at which to range-bound the
recurrence. This MUST NOT be included if an "until" property is
specified.
This is the COUNT part from iCalendar.
until: "LocalDateTime" (optional)
These are the date-time at which to finish recurring. The last
occurrence is on or before this date-time. This MUST NOT be
included if a "count" property is specified. Note that if not
specified otherwise for a specific JSCalendar object, this date is
to be interpreted in the time zone specified in the JSCalendar
object's "timeZone" property.
This is the UNTIL part from iCalendar.
4.3.3.1. Interpreting Recurrence Rules
A recurrence rule specifies a set of date-times for recurring
calendar objects. A recurrence rule has the following semantics.
Note that wherever "year", "month", or "day of month" is used, this
is within the calendar system given by the "rscale" property, which
defaults to "gregorian" if omitted.
1. A set of candidates is generated. This is every second within a
period defined by the "frequency" property value:
"yearly": every second from midnight on the first day of a year
(inclusive) to midnight the first day of the following year
(exclusive).
If skip is not "omit", the calendar system has leap months,
and there is a "byMonth" property, generate candidates for the
leap months, even if they don't occur in this year.
If skip is not "omit" and there is a "byMonthDay" property,
presume each month has the maximum number of days any month
may have in this calendar system when generating candidates,
even if it's more than this month actually has.
"monthly": every second from midnight on the first day of a
month (inclusive) to midnight on the first of the following
month (exclusive).
If skip is not "omit" and there is a "byMonthDay" property,
presume the month has the maximum number of days any month may
have in this calendar system when generating candidates, even
if it's more than this month actually has.
"weekly": every second from midnight (inclusive) on the first
day of the week (as defined by the "firstDayOfWeek" property
or Monday if omitted) to midnight seven days later
(exclusive).
"daily": every second from midnight at the start of the day
(inclusive) to midnight at the end of the day (exclusive).
"hourly": every second from the beginning of the hour
(inclusive) to the beginning of the next hour (exclusive).
"minutely": every second from the beginning of the minute
(inclusive) to the beginning of the next minute (exclusive).
"secondly": only the second itself.
2. Each date-time candidate is compared against all of the byX
properties of the rule except bySetPosition. If any property in
the rule does not match the date-time, the date-time is
eliminated. Each byX property is an array; the date-time matches
the property if it matches any of the values in the array. The
properties have the following semantics:
byMonth: The date-time is in the given month.
byWeekNo: The date-time is in the nth week of the year.
Negative numbers mean the nth last week of the year. This
corresponds to weeks according to week numbering, as defined
in ISO.8601.2004, with a week defined as a seven-day period,
starting on the "firstDayOfWeek" property value or Monday if
omitted. Week number one of the calendar year is the first
week that contains at least four days in that calendar year.
If the date-time is not valid (this may happen when generating
candidates with a "skip" property in effect), it is always
eliminated by this property.
byYearDay: The date-time is on the nth day of year. Negative
numbers mean the nth last day of the year.
If the date-time is not valid (this may happen when generating
candidates with a "skip" property in effect), it is always
eliminated by this property.
byMonthDay: The date-time is on the given day of the month.
Negative numbers mean the nth last day of the month.
byDay: The date-time is on the given day of the week. If the
day is prefixed by a number, it is the nth occurrence of that
day of the week within the month (if frequency is monthly) or
year (if frequency is yearly). Negative numbers mean the nth
last occurrence within that period.
byHour: The date-time has the given hour value.
byMinute: The date-time has the given minute value.
bySecond: The date-time has the given second value.
If a "skip" property is defined and is not "omit", there may be
candidates that do not correspond to valid dates (e.g., February
31st in the Gregorian calendar). In this case, the properties
MUST be considered in the order above, and:
1. After applying the byMonth filter, if the candidate's month
is invalid for the given year, increment it (if skip is
"forward") or decrement it (if skip is "backward") until a
valid month is found, incrementing/decrementing the year as
well if passing through the beginning/end of the year. This
only applies to calendar systems with leap months.
2. After applying the byMonthDay filter, if the day of the month
is invalid for the given month and year, change the date to
the first day of the next month (if skip is "forward") or the
last day of the current month (if skip is "backward").
3. If any valid date produced after applying the skip is already
a candidate, eliminate the duplicate. (For example, after
adjusting, February 30th and February 31st would both become
the same "real" date, so one is eliminated as a duplicate.)
3. If a "bySetPosition" property is included, this is now applied to
the ordered list of remaining dates. This property specifies the
indexes of date-times to keep; all others should be eliminated.
Negative numbers are indexed from the end of the list, with -1
being the last item, -2 the second from last, etc.
4. Any date-times before the start date of the event are eliminated
(see below for why this might be needed).
5. If a "skip" property is included and is not "omit", eliminate any
date-times that have already been produced by previous iterations
of the algorithm. (This is not possible if skip is "omit".)
6. If further dates are required (we have not reached the until date
or count limit), skip the next (interval - 1) sets of candidates,
then continue from step 1.
When determining the set of occurrence dates for an event or task,
the following extra rules must be applied:
1. The initial date-time to which the rule is applied (the "start"
date-time for events or the "start" or "due" date-time for tasks)
is always the first occurrence in the expansion (and is counted
if the recurrence is limited by a "count" property), even if it
would normally not match the rule.
2. The first set of candidates to consider is that which would
contain the initial date-time. This means the first set may
include candidates before the initial date-time; such candidates
are eliminated from the results in step 4 of the list above.
3. The following properties MUST be implicitly added to the rule
under the given conditions:
* If frequency is not "secondly" and there is no "bySecond"
property, add a "bySecond" property with the sole value being
the seconds value of the initial date-time.
* If frequency is not "secondly" or "minutely" and there is no
"byMinute" property, add a "byMinute" property with the sole
value being the minutes value of the initial date-time.
* If frequency is not "secondly", "minutely", or "hourly" and
there is no "byHour" property, add a "byHour" property with
the sole value being the hours value of the initial date-time.
* If frequency is "weekly" and there is no "byDay" property, add
a "byDay" property with the sole value being the day of the
week of the initial date-time.
* If frequency is "monthly" and there is no "byDay" property and
no "byMonthDay" property, add a "byMonthDay" property with the
sole value being the day of the month of the initial date-
time.
* If frequency is "yearly" and there is no "byYearDay" property:
- If there are no "byMonth" or "byWeekNo" properties, and
either there is a "byMonthDay" property or there is no
"byDay" property, add a "byMonth" property with the sole
value being the month of the initial date-time.
- If there are no "byMonthDay", "byWeekNo", or "byDay"
properties, add a "byMonthDay" property with the sole value
being the day of the month of the initial date-time.
- If there is a "byWeekNo" property and no "byMonthDay" or
"byDay" properties, add a "byDay" property with the sole
value being the day of the week of the initial date-time.
4.3.4. excludedRecurrenceRules
Type: "RecurrenceRule[]" (optional)
This defines a set of recurrence rules (repeating patterns) for date-
times on which the object will not occur. The rules are interpreted
the same as for the "recurrenceRules" property (see Section 4.3.3),
with the exception that the initial date-time to which the rule is
applied (the "start" date-time for events or the "start" or "due"
date-time for tasks) is only considered part of the expansion if it
matches the rule. The resulting set of date-times is then removed
from those generated by the "recurrenceRules" property, as described
in Section 4.3.
4.3.5. recurrenceOverrides
Type: "LocalDateTime[PatchObject]" (optional)
Maps recurrence ids (the date-time produced by the recurrence rule)
to the overridden properties of the recurrence instance.
If the recurrence id does not match a date-time from the recurrence
rule (or no rule is specified), it is to be treated as an additional
occurrence (like an RDATE from iCalendar). The patch object may
often be empty in this case.
If the patch object defines the "excluded" property of an occurrence
to be true, this occurrence is omitted from the final set of
recurrences for the calendar object (like an EXDATE from iCalendar).
Such a patch object MUST NOT patch any other property.
By default, an occurrence inherits all properties from the main
object except the start (or due) date-time, which is shifted to match
the recurrence id LocalDateTime. However, individual properties of
the occurrence can be modified by a patch or multiple patches. It is
valid to patch the "start" property value, and this patch takes
precedence over the value generated from the recurrence id. Both the
recurrence id as well as the patched "start" date-time may occur
before the original JSCalendar object's "start" or "due" date.
A pointer in the PatchObject MUST be ignored if it starts with one of
the following prefixes:
* @type
* excludedRecurrenceRules
* method
* privacy
* prodId
* recurrenceId
* recurrenceIdTimeZone
* recurrenceOverrides
* recurrenceRules
* relatedTo
* replyTo
* sentBy
* timeZones
* uid
4.3.6. excluded
Type: "Boolean" (optional, default: false)
This defines if this object is an overridden, excluded instance of a
recurring JSCalendar object (see Section 4.3.5). If this property
value is true, this calendar object instance MUST be removed from the
occurrence expansion. The absence of this property, or the presence
of its default value as false, indicates that this instance MUST be
included in the occurrence expansion.
4.4. Sharing and Scheduling Properties
4.4.1. priority
Type: "Int" (optional, default: 0)
This specifies a priority for the calendar object. This may be used
as part of scheduling systems to help resolve conflicts for a time
period.
The priority is specified as an integer in the range 0 to 9. A value
of 0 specifies an undefined priority, for which the treatment will
vary by situation. A value of 1 is the highest priority. A value of
2 is the second highest priority. Subsequent numbers specify a
decreasing ordinal priority. A value of 9 is the lowest priority.
Other integer values are reserved for future use.
4.4.2. freeBusyStatus
Type: "String" (optional, default: "busy")
This specifies how this calendar object should be treated when
calculating free-busy state. This MUST be one of the following
values, another value registered in the IANA "JSCalendar Enum Values"
registry, or a vendor-specific value (see Section 3.3):
"free": The object should be ignored when calculating whether the
user is busy.
"busy": The object should be included when calculating whether the
user is busy.
4.4.3. privacy
Type: "String" (optional, default: "public")
Calendar objects are normally collected together and may be shared
with other users. The privacy property allows the object owner to
indicate that it should not be shared or should only have the time
information shared but the details withheld. Enforcement of the
restrictions indicated by this property is up to the API via which
this object is accessed.
This property MUST NOT affect the information sent to scheduled
participants; it is only interpreted by protocols that share the
calendar objects belonging to one user with other users.
The value MUST be one of the following values, another value
registered in the IANA "JSCalendar Enum Values" registry, or a
vendor-specific value (see Section 3.3). Any value the client or
server doesn't understand should be preserved but treated as
equivalent to "private".
"public": The full details of the object are visible to those whom
the object's calendar is shared with.
"private": The details of the object are hidden; only the basic time
and metadata are shared. The following properties MAY be shared;
any other properties MUST NOT be shared:
* @type
* created
* due
* duration
* estimatedDuration
* excluded
* excludedRecurrenceRules
* freeBusyStatus
* privacy
* recurrenceId
* recurrenceIdTimeZone
* recurrenceOverrides (Only patches that apply to another
permissible property are allowed to be shared.)
* recurrenceRules
* sequence
* showWithoutTime
* start
* timeZone
* timeZones
* uid
* updated
EID 6872 (Verified) is as follows:Section: 4.4.3.
Original Text:
"private": The details of the object are hidden; only the basic time
and metadata are shared. The following properties MAY be shared;
any other properties MUST NOT be shared:
* @type
* created
* due
* duration
* estimatedDuration
* freeBusyStatus
* privacy
* recurrenceOverrides (Only patches that apply to another
permissible property are allowed to be shared.)
* sequence
* showWithoutTime
* start
* timeZone
* timeZones
* uid
* updated
Corrected Text:
"private": The details of the object are hidden; only the basic time
and metadata are shared. The following properties MAY be shared;
any other properties MUST NOT be shared:
* @type
* created
* due
* duration
* estimatedDuration
* excluded
* excludedRecurrenceRules
* freeBusyStatus
* privacy
* recurrenceId
* recurrenceIdTimeZone
* recurrenceOverrides (Only patches that apply to another
permissible property are allowed to be shared.)
* recurrenceRules
* sequence
* showWithoutTime
* start
* timeZone
* timeZones
* uid
* updated
Notes:
Adds the excluded, excludedRecurrenceRules, recurrenceId, recurrenceIdTimeZone and recurrenceRules properties to the list of shared properties of private events.
Only the combination of all recurrence properties allows to generate the full recurrence set for the event.
Omitting the properties was an oversight during the initial publication of this RFC.
"secret": The object is hidden completely (as though it did not
exist) when the calendar this object is in is shared.
4.4.4. replyTo
Type: "String[String]" (optional)
This represents methods by which participants may submit their
response to the organizer of the calendar object. The keys in the
property value are the available methods and MUST only contain ASCII
alphanumeric characters (A-Za-z0-9). The value is a URI for the
method specified in the key. Future methods may be defined in future
specifications and registered with IANA; a calendar client MUST
ignore any method it does not understand but MUST preserve the method
key and URI. This property MUST be omitted if no method is defined
(rather than being specified as an empty object).
The following methods are defined:
"imip": The organizer accepts an iCalendar Message-Based
Interoperability Protocol (iMIP) [RFC6047] response at this email
address. The value MUST be a "mailto:" URI.
"web": Opening this URI in a web browser will provide the user with
a page where they can submit a reply to the organizer. The value
MUST be a URL using the "https:" scheme.
"other": The organizer is identified by this URI, but the method for
submitting the response is undefined.
4.4.5. sentBy
Type: "String" (optional)
This is the email address in the "From" header of the email in which
this calendar object was received. This is only relevant if the
calendar object is received via iMIP or as an attachment to a
message. If set, the value MUST be a valid "addr-spec" value as
defined in Section 3.4.1 of [RFC5322].
4.4.6. participants
Type: "Id[Participant]" (optional)
This is a map of participant ids to participants, describing their
participation in the calendar object.
If this property is set and any participant has a "sendTo" property,
then the "replyTo" property of this calendar object MUST define at
least one reply method.
A Participant object has the following properties:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be
"Participant".
name: "String" (optional)
This is the display name of the participant (e.g., "Joe Bloggs").
email: "String" (optional)
This is the email address to use to contact the participant or,
for example, match with an address book entry. If set, the value
MUST be a valid "addr-spec" value as defined in Section 3.4.1 of
[RFC5322].
description: "String" (optional)
This is a plain-text description of this participant. For
example, this may include more information about their role in the
event or how best to contact them.
sendTo: "String[String]" (optional)
This represents methods by which the participant may receive the
invitation and updates to the calendar object.
The keys in the property value are the available methods and MUST
only contain ASCII alphanumeric characters (A-Za-z0-9). The value
is a URI for the method specified in the key. Future methods may
be defined in future specifications and registered with IANA; a
calendar client MUST ignore any method it does not understand but
MUST preserve the method key and URI. This property MUST be
omitted if no method is defined (rather than being specified as an
empty object).
The following methods are defined:
"imip": The participant accepts an iMIP [RFC6047] request at this
email address. The value MUST be a "mailto:" URI. It MAY be
different from the value of the participant's "email" property.
"other": The participant is identified by this URI, but the
method for submitting the invitation is undefined.
kind: "String" (optional)
This is what kind of entity this participant is, if known.
This MUST be one of the following values, another value registered
in the IANA "JSCalendar Enum Values" registry, or a vendor-
specific value (see Section 3.3). Any value the client or server
doesn't understand should be treated the same as if this property
is omitted.
"individual": a single person
"group": a collection of people invited as a whole
"location": a physical location that needs to be scheduled, e.g.,
a conference room
"resource": a non-human resource other than a location, such as a
projector
roles: "String[Boolean]" (mandatory)
This is a set of roles that this participant fulfills.
At least one role MUST be specified for the participant. The keys
in the set MUST be one of the following values, another value
registered in the IANA "JSCalendar Enum Values" registry, or a
vendor-specific value (see Section 3.3):
"owner": The participant is an owner of the object. This
signifies they have permission to make changes to it that
affect the other participants. Nonowner participants may only
change properties that affect only themselves (for example,
setting their own alerts or changing their RSVP status).
"attendee": The participant is expected to be present at the
event.
"optional": The participant's involvement with the event is
optional. This is expected to be primarily combined with the
"attendee" role.
"informational": The participant is copied for informational
reasons and is not expected to attend.
"chair": The participant is in charge of the event/task when it
occurs.
"contact": The participant is someone that may be contacted for
information about the event.
The value for each key in the map MUST be true. It is expected
that no more than one of the roles "attendee" and "informational"
be present; if more than one are given, "attendee" takes
precedence over "informational". Roles that are unknown to the
implementation MUST be preserved.
locationId: "Id" (optional)
This is the location at which this participant is expected to be
attending.
If the value does not correspond to any location id in the
"locations" property of the JSCalendar object, this MUST be
treated the same as if the participant's locationId were omitted.
language: "String" (optional)
This is the language tag, as defined in [RFC5646], that best
describes the participant's preferred language, if known.
participationStatus: "String" (optional, default: "needs-action")
This is the participation status, if any, of this participant.
The value MUST be one of the following values, another value
registered in the IANA "JSCalendar Enum Values" registry, or a
vendor-specific value (see Section 3.3):
"needs-action": No status has yet been set by the participant.
"accepted": The invited participant will participate.
"declined": The invited participant will not participate.
"tentative": The invited participant may participate.
"delegated": The invited participant has delegated their
attendance to another participant, as specified in the
"delegatedTo" property.
participationComment: "String" (optional)
This is a note from the participant to explain their participation
status.
expectReply: "Boolean" (optional, default: false)
If true, the organizer is expecting the participant to notify them
of their participation status.
scheduleAgent: "String" (optional, default: "server")
This is who is responsible for sending scheduling messages with
this calendar object to the participant.
The value MUST be one of the following values, another value
registered in the IANA "JSCalendar Enum Values" registry, or a
vendor-specific value (see Section 3.3):
"server": The calendar server will send the scheduling messages.
"client": The calendar client will send the scheduling messages.
"none": No scheduling messages are to be sent to this
participant.
scheduleForceSend: "Boolean" (optional, default: false)
A client may set the property on a participant to true to request
that the server send a scheduling message to the participant when
it would not normally do so (e.g., if no significant change is
made the object or the scheduleAgent is set to client). The
property MUST NOT be stored in the JSCalendar object on the server
or appear in a scheduling message.
scheduleSequence: "UnsignedInt" (optional, default: 0)
This is the sequence number of the last response from the
participant. If defined, this MUST be a nonnegative integer.
This can be used to determine whether the participant has sent a
new response following significant changes to the calendar object
and to determine if future responses are responding to a current
or older view of the data.
scheduleStatus: "String[]" (optional)
This is a list of status codes, returned from the processing of
the most recent scheduling message sent to this participant. The
status codes MUST be valid "statcode" values as defined in the
ABNF in Section 3.8.8.3 of [RFC5545].
Servers MUST only add or change this property when they send a
scheduling message to the participant. Clients SHOULD NOT change
or remove this property if it was provided by the server. Clients
MAY add, change, or remove the property for participants where the
client is handling the scheduling.
This property MUST NOT be included in scheduling messages.
scheduleUpdated: "UTCDateTime" (optional)
This is the timestamp for the most recent response from this
participant.
This is the "updated" property of the last response when using
iTIP. It can be compared to the "updated" property in future
responses to detect and discard older responses delivered out of
order.
sentBy: "String" (optional)
This is the email address in the "From" header of the email that
last updated this participant via iMIP. This SHOULD only be set
if the email address is different to that in the mailto URI of
this participant's "imip" method in the "sendTo" property (i.e.,
the response was received from a different address to that which
the invitation was sent to). If set, the value MUST be a valid
"addr-spec" value as defined in Section 3.4.1 of [RFC5322].
invitedBy: "Id" (optional)
This is the id of the participant who added this participant to
the event/task, if known.
delegatedTo: "Id[Boolean]" (optional)
This is set of participant ids that this participant has delegated
their participation to. Each key in the set MUST be the id of a
participant. The value for each key in the map MUST be true. If
there are no delegates, this MUST be omitted (rather than
specified as an empty set).
delegatedFrom: "Id[Boolean]" (optional)
This is a set of participant ids that this participant is acting
as a delegate for. Each key in the set MUST be the id of a
participant. The value for each key in the map MUST be true. If
there are no delegators, this MUST be omitted (rather than
specified as an empty set).
memberOf: "Id[Boolean]" (optional)
This is a set of group participants that were invited to this
calendar object, which caused this participant to be invited due
to their membership in the group(s). Each key in the set MUST be
the id of a participant. The value for each key in the map MUST
be true. If there are no groups, this MUST be omitted (rather
than specified as an empty set).
links: "Id[Link]" (optional)
This is a map of link ids to Link objects, representing external
resources associated with this participant, for example, a vCard
or image. If there are no links, this MUST be omitted (rather
than specified as an empty set).
progress: "String" (optional; only allowed for participants of a
Task)
This represents the progress of the participant for this task. It
MUST NOT be set if the "participationStatus" of this participant
is any value other than "accepted". See Section 5.2.5 for allowed
values and semantics.
progressUpdated: "UTCDateTime" (optional; only allowed for
participants of a Task)
This specifies the date-time the "progress" property was last set
on this participant. See Section 5.2.6 for allowed values and
semantics.
percentComplete: "UnsignedInt" (optional; only allowed for
participants of a Task)
This represents the percent completion of the participant for this
task. The property value MUST be a positive integer between 0 and
100.
4.4.7. requestStatus
Type: "String" (optional)
A request status as returned from processing the most recent
scheduling request for this JSCalendar object. The allowed values
are defined by the ABNF definitions of "statcode", "statdesc" and
"extdata" in Section 3.8.8.3 of [RFC5545] and the following ABNF
[RFC5234]:
reqstatus = statcode ";" statdesc [";" extdata]
Servers MUST only add or change this property when they performe a
scheduling action. Clients SHOULD NOT change or remove this property
if it was provided by the server. Clients MAY add, change, or remove
the property when the client is handling the scheduling.
This property MUST only be included in scheduling messages according
to the rules defined for the REQUEST-STATUS iCalendar property in
[RFC5546].
4.5. Alerts Properties
4.5.1. useDefaultAlerts
Type: "Boolean" (optional, default: false)
If true, use the user's default alerts and ignore the value of the
"alerts" property. Fetching user defaults is dependent on the API
from which this JSCalendar object is being fetched and is not defined
in this specification. If an implementation cannot determine the
user's default alerts, or none are set, it MUST process the "alerts"
property as if "useDefaultAlerts" is set to false.
4.5.2. alerts
Type: "Id[Alert]" (optional)
This is a map of alert ids to Alert objects, representing alerts/
reminders to display or send to the user for this calendar object.
An Alert object has the following properties:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be "Alert".
trigger: "OffsetTrigger|AbsoluteTrigger|UnknownTrigger"
(mandatory)
This defines when to trigger the alert. New types may be defined
in future documents.
An "OffsetTrigger" object has the following properties:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be
"OffsetTrigger".
offset: "SignedDuration" (mandatory)
This defines the offset at which to trigger the alert relative
to the time property defined in the "relativeTo" property of
the alert. Negative durations signify alerts before the time
property; positive durations signify alerts after the time
property.
relativeTo: "String" (optional, default: "start")
This specifies the time property that the alert offset is
relative to. The value MUST be one of the following:
"start": triggers the alert relative to the start of the
calendar object
"end": triggers the alert relative to the end/due time of the
calendar object
An "AbsoluteTrigger" object has the following properties:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be
"AbsoluteTrigger".
when: "UTCDateTime" (mandatory)
This defines a specific UTC date-time when the alert is
triggered.
An "UnknownTrigger" object is an object that contains an "@type"
property whose value is not recognized (i.e., not "OffsetTrigger"
or "AbsoluteTrigger") plus zero or more other properties. This is
for compatibility with client extensions and future
specifications. Implementations SHOULD NOT trigger for trigger
types they do not understand but MUST preserve them.
acknowledged: "UTCDateTime" (optional)
This records when an alert was last acknowledged. This is set
when the user has dismissed the alert; other clients that sync
this property SHOULD automatically dismiss or suppress duplicate
alerts (alerts with the same alert id that triggered on or before
this date-time).
For a recurring calendar object, setting the "acknowledged"
property MUST NOT add a new override to the "recurrenceOverrides"
property. If the alert is not already overridden, the
"acknowledged" property MUST be set on the alert in the base
event/task.
Certain kinds of alert action may not provide feedback as to when
the user sees them, for example, email-based alerts. For those
kinds of alerts, this property MUST be set immediately when the
alert is triggered and the action is successfully carried out.
relatedTo: "String[Relation]" (optional)
This relates this alert to other alerts in the same JSCalendar
object. If the user wishes to snooze an alert, the application
MUST create an alert to trigger after snoozing. This new snooze
alert MUST set a parent relation to the identifier of the original
alert.
action: "String" (optional, default: "display")
This describes how to alert the user.
The value MUST be at most one of the following values, a value
registered in the IANA "JSCalendar Enum Values" registry, or a
vendor-specific value (see Section 3.3):
"display": The alert should be displayed as appropriate for the
current device and user context.
"email": The alert should trigger an email sent out to the user,
notifying them of the alert. This action is typically only
appropriate for server implementations.
4.6. Multilingual Properties
4.6.1. localizations
Type: "String[PatchObject]" (optional)
A map where each key is a language tag [RFC5646], and the
corresponding value is a set of patches to apply to the calendar
object in order to localize it into that locale.
See the description of PatchObject (Section 1.4.9) for the structure
of the PatchObject. The patches are applied to the top-level
calendar object. In addition, the "locale" property of the patched
object is set to the language tag. All pointers for patches MUST end
with one of the following suffixes; any patch that does not follow
this MUST be ignored unless otherwise specified in a future RFC:
* title
* description
* name
A patch MUST NOT have the prefix "recurrenceOverrides"; any
localization of the override MUST be a patch to the "localizations"
property inside the override instead. For example, a patch to
"locations/abcd1234/title" is permissible, but a patch to "uid" or
"recurrenceOverrides/2020-01-05T14:00:00/title" is not.
Note that this specification does not define how to maintain validity
of localized content. For example, a client application changing a
JSCalendar object's "title" property might also need to update any
localizations of this property. Client implementations SHOULD
provide the means to manage localizations, but how to achieve this is
specific to the application's workflow and requirements.
4.7. Time Zone Properties
4.7.1. timeZone
Type: "TimeZoneId|null" (optional, default: null)
This identifies the time zone the object is scheduled in or is null
for floating time. This is either a name from the IANA Time Zone
Database [TZDB] or the TimeZoneId of a custom time zone from the
"timeZones" property (Section 4.7.2). If omitted, this MUST be
presumed to be null (i.e., floating time).
4.7.2. timeZones
Type: "TimeZoneId[TimeZone]" (optional)
This maps identifiers of custom time zones to their time zone
definitions. The following restrictions apply for each key in the
map:
* To avoid conflict with names in the IANA Time Zone Database
[TZDB], it MUST start with the "/" character.
* It MUST be a valid "paramtext" value, as specified in Section 3.1
of [RFC5545].
* At least one other property in the same JSCalendar object MUST
reference a time zone using this identifier (i.e., orphaned time
zones are not allowed).
An identifier need only be unique to this JSCalendar object. It MAY
differ from the "tzId" property value of the TimeZone object it maps
to.
A JSCalendar object may be part of a hierarchy of other JSCalendar
objects (say, an Event is an entry in a Group). In this case, the
set of time zones is the sum of the time zone definitions of this
object and its parent objects. If multiple time zones with the same
identifier exist, then the definition closest to the calendar object
in relation to its parents MUST be used. (In context of Event, a
time zone definition in its "timeZones" property has precedence over
a definition of the same id in the Group). Time zone definitions in
any children of the calendar object MUST be ignored.
A TimeZone object maps a VTIMEZONE component from iCalendar, and the
semantics are as defined in [RFC5545]. A valid time zone MUST define
at least one transition rule in the "standard" or "daylight"
property. Its properties are:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be "TimeZone".
tzId: "String" (mandatory)
This is the TZID property from iCalendar. Note that this implies
that the value MUST be a valid "paramtext" value as specified in
Section 3.1. of [RFC5545].
updated: "UTCDateTime" (optional)
This is the LAST-MODIFIED property from iCalendar.
url: "String" (optional)
This is the TZURL property from iCalendar.
validUntil: "UTCDateTime" (optional)
This is the TZUNTIL property from iCalendar, specified in
[RFC7808].
aliases: "String[Boolean]" (optional)
This maps the TZID-ALIAS-OF properties from iCalendar, specified
in [RFC7808], to a JSON set of aliases. The set is represented as
an object, with the keys being the aliases. The value for each
key in the map MUST be true.
standard: "TimeZoneRule[]" (optional)
This the STANDARD sub-components from iCalendar. The order MUST
be preserved during conversion.
daylight: "TimeZoneRule[]" (optional)
This the DAYLIGHT sub-components from iCalendar. The order MUST
be preserved during conversion.
A TimeZoneRule object maps a STANDARD or DAYLIGHT sub-component from
iCalendar, with the restriction that, at most, one recurrence rule is
allowed per rule. It has the following properties:
@type: "String" (mandatory)
This specifies the type of this object. This MUST be
"TimeZoneRule".
start: "LocalDateTime" (mandatory)
This is the DTSTART property from iCalendar.
offsetFrom: "String" (mandatory)
This is the TZOFFSETFROM property from iCalendar.
offsetTo: "String" (mandatory)
This is the TZOFFSETTO property from iCalendar.
recurrenceRules: "RecurrenceRule[]" (optional)
This is the RRULE property mapped, as specified in Section 4.3.3.
During recurrence rule evaluation, the "until" property value MUST
be interpreted as a local time in the UTC time zone.
recurrenceOverrides: "LocalDateTime[PatchObject]" (optional)
This maps the RDATE properties from iCalendar. The set is
represented as an object, with the keys being the recurrence
dates. The patch object MUST be the empty JSON object ({}).
names: "String[Boolean]" optional)
This maps the TZNAME properties from iCalendar to a JSON set. The
set is represented as an object, with the keys being the names,
excluding any "tznparam" component from iCalendar. The value for
each key in the map MUST be true.
comments: "String[]" (optional)
This maps the COMMENT properties from iCalendar. The order MUST
be preserved during conversion.
5. Type-Specific JSCalendar Properties
5.1. Event Properties
In addition to the common JSCalendar object properties (Section 4),
an Event has the following properties:
5.1.1. start
Type: "LocalDateTime" (mandatory)
This is the date/time the event starts in the event's time zone (as
specified in the "timeZone" property, see Section 4.7.1).
5.1.2. duration
Type: "Duration" (optional, default: "PT0S")
This is the zero or positive duration of the event in the event's
start time zone. The end time of an event can be found by adding the
duration to the event's start time.
An Event MAY involve start and end locations that are in different
time zones (e.g., a transcontinental flight). This can be expressed
using the "relativeTo" and "timeZone" properties of the Event's
Location objects (see Section 4.2.5).
5.1.3. status
Type: "String" (optional, default: "confirmed")
This is the scheduling status (Section 4.4) of an Event. If set, it
MUST be one of the following values, another value registered in the
IANA "JSCalendar Enum Values" registry, or a vendor-specific value
(see Section 3.3):
"confirmed": indicates the event is definitely happening
"cancelled": indicates the event has been cancelled
"tentative": indicates the event may happen
5.2. Task Properties
In addition to the common JSCalendar object properties (Section 4), a
Task has the following properties:
5.2.1. due
Type: "LocalDateTime" (optional)
This is the date/time the task is due in the task's time zone.
5.2.2. start
Type: "LocalDateTime" (optional)
This the date/time the task should start in the task's time zone.
5.2.3. estimatedDuration
Type: "Duration" (optional)
This specifies the estimated positive duration of time the task takes
to complete.
5.2.4. percentComplete
Type: "UnsignedInt" (optional)
This represents the percent completion of the task overall. The
property value MUST be a positive integer between 0 and 100.
5.2.5. progress
Type: "String" (optional)
This defines the progress of this task. If omitted, the default
progress (Section 4.4) of a Task is defined as follows (in order of
evaluation):
"completed": if the "progress" property value of all participants is
"completed"
"failed": if at least one "progress" property value of a participant
is "failed"
"in-process": if at least one "progress" property value of a
participant is "in-process"
"needs-action": if none of the other criteria match
If set, it MUST be one of the following values, another value
registered in the IANA "JSCalendar Enum Values" registry, or a
vendor-specific value (see Section 3.3):
"needs-action": indicates the task needs action
"in-process": indicates the task is in process
"completed": indicates the task is completed
"failed": indicates the task failed
"cancelled": indicates the task was cancelled
5.2.6. progressUpdated
Type: "UTCDateTime" (optional)
This specifies the date/time the "progress" property of either the
task overall (Section 5.2.5) or a specific participant
(Section 4.4.6) was last updated.
If the task is recurring and has future instances, a client may want
to keep track of the last progress update timestamp of a specific
task recurrence but leave other instances unchanged. One way to
achieve this is by overriding the "progressUpdated" property in the
task "recurrenceOverrides" property. However, this could produce a
long list of timestamps for regularly recurring tasks. An
alternative approach is to split the Task into a current, single
instance of Task with this instance progress update time and a future
recurring instance. See also Section 4.1.3 on splitting.
5.3. Group Properties
Group supports the following common JSCalendar properties
(Section 4):
* @type
* uid
* prodId
* created
* updated
* title
* description
* descriptionContentType
* links
* locale
* keywords
* categories
* color
* timeZones
In addition, the following Group-specific properties are supported:
5.3.1. entries
Type: "(Task|Event)[]" (mandatory)
This is a collection of group members. Implementations MUST ignore
entries of unknown type.
5.3.2. source
Type: "String" (optional)
This is the source from which updated versions of this group may be
retrieved. The value MUST be a URI.
6. Examples
The following examples illustrate several aspects of the JSCalendar
data model and format. The examples may omit mandatory or additional
properties, which is indicated by a placeholder property with key
"...". While most of the examples use calendar event objects, they
are also illustrative for tasks.
6.1. Simple Event
This example illustrates a simple one-time event. It specifies a
one-time event that begins on January 15, 2020 at 1 pm New York local
time and ends after 1 hour.
{
"@type": "Event",
"uid": "a8df6573-0474-496d-8496-033ad45d7fea",
"updated": "2020-01-02T18:23:04Z",
"title": "Some event",
"start": "2020-01-15T13:00:00",
"timeZone": "America/New_York",
"duration": "PT1H"
}
6.2. Simple Task
This example illustrates a simple task for a plain to-do item.
{
"@type": "Task",
"uid": "2a358cee-6489-4f14-a57f-c104db4dc2f2",
"updated": "2020-01-09T14:32:01Z",
"title": "Do something"
}
6.3. Simple Group
This example illustrates a simple calendar object group that contains
an event and a task.
{
"@type": "Group",
"uid": "bf0ac22b-4989-4caf-9ebd-54301b4ee51a",
"updated": "2020-01-15T18:00:00Z",
"name": "A simple group",
"entries": [{
"@type": "Event",
"uid": "a8df6573-0474-496d-8496-033ad45d7fea",
"updated": "2020-01-02T18:23:04Z",
"title": "Some event",
"start": "2020-01-15T13:00:00",
"timeZone": "America/New_York",
"duration": "PT1H"
},
{
"@type": "Task",
"uid": "2a358cee-6489-4f14-a57f-c104db4dc2f2",
"updated": "2020-01-09T14:32:01Z",
"title": "Do something"
}]
}
6.4. All-Day Event
This example illustrates an event for an international holiday. It
specifies an all-day event on April 1 that occurs every year since
the year 1900.
{
"...": "",
"title": "April Fool's Day",
"showWithoutTime": true,
"start": "1900-04-01T00:00:00",
"duration": "P1D",
"recurrenceRules": [{
"@type": "RecurrenceRule",
"frequency": "yearly"
}]
}
6.5. Task with a Due Date
This example illustrates a task with a due date. It is a reminder to
buy groceries before 6 pm Vienna local time on January 19, 2020. The
calendar user expects to need 1 hour for shopping.
{
"...": "",
"title": "Buy groceries",
"due": "2020-01-19T18:00:00",
"timeZone": "Europe/Vienna",
"estimatedDuration": "PT1H"
}
6.6. Event with End Time Zone
This example illustrates the use of end time zones by use of an
international flight. The flight starts on April 1, 2020 at 9 am in
Berlin local time. The duration of the flight is scheduled at 10
hours 30 minutes. The time at the flight's destination is in the
same time zone as Tokyo. Calendar clients could use the end time
zone to display the arrival time in Tokyo local time and highlight
the time zone difference of the flight. The location names can serve
as input for navigation systems.
{
"...": "",
"title": "Flight XY51 to Tokyo",
"start": "2020-04-01T09:00:00",
"timeZone": "Europe/Berlin",
"duration": "PT10H30M",
"locations": {
"1": {
"@type": "Location",
"rel": "start",
"name": "Frankfurt Airport (FRA)"
},
"2": {
"@type": "Location",
"rel": "end",
"name": "Narita International Airport (NRT)",
"timeZone": "Asia/Tokyo"
}
}
}
6.7. Floating-Time Event (with Recurrence)
This example illustrates the use of floating time. Since January 1,
2020, a calendar user blocks 30 minutes every day to practice yoga at
7 am local time in whatever time zone the user is located on that
date.
{
"...": "",
"title": "Yoga",
"start": "2020-01-01T07:00:00",
"duration": "PT30M",
"recurrenceRules": [{
"@type": "RecurrenceRule",
"frequency": "daily"
}]
}
6.8. Event with Multiple Locations and Localization
This example illustrates an event that happens at both a physical and
a virtual location. Fans can see a live concert on premises or
online. The event title and descriptions are localized.
{
"...": "",
"title": "Live from Music Bowl: The Band",
"description": "Go see the biggest music event ever!",
"locale": "en",
"start": "2020-07-04T17:00:00",
"timeZone": "America/New_York",
"duration": "PT3H",
"locations": {
"c0503d30-8c50-4372-87b5-7657e8e0fedd": {
"@type": "Location",
"name": "The Music Bowl",
"description": "Music Bowl, Central Park, New York",
"coordinates": "geo:40.7829,-73.9654"
}
},
"virtualLocations": {
"vloc1": {
"@type": "VirtualLocation",
"name": "Free live Stream from Music Bowl",
"uri": "https://stream.example.com/the_band_2020"
}
},
"localizations": {
"de": {
"title": "Live von der Music Bowl: The Band!",
"description": "Schau dir das größte Musikereignis an!",
"virtualLocations/vloc1/name":
"Gratis Live-Stream aus der Music Bowl"
}
}
}
6.9. Recurring Event with Overrides
This example illustrates the use of recurrence overrides. A math
course at a university is held for the first time on January 8, 2020
at 9 am London time and occurs every week until June 24, 2020. Each
lecture lasts for one hour and 30 minutes and is located at the
Mathematics department. This event has exceptional occurrences: at
the last occurrence of the course is an exam, which lasts for 2 hours
and starts at 10 am. Also, the location of the exam differs from the
usual location. On April 1, no course is held. On January 7 at 2
pm, there is an optional introduction course, which occurs before the
first regular lecture.
{
"...": "",
"title": "Calculus I",
"start": "2020-01-08T09:00:00",
"timeZone": "Europe/London",
"duration": "PT1H30M",
"locations": {
"mlab": {
"@type": "Location",
"title": "Math lab room 1",
"description": "Math Lab I, Department of Mathematics"
}
},
"recurrenceRules": [{
"@type": "RecurrenceRule",
"frequency": "weekly",
"until": "2020-06-24T09:00:00"
}],
"recurrenceOverrides": {
"2020-01-07T14:00:00": {
"title": "Introduction to Calculus I (optional)"
},
"2020-04-01T09:00:00": {
"excluded": true
},
"2020-06-25T09:00:00": {
"title": "Calculus I Exam",
"start": "2020-06-25T10:00:00",
"duration": "PT2H",
"locations": {
"auditorium": {
"@type": "Location",
"title": "Big Auditorium",
"description": "Big Auditorium, Other Road"
}
}
}
}
}
6.10. Recurring Event with Participants
This example illustrates scheduled events. A team meeting occurs
every week since January 8, 2020 at 9 am Johannesburg time. The
event owner also chairs the event. Participants meet in a virtual
meeting room. An attendee has accepted the invitation, but, on March
4, 2020, he is unavailable and declined participation for this
occurrence.
{
"...": "",
"title": "FooBar team meeting",
"start": "2020-01-08T09:00:00",
"timeZone": "Africa/Johannesburg",
"duration": "PT1H",
"virtualLocations": {
"0": {
"@type": "VirtualLocation",
"name": "ChatMe meeting room",
"uri": "https://chatme.example.com?id=1234567&pw=a8a24627b63d"
}
},
"recurrenceRules": [{
"@type": "RecurrenceRule",
"frequency": "weekly"
}],
"replyTo": {
"imip": "mailto:f245f875-7f63-4a5e-a2c8@schedule.example.com"
},
"participants": {
"dG9tQGZvb2Jhci5xlLmNvbQ": {
"@type": "Participant",
"name": "Tom Tool",
"email": "tom@foobar.example.com",
"sendTo": {
"imip": "mailto:tom@calendar.example.com"
},
"participationStatus": "accepted",
"roles": {
"attendee": true
}
},
"em9lQGZvb2GFtcGxlLmNvbQ": {
"@type": "Participant",
"name": "Zoe Zelda",
"email": "zoe@foobar.example.com",
"sendTo": {
"imip": "mailto:zoe@foobar.example.com"
},
"participationStatus": "accepted",
"roles": {
"owner": true,
"attendee": true,
"chair": true
}
}
},
"recurrenceOverrides": {
"2020-03-04T09:00:00": {
"participants/dG9tQGZvb2Jhci5xlLmNvbQ/participationStatus":
"declined"
}
}
}
7. Security Considerations
Calendaring and scheduling information is very privacy sensitive. It
can reveal the social network of a user, location information of this
user and those in their social network, identity and credentials
information, and patterns of behavior of the user in both the
physical and cyber realm. Additionally, calendar events and tasks
can influence the physical location of a user or their cyber behavior
within a known time window. Its transmission and storage must be
done carefully to protect it from possible threats, such as
eavesdropping, replay, message insertion, deletion, modification, and
on-path attacks.
The data being stored and transmitted may be used in systems with
real-world consequences. For example, a home automation system may
turn an alarm on and off or a coworking space may charge money to the
organizer of an event that books one of their meeting rooms. Such
systems must be careful to authenticate all data they receive to
prevent them from being subverted and ensure the change comes from an
authorized entity.
This document only defines the data format; such considerations are
primarily the concern of the API or method of storage and
transmission of such files.
7.1. Expanding Recurrences
A recurrence rule may produce infinite occurrences of an event.
Implementations MUST handle expansions carefully to prevent
accidental or deliberate resource exhaustion.
Conversely, a recurrence rule may be specified that does not expand
to anything. It is not always possible to tell this through static
analysis of the rule, so implementations MUST be careful to avoid
getting stuck in infinite loops or otherwise exhausting resources
while searching for the next occurrence.
Events recur in the event's time zone. If the user is in a different
time zone, daylight saving transitions may cause an event that
normally occurs at, for example, 9 am to suddenly shift an hour
earlier. This may be used in an attempt to cause a participant to
miss an important meeting. User agents must be careful to translate
date-times correctly between time zones and may wish to call out
unexpected changes in the time of a recurring event.
7.2. JSON Parsing
The security considerations of [RFC8259] apply to the use of JSON as
the data interchange format.
As for any serialization format, parsers need to thoroughly check the
syntax of the supplied data. JSON uses opening and closing tags for
several types and structures, and it is possible that the end of the
supplied data will be reached when scanning for a matching closing
tag; this is an error condition, and implementations need to stop
scanning at the end of the supplied data.
JSON also uses a string encoding with some escape sequences to encode
special characters within a string. Care is needed when processing
these escape sequences to ensure that they are fully formed before
the special processing is triggered, with special care taken when the
escape sequences appear adjacent to other (non-escaped) special
characters or adjacent to the end of data (as in the previous
paragraph).
If parsing JSON into a non-textual structured data format,
implementations may need to allocate storage to hold JSON string
elements. Since JSON does not use explicit string lengths, the risk
of denial of service due to resource exhaustion is small, but
implementations may still wish to place limits on the size of
allocations they are willing to make in any given context, to avoid
untrusted data causing excessive memory allocation.
7.3. URI Values
Several JSCalendar properties contain URIs as values, and processing
these properties requires extra care. Section 7 of [RFC3986]
discusses security risks related to URIs.
Fetching remote resources carries inherent risks. Connections must
only be allowed on well-known ports, using allowed protocols
(generally, just HTTP/HTTPS on their default ports). The URL must be
resolved externally and not allowed to access internal resources.
Connecting to an external source reveals IP (and therefore often
location) information.
A maliciously constructed JSCalendar object may contain a very large
number of URIs. In the case of published calendars with a large
number of subscribers, such objects could be widely distributed.
Implementations should be careful to limit the automatic fetching of
linked resources to reduce the risk of this being an amplification
vector for a denial-of-service attack.
7.4. Spam
Calendar systems may receive JSCalendar files from untrusted sources,
in particular, as attachments to emails. This can be a vector for an
attacker to inject spam into a user's calendar. This may confuse,
annoy, and mislead users or overwhelm their calendar with bogus
events, preventing them from seeing legitimate ones.
Heuristic, statistical, or machine-learning-based filters can be
effective in filtering out spam. Authentication mechanisms, such as
DomainKeys Identified Mail (DKIM) [RFC6376], can help establish the
source of messages and associate the data with existing relationships
(such as an address book contact). However, misclassifications are
always possible and providing a mechanism for users to quickly
correct this is advised.
Confusable unicode characters may be used to trick a user into
trusting a JSCalendar file that appears to come from a known contact
but is actually from a similar-looking source controlled by an
attacker.
7.5. Duplication
It is important for calendar systems to maintain the UID of an event
when updating it to avoid an unexpected duplication of events.
Consumers of the data may not remove the previous version of the
event if it has a different UID. This can lead to a confusing
situation for the user, with many variations of the event and no
indication of which one is correct. Care must be taken by consumers
of the data to remove old events where possible to avoid an
accidental denial-of-service attack due to the volume of data.
7.6. Time Zones
Events recur in a particular time zone. When this differs from the
user's current time zone, it may unexpectedly cause an occurrence to
shift in time for that user due to a daylight savings change in the
event's time zone. A maliciously crafted event could attempt to
confuse users with such an event to ensure a meeting is missed.
8. IANA Considerations
8.1. Media Type Registration
This document defines a media type for use with JSCalendar data
formatted in JSON.
Type name: application
Subtype name: jscalendar+json
Required parameters: type
The "type" parameter conveys the type of the JSCalendar data in
the body part. The allowed parameter values correspond to the
"@type" property of the JSON-formatted JSCalendar object in the
body:
"event": The "@type" property value MUST be "Event".
"task": The "@type" property value MUST be "Task".
"group": The "@type" property value MUST be "Group".
No other parameter values are allowed. The parameter MUST NOT
occur more than once.
Optional parameters: none
Encoding considerations: This is the same as the encoding
considerations of application/json, as specified in Section 11 of
[RFC8259].
Security considerations: See Section 7 of this document.
Interoperability considerations: While JSCalendar is designed to
avoid ambiguities as much as possible, when converting objects
from other calendar formats to/from JSCalendar, it is possible
that differing representations for the same logical data or
ambiguities in interpretation might arise. The semantic
equivalence of two JSCalendar objects may be determined
differently by different applications, for example, where URL
values differ in case between the two objects.
Published specification: RFC 8984
Applications that use this media type: Applications that currently
make use of the text/calendar and application/calendar+json media
types can use this as an alternative. Similarly, applications
that use the application/json media type to transfer calendaring
data can use this to further specify the content.
Fragment identifier considerations: A JSON Pointer fragment
identifier may be used, as defined in [RFC6901], Section 6.
Additional information: Magic number(s): N/A
File extensions(s): N/A
Macintosh file type code(s): N/A
Person & email address to contact for further information:
calsify@ietf.org
Intended usage: COMMON
Restrictions on usage: N/A
Author: See the "Author's Address" section of this document.
Change controller: IETF
8.2. Creation of the "JSCalendar Properties" Registry
IANA has created the "JSCalendar Properties" registry to allow
interoperability of extensions to JSCalendar objects.
This registry follows the Expert Review process ([RFC8126],
Section 4.5). If the "Intended Usage" field is "common", sufficient
documentation is required to enable interoperability. Preliminary
community review for this registry is optional but strongly
encouraged.
A registration can have an intended usage of "common", "reserved", or
"obsolete". IANA will list registrations with a common usage
designation prominently and separately from those with other intended
usage values.
A "reserved" registration reserves a property name without assigning
semantics to avoid name collisions with future extensions or protocol
use.
An "obsolete" registration denotes a property that is no longer
expected to be added by up-to-date systems. A new property has
probably been defined covering the obsolete property's semantics.
The JSCalendar property registration procedure is not a formal
standards process but rather an administrative procedure intended to
allow community comment and check it is coherent without excessive
time delay. It is designed to encourage vendors to document and
register new properties they add for use cases not covered by the
original specification, leading to increased interoperability.
8.2.1. Preliminary Community Review
Notice of a potential new registration SHOULD be sent to the Calext
mailing list <calsify@ietf.org> for review. This mailing list is
appropriate to solicit community feedback on a proposed new property.
Property registrations must be marked with their intended use:
"common", "reserved", or "obsolete".
The intent of the public posting to this list is to solicit comments
and feedback on the choice of the property name, the unambiguity of
the specification document, and a review of any interoperability or
security considerations. The submitter may submit a revised
registration proposal or abandon the registration completely at any
time.
8.2.2. Submit Request to IANA
Registration requests can be sent to <iana@iana.org>.
8.2.3. Designated Expert Review
The primary concern of the designated expert (DE) is preventing name
collisions and encouraging the submitter to document security and
privacy considerations. For a common-use registration, the DE is
expected to confirm that suitable documentation, as described in
Section 4.6 of [RFC8126], is available to ensure interoperability.
That documentation will usually be in an RFC, but simple definitions
are likely to use a web/wiki page, and if a sentence or two is deemed
sufficient, it could be described in the registry itself. The DE
should also verify that the property name does not conflict with work
that is active or already published within the IETF. A published
specification is not required for reserved or obsolete registrations.
The DE will either approve or deny the registration request and
publish a notice of the decision to the Calext WG mailing list or its
successor, as well as inform IANA. A denial notice must be justified
by an explanation, and, in the cases where it is possible, concrete
suggestions on how the request can be modified so as to become
acceptable should be provided.
8.2.4. Change Procedures
Once a JSCalendar property has been published by IANA, the change
controller may request a change to its definition. The same
procedure that would be appropriate for the original registration
request is used to process a change request.
JSCalendar property registrations may not be deleted; properties that
are no longer believed appropriate for use can be declared obsolete
by a change to their "intended usage" field; such properties will be
clearly marked in the IANA registry.
Significant changes to a JSCalendar property's definition should be
requested only when there are serious omissions or errors in the
published specification, as such changes may cause interoperability
issues. When review is required, a change request may be denied if
it renders entities that were valid under the previous definition
invalid under the new definition.
The owner of a JSCalendar property may pass responsibility to another
person or agency by informing IANA; this can be done without
discussion or review.
8.2.5. "JSCalendar Properties" Registry Template
Property Name: This is the name of the property. The property name
MUST NOT already be registered for any of the object types listed
in the "Property Context" field of this registration. Other
object types MAY already have registered a different property with
the same name; however, the same name SHOULD only be used when the
semantics are analogous.
Property Type: This is the type of this property, using type
signatures, as specified in Section 1.3. The property type MUST
be registered in the "JSCalendar Types" registry.
Property Context: This is a comma-separated list of JSCalendar
object types this property is allowed on.
Reference or Description: This is a brief description or RFC number
and section reference where the property is specified (omitted for
"reserved" property names).
Intended Usage: This may be "common", "reserved", or "obsolete".
Change Controller: This is who may request a change to this entry's
definition ("IETF" for RFCs from the IETF stream).
8.2.6. Initial Contents for the "JSCalendar Properties" Registry
The following table lists the initial entries of the "JSCalendar
Properties" registry. All properties are for common use. All RFC
section references are for this document. The change controller for
all these properties is "IETF".
+====================+=================+================+===========+
|Property Name |Property Type |Property Context|Reference |
| | | |or |
| | | |Description|
+====================+=================+================+===========+
|@type |String |Event, Task, |Section |
| | |Group, |4.1.1, |
| | |AbsoluteTrigger,|Section |
| | |Alert, Link, |4.5.2, |
| | |Location, NDay, |Section |
| | |OffsetTrigger, |1.4.11, |
| | |Participant, |Section |
| | |RecurrenceRule, |4.2.5, |
| | |Relation, |Section |
| | |TimeZone, |4.4.6, |
| | |TimeZoneRule, |Section |
| | |VirtualLocation |4.3.3, |
| | | |Section |
| | | |1.4.10, |
| | | |Section |
| | | |4.7.2, |
| | | |Section |
| | | |4.2.6 |
+--------------------+-----------------+----------------+-----------+
|acknowledged |UTCDateTime |Alert |Section |
| | | |4.5.2 |
+--------------------+-----------------+----------------+-----------+
|action |String |Alert |Section |
| | | |4.5.2 |
+--------------------+-----------------+----------------+-----------+
|alerts |Id[Alert] |Event, Task |Section |
| | | |4.5.2 |
+--------------------+-----------------+----------------+-----------+
|aliases |String[Boolean] |TimeZone |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|byDay |NDay[] |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|byHour |UnsignedInt[] |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|byMinute |UnsignedInt[] |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|byMonth |String[] |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|byMonthDay |Int[] |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|bySecond |UnsignedInt[] |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|bySetPosition |Int[] |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|byWeekNo |Int[] |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|byYearDay |Int[] |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|categories |String[Boolean] |Event, Task, |Section |
| | |Group |4.2.10 |
+--------------------+-----------------+----------------+-----------+
|cid |String |Link |Section |
| | | |1.4.11 |
+--------------------+-----------------+----------------+-----------+
|color |String |Event, Task, |Section |
| | |Group |4.2.11 |
+--------------------+-----------------+----------------+-----------+
|comments |String[] |TimeZoneRule |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|contentType |String |Link |Section |
| | | |1.4.11 |
+--------------------+-----------------+----------------+-----------+
|coordinates |String |Location |Section |
| | | |4.2.5 |
+--------------------+-----------------+----------------+-----------+
|count |UnsignedInt |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|created |UTCDateTime |Event, Task, |Section |
| | |Group |4.1.5 |
+--------------------+-----------------+----------------+-----------+
|day |String |NDay |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|daylight |TimeZoneRule[] |TimeZone |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|delegatedFrom |Id[Boolean] |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|delegatedTo |Id[Boolean] |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|description |String |Event, Task, |Section |
| | |Location, |4.2.2, |
| | |Participant, |Section |
| | |VirtualLocation |4.2.5, |
| | | |Section |
| | | |4.4.6, |
| | | |Section |
| | | |4.2.6 |
+--------------------+-----------------+----------------+-----------+
|description |String |Event, Task |Section |
|ContentType | | |4.2.3 |
+--------------------+-----------------+----------------+-----------+
|display |String |Link |Section |
| | | |1.4.11 |
+--------------------+-----------------+----------------+-----------+
|due |LocalDateTime |Task |Section |
| | | |5.2.1 |
+--------------------+-----------------+----------------+-----------+
|duration |Duration |Event |Section |
| | | |5.1.2 |
+--------------------+-----------------+----------------+-----------+
|email |String |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|entries |(Task|Event)[] |Group |Section |
| | | |5.3.1 |
+--------------------+-----------------+----------------+-----------+
|estimatedDuration |Duration |Task |Section |
| | | |5.2.3 |
+--------------------+-----------------+----------------+-----------+
|excluded |Boolean |Event, Task |Section |
| | | |4.3.6 |
+--------------------+-----------------+----------------+-----------+
|excluded |RecurrenceRule[] |Event, Task |Section |
|RecurrenceRules | | |4.3.4 |
+--------------------+-----------------+----------------+-----------+
|expectReply |Boolean |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|features |String[Boolean] |VirtualLocation |Section |
| | | |4.2.6 |
+--------------------+-----------------+----------------+-----------+
|firstDayOfWeek |String |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|freeBusyStatus |String |Event, Task |Section |
| | | |4.4.2 |
+--------------------+-----------------+----------------+-----------+
|frequency |String |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|href |String |Link |Section |
| | | |1.4.11 |
+--------------------+-----------------+----------------+-----------+
|interval |UnsignedInt |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|invitedBy |Id |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|keywords |String[Boolean] |Event, Task, |Section |
| | |Group |4.2.9 |
+--------------------+-----------------+----------------+-----------+
|kind |String |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|language |String |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|links |Id[Link] |Group, Event, |Section |
| | |Task, Location, |4.2.7, |
| | |Participant |Section |
| | | |4.2.5, |
| | | |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|locale |String |Group, Event, |Section |
| | |Task |4.2.8 |
+--------------------+-----------------+----------------+-----------+
|localizations |String |Event, Task |Section |
| |[PatchObject] | |4.6.1 |
+--------------------+-----------------+----------------+-----------+
|locationId |Id |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|locations |Id[Location] |Event, Task |Section |
| | | |4.2.5 |
+--------------------+-----------------+----------------+-----------+
|locationTypes |String[Boolean] |Location |Section |
| | | |4.2.5 |
+--------------------+-----------------+----------------+-----------+
|memberOf |Id[Boolean] |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|method |String |Event, Task |Section |
| | | |4.1.8 |
+--------------------+-----------------+----------------+-----------+
|name |String |Location, |Section |
| | |VirtualLocation,|4.2.5, |
| | |Participant |Section |
| | | |4.2.6, |
| | | |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|names |String[Boolean] |TimeZoneRule |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|nthOfPeriod |Int |NDay |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|offset |SignedDuration |OffsetTrigger |Section |
| | | |4.5.2 |
+--------------------+-----------------+----------------+-----------+
|offsetFrom |UTCDateTime |TimeZoneRule |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|offsetTo |UTCDateTime |TimeZoneRule |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|participants |Id[Participant] |Event, Task |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|participationComment|String |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|participationStatus |String |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|percentComplete |UnsignedInt |Task, |Section |
| | |Participant |5.2.4 |
+--------------------+-----------------+----------------+-----------+
|priority |Int |Event, Task |Section |
| | | |4.4.1 |
+--------------------+-----------------+----------------+-----------+
|privacy |String |Event, Task |Section |
| | | |4.4.3 |
+--------------------+-----------------+----------------+-----------+
|prodId |String |Event, Task, |Section |
| | |Group |4.1.4 |
+--------------------+-----------------+----------------+-----------+
|progress |String |Task, |Section |
| | |Participant |5.2.5 |
+--------------------+-----------------+----------------+-----------+
|progressUpdated |UTCDateTime |Task, |Section |
| | |Participant |5.2.6 |
+--------------------+-----------------+----------------+-----------+
|recurrenceId |LocalDateTime |Event, Task |Section |
| | | |4.3.1 |
+--------------------+-----------------+----------------+-----------+
|recurrenceIdTimeZone|TimeZoneId|null |Event, Task |Section |
| | | |4.3.2 |
+--------------------+-----------------+----------------+-----------+
|recurrenceOverrides |LocalDateTime |Event, Task, |Section |
| |[PatchObject] |TimeZoneRule |4.3.5, |
| | | |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|recurrenceRules |RecurrenceRule[] |Event, Task, |Section |
| | |TimeZoneRule |4.3.3, |
| | | |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|rel |String |Link |Section |
| | | |1.4.11 |
+--------------------+-----------------+----------------+-----------+
|relatedTo |String[Relation] |Event, Task, |Section |
| | |Alert |4.1.3, |
| | | |Section |
| | | |4.5.2 |
+--------------------+-----------------+----------------+-----------+
|relation |String[Boolean] |Relation |Section |
| | | |1.4.10 |
+--------------------+-----------------+----------------+-----------+
|relativeTo |String |OffsetTrigger, |Section |
| | |Location |4.5.2, |
| | | |Section |
| | | |4.2.5 |
+--------------------+-----------------+----------------+-----------+
|replyTo |String[String] |Event, Task |Section |
| | | |4.4.4 |
+--------------------+-----------------+----------------+-----------+
|requestStatus |String |Event, Task |Section |
| | | |4.4.7 |
+--------------------+-----------------+----------------+-----------+
|roles |String[Boolean] |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|rscale |String |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|sentBy |String |Event, Task, |Section |
| | |Participant |4.4.5, |
| | | |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|standard |TimeZoneRule[] |TimeZone |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|start |LocalDateTime |TimeZoneRule |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|scheduleAgent |String |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|scheduleForceSend |Boolean |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|scheduleSequence |UnsignedInt |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|scheduleStatus |String[] |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|scheduleUpdated |UTCDateTime |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|sendTo |String[String] |Participant |Section |
| | | |4.4.6 |
+--------------------+-----------------+----------------+-----------+
|sequence |UnsignedInt |Event, Task |Section |
| | | |4.1.7 |
+--------------------+-----------------+----------------+-----------+
|showWithoutTime |Boolean |Event, Task |Section |
| | | |4.2.4 |
+--------------------+-----------------+----------------+-----------+
|size |UnsignedInt |Link |Section |
| | | |1.4.11 |
+--------------------+-----------------+----------------+-----------+
|skip |String |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|source |String |Group |Section |
| | | |5.3.2 |
+--------------------+-----------------+----------------+-----------+
|start |LocalDateTime |Event, Task |Section |
| | | |5.1.1, |
| | | |Section |
| | | |5.2.2 |
+--------------------+-----------------+----------------+-----------+
|status |String |Event |Section |
| | | |5.1.3 |
+--------------------+-----------------+----------------+-----------+
|timeZone |TimeZoneId|null |Event, Task, |Section |
| | |Location |4.7.1, |
| | | |Section |
| | | |4.2.5 |
+--------------------+-----------------+----------------+-----------+
|timeZones |TimeZoneId |Event, Task |Section |
| |[TimeZone] | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|title |String |Event, Task, |Section |
| | |Group, Link |4.2.1 |
+--------------------+-----------------+----------------+-----------+
|trigger |OffsetTrigger| |Alert |Section |
| |AbsoluteTrigger| | |4.5.2 |
| |UnknownTrigger | | |
+--------------------+-----------------+----------------+-----------+
|tzId |String |TimeZone |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|uid |String |Event, Task, |Section |
| | |Group |4.1.2 |
+--------------------+-----------------+----------------+-----------+
|until |LocalDateTime |RecurrenceRule |Section |
| | | |4.3.3 |
+--------------------+-----------------+----------------+-----------+
|updated |UTCDateTime |Event, Task, |Section |
| | |Group |4.1.6 |
+--------------------+-----------------+----------------+-----------+
|uri |String |VirtualLocation |Section |
| | | |4.2.6 |
+--------------------+-----------------+----------------+-----------+
|url |String |TimeZone |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|useDefaultAlerts |Boolean |Event, Task |Section |
| | | |4.5.1 |
+--------------------+-----------------+----------------+-----------+
|validUntil |UTCDateTime |TimeZone |Section |
| | | |4.7.2 |
+--------------------+-----------------+----------------+-----------+
|virtualLocations |Id |Event, Task |Section |
| |[VirtualLocation]| |4.2.6 |
+--------------------+-----------------+----------------+-----------+
|when |UTCDateTime |AbsoluteTrigger |Section |
| | | |4.5.2 |
+--------------------+-----------------+----------------+-----------+
Table 1: Initial Contents of the "JSCalendar Properties" Registry
8.3. Creation of the "JSCalendar Types" Registry
IANA has created the "JSCalendar Types" registry to avoid name
collisions and provide a complete reference for all data types used
for JSCalendar property values. The registration process is the same
as for the "JSCalendar Properties" registry, as defined in
Section 8.2.
8.3.1. "JSCalendar Types" Registry Template
Type Name: the name of the type
Reference or Description: a brief description or RFC number and
section reference where the Type is specified (may be omitted for
"reserved" type names)
Intended Use: common, reserved, or obsolete
Change Controller: who may request a change to this entry's
definition ("IETF" for RFCs from the IETF stream)
8.3.2. Initial Contents for the "JSCalendar Types" Registry
The following table lists the initial entries of the JSCalendar Types
registry. All properties are for common use. All RFC section
references are for this document. The change controller for all
these properties is "IETF".
+=================+==========================+
| Type Name | Reference or Description |
+=================+==========================+
| Alert | Section 4.5.2 |
+-----------------+--------------------------+
| Boolean | Section 1.3 |
+-----------------+--------------------------+
| Duration | Section 1.4.6 |
+-----------------+--------------------------+
| Id | Section 1.4.1 |
+-----------------+--------------------------+
| Int | Section 1.4.2 |
+-----------------+--------------------------+
| LocalDateTime | Section 1.4.5 |
+-----------------+--------------------------+
| Link | Section 1.4.11 |
+-----------------+--------------------------+
| Location | Section 4.2.5 |
+-----------------+--------------------------+
| NDay | Section 4.3.3 |
+-----------------+--------------------------+
| Number | Section 1.3 |
+-----------------+--------------------------+
| Participant | Section 4.4.6 |
+-----------------+--------------------------+
| PatchObject | Section 1.4.9 |
+-----------------+--------------------------+
| RecurrenceRule | Section 4.3.3 |
+-----------------+--------------------------+
| Relation | Section 1.4.10 |
+-----------------+--------------------------+
| SignedDuration | Section 1.4.7 |
+-----------------+--------------------------+
| String | Section 1.3 |
+-----------------+--------------------------+
| TimeZone | Section 4.7.2 |
+-----------------+--------------------------+
| TimeZoneId | Section 1.4.8 |
+-----------------+--------------------------+
| TimeZoneRule | Section 4.7.2 |
+-----------------+--------------------------+
| UnsignedInt | Section 1.4.3 |
+-----------------+--------------------------+
| UTCDateTime | Section 1.4.4 |
+-----------------+--------------------------+
| VirtualLocation | Section 4.2.6 |
+-----------------+--------------------------+
Table 2: Initial Contents of the
"JSCalendar Types" Registry
8.4. Creation of the "JSCalendar Enum Values" Registry
IANA has created the "JSCalendar Enum Values" registry to allow
interoperable extension of semantics for properties with enumerable
values. Each such property will have a subregistry of allowed
values. The registration process for a new enum value or adding a
new enumerable property is the same as for the "JSCalendar
Properties" registry, as defined in Section 8.2.
8.4.1. "JSCalendar Enum Values" Registry Property Template
This template is for adding a subregistry for a new enumerable
property to the "JSCalendar Enum" registry.
Property Name: These are the name(s) of the property or properties
where these values may be used. This MUST be registered in the
"JSCalendar Properties" registry.
Context: This is the list of allowed object types where the property
or properties may appear, as registered in the "JSCalendar
Properties" registry. This disambiguates where there may be two
distinct properties with the same name in different contexts.
Change Controller: ("IETF" for properties defined in RFCs from the
IETF stream).
Initial Contents: This is the initial list of defined values for
this enum, using the template defined in Section 8.4.2. A
subregistry will be created with these values for this property
name/context tuple.
8.4.2. "JSCalendar Enum Values" Registry Value Template
This template is for adding a new enum value to a subregistry in the
JSCalendar Enum registry.
Enum Value: the verbatim value of the enum
Reference or Description: a brief description or RFC number and
section reference for the semantics of this value
8.4.3. Initial Contents for the "JSCalendar Enum Values" Registry
For each subregistry created in this section, all RFC section
references are for this document.
Property Name: action
Context: Alert
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| display | Section 4.5.2 |
+------------+--------------------------+
| email | Section 4.5.2 |
+------------+--------------------------+
Table 3: JSCalendar Enum Values for
action (Context: Alert)
Property Name: display
Context: Link
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| badge | Section 1.4.11 |
+------------+--------------------------+
| graphic | Section 1.4.11 |
+------------+--------------------------+
| fullsize | Section 1.4.11 |
+------------+--------------------------+
| thumbnail | Section 1.4.11 |
+------------+--------------------------+
Table 4: JSCalendar Enum Values for
display (Context: Link)
Property Name: features
Context: VirtualLocation
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| audio | Section 4.2.6 |
+------------+--------------------------+
| chat | Section 4.2.6 |
+------------+--------------------------+
| feed | Section 4.2.6 |
+------------+--------------------------+
| moderator | Section 4.2.6 |
+------------+--------------------------+
| phone | Section 4.2.6 |
+------------+--------------------------+
| screen | Section 4.2.6 |
+------------+--------------------------+
| video | Section 4.2.6 |
+------------+--------------------------+
Table 5: JSCalendar Enum Values for
features (Context: VirtualLocation)
Property Name: freeBusyStatus
Context: Event, Task
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| free | Section 4.4.2 |
+------------+--------------------------+
| busy | Section 4.4.2 |
+------------+--------------------------+
Table 6: JSCalendar Enum Values for
freeBusyStatus (Context: Event, Task)
Property Name: kind
Context: Participant
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| individual | Section 4.4.6 |
+------------+--------------------------+
| group | Section 4.4.6 |
+------------+--------------------------+
| resource | Section 4.4.6 |
+------------+--------------------------+
| location | Section 4.4.6 |
+------------+--------------------------+
Table 7: JSCalendar Enum Values for
kind (Context: Participant)
Property Name: participationStatus
Context: Participant
Change Controller: IETF
Initial Contents:
+==============+==========================+
| Enum Value | Reference or Description |
+==============+==========================+
| needs-action | Section 4.4.6 |
+--------------+--------------------------+
| accepted | Section 4.4.6 |
+--------------+--------------------------+
| declined | Section 4.4.6 |
+--------------+--------------------------+
| tentative | Section 4.4.6 |
+--------------+--------------------------+
| delegated | Section 4.4.6 |
+--------------+--------------------------+
Table 8: JSCalendar Enum Values for
participationStatus (Context:
Participant)
Property Name: privacy
Context: Event, Task
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| public | Section 4.4.3 |
+------------+--------------------------+
| private | Section 4.4.3 |
+------------+--------------------------+
| secret | Section 4.4.3 |
+------------+--------------------------+
Table 9: JSCalendar Enum Values for
privacy (Context: Event, Task)
Property Name: progress
Context: Task, Participant
Change Controller: IETF
Initial Contents:
+==============+==========================+
| Enum Value | Reference or Description |
+==============+==========================+
| needs-action | Section 5.2.5 |
+--------------+--------------------------+
| in-process | Section 5.2.5 |
+--------------+--------------------------+
| completed | Section 5.2.5 |
+--------------+--------------------------+
| failed | Section 5.2.5 |
+--------------+--------------------------+
| cancelled | Section 5.2.5 |
+--------------+--------------------------+
Table 10: JSCalendar Enum Values for
progress (Context: Task, Participant)
Property Name: relation
Context: Relation
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| first | Section 1.4.10 |
+------------+--------------------------+
| next | Section 1.4.10 |
+------------+--------------------------+
| child | Section 1.4.10 |
+------------+--------------------------+
| parent | Section 1.4.10 |
+------------+--------------------------+
Table 11: JSCalendar Enum Values for
relation (Context: Relation)
Property Name: relativeTo
Context: OffsetTrigger, Location
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| start | Section 4.5.2 |
+------------+--------------------------+
| end | Section 4.5.2 |
+------------+--------------------------+
Table 12: JSCalendar Enum Values for
relativeTo (Context: OffsetTrigger,
Location)
Property Name: roles
Context: Participant
Change Controller: IETF
Initial Contents:
+===============+==========================+
| Enum Value | Reference or Description |
+===============+==========================+
| owner | Section 4.4.6 |
+---------------+--------------------------+
| attendee | Section 4.4.6 |
+---------------+--------------------------+
| optional | Section 4.4.6 |
+---------------+--------------------------+
| informational | Section 4.4.6 |
+---------------+--------------------------+
| chair | Section 4.4.6 |
+---------------+--------------------------+
| contact | Section 4.4.6 |
+---------------+--------------------------+
Table 13: JSCalendar Enum Values for
roles (Context: Participant)
Property Name: scheduleAgent
Context: Participant
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| server | Section 4.4.6 |
+------------+--------------------------+
| client | Section 4.4.6 |
+------------+--------------------------+
| none | Section 4.4.6 |
+------------+--------------------------+
Table 14: JSCalendar Enum Values for
scheduleAgent (Context: Participant)
Property Name: status
Context: Event
Change Controller: IETF
Initial Contents:
+============+==========================+
| Enum Value | Reference or Description |
+============+==========================+
| confirmed | Section 5.1.3 |
+------------+--------------------------+
| cancelled | Section 5.1.3 |
+------------+--------------------------+
| tentative | Section 5.1.3 |
+------------+--------------------------+
Table 15: JSCalendar Enum Values for
status (Context: Event)
9. References
9.1. Normative References
[CLDR] "Unicode Common Locale Data Repository",
<http://cldr.unicode.org/>.
[COLORS] Çelik, T., Lilley, C., and L. Baron, "CSS Color Module
Level 3", W3C Recommendation, June 2018,
<https://www.w3.org/TR/css-color-3/>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2392] Levinson, E., "Content-ID and Message-ID Uniform Resource
Locators", RFC 2392, DOI 10.17487/RFC2392, August 1998,
<https://www.rfc-editor.org/info/rfc2392>.
[RFC2397] Masinter, L., "The "data" URL scheme", RFC 2397,
DOI 10.17487/RFC2397, August 1998,
<https://www.rfc-editor.org/info/rfc2397>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
DOI 10.17487/RFC4122, July 2005,
<https://www.rfc-editor.org/info/rfc4122>.
[RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types
Registry", RFC 4589, DOI 10.17487/RFC4589, July 2006,
<https://www.rfc-editor.org/info/rfc4589>.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<https://www.rfc-editor.org/info/rfc5322>.
[RFC5545] Desruisseaux, B., Ed., "Internet Calendaring and
Scheduling Core Object Specification (iCalendar)",
RFC 5545, DOI 10.17487/RFC5545, September 2009,
<https://www.rfc-editor.org/info/rfc5545>.
[RFC5546] Daboo, C., Ed., "iCalendar Transport-Independent
Interoperability Protocol (iTIP)", RFC 5546,
DOI 10.17487/RFC5546, December 2009,
<https://www.rfc-editor.org/info/rfc5546>.
[RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
September 2009, <https://www.rfc-editor.org/info/rfc5646>.
[RFC5870] Mayrhofer, A. and C. Spanring, "A Uniform Resource
Identifier for Geographic Locations ('geo' URI)",
RFC 5870, DOI 10.17487/RFC5870, June 2010,
<https://www.rfc-editor.org/info/rfc5870>.
[RFC6047] Melnikov, A., Ed., "iCalendar Message-Based
Interoperability Protocol (iMIP)", RFC 6047,
DOI 10.17487/RFC6047, December 2010,
<https://www.rfc-editor.org/info/rfc6047>.
[RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type
Specifications and Registration Procedures", BCP 13,
RFC 6838, DOI 10.17487/RFC6838, January 2013,
<https://www.rfc-editor.org/info/rfc6838>.
[RFC6901] Bryan, P., Ed., Zyp, K., and M. Nottingham, Ed.,
"JavaScript Object Notation (JSON) Pointer", RFC 6901,
DOI 10.17487/RFC6901, April 2013,
<https://www.rfc-editor.org/info/rfc6901>.
[RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493,
DOI 10.17487/RFC7493, March 2015,
<https://www.rfc-editor.org/info/rfc7493>.
[RFC7529] Daboo, C. and G. Yakushev, "Non-Gregorian Recurrence Rules
in the Internet Calendaring and Scheduling Core Object
Specification (iCalendar)", RFC 7529,
DOI 10.17487/RFC7529, May 2015,
<https://www.rfc-editor.org/info/rfc7529>.
[RFC7808] Douglass, M. and C. Daboo, "Time Zone Data Distribution
Service", RFC 7808, DOI 10.17487/RFC7808, March 2016,
<https://www.rfc-editor.org/info/rfc7808>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
[RFC8288] Nottingham, M., "Web Linking", RFC 8288,
DOI 10.17487/RFC8288, October 2017,
<https://www.rfc-editor.org/info/rfc8288>.
[TZDB] IANA, "Time Zone Database",
<https://www.iana.org/time-zones>.
9.2. Informative References
[ISO.9070.1991]
ISO/IEC, "Information technology -- SGML support
facilities -- Registration procedures for public text
owner identifiers", Edition 2, ISO/IEC 9070:1991, April
1991, <https://www.iso.org/standard/16645.html>.
[LINKRELS] IANA, "Link Relations: Link Relation Types",
<https://www.iana.org/assignments/link-relations>.
[LOCATIONTYPES]
IANA, "Location Types Registry",
<https://www.iana.org/assignments/location-type-registry>.
[MEDIATYPES]
IANA, "Media Types",
<https://www.iana.org/assignments/media-types>.
[RFC6376] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed.,
"DomainKeys Identified Mail (DKIM) Signatures", STD 76,
RFC 6376, DOI 10.17487/RFC6376, September 2011,
<https://www.rfc-editor.org/info/rfc6376>.
[RFC7265] Kewisch, P., Daboo, C., and M. Douglass, "jCal: The JSON
Format for iCalendar", RFC 7265, DOI 10.17487/RFC7265, May
2014, <https://www.rfc-editor.org/info/rfc7265>.
[RFC7986] Daboo, C., "New Properties for iCalendar", RFC 7986,
DOI 10.17487/RFC7986, October 2016,
<https://www.rfc-editor.org/info/rfc7986>.
Acknowledgments
The authors would like to thank the members of CalConnect for their
valuable contributions. This specification originated from the work
of the API technical committee of CalConnect: The Calendaring and
Scheduling Consortium.
Authors' Addresses
Neil Jenkins
Fastmail
Collins St. West
P.O. Box 234
Melbourne VIC 8007
Australia
Email: neilj@fastmailteam.com
URI: https://www.fastmail.com
Robert Stepanek
Fastmail
Collins St. West
P.O. Box 234
Melbourne VIC 8007
Australia
Email: rsto@fastmailteam.com
URI: https://www.fastmail.com