Calendaring extensions N. Jenkins
Internet-Draft R. Stepanek
Intended status: Standards Track Fastmail
Expires: April 19, 2021 October 16, 2020
JSCalendar: A JSON representation of calendar data
draft-ietf-calext-jscalendar-32
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, and to be unambiguous, extendable, and simple to process. In
contrast to the jCal format, which is also JSON-based, JSCalendar is
not a direct mapping from iCalendar, but defines the data model
independently and expands semantics where appropriate.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 19, 2021.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Motivation and Relation to iCalendar and jCal . . . . . . 5
1.2. Notational Conventions . . . . . . . . . . . . . . . . . 6
1.3. Type Signatures . . . . . . . . . . . . . . . . . . . . . 6
1.4. Data Types . . . . . . . . . . . . . . . . . . . . . . . 7
1.4.1. Id . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4.2. Int . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4.3. UnsignedInt . . . . . . . . . . . . . . . . . . . . . 8
1.4.4. UTCDateTime . . . . . . . . . . . . . . . . . . . . . 8
1.4.5. LocalDateTime . . . . . . . . . . . . . . . . . . . . 8
1.4.6. Duration . . . . . . . . . . . . . . . . . . . . . . 9
1.4.7. SignedDuration . . . . . . . . . . . . . . . . . . . 10
1.4.8. TimeZoneId . . . . . . . . . . . . . . . . . . . . . 10
1.4.9. PatchObject . . . . . . . . . . . . . . . . . . . . . 11
1.4.10. Relation . . . . . . . . . . . . . . . . . . . . . . 12
1.4.11. Link . . . . . . . . . . . . . . . . . . . . . . . . 12
2. JSCalendar Objects . . . . . . . . . . . . . . . . . . . . . 14
2.1. JSEvent . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.2. JSTask . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3. JSGroup . . . . . . . . . . . . . . . . . . . . . . . . . 14
3. Structure of JSCalendar Objects . . . . . . . . . . . . . . . 15
3.1. Object Type . . . . . . . . . . . . . . . . . . . . . . . 15
3.2. Normalization and Equivalence . . . . . . . . . . . . . . 15
3.3. Vendor-specific Property Extensions, Values and Types . . 15
4. Common JSCalendar Properties . . . . . . . . . . . . . . . . 16
4.1. Metadata Properties . . . . . . . . . . . . . . . . . . . 16
4.1.1. @type . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.2. uid . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.3. relatedTo . . . . . . . . . . . . . . . . . . . . . . 17
4.1.4. prodId . . . . . . . . . . . . . . . . . . . . . . . 17
4.1.5. created . . . . . . . . . . . . . . . . . . . . . . . 17
4.1.6. updated . . . . . . . . . . . . . . . . . . . . . . . 18 17
4.1.7. sequence . . . . . . . . . . . . . . . . . . . . . . 18
4.1.8. method . . . . . . . . . . . . . . . . . . . . . . . 18
4.2. What and Where Properties . . . . . . . . . . . . . . . . 18
4.2.1. title . . . . . . . . . . . . . . . . . . . . . . . . 18
4.2.2. description . . . . . . . . . . . . . . . . . . . . . 18
4.2.3. descriptionContentType . . . . . . . . . . . . . . . 18
4.2.4. showWithoutTime . . . . . . . . . . . . . . . . . . . 19
4.2.5. locations . . . . . . . . . . . . . . . . . . . . . . 19
4.2.6. virtualLocations . . . . . . . . . . . . . . . . . . 20
4.2.7. links . . . . . . . . . . . . . . . . . . . . . . . . 21
4.2.8. locale . . . . . . . . . . . . . . . . . . . . . . . 21
4.2.9. keywords . . . . . . . . . . . . . . . . . . . . . . 22 21
4.2.10. categories . . . . . . . . . . . . . . . . . . . . . 22
4.2.11. color . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3. Recurrence Properties . . . . . . . . . . . . . . . . . . 22
4.3.1. recurrenceId . . . . . . . . . . . . . . . . . . . . 23
4.3.2. recurrenceRules . . . . . . . . . . . . . . . . . . . 23
4.3.3. excludedRecurrenceRules . . . . . . . . . . . . . . . 31
4.3.4. recurrenceOverrides . . . . . . . . . . . . . . . . . 32
4.3.5. excluded . . . . . . . . . . . . . . . . . . . . . . 33
4.4. Sharing and Scheduling Properties . . . . . . . . . . . . 33
4.4.1. priority . . . . . . . . . . . . . . . . . . . . . . 33
4.4.2. freeBusyStatus . . . . . . . . . . . . . . . . . . . 33
4.4.3. privacy . . . . . . . . . . . . . . . . . . . . . . . 34
4.4.4. replyTo . . . . . . . . . . . . . . . . . . . . . . . 35
4.4.5. participants . . . . . . . . . . . . . . . . . . . . 35
4.5. Alerts Properties . . . . . . . . . . . . . . . . . . . . 41
4.5.1. useDefaultAlerts . . . . . . . . . . . . . . . . . . 41
4.5.2. alerts . . . . . . . . . . . . . . . . . . . . . . . 41
4.6. Multilingual Properties . . . . . . . . . . . . . . . . . 43
4.6.1. localizations . . . . . . . . . . . . . . . . . . . . 43
4.7. Time Zone Properties . . . . . . . . . . . . . . . . . . 44
4.7.1. timeZone . . . . . . . . . . . . . . . . . . . . . . 44
4.7.2. timeZones . . . . . . . . . . . . . . . . . . . . . . 44
5. Type-specific JSCalendar Properties . . . . . . . . . . . . . 47
5.1. JSEvent Properties . . . . . . . . . . . . . . . . . . . 47
5.1.1. start . . . . . . . . . . . . . . . . . . . . . . . . 47
5.1.2. duration . . . . . . . . . . . . . . . . . . . . . . 47
5.1.3. status . . . . . . . . . . . . . . . . . . . . . . . 47
5.2. JSTask Properties . . . . . . . . . . . . . . . . . . . . 48
5.2.1. due . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.2.2. start . . . . . . . . . . . . . . . . . . . . . . . . 48
5.2.3. estimatedDuration . . . . . . . . . . . . . . . . . . 48
5.2.4. percentComplete . . . . . . . . . . . . . . . . . . . 48
5.2.5. progress . . . . . . . . . . . . . . . . . . . . . . 48
5.2.6. progressUpdated . . . . . . . . . . . . . . . . . . . 49
5.3. JSGroup Properties . . . . . . . . . . . . . . . . . . . 49
5.3.1. entries . . . . . . . . . . . . . . . . . . . . . . . 50
5.3.2. source . . . . . . . . . . . . . . . . . . . . . . . 50
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.1. Simple event . . . . . . . . . . . . . . . . . . . . . . 51
6.2. Simple task . . . . . . . . . . . . . . . . . . . . . . . 51
6.3. Simple group . . . . . . . . . . . . . . . . . . . . . . 51
6.4. All-day event . . . . . . . . . . . . . . . . . . . . . . 52
6.5. Task with a due date . . . . . . . . . . . . . . . . . . 52
6.6. Event with end time zone . . . . . . . . . . . . . . . . 53
6.7. Floating-time event (with recurrence) . . . . . . . . . . 53
6.8. Event with multiple locations and localization . . . . . 54
6.9. Recurring event with overrides . . . . . . . . . . . . . 55
6.10. Recurring event with participants . . . . . . . . . . . . 56
7. Security Considerations . . . . . . . . . . . . . . . . . . . 58
7.1. Expanding Recurrences . . . . . . . . . . . . . . . . . . 58
7.2. JSON Parsing . . . . . . . . . . . . . . . . . . . . . . 59
7.3. URI Values . . . . . . . . . . . . . . . . . . . . . . . 59
7.4. Spam . . . . . . . . . . . . . . . . . . . . . . . . . . 60
7.5. Duplication . . . . . . . . . . . . . . . . . . . . . . . 60
7.6. Time Zones . . . . . . . . . . . . . . . . . . . . . . . 60
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 61
8.1. Media Type Registration . . . . . . . . . . . . . . . . . 61
8.2. Creation of "JSCalendar Properties" Registry . . . . . . 62
8.2.1. Preliminary Community Review . . . . . . . . . . . . 63
8.2.2. Submit Request to IANA . . . . . . . . . . . . . . . 63
8.2.3. Designated Expert Review . . . . . . . . . . . . . . 63
8.2.4. Change Procedures . . . . . . . . . . . . . . . . . . 63 64
8.2.5. JSCalendar Properties Registry Template . . . . . . . 64
8.2.6. Initial Contents for the JSCalendar Properties
Registry . . . . . . . . . . . . . . . . . . . . . . 64 65
8.3. Creation of "JSCalendar Types" Registry . . . . . . . . . 73
8.3.1. JSCalendar Types Registry Template . . . . . . . . . 73
8.3.2. Initial Contents for the JSCalendar Types Registry . 73
8.4. Creation of "JSCalendar Enum Values" Registry . . . . . . 74
8.4.1. JSCalendar Enum Property Template . . . . . . . . . . 74 75
8.4.2. JSCalendar Enum Value Template . . . . . . . . . . . 75
8.4.3. Initial Contents for the JSCalendar Enum Values
registry . . . . . . . . . . . . . . . . . . . . . . 75
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 81
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 81
10.1. Normative References . . . . . . . . . . . . . . . . . . 82
10.2. Informative References . . . . . . . . . . . . . . . . . 84
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 85
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:
o 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 modelled accurately.
o Wherever possible, there should be only one way to express the
desired semantics, reducing complexity.
o The data model should avoid ambiguities, which often lead to
interoperability issues between implementations.
o 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.
o Extensions, such as new properties and components, should not
require updates to this document.
The representation of this data model is defined in the I-JSON format
[RFC7493], which is a strict subset of the JavaScript Object Notation
(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 while, but contains some ambiguities and pitfalls
that can not be overcome without backward-incompatible changes.
Sources of implementation errors include the following:
o iCalendar defines various formats for local times, UTC time, and
dates.
o iCalendar requires custom time zone definitions within a single
calendar component.
o iCalendar's definition of recurrence rules is ambiguous and has
resulted in differing understandings even between experienced
calendar developers.
o 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 timezone'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, three periods "..."
are 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:
o "*" - The type is undefined (the value could be any type, although
permitted values may be constrained by the context of this value).
o "String" - The JSON string type.
o "Number" - The JSON number type.
o "Boolean" - The JSON boolean type.
o "A[B]" - A JSON object where the keys are all of type "A", and the
values are all of type "B".
o "A[]" - An array of values of type "A".
o "A|B" - The value is either of type "A" or of type "B".
Other types may also be given, with their representations 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 JSEvent objects might use the
same Ids in their respective "links" properties. Or within the same
JSEvent object the same Id could appear in the "participants" and
"alerts" properties. These situations do not imply any semantic
connections among the objects.
Nevertheless, a UUID [RFC4122] is typically a good choice.
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 [RFC3339] "date-time" 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 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) and 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 ISO8601 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 7 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 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 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:
o If null, remove the property from the patched object. If the key
is not present in the parent, this a no-op.
o Anything else: The value to set 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). A "@type" property in a patch MUST be handled as any
other patched property value.
Implementations MUST reject in its entirety a PatchObject if any of
its patches is 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:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "Relation".
o relation: "String[Boolean]" (optional, default: empty Object)
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, or specified
in the property definition where the Relation object is used, or 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 the 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:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "Link".
o href: "String" (mandatory)
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.
o cid: "String" (optional)
This MUST be a valid "content-id" value according to the
definition of Section 2 in [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.
o contentType: "String" (optional)
The media type [RFC6838] of the resource, if known.
o size: "UnsignedInt" (optional)
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.
o rel: "String" (optional)
Identifies the relation of the linked resource to the object. If
set, the value MUST be a relation type from the IANA registry
[LINKRELS], as established in [RFC8288].
o display: "String" (optional)
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.
o title: "String" (optional)
A human-readable plain-text description of the resource.
2. JSCalendar Objects
This section describes the calendar object types specified by
JSCalendar.
2.1. JSEvent
Media type: "application/jscalendar+json;type=jsevent"
A JSEvent 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 "jsevent". "JSEvent".
2.2. JSTask
Media type: "application/jscalendar+json;type=jstask"
A JSTask represents an action-item, assignment, to-do or work item.
It may start and be due at certain points in time, may take some
estimated time to complete, and may recur, none of which is required.
The @type (Section 4.1.1) property value MUST be "jstask". "JSTask".
2.3. JSGroup
Media type: "application/jscalendar+json;type=jsgroup"
A JSGroup is a collection of JSEvent (Section 2.1) and/or JSTask
(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 "jsgroup". "JSGroup".
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:
o 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.
o 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 a "@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).
Specifies the type which this object represents. This MUST be one of
the following values:
o "jsevent": a JSCalendar event (Section 2.1).
o "jstask": a JSCalendar task (Section 2.2).
o "jsgroup": a JSCalendar group (Section 2.3). The allowed value differs
by object type and is defined in sections Section 2.1, Section 2.2,
and Section 2.3
4.1.2. uid
Type: "String" (mandatory).
A globally unique identifier, used to associate the object as the
same across different systems, calendars and views. The value of
this property MUST be unique across all JSCalendar objects, even if
they are of different type. [RFC4122] describes a range of
established algorithms to generate universally unique identifiers
(UUID). UUID version 4, described in Section 4.4 of [RFC4122], is
RECOMMENDED.
For compatibility with [RFC5545] UIDs, 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).
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 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).
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 an 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
non-standard properties, a practice that is known to cause long-term
interoperability problems.
4.1.5. created
Type: "UTCDateTime" (optional).
The date and time this object was initially created.
4.1.6. updated
Type: "UTCDateTime" (mandatory).
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 4.4.5).
This is used as part of iTIP [RFC5546] to know which version of the
object a scheduling message relates to.
4.1.8. method
Type: "String" (optional).
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).
A short summary of the object.
4.2.2. description
Type: "String" (optional, default: empty String).
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").
Describes the media type [RFC6838] of the contents of the
"description" property. Media types MUST be sub-types 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).
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).
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.
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "Location".
o name: "String" (optional)
The human-readable name of the location.
o description: "String" (optional)
Human-readable, plain-text instructions for accessing this
location. This may be an address, set of directions, door access
code, etc.
o locationTypes: "String[Boolean]" (optional)
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.
o relativeTo: "String" (optional)
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.
o timeZone: "TimeZoneId" (optional)
A time zone for this location.
o coordinates: "String" (optional)
A "geo:" URI [RFC5870] for the location.
o links: "Id[Link]" (optional)
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).
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.
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be
"VirtualLocation".
o name: "String" (optional, default: empty String)
The human-readable name of the virtual location.
o description: "String" (optional)
Human-readable plain-text instructions for accessing this virtual
location. This may be a conference access code, etc.
o uri: "String" (mandatory)
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.
4.2.7. links
Type: "Id[Link]" (optional).
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 as
attachments for download.
Links with a rel of "describedby" MUST be considered by the client to
be an alternative representation of the description.
Links with a rel of "icon" MUST be considered by the client to be an
image 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).
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).
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).
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 typically are 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).
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 master 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 4.3.2) generates a set of
extra date-times on which the object occurs.
2. The excludedRecurrenceRules property (Section 4.3.3) 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 4.3.4) defines date-
times which 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 master event, or added as a key to the "recurrenceOverrides"
property of the master event.
4.3.2. recurrenceRules
Type: "RecurrenceRule[]" (optional).
Defines a set of recurrence rules (repeating patterns) for recurring
calendar objects.
A JSEvent recurs by applying the recurrence rules to the "start"
date-time.
A JSTask 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 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:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "RecurrenceRule".
o frequency: "String" (mandatory)
The time span covered by each iteration of this recurrence rule
(see Section 4.3.2.1 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.
o interval: "UnsignedInt" (optional, default: 1)
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.
o rscale: "String" (optional, default: "gregorian")
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.
o skip: "String" (optional, default: "omit")
The behaviour 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.
o firstDayOfWeek: "String" (optional, default: "mo")
The day on which the week is considered to start, represented as a
lowercase abbreviated 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.
o byDay: "NDay[]" (optional)
Days of the week on which to repeat. An "NDay" object has the
following properties:
* @type: "String" (mandatory)
Specifies the type of this object. This MUST be "NDay".
* day: "String" (mandatory)
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 nth-last of period.
This is the ordinal part of the BYDAY value in iCalendar (e.g.,
1 or -3).
o byMonthDay: "Int[]" (optional)
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.
o byMonth: "String[]" (optional)
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.
o byYearDay: "Int[]" (optional)
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.
o byWeekNo: "Int[]" (optional)
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.
o byHour: "UnsignedInt[]" (optional)
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.
o byMinute: "UnsignedInt[]" (optional)
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.
o bySecond: "UnsignedInt[]" (optional)
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.
o bySetPosition: "Int[]" (optional)
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.
o count: "UnsignedInt" (optional)
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.
o until: "LocalDateTime" (optional)
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: 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.
4.3.2.1. Interpreting recurrence rules
A recurrence rule specifies a set of date-times for recurring
calendar objects. A recurrence rule has the following semantics.
Note, 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 1st day of a year
(inclusive) to midnight the 1st 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 1st day of a
month (inclusive) to midnight on the 1st 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 7 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": the second itself, only.
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 means 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., 31st
February 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, 30th February and 31st February 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 indexes from the end of the list, with -1
being the last item.
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; 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) as outlined before.
3. The following properties MUST be implicitly added to the rule
under the given conditions:
* If frequency is not "secondly" and 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 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 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 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 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 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 is 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.
4.3.3. excludedRecurrenceRules
Type: "RecurrenceRule[]" (optional).
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 4.3.2), with
the exception that the initial date-time to which the rule is applied
(the "start" date-time for events; 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 are then removed from those
generated by the recurrenceRules property, as described in
Section 4.3.
4.3.4. recurrenceOverrides
Type: "LocalDateTime[PatchObject]" (optional).
A map of the recurrence ids (the date-time produced by the recurrence
rule) to an object of patches to apply to the generated occurrence
object.
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:
o @type
o excludedRecurrenceRules
o method
o privacy
o prodId
o recurrenceId
o recurrenceOverrides
o recurrenceRules
o relatedTo
o replyTo
o uid
4.3.5. excluded
Type: "Boolean" (optional, default: false).
Defines if this object is an overridden, excluded instance of a
recurring JSCalendar object (see Section 4.3.4). 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 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).
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").
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):
o "free": The object should be ignored when calculating whether the
user is busy.
o "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 are 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".
o "public": The full details of the object are visible to those whom
the object's calendar is shared with.
o "private": The details of the object are hidden; only the basic
time and metadata is shared. The following properties MAY be
shared, any other properties MUST NOT be shared:
* @type
* created
* due
* duration
* estimatedDuration
* freeBusyStatus
* privacy
* recurrenceOverrides. Only patches which apply to another
permissible property are allowed to be shared.
* sequence
* showWithoutTime
* start
* timeZone
* timeZones
* uid
* updated
o "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).
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:
o "imip": The organizer accepts an iMIP [RFC6047] response at this
email address. The value MUST be a "mailto:" URI.
o "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.
o "other": The organizer is identified by this URI but the method
for submitting the response is undefined.
4.4.5. participants
Type: "Id[Participant]" (optional).
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:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "Participant".
o name: "String" (optional)
The display name of the participant (e.g., "Joe Bloggs").
o email: "String" (optional)
The email address for the participant.
o description: "String" (optional).
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.
o sendTo: "String[String]" (optional)
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.
o kind: "String" (optional)
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
o roles: "String[Boolean]" (mandatory)
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. Non-owner participants may only
change properties that just affect 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.
o locationId: "String" (optional)
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.
o language: "String" (optional)
The language tag as defined in [RFC5646] that best describes the
participant's preferred language, if known.
o participationStatus: "String" (optional, default: "needs-action")
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 yet 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.
o participationComment: "String" (optional)
A note from the participant to explain their participation status.
o expectReply: "Boolean" (optional, default: false)
If true, the organizer is expecting the participant to notify them
of their participation status.
o scheduleAgent: "String" (optional, default: "server")
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.
o 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.
o scheduleSequence: "UnsignedInt" (optional, default: 0)
The sequence number of the last response from the participant. If
defined, this MUST be a non-negative 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.
o scheduleStatus: "String[]" (optional)
A list of status codes, as defined in Section 3.8.8.3 of
[RFC5545], returned from the processing of the most recent
scheduling message sent to this participant.
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.
o scheduleUpdated: "UTCDateTime" (optional)
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.
o invitedBy: "String" (optional)
The participant id of the participant who invited this one, if
known.
o delegatedTo: "String[Boolean]" (optional)
A 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).
o delegatedFrom: "String[Boolean]" (optional)
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).
o memberOf: "String[Boolean]" (optional)
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).
o links: "Id[Link]" (optional)
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).
o progress: "String" (optional; only allowed for participants of a
JSTask). 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.
o progressUpdated: "UTCDateTime" (optional; only allowed for
participants of a JSTask). Specifies the date-time the progress
property was last set on this participant. See Section 5.2.6 for
allowed values and semantics.
o percentComplete: "UnsignedInt" (optional; only allowed for
participants of a JSTask). Represents the percent completion of
the participant for this task. The property value MUST be a
positive integer between 0 and 100.
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).
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:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "Alert".
o trigger: "OffsetTrigger|AbsoluteTrigger|UnknownTrigger"
(mandatory)
Defines when to trigger the alert. New types may be defined in
future documents.
An "OffsetTrigger" object has the following properties:
* @type: "String" (mandatory)
Specifies the type of this object. This MUST be
"OffsetTrigger".
* offset: "SignedDuration" (mandatory).
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.
* relativeTo: "String" (optional, default: "start")
Specifies the time property that the alert offset is relative
to. The value MUST be one of:
+ "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)
Specifies the type of this object. This MUST be
"AbsoluteTrigger".
* when: "UTCDateTime" (mandatory).
Defines a specific UTC date-time when the alert is triggered.
An "UnknownTrigger" object is an object that contains a "@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.
o 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 master
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 successfully carried out.
o relatedTo: "String[Relation]" (optional)
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.
o action: "String" (optional, default: "display")
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 about 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 of language tags [RFC5646] to patch objects, which localize the
calendar object into the locale of the respective language tag.
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:
o title
o description
o 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).
Identifies the time zone the object is scheduled in, or 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).
Maps identifiers of custom time zones to their time zone definitions.
The following restrictions apply for each key in the map:
o To avoid conflict with names in the IANA Time Zone Database
[TZDB], it MUST start with the "/" character.
o It MUST be a valid "paramtext" value as specified in Section 3.1.
of [RFC5545].
o 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. A
JSCalendar object may be part in a hierarchy of other JSCalendar
objects (say, a JSEvent is an entry in a JSGroup). 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 JSEvent, a
time zone definition in its timeZones property has precedence over a
definition of the same id in the JSGroup). Time zone definitions in
any children of the calendar object MUST be ignored.
A TimeZone object maps a VTIMEZONE component from iCalendar [RFC5545]
and the semantics are as defined there. A valid time zone MUST
define at least one transition rule in the "standard" or "daylight"
property. Its properties are:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "TimeZone".
o tzId: "String" (mandatory).
The TZID property from iCalendar.
o updated: "UTCDateTime" (optional)
The LAST-MODIFIED property from iCalendar.
o url: "String" (optional)
The TZURL property from iCalendar.
o validUntil: "UTCDateTime" (optional)
The TZUNTIL property from iCalendar specified in [RFC7808].
o aliases: "String[Boolean]" (optional)
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.
o standard: "TimeZoneRule[]" (optional)
The STANDARD sub-components from iCalendar. The order MUST be
preserved during conversion.
o daylight: "TimeZoneRule[]" (optional).
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:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "TimeZoneRule".
o start: "LocalDateTime" (mandatory)
The DTSTART property from iCalendar.
o offsetFrom: "String" (mandatory)
The TZOFFSETFROM property from iCalendar.
o offsetTo: "String" (mandatory)
The TZOFFSETTO property from iCalendar.
o recurrenceRules: "RecurrenceRule[]" (optional)
The RRULE property mapped as specified in Section 4.3.2. During
recurrence rule evaluation, the "until" property value MUST be
interpreted as a local time in the UTC time zone.
o recurrenceOverrides: "LocalDateTime[PatchObject]" (optional)
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 ({}).
o names: "String[Boolean]" (optional)
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.
o comments: "String[]" (optional). Maps the COMMENT properties from
iCalendar. The order MUST be preserved during conversion.
5. Type-specific JSCalendar Properties
5.1. JSEvent Properties
In addition to the common JSCalendar object properties (Section 4) a
JSEvent has the following properties:
5.1.1. start
Type: "LocalDateTime" (mandatory).
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").
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.
A JSEvent MAY involve start and end locations that are in different
time zones (e.g., a trans-continental flight). This can be expressed
using the "relativeTo" and "timeZone" properties of the JSEvent's
Location objects (see Section 4.2.5).
5.1.3. status
Type: "String" (optional, default: "confirmed").
The scheduling status (Section 4.4) of a JSEvent. 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):
o "confirmed": Indicates the event is definitely happening.
o "cancelled": Indicates the event has been cancelled.
o "tentative": Indicates the event may happen.
5.2. JSTask Properties
In addition to the common JSCalendar object properties (Section 4) a
JSTask has the following properties:
5.2.1. due
Type: "LocalDateTime" (optional).
The date/time the task is due in the task's time zone.
5.2.2. start
Type: "LocalDateTime" (optional).
The date/time the task should start in the task's time zone.
5.2.3. estimatedDuration
Type: "Duration" (optional).
Specifies the estimated positive duration of time the task takes to
complete.
5.2.4. percentComplete
Type: "UnsignedInt" (optional).
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).
Defines the progress of this task. If omitted, the default progress
(Section 4.4) of a JSTask is defined as follows (in order of
evaluation):
o "completed": if the "progress" property value of all participants
is "completed".
o "failed": if at least one "progress" property value of a
participant is "failed".
o "in-process": if at least one "progress" property value of a
participant is "in-process".
o "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):
o "needs-action": Indicates the task needs action.
o "in-process": Indicates the task is in process.
o "completed": Indicates the task is completed.
o "failed": Indicates the task failed.
o "cancelled": Indicates the task was cancelled.
5.2.6. progressUpdated
Type: "UTCDateTime" (optional).
Specifies the date/time the "progress" property of either the task
overall (Section 5.2.5) or a specific participant (Section 4.4.5) 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 JSTask into a current, single
instance of JSTask with this instance progress update time and a
future recurring instance. See also Section 4.1.3 on splitting.
5.3. JSGroup Properties
JSGroup supports the following common JSCalendar properties
(Section 4):
o @type
o uid
o prodId
o created
o updated
o title
o description
o descriptionContentType
o links
o locale
o keywords
o categories
o color
o timeZones
In addition, the following JSGroup-specific properties are supported:
5.3.1. entries
Type: "(JSTask|JSEvent)[]" (mandatory).
A collection of group members. Implementations MUST ignore entries
of unknown type.
5.3.2. source
Type: "String" (optional).
The source from which updated versions of this group may be retrieved
from. 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 1pm New York local
time and ends after 1 hour.
{
"@type": "jsevent", "JSEvent",
"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": "jstask", "JSTask",
"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": "jsgroup", "JSGroup",
"uid": "bf0ac22b-4989-4caf-9ebd-54301b4ee51a",
"updated": "2020-01-15T18:00:00Z",
"name": "A simple group",
"entries": [{
"@type": "jsevent", "JSEvent",
"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": "jstask", "JSTask",
"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 6pm 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 9am 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": {
"418d0b9b-b656-4b3c-909f-5b149ca779c9": {
"@type": "Location",
"rel": "start",
"name": "Frankfurt Airport (FRA)"
},
"c2c7ac67-dc13-411e-a7d4-0780fb61fb08": {
"@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
7am 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": {
"1": {
"@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 groesste Musikereignis an!",
"virtualLocations/1/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 9am 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 10am. Also, the location of the exam differs from the
usual location. On April 1 no course is held. On January 7 at 2pm
is an optional introduction course, that occurs before the first
regular lecture.
{
"...": "",
"title": "Calculus I",
"start": "2020-01-08T09:00:00",
"timeZone": "Europe/London",
"duration": "PT1H30M",
"locations": {
"0dfb8ace-aad1-4734-b3b4-a2fe3d6ae1c5": {
"@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": {
"84d639ca-37ac-4a86-81e5-9bbba8eb4053": {
"@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 9am 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": {
"3f41b47b-a5eb-494f-90eb-19d279486d84": {
"@type": "VirtualLocation",
"name": "ChatMe meeting room",
"uri": "https://chatme.example.com?id=1234567&pw=a8a24627b63d396e"
}
},
"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 the patterns of behavior of the user in both the
physical and cyber realm. Additionally, calendar events and tasks
can could 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 organiser 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 just 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, 9am 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 generally
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
DKIM [RFC6376] can help establish the source of messages and
associate the data with existing relationships (such as an address
book contact). Misclassifications are always possible, however, 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 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, with the value being one of "jsevent", "jstask", or
"jsgroup". part. The allowed parameter MUST NOT occur more than once. It MUST
match the value of values correspond to the
"@type" property of the JSON-formatted JSCalendar object in the body.
body:
* "jsevent": the "@type" property value MUST be "JSEvent"
* "jstask": the "@type" property value MUST be "JSTask"
* "jsgroup": the "@type" property value MUST be "JSGroup"
No other parameter values are allowed. The parameter MUST NOT
occur more than once.
Optional parameters: none
Encoding considerations: Same as encoding considerations of
application/json as specified in RFC8529, Section 11 [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 might arise,
or ambiguities in interpretation. 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: This specification.
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 "JSCalendar Properties" Registry
The IANA will create 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 use" 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 use of "common", "reserved", or
"obsolete". The IANA will list common-use registrations prominently
and separately from those with other intended use 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 sanity checking 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.
Properties 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 the 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 use" field; such properties will be
clearly marked in the lists published by the IANA.
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 the IANA; this can be done without
discussion or review.
8.2.5. JSCalendar Properties Registry Template
o Property Name: 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.
o Property Type: The type of this property, using type signatures as
specified in Section 1.3. The property type MUST be registed in
the Type Registry.
o Property Context: A comma-separated list of JSCalendar object
types this property is allowed on.
o Reference or Description: A brief description or RFC number and
section reference where the property is specified (omitted for
"reserved" property names).
o Intended Use: Common, reserved, or obsolete.
o Change Controller: Who may request a change to this entry's
definition ("IETF" for IETF-stream RFCs).
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 | Referen |
| | | Context | ce or D |
| | | | escript |
| | | | ion |
+---------------+----------------------------+------------+---------+
| @type | String | JSEvent, | Section |
| | | JSTask, | 4.1.1, |
| | | JSGroup, A | Section |
| | | bsoluteTri | 4.5.2, |
| | | gger, | Section |
| | | Alert, | 1.4.11 |
| | | Link, | , Secti |
| | | Location, | on 4.2. |
| | | NDay, Offs | 5, Sect |
| | | etTrigger, | ion 4.4 |
| | | Participan | .5, Sec |
| | | t, Recurre | tion 4. |
| | | nceRule, | 3.2, Se |
| | | Relation, | ction 4 |
| | | TimeZone, | .1.3, S |
| | | TimeZoneRu | ection |
| | | le, Virtua | 4.7.2, |
| | | lLocation | 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] | JSEvent, | Section |
| | | JSTask | 4.5.2 |
| | | | |
| aliases | String[Boolean] | TimeZone | Section |
| | | | 4.7.2 |
| | | | |
| byDay | NDay[] | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| byHour | UnsignedInt[] | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| byMinute | UnsignedInt[] | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| byMonth | String[] | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| byMonthDay | Int[] | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| bySecond | UnsignedInt[] | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| bySetPosition | Int[] | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| byWeekNo | Int[] | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| byYearDay | Int[] | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| categories | String[Boolean] | JSEvent, | Section |
| | | JSTask, | 4.2.10 |
| | | JSGroup | |
| | | | |
| cid | String | Link | Section |
| | | | 1.4.11 |
| | | | |
| color | String | JSEvent, | Section |
| | | JSTask, | 4.2.11 |
| | | JSGroup | |
| | | | |
| comments | String[] | TimeZoneRu | Section |
| | | le | 4.7.2 |
| | | | |
| contentType | String | Link | Section |
| | | | 1.4.11 |
| | | | |
| coordinates | String | Location | Section |
| | | | 4.2.5 |
| | | | |
| count | UnsignedInt | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| created | UTCDateTime | JSEvent, | Section |
| | | JSTask, | 4.1.5 |
| | | JSGroup | |
| | | | |
| day | String | NDay | Section |
| | | | 4.3.2 |
| | | | |
| daylight | TimeZoneRule TimeZoneRule[] | TimeZone | Section |
| | | | 4.7.2 |
| | | | |
| delegatedFrom | String[Boolean] | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| delegatedTo | String[Boolean] | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| description | String | JSEvent, | Section |
| | | JSTask, | 4.2.2, |
| | | Location, | Section |
| | | Participan | 4.2.5, |
| | | t, Virtual | Section |
| | | Location | 4.4.5, |
| | | | Section |
| | | | 4.2.6 |
| | | | |
| descriptionCo | String | JSEvent, | Section |
| ntentType | | JSTask | 4.2.3 |
| | | | |
| display | String | Link | Section |
| | | | 1.4.11 |
| | | | |
| due | LocalDateTime | JSTask | Section |
| | | | 5.2.1 |
| | | | |
| duration | Duration | JSEvent | Section |
| | | | 5.1.2 |
| | | | |
| email | String | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| entries | (JSTask|JSEvent)[] | JSGroup | Section |
| | | | 5.3.1 |
| | | | |
| estimatedDura | Duration | JSTask | Section |
| tion | | | 5.2.3 |
| | | | |
| excluded | Boolean | JSEvent, | Section |
| | | JSTask | 4.3.5 |
| | | | |
| excludedRecur | RecurrenceRule[] | JSEvent, | Section |
| renceRules | | JSTask | 4.3.3 |
| | | | |
| expectReply | Boolean | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| firstDayOfWee | String | Recurrence | Section |
| k | | Rule | 4.3.2 |
| | | | |
| freeBusyStatu | String | JSEvent, | Section |
| s | | JSTask | 4.4.2 |
| | | | |
| frequency | String | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| href | String | Link | Section |
| | | | 1.4.11 |
| | | | |
| interval | UnsignedInt | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| invitedBy | String | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| keywords | String[Boolean] | JSEvent, | Section |
| | | JSTask, | 4.2.9 |
| | | JSGroup | |
| | | | |
| kind | String | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| language | String | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| links | Id[Link] | JSGroup, | Section |
| | | JSEvent, | 4.2.7, |
| | | JSTask, | Section |
| | | Location, | 4.2.5, |
| | | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| locale | String | JSGroup, | Section |
| | | JSEvent, | 4.2.8 |
| | | JSTask | |
| | | | |
| localizations | String[PatchObject] | JSEvent, | Section |
| | | JSTask | 4.6.1 |
| | | | |
| locationId | String | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| locations | Id[Location] | JSEvent, | Section |
| | | JSTask | 4.2.5 |
| | | | |
| locationTypes | String[Boolean] | Location | Section |
| | | | 4.2.5 |
| | | | |
| memberOf | String[Boolean] | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| method | String | JSEvent, | Section |
| | | JSTask | 4.1.8 |
| | | | |
| name | String | Location, | Section |
| | | VirtualLoc | 4.2.5, |
| | | ation, Par | Section |
| | | ticipant | 4.2.6, |
| | | | Section |
| | | | 4.4.5 |
| | | | |
| names | String[Boolean] | TimeZoneRu | Section |
| | | le | 4.7.2 |
| | | | |
| nthOfPeriod | Int | NDay | Section |
| | | | 4.3.2 |
| | | | |
| offset | SignedDuration | OffsetTrig | Section |
| | | ger | 4.5.2 |
| | | | |
| offsetFrom | UTCDateTime | TimeZoneRu | Section |
| | | le | 4.7.2 |
| | | | |
| offsetTo | UTCDateTime | TimeZoneRu | Section |
| | | le | 4.7.2 |
| | | | |
| participants | Id[Participant] | JSEvent, | Section |
| | | JSTask | 4.4.5 |
| | | | |
| participation | String | Participan | Section |
| Comment | | t | 4.4.5 |
| | | | |
| participation | String | Participan | Section |
| Status | | t | 4.4.5 |
| | | | |
| percentComple | UnsignedInt | JSTask, Pa | Section |
| te | | rticipant | 5.2.4 |
| | | | |
| priority | Int | JSEvent, | Section |
| | | JSTask | 4.4.1 |
| | | | |
| privacy | String | JSEvent, | Section |
| | | JSTask | 4.4.3 |
| | | | |
| prodId | String | JSEvent, | Section |
| | | JSTask, | 4.1.4 |
| | | JSGroup | |
| | | | |
| progress | String | JSTask, Pa | Section |
| | | rticipant | 5.2.5 |
| | | | |
| progressUpdat | UTCDateTime | JSTask, Pa | Section |
| ed | | rticipant | 5.2.6 |
| | | | |
| recurrenceId | LocalDateTime | JSEvent, | Section |
| | | JSTask | 4.3.1 |
| | | | |
| recurrenceOve | LocalDateTime[PatchObject] | JSEvent, | Section |
| rrides | | JSTask, Ti | 4.3.4, |
| | | meZoneRule | Section |
| | | | 4.7.2 |
| | | | |
| recurrenceRul | RecurrenceRule[] | JSEvent, | Section |
| es | | JSTask, Ti | 4.3.2, |
| | | meZoneRule | Section |
| | | | 4.7.2 |
| | | | |
| rel | String | Link | Section |
| | | | 1.4.11 |
| | | | |
| relatedTo | String[Relation] | JSEvent, | Section |
| | | JSTask, | 4.1.3, |
| | | Alert | Section |
| | | | 4.5.2 |
| | | | |
| relation | String[Boolean] | Relation | Section |
| | | | 1.4.10 |
| | | | |
| relativeTo | String | OffsetTrig | Section |
| | | ger, | 4.5.2, |
| | | Location | Section |
| | | | 4.2.5 |
| | | | |
| replyTo | String[String] | JSEvent, | Section |
| | | JSTask | 4.4.4 |
| | | | |
| roles | String[Boolean] | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| rscale | String | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| standard | TimeZoneRule TimeZoneRule[] | TimeZone | Section |
| | | | 4.7.2 |
| | | | |
| start | LocalDateTime | TimeZoneRu | Section |
| | | le | 4.7.2 |
| | | | |
| scheduleAgent | String | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| scheduleForce | Boolean | Participan | Section |
| Send | | t | 4.4.5 |
| | | | |
| scheduleSeque | UnsignedInt | Participan | Section |
| nce | | t | 4.4.5 |
| | | | |
| scheduleStatu | String[] | Participan | Section |
| s | | t | 4.4.5 |
| | | | |
| scheduleUpdat | UTCDateTime | Participan | Section |
| ed | | t | 4.4.5 |
| | | | |
| sendTo | String[String] | Participan | Section |
| | | t | 4.4.5 |
| | | | |
| sequence | UnsignedInt | JSEvent, | Section |
| | | JSTask | 4.1.7 |
| | | | |
| showWithoutTi | Boolean | JSEvent, | Section |
| me | | JSTask | 4.2.4 |
| | | | |
| size | UnsignedInt | Link | Section |
| | | | 1.4.11 |
| | | | |
| skip | String | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| source | String | JSGroup | Section |
| | | | 5.3.2 |
| | | | |
| start | LocalDateTime | JSEvent, | Section |
| | | JSTask | 5.1.1, |
| | | | Section |
| | | | 5.2.2 |
| | | | |
| status | String | JSEvent | Section |
| | | | 5.1.3 |
| | | | |
| timeZone | TimeZoneId|null | JSEvent, | Section |
| | | JSTask, | 4.7.1, |
| | | Location | Section |
| | | | 4.2.5 |
| | | | |
| timeZones | TimeZoneId[TimeZone] | JSEvent, | Section |
| | | JSTask | 4.7.2 |
| | | | |
| title | String | JSEvent, | Section |
| | | JSTask, | 4.2.1 |
| | | JSGroup, | |
| | | Link | |
| | | | |
| trigger | OffsetTrigger|AbsoluteTrig | Alert | Section |
| | ger|UnknownTrigger | | 4.5.2 |
| | | | |
| tzId | String | TimeZone | Section |
| | | | 4.7.2 |
| | | | |
| uid | String | JSEvent, | Section |
| | | JSTask, | 4.1.2 |
| | | JSGroup | |
| | | | |
| until | LocalDateTime | Recurrence | Section |
| | | Rule | 4.3.2 |
| | | | |
| updated | UTCDateTime | JSEvent, | Section |
| | | JSTask, | 4.1.6 |
| | | JSGroup | |
| | | | |
| uri | String | VirtualLoc | Section |
| | | ation | 4.2.6 |
| | | | |
| url | String | TimeZone | Section |
| | | | 4.7.2 |
| | | | |
| useDefaultAle | Boolean | JSEvent, | Section |
| rts | | JSTask | 4.5.1 |
| | | | |
| validUntil | UTCDateTime | TimeZone | Section |
| | | | 4.7.2 |
| | | | |
| virtualLocati | Id[VirtualLocation] | JSEvent, | Section |
| ons | | JSTask | 4.2.6 |
| | | | |
| when | UTCDateTime | AbsoluteTr | Section |
| | | igger | 4.5.2 |
+---------------+----------------------------+------------+---------+
Table 1
8.3. Creation of "JSCalendar Types" Registry
The IANA will create 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
o Type Name: The name of the type.
o Reference or Description: A brief description or RFC number and
section reference where the Type is specified (may be omitted for
"reserved" type names).
o Intended Use: Common, reserved, or obsolete.
o Change Controller: Who may request a change to this entry's
definition ("IETF" for IETF-stream RFCs).
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 4.3.2 |
| | |
| Number | Section 1.3 |
| | |
| Participant | Section 4.4.5 |
| | |
| PatchObject | Section 1.4.9 |
| | |
| RecurrenceRule | Section 4.3.2 |
| | |
| 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
8.4. Creation of "JSCalendar Enum Values" Registry
The IANA will create 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 Property Template
This template is for adding a subregistry for a new enumerable
property to the JSCalendar Enum registry.
o Property Name: the name(s) of the property or properties where
these values may be used. This MUST be registered in the
JSCalendar Properties registry.
o Context: 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.
o Change Controller: ("IETF" for properties defined in IETF-stream
RFCs).
o Initial Contents: 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 Value Template
This template is for adding a new enum value to a subregistry in the
JSCalendar Enum registry.
o Enum Value: The verbatim value of the enum.
o 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
------------------------------------------------------------
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
------------------------------------------------------------
Property Name: freeBusyStatus
Context: JSEvent, JSTask
Change Controller: IETF
Initial Contents:
+------------+--------------------------+
| Enum Value | Reference or Description |
+------------+--------------------------+
| free | Section 4.4.2 |
| | |
| busy | Section 4.4.2 |
+------------+--------------------------+
Table 5
------------------------------------------------------------
Property Name: kind
Context: Participant
Change Controller: IETF
Initial Contents:
+------------+--------------------------+
| Enum Value | Reference or Description |
+------------+--------------------------+
| individual | Section 4.4.5 |
| | |
| group | Section 4.4.5 |
| | |
| resource | Section 4.4.5 |
| | |
| location | Section 4.4.5 |
+------------+--------------------------+
Table 6
------------------------------------------------------------
Property Name: participationStatus
Context: Participant
Change Controller: IETF
Initial Contents:
+--------------+--------------------------+
| Enum Value | Reference or Description |
+--------------+--------------------------+
| needs-action | Section 4.4.5 |
| | |
| accepted | Section 4.4.5 |
| | |
| declined | Section 4.4.5 |
| | |
| tenative tentative | Section 4.4.5 |
| | |
| delegated | Section 4.4.5 |
+--------------+--------------------------+
Table 7
------------------------------------------------------------
Property Name: privacy
Context: JSEvent, JSTask
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 8
------------------------------------------------------------
Property Name: progress
Context: JSTask, 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 9
------------------------------------------------------------
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 10
------------------------------------------------------------
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 11
------------------------------------------------------------
Property Name: roles
Context: Participant
Change Controller: IETF
Initial Contents:
+---------------+--------------------------+
| Enum Value | Reference or Description |
+---------------+--------------------------+
| owner | Section 4.4.5 |
| | |
| attendee | Section 4.4.5 |
| | |
| optional | Section 4.4.5 |
| | |
| informational | Section 4.4.5 |
| | |
| chair | Section 4.4.5 |
| | |
| contact | Section 4.4.5 |
+---------------+--------------------------+
Table 12
------------------------------------------------------------
Property Name: scheduleAgent
Context: Participant
Change Controller: IETF
Initial Contents:
+------------+--------------------------+
| Enum Value | Reference or Description |
+------------+--------------------------+
| server | Section 4.4.5 |
| | |
| client | Section 4.4.5 |
| | |
| none | Section 4.4.5 |
+------------+--------------------------+
Table 13
------------------------------------------------------------
Property Name: status
Context: JSEvent
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 14
9. 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.
10. References
10.1. Normative References
[CLDR] "Unicode Common Locale Data Repository",
<http://cldr.unicode.org/>.
[COLORS] "CSS Color Module", <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>.
[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>.
10.2. Informative References
[LINKRELS]
"IANA Link Relation Types",
<https://www.iana.org/assignments/link-relations/link-
relations.xhtml>.
[LOCATIONTYPES]
"IANA Location Types Registry",
<https://www.iana.org/assignments/location-type-registry/
location-type-registry.xhtml>.
[MEDIATYPES]
"IANA Media Types", <https://www.iana.org/assignments/
media-types/media-types.xhtml>.
[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>.
Authors' Addresses
Neil Jenkins
Fastmail
PO Box 234
Collins St West
Melbourne VIC 8007
Australia
Email: neilj@fastmailteam.com
URI: https://www.fastmail.com
Robert Stepanek
Fastmail
PO Box 234
Collins St West
Melbourne VIC 8007
Australia
Email: rsto@fastmailteam.com
URI: https://www.fastmail.com