Internet DRAFT - draft-jenkins-jscalendar
draft-jenkins-jscalendar
Calendaring extensions N. Jenkins
Internet-Draft R. Stepanek
Intended status: Standards Track FastMail
Expires: July 23, 2018 January 19, 2018
JSCalendar: A JSON representation of calendar data
draft-jenkins-jscalendar-05
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
to the widely deployed iCalendar data format and to be unambiguous,
extendable and simple to process.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on July 23, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Relation to the iCalendar format . . . . . . . . . . . . 4
1.2. Notational Conventions . . . . . . . . . . . . . . . . . 5
2. JSCalendar objects . . . . . . . . . . . . . . . . . . . . . 5
2.1. JSEvent . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. JSTask . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3. JSGroup . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Structure of JSCalendar objects . . . . . . . . . . . . . . . 6
3.1. Type signatures . . . . . . . . . . . . . . . . . . . . . 6
3.2. Data Types . . . . . . . . . . . . . . . . . . . . . . . 6
3.2.1. UTCDate . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.2. LocalDate . . . . . . . . . . . . . . . . . . . . . . 7
3.2.3. Duration . . . . . . . . . . . . . . . . . . . . . . 7
3.2.4. PatchObject . . . . . . . . . . . . . . . . . . . . . 7
3.2.5. Normalisation and equivalence . . . . . . . . . . . . 8
3.3. Custom property extensions and values . . . . . . . . . . 9
4. Common JSCalendar properties . . . . . . . . . . . . . . . . 9
4.1. Metadata properties . . . . . . . . . . . . . . . . . . . 9
4.1.1. @type . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.2. uid . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1.3. relatedTo . . . . . . . . . . . . . . . . . . . . . . 10
4.1.4. prodId . . . . . . . . . . . . . . . . . . . . . . . 11
4.1.5. created . . . . . . . . . . . . . . . . . . . . . . . 11
4.1.6. updated . . . . . . . . . . . . . . . . . . . . . . . 11
4.1.7. sequence . . . . . . . . . . . . . . . . . . . . . . 11
4.1.8. method . . . . . . . . . . . . . . . . . . . . . . . 11
4.2. What and where properties . . . . . . . . . . . . . . . . 11
4.2.1. title . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2.2. description . . . . . . . . . . . . . . . . . . . . . 12
4.2.3. htmlDescription . . . . . . . . . . . . . . . . . . . 12
4.2.4. locations . . . . . . . . . . . . . . . . . . . . . . 12
4.2.5. links . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2.6. locale . . . . . . . . . . . . . . . . . . . . . . . 15
4.2.7. keywords . . . . . . . . . . . . . . . . . . . . . . 15
4.2.8. categories . . . . . . . . . . . . . . . . . . . . . 16
4.2.9. color . . . . . . . . . . . . . . . . . . . . . . . . 16
4.3. Recurrence properties . . . . . . . . . . . . . . . . . . 16
4.3.1. recurrenceRule . . . . . . . . . . . . . . . . . . . 16
4.3.2. recurrenceOverrides . . . . . . . . . . . . . . . . . 18
4.4. Sharing and scheduling properties . . . . . . . . . . . . 19
4.4.1. priority . . . . . . . . . . . . . . . . . . . . . . 19
4.4.2. freeBusyStatus . . . . . . . . . . . . . . . . . . . 19
4.4.3. privacy . . . . . . . . . . . . . . . . . . . . . . . 19
4.4.4. replyTo . . . . . . . . . . . . . . . . . . . . . . . 21
4.4.5. participants . . . . . . . . . . . . . . . . . . . . 22
4.5. Alerts properties . . . . . . . . . . . . . . . . . . . . 24
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4.5.1. useDefaultAlerts . . . . . . . . . . . . . . . . . . 25
4.5.2. alerts . . . . . . . . . . . . . . . . . . . . . . . 25
4.6. Multilingual properties . . . . . . . . . . . . . . . . . 28
4.6.1. localizations . . . . . . . . . . . . . . . . . . . . 28
5. Type-specific JSCalendar properties . . . . . . . . . . . . . 28
5.1. JSEvent properties . . . . . . . . . . . . . . . . . . . 28
5.1.1. start . . . . . . . . . . . . . . . . . . . . . . . . 29
5.1.2. timeZone . . . . . . . . . . . . . . . . . . . . . . 29
5.1.3. duration . . . . . . . . . . . . . . . . . . . . . . 29
5.1.4. isAllDay . . . . . . . . . . . . . . . . . . . . . . 29
5.1.5. status . . . . . . . . . . . . . . . . . . . . . . . 30
5.2. JSTask properties . . . . . . . . . . . . . . . . . . . . 30
5.2.1. due . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.2.2. start . . . . . . . . . . . . . . . . . . . . . . . . 30
5.2.3. timeZone . . . . . . . . . . . . . . . . . . . . . . 30
5.2.4. estimatedDuration . . . . . . . . . . . . . . . . . . 30
5.2.5. completed . . . . . . . . . . . . . . . . . . . . . . 31
5.2.6. isAllDay . . . . . . . . . . . . . . . . . . . . . . 31
5.2.7. progress . . . . . . . . . . . . . . . . . . . . . . 31
5.2.8. status . . . . . . . . . . . . . . . . . . . . . . . 32
5.3. JSGroup properties . . . . . . . . . . . . . . . . . . . 32
5.3.1. entries . . . . . . . . . . . . . . . . . . . . . . . 33
5.3.2. source . . . . . . . . . . . . . . . . . . . . . . . 33
6. Conversion from and to iCalendar . . . . . . . . . . . . . . 33
6.1. JSEvent . . . . . . . . . . . . . . . . . . . . . . . . . 33
6.2. JSTask . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.3. JSGroup . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.4. Common properties . . . . . . . . . . . . . . . . . . . . 36
6.5. Locations and participants . . . . . . . . . . . . . . . 38
6.6. Unknown properties . . . . . . . . . . . . . . . . . . . 40
7. JSCalendar object examples . . . . . . . . . . . . . . . . . 40
7.1. Simple event . . . . . . . . . . . . . . . . . . . . . . 40
7.2. Simple task . . . . . . . . . . . . . . . . . . . . . . . 41
7.3. Simple group . . . . . . . . . . . . . . . . . . . . . . 41
7.4. All-day event . . . . . . . . . . . . . . . . . . . . . . 42
7.5. Task with a due date . . . . . . . . . . . . . . . . . . 42
7.6. Event with end time-zone . . . . . . . . . . . . . . . . 43
7.7. Floating-time event (with recurrence) . . . . . . . . . . 43
7.8. Event with multiple locations and localization . . . . . 44
7.9. Recurring event with overrides . . . . . . . . . . . . . 45
7.10. Recurring event with participants . . . . . . . . . . . . 45
8. Security Considerations . . . . . . . . . . . . . . . . . . . 47
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 47
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 47
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 47
11.1. Normative References . . . . . . . . . . . . . . . . . . 47
11.2. Informative References . . . . . . . . . . . . . . . . . 50
11.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 50
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Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 50
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. It 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 a simple key-value pair, reducing complexity of its
representation.
o The data model should avoid all ambiguities and make it difficult
to make mistakes during implementation.
o Most of the initial set of attributes should be taken from the
iCalendar data format ([RFC5545], also see Section 1.1), but the
specification should add new attributes or value types, or not
support existing ones, where appropriate. Conversion between the
data formats need not fully preserve semantic meaning.
o Extensions, such as new properties and components, MUST NOT lead
to requiring an update 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 mostly is a
pragmatic choice: its widespread use should help to speed up
JSCalendar adoption and a wide range of production-ready JSON
implementations allows to decrease interoperability issues.
1.1. Relation to the iCalendar format
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.
For example, iCalendar defines various formats for local times, UTC
time and dates, which confuses new users. Other sources for errors
are the requirement for custom time-zone definitions within a single
calendar component, as well as the iCalendar format itself; the
latter causing interoperability issues due to misuse of CR LF
terminated strings, line continuations and subtle differences between
iCalendar parsers. Lastly, up until recently the iCalendar format
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did not allow to express the difference between two calendar
components, which results in verbose exchanges during scheduling.
Some of these issues were addressed by the jCal [RFC7265] format,
which is a direct mapping between iCalendar and JSON. However, it
did not attempt to extend or update iCalendar semantics.
1.2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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.
2. JSCalendar objects
This section describes the calendar object types specified by
JSCalendar.
2.1. JSEvent
MIME type: "application/calendar+json;type=jsevent"
A JSEvent represents a scheduled amount of time on a calendar,
typically a meeting, appointment, reminder or anniversary. Multiple
participants may partake in the event at multiple locations.
The @type (Section 4.1.1) property value MUST be "jsevent".
2.2. JSTask
MIME type: "application/calendar+json;type=jstask"
A JSTask represents an action-item, assignment, to-do or work item .
The @type (Section 4.1.1) property value MUST be "jstask".
A JSTask may start and be due at certain points in time, may take
some estimated time to complete and may recur; none of which is
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required. This notably differs from JSEvent (Section 2.1) which is
required to start at a certain point in time and typically takes some
non-zero duration to complete.
2.3. JSGroup
MIME type: "application/calendar+json;type=jsgroup"
A JSGroup is a collection of JSEvent (Section 2.1) and 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".
3. Structure of JSCalendar objects
A JSCalendar object is a JSON object, which MUST be valid I-JSON (a
stricter subset of JSON), as specified in [RFC8259]. Property names
and values are case-sensitive.
The object has a collection of properties, as specified in the
following sections. Unless otherwise specified, all properties are
optional; omitted properties MUST be treated identically to if that
property had the value of "null", unless otherwise specified.
3.1. Type signatures
Types signatures are given for all JSON objects in this document.
The following conventions are used:
o "Boolean|String": The value is either a JSON "Boolean" value, or a
JSON "String" value.
o "Foo": Any name that is not a native JSON type means an object for
which the properties (and their types) are defined elsewhere
within this document.
o "Foo[]": An array of objects of type "Foo".
o "String[Foo]": A JSON "Object" being used as a map (associative
array), where all the values are of type "Foo".
3.2. Data Types
In addition to the standard JSON data types, the following data types
are used in this specification:
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3.2.1. UTCDate
This is a string in [RFC3339] "date-time" format, with the further
restrictions that any letters MUST be in upper-case, the time
component MUST be included and the time MUST be in UTC. 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 OK, but
"2010-10-10T10:10:10.000Z" is invalid and MUST be encoded as
"2010-10-10T10:10:10Z".
In common notation, it should be of the form "YYYY-MM-DDTHH:MM:SSZ".
3.2.2. LocalDate
This is a date-time string _with no time-zone/offset information_.
It is otherwise in the same format as UTCDate: "YYYY-MM-DDTHH:MM:SS".
The time-zone to associate the LocalDate with comes from an
associated property, or if no time-zone is associated it defines
_floating time_. Floating date-times are not tied to any specific
time-zone. Instead, they occur in every timezone at the same _wall-
clock_ time (as opposed to the same instant point in time).
3.2.3. Duration
A duration is represented by a subset of ISO8601 duration format, as
specified by the following ABNF:
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"
duration = "P" (dur-day [dur-time] / dur-time)
In addition, the duration MUST NOT include fractional second values
unless the fraction is non-zero. A zero duration MUST be represented
as "P0D".
3.2.4. PatchObject
A *PatchObject* is of type "String[*|null]", and represents an
unordered set of patches on a JSON object. The keys are a path in a
subset of [RFC6901] JSON pointer format, with an implicit leading "/"
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(i.e. prefix each key 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. it MUST NOT
insert/delete from an array; the array MUST be replaced in its
entirety instead).
2. When evaluating a path, all parts prior to the last (i.e. the
value after the final slash) MUST exist.
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".
The value associated with each pointer is either:
o "null": Remove the property from the patched object. If not
present in the parent, this a no-op.
o Anything else: The value to replace the inherited property on the
patch object with (if present) or add to the property (if not
present).
Implementations MUST reject a PatchObject if any of its patches are
invalid.
3.2.5. Normalisation and equivalence
JSCalendar aims to provide unambiguous definitions for value types
and properties, but does not define a general normalisation 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 (for
example, the CalDAV protocol [RFC4791] requires octet equivalence of
the encoded calendar object to determine ETag equivalence).
Normalisation 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.
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o Several JSCalendar property values are defined as URIs and MIME
types, but normalisation 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 normalisation is
left to client and server implementations and to be negotiated by a
calendar exchange protocol or defined by another RFC.
3.3. Custom property extensions and values
Vendors MAY add additional properties to the calendar object to
support their custom features. The names of these properties MUST be
prefixed with a domain name controlled by the vendor to avoid
conflict, e.g. "example.com/customprop".
Some JSCalendar properties allow vendor-specific value extensions.
If so, vendor specific values MUST be prefixed with a domain name
controlled by the vendor, e.g. "example.com/customrel", unless
otherwise noted.
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 Section 5 describe the set of supported properties per type.
4.1. Metadata properties
4.1.1. @type
Type: "String"
Specifies the type which this object represents. This MUST be one of
the following values, registered in a future RFC, or a vendor-
specific value:
o "jsevent": a JSCalendar event (Section 2.1).
o "jstask": a JSCalendar task (Section 2.2).
o "jsgroup": a JSCalendar group (Section 2.3).
A valid JSCalendar object MUST include this property.
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4.1.2. uid
Type: "String"
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), and the random or pseudo-random version is recommended to
use.
A valid JSCalendar object MUST include this property.
4.1.3. relatedTo
Type: "String[Relation]|null"
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.
A *Relation* object has the following properties:
o *relation*: "String[]" Describes how the linked object is related
to this object.
The strings in the array MUST each be at most one of the following
values, registered in a future RFC, or a vendor-specific value:
* "first": The linked object is the first in the series this
object is part of.
* "next": The linked object is the next in the series this object
is part of.
* "child": The linked object is a subpart of this object.
* "parent": This object is part of the overall linked object.
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 objects after the split. A "relation=["next"]"
relatedTo property MUST be set on the original object with the uid of
the new object. A "relation=["first"]" relatedTo property with the
UID of the first object in the series MUST be set on the new object.
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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|null"
The identifier for the product that created the JSCalendar object.
The vendor of the implementation SHOULD 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 an
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.
4.1.5. created
Type: "UTCDate|null"
The date and time this object was initially created.
4.1.6. updated
Type: "UTCDate"
The date and time the data in this object was last modified.
4.1.7. sequence
Type: "Number" (Defaults to "0" if omitted)
Initially zero, this MUST be a non-negative integer that is
monotonically incremented each time a change is made to the object.
4.1.8. method
Type: "String|null"
The iTIP ([RFC5546]) method, in lower-case. Used for scheduling.
4.2. What and where properties
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4.2.1. title
Type: "String" (Defaults to the empty string if omitted)
A short summary of the object.
4.2.2. description
Type: "String" (Defaults to the empty string if omitted)
A longer form description of the object. This is plain text, but a
client SHOULD attempt to hyperlink URLs when displaying it.
4.2.3. htmlDescription
Type: "String" (Defaults to the empty string if omitted)
A longer form rich-text description of the object. This is HTML text
[1] and allows to reference resources in the *links* property by use
of CID URLs (see [RFC2392]). To convert a CID URL to the *cid*
property value of a *Link* object, implementations MUST follow the
conversion described in section 2 of [RFC2392]. Implementations MAY
choose not to follow untrusted external CID URLs referenced in the
*links* property, in which case they MUST treat the *htmlDescription*
property as if omitted. Implementations MUST preserve the value of
this property, even if it contains untrusted links.
4.2.4. locations
Type: "String[Location]|null"
A map of location ids to Location objects, representing locations
associated with the object. A location id may be any string and need
only be unique to this object, although a UUID is a practical choice.
A *Location* object has the following properties. All properties are
optional, but every Location object MUST have at least one property:
o *name*: "String" The human-readable name of the location.
o *description*: "String" Human-readable instructions for accessing
this location. This may be an address, set of directions, door
access code, etc.
o *rel*: "String" The relation type of this location to the
JSCalendar object.
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This MUST be either one of the following values, registered in a
future RFC, or a vendor-specific value. Any value the client or
server doesn't understand should be treated the same as "unknown".
* "start": The JSCalendar object starts at this location.
* "end": The JSCalendar object ends at this location.
* "virtual": This is not a physical location (e.g. this location
is an online chat room where people will meet).
* "unknown": The relation of this location to the calendar object
is unknown.
o *features*: "String[]|null" The features supported by this
location.
The strings in the array MUST each be either one of the following
values, registered in a future RFC, or a vendor-specific value.
Any value the client or server doesn't understand should be
ignored, but preserved.
The features supported by locations with rel-type "virtual" are:
* "audio": audio conferencing
* "chat": chat or instant messaging
* "screen": screen sharing
* "video": video conferencing
* any vendor-prefixed custom value
o *timeZone*: "String|null" (Defaults to "null" if omitted) A time-
zone for this location.
If "null", the *timeZone* from the JSCalendar object MUST be
presumed when a time-zone is needed in relation to this location.
o *coordinates*: "String" An [RFC5870] "geo:" URI for the location.
o *uri*: "String" A URI that represents how to connect to this
location.
This may be a telephone number (represented as
"tel:+1-555-555-555") for a teleconference, a web address for
online chat, or any custom URI.
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o *linkIds*: "String[]|null" A list of ids for links to alternate
representations of this location.
For example, an alternative representation could be in vCard
format. If a given value does not correspond to any link id in
the links property of the instance, this MUST be ignored.
4.2.5. links
Type: "String[Link]|null"
A map of link ids to Link objects, representing external resources
associated with the object. A link id may be any string and need
only be unique to this object, although the href or a UUID are
practical choices.
A *Link* object has the following properties:
o *href*: "String" A URI from which the resource may be fetched.
This MAY be a "data:" URL, but it is recommended that the file be
hosted on a server to avoid embedding arbitrary large data in
JSCalendar object instances.
o *cid* "String|null" The id used within the *htmlDescription*
property to reference this link.
If not null, this MUST be a valid Content-ID MIME header value
(see [RFC2392]). The identifier MUST be unique within this
JSCalendar object but has no meaning beyond that. Specifically,
it MAY be different from the *Link* object identifier in the
enclosing *links* property.
o *type*: "String|null"(optional, defaults to "null") The content-
type [RFC6838] of the resource, if known.
o *size*: "Number|null"(optional, defaults to "null") The size, in
bytes, of the resource when fully decoded (i.e. the number of
bytes in the file the user would download), if known.
o *rel*: "String"(optional, defaults to "related") Identifies the
relation of the linked resource to the object. The value MUST be
a registered relation type (see [RFC8288] and IANA Link Relations
[2]).
Links with a rel of "enclosure" SHOULD be considered by the client
as attachments for download.
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Links with a rel of "describedby" SHOULD be considered by the
client to be an alternate representation of the description and
HTML description.
Links with a rel of "icon" SHOULD be considered by the client to
be an image that it MAY use when presenting the calendar data to a
user. The *properties* object of this link MAY include a
"display" property indicating the intended purpose of this image.
If included, the value MUST be either one of the following values,
registered in a future RFC, or a vendor-specific value.
* "badge": an image inline with 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|null"(optional, defaults to "null") A human-
readable description of the resource.
o *properties*: "String[String|null]|null"(optional, defaults to
"null") Extra metadata submitted by clients about a link. Server
implementations MUST preserve these properties.
The keys are as defined in this document, as defined in a future
RFC, or URIs that should be owned by the client author to avoid
conflicts.
4.2.6. locale
Type: "String|null"
The [RFC5646] language tag that best describes the locale used for
the calendar object, if known.
4.2.7. keywords
Type: "String[]|null"
A list of keywords or tags related to the object. The values are
free-form and do not have to follow any particular structure.
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4.2.8. categories
Type: "String[]|null"
Specifies the categories related to the calendar object. Array
values MUST be URIs. 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".
4.2.9. color
Type: "String|null"
Specifies a color clients MAY use when displaying this calendar
object. The value is a case-insensitive color name taken from the
CSS3 set of names, defined in Section 4.3 of W3C.REC-
css3-color-20110607 [3] or a CSS3 RGB color hex value.
4.3. Recurrence properties
4.3.1. recurrenceRule
Type: "Recurrence"
Defines a recurrence rule (repeating pattern) for recurring calendar
objects.
A *Recurrence* object is a JSON object mapping of a RECUR value type
in iCalendar, see [RFC5545] and[RFC7529]. Objects recur by applying
the recurrence rule (and *recurrenceOverrides*) to the *start* date/
time. A JSTask (Section 2.2) without a *start* property value recurs
by its *due* date/time, if defined.
A Recurrence object has the following properties:
o *frequency*: "String" This MUST be one of the following values:
* "yearly"
* "monthly"
* "weekly"
* "daily"
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* "hourly"
* "minutely"
* "secondly"
To convert from iCalendar, simply lower-case the FREQ part.
o *interval*: "Number"(optional, defaults to "1") The INTERVAL part
from iCal. If included, it MUST be an integer "x >= 1".
o *rscale*: "String"(optional, defaults to ""gregorian"") The RSCALE
part from iCalendar RSCALE [RFC7529], converted to lower-case.
o *skip*: "String"(optional, defaults to ""omit"") The SKIP part
from iCalendar RSCALE [RFC7529], converted to lower-case.
o *firstDayOfWeek*: "String"(optional, defaults to ""mo"") The WKST
part from iCalendar, represented as a lower-case 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"".
o *byDay*: "NDay[]"(optional) An *NDay* object has the following
properties:
* *day*: "String" The day-of-the-week part of the BYDAY value in
iCalendar, lower-cased. MUST be one of the following values:
""mo"|"tu"|"we"|"th"|"fr"|"sa"|"su"".
* *nthOfPeriod*: "Number"(optional) The optional ordinal part of
the BYDAY value in iCalendar (e.g. ""+1"" or ""-3""). If
present, rather than representing every occurrence of the
weekday defined in the *day* property of this *NDay*, 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.
o *byMonthDay*: "Number[]"(optional) The BYMONTHDAY part from
iCalendar. The array MUST have at least one entry if included.
o *byMonth*: "String[]"(optional) The BYMONTH part from iCalendar.
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 Gregorian calendar), with an optional ""L""
suffix (see [RFC7529]) for leap months (this MUST be upper-case,
e.g. ""3L""). The array MUST have at least one entry if included.
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o *byYearDay*: "Number[]"(optional) The BYYEARDAY part from
iCalendar. The array MUST have at least one entry if included.
o *byWeekNo*: "Number[]"(optional) The BYWEEKNO part from iCalendar.
The array MUST have at least one entry if included.
o *byHour*: "Number[]"(optional) The BYHOUR part from iCalendar.
The array MUST have at least one entry if included.
o *byMinute*: "Number[]"(optional) The BYMINUTE part from iCalendar.
The array MUST have at least one entry if included.
o *bySecond*: "Number[]"(optional) The BYSECOND part from iCalendar.
The array MUST have at least one entry if included.
o *count*: "Number"(optional) The COUNT part from iCalendar. This
MUST NOT be included if an *until* property is specified.
o *until*: "LocalDate"(optional) The UNTIL part from iCalendar.
This MUST NOT be included if a *count* property is specified.
Note, as in iCalendar, this date is presumed to be in the time-
zone specified in *timeZone*. It is not a UTC time.
4.3.2. recurrenceOverrides
Type: "LocalDate[PatchObject|null]|null"
A map of the recurrence-ids (the date-time of the start of the
occurrence) to either "null", to indicate the occurrence should be
deleted, or an object of patches to apply to the generated occurrence
object.
If the recurrence-id does not match an expanded start date from a
recurrence rule, it is to be treated as an additional occurrence
(like an RDATE from iCalendar). The patch object may often be empty
in this case.
By default, an occurrence inherits all properties from the main
object except the start (or due) date-time, which is shifted to the
new start time. However, individual properties of the occurrence can
be modified by a patch, or multiple patches.
A pointer in the PatchObject MUST NOT start with one of the following
prefixes; any patch with such a key MUST be ignored:
o @type
o uid
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o relatedTo
o prodId
o method
o isAllDay
o recurrenceRule
o recurrenceOverrides
o replyTo
4.4. Sharing and scheduling properties
4.4.1. priority
Type: "Number"(defaults to "0" if omitted)
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. 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"(defaults to "busy" if omitted)
Specifies how this property should be treated when calculating free-
busy state. The value MUST be one of:
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"(defaults to "public" if omitted)
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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
implementations.
This property MUST NOT affect the information sent to scheduled
participants; it is only interpreted when the object is shared as
part of a shared calendar.
The value MUST be either one of the following values, registered in a
future RFC, or a vendor-specific value. Vendor specific values MUST
be prefixed with a domain name controlled by the vendor, e.g.
"example.com/topsecret". 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. Implementations MUST ensure the
following properties are stripped when the object is accessed by a
sharee:
* title
* description
* htmlDescription
* locations
* links
* locale
* localizations
* participants
* replyTo
In addition, any patches in "recurrenceOverrides" whose key is
prefixed with one of the above properties MUST be stripped.
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o "secret": The object is hidden completely (as though it did not
exist) when the calendar is shared.
4.4.4. replyTo
Type: "String[String]|null"
Represents methods by which a participant may RSVP to the organizer
of the calendar object. The keys in the property value are the
available methods. The value is a URI to use that method. Future
methods may be defined in future specifications; a calendar client
MUST ignore any method it does not understand.
The following methods are defined:
o "imip": The organizer accepts an iMIP [RFC6047] response. The
value MUST be a "mailto:" URI.
o "web": There is a web page where the user may submit an RSVP using
their browser. The value MUST be an "http:" or "https:" URI
Template ([RFC6570]) in level 1 format. The template MAY contain
variables that MUST be expanded from the JSCalendar object as
defined in table Table 1. Calendar clients SHOULD be prepared to
handle authentication requests from the respective web page and
for the participant email, but this specification does not mandate
any specific mechanism.
+--------------+----------------------------------------------------+
| Variable | Expand to |
+--------------+----------------------------------------------------+
| email | The *email* property value of the replying |
| | *Participant* object. |
| | |
| uid | The *uid* property value of the JSCalendar object. |
| | |
| sequence | The *sequence* property value of the JSCalendar |
| | object. |
| | |
| recurrenceId | The recurrence-id when replying for a single |
| | occurrence of a recurring JSCalendar object. The |
| | value is the date-time of the non-overridden start |
| | as determined by expanding the *recurrenceRule* of |
| | the JSCalendar object. |
+--------------+----------------------------------------------------+
Table 1: replyTo URI Template variables
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4.4.5. participants
Type: "String[Participant]|null"
A map of participant ids to participants, describing their
participation in the calendar object. A participant id may be any
string and need only be unique to this calendar object; the email
address of the participant is a good choice.
A *Participant* object has the following properties. Properties are
mandatory unless marked otherwise:
o *name*: "String" The display name of the participant (e.g. "Joe
Bloggs").
o *email*: "String" The email address for the participant.
o *kind*: "String"(optional, defaults to "unknown") What kind of
entity this participant is.
This MUST be either one of the following values, registered in a
future RFC, or a vendor-specific value. Any value the client or
server doesn't understand should be treated the same as "unknown".
* "individual": a single person
* "group": a collection of people invited as a whole
* "resource": a non-human resource, e.g. a projector
* "location": a physical location involved in the calendar object
that needs to be scheduled, e.g. a conference room.
* "unknown": no information is available about the kind of this
participant.
o *roles*: "String[]" A list of roles that this participant fulfils.
At least one value MUST be specified for the participant. This
MUST be either one of the following values, registered in a future
RFC, or a vendor-specific value. Any value the client or server
doesn't understand should be preserved but ignored.
* "owner": The participant is an owner of the object, and allowed
to make alterations to any part of it.
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* "attendee": The participant is an attendee of the calendar
object. Attendees are only allowed to alter their own
participation.
* "chair": The participant is in charge of the calendar object
when it occurs.
o *locationId*: "String|null"(optional, defaults to "null") 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 instance, this MUST be treated the same
as if the participant's locationId were specified as null.
o *rsvpResponse*: "String"(optional, defaults to "needs-action") The
RSVP response, if any, of this participant.
The value MUST be either one of the following values, registered
in a future RFC, or a vendor-specific value:
* "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.
o *participation*: "String"(optional, defaults to "required") The
required participation of this participant.
The value MUST be either one of the following values, registered
in a future RFC, or a vendor-specific value. Any value the client
or server doesn't understand should be treated the same as
"required".
* "non-participant": Indicates a participant who is copied for
information purposes only.
* "optional": Indicates a participant whose participation is
optional.
* "required": Indicates a participant whose participation is
required.
o *rsvpWanted*: "Boolean"(optional, defaults to "false") If true,
the organizer is expecting the participant to notify them of their
status.
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o *scheduleSequence*: "Number"(optional, defaults to "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 partcipant has sent a
new RSVP 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 *scheduleUpdated*: "UTCDate|null"(optional, defaults to "null")
The *updated* property of the last iMIP response from the
participant.
This can be compared to the *updated* timestamp in future iMIP
responses to determine if the response is older or newer than the
current data.
o *invitedBy*: "String|null"(optional, defaults to "null") The
participant id of the participant who invited this one, if known.
o *delegatedTo*: "String[]|null"(optional, defaults to "null") A
list of participant ids of participants that this participant has
delegated their participation to. This MUST be omitted if none
(rather than an empty array).
o *delegatedFrom*: "String[]|null"(optional, defaults to "null") A
list of participant ids that this participant is acting as a
delegate for. This MUST be omitted if none (rather than an empty
array).
o *memberOf*: "String[]|null"(optional, defaults to "null") A list
of group participants that were invited to this calendar object,
which caused this participant to be invited due to their
membership of the group(s). This MUST be omitted if none (rather
than an empty array).
o *linkIds*: "String[]|null"(optional, defaults to "null") Links to
more information about this participant, for example in vCard
format. If a given value does not correspond to any link id in
the links property of the instance, this id MUST be ignored. This
MUST be omitted if none (rather than an empty array).
4.5. Alerts properties
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4.5.1. useDefaultAlerts
Type: "Boolean" (defaults to "false" if omitted)
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: "String[Alert]|null"
A map of alert ids to Alert objects, representing alerts/reminders to
display or send the user for this calendar object. An alert id may
be any string and need only be unique to this calendar object,
although a globally unique id is a practical choice (also see
Section 4.1.2)).
An *Alert* Object has the following properties:
o *relativeTo*: "String" (optional, defaults to "before-start")
Specifies where the offset is relative to for the alarm to
trigger. The value MUST be one of:
* "before-start"
* "after-start"
* "before-end"
* "after-end"
o *offset*: "Duration" The offset from the start and end/due of the
calendar object to fire the alert. If the calendar object does
not define a time-zone, the user's default time-zone SHOULD be
used when determining the offset, if known. Otherwise, the time-
zone to use is implementation specific.
o *action*: "DisplayAction|EmailAction|UnknownAction"
Describes how to alert the user.
A *DisplayAction* means a message (which is service dependent, but
SHOULD include the title and start or due time of the calendar
object) SHOULD be shown to the user on any client connected to
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this account at the specified time. How this message is formatted
(and any sound or other method of drawing the user's attention) is
client specific. It has the following properties:
* *type*: "String" The value MUST be "display".
* *acknowledged*: "UTCDate|null " (optional)
When the user has permanently dismissed the alert the client
MUST set this to the current time in UTC. Other clients which
sync this property can then 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, the *acknowledged* property of
the parent object MUST be updated, unless the alert is already
overridden in *recurrenceOverrides*.
* *snoozed*: "UTCDate|null" (optional)
If the user temporarily dismisses the alert, this is the UTC
date-time after which it should be reshown. Clients displaying
this alert SHOULD hide it if the snoozed property is updated to
a time in the future. When that time is reached, the alert
SHOULD be reshown unless acknowledged is now after the original
trigger time.
Setting this property on an instance of a recurring calendar
object MUST update the alarm on the master object, unless the
respective instance already is defined in
"recurrenceOverrides". It MUST NOT generate an override for
the sole use of snoozing an alarm.
* *mediaLinkIds*: "String[]|null " (optional)
A list of link identifiers in the JSCalendar object *links*
property. Clients SHOULD play one or more of the link contents
that are supported by the client implementation and are
appropriate for the given device and user context.
An *EmailAction* means an email SHOULD be sent as specified in the
object at the specified time. It has the following properties:
* *type*: "String" The value MUST be "email".
* *to*: "Emailer[]" An array of name/email objects to send the
alert to.
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An *Emailer* object has the following properties:
+ name: String The name of the recipient. If not known,
clients SHOULD use the empty string.
+ email: String The email address of the recipient.
* *subject*: "String" (optional) The subject to use for the
email. If omitted, this is implementation specific, but the
server SHOULD try to choose an appropriate subject, e.g. by
including the summary.
* *textBody*: "String" (optional) The plain-text body to use for
the email. If omitted, the body of the email is implementation
specific, but the server SHOULD include all pertinent details
about the calendar object, such as summary, location and start
time.
* *htmlBody*: "String" (optional) The HTML body to use for the
email, with rich-media content processed as for the
*htmlDescription* property of the JSCalendar object (see
Section 4.2.3), e.g. all CID URLs MUST be embedded in the
generated alert email HTML body, or the *htmlBody* property
ignored completely. If the textBody property of this alert
action is not set, the server SHOULD generate a plain-text
version from the HTML body and include it in a "multipart/
alternative" MIME message.
* *attachments*: "String[]|null" (optional) A list of link
identifiers in the JSCalendar object links property. Included
attachments SHOULD be embedded in the MIME message with the
"Content-Disposition" header value set to "attachment" (see
[RFC2183]). Implementations MAY refuse to include one or more
attachments when building an alert email, in which case they
MUST ignore the contents of the *attachments* property (e.g.
they MUST NOT include a subset of attachments).
An *UnknownAction* object is an object that contains a *type *
property whose value is not "email" or "string", plus zero or more
other properties. This is for compatibility with client
extensions and future RFCs. The client or server SHOULD NOT
trigger any type of alert for action types they do not understand,
but MUST preserve them.
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4.6. Multilingual properties
4.6.1. localizations
Type: "String[PatchObject]|null"
A map of [RFC5646] language tags to patch objects, which localise the
calendar object into the locale of the respective language tag.
See the description of PatchObject (Section 3.2.4) for the structure
of the PatchObject. The patches are applied to the top-level object
and MUST only patch the following properties:
o title
o description
o htmlDescription
o keywords
o Location name
o Location description
o Link title
o EmailAction alert subject
o EmailAction alert textBody
o EmailAction alert htmlBody
o any Link properties entry except the "display" field
o any UnknownAction alert property except the "type" field
o any unknown or vendor-specific property (if not defined otherwise
in a future RFC or vendor-specific extension).
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:
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5.1.1. start
Type: "LocalDate" e.g. "2015-09-02T00:00:00"
The date/time the event would start in the event's time-zone.
A valid JSEvent MUST include this property.
5.1.2. timeZone
Type: "String|null"
The IANA Time Zone Database [4] name for the time-zone the event is
scheduled in, or "null" for floating time. If omitted, this MUST be
presumed to be "null" (i.e. floating time).
5.1.3. duration
Type: "Duration", e.g. "P2DT3H" (Defaults to "P0D" if omitted)
The zero or positive duration of the event in absolute time (i.e. in
UTC time; ignoring DST shifts). To get the end date in the event
time-zone, convert start into UTC, then add the duration, then
convert the result into the appropriate time-zone.
A JSEvent MAY be end in a different time-zone (e.g. a plane flight
crossing time-zones). In this case, the JSEvent MUST specify the end
time-zone in a *location* property value that defines its *rel* to be
"end" and the end time-zone in its *timeZone* property.
5.1.4. isAllDay
Type: "Boolean" (optional, defaults to "false")
Specifies if the event an all day event, such as a birthday or public
holiday.
If *isAllDay* is true, then the following restrictions apply:
o the *start* property MUST have a time component of "T00:00:00".
o the *duration* property MUST only include a day component.
Note that all-day events MAY be bound to a specific time-zone, as
defined by the *timeZone* property.
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5.1.5. status
Type: "String"
The scheduling status (Section 4.4) of a JSEvent defaults to
"confirmed" if omitted.
If set, it MUST be one of:
o "confirmed": Indicates the event is definite.
o "cancelled": Indicates the event is cancelled.
o "tentative": Indicates the event is tentative.
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: "LocalDate|null" e.g. "2015-09-02T00:00:00"
The date/time the task is due in the task's time-zone.
5.2.2. start
Type: "LocalDate|null" e.g. "2015-09-02T00:00:00"
The date/time the task should start in the task's time-zone.
5.2.3. timeZone
Type: "String|null"
The IANA Time Zone Database name for the time-zone the task is
scheduled in, or "null" for floating time. If omitted, this MUST be
presumed to be "null" (i.e. floating time).
5.2.4. estimatedDuration
Type: "Duration|null", e.g. "P2DT3H"
Specifies the estimated positive duration of time the task takes to
complete.
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If the *start* and *due* properties are set, the estimated duration
SHOULD be less than or equal to the time interval between these
properties.
5.2.5. completed
Type: "UTCDate|null", e.g. "2016-06-13T12:00:00Z"
Specifies the date/time the task was completed.
If the task is recurring and has future instances, a client may want
to denote a specific task recurrence as completed but leave other
instances as uncompleted. One way to achieve this is by overriding
the completed property in the task *recurrenceOverrides*. However,
this could produce a long list of completion times for regularly
recurring tasks. An alternative approach is to split the JSTask into
a current, single instance of JSTask with this instance completion
time and a future recurring instance. Also see the definition of the
*relatedTo* on splitting.
5.2.6. isAllDay
Type: "Boolean" (optional, defaults to "false")
Specifies if the task is an all day task.
If *isAllDay* is true, then the *start* and *due* properties MUST
have a time component of "T00:00:00". Note that the
*estimatedDuration* property MAY contain a non-zero time duration.
All-day tasks MAY be bound to a specific time-zone, as defined by the
*timeZone* property.
5.2.7. progress
In addition to the common properties of a *Participant* object
(Section 4.4.5), a Participant within a JSTask supports the following
property:
o *progress*: "ParticipantProgress|null" The progress of the
participant for this task, if known.
A *ParticipantProgress* object has the following properties:
o *status*: "String" Describes the completion status of the
participant's progress.
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The value MUST be at most one of the following values, registered
in a future RFC, or a vendor-specific value:
* "completed": The progress of this participant is complete.
* "in-process": The progress of this participant is in process.
o *timestamp*: "UTCDate" Describes the latest time when the
participant progress got updated.
5.2.8. status
Type: "String"
The scheduling status (Section 4.4) of a JSTask defaults to "needs-
action" if omitted.
If set, it MUST be one of:
o "needs-action": Indicates the task needs action.
o "completed": Indicates the task is completed. If this value is
set, then the timestamp in the *completed* property MUST NOT be
null.
o "in-process": Indicates the task is in process.
o "cancelled": Indicates the task is cancelled.
5.3. JSGroup properties
JSGroup supports the following JSCalendar properties (Section 4):
o @type
o uid
o created
o updated
o categories
o keywords
o name
o description
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o htmlDescription
o color
o links
as well as the following JSGroup-specific properties:
5.3.1. entries
Type: "(JSTask|JSEvent)[]|null"
A list of group members. The list MAY contain multiple object types
and implementations MUST ignore entries of unknown type. The
property value MUST either be "null" or the list MUST NOT be empty.
5.3.2. source
Type: "String|null" (optional, default is "null")
The source from which updated versions of this group may be retrieved
from. If the value is not "null", it MUST be a URI.
6. Conversion from and to iCalendar
This section specifies which JSCalendar properties can be mapped from
and to iCalendar format. Implementations SHOULD follow these
conversion guidelines. Still, JSCalendar does not restrict itself to
iCalendar and conversion between these two formats MAY be lossy.
6.1. JSEvent
The iCalendar counterpart to *JSEvent* is the VEVENT component type
[RFC5545]. A VEVENT component that is a direct child of a VCALENDAR
component is equivalent to a standalone JSEvent. A VEVENT component
*within* a VEVENT maps to the entries of the JSEvent
*recurrenceOverrides* property.
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+----------+--------------------------------------------------------+
| Property | iCalendar counterpart |
+----------+--------------------------------------------------------+
| isAllDay | True, if the type of the DTSTART property in iCalendar |
| | is DATE. When translating from JSCalendar the |
| | iCalendar DTSTART property is of DATE value type, if |
| | the *isAllDay* property is set to true and the |
| | *timeZone* property is null. |
| | |
| start | Corresponds to the DTSTART property in iCalendar. Note |
| | that time-zone information is stored separately in |
| | JSEvent. |
| | |
| timeZone | Corresponds to the TZID part of the DTSTART property |
| | in iCalendar. If the event has a different end time- |
| | zone to start time-zone, this should be added as a |
| | JSCalendar *location* with just a *timeZone* property |
| | and "rel="end"". |
| | |
| duration | Corresponds to the DURATION or DSTART+DTEND properties |
| | in iCalendar. |
+----------+--------------------------------------------------------+
Table 2: Translation between JSEvent and iCalendar
6.2. JSTask
The iCalendar counterpart to *JSTask* is the VTODO component type
[RFC5545]. A VTODO component that is a direct child of a VCALENDAR
component is equivalent to a standalone JSTask. A VTODO component
*within* a master VTODO maps to the entries of the JSTask
*recurrenceOverrides* property.
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+-------------------+-----------------------------------------------+
| Property | iCalendar counterpart |
+-------------------+-----------------------------------------------+
| isAllDay | True, if the type of the DTSTART property in |
| | iCalendar is DATE. When translating from |
| | JSCalendar the iCalendar DTSTART property is |
| | of DATE value type, if the *isAllDay* |
| | property is set to true and the *timeZone* |
| | property is null. |
| | |
| due | Corresponds to the DUE and DTSTART+DURATION |
| | properties in iCalendar. When mapping |
| | iCalendar VTODOs with DTSTART+DURATION, the |
| | due date is the result of adding DURATION to |
| | DTSTART in the DTSTART time-zone. |
| | |
| start | Corresponds to the DTSTART property in |
| | iCalendar. |
| | |
| timeZone | Corresponds to the TZID part of the |
| | DTSTART/DUE properties in iCalendar. If the |
| | task has a different end time-zone to start |
| | or due time-zone, this should be added as a |
| | JSCalendar *location* with just a *timeZone* |
| | property and "rel="end"". |
| | |
| estimatedDuration | Corresponds to the ESTIMATED-DURATION |
| | iCalendar property. *NON-STANDARD*: this |
| | property is currently non-standard, see |
| | [draft-apthorp-ical-tasks]. |
| | |
| completed | Maps to the COMPLETED iCalendar property. |
| | |
| progress | Corresponds to the PARTSTAT and COMPLETED |
| | properties in iCalendar. |
+-------------------+-----------------------------------------------+
Table 3: Translation between JSTask and iCalendar
6.3. JSGroup
A JSGroup converts to a iCalendar VCALENDAR containing VEVENT or
VTODO components.
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+----------+--------------------------------------------------------+
| Property | iCalendar counterpart |
+----------+--------------------------------------------------------+
| entries | The VEVENT and VTODO components within a top-level |
| | VCALENDAR component. |
| | |
| source | Corresponds to the SOURCE property in iCalendar. |
+----------+--------------------------------------------------------+
Table 4: Translation between JSGroup and iCalendar
6.4. Common properties
+---------------------+---------------------------------------------+
| Property | iCalendar counterpart |
+---------------------+---------------------------------------------+
| alerts | An *Alert* corresponds to the VALARM |
| | component in iCalendar, where the *action* |
| | is determined by the iCalendar ACTION |
| | property value (e.g., a "DISPLAY" property |
| | indicates that the JSCalendar Alert action |
| | is a *DisplayAction* and similarly an |
| | iCalendar "EMAIL" value for *EmailAction* |
| | action). The *relativeTo* and *offset* |
| | properties corresponds to the iCalendar |
| | TRIGGER property. *NON-STANDARD*: The |
| | iCalendar properties for JSCalendar Alert |
| | actions are non-standard, see |
| | [draft-daboo-valarm-extensions]. |
| | |
| categories | Corresponds to the STRUCTURED-CATEGORY |
| | property in iCalendar, see. *NON- |
| | STANDARD*: this property is currently non- |
| | standard, see |
| | [draft-ietf-calext-ical-relations]. |
| | |
| color | Corresponds to the COLOR property in |
| | iCalendar, as specified in [RFC7986]. |
| | |
| created | Corresponds to the CREATED property in |
| | iCalendar. |
| | |
| description | Corresponds to the DESCRIPTION property in |
| | iCalendar. |
| | |
| htmlDescription | There is no direct equivalent in iCalendar. |
| | If the *description* is empty, |
| | implementations SHOUD store a plain text |
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| | version of *htmlDescription* in iCalendar |
| | DESCRIPTION. |
| | |
| freeBusyStatus | Corresponds to the TRANSP property in |
| | iCalendar. |
| | |
| keywords | Corresponds to the CATEGORIES property in |
| | iCalendar, as specified in [RFC7986]. |
| | |
| links | Corresponds to the ATTACH ([RFC5545]) and |
| | IMAGE iCalendar properties ([RFC7986]). |
| | |
| locale | Corresponds to the LANGUAGE parameter in |
| | iCalendar, which is added to individual |
| | properties. When converting from |
| | iCalendar, one language must be picked as |
| | the main locale for the object, and all |
| | properties in other languages moved to the |
| | localizations JSEvent property. |
| | |
| localizations | Corresponds to the LANGUAGE parameter in |
| | iCalendar, which is added to individual |
| | properties. When converting from |
| | iCalendar, one language must be picked as |
| | the main locale for the object, and all |
| | properties in other languages moved to the |
| | localizations JSEvent property. |
| | |
| locations | See Section 6.5. |
| | |
| method | Corresponds to the METHOD property in |
| | iCalendar. |
| | |
| participants | See Section 6.5. |
| | |
| priority | Corresponds to the PRIORITY property in |
| | iCalendar. |
| | |
| privacy | Corresponds to the CLASS property in |
| | iCalendar. |
| | |
| prodId | Corresponds to the PRODID property in |
| | iCalendar. |
| | |
| recurrenceOverrides | Corresponds to the RDATE and EXDATE |
| | properties in iCalendar, plus VEVENT (for |
| | JSEvent) or VTODO (for JSTask) instances |
| | with a recurrence-id. |
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| | |
| recurrenceRule | Corresponds to the RRULE property in |
| | iCalendar. See the property definition at |
| | section Section 4.3.1 how to map a RRULE |
| | value. |
| | |
| relatedTo | Corresponds to the RELATED-TO property in |
| | iCalendar. |
| | |
| replyTo | A *replyTo* property of type "imip" |
| | corresponds to the email address of the |
| | ORGANIZER property in iCalendar. There is |
| | no iCalendar representation for the "web" |
| | type. |
| | |
| sequence | Corresponds to the SEQUENCE property in |
| | iCalendar. |
| | |
| status | Corresponds to the STATUS property in |
| | iCalendar (converted to lower-case). |
| | |
| title | Corresponds to the SUMMARY property in |
| | iCalendar. |
| | |
| uid | Corresponds to the UID property in |
| | iCalendar. |
| | |
| updated | Corresponds to the DTSTAMP and LAST- |
| | MODIFIED properties in iCalendar. (These |
| | are only different in the iTIP case, and |
| | the difference is not actually useful.) |
+---------------------+---------------------------------------------+
Table 5: Translation between JSCalendar and iCalendar
6.5. Locations and participants
Both JSCalendar participants and locations have counterparts in
iCalendar but provide richer representation.
The following table outlines translation of JSCalendar participants.
Where iCalendar has distinct properties for ORGANIZER and ATTENDEE,
these are merged in JSCalendar into the Participant object type.
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+------------------+------------------------------------------------+
| Property | iCalendar counterpart |
+------------------+------------------------------------------------+
| name | the CN parameter |
| | |
| kind | the CUTYPE parameter |
| | |
| rsvpResponse | the PARTSTAT parameter |
| | |
| role | the ORGANIZER and ATTENDEE properties. Owners |
| | map to the iCalendar ORGANIZER property, where |
| | mapping multiple owners to iCalendar is |
| | implementation-specific but MUST be consistent |
| | across mappings of the same object. |
| | |
| participation | the ROLE parameter |
| | |
| locationId | the JSCalendar identifier of a mapped |
| | CONFERENCE property that has the MODERATOR |
| | feature defined in its FEATURE parameter |
| | values. If multiple such CONFERENCE properties |
| | are defined in iCalendar, then the one with |
| | the most interactive features is chosen (VIDEO |
| | over AUDIO over CHAT over anything else). |
| | |
| rsvpWanted | the RSVP parameter |
| | |
| delegatedTo | the DELEGATED-TO parameter |
| | |
| delegatedFrom | the DELEGATED-FROM parameter |
| | |
| memberOf | the MEMBER parameter |
| | |
| scheduleSequence | the SEQUENCE property of the participant's |
| | latest iMIP message |
| | |
| scheduleUpdated | the DTSTAMP property of the participant's |
| | latest iMIP message |
+------------------+------------------------------------------------+
Table 6: Translation of Participant between JSCalendar and iCalendar
For JSCalendar locations, the iCalendar counterparts are the
[RFC5545] LOCATION and the extended iCalendar [RFC7986] CONFERENCE
properties.
An iCalendar LOCATION property becomes a JSCalendar Location with
just a description property. CONFERENCE property values in iCalendar
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map to locations with *rel* type "virtual". The location *feature*
property value corresponds to the extended iCalendar FEATURE property
parameter values defined in [RFC7986]. Both iCalendar PHONE and
AUDIO features map to the "audio" feature and the FEED parameter
value is omitted. See the mapping for *locationId* in Table 6 on how
to map CONFERENCE properties that contain the MODERATOR feature.
6.6. Unknown properties
Both JSCalendar and iCalendar calendar objects may contain properties
that are not expressible in the other format. This specification
does not mandate how to preserve these properties. Instead, it
leaves negotiation on how to treat unknown properties to client and
server implementations and their protocol used to exchange calendar
objects.
Two notable options to represent and preserve arbitrary iCalendar
object properties in JSCalendar are:
o *JCal*: Define iCalendar properties in JCal format ([RFC7265]) in
a vendor-specific property of the JCalendar object. The JCal-
formatted value may either only contain iCalendar properties that
were not mapped to JSCalendar properties, or contain the complete
iCalendar object representation.
o *Alternate link*: Define an alternate link (Section 4.2.5) value
pointing to the iCalendar representation of the JSCalendar object.
E.g. the alternative representation of a VEVENT would be
represented as a link with rel "alternate" and type "text/
calendar;component=VEVENT".
7. JSCalendar object 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.
7.1. Simple event
This example illustrates a simple one-time event. It specifies a
one-time event that begins on January 15, 2018 at 1pm New York local
time and ends after 1 hour.
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{
"@type": "jsevent",
"uid": "2a358cee-6489-4f14-a57f-c104db4dc2f1",
"updated": "2018-01-15T18:00:00Z",
"title": "Some event",
"start": "2018-01-15T13:00:00",
"timeZone": "America/New_York",
"duration": "PT1H"
}
7.2. Simple task
This example illustrates a simple task for a plain to-do item.
{
"@type": "jstask",
"uid": "2a358cee-6489-4f14-a57f-c104db4dc2f2",
"updated": "2018-01-15T18:00:00Z",
"title": "Do something"
}
7.3. Simple group
This example illustrates a simple calendar object group that contains
an event and a task.
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{
"@type": "jsgroup",
"uid": "2a358cee-6489-4f14-a57f-c104db4dc343",
"updated": "2018-01-15T18:00:00Z",
"name": "A simple group",
"entries": [
{
"@type": "jsevent",
"uid": "2a358cee-6489-4f14-a57f-c104db4dc2f1",
"updated": "2018-01-15T18:00:00Z",
"title": "Some event",
"start": "2018-01-15T13:00:00",
"timeZone": "America/New_York",
"duration": "PT1H"
},
{
"@type": "jstask",
"uid": "2a358cee-6489-4f14-a57f-c104db4dc2f2",
"updated": "2018-01-15T18:00:00Z",
"title": "Do something"
}
]
}
7.4. 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",
"isAllDay": true,
"start": "1900-04-01T00:00:00",
"duration": "P1D",
"recurrenceRule": {
"frequency": "yearly"
}
}
7.5. 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, 2018. The
calendar user expects to need 1 hour for shopping.
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{
"...": "",
"title": "Buy groceries",
"due": "2018-01-19T18:00:00",
"timeZone": "Europe/Vienna",
"estimatedDuration": "PT1H"
}
7.6. 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, 2018 at 9am in
Berlin local time. The duration of the flight is scheduled at 10
hours 30 minutes. The time at the flights 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.
{
"...": "",
"title": "Flight XY51 from FRA to NRT",
"start": "2018-04-01T09:00:00",
"timeZone": "Europe/Berlin",
"duration": "PT10H30M",
"locations": {
"2a358cee-6489-4f14-a57f-c104db4dc2f1": {
"rel": "end",
"timeZone": "Asia/Tokyo"
}
}
}
7.7. Floating-time event (with recurrence)
This example illustrates the use of floating-time. Since January 1,
2018, 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": "2018-01-01T07:00:00",
"duration": "PT30M",
"recurrenceRule": {
"frequency": "daily"
}
}
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7.8. 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 convert on premises or
online. The event title and descriptions are localized. (Note: the
localization of the event description contains an UTF-8 encoded
German Umlaut. This characte r may have been replaced with ASCII
characters in the plain-text rendering of this RFC document.)
{
"...": "",
"title": "Live from Music Bowl: The Band",
"description": "Go see the biggest music event ever!",
"locale": "en",
"start": "2018-07-04T17:00:00",
"timeZone": "America/New_York",
"duration": "PT3H",
"locations": {
"9366e041-bb4c-4aa4-b249-b4657cab925c": {
"name": "The Music Bowl",
"description": "Music Bowl, Central Park, New York",
"coordinates": "geo:40.7829,73.9654"
},
"6f3696c6-1e07-47d0-9ce1-f50014b0041a": {
"name": "Free live Stream from Music Bowl",
"rel": "virtual",
"features": [
"video",
"audio",
"chat"
],
"uri": "https://stream.example.com/the_band_2018"
}
},
"localizations": {
"de": {
"title": "Live von der Music Bowl: The Band!",
"description": "Schau dir das groesste Musikereignis an!",
"locations/6f3696c6-1e07-47d0-9ce1-f50014b0041a/name":
"Gratis Live-Stream aus der Music Bowl"
}
}
}
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7.9. 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, 2018
at 9am London time and occurs every week until June 25, 2018. 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 2, May 7 and May 28 no course is held.
{
"...": "",
"title": "Calculus I",
"start": "2018-01-08T09:00:00",
"timeZone": "Europe/London",
"duration": "PT1H30M",
"locations": {
"2a358cee-6489-4f14-a57f-c104db4dc2f1": {
"title": "Math lab room 1",
"description": "Math Lab I, Department of Mathematics"
},
"recurrenceRule": {
"frequency": "weekly",
"until": "2018-06-25T09:00:00"
},
"2018-04-02T09:00:00": null,
"2018-05-07T09:00:00": null,
"2018-05-28T09:00:00": null,
"2018-06-25T09:00:00": {
"title": "Calculus I Exam",
"start": "2018-06-25T10:00:00",
"duration": "PT2H",
"locations": {
"2a358cee-6489-4f14-a57f-c104db4dc2f1": {
"title": "Big Auditorium",
"description": "Big Auditorium, Other Road"
}
}
}
}
}
7.10. Recurring event with participants
This example illustrates scheduled events. A team meeting occurs
every week since January 8, 2018 at 9am Johannesburg time. The event
owner also chairs the event. Participants meet in a virtual meeting
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room. An attendee has accepted the invitation, but on March 8, 2018
he is unavailable and declined participation for this occurrence.
{
"...": "",
"title": "FooBar team meeting",
"start": "2018-01-08T09:00:00",
"timeZone": "Africa/Johannesburg",
"duration": "PT1H",
"locations": {
"2a358cee-6489-4f14-a57f-c104db4dc2f1": {
"title": "ChatMe meeting room",
"rel": "virtual",
"features": [
"audio",
"chat",
"video"
],
"uri": "https://chatme.example.com?id=1234567"
}
},
"recurrenceRule": {
"frequency": "weekly"
},
"replyTo": {
"imip": "zoe@foobar.example.com"
},
"participants": {
"tom@foobar.example.com": {
"name": "Tom Tool",
"email": "tom@foobar.example.com",
"rsvpResponse": "accepted",
"roles": [
"attendee"
]
},
"zoe@foobar.example.com": {
"name": "Zoe Zelda",
"email": "zoe@foobar.example.com",
"rsvpResponse": "accepted",
"roles": [
"owner",
"chair"
]
},
"...": ""
},
"recurrenceOverrides": {
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"2018-03-08T09:00:00": {
"participants/tom@foobar.example.com/rsvpResponse": "declined"
}
}
}
8. Security Considerations
The use of JSON as a format does have its own inherent security risks
as discussed in Section 12 of [RFC8259]. Even though JSON is
considered a safe subset of JavaScript, it should be kept in mind
that a flaw in the parser processing JSON could still impose a
threat, which doesn't arise with conventional iCalendar data.
With this in mind, a parser for JSON data aware of the security
implications should be used for the format described in this
document. For example, the use of JavaScript's "eval()" function is
considered an unacceptable security risk, as described in Section 12
of[RFC8259]. A native parser with full awareness of the JSON format
should be preferred.
9. IANA Considerations
This document amends the "application/calendar" MIME media type
defined in [RFC7265].
New optional parameter: "type" with value being one of "jsevent",
"jstask", "jsgroup". The parameter MUST NOT occur more than once.
10. 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.
11. References
11.1. Normative References
[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>.
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[RFC2183] Troost, R., Dorner, S., and K. Moore, Ed., "Communicating
Presentation Information in Internet Messages: The
Content-Disposition Header Field", RFC 2183,
DOI 10.17487/RFC2183, August 1997,
<https://www.rfc-editor.org/info/rfc2183>.
[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>.
[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>.
[RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault,
"Calendaring Extensions to WebDAV (CalDAV)", RFC 4791,
DOI 10.17487/RFC4791, March 2007,
<https://www.rfc-editor.org/info/rfc4791>.
[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>.
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[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>.
[RFC6570] Gregorio, J., Fielding, R., Hadley, M., Nottingham, M.,
and D. Orchard, "URI Template", RFC 6570,
DOI 10.17487/RFC6570, March 2012,
<https://www.rfc-editor.org/info/rfc6570>.
[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>.
[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>.
[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>.
[RFC7986] Daboo, C., "New Properties for iCalendar", RFC 7986,
DOI 10.17487/RFC7986, October 2016,
<https://www.rfc-editor.org/info/rfc7986>.
[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>.
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11.2. Informative References
[draft-apthorp-ical-tasks]
"Task Extensions to iCalendar",
<https://tools.ietf.org/html/draft-apthorp-ical-tasks>.
[draft-daboo-valarm-extensions]
"VALARM Extensions for iCalendar",
<https://tools.ietf.org/html/
draft-daboo-valarm-extensions>.
[draft-ietf-calext-ical-relations]
"Support for iCalendar Relationships",
<https://tools.ietf.org/html/
draft-ietf-calext-ical-relations>.
11.3. URIs
[1] https://www.w3.org/TR/html/
[2] https://www.iana.org/assignments/link-relations/link-
relations.xhtml
[3] https://www.w3.org/TR/2011/REC-css3-color-20110607/#svg-color
[4] http://www.iana.org/time-zones
Authors' Addresses
Neil Jenkins
FastMail
PO Box 234
Collins St West
Melbourne VIC 8007
Australia
Email: neilj@fastmailteam.com
URI: https://www.fastmail.com
Jenkins & Stepanek Expires July 23, 2018 [Page 50]
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Robert Stepanek
FastMail
PO Box 234
Collins St West
Melbourne VIC 8007
Australia
Email: rsto@fastmailteam.com
URI: https://www.fastmail.com
Jenkins & Stepanek Expires July 23, 2018 [Page 51]
