Internet DRAFT - draft-ietf-jmap-calendars
draft-ietf-jmap-calendars
JMAP N.M. Jenkins, Ed.
Internet-Draft Fastmail
Intended status: Standards Track M. Douglass, Ed.
Expires: 28 September 2023 Spherical Cow Group
27 March 2023
JMAP for Calendars
draft-ietf-jmap-calendars-11
Abstract
This document specifies a data model for synchronizing calendar data
with a server using JMAP.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 28 September 2023.
Copyright Notice
Copyright (c) 2023 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. Notational Conventions . . . . . . . . . . . . . . . . . 4
1.2. The LocalDate Data Type . . . . . . . . . . . . . . . . . 4
1.3. The Duration Data Type . . . . . . . . . . . . . . . . . 4
1.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.5. Data Model Overview . . . . . . . . . . . . . . . . . . . 5
1.5.1. UIDs and CalendarEvent Ids . . . . . . . . . . . . . 6
1.6. Addition to the Capabilities Object . . . . . . . . . . . 6
1.6.1. urn:ietf:params:jmap:calendars . . . . . . . . . . . 6
1.6.2. urn:ietf:params:jmap:principals:availability . . . . 7
2. Principals and Sharing . . . . . . . . . . . . . . . . . . . 7
2.1. Principal Capability urn:ietf:params:jmap:calendars . . . 7
2.2. Principal/getAvailability . . . . . . . . . . . . . . . . 8
3. Participant Identities . . . . . . . . . . . . . . . . . . . 10
3.1. ParticipantIdentity/get . . . . . . . . . . . . . . . . . 11
3.2. ParticipantIdentity/changes . . . . . . . . . . . . . . . 11
3.3. ParticipantIdentity/set . . . . . . . . . . . . . . . . . 11
4. Calendars . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1. Calendar/get . . . . . . . . . . . . . . . . . . . . . . 16
4.2. Calendar/changes . . . . . . . . . . . . . . . . . . . . 16
4.3. Calendar/set . . . . . . . . . . . . . . . . . . . . . . 16
5. Calendar Events . . . . . . . . . . . . . . . . . . . . . . . 18
5.1. Additional JSCalendar properties . . . . . . . . . . . . 19
5.1.1. mayInviteSelf . . . . . . . . . . . . . . . . . . . . 19
5.1.2. mayInviteOthers . . . . . . . . . . . . . . . . . . . 20
5.1.3. hideAttendees . . . . . . . . . . . . . . . . . . . . 20
5.2. Attachments . . . . . . . . . . . . . . . . . . . . . . . 20
5.3. Per-user properties . . . . . . . . . . . . . . . . . . . 20
5.4. Recurring events . . . . . . . . . . . . . . . . . . . . 21
5.5. Updating for "this-and-future" . . . . . . . . . . . . . 21
5.5.1. Splitting an event . . . . . . . . . . . . . . . . . 22
5.5.2. Updating the base event and overriding previous . . . 22
5.6. CalendarEvent/get . . . . . . . . . . . . . . . . . . . . 22
5.7. CalendarEvent/changes . . . . . . . . . . . . . . . . . . 24
5.8. CalendarEvent/set . . . . . . . . . . . . . . . . . . . . 24
5.8.1. Patching . . . . . . . . . . . . . . . . . . . . . . 26
5.8.2. Sending invitations and responses . . . . . . . . . . 29
5.9. CalendarEvent/copy . . . . . . . . . . . . . . . . . . . 31
5.10. CalendarEvent/query . . . . . . . . . . . . . . . . . . . 32
5.10.1. Filtering . . . . . . . . . . . . . . . . . . . . . 32
5.10.2. Sorting . . . . . . . . . . . . . . . . . . . . . . 34
5.11. CalendarEvent/queryChanges . . . . . . . . . . . . . . . 34
6. Alerts . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.1. Default alerts . . . . . . . . . . . . . . . . . . . . . 34
6.2. Acknowledging an alert . . . . . . . . . . . . . . . . . 35
6.3. Snoozing an alert . . . . . . . . . . . . . . . . . . . . 35
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6.4. Push events . . . . . . . . . . . . . . . . . . . . . . . 35
7. Calendar Event Notifications . . . . . . . . . . . . . . . . 36
7.1. Auto-deletion of Notifications . . . . . . . . . . . . . 37
7.2. Object Properties . . . . . . . . . . . . . . . . . . . . 37
7.3. CalendarEventNotification/get . . . . . . . . . . . . . . 38
7.4. CalendarEventNotification/changes . . . . . . . . . . . . 38
7.5. CalendarEventNotification/set . . . . . . . . . . . . . . 38
7.6. CalendarEventNotification/query . . . . . . . . . . . . . 38
7.6.1. Filtering . . . . . . . . . . . . . . . . . . . . . . 38
7.6.2. Sorting . . . . . . . . . . . . . . . . . . . . . . . 38
7.7. CalendarEventNotification/queryChanges . . . . . . . . . 39
8. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 39
8.1. Fetching initial data . . . . . . . . . . . . . . . . . . 39
8.2. Creating an event . . . . . . . . . . . . . . . . . . . . 41
8.3. Snoozing an alert . . . . . . . . . . . . . . . . . . . . 43
8.4. Changing the default calendar . . . . . . . . . . . . . . 45
9. Security Considerations . . . . . . . . . . . . . . . . . . . 46
9.1. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 46
9.2. Spoofing . . . . . . . . . . . . . . . . . . . . . . . . 47
9.3. Denial-of-service . . . . . . . . . . . . . . . . . . . . 47
9.3.1. Expanding Recurrences . . . . . . . . . . . . . . . . 47
9.3.2. Firing alerts . . . . . . . . . . . . . . . . . . . . 47
9.3.3. Load spikes . . . . . . . . . . . . . . . . . . . . . 48
9.4. Spam . . . . . . . . . . . . . . . . . . . . . . . . . . 48
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 48
10.1. JMAP Capability Registration for "calendars" . . . . . . 48
10.2. JMAP Capability Registration for
"principals:availability" . . . . . . . . . . . . . . . 49
10.3. Update to the JSCalendar Properties Registry . . . . . . 49
10.3.1. Update to "JSCalendar Properties" Registry
Template . . . . . . . . . . . . . . . . . . . . . . 49
10.3.2. Initial values for existing registrations . . . . . 49
10.4. JSCalendar Property Registrations . . . . . . . . . . . 49
10.4.1. id . . . . . . . . . . . . . . . . . . . . . . . . . 50
10.4.2. baseEventId . . . . . . . . . . . . . . . . . . . . 50
10.4.3. calendarIds . . . . . . . . . . . . . . . . . . . . 50
10.4.4. isDraft . . . . . . . . . . . . . . . . . . . . . . 50
10.4.5. isOrigin . . . . . . . . . . . . . . . . . . . . . . 51
10.4.6. utcStart . . . . . . . . . . . . . . . . . . . . . . 51
10.4.7. utcEnd . . . . . . . . . . . . . . . . . . . . . . . 51
10.4.8. mayInviteSelf . . . . . . . . . . . . . . . . . . . 51
10.4.9. mayInviteOthers . . . . . . . . . . . . . . . . . . 52
10.4.10. hideAttendees . . . . . . . . . . . . . . . . . . . 52
11. Normative References . . . . . . . . . . . . . . . . . . . . 52
12. Informative References . . . . . . . . . . . . . . . . . . . 53
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 53
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1. Introduction
JMAP ([RFC8620] – (U+2013) JSON Meta Application Protocol) is a
generic protocol for synchronizing data, such as mail, calendars or
contacts, between a client and a server. It is optimized for mobile
and web environments, and aims to provide a consistent interface to
different data types.
This specification defines a data model for synchronizing calendar
data between a client and a server using JMAP. The data model is
designed to allow a server to provide consistent access to the same
data via CalDAV [RFC4791] as well as JMAP, however the functionality
offered over the two protocols may differ. Unlike CalDAV, this
specification does not define access to tasks or journal entries
(VTODO or VJOURNAL iCalendar components in CalDAV).
1.1. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Type signatures, examples, and property descriptions in this document
follow the conventions established in Section 1.1 of [RFC8620]. Data
types defined in the core specification are also used in this
document.
1.2. The LocalDate Data Type
Where LocalDate is given as a type, it means a string in the same
format as Date (see [RFC8620], Section 1.4), but with the time-offset
omitted from the end. For example, 2014-10-30T14:12:00. The
interpretation in absolute time depends upon the time zone for the
event, which may not be a fixed offset (for example when daylight
saving time occurs).
1.3. The Duration Data Type
Where Duration is given as a type, it means a length of time
represented by a subset of the ISO 8601 duration format, as defined
in [RFC8984], Section 1.4.6.
1.4. Terminology
The same terminology is used in this document as in the core JMAP
specification, see [RFC8620], Section 1.6.
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The terms ParticipantIdentity, Calendar, CalendarEvent, and
CalendarEventNotification (with these specific capitalizations) are
used to refer to the data types defined in this document and
instances of those data types.
1.5. Data Model Overview
An Account (see [RFC8620], Section 1.6.2) with support for the
calendar data model contains zero or more Calendar objects, which is
a named collection of CalendarEvents. Calendars can also provide
defaults, such as alerts and a color to apply to events in the
calendar. Clients commonly let users toggle visibility of events
belonging to a particular calendar on/off. Servers may allow an
event to belong to multiple Calendars within an account.
A CalendarEvent is a representation of an event or recurring series
of events in JSEvent [RFC8984] format. Simple clients may ask the
server to expand recurrences for them within a specific time period,
and optionally convert times into UTC so they do not have to handle
time zone conversion. More full-featured clients will want to access
the full event information and handle recurrence expansion and time
zone conversion locally.
CalendarEventNotification objects keep track of the history of
changes made to a calendar by other users, allowing calendar clients
to notify the user of changes to their schedule.
The ParticipantIdentity data type represents the identities of the
current user within an Account, which determines which events the
user is a participant of and possibly their permissions related to
that event.
In servers with support for JMAP Sharing [RFC XXX], data may be
shared with other users. Sharing permissions are managed per
calendar. For example, an individual may have separate calendars for
personal and work activities, with both contributing to their free-
busy availability, but only the work calendar shared in its entirety
with colleagues. Principals may also represent schedulable entities,
such as a meeting room.
Users can normally subscribe to any calendar to which they have
access. This indicates the user wants this calendar to appear in
their regular list of calendars. The separate "isVisible" property
stores whether the user would currently like to view the events in a
subscribed calendar.
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1.5.1. UIDs and CalendarEvent Ids
Each CalendarEvent has a uid property ([RFC8984], Section 4.1.2),
which is a globally unique identifier that identifies the same event
in different Accounts, or different instances of the same recurring
event within an Account.
An Account MUST NOT contain more than one CalendarEvent with the same
uid unless all of the CalendarEvent objects have distinct, non-null
values for their recurrenceId property. (This situation occurs if
the principal is added to one or more specific instances of a
recurring event without being invited to the whole series.)
Each CalendarEvent also has an id, which is scoped to the JMAP
Account and used for referencing it in JMAP methods. There is no
necessary link between the uid property and the CalendarEvent's id.
CalendarEvents with the same uid in different Accounts MAY have
different ids.
1.6. Addition to the Capabilities Object
The capabilities object is returned as part of the JMAP Session
object; see [RFC8620], Section 2. This document defines two
additional capability URIs.
1.6.1. urn:ietf:params:jmap:calendars
This represents support for the Calendar, CalendarEvent,
CalendarEventNotification, and ParticipantIdentity data types and
associated API methods. The value of this property in the JMAP
Session capabilities property is an empty object.
The value of this property in an account’ (U+2019)s
accountCapabilities property is an object that MUST contain the
following information on server capabilities and permissions for that
account:
* *maxCalendarsPerEvent*: UnsignedInt|null The maximum number of
Calendars (see Section XXX) that can be can assigned to a single
CalendarEvent object (see Section XXX). This MUST be an integer
>= 1, or null for no limit (or rather, the limit is always the
number of Calendars in the account).
* *minDateTime*: LocalDate The earliest date-time the server is
willing to accept for any date stored in a CalendarEvent.
* *maxDateTime*: LocalDate The latest date-time the server is
willing to accept for any date stored in a CalendarEvent.
* *maxExpandedQueryDuration*: Duration The maximum duration the user
may query over when asking the server to expand recurrences.
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* *maxParticipantsPerEvent*: UnsignedInt|null The maximum number of
participants a single event may have, or null for no limit.
* *mayCreateCalendar*: Boolean If true, the user may create a
calendar in this account.
1.6.2. urn:ietf:params:jmap:principals:availability
Represents support for the Principal/getAvailability method. Any
account with this capability MUST also have the
urn:ietf:params:jmap:principals capability (see [RFC XXX]).
The value of this property in the JMAP Session capabilities property
is an empty object.
The value of this property in an account’ (U+2019)s
accountCapabilities property is an object that MUST contain the
following information on server capabilities and permissions for that
account:
* *maxAvailabilityDuration*: The maximum duration over which the
server is prepared to calculate availability in a single call (see
Section XXX).
2. Principals and Sharing
For systems that also support JMAP Sharing [RFC XXX], the calendars
capability is used to indicate that this principal may be used with
calendaring. A new method is defined to allow users to query
availability when scheduling events.
2.1. Principal Capability urn:ietf:params:jmap:calendars
A "urn:ietf:params:jmap:calendars" property is added to the Principal
"capabilities" object, the value of which is an object with the
following properties:
* *accountId*: Id|null Id of Account with the
urn:ietf:params:jmap:calendars capability that contains the
calendar data for this principal, or null if none (e.g. the
Principal is a group just used for permissions management), or the
user does not have access to any data in the account (with the
exception of free/busy, which is governed by the
mayGetAvailability property). The corresponding Account object
can be found in the principal's "accounts" property, as per [RFC
XXX].
* *mayGetAvailability*: Boolean May the user call the "Principal/
getAvailability" method with this Principal?
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* *mayShareWith*: Boolean May the user add this principal as a
calendar sharee (by adding them to the shareWith property of a
calendar, see Section XXX)?
* *scheduleId*: String If this principal may be added as a
participant to an event, this is the scheduleId to use to
represent it.
* *sendTo*: String[String]|null If this principal may be added as a
participant to an event, this is the Participant#sendTo property
to add (see [RFC8984], Section 4.4.5) for scheduling messages to
reach it.
2.2. Principal/getAvailability
This method calculates the availability of the principal for
scheduling within a requested time period. It takes the following
arguments:
* *accountId*: Id The id of the account to use.
* *id*: Id The id of the Principal to calculate availability for.
* *utcStart*: UTCDate The start time (inclusive) of the period for
which to return availability.
* *utcEnd*: UTCDate The end time (exclusive) of the period for which
to return availability.
* *showDetails*: Boolean If true, event details will be returned if
the user has permission to view them.
* *eventProperties*: String[]|null A list of properties to include
in any JSEvent object returned. If null, all properties of the
event will be returned. Otherwise, only properties with names in
the given list will be returned.
The server will first find all relevant events, expanding any
recurring events. Relevant events are ones where all of the
following is true:
* The principal is subscribed to the calendar.
* The "includeInAvailability" property of the calendar for the
principal is "all" or "attending".
* The user has the "mayReadFreeBusy" permission for the calendar.
* The event finishes after the "utcStart" argument and starts before
the "utcEnd" argument.
* The event's "privacy" property is not "secret".
* The "freeBusyStatus" property of the event is "busy" (or omitted,
as this is the default).
* The "status" property of the event is not "cancelled".
* If the "includeInAvailability" property of the calendar is
"attending", then the principal is a participant of the event, and
has a "participationStatus" of "accepted" or "tentative".
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If an event is in more than one calendar, it is relevant if all of
the above are true for any one calendar that it is in.
The server then generates a BusyPeriod object for each of these
events. A *BusyPeriod* object has the following properties:
* *utcStart*: UTCDate The start time (inclusive) of the period this
represents.
* *utcEnd*: UTCDate The end time (exclusive) of the period this
represents.
* *busyStatus*: String (optional, default "unavailable") This MUST
be one of
- confirmed: The event status is "confirmed".
- tentative: The event status is "tentative".
- unavailable: The principal is not available for scheduling at
this time for any other reason.
* *event*: JSEvent|null The JSEvent representation of the event, or
null if any of the following are true:
- The "showDetails" argument is false.
- The "privacy" property of the event is "private".
- The user does not have the "mayReadItems" permission for any of
the calendars the event is in.
If an eventProperties argument was given, any properties in the
JSEvent that are not in the eventProperties list are removed from
the returned representation.
The server MAY also generate BusyPeriod objects based on other
information it has about the principal's availability, such as office
hours.
Finally, the server MUST merge and split BusyPeriod objects where the
"event" property is null, such that none of them overlap and either
there is a gap in time between any two objects (the utcEnd of one
does not equal the utcStart of another) or those objects have a
different busyStatus property. If there are overlapping BusyPeriod
time ranges with different "busyStatus" properties the server MUST
choose the value in the following order: confirmed > unavailable >
tentative.
The response has the following argument:
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* *list*: BusyPeriod[] The list of BusyPeriod objects calculated as
described above.
The following additional errors may be returned instead of the
"Principal/getAvailability" response:
notFound: No principal with this id exists, or the user does not have
permission to see that this principal exists.
forbidden: The user does not have permission to query this
principal's availability.
tooLarge: The duration between utcStart and utcEnd is longer than the
server is willing to calculate availability for.
rateLimit: Too many availability requests have been made recently and
the user is being rate limited. It may work to try again later.
3. Participant Identities
A ParticipantIdentity stores information about a URI that represents
the user within that account in an event's participants. It has the
following properties:
* *id*: Id (immutable; server-set) The id of the
ParticipantIdentity.
* *name*: String (default: "") The display name of the participant
to use when adding this participant to an event, e.g. "Joe
Bloggs".
* *scheduleId*: String The URI that represents this participant for
scheduling. This URI MAY also be the URI for one of the sendTo
methods.
* *sendTo*: String[String] Represents methods by which the
participant may receive invitations and updates to an event.
The keys in the property value are the available methods and MUST
only contain ASCII alphanumeric characters (A-Za-z0-9). The value
is a URI for the method specified in the key.
* *isDefault*: Boolean (server-set) This SHOULD be true for exactly
one participant identity in any account, and MUST NOT be true for
more than one participant identity within an account. The default
identity should be used by clients whenever they need to choose an
identity for the user within this account, and they do not have
any other information on which to make a choice. For example, if
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creating a scheduled event in this account, the default identity
may be automatically added as an owner. (But the client may
ignore this if, for example, it has its own feature to allow users
to choose which identity to use based on the invitees.)
A participant in an event corresponds to a ParticipantIdentity if the
scheduleId property of the participant is equivalent to the
scheduleId property of the identity after syntax-based normalisation,
as per [RFC3986], Section 6.2.2.
The following JMAP methods are supported.
3.1. ParticipantIdentity/get
This is a standard "/get" method as described in [RFC8620],
Section 5.1. The _ids_ argument may be null to fetch all at once.
3.2. ParticipantIdentity/changes
This is a standard "/changes" method as described in [RFC8620],
Section 5.2.
3.3. ParticipantIdentity/set
This is a standard "/set" method as described in [RFC8620],
Section 5.3, but with the following additional request argument:
* *onSuccessSetIsDefault*: Id|null If an id is given, and all
creates, updates and destroys (if any) succeed without error, the
server will try to set this identity as the default. (For
references to ParticipantIdentity creations, this is equivalent to
a creation-reference, so the id will be the creation id prefixed
with a "#".)
If the id is not found, or the change is not permitted by the server
for policy reasons, it MUST be ignored and the currently default
ParticipantIdentity (if any) will remain as such. No error is
returned to the client in this case.
As per [RFC8620], Section 5.3, if the default is successfully
changed, any changed objects MUST be reported in either the "created"
or "updated" argument in the response as appropriate, with the
server-set value included.
The server MAY restrict the uri values the user may claim, for
example only allowing mailto: URIs with email addresses that belong
to the user. A standard forbidden error is returned to reject non-
permissible changes.
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4. Calendars
A Calendar is a named collection of events. All events are
associated with at least one calendar.
A *Calendar* object has the following properties:
* *id*: Id (immutable; server-set) The id of the calendar.
* *name*: String The user-visible name of the calendar. This may be
any UTF-8 string of at least 1 character in length and maximum 255
octets in size.
* *description*: String|null (default: null) An optional longer-form
description of the calendar, to provide context in shared
environments where users need more than just the name.
* *color*: String|null (default: null) A color to be used when
displaying events associated with the calendar.
If not null, the value MUST be a case-insensitive color name taken
from the set of names defined in Section 4.3 of CSS Color Module
Level 3 COLORS (https://www.w3.org/TR/css-color-3/), or an RGB value
in hexadecimal notation, as defined in Section 4.2.1 of CSS Color
Module Level 3.
The color SHOULD have sufficient contrast to be used as text on a white background.
* *sortOrder*: UnsignedInt (default: 0) Defines the sort order of
calendars when presented in the client's UI, so it is consistent
between devices. The number MUST be an integer in the range 0 <=
sortOrder < 2^(31.)
A calendar with a lower order should be displayed before a
calendar with a higher order in any list of calendars in the
client's UI. Calendars with equal order SHOULD be sorted in
alphabetical order by name. The sorting should take into account
locale-specific character order convention.
* *isSubscribed*: Boolean Has the user indicated they wish to see
this Calendar in their client? This SHOULD default to false for
Calendars in shared accounts the user has access to and true for
any new Calendars created by the user themself.
If false, the calendar should only be displayed when the user
explicitly requests it or to offer it for the user to subscribe
to.
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* *isVisible*: Boolean (default: true) Should the calendar's events
be displayed to the user at the moment? Clients MUST ignore this
property if isSubscribed is false. If an event is in multiple
calendars, it should be displayed if isVisible is true for any of
those calendars.
* *isDefault*: Boolean (server-set) This SHOULD be true for exactly
one calendar in any account, and MUST NOT be true for more than
one calendar within an account. The default calendar should be
used by clients whenever they need to choose a calendar for the
user within this account, and they do not have any other
information on which to make a choice. For example, if the user
creates a new event, the client may automatically set the event as
belonging to the default calendar from the user's primary account.
* *includeInAvailability*: String Should the calendar's events be
used as part of availability calculation? This MUST be one of:
- all: all events are considered.
- attending: events the user is a confirmed or tentative
participant of are considered.
- none: all events are ignored (but may be considered if also in
another calendar).
This should default to "all" for the calendars in the user's own
account, and "none" for calendars shared with the user.
* *defaultAlertsWithTime*: Id[Alert]|null A map of alert ids to
Alert objects (see [RFC8984], Section 4.5.2) to apply for events
where "showWithoutTime" is false and "useDefaultAlerts" is true.
Ids MUST be unique across all default alerts in the account,
including those in other calendars; a UUID is recommended.
If omitted on creation, the default is server dependent. For
example, servers may choose to always default to null, or may copy
the alerts from the default calendar.
* *defaultAlertsWithoutTime*: Id[Alert]|null A map of alert ids to
Alert objects (see [RFC8984], Section 4.5.2) to apply for events
where "showWithoutTime" is true and "useDefaultAlerts" is true.
Ids MUST be unique across all default alerts in the account,
including those in other calendars; a UUID is recommended.
If omitted on creation, the default is server dependent. For
example, servers may choose to always default to null, or may copy
the alerts from the default calendar.
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* *timeZone*: String|null (default: null) The time zone to use for
events without a time zone when the server needs to resolve them
into absolute time, e.g., for alerts or availability calculation.
The value MUST be a time zone id from the IANA Time Zone Database
TZDB (https://www.iana.org/time-zones). If null, the timeZone of
the account's associated Principal will be used. Clients SHOULD
use this as the default for new events in this calendar if set.
* *shareWith*: Id[CalendarRights]|null (default: null) A map of
Principal id to rights for principals this calendar is shared
with. The principal to which this calendar belongs MUST NOT be in
this set. This is null if the calendar is not shared with anyone.
May be modified only if the user has the mayAdmin right. The
account id for the principals may be found in the
urn:ietf:params:jmap:principals:owner capability of the Account to
which the calendar belongs.
* *myRights*: CalendarRights (server-set) The set of access rights
the user has in relation to this Calendar. If any event is in
multiple calendars, the user has the following rights:
- The user may fetch the event if they have the mayReadItems
right on any calendar the event is in.
- The user may remove an event from a calendar (by modifying the
event's "calendarIds" property) if the user has the appropriate
permission for that calendar.
- The user may make other changes to the event if they have the
right to do so in _all_ calendars to which the event belongs.
A *CalendarRights* object has the following properties:
* *mayReadFreeBusy*: Boolean The user may read the free-busy
information for this calendar as part of a call to Principal/
getAvailability (see Section XXX).
* *mayReadItems*: Boolean The user may fetch the events in this
calendar.
* *mayWriteAll*: Boolean The user may create, modify or destroy all
events in this calendar, or move events to or from this calendar.
If this is true, the mayWriteOwn, mayUpdatePrivate and mayRSVP
properties MUST all also be true.
* *mayWriteOwn*: Boolean The user may create, modify or destroy an
event on this calendar if either they are the owner of the event
(see below) or the event has no owner. This means the user may
also transfer ownership by updating an event so they are no longer
an owner.
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* *mayUpdatePrivate*: Boolean The user may modify per-user
properties (see Section XXX) on all events in the calendar, even
if they would not otherwise have permission to modify that event.
These properties MUST all be stored per-user, and changes do not
affect any other user of the calendar.
The user may also modify these properties on a per-occurrence
basis for recurring events (updating the "recurrenceOverrides"
property of the event to do so).
* *mayRSVP*: Boolean The user may modify the following properties of
any Participant object that corresponds to one of the user's
ParticipantIdentity objects in the account, even if they would not
otherwise have permission to modify that event:
- participationStatus
- participationComment
- expectReply
- scheduleAgent
- scheduleSequence
- scheduleUpdated
If the event has its "mayInviteSelf" property set to true (see
Section XXX), then the user may also add a new Participant to the
event with scheduleId/sendTo properties that are the same as the
scheduleId/sendTo properties of one of the user's
ParticipantIdentity objects in the account. The roles property of
the participant MUST only contain "attendee".
If the event has its "mayInviteOthers" property set to true (see
Section XXX) and there is an existing Participant in the event
corresponding to one of the user's ParticipantIdentity objects in
the account, then the user may also add new participants. The
roles property of any new participant MUST only contain
"attendee".
The user may also do all of the above on a per-occurrence basis
for recurring events (updating the recurrenceOverrides property of
the event to do so).
* *mayAdmin*: Boolean The user may modify sharing for this calendar.
* *mayDelete*: Boolean (server-set) The user may delete the calendar
itself. This property MUST be false if the account to which this
calendar belongs has the _isReadOnly_ property set to true.
The user is an *owner* for an event if the CalendarEvent object has a
"participants" property, and one of the Participant objects both:
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a) Has the "owner" role.
b) Corresponds to one of the user's ParticipantIdentity objects in the account (as per Section XXX).
An event has no owner if its participants property is null or
omitted, or if none of the Participant objects have the "owner" role.
4.1. Calendar/get
This is a standard "/get" method as described in [RFC8620],
Section 5.1. The _ids_ argument may be null to fetch all at once.
If mayReadFreeBusy is the only permission the user has, the calendar
MUST NOT be returned in Calendar/get and Calendar/query; it must
behave as though it did not exist. The data is just used as part of
Principal/getAvailability.
4.2. Calendar/changes
This is a standard "/changes" method as described in [RFC8620],
Section 5.2.
4.3. Calendar/set
This is a standard "/set" method as described in [RFC8620],
Section 5.3 but with the following additional request arguments:
* *onDestroyRemoveEvents*: Boolean (default: false)
If false, any attempt to destroy a Calendar that still has
CalendarEvents in it will be rejected with a calendarHasEvent
SetError. If true, any CalendarEvents that were in the Calendar will
be removed from it, and if in no other Calendars they will be
destroyed. This SHOULD NOT send scheduling messages to participants
or create CalendarEventNotification objects.
* *onSuccessSetIsDefault*: Id|null If an id is given, and all
creates, updates and destroys (if any) succeed without error, the
server will try to set this calendar as the default. (For
references to Calendar creations, this is equivalent to a
creation-reference, so the id will be the creation id prefixed
with a "#".)
If the id is not found, or the change is not permitted by the server
for policy reasons, it MUST be ignored and the currently default
calendar (if any) will remain as such. No error is returned to the
client in this case.
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As per [RFC8620], Section 5.3, if the default is successfully
changed, any changed objects MUST be reported in either the "created"
or "updated" argument in the response as appropriate, with the
server-set value included.
The "shareWith" property may only be set by users that have the
mayAdmin right. When modifying the shareWith property, the user
cannot give a right to a principal if the principal did not already
have that right and the user making the change also does not have
that right. Any attempt to do so must be rejected with a forbidden
SetError.
Users can subscribe or unsubscribe to a calendar by setting the
"isSubscribed" property. The server MAY forbid users from
subscribing to certain calendars even though they have permission to
see them, rejecting the update with a forbidden SetError.
The following properties may be set by anyone who is subscribed to
the calendar and are always stored per-user:
* name
* color
* sortOrder
* isVisible
* timeZone
* includeInAvailability
* defaultAlertsWithoutTime
* defaultAlertsWithTime
The "name", "color", and "timeZone" properties are initially
inherited from the owner's copy of the calendar, but if set by a
sharee then they get their own copy of the property; it does not
change for any other principals. If the value of the property in the
owner's calendar changes after this, it does not overwrite the
sharee's value.
The "sortOrder", "isVisible", "includeInAvailability",
"defaultAlertsWithTime", and "defaultAlertsWithoutTime" properties
are initally the default value for each sharee; they are not
inherited from the owner.
The following extra SetError types are defined:
For "destroy":
* *calendarHasEvent*: The Calendar has at least one CalendarEvent
assigned to it, and the "onDestroyRemoveEvents" argument was
false.
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5. Calendar Events
A *CalendarEvent* object contains information about an event, or
recurring series of events, that takes place at a particular time.
It is a JSEvent object, as defined in [RFC8984], with the following
additional properties:
* *id*: Id (immutable; server-set) The id of the CalendarEvent. The
id uniquely identifies a JSEvent with a particular "uid" and
"recurrenceId" within a particular account.
* *baseEventId*: Id|null (immutable; server-set) This is only
defined if the _id_ property is a synthetic id, generated by the
server to represent a particular instance of a recurring event
(see Section XXX). This property gives the id of the "real"
CalendarEvent this was generated from.
* *calendarIds*: Id[Boolean] The set of Calendar ids this event
belongs to. An event MUST belong to one or more Calendars at all
times (until it is destroyed). The set is represented as an
object, with each key being a _Calendar id_. The value for each
key in the object MUST be true.
* *isDraft*: Boolean (default: false) If true, this event is to be
considered a draft. The server will not send any scheduling
messages to participants or send push notifications for alerts.
This may only be set to true upon creation. Once set to false,
the value cannot be updated to true. This property MUST NOT
appear in "recurrenceOverrides".
* *isOrigin*: Boolean (server-set) Is this the authoritative source
for this event (i.e., does it control scheduling for this event;
the event has not been added as a result of an invitation from
another calendar system)? This is true if, and only if:
- the event's "replyTo" property is null; or
- the account will receive messages sent to at least one of the
methods specified in the "replyTo" property of the event.
* *utcStart*: UTCDate For simple clients that do not or cannot
implement time zone support. Clients should only use this if also
asking the server to expand recurrences, as you cannot accurately
expand a recurrence without the original time zone.
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This property is calculated at fetch time by the server. Time
zones are political and they can and do change at any time.
Fetching exactly the same property again may return a different
results if the time zone data has been updated on the server.
Time zone data changes are not considered "updates" to the event.
If set, the server will convert the UTC date to the event's
current time zone and store the local time.
This is not included by default and must be requested explicitly.
Floating events (events without a time zone) will be interpreted
as per the time zone given as a CalendarEvent/get argument.
Note that it is not possible to accurately calculate the expansion
of recurrence rules or recurrence overrides with the utcStart
property rather than the local start time. Even simple
recurrences such as "repeat weekly" may cross a daylight-savings
boundary and end up at a different UTC time. Clients that wish to
use "utcStart" are RECOMMENDED to request the server expand
recurrences (see Section XXX).
* *utcEnd*: UTCDate The server calculates the end time in UTC from
the start/timeZone/duration properties of the event. This is not
included by default and must be requested explicitly. Like
utcStart, this is calculated at fetch time if requested and may
change due to time zone data changes. Floating events will be
interpreted as per the time zone given as a CalendarEvent/get
argument.
CalendarEvent objects MUST NOT have a "method" property as this is
only used when representing iTIP [RFC5546] scheduling messages, not
events in a data store.
5.1. Additional JSCalendar properties
This document defines three new JSCalendar properties for common use.
5.1.1. mayInviteSelf
Type: Boolean (default: false)
If true, any user may add themselves to the event as a participant
with the "attendee" role. This property MUST NOT be altered in the
recurrenceOverrides; it may only be set on the base object.
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This indicates the event will accept "party crasher" RSVPs via iTIP,
subject to any other domain-specific restrictions, and users may add
themselves to the event via JMAP as long as they have the mayRSVP
permission for the calendar.
5.1.2. mayInviteOthers
Type: Boolean (default: false)
If true, any current participant with the "attendee" role may add new
participants with the "attendee" role to the event. This property
MUST NOT be altered in the recurrenceOverrides; it may only be set on
the base object.
The mayRSVP permission for the calendar is also required in
conjunction with this event property for users to be allowed to make
this change via JMAP.
5.1.3. hideAttendees
Type: Boolean (default: false)
If true, only the owners of the event may see the full set of
participants. Other sharees of the event may only see the owners and
themselves. This property MUST NOT be altered in the
recurrenceOverrides; it may only be set on the base object.
5.2. Attachments
The Link object, as defined in [RFC8984] Section 4.2.7, with a "rel"
property equal to "enclosure" is used to represent attachments.
Instead of mandating an "href" property, clients may set a "blobId"
property instead to reference a blob of binary data in the account,
as per [RFC8620] Section 6.
The server MUST translate this to an embedded data: URL [RFC2397]
when sending the event to a system that cannot access the blob.
Servers that support CalDAV access to the same data are recommended
to expose these files as managed attachments [?@RFC8607].
5.3. Per-user properties
In shared calendars, any top-level property registered in the IANA
registry as "Is Per-User: yes" (see Section XXX) MUST be stored per-
user. This includes:
* keywords
* color
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* freeBusyStatus
* useDefaultAlerts
* alerts
The user may also modify these properties on a per-occurrence basis
for recurring events; again, these MUST be stored per-user. Sharees
initially receive the default value for each of these properties, not
whatever value another user may have set.
When writing only per-user properties, the "updated" property MUST
also be stored just for that user if set. When fetching the
"updated" property, the value to return is whichever is later of the
per-user updated time or the updated time of the base event.
5.4. Recurring events
Events may recur, in which case they represent multiple occurrences
or instances. The data store will either contain a single base
event, containing a recurrence rule and/or recurrence overrides; or,
a set of individual instances (when invited to specific occurrences
only).
The client may ask the server to expand recurrences within a specific
time range in "CalendarEvent/query". This will generate synthetic
ids representing individual instances in the requested time range.
The client can fetch and update the objects using these ids and the
server will make the appropriate changes to the base event.
Synthetic ids do not appear in "CalendarEvent/changes" responses;
only the ids of events as actually stored on the server.
If the user is invited to specific instances then later added to the
base event, "CalendarEvent/changes" will show the ids of all the
individual instances being destroyed and the id for the base event
being created.
5.5. Updating for "this-and-future"
When editing a recurring event, you can either update the base event
(affecting all instances unless overriden) or update an override for
a specific occurrence. To update all occurrences from a specific
point onwards, there are therefore two options: split the event, or
update the base event and override all occurrences before the split
point back to their original values.
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5.5.1. Splitting an event
If the event is not scheduled (has no participants), the simplest
thing to do is to duplicate the event, modifying the recurrence rules
of the original so it finishes before the split point, and the
duplicate so it starts at the split point. As per JSCalendar
[RFC8984] Section 4.1.3, a "next" and "first" relation MUST be set on
the new objects respectively.
Splitting an event however is problematic in the case of a scheduled
event, because the iTIP messages generated make it appear like two
unrelated changes, which can be confusing.
5.5.2. Updating the base event and overriding previous
For scheduled events, a better approach is to avoid splitting and
instead update the base event with the new property value for "this
and future", then create overrides for all occurrences before the
split point to restore the property to its previous value. Indeed,
this may be the only option the user has permission to do if not an
owner of the event.
Clients may choose to skip creating the overrides if the old data is
not important, for example if the "alerts" property is being updated,
it is probably not important to create overrides for events in the
past with the alerts that have already fired.
5.6. CalendarEvent/get
This is a standard "/get" method as described in [RFC8620],
Section 5.1, with three extra arguments:
* *recurrenceOverridesBefore*: UTCDate|null If given, only
recurrence overrides with a recurrence id before this date (when
translated into UTC) will be returned.
* *recurrenceOverridesAfter*: UTCDate|null If given, only recurrence
overrides with a recurrence id on or after this date (when
translated into UTC) will be returned.
* *reduceParticipants*: Boolean (default: false) If true, only
participants with the "owner" role or corresponding to the user's
participant identities will be returned in the "participants"
property of the base event and any recurrence overrides. If
false, all participants will be returned.
* *timeZone*: String (default "Etc/UTC") The time zone to use when
calculating the utcStart/utcEnd property of floating events. This
argument has no effect if those properties are not requested.
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A CalendarEvent object is a JSEvent object so may have arbitrary
properties. If the client makes a "CalendarEvent/get" call with a
null or omitted "properties" argument, all properties defined on the
JSEvent object in the store are returned, along with the "id",
"calendarIds", "isDraft", and "isOrigin" properties. The "utcStart"
and "utcEnd" computed properties are only returned if explicitly
requested. If either are requested, the "recurrenceOverrides"
property MUST NOT be requested (recurrence overrides cannot be
interpreted accurately with just the UTC times).
If specific properties are requested from the JSEvent and the
property is not present on the object in the server's store, the
server SHOULD return the default value if known for that property.
A requested id may represent a server-expanded single instance of a
recurring event if the client asked the server to expand recurrences
in "CalendarEvent/query". In such a case, the server will resolve
any overrides and set the appropriate "start" and "recurrenceId"
properties on the CalendarEvent object returned to the client. The
"recurrenceRule" and "recurrenceOverrides" properties MUST be
returned as null if requested for such an event.
An event with the same uid/recurrenceId may appear in different
accounts. Clients may coalesce the view of such events, but must be
aware that the data may be different in the different accounts due to
per-user properties, difference in permissions, etc.
The "hideAttendees" property of a JSEvent object allows the event
owner(s) to reduce the visibility of sharees into the set of
participants. If this is true, when a non-owner sharee fetches the
event, the server MUST only return participants with the "owner" role
or corresponding to the user's participant identities.
The "privacy" property of a JSEvent object allows the principal that
owns the calendar to override how sharees of the calendar see the
event. If set to "private", then when a sharee fetches the event the
server MUST only return properties that are:
* the basic time and metadata properties of the JSEvent object as
specified in [RFC8984], Section 4.4.3; or
* properties that are wholly derived from these permitted properties
(i.e., utcStart, utcEnd); or
* Additional CalendarEvent properties not derived from the JSEvent
data (i.e., id, baseEventId, calendarIds, isDraft, isOrigin).
If "privacy" is set to "secret", the server MUST behave as though the
event does not exist for all users other than the principal that owns
the calendar.
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5.7. CalendarEvent/changes
This is a standard "/changes" method as described in [RFC8620],
Section 5.2.
Synthetic ids generated by the server expanding recurrences in
"CalendarEvent/query" do not appear in "CalendarEvent/changes"
responses; only the ids of events as actually stored on the server.
5.8. CalendarEvent/set
This is a standard "/set" method as described in [RFC8620],
Section 5.3, with the following extra argument:
* *sendSchedulingMessages*: Boolean (default: false) If true then
any changes to scheduled events will be sent to all the
participants (if the server is the origin of the event) or back to
the origin (otherwise). If false, the changes only affect this
account and no scheduling messages will be sent.
An id may represent a server-expanded single instance of a recurring
event if the client asked the server to expand recurrences in
"CalendarEvent/query". When the synthetic id for such an instance is
given, the server MUST process an update as an update to the
recurrence override for that instance on the base event, and a
destroy as removing just that instance.
Clients MUST NOT send an update/destroy to both the base event and a
synthetic instance in a single "/set" request; the result of this is
undefined. Note however, a client may replace a series of explicit
instances (each with the same uid but a different recurrenceId
property) with the base event (same uid, no recurrenceId) in a single
"/set" call. (So the /set will destroy the existing instances and
create the new base event.) This will happen when someone is
initially invited to a specific instance or instances of a recurring
event, then later invited to the whole series.
If a property is set to null in a create/update, this is equivalent
to omitting/removing the property from the JSEvent object.
Servers MUST enforce the user's permissions as returned in the
"myRights" property of the Calendar objects and reject changes with a
forbidden SetError if not allowed.
The "privacy" property of a JSEvent object allows the principal to
override how sharees of the calendar see the event. If this is set
to "private", a sharee may not delete or update the event (even if
only modifying per-user properties); any attempt to modify such an
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event MUST be rejected with a forbidden SetError. If set to
"secret", the server MUST behave as though the event does not exist
for all users other than the principal that owns the calendar.
The "privacy" property MUST NOT be set to anything other than
"public" (the default) for events in a calendar that does not belong
to the user (e.g. a shared team calendar, or a calendar shared by
another user). The server MUST reject this with an invalidProperties
SetError.
If omitted on create, the server MUST set the following properties to
an appropriate value:
* @type
* uid
* created
If (and only if) the server is the origin of the event (i.e., the
event's "isOrigin" property is true), the "updated" property MUST be
set to the current time by the server whenever an event is created or
updated. If the client tries to set a value for this property it is
not an error, but it MUST be overridden and replaced with the
server's time. If the event is being created and the overridden
"updated" time is now earlier than a client-supplied "created" time,
the "created" time MUST also be overridden to the server's time. If
the server is not the origin of the event it MUST NOT automatically
set an "updated" time, as this can break correct processing of iTIP
messages.
Clients SHOULD NOT allow users to manually edit anything other than
per-user properties when the "isOrigin" property is false, even if
the calendar "myRights" allows them to do so. All other properties
may be overwritten when a future update arrives to this event from
the origin (i.e., via another iTIP REQUEST). Such updates may be
directly applied by the server, or applied at the user's request by a
client if it has access to the data through some other means (e.g.,
the client also has access to the user's email and can parse an iMIP
message).
When updating an event, if all of:
* a property has been changed other than "calendarIds", "isDraft",
"updated" or a per-user property (see Section XXX); and
* the server is the origin of the event (the "isOrigin" property is
true); and
* the "sequence" property is not explicitly set in the update, or
the given value is less than or equal to the current "sequence"
value on the server;
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then the server MUST increment the "sequence" value by one.
The "method" property MUST NOT be set. Any attempt to do so is
rejected with a standard invalidProperties SetError.
If "utcStart" is set, this is translated into a "start" property
using the server's current time zone information. It MUST NOT be set
in addition to a "start" property and it cannot be set inside
"recurrenceOverrides"; this MUST be rejected with an
invalidProperties SetError.
Similarly, the "utcEnd" property is translated into a "duration"
property if set. It MUST NOT be set in addition to a "duration"
property and it cannot be set inside "recurrenceOverrides"; this MUST
be rejected with an invalidProperties SetError.
The server does not automatically reset the "partipationStatus" or
"expectReply" properties of a Participant when changing other event
details. Clients should either be intelligent about whether the
change invalidates previous RSVPs, or ask the user whether to reset
them.
The server MAY enforce that all events have an owner, for example in
team calendars. If the user tries to create an event without
participants in such a calendar, the server MUST automatically add a
participant with the "owner" role corresponding to one of the user's
ParticipantIdentities (see Section XXX).
When creating an event with participants, or adding participants to
an event that previously did not have participants, the server MUST
set the "replyTo" property of the event if not present. Clients
SHOULD NOT set the "replyTo" property for events when the user adds
participants; the server is better positioned to add all the methods
it supports to receive replies.
5.8.1. Patching
The JMAP "/set" method allows you to update an object by sending a
patch, rather than having to supply the whole object. When doing so,
care must be taken if updating a property of a CalendarEvent where
the value is itself a PatchObject, e.g. inside "localizations" or
"recurrenceOverrides". In particular, you cannot add a property with
value null to the CalendarEvent using a direct patch on that
property, as this is interpreted instead as a patch to remove the
property.
This is more easily understood with an example. Suppose you have a
CalendarEvent object like so:
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{
"id": "123",
"title": "FooBar team meeting",
"start": "2018-01-08T09:00:00",
"recurrenceRules": [{
"@type": "RecurrenceRule",
"frequency": "weekly"
}],
"replyTo": {
"imip": "mailto:6489-4f14-a57f-c1@schedule.example.com"
},
"participants": {
"dG9tQGZvb2Jhci5xlLmNvbQ": {
"@type": "Participant",
"name": "Tom",
"email": "tom@foobar.example.com",
"scheduleId": "mailto:6489-4f14-a57f-c1@calendar.example.com",
"sendTo": {
"imip": "mailto:6489-4f14-a57f-c1@calendar.example.com"
},
"participationStatus": "accepted",
"roles": {
"attendee": true
}
},
"em9lQGZvb2GFtcGxlLmNvbQ": {
"@type": "Participant",
"name": "Zoe",
"email": "zoe@foobar.example.com",
"scheduleId": "mailto:zoe@foobar.example.com"
"sendTo": {
"imip": "mailto:zoe@foobar.example.com",
"other": "https://foobar.example.com/zoe/itip"
},
"participationStatus": "accepted",
"roles": {
"owner": true,
"attendee": true,
"chair": true
}
},
"recurrenceOverrides": {
"2018-03-08T09:00:00": {
"start": "2018-03-08T10:00:00",
"participants/dG9tQGZvb2Jhci5xlLmNvbQ/participationStatus":
"declined"
}
}
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}
}
In this example, Tom is normally going to the weekly meeting but has
declined the occurrence on 2018-03-08, which starts an hour later
than normal. Now, if Zoe too were to decline that meeting, she could
update the event by just sending a patch like so:
[[ "CalendarEvent/set", {
"accountId": "ue150411c",
"update": {
"123": {
"recurrenceOverrides/2018-03-08T09:00:00/
participants~1em9lQGZvb2GFtcGxlLmNvbQ~1participationStatus":
"declined"
}
}
}, "0" ]]
This patches the "2018-03-08T09:00:00" PatchObject in
recurrenceOverrides so that it ends up like this:
"recurrenceOverrides": {
"2018-03-08T09:00:00": {
"start": "2018-03-08T10:00:00",
"participants/dG9tQGZvb2Jhci5xlLmNvbQ/participationStatus":
"declined",
"participants/em9lQGZvb2GFtcGxlLmNvbQ/participationStatus":
"declined"
}
}
Now if Tom were to change his mind and remove his declined status
override (thus meaning he is attending, as inherited from the top-
level event), he might remove his patch from the overrides like so:
[[ "CalendarEvent/set", {
"accountId": "ue150411c",
"update": {
"123": {
"recurrenceOverrides/2018-03-08T09:00:00/
participants~1dG9tQGZvb2Jhci5xlLmNvbQ~1participationStatus": null
}
}
}, "0" ]]
However, if you instead want to remove Tom from this instance
altogether, you could not send this patch:
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[[ "CalendarEvent/set", {
"accountId": "ue150411c",
"update": {
"123": {
"recurrenceOverrides/2018-03-08T09:00:00/
participants~1dG9tQGZvb2Jhci5xlLmNvbQ": null
}
}
}, "0" ]]
This would mean remove the "participants/dG9tQGZvb2Jhci5xlLmNvbQ"
property at path "recurrenceOverrides" -> "2018-03-08T09:00:00"
inside the object; but this doesn't exist. We actually we want to
add this property and make it map to null. The client must instead
send the full object that contains the property mapping to null, like
so:
[[ "CalendarEvent/set", {
"accountId": "ue150411c",
"update": {
"123": {
"recurrenceOverrides/2018-03-08T09:00:00": {
"start": "2018-03-08T10:00:00",
"participants/em9lQGZvb2GFtcGxlLmNvbQ/participationStatus":
"declined"
"participants/dG9tQGZvb2Jhci5xlLmNvbQ": null
}
}
}
}, "0" ]]
5.8.2. Sending invitations and responses
If "sendSchedulingMessages" is true, the server MUST send appropriate
iTIP [RFC5546] scheduling messages after successfuly creating,
updating or destroying a calendar event.
When determining which scheduling messages to send, the server must
first establish whether it is the _origin_ of the event, as described
in the "isOrigin" property.
Messages are only sent to participants with a "scheduleAgent"
property set to "server" or omitted. If the effective
"scheduleAgent" property is changed:
* to "server" from something else: send messages to this participant
as though the event had just been created.
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* from "server" to something else: send messages to this participant
as though the event had just been destroyed.
* any other change: do not send any messages to this participant.
The server may send the scheduling message via any of the methods
defined on the sendTo property of a participant (if the server is the
origin) or the replyTo property of the event (otherwise) that it
supports. If no supported methods are available, the server MUST
reject the change with a noSupportedScheduleMethods SetError.
If the server is the origin of the event it MUST NOT send messages to
any participant where it will receive the message back in the same
account (i.e. it must not send messages to the owner of the calendar
the event is already on).
If sending via iMIP [RFC6047], the server MAY choose to only send
updates it deems "essential" to avoid flooding the recipient's email
with changes they do not care about. For example, changes to the
participation status of another participant, or changes to events
solely in the past may be omitted.
5.8.2.1. REQUEST
When the server is the origin for the event, a REQUEST message
([RFC5546], Section 3.2.2) is sent to all current participants
(except those corresponding to the owner of the calendar) if either:
* The event is being created; or
* Any non per-user property (see Section XXX) is updated on the
event (including adding/removing participants), except if just
modifying the recurrenceOverrides such that CANCEL messages are
generated (see the next section).
Note, if the only change is adding an additional instance (not
generated by the event's recurrence rule) to the recurrenceOverrides,
this MAY be handled via sending an ADD message ([RFC5546],
Section 3.2.4) for the single instance rather than a REQUEST message
for the base event. However, for interoperability reasons this is
not recommended due to poor support in the wild for this type of
message.
The server MUST ensure participants are only sent information about
recurrence instances they are added to when sending scheduling
messages for recurring events. If the participant is not invited to
the full recurring event but only individual instances, scheduling
messages MUST be sent for just those expanded occurrences
individually. If a participant is invited to a recurring event, but
removed via a recurrence override from a particular instance, any
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scheduling messages to this participant MUST return the instance as
"excluded" (if it matches a recurrence rule for the event) or omit
the instance entirely (otherwise).
If the event's "hideAttendees" property is set to true, the recipient
MUST be the only attendee in the message; all others are omitted.
5.8.2.2. CANCEL
When the server is the origin for the event, a CANCEL message
([RFC5546], Section 3.2.5) is sent if any of:
* A participant is removed from either the base event or a single
instance (the message is only sent to this participant; remaining
participants will get a REQUEST, as described above).
* The event is destroyed.
* An exclusion is added to recurrenceOverrides to remove an instance
generated by the event's recurrence rule.
* An additional instance (not generated by the event's recurrence
rule) is removed from the recurrenceOverrides.
In each of the latter 3 cases, the message is sent to all
participants (except those corresponding to the owner of the
calendar).
5.8.2.3. REPLY
When the server is _not_ the origin for the event, a REPLY message
([RFC5546], Section 3.2.3) is sent for every participant
corresponding to one of the user's ParticipantIdentitities in the
account if any of the following changes are made:
* The "participationStatus" property of the participant is changed,
either for the base event or a specific instance, to any value
other than "needs-action".
* The event is created and the participationStatus is not "needs-
action".
* The event is destroyed and the participationStatus was not "needs-
action".
If the participationStatus property is changed for just a single
instance of the event (i.e., set in recurrenceOverrides), the REPLY
message SHOULD be sent for just that recurrence id.
5.9. CalendarEvent/copy
This is a standard "/copy" method as described in [RFC8620],
Section 5.4.
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5.10. CalendarEvent/query
This is a standard "/query" method as described in [RFC8620],
Section 5.5, with two extra arguments:
* *expandRecurrences*: Boolean (default: false) If true, the server
will expand any recurring event. If true, the filter MUST be just
a FilterCondition (not a FilterOperator) and MUST include both a
before and after property. This ensures the server is not asked
to return an infinite number of results.
* *timeZone*: String The time zone for before/after filter
conditions (default: "Etc/UTC")
If expandRecurrences is true, a separate id will be returned for each
instance of a recurring event that matches the query. This synthetic
id is opaque to the client, but allows the server to resolve the id +
recurrence id for "/get" and "/set" operations. Otherwise, a single
id will be returned for matching recurring events that represents the
entire event.
There is no necessary correspondence between the ids of different
instances of the same expanded event.
The following additional error may be returned instead of the
"CalendarEvent/query" response:
cannotCalculateOccurrences: the server cannot expand a recurrence
required to return the results for this query.
5.10.1. Filtering
A *FilterCondition* object has the following properties:
* *inCalendars*: Id[]|null A list of calendar ids. An event must be
in ANY of these calendars to match the condition.
* *after*: LocalDate|null The end of the event, or any recurrence of
the event, in the time zone given as the timeZone argument, must
be after this date to match the condition.
* *before*: LocalDate|null The start of the event, or any recurrence
of the event, in the time zone given as the timeZone argument,
must be before this date to match the condition.
* *text*: String|null Looks for the text in the _title_,
_description_, _locations_ (matching name/description),
_participants_ (matching name/email) and any other textual
properties of the event or any recurrence of the event.
* *title*: String|null Looks for the text in the _title_ property of
the event, or the overridden _title_ property of a recurrence.
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* *description*: String|null Looks for the text in the _description_
property of the event, or the overridden _description_ property of
a recurrence.
* *location*: String|null Looks for the text in the _locations_
property of the event (matching name/description of a location),
or the overridden _locations_ property of a recurrence.
* *owner*: String|null Looks for the text in the name or email
fields of a participant in the _participants_ property of the
event, or the overridden _participants_ property of a recurrence,
where the participant has a role of "owner".
* *attendee*: String|null Looks for the text in the name or email
fields of a participant in the _participants_ property of the
event, or the overridden _participants_ property of a recurrence,
where the participant has a role of "attendee".
* *participationStatus*: Must match. If owner/attendee condition,
status must be of that participant. Otherwise any.
* *uid*: String The uid of the event is exactly the given string.
If expandRecurrences is true, all conditions must match against the
same instance of a recurring event for the instance to match. If
expandRecurrences is false, all conditions must match, but they may
each match any instance of the event.
If zero properties are specified on the FilterCondition, the
condition MUST always evaluate to true. If multiple properties are
specified, ALL must apply for the condition to be true (it is
equivalent to splitting the object into one-property conditions and
making them all the child of an AND filter operator).
The exact semantics for matching String fields is *deliberately not
defined* to allow for flexibility in indexing implementation, subject
to the following:
* Text SHOULD be matched in a case-insensitive manner.
* Text contained in either (but matched) single or double quotes
SHOULD be treated as a *phrase search*, that is a match is
required for that exact sequence of words, excluding the
surrounding quotation marks. Use \", \' and \\ to match a literal
", ' and \ respectively in a phrase.
* Outside of a phrase, white-space SHOULD be treated as dividing
separate tokens that may be searched for separately in the event,
but MUST all be present for the event to match the filter.
* Tokens MAY be matched on a whole-word basis using stemming (so for
example a text search for bus would match "buses" but not
"business").
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5.10.2. Sorting
The following properties MUST be supported for sorting:
* start
* uid
* recurrenceId
The following properties SHOULD be supported for sorting:
* created
* updated
5.11. CalendarEvent/queryChanges
This is a standard "/queryChanges" method as described in [RFC8620],
Section 5.6.
6. Alerts
Alerts may be specified on events as described in [RFC8984],
Section 4.5.
Alerts MUST only be triggered for events in calendars where the user
is subscribed.
When an alert with an "email" action is triggered, the server MUST
send an email to the user to notify them of the event. The contents
of the email is implementation specific. Clients MUST NOT perform an
action for these alerts.
When an alert with a "display" action is triggered, clients SHOULD
display an alert in a platform-appropriate manner to the user to
remind them of the event. Clients with a full offline cache of
events may choose to calculate when alerts should trigger locally.
Alternatively, they can subscribe to push events from the server.
6.1. Default alerts
If the "useDefaultAlerts" property of an event is true, the alerts
are taken from the "defaultAlertsWithTime" or
"defaultAlertsWithoutTime" property of all Calendars the event is in,
as described in Section XXX, rather than the "alerts" property of the
CalendarEvent.
When using default alerts, the "alerts" property of the event is
ignored except for the following:
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* The "acknowledged" time for an alert is stored here when a default
alert for the event is dismissed. The id of the alert MUST be the
same as the id of the default alert in the calendar. See
Section XXX on acknowledging alerts.
* If an alert has a relatedTo property where the parent is the id of
one of the calendar default alerts, it is processed as normal and
not ignored. This is to support snoozing default alerts; see
Section XXX.
6.2. Acknowledging an alert
To dismiss an alert, clients set the "acknowledged" property of the
Alert object to the current date-time. If the alert was a calendar
default, it may need to be added to the event at this point in order
to acknowledge it. When other clients fetch the updated
CalendarEvent they SHOULD automatically dismiss or suppress duplicate
alerts (alerts with the same alert id that triggered on or before the
"acknowledged" date-time) and alerts that have been removed from the
event.
Setting the "acknowledged" property MUST NOT create a new recurrence
override. For a recurring calendar object, the "acknowledged"
property of the parent object MUST be updated, unless the alert is
already overridden in the "recurrenceOverrides" property.
6.3. Snoozing an alert
Users may wish to dismiss an alert temporarily and have it come back
after a specific period of time. To do this, clients MUST:
1. Acknowledge the alert as described in Section XXX.
2. Add a new alert to the event with an AbsoluteTrigger for the
date-time the alert has been snoozed until. Add a "relatedTo"
property to the new alert, setting the "parent" relation to point
to the original alert. This MUST NOT create a new recurrence
override; it is added to the same "alerts" property that contains
the alert that was acknowledged in step 1.
When acknowledging a snoozed alert (i.e. one with a parent relatedTo
pointing to the original alert), the client SHOULD delete the alert
rather than setting the "acknowledged" property.
6.4. Push events
Servers that support the urn:ietf:params:jmap:calendars capability
MUST support registering for the pseudo-type "CalendarAlert" in push
subscriptions and event source connections, as described in
[RFC8620], Sections 7.2 and 7.3.
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If requested, a CalendarAlert notification will be pushed whenever an
alert is triggered for the user. For Event Source connections, this
notification is pushed as an event called "calendarAlert".
A *CalendarAlert* object has the following properties:
* *@type*: String This MUST be the string "CalendarAlert".
* *accountId*: Id The account id for the calendar in which the alert
triggered.
* *calendarEventId*: Id The CalendarEvent id for the alert that
triggered. Note, for a recurring event this is the id of the base
event, never a synthetic id for a particular instance.
* *uid*: String The uid property of the CalendarEvent for the alert
that triggered.
* *recurrenceId*: LocalDate|null The recurrenceId for the instance
of the event for which this alert is being triggered, or null if
the event is not recurring.
* *alertId*: String The id for the alert that triggered.
7. Calendar Event Notifications
The CalendarEventNotification data type records changes made by
external entities to events in calendars the user is subscribed to.
Notifications are stored in the same Account as the CalendarEvent
that was changed.
Notifications are only created by the server; users cannot create
them directly. Clients SHOULD present the list of notifications to
the user and allow them to dismiss them. To dismiss a notification
you use a standard "/set" call to destroy it.
The server SHOULD create a CalendarEventNotification whenever an
event is added, updated or destroyed by another user or due to
receiving an iTIP [RFC5546] or other scheduling message in a calendar
this user is subscribed to. The server SHOULD NOT create
notifications for events implicitly deleted due to the containing
calendar being deleted.
The CalendarEventNotification does not have any per-user data. A
single instance may therefore be maintained on the server for all
sharees of the notification. The server need only keep track of
which users have yet to destroy the notification.
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7.1. Auto-deletion of Notifications
The server MAY limit the maximum number of notifications it will
store for a user. When the limit is reached, any new notification
will cause the previously oldest notification to be automatically
deleted.
The server MAY coalesce events if appropriate, or remove events that
it deems are no longer relevant or after a certain period of time.
The server SHOULD automatically destroy a notification about an event
if the user updates or destroys that event (e.g. if the user sends an
RSVP for the event).
7.2. Object Properties
The *CalendarEventNotification* object has the following properties:
* *id*: String The id of the CalendarEventNotification.
* *created*: UTCDate The time this notification was created.
* *changedBy*: Person Who made the change. The Person object has
the following properties:
- *name*: String The name of the person who made the change.
- *email*: String|null The email of the person who made the
change, or null if no email is available.
- *principalId*: String|null The id of the Principal
corresponding to the person who made the change, if any. This
will be null if the change was due to receving an iTIP message.
- *scheduleId*: String|null The scheduleId URI of the person who
made the change, if any. This will normally be set if the
change was made due to receving an iTIP message.
* *comment*: String|null Comment sent along with the change by the
user that made it. (e.g. COMMENT property in an iTIP message), if
any.
* *type*: String This MUST be one of
- created
- updated
- destroyed
* *calendarEventId*: String The id of the CalendarEvent that this
notification is about.
* *isDraft*: Boolean (created/updated only) Is this event a draft?
* *event*: JSEvent The data before the change (if updated or
destroyed), or the data after creation (if created).
* *eventPatch*: PatchObject (updated only) A patch encoding the
change between the data in the event property, and the data after
the update.
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If the change only affects a single instance of a recurring event,
the server MAY set the event and eventPatch properties for just that
instance; the calendarEventId MUST still be for the base event.
7.3. CalendarEventNotification/get
This is a standard "/get" method as described in [RFC8620],
Section 5.1.
7.4. CalendarEventNotification/changes
This is a standard "/changes" method as described in [RFC8620],
Section 5.2.
7.5. CalendarEventNotification/set
This is a standard "/set" method as described in [RFC8620],
Section 5.3.
Only destroy is supported; any attempt to create/update MUST be
rejected with a forbidden SetError.
7.6. CalendarEventNotification/query
This is a standard "/query" method as described in [RFC8620],
Section 5.5.
7.6.1. Filtering
A *FilterCondition* object has the following properties:
* *after*: UTCDate|null The creation date must be on or after this
date to match the condition.
* *before*: UTCDate|null The creation date must be before this date
to match the condition.
* *type*: String The type property must be the same to match the
condition.
* *calendarEventIds*: Id[]|null A list of event ids. The
calendarEventId property of the notification must be in this list
to match the condition.
7.6.2. Sorting
The "created" property MUST be supported for sorting.
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7.7. CalendarEventNotification/queryChanges
This is a standard "/queryChanges" method as described in [RFC8620],
Section 5.6.
8. Examples
For brevity, in the following examples only the "methodCalls"
property of the Request object, and the "methodResponses" property of
the Response object is shown.
8.1. Fetching initial data
A user has authenticated and the client has fetched the JMAP Session
object. It finds a single Account with the
"urn:ietf:params:jmap:calendars" capability, with id "a0x9", and
wants to display all the calendar information for January 2023 in the
Australia/Melbourne time zone. It might make the following request:
[
["Calendar/get", {
"accountId": "a0x9"
}, "0"],
["ParticipantIdentity/get", {
"accountId": "a0x9"
}, "1"],
["CalendarEvent/query", {
"accountId": "a0x9",
"timeZone": "Australia/Melbourne",
"filter": {
"after": "2023-01-01T00:00:00",
"before": "2023-02-01T00:00:00"
}
}, "2"],
["CalendarEvent/get", {
"accountId": "a0x9",
"#ids":{
"resultOf":"3",
"name":"CalendarEvent/query",
"path":"/ids"
}
}, "3"]
]
The server might respond with something like:
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[
["Calendar/get", {
"accountId": "a0x9",
"list": [{
"id": "062adcfa-105d-455c-bc60-6db68b69c3f3",
"name": "Private",
"sortOrder": 12
"isDefault": false,
"defaultAlertsWithTime": null,
...
}, {
"id": "3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662",
"name": "Work",
"sortOrder": 4
"isDefault": true,
"defaultAlertsWithTime": {
"631BE24C-A3B6-11EC-BF4C-B027680D752E": {
"@type": "Alert",
"action": "display",
"trigger": {
"@type": "OffsetTrigger",
"offset": "-PT1H",
"relativeTo": "start"
}
}
},
...
}],
"notFound": [],
"state": "~506"
}, "0"],
["ParticipantIdentity/get", {
"accountId": "a0x9",
"list": [{
"id": "3",
"name": "Jane Doe"
"scheduleId": "mailto:jane@example.com",
"sendTo": {
"imip": "mailto:jane@example.com",
"other":
"https://example.com/uri/for/internal/scheduling"
},
"isDefault": true
}],
"notFound": [],
"state": "lgkf:98144:aae"
}, "1"],
["CalendarEvent/query", {
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"accountId": "a0x9",
"canCalculateChanges": false,
"position": 0,
"queryState": "~206",
"ids": [
"E-01c9626e-1490-43df-a34f-457021256281",
"E-07a2b89d-96b6-4920-982a-54fdf0a386ce",
...
]
}, "2"],
["CalendarEvent/get", {
"accountId": "a0x9",
"list": [{
"id": "E-01c9626e-1490-43df-a34f-457021256281",
"calendarIds": {
"3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662": true,
},
"title": "Q1 All hands"
"start": "20230109T10:00:00",
"duration": "PT1H",
"timeZone": "Australia/Sydney",
...
}, ...],
"notFound": [],
"state": "$$/413/206"
}, "3"]
]
The client now has everything it needs to display that month in full.
8.2. Creating an event
Suppose the user asks the client to create a new event. The client
should default to adding it to the "Work" calendar, as this is the
default calendar for the user, unless it has information to make a
more informed decision. (e.g. The client may have a feature to
automatically choose the calendar based on the time of day, and the
user indicates the event is at 7pm, so it knows to default to
"Private".)
[
["CalendarEvent/set", {
"accountId":"a0x9",
"create":{
"k559":{
"uid":"5d5776f6-ff8e-4bfd-ab3e-fe2fe5d4fa91",
"calendarIds":{
"3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662":true
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},
"title":"Party at Pete’s",
"start":"2023-02-03T19:00:00",
"duration":"PT3H0M0S",
"timeZone":"Australia/Melbourne",
"showWithoutTime":false,
"participants":{
"1":{
"@type":"Participant",
"name": "Jane Doe"
"scheduleId": "mailto:jane@example.com",
"sendTo": {
"imip": "mailto:jane@example.com",
"other":
"https://example.com/uri/for/internal/scheduling"
}
"kind":"individual",
"roles":{
"attendee":true,
"owner":true
},
"participationStatus":"accepted",
"expectReply":false
},
"2":{
"@type":"Participant",
"name":"Joe Bloggs",
"sendTo":{
"imip":"mailto:joe@example.com"
},
"kind":"individual",
"roles":{
"attendee":true
},
"participationStatus":"needs-action",
"expectReply":true
}
},
"mayInviteSelf":false,
"mayInviteOthers":false,
"useDefaultAlerts":false,
"alerts":null
}
},
"sendSchedulingMessages":true
}, "0"]
]
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As the event has participants, the server sets a "replyTo" property.
This server uses a special email address for receiving iTIP RSVPs
rather than just receiving them at the owner's regular email address,
and also provides a web page for people that don't have calendar
clients supporting iTIP. The response may look something like this:
[
["CalendarEvent/set", {
"accountId":"a0x9",
"created":{
"k559":{
"id":"E-5d5776f6-ff8e-4bfd-ab3e-fe2fe5d4fa91",
"isOrigin": true,
"@type": "Event",
"created": "20221005T20:42:13Z",
"updated": "20221005T20:42:13Z",
"sequence": 1,
"replyTo": {
"imip": "3e87-1b18bb5e6b4@itip.example.com",
"web": https://cal.example.com/
5d5776f6-ff8e-4bfd-ab3e-fe2fe5d4fa91/?
auth=bfc0-4ba3-9e44"
}
}
},
...
}, "0"]
]
8.3. Snoozing an alert
The client is connected to the event source and receives a push:
{
"@type": "CalendarAlert",
"accountId": "a0x9",
"calendarEventId": "E-7e93e3ee-4e6e-408a-9adc-cbaf1dbd0a3f",
"uid": "b6f7e27b-5872-4b52-b457-0242541bb01c",
"recurrenceId": null,
"alertId": "7519a951-1e6f-4a6c-b08b-20dd2e5a89cd"
}
Not finding this event in its local cache, the client fetches the
information for this event that it needs to show the alert by making
the following request:
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[
["CalendarEvent/get", {
"accountId": "a0x9",
"ids":["E-7e93e3ee-4e6e-408a-9adc-cbaf1dbd0a3f"],
"properties": ["calendarIds", title", "start",
"timeZone", "useDefaultAlerts", "alerts"]
}, "0"]
]
In response it receives:
[
["CalendarEvent/get", {
"accountId": "a0x9",
"list": [{
"id": "E-01c9626e-1490-43df-a34f-457021256281",
"calendarIds": {
"3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662": true,
},
"title": "Team catchup"
"start": "20230210T17:00:00",
"timeZone": "America/New_York",
"useDefaultAlerts": false,
"alerts": {
"7519a951-1e6f-4a6c-b08b-20dd2e5a89cd": {
"@type": "Alert",
"action": "display",
"trigger": {
"@type": "OffsetTrigger",
"relativeTo": "start",
"offset": "-PT1H"
}
}
}
}],
"notFound": [],
"state": "$$/414/208"
}, "0"]
]
The client displays an alert in a platform-appropriate manner.
Presuming the user here is in the Australia/Melbourne time zone, this
might look something like:
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+----------------------------------------+
| |
| Reminder: Team catchup |
| Today at 10am (in 1 hour) |
| [Snooze\/] |
+----------------------------------------+
The user snoozes the notification for 30 minutes. The client
dismisses the current notification and sends an update to the event
to the server:
[
["CalendarEvent/set", {
"accountId": "a0x9",
"update": {
"E-01c9626e-1490-43df-a34f-457021256281": {
"alerts/7519a951-1e6f-4a6c-b08b-20dd2e5a89cd
/acknowledged": "20230110T23:00:31Z",
"alerts/86b0-318b8291045f": {
"@type": "Alert",
"action": "display",
"trigger": {
"@type": "AbsoluteTrigger",
"when": "20230210T23:30:00Z",
"relatedTo": {
"7519a951-1e6f-4a6c-b08b-20dd2e5a89cd": {
"@type": "Relation",
"relation": {
"parent": true,
}
}
}
}
}
}
}
}, "0"]
]
Any other connected client will receive a push, sync the change and
dismiss any duplicate alert. After the snooze time has elapsed, the
new alert will trigger.
8.4. Changing the default calendar
The client tries to change the default calendar from "Work" to
"Private" (and makes no other change):
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[
["Calendar/set", {
"accountId": "a0x9",
"onSuccessSetIsDefault": "062adcfa-105d-455c-bc60-6db68b69c3f3"
}, "0"]
]
The server allows the change, returning the following response:
[
["Calendar/set", {
"accountId": "a0x9",
"updated": {
"062adcfa-105d-455c-bc60-6db68b69c3f3": {
"isDefault": true,
},
"3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662": {
"isDefault": false,
}
}, "0"]
]
9. Security Considerations
All security considerations of JMAP [RFC8620] and JSCalendar
[RFC8984] apply to this specification. Additional considerations
specific to the data types and functionality introduced by this
document are described in the following subsections.
9.1. Privacy
Calendars often contain the precise movements, activities, and
contacts of people; all intensely private data. Privacy leaks can
have real world consequences, and calendar servers and clients MUST
be mindful of the need to keep all data secure.
Servers MUST enforce the ACLs set on calendars to ensure only
authorised data is shared. The additional restrictions specified by
the "privacy" property of a JSEvent object (see [RFC8984]
Section 4.4.3) MUST also be enforced.
Users may have multiple Participant Identities that they use for
areas of their life kept private from one another. Using one
identity with an event MUST NOT leak the existence of any other
identity. For example, sending an RSVP from identity
worklife@example.com MUST NOT reveal anything about another identity
present in the account such as privatelife@example.org.
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Severs SHOULD enforce that invitations sent to external systems are
only transmitted via secure encrypted and signed connections to
protect against eavesdropping and modification of data.
9.2. Spoofing
When receiving events and updates from external systems, it can be
hard to verify that the identity of the author is who they claim to
be. When receiving events via email, DKIM [RFC6376] and S/MIME
[RFC8551] are two mechanisms that may be used to verify certain
properties about the email data, which can be correlated with the
event information.
9.3. Denial-of-service
There are many ways in which a calendar user can make a request
liable to cause a calendar server to spend an inordinate amount of
processing time. Care must be taken to limit resources allocated to
any one user to ensure the system does not become unresponsive. The
following subsections list particularly hazardous areas.
9.3.1. Expanding Recurrences
Recurrence rules can be crafted to occur as frequently as every
second. Servers MUST be careful to not allow resources to be
exhausted when expanding, and limit the number of expansions they
will create. Equally, rules can be generated that never create any
occurrences at all. Servers MUST be careful to limit the work spent
iterating in search of the next occurrence.
9.3.2. Firing alerts
An alert firing for an event can cause a notification to be pused to
the user's devices, or to send them an email. Servers MUST rate
limit the number of alerts sent for any one user. The combination of
recurring events with multiple alerts can in particular define
unreasonably frequent alerts, leading to denial of service for either
the server processing them or the user's devices receiving them.
Similarly, clients generating alerts from the data on device must
take the same precautions.
The "email" alert type (see RFC8984, Section 4.5.2) causes an email
to be sent when triggered. Clients MUST ignore this alert type; the
email is sent only be the calendar server. There is no mechanism in
JSCalendar to specify a particular email address: the server MUST
only allow alerts to be sent to an address it has verified as
belonging to the user to avoid this being used as a spamming vector.
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9.3.3. Load spikes
Since most events are likely to start on the hour mark, a large spike
of activity is often seen at these times, with particularly large
spikes at certain common times in the time zone of the server's user
base. In particular, a large number of alerts (across different
users and events) will be triggered at the same time. Servers may
mitigate this somewhat by adding jitter to the triggering of the
alerts; it is RECOMMENDED to fire them slightly early rather than
slightly late if needed to spread load.
9.4. Spam
Invitations received from an untrusted source may be spam. If this
is added to the user's calendar automatically it can be very
obtrusive, especially if it is a recurring event that now appears
every day. Incoming invitations to events should be subject to spam
scanning, and suspicious events should not be added to the calendar
automatically.
Servers should strip any alerts on invitations when adding to the
user's calendar; the useDefaultAlerts property should be set instead
to apply the user's preferences.
Similarly, a malicious user may use a calendar system to send spam by
inviting people to an event. Outbound iTIP should be subject to all
the same controls used on outbound email systems, and rate limited as
appropriate. A rate limit on the number of distinct recipients as
well as overall messages is recommended.
10. IANA Considerations
10.1. JMAP Capability Registration for "calendars"
IANA will register the "calendars" JMAP Capability as follows:
Capability Name: urn:ietf:params:jmap:calendars
Specification document: this document
Intended use: common
Change Controller: IETF
Security and privacy considerations: this document, Section XXX
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10.2. JMAP Capability Registration for "principals:availability"
IANA will register the "principals:availability" JMAP Capability as
follows:
Capability Name: urn:ietf:params:jmap:principals:availability
Specification document: this document
Intended use: common
Change Controller: IETF
Security and privacy considerations: this document, Section XXX
10.3. Update to the JSCalendar Properties Registry
IANA will update the "JSCalendar Properties" registry to add a new
column called "Is Per-User". The value in this column for each entry
MUST be either "yes" or "no", indicating whether each sharee of the
object should be able to set their own value for this property
without affecting the value for other sharees.
10.3.1. Update to "JSCalendar Properties" Registry Template
An additional field is added to the template:
Is Per-User
10.3.2. Initial values for existing registrations
IANA will set "Is per-user: yes" on the following property
registrations:
* keywords
* color
* freeBusyStatus
* useDefaultAlerts
* alerts
All other existing registrations will have "Is per-user: no".
10.4. JSCalendar Property Registrations
IANA will register the following additional properties in the
JSCalendar Properties Registry.
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10.4.1. id
Property Name: id
Property Type: Id
Property Context: JSEvent, JSTask
Intended Use: Reserved
Is per-user: no
10.4.2. baseEventId
Property Name: baseEventId
Property Type: Id|null
Property Context: JSEvent, JSTask
Intended Use: Reserved
Is per-user: no
10.4.3. calendarIds
Property Name: calendarIds
Property Type: Id[Boolean]
Property Context: JSEvent, JSTask
Intended Use: Reserved
Is per-user: no
10.4.4. isDraft
Property Name: isDraft
Property Type: Boolean
Property Context: JSEvent, JSTask
Intended Use: Reserved
Is per-user: no
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10.4.5. isOrigin
Property Name: isOrigin
Property Type: Boolean
Property Context: JSEvent, JSTask
Intended Use: Reserved
Is per-user: no
10.4.6. utcStart
Property Name: utcStart
Property Type: UTCDateTime
Property Context: JSEvent, JSTask
Intended Use: Reserved
Is per-user: no
10.4.7. utcEnd
Property Name: utcEnd
Property Type: UTCDateTime
Property Context: JSEvent, JSTask
Intended Use: Reserved
Is per-user: no
10.4.8. mayInviteSelf
Property Name: mayInviteSelf
Property Type: Boolean (default: false)
Property Context: JSEvent, JSTask
Reference: This document, Section XXX.
Intended Use: Common
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Is per-user: no
10.4.9. mayInviteOthers
Property Name: mayInviteOthers
Property Type: Boolean (default: false)
Property Context: JSEvent, JSTask
Reference: This document, Section XXX.
Intended Use: Common
Is per-user: no
10.4.10. hideAttendees
Property Name: hideAttendees
Property Type: Boolean (default: false)
Property Context: JSEvent, JSTask
Reference: This document, Section XXX.
Intended Use: Common
Is per-user: no
11. 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>.
[RFC2397] Masinter, L., "The "data" URL scheme", RFC 2397,
DOI 10.17487/RFC2397, August 1998,
<https://www.rfc-editor.org/info/rfc2397>.
[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>.
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[RFC6376] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed.,
"DomainKeys Identified Mail (DKIM) Signatures", STD 76,
RFC 6376, DOI 10.17487/RFC6376, September 2011,
<https://www.rfc-editor.org/info/rfc6376>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8551] Schaad, J., Ramsdell, B., and S. Turner, "Secure/
Multipurpose Internet Mail Extensions (S/MIME) Version 4.0
Message Specification", RFC 8551, DOI 10.17487/RFC8551,
April 2019, <https://www.rfc-editor.org/info/rfc8551>.
[RFC8620] Jenkins, N. and C. Newman, "The JSON Meta Application
Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July
2019, <https://www.rfc-editor.org/info/rfc8620>.
[RFC8984] Jenkins, N. and R. Stepanek, "JSCalendar: A JSON
Representation of Calendar Data", RFC 8984,
DOI 10.17487/RFC8984, July 2021,
<https://www.rfc-editor.org/info/rfc8984>.
12. Informative References
[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>.
[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>.
[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>.
Authors' Addresses
Neil Jenkins (editor)
Fastmail
PO Box 234, Collins St West
Melbourne VIC 8007
Australia
Email: neilj@fastmailteam.com
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URI: https://www.fastmail.com
Michael Douglass (editor)
Spherical Cow Group
226 3rd Street
Troy, NY 12180
United States of America
Email: mdouglass@sphericalcowgroup.com
URI: http://sphericalcowgroup.com
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