JSCalendar: A JSON representation of calendar dataFastMailPO Box 234Collins St WestMelbourneVIC 8007Australianeilj@fastmailteam.comhttps://www.fastmail.comFastMailPO Box 234Collins St WestMelbourneVIC 8007Australiarsto@fastmailteam.comhttps://www.fastmail.com
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JSON data formats for iCalendarJSONiCalendarcalendareventsdatetime
This specification defines a 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.
The iCalendar data format, 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 backwards incompatible changes.
For example, iCalendar defines various formats for local times, UTC time and dates, which shows to
confuse new users. Other sources for errors are the requirement for custom timezone 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 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 format, which is a direct
mapping between iCalendar and JSON. However, it did not attempt to extend or update iCalendar semantics.
This document defines a JSON-based format describing a single event or task object within a calendar,
or a group of such objects, using a new data model that aims to be unambiguous, extendable and simple to
process.
The key design considerations for this format are as follows:
The attributes of the calendar entry represented must be described as a simple key-value pair,
reducing complexity of its representation.
The data format should avoid all ambiguities, making it difficult to make mistakes during
implementation and increasing interoperability.
Most of the initial set of attributes should be taken from the iCalendar data format, but a
conversion between the data formats is not guaranteed to be completed without losing semantic
meaning.
Extensions, such as new properties and components, MUST NOT lead to requiring an update to this
document.
JSON is a text-based data interchange format as specified in.
The I-JSON format defined in is a strict subset of this, adding restrictions to
avoid potentially confusing scenarios (for example, it mandates that an object MUST NOT have two
properties with the same key). Using JSON allows to decrease interoperability issues and helps to
speed up adoption due to its widespread adoption.
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
.
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.
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.
A JSCalendar object is a JSON object, which MUST be valid I-JSON (a stricter subset of JSON), as
specified in. 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.
Types signatures are given for all JSON objects in this document. The following conventions are
used:
Boolean|String:
The value is either a JSON Boolean value, or a JSON
String value.
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.
Foo[]:
An array of objects of type Foo.
String[Foo]:
A JSON Object being used as a map (associative array), where
all the values are of type Foo.
In addition to the standard JSON data types, the following data types are used in this
specification:
This is a string in
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 (so, 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.
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.
A duration is represented by a subset of ISO8601 duration format, as specified by the following
ABNF:
In addition, the duration MUST NOT include fractional second values unless the fraction is
non-zero.
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
JSON pointer format, with an implicit leading / (i.e. prefix each
key with / before applying the JSON pointer evaluation algorithm).
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). Any patch with a key that attempts to do
this MUST be ignored.
When evaluating a path, all parts prior to the last (i.e. the value after the final slash) MUST
exist for the patch to be valid. If not, the patch MUST be ignored.
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 result in this case is undefined.
The value associated with each pointer is either:
null: Remove the property from the patched object. If not
present in the parent, this a no-op.
Anything else: The value to replace the inherited property on the patch object with (if
present) or add to the property (if not present).
Vendors MAY add additional properties to the calendar object to support their custom features. The
names of these properties SHOULD be prefixed with a domain name controlled by the vendor to avoid
conflict, e.g. fastmail.com/customprop. Other systems that interact with
a JSCalendar object that contain properties they do not recognise SHOULD try to preserve them, but
MUST otherwise ignore them.
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. fastmail.com/customrel, unless otherwise noted.
JSCalendar objects share a set of properties, but not all JSCalendar support the same properties.
Refer to the respective object type definitions () which common
properties they support.
Type:
StringSpecifies the type which this object represents.
A valid JSCalendar object MUST include this property.
Type:
String
A globally unique identifier, used to associate the object as the same across different systems,
calendars and views. Note that all JSCalendar objects share the same id space, so there MUST NOT
be two JSCalendar objects of different type with the same uid.
A valid JSCalendar object MUST include this property.
Type:
String[Relation]|null
Relates the object to other objects of the same type. This is represented as a map of the uid of
the related object to information about the relation.
A Relation object has the following properties:
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
should 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 SHOULD 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 SHOULD 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.
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.
Type:
UTCDate|null
The date and time this object was initially created.
Type:
UTCDate
The date and time the data in this object was last modified.
Type: Number (Defaults to 0 if omitted)
Initially zero, this is monotonically incremented each time a significant change is made to the
object.
Type:
String|null
The iTIP () method, in lower-case. Used for scheduling.
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
and.
Objects recur by applying the recurrence rule (and
recurrenceOverrides) to the start date/time.
A JSTask without a start recurs by
its due date/time, if defined.
A Recurrence object has the following properties:
frequency:
String
This MUST be one of the following values:
yearlymonthlyweeklydailyhourlyminutelysecondly
To convert from iCalendar, simply lower-case the FREQ part.
interval: Number(optional,
defaults to 1)
The INTERVAL part from iCal. If included, it MUST be an integer x >=
1.
rscale: String(optional,
defaults to "gregorian")
The RSCALE part from iCalendar RSCALE, converted to
lower-case.
skip: String(optional,
defaults to "omit")
The SKIP part from iCalendar RSCALE, converted to
lower-case.
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".
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)
If present, rather than representing every Friday (for example), it represents
only a specific instance within the period (month for monthly recurrences, year
for yearly recurrences). Must be a non-zero integer, negative integers means
nth-last of period. This is the "+1" or "-3"
etc. prefix from the BYDAY values in iCal.
byDate: Number[](optional)
The BYMONTHDAY part from iCalendar. The array MUST have at least one entry if included.
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 ) for
leap months (this MUST be upper-case, e.g. "3L").
The array MUST have at least one entry if included.
byYearDay: Number[](optional)
The BYYEARDAY part from iCalendar. The array MUST have at least one entry if included.
byWeekNo: Number[](optional)
The BYWEEKNO part from iCalendar. The array MUST have at least one entry if included.
byHour: Number[](optional)
The BYHOUR part from iCalendar. The array MUST have at least one entry if included.
byMinute: Number[](optional)
The BYMINUTE part from iCalendar. The array MUST have at least one entry if included.
bySecond: Number[](optional)
The BYSECOND part from iCalendar. The array MUST have at least one entry if included.
count: Number(optional)
The COUNT part from iCalendar. This MUST NOT be included if an
until property is specified.
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 timezone specified in
timeZone. It is not a UTC time.
Type:
LocalDate[PatchObject|null]|null
The object is a map of the Recurrence-Id (i.e. 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 event 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:
uid
relatedTo
prodId
method
isAllDay
recurrenceRule
recurrenceOverrides
replyTo
Type: String (Defaults to the empty string if omitted)
A short summary of the object.
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.
Type:
String[Location]|null
A map of of location id 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:
name:
String
The human-readable name of the location.
description:
String
Human-readable instructions for accessing this location. This may be an address, set of
directions, door access code, etc.
rel:
String
The relation type of this location to the JSCalendar object.
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 event
is unknown.
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 capability
chat: chat or instant messaging
feed: a blog or Atom feed
moderator: moderator-specific
phone: phone conference
screen: screen sharing
video: video conferencing
any vendor-prefixed custom value
timeZone:
String
A time zone for this location.
If omitted, the start time zone MUST be used for this location.
coordinates:
String
An
geo:
URI for the location.
uri:
String
A URI that represents how to connect from 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 a
custom URI for something like Skype (e.g. skype:username).
linkIds:
String[]|null
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.
Type:
String[Link]|null
A map of of link id 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:
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.
type: String|null(optional,
defaults to null)
The content-type of the resource, if known.
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.
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).
The features supported by locations with rel-type virtual are:
Links with a rel of enclosure SHOULD be considered by the
client as attachments for download.
Links with a rel of describedby SHOULD be considered by the
client to be an alternate representation of the description, for example an HTML page
describing the object.
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
title: String|null(optional,
defaults to null)
A human-readable description of the resource.
properties:
String[String|null]|null(optional, defaults to null)
Extra metadata stored by a client about a link.
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.
Type:
String|null
The
language tag that best describes the locale used for the event, if known.
Type:
String[PatchObject]|null
A map of
language tag to a patch object which localises the event into that locale.
See the description of PatchObject for the
structure of the PatchObject. The patches are applied to the top-level object. In addition to
all the restrictions on patches specified there, the pointer also MUST NOT start with one of the
following prefixes; any patch with a such a key MUST be ignored:
sequence
localization
start
timeZone
duration
status
freeBusyStatus
participants
useDefaultAlerts
Type:
String[]|nullSpecifies the categories related to the calendar object. Array values MUST be URIs.
Type:
String[]|null
A list of keywords or tags related to the object. The values are freeform and do not have to
follow any particular structure.
Type:
StringSpecifies a color clients MAY use when displaying this event. 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. It is not intended that clients necessarily use the
exact RGB value associated with this color name, but rather that they use the name to find a
suitable color that works in the given UA context.
Type: String(defaults to "confirmed" if
omitted)
The status of the object. MUST be one of:
confirmed: Indicates the calendar object is definite.
cancelled: Indicates the calendar object was cancelled.
tentative: Indicates the calendar object is tentative.
Type: Number(defaults to 0 if omitted)
Specifies a priority for the event. 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.
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:
"free": The object should be ignored when calculating
whether the user is busy.
"busy": The object should be included when calculating
whether the user is busy.
Type: String(defaults to public if
omitted)
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.
As JSCalendar is simply a data model, 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. fastmail.com/topsecret. Any value the client or
server doesn't understand should be preserved but treated as equivalent to
private.
public: The full details of the object are visible to those
whom the object's calendar is shared with.
private: The details of the object are hidden; only the
basic time and metadata is shared. Implementations SHOULD ensure the following
properties are stripped when the object is accessed by a sharee:
title
description
locations
links
locale
localizations
participants
replyTo
In addition, any patches in recurrenceOverrides whose key is
prefixed with one of the above properties SHOULD be stripped.
secret: The object is hidden completely (as though it did
not exist) when the calendar is shared.
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 specications; a calendar client MUST just ignore any
method it does not understand.
The following methods are defined:
imip: The organizer accepts an iMIP
response. The value MUST be a mailto: URI.
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.
Type:
String[Participant]|null
A map of participant id to a participant describing their participation in the calendar object.
A participant id may be any string and need only be unique to this event; the email address of
the participant is a good choice.
A Participant object has the following properties. Properties are
mandatory unless marked otherwise:
name: String The display name
of the participant (e.g. "Joe Bloggs").
email: String The email
address for the participant.
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 event
that needs to be scheduled, e.g. a conference room.
unknown: no information is available about the kind
of this participant.
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 organizer of the event,
and allowed to make alterations to any part of the event.
attendee: The participant is an attendee of the
event.
chair: The participant is in charge of the event
when it occurs.
locationId|null: String(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.
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 participant will attend.
declined: The participant may attend.
tentative: The participant will not attend.
participation: String(optional,
defaults to required)
The required attendance 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.
rsvpWanted: Boolean(optional,
defaults to false)
If true, the organizer is expecting the participant to notify them of their status.
scheduleSequence: Number(optional,
defaults to
0)
The sequence number of the last response from the participant.
This can be used to determine whether the partcipant has sent a new RSVP following
significant changes to the event, and to determine if future responses are responding to
a current or older view of the data.
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.
invitedBy: String|null(optional,
defaults to null)
The participant id of the participant who invited this one, if known.
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).
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).
memberOf: String[]|null(optional,
defaults to null)
A list of group addresses 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).
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).
Type: Boolean (defaults to false if
omitted)
If true, use the user's default alerts for this event and ignore the
property. Fetching user defaults is dependent on the API from which this JSCalendar object is
being fetched, and is not defined in this specification.
Type:
String[Alert]|null
A map of of alert id 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 UUID is a practical choice.
An Alert Object has the following properties:
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-startafter-startbefore-endafter-endoffset:
Duration
The offset from the start and end/due of the calendar object to fire the alert. Note, if
the calendar object is in floating time (including all-day events), the server SHOULD
use the user's default time zone when determining the offset.
action:
DisplayAction|EmailAction|UnknownAction
Describes how to alert the user.
A DisplayAction means a message (which is service dependent,
but SHOULD include the summary and start or due time of the calendar object) SHOULD be
shown to the user on any client connected to 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 SHOULD 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 event, the acknowledged property of
the parent event SHOULD 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.
audioLinkId: String|null
(optional)
The id of a link in the
property. If the linked file is of an audio type understood by the client, the
client SHOULD play this audio when triggering the alert.
An EmailAction means the server MUST send an email 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.
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 (such as "Event
Summary: starting in 5 min").
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 event, such as summary, location and start time.
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.
MIME type: application/json+cal;type=event
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.
A JSEvent @type property value MUST be event.
In addition to the common JSCalendar object properties a
JSEvent
has the following properties:
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.
Type:
String|null
The IANA Time Zone Database 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).
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 timezone (e.g. a plane flight crossing
timezones). In this case, the JSEvent SHOULD specify the end timezone in a
location property value that defines its
rel to be end and
the end timezone in its timeZone property.
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:
the start property
MUST have a time component of T00:00:00.
the timeZone property MUST be null (or omitted).
the duration property MUST only include a day
component.
MIME type: application/json+cal;type=task
A JSTask represents an action-item, assignment, to-do or work item .
A JSTask @type property value MUST be task.
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 required. This notably differs from
JSEvent which is required to start at a certain point in time and typically takes some
non-zero duration to complete.
In addition to the common JSCalendar object properties as
JSTask has the following properties:
Type: LocalDate|null e.g.
2015-09-02T00:00:00
The date/time the task is due in the task's time zone.
Type: LocalDate|null e.g.
2015-09-02T00:00:00
The date/time the task should start in the task's time zone.
If the due property is set, the start
property value MUST be earlier
than or at the due date/time.
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).
Type: Duration|null, e.g.
P2DT3HSpecifies the estimated positive duration of time the task takes to complete.
If the start and due properties are
set, the estimated duration SHOULD be less than or equal to the time interval between these
properties.
Type: UTCDate|null, e.g.
2016-06-13T12:00:00ZSpecifies 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
recurrence overrides.
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 property on splitting.
Type: Boolean
(optional, defaults to false)
Specifies if the task is an all day task.
If isAllDay is true, then the following restrictions apply:
the start and due properties
MUST have a time component of T00:00:00.
the timeZone property MUST be null (or omitted).
the duration and
estimatedDuration properties MUST only include a day
component.
MIME type: application/json+cal;type=group
A JSGroup is a collection of JSEvent and
JSTask objects. Typically, objects are grouped by topic
(e.g. by keywords) or calendar membership.
Its @type property value MUST be group.
JSGroup supports the following JSCalendar properties:
@type
uid
updated
categories
keywords
name
description
color
links
as well as the following JSGroup-specific properties:
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.
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 an URI.
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 the expressivity of iCalendar and conversion between these two formats MAY be lossy.
Implementations that serve the same calendar entry in both JSCalendar and iCalendar SHOULD
preserve properties that can not be converted (e.g., a JSCalendar property that can't be translated
to iCalendar MAY be omitted in the iCalendar representation but MUST be preserved in the JSCalendar
format).
The iCalendar counterpart to JSEvent is the VEVENT component type
. 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 (see
).
Corresponds to the type (DATE or DATE-TIME) of the DTSTART property in iCalendar.
Corresponds to the DTSTART property in iCalendar. Note that time zone information is stored
separately in JSEvent.
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".
Corresponds to the DURATION or DSTART+DTEND properties in iCalendar.
The iCalendar counterpart to JSTask is the VTODO component type
. 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 (see
).
Corresponds to the type (DATE or DATE-TIME) of the DTSTART and DUE properties in iCalendar.
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 timezone.
Corresponds to the DTSTART property in iCalendar.
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".
Corresponds to the ESTIMATED-DURATION iCalendar
property.
NON-STANDARD: this property is currently non-standard,
see .
Maps to the COMPLETED iCalendar property.
A JSGroup converts to a iCalendar VCALENDAR containing VEVENT or VTODO components.
The VEVENT and VTODO components within a top-level VCALENDAR component.
Corresponds to the SOURCE property in iCalendar.
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
.
Corresponds to the STRUCTURED-CATEGORY property in iCalendar,
see.
NON-STANDARD: this property is currently non-standard,
see .
Corresponds to the CREATED property in iCalendar.
Corresponds to the DESCRIPTION property in iCalendar.
Corresponds to the TRANSP property in iCalendar.
Corresponds to the COLOR property in iCalendar, as specified in .
Corresponds to the ATTACH () and IMAGE iCalendar properties
().
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.
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.
Corresponds to the LOCATION and CONFERENCE properties in iCalendar.
For LOCATION, the JSCalendar
representation is much richer than is supported by iCalendar. When converting from
iCalendar, the LOCATION property should become a single location with just a description
property. CONFERENCE property values in
iCalendar map to locations with rel type virtual.
A location feature property value corresponds to the FEATURE
property parameter values defined in .
Corresponds to the METHOD property in iCalendar.
Corresponds to the ORGANIZER and ATTENDEES properties from iCalendar.
The following Participant object fields map to iCalendar parameters on the ORGANIZER and
ATTENDEE properties:
name: the CN parameter
kind: the CUTYPE parameter
rsvpResponse: the PARTSTAT parameter
participation: the ROLE parameter
rsvpWanted: the RSVP parameter
delegatedTo: the DELEGATED-TO parameter
delegatedFrom: the DELEGATED-FROM parameter
memberOf: the MEMBER parameter
The scheduleSequence and scheduleUpdated
properties correspond to the iCalendar SEQUENCE and DTSTAMP property values for the
participant's latest iMIP message.
Corresponds to the PRIORITY property in iCalendar.
Corresponds to the CLASS property in iCalendar.
Corresponds to the PRODID property in iCalendar.
Corresponds to the RDATE and EXDATE properties in iCalendar, plus VEVENT (for JSEvent) or
VTODO (for JSTask) instances with a Recurrence-Id.
Corresponds to the RRULE property in iCalendar. See the property definition at section
how to map a RRULE value.
Corresponds to the RELATED-TO property in iCalendar.
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.
Corresponds to the SEQUENCE property in iCalendar.
Corresponds to the STATUS property in iCalendar (converted to lower-case).
Corresponds to the SUMMARY property in iCalendar.
Corresponds to the UID property in iCalendar.
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.)
The following examples illustrate several aspects of the JSCalendar data model and foramt.
This JSEvent object represents a one-time event taking place
on September 28 at 4pm, GMT for one hour.
This JSEvent object represents a recurring event, taking place the first time
on January 1, 2016 at 1pm. It recurs monthly, but does not occur on February 2,
2016. In addition to the regular recurrences it also occurs on December 5, 2016
at 5pm. On May 1, it takes place at another location.
Note that the recurrenceOverride on May 1 overrides the complete location object.
If the event should occur at both locations, the
PatchObject would be defined as follows:
The use of JSON as a format does have its own inherent security risks as discussed in Section 12 of
. 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. A native parser with full awareness of the JSON format should
be preferred.
This document defines a MIME media type for use with iCalendar in JSON data. This media type SHOULD be
used for the transfer of calendaring data in JSON.
The author would like to thank the following for their valuable contributions: (TODO:names). This
specification originated from the work of the API technical committee of CalConnect, the Calendaring and
Scheduling Consortium.
Task Extensions to iCalendarSupport for iCalendar RelationshipsVALARM Extensions for iCalendar