draft-ietf-calext-availability-00.txt   draft-ietf-calext-availability-01.txt 
Network Working Group C. Daboo Network Working Group C. Daboo
Internet-Draft Apple Internet-Draft Apple
Updates: 5545,5546 (if approved) M. Douglass Intended status: Standards Track M. Douglass
Intended status: Standards Track RPI Expires: May 26, 2016 RPI
Expires: September 24, 2015 March 23, 2015 November 23, 2015
Calendar Availability Calendar Availability
draft-ietf-calext-availability-00 draft-ietf-calext-availability-01
Abstract Abstract
This document specifies a new iCalendar calendar component that This document specifies a new iCalendar calendar component that
allows the publication of available and unavailable time periods allows the publication of available and unavailable time periods
associated with a calendar user. This component can be used in associated with a calendar user. This component can be used in
standard iCalendar free-busy lookups, including iTIP free-busy standard iCalendar free-busy lookups, including iTIP free-busy
requests, to generate repeating blocks of available or busy time with requests, to generate repeating blocks of available or busy time with
exceptions as needed. exceptions as needed.
This document also defines extensions to CalDAV calendar-access and This document also defines extensions to CalDAV calendar-access and
calendar-auto-schedule which specify how this new calendar component calendar-auto-schedule which specify how this new calendar component
should be used when doing free-busy time evaluation in CalDAV. can be used when doing free-busy time evaluation in CalDAV.
Editorial Note (To be removed by RFC Editor before publication) Editorial Note (To be removed by RFC Editor before publication)
Discussion of this specification is taking place on the mailing list Discussion of this specification is taking place on the mailing list
http://lists.osafoundation.org/mailman/listinfo/ietf-caldav . http://lists.osafoundation.org/mailman/listinfo/ietf-caldav .
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
skipping to change at page 1, line 45 skipping to change at page 1, line 45
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 24, 2015. This Internet-Draft will expire on May 26, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 25 skipping to change at page 2, line 25
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 3 2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. iCalendar Extensions . . . . . . . . . . . . . . . . . . . . 4 3. iCalendar Extensions . . . . . . . . . . . . . . . . . . . . 4
3.1. Vavailability Component . . . . . . . . . . . . . . . . . 4 3.1. VAVAILABILITY Component . . . . . . . . . . . . . . . . . 4
3.2. Busy Time Type . . . . . . . . . . . . . . . . . . . . . 10 3.2. Busy Time Type . . . . . . . . . . . . . . . . . . . . . 10
4. Combining Vavailability components . . . . . . . . . . . . . 10 4. Combining VAVAILABILITY components . . . . . . . . . . . . . 10
5. Calculating Free-Busy Time . . . . . . . . . . . . . . . . . 11 5. Calculating Free-Busy Time . . . . . . . . . . . . . . . . . 11
5.1. Examples . . . . . . . . . . . . . . . . . . . . . . . . 12 5.1. Examples . . . . . . . . . . . . . . . . . . . . . . . . 12
6. CalDAV Extensions . . . . . . . . . . . . . . . . . . . . . . 14 6. Use with iTIP . . . . . . . . . . . . . . . . . . . . . . . . 14
6.1. CalDAV Requirements Overview . . . . . . . . . . . . . . 14 7. CalDAV Extensions . . . . . . . . . . . . . . . . . . . . . . 14
6.2. New features in CalDAV . . . . . . . . . . . . . . . . . 15 7.1. CalDAV Requirements Overview . . . . . . . . . . . . . . 14
7. Security Considerations . . . . . . . . . . . . . . . . . . . 18 7.2. New features in CalDAV . . . . . . . . . . . . . . . . . 15
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
8.1. Component Registrations . . . . . . . . . . . . . . . . . 18 9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 18
8.2. Property Registrations . . . . . . . . . . . . . . . . . 18 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 10.1. Component Registrations . . . . . . . . . . . . . . . . 18
10. Normative References . . . . . . . . . . . . . . . . . . . . 18 10.2. Property Registrations . . . . . . . . . . . . . . . . . 19
Appendix A. Example Calendar #1 . . . . . . . . . . . . . . . . 19 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19
12. Normative References . . . . . . . . . . . . . . . . . . . . 19
Appendix A. Example Calendar #1 . . . . . . . . . . . . . . . . 20
Appendix B. Change History (To be removed by RFC Editor before Appendix B. Change History (To be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 21 publication) . . . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction 1. Introduction
Often calendar users have regular periods of time when they are Calendar users often have regular periods of time when they are
either available to be scheduled or always unavailable. For example, either available to be scheduled or always unavailable. For example,
an office worker will often wish to only appear free to their work an office worker will often wish only to appear free to their work
colleagues during normal 'office hours' (e.g., Monday through Friday, colleagues during normal 'office hours' (e.g., Monday through Friday,
9 am through 5 pm). Or, a university professor may only be available 9 am through 5 pm). Or, a university professor might only be
to students during a set period of time (e.g., Thursday afternoons, 2 available to students during a set period of time (e.g., Thursday
pm through 5 pm during term time only). Ideally users should be able afternoons, 2 pm through 5 pm during term time only). Ideally users
to specify such periods directly via their calendar user agent, and ought be able to specify such periods directly via their calendar
have them automatically considered as part of the normal free-busy user agent, and have them automatically considered as part of the
lookup for that user. In addition it should be possible to present normal free-busy lookup for that user. In addition, it ought be
different periods of available time depending on which user is making possible to present different periods of available time depending on
the request. which user is making the request.
iCalendar [RFC5545] defines a "VFREEBUSY" component that can be used iCalendar [RFC5545] defines a "VFREEBUSY" component that can be used
to represent fixed busy time periods, but it does does not provide a to represent fixed busy time periods, but it does not provide a way
way to specify a repeating period of available or unavailable time. to specify a repeating period of available or unavailable time.
Since repeating patterns are often the case, "VFREEBUSY" components Since repeating patterns are often the case, "VFREEBUSY" components
are not sufficient to solve this problem. are not sufficient to solve this problem.
This specification defines a new type of iCalendar calendar component This specification defines a new type of iCalendar component that can
that can be used to publish user availability. be used to publish user availability.
CalDAV [RFC4791] provides a way for calendar users to access and CalDAV [RFC4791] provides a way for calendar users to access and
manage calendar data and exchange this data via scheduling manage calendar data and exchange this data via scheduling
operations. As part of this, the CalDAV calendar-access [RFC4791] operations. As part of this, the CalDAV calendar-access [RFC4791]
feature provides a CALDAV:free-busy-query REPORT that returns free- feature provides a CALDAV:free-busy-query REPORT that returns free-
busy information for a calendar collection or hierarchy of calendar busy information for a calendar collection or hierarchy of calendar
collections. Also, the CalDAV calendar-auto-schedule [RFC6638] collections. Also, the CalDAV calendar-auto-schedule [RFC6638]
feature allows free-busy information for a calendar user to be feature allows free-busy information for a calendar user to be
determined. Both of these operations involve examining user determined. Both of these operations involve examining user
calendars for events that 'block time', with the blocked out periods calendars for events that 'block time', with the blocked out periods
skipping to change at page 3, line 41 skipping to change at page 3, line 43
calendar-auto-schedule features to allow the new iCalendar calendar-auto-schedule features to allow the new iCalendar
availability components to be stored and manipulated, and to allow availability components to be stored and manipulated, and to allow
free-busy lookups to use the information from any such components, if free-busy lookups to use the information from any such components, if
present. present.
2. Conventions Used in This Document 2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
[RFC2119] . [RFC2119].
When XML element types in the namespaces "DAV:" and When XML element types in the namespaces "DAV:" and
"urn:ietf:params:xml:ns:caldav" are referenced in this document "urn:ietf:params:xml:ns:caldav" are referenced in this document
outside of the context of an XML fragment, the string "DAV:" and outside of the context of an XML fragment, the string "DAV:" and
"CALDAV:" will be prefixed to the element type names respectively. "CALDAV:" will be prefixed to the element type names respectively.
3. iCalendar Extensions 3. iCalendar Extensions
This specification adds a new "VAVAILABILITY" calendar component to This specification adds a new "VAVAILABILITY" calendar component to
iCalendar. The "VAVAILABILITY" component is itself a container for iCalendar. The "VAVAILABILITY" component is itself a container for
new "AVAILABLE" sub-components. new "AVAILABLE" sub-components.
The purpose of the "VAVAILABILITY" calendar component is to provide a The purpose of the "VAVAILABILITY" calendar component is to provide a
grouping of available time information over a specific range of time. grouping of available time information over a specific range of time.
Within that there are specific time ranges that are marked as Within that, there are specific time ranges that are marked as
available via a set of "AVAILABLE" calendar sub-components. Together available via a set of "AVAILABLE" calendar sub-components. Together
these can be used to specify available time that can repeat over set these can be used to specify available time that can repeat over set
periods of time, and which can vary over time. periods of time, and which can vary over time.
3.1. Vavailability Component An illustration of how "VAVAILABILITY" and "AVAILABLE" components
work is shown below.
Time-range
<=========================================================>
+-------------------------------------------------+
| VAVAILABILITY |
+-------------------------------------------------+
+------------+ +------------+
| AVAILABLE | | AVAILABLE |
+------------+ +------------+
<-> <-----> <-----------> Busy Time
The overall time-range is shown at the top. A "VAVAILABILITY"
component spans part of the range. The time-range covered by the
"VAVAILABILITY" component is considered to be busy, except for the
ranges covered by the "AVAILABLE" components within the
"VAVAILABILITY" component.
3.1. VAVAILABILITY Component
Component Name: VAVAILABILITY Component Name: VAVAILABILITY
Purpose: Provide a grouping of component properties that describe Purpose: Provide a grouping of component properties and sub-
the availability associated with a calendar user. components that describe the availability associated with a
calendar user.
Format Definition: A "VAVAILABILITY" calendar component is defined Format Definition: A "VAVAILABILITY" calendar component is defined
by the following notation: by the following notation:
availabilityc = "BEGIN" ":" "VAVAILABILITY" CRLF availabilityc = "BEGIN" ":" "VAVAILABILITY" CRLF
availabilityprop *availablec availabilityprop *availablec
"END" ":" "VAVAILABILITY" CRLF "END" ":" "VAVAILABILITY" CRLF
availabilityprop = *( availabilityprop = *(
; ;
; the following are REQUIRED, ; the following are REQUIRED,
; but MUST NOT occur more than once ; but MUST NOT occur more than once
; ;
dtstamp / uid dtstamp / uid
; ;
; the following are OPTIONAL, ; the following are OPTIONAL,
; but MUST NOT occur more than once ; but MUST NOT occur more than once
; ;
busytype / class / created / description / busytype / class / created / description /
dtstart / last-mod / organizer / priority / dtstart / last-mod / organizer /
seq / summary / url / priority /seq / summary / url /
; ;
; either 'dtend' or 'duration' MAY appear ; Either 'dtend' or 'duration' MAY appear
; once, but 'dtend' and 'duration' MUST ; in an 'availableprop', but 'dtend' and
; NOT occur in the same 'availabilityprop'. ; 'duration' MUST NOT occur in the same
; ; 'availabilityprop'.
dtend / duration / ; 'duration' MUST NOT be present if
; ; 'dtstart' is not present
; the following are OPTIONAL, ;
; and MAY occur more than once dtend / duration /
; ;
categories / comment / contact / ; the following are OPTIONAL,
x-prop / iana-prop ; and MAY occur more than once
; ;
) categories / comment / contact /
x-prop / iana-prop
;
)
availablec = "BEGIN" ":" "AVAILABLE" CRLF availablec = "BEGIN" ":" "AVAILABLE" CRLF
availableprop availableprop
"END" ":" "AVAILABLE" CRLF "END" ":" "AVAILABLE" CRLF
availableprop = *( availableprop = *(
; ;
; the following are REQUIRED, ; the following are REQUIRED,
; but MUST NOT occur more than once ; but MUST NOT occur more than once
; ;
dtstamp / dtstart / uid / dtstamp / dtstart / uid /
; ;
; either 'dtend' or 'duration' MAY appear ; Either 'dtend' or 'duration' MAY appear in
; once, but 'dtend' and 'duration' MUST NOT ; an 'availableprop', but 'dtend' and
; occur in the same 'availableprop'. ; 'duration' MUST NOT occur in the same
; 'duration' MUST NOT be present if 'dtstart' ; 'availableprop'.
; is not present ;
; dtend / duration /
dtend / duration / ;
; ; the following are OPTIONAL,
; the following are OPTIONAL, ; but MUST NOT occur more than once
; but MUST NOT occur more than once ;
; created / description / last-mod /
created / description / last-mod / recurid / rrule / summary /
recurid / rrule / summary / ;
; ; the following are OPTIONAL,
; the following are OPTIONAL, ; and MAY occur more than once
; and MAY occur more than once ;
; categories / comment / contact / exdate /
categories / comment / contact / exdate / rdate / x-prop / iana-prop
rdate / x-prop / iana-prop
) )
Description: A "VAVAILABILITY" component indicates a period of time Description: A "VAVAILABILITY" component indicates a period of time
within which availability information is provided. A within which availability information is provided. A
"VAVAILABILITY" component can specify a start time and an end time "VAVAILABILITY" component can specify a start time and an end time
or duration. If "DTSTART" is not present, then the start time is or duration. If "DTSTART" is not present, then the start time is
unbounded. If "DTEND" or "DURATION" are not present, then the end unbounded. If "DTEND" or "DURATION" are not present, then the end
time is unbounded. Within the specified time period, availability time is unbounded. Within the specified time period, availability
defaults to a free-busy type of "BUSY-UNAVAILABLE", except for any defaults to a free-busy type of "BUSY-UNAVAILABLE" (see
time periods corresponding to "AVAILABLE" sub-components. Section 3.2), except for any time periods corresponding to
"AVAILABLE" sub-components.
"AVAILABLE" sub-components are used to indicate periods of free "AVAILABLE" sub-components are used to indicate periods of free
time within the time range of the enclosing "VAVAILABILITY" time within the time range of the enclosing "VAVAILABILITY"
component. "AVAILABLE" sub-components MAY include recurrence component. "AVAILABLE" sub-components MAY include recurrence
properties to specify recurring periods of time, which may be properties to specify recurring periods of time, which can be
overridden using normal recurrence behavior (i.e., use of the overridden using normal iCalendar recurrence behavior (i.e., use
"RECURRENCE-ID" property). of the "RECURRENCE-ID" property).
If specified, the "DTSTART" and "DTEND" properties in If specified, the "DTSTART" and "DTEND" properties in
"VAVAILABILITY" components and "AVAILABLE" sub-components MUST be "VAVAILABILITY" components and "AVAILABLE" sub-components MUST be
"DATE-TIME" values specified as either date with UTC time or date "DATE-TIME" values specified as either date with UTC time or date
with local time and a time zone reference. with local time and a time zone reference.
If any property with a "DATE-TIME" value is present in a The iCalendar object containing the "VAVAILABILITY" component MUST
"VAVAILABILITY" component or any of its "AVAILABLE" sub- contain appropriate "VTIMEZONE" components corresponding to each
components, and that property includes a "TZID" parameter, then unique "TZID" parameter value used in any DATE-TIME properties in
the iCalendar object containing the "VAVAILABILITY" component MUST all components.
contain "VTIMEZONE" components corresponding to each unique "TZID"
parameter value.
When used to publish available time, the "ORGANIZER" property When used to publish available time, the "ORGANIZER" property
specifies the calendar user associated with the published specifies the calendar user associated with the published
available time. available time.
If the "PRIORITY" property is specified in "VAVAILABILITY" If the "PRIORITY" property is specified in "VAVAILABILITY"
components it is used to determine how that component is combined components, it is used to determine how that component is combined
with other "VAVAILABILITY" components. See Section 4 with other "VAVAILABILITY" components. See Section 4.
Other calendar properties MAY be specified in "VAVAILABILITY" or Other calendar properties MAY be specified in "VAVAILABILITY" or
"AVAILABLE" components and are considered attributes of the marked "AVAILABLE" components and are considered attributes of the marked
block of time. Their usage is application specific. For example, block of time. Their usage is application specific. For example,
the "LOCATION" property may be used to indicate that a person is the "LOCATION" property might be used to indicate that a person is
available in one location for part of the week and another available in one location for part of the week and a different
location for another part. location for another part of the week.
Example: The following is an example of a "VAVAILABILITY" calendar Example: The following is an example of a "VAVAILABILITY" calendar
component used to represent the availability of a user always component used to represent the availability of a user, always
available Monday through Friday, 9:00 AM to 5:00 PM in the available Monday through Friday, 9:00 AM to 5:00 PM in the
America/Montreal time zone: America/Montreal time zone:
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-1@example.com UID:vavail-1@example.com
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:avail-1-A@example.com
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T170000 DTEND;TZID=America/Montreal:20111002T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
The following is an example of a "VAVAILABILITY" calendar The following is an example of a "VAVAILABILITY" calendar
component used to represent the availability of a user available component used to represent the availability of a user available
Monday through Thursday, 9:00 AM to 5:00 PM at the main office, Monday through Thursday, 9:00 AM to 5:00 PM at the main office,
and Friday 9:00 AM to 12:00 PM in the branch office in the and Friday 9:00 AM to 12:00 PM in the branch office in the
America/Montreal time zone between October 2nd and December 2nd America/Montreal time zone between October 2nd and December 2nd
2011: 2011:
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-1@example.com UID:vavail-1@example.com
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000 DTSTART;TZID=America/Montreal:20111002T000000
DTEND;TZID=America/Montreal:20111202T000000 DTEND;TZID=America/Montreal:20111202T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:avail-1-A@example.com
SUMMARY:Monday to Thursday from 9:00 to 17:00 SUMMARY:Monday to Thursday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T170000 DTEND;TZID=America/Montreal:20111002T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH
LOCATION:Main Office LOCATION:Main Office
END:AVAILABLE END:AVAILABLE
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-B@example.com UID:avail-1-B@example.com
SUMMARY:Friday from 9:00 to 12:00 SUMMARY:Friday from 9:00 to 12:00
DTSTART;TZID=America/Montreal:20111006T090000 DTSTART;TZID=America/Montreal:20111006T090000
DTEND;TZID=America/Montreal:20111006T120000 DTEND;TZID=America/Montreal:20111006T120000
RRULE:FREQ=WEEKLY RRULE:FREQ=WEEKLY
LOCATION:Branch Office LOCATION:Branch Office
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
The following is an example of three "VAVAILABILITY" calendar The following is an example of three "VAVAILABILITY" calendar
components used to represent the availability of a traveling components used to represent the availability of a traveling
worker: Monday through Friday, 9:00 AM to 5:00 PM each day. worker: Monday through Friday, 9:00 AM to 5:00 PM each day.
However, for three weeks the calendar user is working in Montreal, However, for three weeks the calendar user is working in Montreal,
then one week in Los Angeles, then back to Montreal. Note that then one week in Los Angeles, then back to Montreal. Note that
each overall period is covered by separate "VAVAILABILITY" each overall period is covered by separate "VAVAILABILITY"
components. The last of these has no DTEND so continues on "for components. The last of these has no DTEND so continues on "for
ever". This example shows one way "blocks" of available time can ever". This example shows one way "blocks" of available time can
be represented. See Section 4 for another approach using be represented. See Section 4 for another approach using
priority. priorities.
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-1@example.com UID:vavail-1@example.com
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000 DTSTART;TZID=America/Montreal:20111002T000000
DTEND;TZID=America/Montreal:20111023T030000 DTEND;TZID=America/Montreal:20111023T030000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:avail-1-A@example.com
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T170000 DTEND;TZID=America/Montreal:20111002T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Montreal LOCATION:Montreal
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-2@example.com UID:vavail-2@example.com
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Los_Angeles:20111023T000000 DTSTART;TZID=America/Los_Angeles:20111023T000000
DTEND;TZID=America/Los_Angeles:20111030T000000 DTEND;TZID=America/Los_Angeles:20111030T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-2-A@example.com UID:avail-2-A@example.com
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Los_Angeles:20111023T090000 DTSTART;TZID=America/Los_Angeles:20111023T090000
DTEND;TZID=America/Los_Angeles:20111023T170000 DTEND;TZID=America/Los_Angeles:20111023T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Los Angeles LOCATION:Los Angeles
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-3@example.com UID:vavail-3@example.com
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111030T030000 DTSTART;TZID=America/Montreal:20111030T030000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-3-A@example.com UID:avail-3-A@example.com
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111030T090000 DTSTART;TZID=America/Montreal:20111030T090000
DTEND;TZID=America/Montreal:20111030T170000 DTEND;TZID=America/Montreal:20111030T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Montreal LOCATION:Montreal
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
3.2. Busy Time Type 3.2. Busy Time Type
Property Name: BUSYTYPE Property Name: BUSYTYPE
Purpose: This property specifies the default busy time type. Purpose: This property specifies the default busy time type.
Value Type: TEXT Value Type: TEXT
Property Parameters: IANA and non-standard property parameters can Property Parameters: IANA and non-standard property parameters can
be specified on this property. be specified on this property.
Conformance: This property can be specified within "VAVAILABILITY" Conformance: This property can be specified within "VAVAILABILITY"
calendar components. calendar components.
Format Definition: This property is defined by the following Format Definition: This property is defined by the following
notation: notation:
busytype = "BUSYTYPE" busytypeparam ":" busytypevalue CRLF busytype = "BUSYTYPE" busytypeparam ":" busytypevalue CRLF
busytypeparam = *(";" other-param) busytypeparam = *(";" other-param)
busytypevalue = "BUSY" / "BUSY-UNAVAILABLE" / busytypevalue = "BUSY" / "BUSY-UNAVAILABLE" /
"BUSY-TENTATIVE" / iana-token / x-name "BUSY-TENTATIVE" / iana-token / x-name
; Default is "BUSY-UNAVAILABLE". ; Default is "BUSY-UNAVAILABLE".
Description: This property is used to specify the default busy time Description: This property is used to specify the default busy time
type. The values correspond to those used by the "FBTYPE" type. The values correspond to those used by the "FBTYPE"
parameter used on a "FREEBUSY" property, with the exception that parameter used on a "FREEBUSY" property, with the exception that
the "FREE" value is not used in this property. If not specified the "FREE" value is not used in this property. If not specified
on a component that allows this property, the default is "BUSY- on a component that allows this property, the default is "BUSY-
UNAVAILABLE". UNAVAILABLE".
Example: The following is an example of this property: Example: The following is an example of this property:
BUSYTYPE:BUSY BUSYTYPE:BUSY
4. Combining Vavailability components 4. Combining VAVAILABILITY components
The Vavailability component allows a calendar user to describe their The "VAVAILABILITY" component allows a calendar user to describe
availability over extended periods of time through the use of their availability over extended periods of time through the use of
recurrence patterns. This availability may be relatively constant recurrence patterns. This availability might be relatively constant
from year to year. from year to year.
However, there is usually some degree of irregularity, as people take However, there is usually some degree of irregularity, as people take
vacations or perhaps spend a few weeks at a different office. For vacations or perhaps spend a few weeks at a different office. For
that period of time there can be a need to redefine their that period of time there is a need to redefine their availability.
availability.
Rather than modify their existing vavailability, the "PRIORITY" Rather than modify their existing availability, the "PRIORITY"
property allows new vavailability components to be provided which property allows new "VAVAILABILITY" components to override others of
override others of lower ordinal priority. Note that iCalendar lower ordinal priority. Note that iCalendar [RFC5545] defines the
[RFC5545] defines the "PRIORITY" property such that a value of 0 is "PRIORITY" property such that a value of 0 is undefined, 1 is the
undefined, 1 is the highest priority and 9 is the lowest. highest priority and 9 is the lowest.
When combining vavailability components, an absence of a "PRIORITY" When combining "VAVAILABILITY" components, an absence of a "PRIORITY"
property or a value of 0 implies the lowest level of priority. If property or a value of 0 implies the lowest level of priority. When
two or more vavailability components have the same PRIORITY value, two or more VAVAILABILITY components overlap, and they have the same
then their AVAILABILITY components which fall within the date range PRIORITY value, the overlapping busy time type is determined by the
of interest are combined. It is up to the creator of such components following order: BUSY > BUSY-UNAVAILABLE > BUSY-TENTATIVE. i.e., if
to ensure that combining them produces a consistent and expected one component has a BUSYTYPE set to BUSY, and the another has
result. BUSYTYPE set to BUSY-UNAVAILABLE, then the effective busy time type
over the time range that they overlap would be BUSY. It is up to the
creator of such components to ensure that combining them produces a
consistent and expected result.
To calculate the available time, order the intersecting To calculate the available time, order the intersecting
"VAVAILABILITY" components by priority, those with no "PRIORITY" or a "VAVAILABILITY" components by priority (i.e., lowest to highest
priority value of 0 first, then in decreasing order of priority that "PRIORITY" values are 0, 9, 8, 7, 6, 5, 4, 3, 2, 1).
is, an increasing "PRIORITY" value.
Step through the resulting list of "VAVAILABILITY" components. For Step through the resulting list of "VAVAILABILITY" components. For
each, the time range covered by the "VAVAILABILITY" component is set each, the time range covered by the "VAVAILABILITY" component is set
to busy and then portions of it defined by the "AVAILABLE" components to busy and then portions of it defined by the "AVAILABLE" components
in the "VAVAILABILITY" component are set to free. in the "VAVAILABILITY" component are set to free.
Note that, if any VAVAILABILITY component completely covers the date Note that, if any "VAVAILABILITY" component completely covers the
range of interest, then any lower priority VAVAILABILITY components date range of interest, then any lower priority "VAVAILABILITY"
may be ignored. components can be ignored.
5. Calculating Free-Busy Time 5. Calculating Free-Busy Time
This section describes how free-busy time information for a calendar This section describes how free-busy time information for a calendar
user is calculated in the presence of "VAVAILABILITY" calendar user is calculated in the presence of "VAVAILABILITY" calendar
components. components.
An iCalendar "VFREEBUSY" component is used to convey "rolled-up" An iCalendar "VFREEBUSY" component is used to convey "rolled-up"
free-busy time information for a calendar user. This can be free-busy time information for a calendar user. This can be
generated as the result of an iTIP free-busy [RFC5546] request or generated as the result of an iTIP free-busy [RFC5546] request or
through some other mechanism (e.g., a CalDAV calendar-access through some other mechanism (e.g., a CalDAV calendar-access
CALDAV:free-busy-query REPORT). CALDAV:free-busy-query REPORT).
When one or more "VAVAILABILITY" components are present and intersect When one or more "VAVAILABILITY" components are present and intersect
the time-range for the free-busy request, first available time is the time-range for the free-busy request, first available time is
calculated, as outlined in Section 4. Once that is done, regular calculated, as outlined in Section 4. Once that is done, regular
"VEVENT" and "VFREEBUSY" components can be "overlaid" in the usual "VEVENT" and "VFREEBUSY" components can be "overlaid" in the usual
way to block out additional time. way to block out time.
An example procedure for this is as follows: An example procedure for this is as follows:
1. Initially mark the entire period of the free-busy request as 1. Initially mark the entire period of the free-busy request as
free. free.
2. For each "VAVAILABILITY" component ordered by PRIORITY: 2. For each "VAVAILABILITY" component ordered by PRIORITY:
1. Determine if the "VAVAILABILITY" intersects the time-range of 1. Determine if the "VAVAILABILITY" intersects the time-range of
the free-busy request. If not ignore it. the free-busy request. If not ignore it.
2. Determine if the "VAVAILABILITY" is completely overridden by 2. Determine if the "VAVAILABILITY" is completely overridden by
a higher priority component. If so ignore it. a higher priority component. If so ignore it.
3. For the time period covered by the "VAVAILABILITY" component, 3. For the time period covered by the "VAVAILABILITY" component,
mark time in the free-busy request result set as busy, using mark time in the free-busy request result set as busy, using
the busy time type derived from the "BUSYTYPE" property in the busy time type derived from the "BUSYTYPE" property in
the "VAVAILABILITY" component. the "VAVAILABILITY" component.
3. For each remaining "VAVAILABILITY" component in the same order: 3. For each remaining "VAVAILABILITY" component in order:
1. For each "AVAILABLE" component in the "VAVAILABILITY" 1. For each "AVAILABLE" component in the "VAVAILABILITY"
component: component:
1. Expand all recurring instances, taking into account 1. Expand all recurring instances, taking into account
overridden instances, ignoring instances or parts of overridden instances, ignoring instances or parts of
instances that fall outside of the free-busy request instances that fall outside of the free-busy request
time-range or the time period specified by the time-range or the time period specified by the
"VAVAILABILITY" component. "VAVAILABILITY" component.
skipping to change at page 13, line 19 skipping to change at page 13, line 19
| B | Represents "BUSY" time in that slot. | | B | Represents "BUSY" time in that slot. |
| U | Represents "BUSY-UNAVAILABLE" time in that slot. | | U | Represents "BUSY-UNAVAILABLE" time in that slot. |
| T | Represents "BUSY-TENTATIVE" time in that slot. | | T | Represents "BUSY-TENTATIVE" time in that slot. |
+-----------+--------------------------------------------------+ +-----------+--------------------------------------------------+
5.1.1. Simple Example 5.1.1. Simple Example
A free-busy request for Monday, 6th November 2011, midnight to A free-busy request for Monday, 6th November 2011, midnight to
midnight in the America/Montreal timezone. midnight in the America/Montreal timezone.
The user's calendar is as shown in Appendix A . This includes one The user's calendar is as shown in Appendix A. This includes one
"VAVAILABILITY" component giving available time within the requested "VAVAILABILITY" component giving available time within the requested
time-range of 8:00 AM to 6:00 PM, together with one "VEVENT" time-range of 8:00 AM to 6:00 PM, together with one "VEVENT"
component representing a two hour meeting starting at 12:00 PM. component representing a two hour meeting starting at 12:00 PM.
+------+----+----+----+----+----+----+----+----+----+----+----+----+ +------+----+----+----+----+----+----+----+----+----+----+----+----+
| Step | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | | Step | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 |
+------+----+----+----+----+----+----+----+----+----+----+----+----+ +------+----+----+----+----+----+----+----+----+----+----+----+----+
| 1. | F | F | F | F | F | F | F | F | F | F | F | F | | 1. | F | F | F | F | F | F | F | F | F | F | F | F |
| 2. | U | U | U | U | U | U | U | U | U | U | U | U | | 2. | U | U | U | U | U | U | U | U | U | U | U | U |
| 3. | U | U | U | U | F | F | F | F | F | U | U | U | | 3. | U | U | U | U | F | F | F | F | F | U | U | U |
| 4. | U | U | U | U | F | F | B | F | F | U | U | U | | 4. | U | U | U | U | F | F | B | F | F | U | U | U |
+------+----+----+----+----+----+----+----+----+----+----+----+----+ +------+----+----+----+----+----+----+----+----+----+----+----+----+
5.1.2. Further Example 5.1.2. Further Example
The following is another way to represent the availability of the The following is another way to represent the availability of the
traveling worker shown above. Here we represent their base traveling worker shown above. Here we represent their base
availability of Monday through Friday, 9:00 AM to 5:00 PM each day availability of Monday through Friday, 9:00 AM to 5:00 PM each day
with a "VAVAILABILITY" with defaulted PRIORITY. For the three weeks with a "VAVAILABILITY" with default "PRIORITY" (there is no "DTEND"
the calendar user is working in Montreal we represent it with an property so that this availability is unbounded). For the three
overriding "VAVAILABILITY" component with priority 1. weeks the calendar user is working in Los Angeles, we represent their
availability with a "VAVAILABILITY" component with priority 1, which
overrides the base availability.
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-1@example.com UID:vavail-1@example.com
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000 DTSTART;TZID=America/Montreal:20111002T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:avail-1-A@example.com
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T170000 DTEND;TZID=America/Montreal:20111002T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Montreal LOCATION:Montreal
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-2@example.com UID:vavail-2@example.com
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Los_Angeles:20111023T000000 DTSTART;TZID=America/Los_Angeles:20111023T000000
DTEND;TZID=America/Los_Angeles:20111030T000000 DTEND;TZID=America/Los_Angeles:20111030T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-2-A@example.com UID:avail-2-A@example.com
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Los_Angeles:20111023T090000 DTSTART;TZID=America/Los_Angeles:20111023T090000
DTEND;TZID=America/Los_Angeles:20111023T170000 DTEND;TZID=America/Los_Angeles:20111023T170000
PRIORITY:1 PRIORITY:1
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Los Angeles LOCATION:Los Angeles
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
6. CalDAV Extensions 6. Use with iTIP
6.1. CalDAV Requirements Overview This specification does not define how "VAVAILABILITY" components are
used in scheduling messages sent using the iTIP [RFC5546] protocol.
It is expected that future specifications will define how iTIP
scheduling can make use of "VAVAILABILITY" components.
7. CalDAV Extensions
7.1. CalDAV Requirements Overview
This section lists what functionality is required of a CalDAV server This section lists what functionality is required of a CalDAV server
which supports this extension. A server: which supports "VAVAILBILITY" components in stored calendar data. A
server:
o MUST support "VAVAILABILITY" components in a calendar collection o MUST advertise support for "VAVAILABILITY" components in
resource if the CALDAV calendar-access feature is supported, which CALDAV:supported-calendar-component-set properties on calendars
includes advertising it in CALDAV;supported-calendar-component-set which allow storing of such components;
properties on calendars;
o MUST support CALDAV:free-busy-query REPORTs that aggregate the o MUST support CALDAV:free-busy-query REPORTs that aggregate the
information in any "VAVAILABILITY" components in the calendar information in any "VAVAILABILITY" components in the calendar
collections targeted by the request; collections targeted by the request;
o MUST support "VAVAILABILITY" components stored in a o MUST support "VAVAILABILITY" components stored in a
CALDAV:calendar-availability WebDAV property on a CALDAV CALDAV:calendar-availability WebDAV property on a CALDAV
scheduling inbox collection if the CALDAV calendar-auto-schedule scheduling inbox collection, if the CALDAV calendar-auto-schedule
feature is supported; feature is supported;
o MUST support iTIP [RFC5546] free-busy requests that aggregate the o MUST support iTIP [RFC5546] free-busy requests that aggregate the
information in any "VAVAILABILITY" components in calendar information in any "VAVAILABILITY" components in calendar
collections that contribute to free-busy, or in any collections that contribute to free-busy, or in any
"VAVAILABILITY" components stored in the CALDAV:calendar- "VAVAILABILITY" components stored in the CALDAV:calendar-
availability in the CALDAV scheduling inbox collection of the availability property on the CALDAV scheduling inbox collection of
calendar user targeted by the iTIP free-busy request, if the the calendar user targeted by the iTIP free-busy request, if the
CalDAV calendar-auto-schedule feature is available. CalDAV calendar-auto-schedule feature is available.
6.2. New features in CalDAV "VAVAILABILITY" components are treated in a manner similar to
"VEVENT" and "VTODO" components, and MUST satisfy the other
requirements CalDAV imposes on calendar object resources (see
Section 4.1 of [RFC4791]).
6.2.1. Calendar Availability Support 7.2. New features in CalDAV
7.2.1. Calendar Availability Support
A server supporting the features described in this document MUST A server supporting the features described in this document MUST
include "calendar-availability" as a field in the DAV response header include "calendar-availability" as a field in the DAV response header
from an OPTIONS request on any resource that supports any calendar from an OPTIONS request. A value of "calendar-availability" in the
properties, reports, method, or privilege. A value of "calendar- DAV response header MUST indicate that the server supports all MUST
availability" in the DAV response header MUST indicate that the level requirements specified in this document.
server supports all MUST level requirements specified in this
document.
6.2.1.1. Example: Using OPTIONS for the Discovery of Calendar 7.2.1.1. Example: Using OPTIONS for the Discovery of Calendar
Availability Support Availability Support
>> Request << >> Request <<
OPTIONS /home/bernard/calendars/ HTTP/1.1 OPTIONS /home/bernard/calendars/ HTTP/1.1
Host: cal.example.com Host: cal.example.com
>> Response << >> Response <<
HTTP/1.1 200 OK HTTP/1.1 200 OK
Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE
Allow: PROPFIND, PROPPATCH, LOCK, UNLOCK, REPORT, ACL Allow: PROPFIND, PROPPATCH, LOCK, UNLOCK, REPORT, ACL
DAV: 1, 2, 3, access-control, calendar-access, DAV: 1, 2, 3, access-control, calendar-access,
calendar-availability calendar-availability
Date: Fri, 11 Nov 2005 09:32:12 GMT Date: Fri, 11 Nov 2005 09:32:12 GMT
Content-Length: 0 Content-Length: 0
In this example, the OPTIONS method returns the value "calendar- In this example, the OPTIONS method returns the value "calendar-
availability" in the DAV response header to indicate that the availability" in the DAV response header to indicate that the
collection "/home/bernard/calendars/" supports the new features collection "/home/bernard/calendars/" supports the new features
defined in this specification. defined in this specification.
6.2.2. CALDAV:free-busy-query REPORT 7.2.2. CALDAV:free-busy-query REPORT
A CALDAV:free-busy-query REPORT can be executed on a calendar A CALDAV:free-busy-query REPORT can be executed on a calendar
collection that contains iCalendar "VAVAILABILITY" components. When collection that contains iCalendar "VAVAILABILITY" components. When
that is done, the server MUST aggregate the information in any that occurs, the server MUST aggregate the information in any
"VAVAILABILITY" components when generating the free-busy response, as "VAVAILABILITY" components when generating the free-busy response, as
described in Section 5 . described in Section 5.
6.2.3. CALDAV:calendar-availability Property 7.2.3. CALDAV:calendar-availability Property
Name: calendar-availability Name: calendar-availability
Namespace: urn:ietf:params:xml:ns:caldav Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Defines a "VAVAILABILITY" component that will be used in Purpose: Defines a "VAVAILABILITY" component that will be used in
calculating free-busy time when an iTIP free-busy request is calculating free-busy time when an iTIP free-busy request is
targeted at the calendar user who owns the Inbox. targeted at the calendar user who owns the Inbox.
Conformance: This property MAY be protected and SHOULD NOT be Conformance: This property MAY be protected and SHOULD NOT be
returned by a PROPFIND DAV:allprop request. Support for this returned by a PROPFIND DAV:allprop request. Support for this
property is REQUIRED. The value of this property MUST be a valid property is REQUIRED. The value of this property MUST be a valid
iCalendar object containing "VAVAILABILITY" components and iCalendar object containing "VAVAILABILITY" components and
"VTIMEZONE" components (if required) only. "VTIMEZONE" components (if required) only.
Description: This property allows a user to specify their Description: This property allows a user to specify their
availability by including "VAVAILABILITY" components in the value availability by including an "VAVAILABILITY" component in the
of this property. If present, the server MUST use these value of this property. If present, the server MUST use this
"VAVAILABILITY" components when determining free-busy information "VAVAILABILITY" component when determining free-busy information
as part of an iTIP free-busy request being handled by the server. as part of an iTIP free-busy request being handled by the server.
Fot simplicity, only a single "VAVAILABILITY" component MUST be
present in the property. For more complex availability scenarios,
clients can store multiple "VAVAILABILITY" components in the
calendar user's calendar collections.
Definition: Definition:
<!ELEMENT calendar-availability (#PCDATA) > <!ELEMENT calendar-availability (#PCDATA) >
; Data value MUST be iCalendar object containing ; Data value MUST be iCalendar object containing
; "VAVAILABILITY" or "VTIMEZONE" components. ; "VAVAILABILITY" or "VTIMEZONE" components.
Example: Example:
<C:calendar-availability xmlns:D="DAV:" <C:calendar-availability xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:C="urn:ietf:params:xml:ns:caldav"
>BEGIN:VCALENDAR >BEGIN:VCALENDAR
CALSCALE:GREGORIAN CALSCALE:GREGORIAN
PRODID:-//example.com//iCalendar 2.0//EN PRODID:-//example.com//iCalendar 2.0//EN
VERSION:2.0 VERSION:2.0
BEGIN:VTIMEZONE BEGIN:VTIMEZONE
LAST-MODIFIED:20040110T032845Z LAST-MODIFIED:20040110T032845Z
TZID:America/Montreal TZID:America/Montreal
BEGIN:DAYLIGHT BEGIN:DAYLIGHT
DTSTART:20000404T020000 DTSTART:20000404T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
TZNAME:EDT TZNAME:EDT
TZOFFSETFROM:-0500 TZOFFSETFROM:-0500
TZOFFSETTO:-0400 TZOFFSETTO:-0400
END:DAYLIGHT END:DAYLIGHT
BEGIN:STANDARD BEGIN:STANDARD
DTSTART:20001026T020000 DTSTART:20001026T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZNAME:EST TZNAME:EST
TZOFFSETFROM:-0400 TZOFFSETFROM:-0400
TZOFFSETTO:-0500 TZOFFSETTO:-0500
END:STANDARD END:STANDARD
END:VTIMEZONE END:VTIMEZONE
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
UID:vavail-1@example.com UID:vavail-1@example.com
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000 DTSTART;TZID=America/Montreal:20111002T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:avail-1-A@example.com
SUMMARY:Monday to Friday from 9:00 to 18:00 SUMMARY:Monday to Friday from 9:00 to 18:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T180000 DTEND;TZID=America/Montreal:20111002T180000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
END:VCALENDAR END:VCALENDAR
</C:calendar-availability> </C:calendar-availability>
6.2.4. iTIP free-busy requests 7.2.4. iTIP free-busy requests
The [RFC6638] processing of an iTIP free-busy request targeted at the The [RFC6638] processing of an iTIP free-busy request targeted at the
owner of the CALDAV:schedule-inbox will include free-busy information owner of the CALDAV:schedule-inbox will include free-busy information
derived from "VAVAILABILITY" components in any calendar collection derived from "VAVAILABILITY" components in any calendar collection
targeted during the request, as described in Section 5. In addition, targeted during the request, as described in Section 5. In addition,
any "VAVAILABILITY" components specified in the CALDAV:calendar- any "VAVAILABILITY" component specified in the CALDAV:calendar-
availability property on the owner's Inbox, MUST be included in the availability property on the owner's Inbox, MUST be included in the
free-busy calculation. free-busy calculation.
7. Security Considerations 8. Security Considerations
Free-busy information generated from "VAVAILABILITY" components MUST Calculation of availability information, particularly with multiple
NOT include information other than busy or free time periods. In overlapping time-ranges, can be complex, and CalDAV servers MAY limit
particular, user specified property values such as "SUMMARY" and the complexity of such data stored by a client.
"DESCRIPTION" MUST NOT be copied into the free-busy result data.
An attacker able to "inject" availability information into a calendar
user's calendar data could ensure that the user never appears free
for meetings, or appears free at inappropriate times. Calendar
systems MUST ensure that availability information for a calendar user
can only be modified by authorized users.
Beyond this, this specification does not add any additional security Beyond this, this specification does not add any additional security
issues that are not already present in [RFC5545] and [RFC5546] . issues that are not already present in [RFC5545], [RFC5546],
[RFC4791] and [RFC6638].
8. IANA Considerations 9. Privacy Considerations
8.1. Component Registrations Normal free-busy information generated from "VAVAILABILITY"
components MUST NOT include information other than busy or free time
periods. In particular, user specified property values such as
"SUMMARY", "LOCATION" and "DESCRIPTION" MUST NOT be copied into the
free-busy result data.
Free-busy and availability information can be used by attackers to
infer the whereabouts or overall level of "activity" of the
corresponding calendar user. Any calendar system that allows a user
to expose their free-busy and availability information MUST limit
access to that information to only authorized users.
10. IANA Considerations
10.1. Component Registrations
This documents defines the following new iCalendar components to be This documents defines the following new iCalendar components to be
added to the registry defined in Section 8.2.2 of [RFC5545] : added to the registry defined in Section 8.2.2 of [RFC5545]:
+---------------+---------+-----------------------+ +---------------+---------+-----------------------+
| Component | Status | Reference | | Component | Status | Reference |
+---------------+---------+-----------------------+ +---------------+---------+-----------------------+
| VAVAILABILITY | Current | RFCXXXX, Section 3.1 | | VAVAILABILITY | Current | RFCXXXX, Section 3.1 |
| AVAILABLE | Current | RFCXXXX, Section 3.1 | | AVAILABLE | Current | RFCXXXX, Section 3.1 |
+---------------+---------+-----------------------+ +---------------+---------+-----------------------+
8.2. Property Registrations 10.2. Property Registrations
This documents defines the following new iCalendar properties to be This documents defines the following new iCalendar properties to be
added to the registry defined in Section 8.2.3 of [RFC5545] : added to the registry defined in Section 8.2.3 of [RFC5545]:
+----------+---------+-----------------------+ +----------+---------+-----------------------+
| Property | Status | Reference | | Property | Status | Reference |
+----------+---------+-----------------------+ +----------+---------+-----------------------+
| BUSYTYPE | Current | RFCXXXX, Section 3.2 | | BUSYTYPE | Current | RFCXXXX, Section 3.2 |
+----------+---------+-----------------------+ +----------+---------+-----------------------+
9. Acknowledgments 11. Acknowledgments
Thanks to the following for providing feedback: Toby Considine and Thanks to the following for providing feedback: Toby Considine
Dave Thewlis. Particular thanks go to Bernard Desruisseaux. This Bernard Desruisseaux, Evert Pot, Dave Thewlis. This specification
specification came about via discussions at the Calendaring and came about via discussions at the Calendaring and Scheduling
Scheduling Consortium. Consortium.
10. Normative References 12. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault, [RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault,
"Calendaring Extensions to WebDAV (CalDAV)", RFC 4791, "Calendaring Extensions to WebDAV (CalDAV)", RFC 4791, DOI
March 2007. 10.17487/RFC4791, March 2007,
<http://www.rfc-editor.org/info/rfc4791>.
[RFC5545] Desruisseaux, B., "Internet Calendaring and Scheduling [RFC5545] Desruisseaux, B., Ed., "Internet Calendaring and
Core Object Specification (iCalendar)", RFC 5545, Scheduling Core Object Specification (iCalendar)", RFC
September 2009. 5545, DOI 10.17487/RFC5545, September 2009,
<http://www.rfc-editor.org/info/rfc5545>.
[RFC5546] Daboo, C., "iCalendar Transport-Independent [RFC5546] Daboo, C., Ed., "iCalendar Transport-Independent
Interoperability Protocol (iTIP)", RFC 5546, December Interoperability Protocol (iTIP)", RFC 5546, DOI 10.17487/
2009. RFC5546, December 2009,
<http://www.rfc-editor.org/info/rfc5546>.
[RFC6638] Daboo, C. and B. Desruisseaux, "Scheduling Extensions to [RFC6638] Daboo, C. and B. Desruisseaux, "Scheduling Extensions to
CalDAV", RFC 6638, June 2012. CalDAV", RFC 6638, DOI 10.17487/RFC6638, June 2012,
<http://www.rfc-editor.org/info/rfc6638>.
Appendix A. Example Calendar #1 Appendix A. Example Calendar #1
iCalendar object iCalendar object
BEGIN:VCALENDAR BEGIN:VCALENDAR
CALSCALE:GREGORIAN CALSCALE:GREGORIAN
PRODID:-//example.com//iCalendar 2.0//EN PRODID:-//example.com//iCalendar 2.0//EN
VERSION:2.0 VERSION:2.0
BEGIN:VTIMEZONE BEGIN:VTIMEZONE
LAST-MODIFIED:20040110T032845Z LAST-MODIFIED:20040110T032845Z
TZID:America/Montreal TZID:America/Montreal
BEGIN:DAYLIGHT BEGIN:DAYLIGHT
DTSTART:20000404T020000 DTSTART:20000404T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
TZNAME:EDT TZNAME:EDT
TZOFFSETFROM:-0500 TZOFFSETFROM:-0500
TZOFFSETTO:-0400 TZOFFSETTO:-0400
END:DAYLIGHT END:DAYLIGHT
BEGIN:STANDARD BEGIN:STANDARD
DTSTART:20001026T020000 DTSTART:20001026T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZNAME:EST TZNAME:EST
TZOFFSETFROM:-0400 TZOFFSETFROM:-0400
TZOFFSETTO:-0500 TZOFFSETTO:-0500
END:STANDARD END:STANDARD
END:VTIMEZONE END:VTIMEZONE
BEGIN:VEVENT BEGIN:VEVENT
DTSTAMP:20111113T044111Z DTSTAMP:20111113T044111Z
DTSTART;TZID=America/Montreal:20111106T120000 DTSTART;TZID=America/Montreal:20111106T120000
DURATION:PT1H DURATION:PT1H
SUMMARY:Meeting SUMMARY:Meeting
UID:60A48841ECB90F3F215FE3D2@example.com UID:60A48841ECB90F3F215FE3D2@example.com
END:VEVENT END:VEVENT
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
UID:vavail-1@example.com UID:vavail-1@example.com
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000 DTSTART;TZID=America/Montreal:20111002T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:avail-1-A@example.com
SUMMARY:Monday to Friday from 9:00 to 18:00 SUMMARY:Monday to Friday from 9:00 to 18:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T180000 DTEND;TZID=America/Montreal:20111002T180000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
END:VCALENDAR END:VCALENDAR
Appendix B. Change History (To be removed by RFC Editor before Appendix B. Change History (To be removed by RFC Editor before
publication) publication)
Changes in -05: Changes in draft-ietf-calext-availability-01:
1. Minor editorial fixes.
2. ABNF syntax fixes.
3. Clarify BUSTYPE precedence when combining components with the
same PRIORITY values.
4. Added section explaining that iTIP use is not defined
5. Added Privacy Considerations and tweaked Security Considerations.
6. Added diagram to illustrate the overall concept.
7. Limit the calendar-availability property to a single
"VAVAILABILITY" component.
Changes in draft-ietf-calext-availability-00:
1. Re-publication as WG document.
Changes in draft-daboo-calendar-availability-05:
1. Small typos. 1. Small typos.
2. Fix explanation of priority. 2. Fix explanation of priority.
3. Change uid values to make legal and easier to follow. 3. Change uid values to make legal and easier to follow.
Changes in -04: Changes in draft-daboo-calendar-availability-04:
1. Small typos. 1. Small typos.
2. Add prioritized example. 2. Add prioritized example.
Changes in -03: Changes in draft-daboo-calendar-availability-03:
1. Switch authors. 1. Switch authors.
2. CalDAV scheduling is now rfc6638. 2. CalDAV scheduling is now rfc6638.
3. List priority as a vavailability property and define its use. 3. List priority as a vavailability property and define its use.
Changes in -02: Changes in draft-daboo-calendar-availability-02:
1. Updated to 5545/5546 references. 1. Updated to 5545/5546 references.
2. Fixed some examples. 2. Fixed some examples.
3. Added some more properties to the components 3. Added some more properties to the components
4. Fixed text that said dtstart was required in VAVAILABILITY 4. Fixed text that said dtstart was required in VAVAILABILITY
Changes in -01: Changes in draft-daboo-calendar-availability-01:
1. Allow property on Inbox for caldav-schedule. 1. Allow property on Inbox for caldav-schedule.
2. Clarify that DURATION can only be present in VAVAILABILITY if 2. Clarify that DURATION can only be present in VAVAILABILITY if
DTSTART is also present, and DTEND is not. DTSTART is also present, and DTEND is not.
3. Updated references. 3. Updated references.
4. Added templates. 4. Added templates.
 End of changes. 92 change blocks. 
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