Network Working Group C. Daboo
Internet-Draft Apple Inc.
Intended status: Standards Track B. Desruisseaux
Expires: December 21, 2009 Oracle
June 19, 2009
CalDAV Scheduling Extensions to WebDAV
draft-desruisseaux-caldav-sched-07
Status of This Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. This document may contain material
from IETF Documents or IETF Contributions published or made publicly
available before November 10, 2008. The person(s) controlling the
copyright in some of this material may not have granted the IETF
Trust the right to allow modifications of such material outside the
IETF Standards Process. Without obtaining an adequate license from
the person(s) controlling the copyright in such materials, this
document may not be modified outside the IETF Standards Process, and
derivative works of it may not be created outside the IETF Standards
Process, except to format it for publication as an RFC or to
translate it into languages other than English.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on December 21, 2009.
Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved.
Daboo & Desruisseaux Expires December 21, 2009 [Page 1]
Internet-Draft CalDAV Scheduling Extensions June 2009
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
Daboo & Desruisseaux Expires December 21, 2009 [Page 2]
Internet-Draft CalDAV Scheduling Extensions June 2009
Abstract
This document defines extensions to the CalDAV "calendar-access"
feature to specify a standard way of performing scheduling
transactions with iCalendar-based calendar components. This document
defines the "calendar-auto-schedule" feature of CalDAV.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7
1.2. Approach . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.3. Limitations . . . . . . . . . . . . . . . . . . . . . . . 8
1.4. Notational Conventions . . . . . . . . . . . . . . . . . . 9
1.5. XML Namespaces and Processing . . . . . . . . . . . . . . 9
2. Scheduling Process . . . . . . . . . . . . . . . . . . . . . . 11
3. Scheduling Support . . . . . . . . . . . . . . . . . . . . . . 12
4. Scheduling Collections . . . . . . . . . . . . . . . . . . . . 13
4.1. Scheduling Outbox Collection . . . . . . . . . . . . . . . 13
4.2. Scheduling Inbox Collection . . . . . . . . . . . . . . . 14
4.3. Calendaring Reports Extensions . . . . . . . . . . . . . . 16
5. Scheduling Transactions . . . . . . . . . . . . . . . . . . . 17
5.1. Identifying Scheduling Object Resources . . . . . . . . . 17
5.2. Handling Scheduling Object Resources . . . . . . . . . . . 17
5.2.1. Organizer Scheduling Object Resources . . . . . . . . 17
5.2.1.1. Create . . . . . . . . . . . . . . . . . . . . . . 18
5.2.1.2. Modify . . . . . . . . . . . . . . . . . . . . . . 19
5.2.1.3. Remove . . . . . . . . . . . . . . . . . . . . . . 20
5.2.2. Attendee Scheduling Object Resources . . . . . . . . . 21
5.2.2.1. Allowed Attendee Changes . . . . . . . . . . . . . 21
5.2.2.2. Create . . . . . . . . . . . . . . . . . . . . . . 22
5.2.2.3. Modify . . . . . . . . . . . . . . . . . . . . . . 22
5.2.2.4. Remove . . . . . . . . . . . . . . . . . . . . . . 22
5.2.3. HTTP Methods . . . . . . . . . . . . . . . . . . . . . 23
5.2.3.1. PUT . . . . . . . . . . . . . . . . . . . . . . . 23
5.2.3.2. COPY . . . . . . . . . . . . . . . . . . . . . . . 24
5.2.3.3. MOVE . . . . . . . . . . . . . . . . . . . . . . . 24
5.2.3.4. DELETE . . . . . . . . . . . . . . . . . . . . . . 25
5.2.4. Additional Method Preconditions . . . . . . . . . . . 25
5.2.4.1. CALDAV:unique-scheduling-object-resource
Precondition . . . . . . . . . . . . . . . . . . . 25
5.2.4.2. CALDAV:same-organizer-in-all-components
Precondition . . . . . . . . . . . . . . . . . . . 25
5.2.4.3. CALDAV:allowed-organizer-scheduling-object-chan
Precondition . . . . . . . . . . . . . . . . . . . 26
5.2.4.4. CALDAV:allowed-attendee-scheduling-object-chang
Precondition . . . . . . . . . . . . . . . . . . . 27
5.2.5. DTSTAMP and SEQUENCE Properties . . . . . . . . . . . 27
Daboo & Desruisseaux Expires December 21, 2009 [Page 3]
Internet-Draft CalDAV Scheduling Extensions June 2009
5.2.6. Limit Recurrence Instances Sent to Attendees . . . . . 27
5.2.7. Forcing the Server to Send a Scheduling Message . . . 28
6. Processing Incoming Scheduling Messages . . . . . . . . . . . 29
6.1. Processing Attendee Replies . . . . . . . . . . . . . . . 29
6.2. Processing Organizer Requests, Additions, and
Cancellations . . . . . . . . . . . . . . . . . . . . . . 30
6.3. Default Calendar Collection . . . . . . . . . . . . . . . 30
6.3.1. Additional Method Preconditions . . . . . . . . . . . 31
6.3.1.1. CALDAV:default-calendar-delete-allowed
Precondition . . . . . . . . . . . . . . . . . . . 31
6.3.1.2. CALDAV:valid-schedule-default-calendar-URL
Precondition . . . . . . . . . . . . . . . . . . . 31
6.4. Scheduling Messages as Notifications . . . . . . . . . . . 32
7. Request for Busy Time Information . . . . . . . . . . . . . . 33
7.1. Status Codes . . . . . . . . . . . . . . . . . . . . . . . 33
7.2. Additional Method Preconditions . . . . . . . . . . . . . 33
7.2.1. DAV:need-privileges Precondition . . . . . . . . . . . 33
7.2.2. CALDAV:supported-collection Precondition . . . . . . . 34
7.2.3. CALDAV:supported-calendar-data Precondition . . . . . 35
7.2.4. CALDAV:valid-calendar-data Precondition . . . . . . . 35
7.2.5. CALDAV:valid-scheduling-message Precondition . . . . . 36
7.2.6. CALDAV:organizer-allowed Precondition . . . . . . . . 36
7.2.7. CALDAV:max-resource-size Precondition . . . . . . . . 37
7.3. Response to a POST request . . . . . . . . . . . . . . . . 37
8. Conditional Requests on Scheduling Object Resources . . . . . 38
8.1. PUT . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
8.2. DELETE . . . . . . . . . . . . . . . . . . . . . . . . . . 40
8.3. COPY or MOVE . . . . . . . . . . . . . . . . . . . . . . . 41
9. Other Scheduling Considerations . . . . . . . . . . . . . . . 42
9.1. Attendee Participation Status . . . . . . . . . . . . . . 42
9.2. Schedule Status Values . . . . . . . . . . . . . . . . . . 43
9.3. Organizer is an Attendee . . . . . . . . . . . . . . . . . 45
10. Additional iCalendar Property Parameters . . . . . . . . . . . 46
10.1. Schedule Agent Parameter . . . . . . . . . . . . . . . . . 46
10.2. Schedule Force Send Parameter . . . . . . . . . . . . . . 47
10.3. Schedule Status Parameter . . . . . . . . . . . . . . . . 48
11. Additional Message Header Fields . . . . . . . . . . . . . . . 50
11.1. Schedule-Reply Request Header . . . . . . . . . . . . . . 50
11.2. Schedule-Tag Response Header . . . . . . . . . . . . . . . 50
11.3. If-Schedule-Tag-Match Request Header . . . . . . . . . . . 51
12. Additional WebDAV Properties . . . . . . . . . . . . . . . . . 52
12.1. CALDAV:schedule-calendar-transp Property . . . . . . . . . 52
12.2. CALDAV:schedule-default-calendar-URL Property . . . . . . 53
12.3. CALDAV:schedule-tag Property . . . . . . . . . . . . . . . 54
13. Scheduling Access Control . . . . . . . . . . . . . . . . . . 55
13.1. Scheduling Privileges . . . . . . . . . . . . . . . . . . 55
13.1.1. Privileges on Scheduling Inbox Collections . . . . . . 55
13.1.1.1. CALDAV:schedule-deliver Privilege . . . . . . . . 55
Daboo & Desruisseaux Expires December 21, 2009 [Page 4]
Internet-Draft CalDAV Scheduling Extensions June 2009
13.1.1.2. CALDAV:schedule-deliver-invite Privilege . . . . . 56
13.1.1.3. CALDAV:schedule-deliver-reply Privilege . . . . . 56
13.1.1.4. CALDAV:schedule-query-freebusy Privilege . . . . . 56
13.1.2. Privileges on Scheduling Outbox Collections . . . . . 56
13.1.2.1. CALDAV:schedule-send Privilege . . . . . . . . . . 56
13.1.2.2. CALDAV:schedule-send-invite Privilege . . . . . . 57
13.1.2.3. CALDAV:schedule-send-reply Privilege . . . . . . . 57
13.1.2.4. CALDAV:schedule-send-freebusy Privilege . . . . . 57
13.1.3. Aggregation of Scheduling Privileges . . . . . . . . . 57
13.2. Additional Principal Properties . . . . . . . . . . . . . 58
13.2.1. CALDAV:schedule-inbox-URL Property . . . . . . . . . . 58
13.2.2. CALDAV:schedule-outbox-URL Property . . . . . . . . . 59
13.2.3. CALDAV:calendar-user-address-set Property . . . . . . 59
13.2.4. CALDAV:calendar-user-type Property . . . . . . . . . . 60
14. XML Element Definitions . . . . . . . . . . . . . . . . . . . 62
14.1. CALDAV:schedule-response XML Element . . . . . . . . . . . 62
14.2. CALDAV:response XML Element . . . . . . . . . . . . . . . 62
14.3. CALDAV:recipient XML Element . . . . . . . . . . . . . . . 62
14.4. CALDAV:request-status XML Element . . . . . . . . . . . . 63
15. Security Considerations . . . . . . . . . . . . . . . . . . . 64
15.1. Verifying Scheduling Transactions . . . . . . . . . . . . 64
15.2. Verifying Busy Time Information Requests . . . . . . . . . 64
15.3. Privacy Issues . . . . . . . . . . . . . . . . . . . . . . 65
16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 66
16.1. Message Header Field Registrations . . . . . . . . . . . . 66
16.1.1. Schedule-Reply . . . . . . . . . . . . . . . . . . . . 66
16.1.2. Schedule-Tag . . . . . . . . . . . . . . . . . . . . . 66
16.1.3. If-Schedule-Tag-Match . . . . . . . . . . . . . . . . 66
16.2. iCalendar Property Parameter Registrations . . . . . . . . 67
16.3. Additional iCalendar Elements Registries . . . . . . . . . 67
16.3.1. Schedule Agent Values Registry . . . . . . . . . . . . 67
16.3.2. Schedule Force Send Values Registry . . . . . . . . . 67
17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 69
18. References . . . . . . . . . . . . . . . . . . . . . . . . . . 70
18.1. Normative References . . . . . . . . . . . . . . . . . . . 70
18.2. Informative References . . . . . . . . . . . . . . . . . . 71
Appendix A. Scheduling Privileges Summary . . . . . . . . . . . . 72
A.1. Scheduling Inbox Privileges . . . . . . . . . . . . . . . 72
A.2. Scheduling Outbox Privileges . . . . . . . . . . . . . . . 72
Appendix B. Example Scheduling Transactions . . . . . . . . . . . 74
B.1. Example: Organizer Inviting Multiple Attendees . . . . . . 74
B.2. Example: Attendee Receiving an Invitation . . . . . . . . 76
B.3. Example: Attendee Replying to an Invitation . . . . . . . 78
B.4. Example: Organizer Receiving a Reply to an Invitation . . 80
B.5. Example: Organizer Requesting Busy Time Information . . . 82
B.6. Example: User Attempting to Invite Attendee on behalf
of Organizer . . . . . . . . . . . . . . . . . . . . . . . 84
B.7. Example: Attendee Declining an Instance of a Recurring
Daboo & Desruisseaux Expires December 21, 2009 [Page 5]
Internet-Draft CalDAV Scheduling Extensions June 2009
Event . . . . . . . . . . . . . . . . . . . . . . . . . . 85
B.8. Example: Attendee Removing an Instance of a Recurring
Event . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Appendix C. Changes (to be removed by RFC Editor prior to
publication) . . . . . . . . . . . . . . . . . . . . 92
C.1. Changes in -07 . . . . . . . . . . . . . . . . . . . . . . 92
C.2. Changes in -06 . . . . . . . . . . . . . . . . . . . . . . 92
C.3. Changes in -05 . . . . . . . . . . . . . . . . . . . . . . 93
Daboo & Desruisseaux Expires December 21, 2009 [Page 6]
Internet-Draft CalDAV Scheduling Extensions June 2009
1. Introduction
This document specifies extensions to the CalDAV "calendar-access"
[RFC4791] feature to enable scheduling of iCalendar-based
[I-D.ietf-calsify-rfc2445bis] calendar components between Calendar
Users. This extension leverages the scheduling methods defined in
the iCalendar Transport-independent Interoperability Protocol (iTIP)
[I-D.ietf-calsify-2446bis] to permit Calendar Users to perform
scheduling transactions such as schedule, reschedule, respond to
scheduling request or cancel scheduled calendar components, as well
as search for busy time information.
Discussion of this Internet-Draft is taking place on the mailing list
<https://www.ietf.org/mailman/listinfo/caldav>.
1.1. Terminology
This specification uses much of the same terminology as iCalendar
[I-D.ietf-calsify-rfc2445bis], iTIP [I-D.ietf-calsify-2446bis],
WebDAV [RFC4918], and CalDAV [RFC4791]. The following definitions
are provided to aid the reader in understanding this specification.
Calendar User (CU): An entity (often a human) that accesses calendar
information [RFC3283].
Calendar User Agent (CUA): Software with which the calendar user
communicates with a calendar service or local calendar store to
access calendar information [RFC3283].
Calendar collection: A resource that acts as a container of
references to child calendar object resources [RFC4791].
Calendar object resource: A resource representing a calendar object
(event, to-do, journal entry, or other calendar components)
[RFC4791].
Scheduling object resource: A calendar object resource contained in
a calendar collection for which the server will take care of
sending scheduling messages on behalf of the owner of the calendar
collection.
Organizer scheduling object resource: A scheduling object resource
owned by an Organizer.
Attendee scheduling object resource: A scheduling object resource
owned by an Attendee.
Daboo & Desruisseaux Expires December 21, 2009 [Page 7]
Internet-Draft CalDAV Scheduling Extensions June 2009
Automatic scheduling transaction: Add, change or remove operations
on a scheduling object resource for which the server will deliver
scheduling messages to other Calendar Users.
Scheduling message: A calendar object resource that describes a
scheduling transaction such as schedule, reschedule, reply, or
cancel.
Scheduling Outbox collection: A resource at which busy time
information requests are targeted.
Scheduling Inbox collection: A collection in which incoming
scheduling messages are delivered.
1.2. Approach
iTIP [I-D.ietf-calsify-2446bis] outlines a model where Calendar Users
exchange scheduling messages with one another. Often times, Calendar
User Agents are made responsible for generating and sending
scheduling messages as well as processing incoming scheduling
messages. This approach yields a number of problems, including:
o For most updates to a scheduled calendar component, Calendar User
Agents need to address a separate scheduling messages to the
Organizer or the Attendees.
o The handling of incoming scheduling messages and the updates to
calendars impacted by those messages only occurs when Calendar
User Agents are active.
o Due to the update latency, it is possible for calendars of
different Calendar Users to reflect different, inaccurate states.
This specification uses an alternative approach where the server is
made responsible for sending scheduling messages and processing
incoming scheduling messages. This approach frees the Calendar User
Agents from the submission and processing of scheduling messages and
ensures better consistency of calendar data across users' calendars.
The operation of creating, modifying or deleting a scheduled calendar
component in a calendar is enough to trigger the server to deliver
the necessary scheduling messages to the appropriate Calendar Users.
1.3. Limitations
While the scheduling features described in this specification are
based on iTIP [I-D.ietf-calsify-2446bis], some of its more complex
features have deliberately been left out in order to keep this
specification simple. In particular, the following iTIP
Daboo & Desruisseaux Expires December 21, 2009 [Page 8]
Internet-Draft CalDAV Scheduling Extensions June 2009
[I-D.ietf-calsify-2446bis] features are not covered: publishing,
countering, delegating, refreshing and forwarding calendar
components, as well as replacing the Organizer of a calendar
component.
The goal of this specification is to provide the essential scheduling
features needed. It is expected that future extensions will be
developed to address the more complex features.
1.4. Notational Conventions
The Augmented BNF (ABNF) syntax used by this document to specify the
format definition of new iCalendar elements is defined in [RFC5234].
The Augmented BNF (ABNF) syntax used by this document to specify the
format definition of new message header fields to be used with the
HTTP/1.1 protocol is described in Section 2.1 of [RFC2616]. Since
this Augmented BNF uses the basic production rules provided in
Section 2.2 of [RFC2616], these rules apply to this document as well.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
When XML element types in the namespaces "DAV:" and
"urn:ietf:params:xml:ns:caldav" are referenced in this document
outside of the context of an XML fragment, the string "DAV:" and
"CALDAV:" will be prefixed to the element types respectively.
1.5. XML Namespaces and Processing
Definitions of XML elements in this document use XML element type
declarations (as found in XML Document Type Declarations), described
in Section 3.2 of [W3C.REC-xml-20081126].
The XML elements specified in this document are defined in the
"urn:ietf:params:xml:ns:caldav" XML namespace registered by CalDAV
[RFC4791].
The XML declarations used in this document do not include namespace
information. Thus, implementers must not use these declarations as
the only way to create valid CalDAV properties or to validate CalDAV
XML element type. Some of the declarations refer to XML elements
defined by WebDAV [RFC4918] which use the "DAV:" namespace. Wherever
such XML elements appear, they are explicitly prefixed with "DAV:" to
avoid confusion. Additionally, some of the elements used here are
defined in CalDAV "calendar-access" [RFC4791].
Daboo & Desruisseaux Expires December 21, 2009 [Page 9]
Internet-Draft CalDAV Scheduling Extensions June 2009
Also note that some CalDAV XML element names are identical to WebDAV
XML element names, though their namespace differs. Care must be
taken not to confuse the two sets of names.
Processing of XML by CalDAV clients and servers MUST follow the rules
described in Section 17 of [RFC4918].
Daboo & Desruisseaux Expires December 21, 2009 [Page 10]
Internet-Draft CalDAV Scheduling Extensions June 2009
2. Scheduling Process
The process of scheduling an event between different parties often
involves a series of steps with different actors playing particular
roles during the whole process. Typically there is an event
"Organizer" whose role is to setup an event between one or more
"Attendees", and this is done by sending out invitations and handling
responses from each Attendee.
This process can typically be broken down into two phases.
In the first phase, the Organizer will query the busy time
information of each Attendee to determine the most appropriate time
for the event. This request is sometimes called a freebusy lookup.
In the second phase, the Organizer sends out invitations to each
Attendee using the time previously determined from the freebusy
lookup. There then follows exchanges between Organizer and Attendees
regarding the invitation. Some Attendees may choose to attend at the
time proposed by the Organizer, others may decline to attend. The
Organizer needs to process each of the replies from the Attendees and
take appropriate action to confirm the event, reschedule it or
perhaps cancel it.
The user expectation as to how a calendaring and scheduling system
should respond in each of these two phases is somewhat different. In
the case of a freebusy lookup, users expect to get back results
immediately so that they can then move on to the invitation phase as
quickly as possible. In the case of invitations, it is expected that
each Attendee will reply with their participation status in their own
time, so delays in receiving replies are anticipated. Thus
calendaring and scheduling systems should treat these two operational
phases in different ways to accommodate the user expectations, and
this specification does that.
While the scenario described above only covers the case of scheduling
events between Calendar Users, and requesting busy time information,
this specification also provides support for the scheduling of to-dos
between Calendar Users. For the majority of the following
discussion, scheduling of events and freebusy lookups will be
discussed, as these are the more common operations.
Daboo & Desruisseaux Expires December 21, 2009 [Page 11]
Internet-Draft CalDAV Scheduling Extensions June 2009
3. Scheduling Support
A server that supports the features described in this document MUST
include "calendar-auto-schedule" as a field in the DAV response
header from an OPTIONS request on any resource that supports any
scheduling actions, properties, privileges or methods.
To advertise support for the CalDAV "calendar-auto-schedule" feature
a server is REQUIRED to support and advertise support for the CalDAV
"calendar-access" [RFC4791] feature.
>> Request <<
OPTIONS /home/cyrus/calendars/inbox/ HTTP/1.1
Host: cal.example.com
>> Response <<
HTTP/1.1 204 No Content
Date: Thu, 31 Mar 2005 09:00:00 GMT
Allow: OPTIONS, GET, HEAD, DELETE, TRACE, PROPFIND
Allow: PROPPATCH, LOCK, UNLOCK, REPORT, ACL
DAV: 1, 2, 3, access-control
DAV: calendar-access, calendar-auto-schedule
In this example, the OPTIONS response indicates that the server
supports the "calendar-access" and "calendar-auto-schedule" features
and that resource "/home/cyrus/calendars/inbox/" supports the
scheduling actions, properties, privileges and methods defined in
this specification.
Daboo & Desruisseaux Expires December 21, 2009 [Page 12]
Internet-Draft CalDAV Scheduling Extensions June 2009
4. Scheduling Collections
This specification introduces new collection resource types that are
used to manage scheduling object resources, scheduling privileges as
well as provide scheduling functionality.
4.1. Scheduling Outbox Collection
A scheduling Outbox collection is used as the target for busy time
information requests.
A scheduling Outbox collection MUST report the DAV:collection and
CALDAV:schedule-outbox XML elements in the value of the DAV:
resourcetype property. The element type declaration for CALDAV:
schedule-outbox is:
<!ELEMENT schedule-outbox EMPTY>
Example:
<D:resourcetype xmlns:D="DAV:">
<D:collection/>
<C:schedule-outbox xmlns:C="urn:ietf:params:xml:ns:caldav"/>
</D:resourcetype>
New WebDAV ACL [RFC3744] privileges can be set on the scheduling
Outbox collection to control who is allowed to send scheduling
messages on behalf of the Calendar User associated with the
scheduling Outbox collection. See Section 13.1 for more details.
A scheduling Outbox collection MUST NOT be a child (at any depth) of
a calendar collection resource.
The following WebDAV properties specified in CalDAV "calendar-access"
[RFC4791] MAY also be defined on scheduling Outbox collections:
CALDAV:supported-calendar-component-set - when present this
indicates the allowed calendar component types for scheduling
messages submitted to the scheduling Outbox collection with the
POST method.
CALDAV:supported-calendar-data - when present this indicates the
allowed media types for scheduling messages submitted to the
scheduling Outbox collection with the POST method.
CALDAV:max-resource-size - when present this indicates the maximum
size of a resource in octets that the server is willing to accept
for scheduling messages submitted to the scheduling Outbox
Daboo & Desruisseaux Expires December 21, 2009 [Page 13]
Internet-Draft CalDAV Scheduling Extensions June 2009
collection with the POST method.
CALDAV:min-date-time - when present this indicates the earliest
date and time (in UTC) that the server is willing to accept for
any DATE or DATE-TIME value in scheduling messages submitted to
the scheduling Outbox collection with the POST method.
CALDAV:max-date-time - when present this indicates the latest date
and time (in UTC) that the server is willing to accept for any
DATE or DATE-TIME value in scheduling messages submitted to the
scheduling Outbox collection with the POST method.
CALDAV:max-instances - when present this indicates the maximum
number of recurrence instances in scheduling messages submitted to
the scheduling Outbox collection with the POST method.
CALDAV:max-attendees-per-instance - when present this indicates
the maximum number of ATTENDEE properties in any instance of
scheduling messages submitted to the scheduling Outbox collection
with the POST method.
While there is currently no defined use for child resources in a
scheduling Outbox collection, a scheduling Outbox collection MAY
contain child resources.
4.2. Scheduling Inbox Collection
A scheduling Inbox collection contains copies of incoming scheduling
messages. These may be requests sent by an Organizer, or replies
sent by an Attendee in response to a request.
A scheduling Inbox collection MUST report the DAV:collection and
CALDAV:schedule-inbox XML elements in the value of the DAV:
resourcetype property. The element type declaration for CALDAV:
schedule-inbox is:
<!ELEMENT schedule-inbox EMPTY>
Example:
<D:resourcetype xmlns:D="DAV:">
<D:collection/>
<C:schedule-inbox xmlns:C="urn:ietf:params:xml:ns:caldav"/>
</D:resourcetype>
Scheduling Inbox collections MUST only contain calendar object
resources that obey the restrictions specified in iTIP
[I-D.ietf-calsify-2446bis]. Consequently, scheduling Inbox
Daboo & Desruisseaux Expires December 21, 2009 [Page 14]
Internet-Draft CalDAV Scheduling Extensions June 2009
collections MUST NOT contain any types of collection resources.
Restrictions defined in Section 4.1 of CalDAV "calendar-access"
[RFC4791] on calendar object resources contained in calendar
collections (e.g., "UID" uniqueness) don't apply to calendar object
resources contained in a scheduling Inbox collection. Multiple
calendar object resources contained in a scheduling Inbox collection
MAY have the same "UID" property value (i.e., multiple scheduling
messages for the same calendar component).
New WebDAV ACL [RFC3744] privileges can be set on the scheduling
Inbox collection to control who the Calendar User associated with the
scheduling Inbox collection will accept scheduling messages from.
See Section 13.1 for more details.
A scheduling Inbox collection MUST NOT be a child (at any depth) of a
calendar collection resource.
The following WebDAV properties specified in CalDAV "calendar-access"
[RFC4791] MAY also be defined on scheduling Inbox collections:
CALDAV:calendar-timezone - when present this contains a time zone
that the server can use when calendar date-time operations are
carried out, for example when a time-range CALDAV:calendar-query
REPORT is targeted at a scheduling Inbox collection.
CALDAV:supported-calendar-component-set - when present this
indicates the allowed calendar component types for scheduling
messages delivered to the scheduling Inbox collection.
CALDAV:supported-calendar-data - when present this indicates the
allowed media types for scheduling messages delivered to the
scheduling Inbox collection.
CALDAV:max-resource-size - when present this indicates the maximum
size of a resource in octets that the server is willing to accept
for scheduling messages delivered to the scheduling Inbox
collection.
CALDAV:min-date-time - when present this indicates the earliest
date and time (in UTC) that the server is willing to accept for
any DATE or DATE-TIME value in scheduling messages delivered to
the scheduling Inbox collection.
CALDAV:max-date-time - when present this indicates the latest date
and time (in UTC) that the server is willing to accept for any
DATE or DATE-TIME value in scheduling messages delivered to the
scheduling Inbox collection.
Daboo & Desruisseaux Expires December 21, 2009 [Page 15]
Internet-Draft CalDAV Scheduling Extensions June 2009
CALDAV:max-instances - when present this indicates the maximum
number of recurrence instances in scheduling messages delivered to
the scheduling Inbox collection.
CALDAV:max-attendees-per-instance - when present this indicates
the maximum number of ATTENDEE properties in any instance of
scheduling messages delivered to the scheduling Inbox collection.
4.3. Calendaring Reports Extensions
This specification extends the CALDAV:calendar-query and CALDAV:
calendar-multiget REPORTs to return results for calendar object
resources in scheduling Inbox collections when the report directly
targets such a collection. That is, the Request-URI for a report
MUST be the URI of the scheduling Inbox collection or of a child
resource within a scheduling Inbox collection. A report run on a
regular collection that includes a scheduling Inbox collection as a
child resource at any depth MUST NOT examine or return any calendar
object resources from within any scheduling Inbox collections.
When a CALDAV:calendar-query REPORT includes a time-range query and
targets a scheduling Inbox collection, if any calendar object
resources contain "VEVENT" calendar components that do not include a
"DTSTART" iCalendar property (as allowed by iTIP
[I-D.ietf-calsify-2446bis]) then such components MUST always match
the time-range query test.
Note that the CALDAV:free-busy-query REPORT is not supported on
scheduling Inbox collections.
Daboo & Desruisseaux Expires December 21, 2009 [Page 16]
Internet-Draft CalDAV Scheduling Extensions June 2009
5. Scheduling Transactions
When a calendar object resource is created, modified or removed from
a calendar collection (either via a PUT, DELETE, COPY or MOVE HTTP
request), the server examines the calendar data and checks to see
whether the data represents a scheduling object resource. If it
does, the server will automatically attempt to deliver a scheduling
message to the appropriate Calendar Users. Several types of
scheduling operation can occur in this case, equivalent to iTIP
"REQUEST", "REPLY", "CANCEL", and "ADD" operations.
5.1. Identifying Scheduling Object Resources
Calendar object resources on which the server performs automatic
scheduling transactons are refered to as scheduling object resources.
There are two types of scheduling object resources: organizer
scheduling object resources, and attendee scheduling object
resources.
A calendar object resource is considered to be a valid organizer
scheduling object resource if the "ORGANIZER" iCalendar property is
present and set in all the calendar components to a value that
matches one of the calendar user addresses of the owner of the
calendar collection.
A calendar object resource is considered to be a valid attendee
scheduling object resource if the "ORGANIZER" iCalendar property is
present and set in all the calendar components to the same value and
doesn't match one of the calendar user addresses of the owner of the
calendar collection, and that at least one of the "ATTENDEE"
iCalendar property values match one of the calendar user addresses of
the owner of the calendar collection.
The creation of attendee scheduling object resources is typically
done by the server, with the resource being stored in an appropriate
calendar collection.
5.2. Handling Scheduling Object Resources
The server's behavior when processing a scheduling object resource
depends on whether it is owned by the Organizer or an Attendee
specified in the calendar data.
5.2.1. Organizer Scheduling Object Resources
An Organizer can create, modify or remove a scheduling object
resource by issuing HTTP requests with an appropriate method. The
create, modify and remove behaviors for the server are each described
Daboo & Desruisseaux Expires December 21, 2009 [Page 17]
Internet-Draft CalDAV Scheduling Extensions June 2009
next, and the way these are invoked via HTTP requests is described in
Section 5.2.3.
5.2.1.1. Create
When a scheduling object resource is created by the Organizer, the
server will inspect each "ATTENDEE" property to determine if a
scheduling message should be delivered to this Attendee according to
the value of the "SCHEDULE-AGENT" property parameter (see
Section 10.1) as described in the table below:
+------------------+-------------+
| SCHEDULE-AGENT | iTIP METHOD |
+==================+=============+
| SERVER (default) | REQUEST |
+------------------+-------------+
| CLIENT | -- |
+------------------+-------------+
| NONE | -- |
+------------------+-------------+
The attempt to deliver the scheduling message will either succeed or
fail. In all cases, the server MUST add a "SCHEDULE-STATUS"
iCalendar property parameter (see Section 10.3) to the "ATTENDEE"
iCalendar property in the scheduling object resource being created,
and set its value as described in Section 9.2. This will result in
the created calendar object resource differing from the calendar data
sent in the HTTP request. As a result clients MAY reload the
calendar data from the server as soon as it is created on the server
in order to update to the new server generated state information.
Servers MUST NOT set the "SCHEDULE-STATUS" property parameter on the
"ATTENDEE" property of Attendees for which it did not attempt to
deliver a scheduling message.
Restrictions:
1. The server MAY reject any attempt to set the "PARTSTAT" iCalendar
property parameter value of the "ATTENDEE" iCalendar property of
other users in the calendar object resource to a value other than
"NEEDS-ACTION" if the "SCHEDULE-AGENT" property parameter value
is not present or set to the value "SERVER". To maintain
consistency across Organizers and Attendees, a server will
typically choose to enforce the requirement that only an Attendee
can change their own "PARTSTAT" to a value other than "NEEDS-
ACTION".
2. The server MAY reject attempts to create a scheduling object
resource that specifies a "UID" property value already specified
Daboo & Desruisseaux Expires December 21, 2009 [Page 18]
Internet-Draft CalDAV Scheduling Extensions June 2009
in a scheduling object resource contained in another calendar
collection of the Organizer.
3. The server MUST take into account scheduling privileges as
described in Section 13.1 when handling the creation of a
scheduling object resource.
4. Restrictions on calendar object resources defined in Section 4.1
of [RFC4791] MUST also be enforced.
5.2.1.2. Modify
When a scheduling object resource is modified by the Organizer, the
server will inspect each "ATTENDEE" property in the new calendar data
to determine which ones have the "SCHEDULE-AGENT" iCalendar property
parameter. It will then need to compare this with the "ATTENDEE"
properties in the existing calendar object resource that is being
modified.
For each Attendee in the old and new calendar data on a per-instance
basis, and taking into account the addition or removal of Attendees,
the server will determine whether to deliver a scheduling message to
the Attendee. The following table determines whether the server
needs to deliver a scheduling message, and if so which iTIP
scheduling method to use. The values "SERVER", "CLIENT", and "NONE"
in the top and left titles of the table refer to the "SCHEDULE-AGENT"
parameter value of the "ATTENDEE" property, and the values "<Absent>"
and "<Removed>" are used to cover the cases where the "ATTENDEE"
property is not present (Old) or is being removed (New).
+---------------+-----------------------------------------------+
| | New |
| ATTENDEE +-----------+-----------+-----------+-----------+
| | <Removed> | SERVER | CLIENT | NONE |
| | | (default) | | |
+===+===========+===========+===========+===========+===========+
| | <Absent> | -- | REQUEST / | -- | -- |
| | | | ADD | | |
| +-----------+-----------+-----------+-----------+-----------+
| | SERVER | CANCEL | REQUEST | CANCEL | CANCEL |
| O | (default) | | | | |
| l +-----------+-----------+-----------+-----------+-----------+
| d | CLIENT | -- | REQUEST / | -- | -- |
| | | | ADD | | |
| +-----------+-----------+-----------+-----------+-----------+
| | NONE | -- | REQUEST / | -- | -- |
| | | | ADD | | |
+---+-----------+-----------+-----------+-----------+-----------+
Daboo & Desruisseaux Expires December 21, 2009 [Page 19]
Internet-Draft CalDAV Scheduling Extensions June 2009
The attempt to deliver the scheduling message will either succeed or
fail. In all cases, the server MUST add a "SCHEDULE-STATUS"
iCalendar property parameter to the "ATTENDEE" iCalendar property in
the scheduling object resource being modified, and set its value as
described in Section 9.2. This will result in the created calendar
object resource differing from the calendar data sent in the HTTP
request. As a result clients MAY reload the calendar data from the
server as soon as it is modified on the server in order to update to
the new server generated state information.
Restrictions:
1. The server MAY reject any attempt to set the "PARTSTAT" iCalendar
property parameter value of the "ATTENDEE" iCalendar property of
other users in the calendar object resource to a value other than
"NEEDS-ACTION" if the "SCHEDULE-AGENT" property parameter value
is not present or set to the value "SERVER". To maintain
consistency for Organizers and Attendees, a server will typically
choose to enforce the requirement that only an Attendee can
change their own "PARTSTAT" to a value other than "NEEDS-ACTION".
2. The server MUST take into account scheduling privileges as
described in Section 13.1 when handling the modification of a
scheduling object resource.
3. Restrictions on calendar object resources defined in Section 4.1
of [RFC4791] MUST also be enforced.
5.2.1.3. Remove
When a scheduling object resource is removed by the Organizer, the
server will inspect each "ATTENDEE" property in the scheduling object
resource being removed to determine which ones have the "SCHEDULE-
AGENT" iCalendar property parameter.
For each Attendee the server will determine whether to attempt to
deliver a scheduling message into the Attendee's scheduling Inbox
collection, based on the table below:
+------------------+-------------+
| SCHEDULE-AGENT | iTIP METHOD |
+==================+=============+
| SERVER (default) | CANCEL |
+------------------+-------------+
| CLIENT | -- |
+------------------+-------------+
| NONE | -- |
+------------------+-------------+
Daboo & Desruisseaux Expires December 21, 2009 [Page 20]
Internet-Draft CalDAV Scheduling Extensions June 2009
Restrictions:
1. The server MUST take into account scheduling privileges as
described in Section 13.1 when handling the deletion of a
scheduling object resource.
5.2.2. Attendee Scheduling Object Resources
An Attendee can create, modify or remove a scheduling object resource
by issuing HTTP requests with an appropriate method. The create,
modify and remove behaviors for the server are each described next,
and the way these are invoked via HTTP requests is described in
Section 5.2.3.
5.2.2.1. Allowed Attendee Changes
Attendees are allowed to make some changes to a scheduling object
resource, though key properties such as start time, end time,
location, and summary are typically under the control of the
Organizer.
The server MUST allow Attendees to:
1. change their own "PARTSTAT" iCalendar property parameter value.
2. add, modify or remove any "TRANSP" iCalendar properties.
3. add, modify or remove any "PERCENT-COMPLETE" iCalendar
properties.
4. add, modify or remove any "VALARM" iCalendar components.
5. add, modify or remove the "CALSCALE" iCalendar property within
the top-level "VCALENDAR" component.
6. modify the "PRODID" iCalendar property within the top-level
"VCALENDAR" component.
7. add "EXDATE" iCalendar properties and possibly remove components
for overridden recurrence instances.
8. add, modify or remove any "CREATED", "DTSTAMP" and "LAST-
MODIFIED" iCalendar properties.
9. add new components to represent overridden recurrence instances,
provided the only changes to the recurrence instance follow the
rules above.
Daboo & Desruisseaux Expires December 21, 2009 [Page 21]
Internet-Draft CalDAV Scheduling Extensions June 2009
5.2.2.2. Create
Typically an Attendee does not create scheduling object resources, as
scheduling messages delivered to them on the server are automatically
processed by the server and placed on one of their calendars (see
Section 6). However, in some cases a scheduling message may get
delivered directly to the client, and the Attendee may wish to store
that on the server. In that case the client creates a scheduling
object resource in a suitable calendar belonging to the Attendee.
Once stored, it is then subject to the usual rules for attendee
scheduling object resources.
In some cases a server may not be able to process an Attendee
scheduling object resource that originated from another system (i.e.,
where the server is unable to deliver scheduling messages to the
Organizer). In such cases the server MUST add a "SCHEDULE-AGENT"
iCalendar property parameter to all "ORGANIZER" iCalendar properties
in the resource and set the value of each to "NONE". The server MAY
reject any attempt by the client to remove the "SCHEDULE-AGENT"
property parameter or change its value.
5.2.2.3. Modify
When a scheduling object resource is modified by an Attendee, the
server will inspect the changes by comparing it with the existing
scheduling object resource being replaced.
If the Attendee changes one or more "PARTSTAT" iCalendar property
values on any component, or adds an overridden component with a
changed "PARTSTAT" property, then the server MUST deliver an iTIP
"REPLY" scheduling message to the Organizer to indicate the new
participation status of the Attendee.
The attempt to deliver the scheduling message will either succeed or
fail. In all cases, the server MUST add a "SCHEDULE-STATUS"
iCalendar property parameter to the "ORGANIZER" iCalendar property in
the scheduling object resource being created, and set its value as
described in Section 9.2. This will result in the created calendar
object resource differing from the calendar data sent in the HTTP
request. As a result clients MAY reload the calendar data from the
server as soon as it is stored in order to update to the new server
generated state information.
5.2.2.4. Remove
When a scheduling object resource is removed by the Attendee, one of
two possibilities exist:
Daboo & Desruisseaux Expires December 21, 2009 [Page 22]
Internet-Draft CalDAV Scheduling Extensions June 2009
1. If the HTTP request contains a "Schedule-Reply" request header
set to the value "T" or there is no "Schedule-Reply" request
header, then the server MUST attempt to deliver a scheduling
message to the Organizer indicating that the Attendee has a
"PARTSTAT" iCalendar property parameter value set to "DECLINED".
That is, the Attendee has chosen not to attend any instances. If
the server is unable to deliver the scheduling message, the
remove action MUST fail, and an appropriate "SCHEDULE-STATUS"
iCalendar property parameter set on the "ORGANIZER" property in
the scheduling object resource stored by the server.
2. If the HTTP request contains a request header "Schedule-Reply"
set to the value "F", the server MUST NOT attempt to deliver a
scheduling message. The resource is simply removed. This
provides the client a way to silently remove unwanted scheduling
attempts.
5.2.3. HTTP Methods
This section describes how use of various HTTP methods on a
scheduling object resource will cause a create, modify or remove
action on that resource as described above. The use of these methods
is subject to the restrictions in [RFC4791], in addition to what is
described below.
5.2.3.1. PUT
When a PUT method request is received, the server will execute the
following actions, provided all appropriate preconditions are met:
+--------------------------+--------------------------+-------------+
| Existing Destination | Resulting Destination | Server |
| Resource | Resource | Action |
+--------------------------+--------------------------+-------------+
| None | Calendar object resource | None |
| | | |
| None | Scheduling object | Create |
| | resource | |
| | | |
| Calendar object resource | Calendar object resource | None |
| | | |
| Calendar object resource | Scheduling object | Create |
| | resource | |
| | | |
| Scheduling object | Calendar object resource | Remove |
| resource | | |
| | | |
Daboo & Desruisseaux Expires December 21, 2009 [Page 23]
Internet-Draft CalDAV Scheduling Extensions June 2009
| Scheduling object | Scheduling object | Modify |
| resource | resource | |
+--------------------------+--------------------------+-------------+
5.2.3.2. COPY
When a COPY method request is received, the server will execute the
following actions based on the source and destination collections in
the request:
+-------------------------+-------------------------+---------------+
| Source Collection | Destination Collection | Server Action |
+-------------------------+-------------------------+---------------+
| Non-calendar collection | Non-calendar collection | None |
| | | |
| Non-calendar collection | Calendar collection | (1) |
| | | |
| Calendar collection | Non-calendar collection | None |
| | | |
| Calendar collection | Calendar collection | None |
+-------------------------+-------------------------+---------------+
Note 1. The same rules as used for PUT above are applied for the
destination of the COPY request.
5.2.3.3. MOVE
When a MOVE method request is received, the server will execute the
following actions based on the source and destination collections in
the request:
+-------------------------+-------------------------+---------------+
| Source Collection | Destination Collection | Server Action |
+-------------------------+-------------------------+---------------+
| Non-calendar collection | Non-calendar collection | None |
| | | |
| Non-calendar collection | Calendar collection | (1) |
| | | |
| Calendar collection | Non-calendar collection | (2) |
| | | |
| Calendar collection | Calendar collection | None |
+-------------------------+-------------------------+---------------+
Note 1. The same rules as used for PUT above are applied for the
destination of the MOVE request.
Note 2. The same rules as used for DELETE below are applied for the
source of the MOVE request.
Daboo & Desruisseaux Expires December 21, 2009 [Page 24]
Internet-Draft CalDAV Scheduling Extensions June 2009
5.2.3.4. DELETE
When a DELETE method is targeted at a scheduling object resource the
server will execute the Remove action.
When a DELETE method is targeted at a calendar collection the server
will execute the Remove action on all scheduling object resources
contained in the calendar collection.
5.2.4. Additional Method Preconditions
This specification defines additional method preconditions (see
Section 16 of WebDAV [RFC4918]) to provide machine-parsable
information in error responses.
5.2.4.1. CALDAV:unique-scheduling-object-resource Precondition
Name: unique-scheduling-object-resource
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: PUT, COPY, and MOVE
Use with: 409 Conflict
Purpose: (precondition) -- Servers MAY reject requests to create a
scheduling object resource with an iCalendar "UID" property value
already in use by another scheduling object resource owned by the
same user in other calendar collections. Servers SHOULD report
the URL of the scheduling object resource that is already making
use of the same "UID" property value in the DAV:href element.
Definition:
<!ELEMENT unique-scheduling-object-resource (DAV:href?)>
Example:
<C:unique-scheduling-object-resource xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:href>/home/bernard/calendars/personal/abc123.ics</D:href>
</C:unique-scheduling-object-resource>
5.2.4.2. CALDAV:same-organizer-in-all-components Precondition
Daboo & Desruisseaux Expires December 21, 2009 [Page 25]
Internet-Draft CalDAV Scheduling Extensions June 2009
Name: same-organizer-in-all-components
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: PUT, COPY, and MOVE
Use with: 409 Conflict
Purpose: (precondition) -- All the calendar components in a
scheduling object resource MUST contain the same "ORGANIZER"
property value when present.
Definition:
<!ELEMENT same-organizer-in-all-components EMPTY>
Example:
<C:same-organizer-in-all-components
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
5.2.4.3. CALDAV:allowed-organizer-scheduling-object-change Precondition
Name: allowed-organizer-scheduling-object-change
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: PUT, COPY, and MOVE
Use with: 409 Conflict
Purpose: (precondition) -- Servers MAY impose restrictions on
modifications allowed by an Organizer. For instance, servers MAY
prevent the Organizer setting the "PARTSTAT" property parameter to
a value other than "NEEDS-ACTION" if the corresponding "ATTENDEE"
property has the "SCHEDULE-AGENT" property parameter set to
"SERVER", or has no "SCHEDULE-AGENT" property parameter. See
Section 5.2.1.
Definition:
<!ELEMENT allowed-organizer-scheduling-object-change EMPTY>
Example:
<C:allowed-organizer-scheduling-object-change
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
Daboo & Desruisseaux Expires December 21, 2009 [Page 26]
Internet-Draft CalDAV Scheduling Extensions June 2009
5.2.4.4. CALDAV:allowed-attendee-scheduling-object-change Precondition
Name: allowed-attendee-scheduling-object-change
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: PUT, COPY, and MOVE
Use with: 409 Conflict
Purpose: (precondition) -- Servers MAY impose restrictions on
modifications allowed by an Attendee. Attendee modifications that
servers MUST allow are specified in Section 5.2.2.1.
Definition:
<!ELEMENT allowed-attendee-scheduling-object-change EMPTY>
Example:
<C:allowed-attendee-scheduling-object-change
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
5.2.5. DTSTAMP and SEQUENCE Properties
Whenever the server generates a scheduling message for delivery to a
Calendar User, it MUST ensure that a "DTSTAMP" iCalendar property is
present and MUST set the value to the UTC time that the scheduling
message was generated (as required by iCalendar).
iTIP [I-D.ietf-calsify-2446bis] places certain requirements on how
the "SEQUENCE" iCalendar property value in scheduling messages
changes. The server MUST ensure that for each type of scheduling
operation, the "SEQUENCE" iCalendar property value is appropriately
updated. If the client does not update the "SEQUENCE" iCalendar
property itself when that is required, the server MUST update the
property.
5.2.6. Limit Recurrence Instances Sent to Attendees
When delivering scheduling messages for recurring calendar components
to Attendees, servers MUST ensure that Attendees only get information
about recurrence instances that explicitly include them as an
Attendee.
For example, if an Attendee is invited to a single recurrence
instance of a recurring event, and no others, the scheduling object
resource contained in the Organizer's calendar collection will
Daboo & Desruisseaux Expires December 21, 2009 [Page 27]
Internet-Draft CalDAV Scheduling Extensions June 2009
contain an overridden instance in the form of a separate calendar
component. That separate calendar component will include the
"ATTENDEE" property referencing the "one-off" Attendee. That
Attendee will not be listed in any other calendar components in the
scheduling object resource. The scheduling message that will be
delivered to the Attendee will only contain information about this
overridden instance.
As another example, an Attendee could be excluded from one instance
of a recurring event. In that case the scheduling object resource
contained in the calendar collection of the Organizer will include an
overridden instance with an "ATTENDEE" list that does not include the
Attendee being excluded. The scheduling message that will be
delivered to the Attendee will not specify the overridden instance
but rather include an "EXDATE" property in the master recurring
component defining the recurrence set.
5.2.7. Forcing the Server to Send a Scheduling Message
The iCalendar property parameter "SCHEDULE-FORCE-SEND" defined in
Section 10.2 can be used by a Calendar User to force the server to
send a scheduling message to an Attendee or the Organizer in a
situation where the server would not normally send a scheduling
message. For instance, an Organizer could use this property
parameter to request an Attendee, that previously declined an
invitation, to reconsider their participation status without being
forced to modify the event.
Daboo & Desruisseaux Expires December 21, 2009 [Page 28]
Internet-Draft CalDAV Scheduling Extensions June 2009
6. Processing Incoming Scheduling Messages
Scheduling operations can cause the delivery of a scheduling message
into an Organizer's or Attendee's scheduling Inbox collection. In
the former case the scheduling messages are replies from Attendees,
in the latter case the scheduling messages are requests,
cancellations or additions from the Organizer.
The server will automatically process incoming scheduling messages
and make them available in the scheduling Inbox collection as an
indicator to the client that a scheduling operation has taken place.
The server MUST take into account privileges on the scheduling Inbox
collection, when processing incoming scheduling messages, to
determine whether delivery of the scheduling message is allowed.
Privileges on calendars containing any matching scheduling object
resource are not considered in this case. Additionally, servers MUST
take into account any scheduling Inbox collection preconditions (see
Section 4.2) when delivering the scheduling message, and it MUST take
into account the similar preconditions on any calendar collection
which contains, or would contain, the corresponding scheduling object
resource.
6.1. Processing Attendee Replies
For a scheduling message reply sent by an Attendee, the server first
locates the corresponding scheduling object resource belonging to the
Organizer.
The server MUST then update the "PARTSTAT" iCalendar property
parameter value of each "ATTENDEE" iCalendar property in the
scheduling object resource to match the changes indicated in the
reply (taking into account the fact that an Attendee could have
created a new overridden iCalendar component to indicate different
participation status on one or more recurrence instances of a
recurring event).
The server MUST also update or add the "SCHEDULE-STATUS" property
parameter on each matching "ATTENDEE" iCalendar property and sets its
value to that of the "REQUEST-STATUS" property in the reply, or to
"2.0" if "REQUEST-STATUS" is not present (also taking into account
recurrence instances). If there are multiple "REQUEST-STATUS"
properties in the reply, the "SCHEDULE-STATUS" property parameter
value is set to a comma-separated list of status codes, one from each
"REQUEST-STATUS" property.
The server SHOULD send scheduling messages to all the other Attendees
indicating the change in participation status of the Attendee
Daboo & Desruisseaux Expires December 21, 2009 [Page 29]
Internet-Draft CalDAV Scheduling Extensions June 2009
replying, subject to the recurrence requirements of Section 5.2.6.
In this case, the scheduling message MUST only appear in the
Organizer's scheduling Inbox collection once all automatic processing
has been done.
6.2. Processing Organizer Requests, Additions, and Cancellations
For a scheduling message sent by an Organizer, the server first tries
to locate a corresponding scheduling object resource belonging to the
Attendee. If no matching scheduling object resource exists, the
server treats the scheduling message as a new message, otherwise it
is treated as an update.
In the case of a new message, the server MUST process the scheduling
message and create a new scheduling object resource in an appropriate
calendar collection for the Attendee.
In the case of an update, the server MUST process the scheduling
message and update the matching scheduling object resource belonging
to the Attendee to reflect the changes sent by the Organizer.
In any case, the scheduling message MUST only appear in the
Attendee's scheduling Inbox collection once all automatic processing
has been done.
6.3. Default Calendar Collection
The server is REQUIRED to process scheduling messages that specify a
request for a new calendar component received for an Attendee by
creating a new scheduling object resource in a calendar collection
belonging to the Attendee. A Calendar User who can participate as an
Attendee in a scheduling operation MUST have at least one valid
calendar collection available. If there is no valid calendar
collection, then the server MUST reject the attempt to deliver the
scheduling message to the Attendee.
Servers MAY provide support for a default calendar collection, that
is, the calendar collection in which new scheduling object resources
will be created on reception of scheduling messages that specify a
request for a new calendar component. The CALDAV:schedule-default-
calendar-URL WebDAV property, which MAY be defined on the scheduling
Inbox collection of a Calendar User, specifies if this Calendar User
has a default calendar collection. See Section 12.2.
Servers MUST create new scheduling object resources in the default
calendar collection, if the CALDAV:schedule-default-calendar-URL
WebDAV property is set.
Daboo & Desruisseaux Expires December 21, 2009 [Page 30]
Internet-Draft CalDAV Scheduling Extensions June 2009
Servers MAY allow clients to change the default calendar collection
by changing the value of the CALDAV:schedule-default-calendar-URL
WebDAV property on the scheduling Inbox collection. However, they
MUST ensure that any new value stored for that property refers to a
valid calendar collection belonging to the owner of the scheduling
inbox collection.
Servers MUST reject any attempt to delete the default calendar
collection.
6.3.1. Additional Method Preconditions
This specification defines additional method preconditions (see
Section 16 of WebDAV [RFC4918]) to provide machine-parsable
information in error responses.
6.3.1.1. CALDAV:default-calendar-delete-allowed Precondition
Name: default-calendar-delete-allowed
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: DELETE
Use with: 403 Forbidden
Purpose: (precondition) -- The client attempted to delete the
calendar collection currently referenced by the CALDAV:schedule-
default-calendar-URL property, or attempted to remove the CALDAV:
schedule-default-calendar-URL property on the scheduling Inbox
collection on a server that doesn't allow such operations.
Definition:
<!ELEMENT default-calendar-delete-allowed EMPTY>
Example:
<C:default-calendar-delete-allowed
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
6.3.1.2. CALDAV:valid-schedule-default-calendar-URL Precondition
Name: valid-schedule-default-calendar-URL
Daboo & Desruisseaux Expires December 21, 2009 [Page 31]
Internet-Draft CalDAV Scheduling Extensions June 2009
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: PROPPATCH
Use with: 403 Forbidden
Purpose: (precondition) -- The client attempted to set the CALDAV:
schedule-default-calendar-URL property to a DAV:href element that
doesn't reference a valid calendar collection. Note: Servers that
don't allow clients to change the CALDAV:schedule-default-
calendar-URL property would simply return the DAV:cannot-modify-
protected-property precondition defined in Section 16 of WebDAV
[RFC4918].
Definition:
<!ELEMENT valid-schedule-default-calendar-URL EMPTY>
Example:
<C:valid-schedule-default-calendar-URL
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
6.4. Scheduling Messages as Notifications
Once the processing of an incoming scheduling message is completed by
the server, the message is made available as a child resource in the
scheduling Inbox collection of the Calendar User that received the
message, to serve as a notification that a change has been made to
the corresponding scheduling object resource. Scheduling messages
are typically removed from the scheduling Inbox collection by the
client once it has acknowledged the change.
Daboo & Desruisseaux Expires December 21, 2009 [Page 32]
Internet-Draft CalDAV Scheduling Extensions June 2009
7. Request for Busy Time Information
The POST method is used to request busy time information of one or
more Calendar Users by targeting the request at a scheduling Outbox
collection. The request body of a POST method MUST contain a
"VFREEBUSY" calendar compoment with the "METHOD" iCalendar property
set to the value "REQUEST" as specified in Section 3.3.2 of iTIP
[I-D.ietf-calsify-2446bis]. The resource identified by the Request-
URI MUST be a resource collection of type CALDAV:schedule-outbox
(Section 4.1).
7.1. Status Codes
The following are examples of response codes one would expect to be
used for this method. Note, however, that unless explicitly
prohibited any 2/3/4/5xx series response code may be used in a
response.
200 (OK) - The command succeeded.
204 (No Content) - The command succeeded.
400 (Bad Request) - The client has provided an invalid scheduling
message.
403 (Forbidden) - The client cannot submit a scheduling message to
the specified Request-URI.
404 (Not Found) - The URL in the Request-URI was not present.
423 (Locked) - The specified resource is locked and the client
either is not a lock owner or the lock type requires a lock token
to be submitted and the client did not submit it.
7.2. Additional Method Preconditions
This specification defines additional method preconditions for the
POST method. Preconditions defined in WebDAV ACL [RFC3744] and
CalDAV [RFC4791] that applies to the POST method are also listed here
for completeness.
7.2.1. DAV:need-privileges Precondition
Name: need-privileges
Daboo & Desruisseaux Expires December 21, 2009 [Page 33]
Internet-Draft CalDAV Scheduling Extensions June 2009
Namespace: DAV:
Apply to: POST
Use with: 403 Forbidden
Purpose: (precondition) -- The currently authenticated user MUST be
granted the CALDAV:schedule-send or CALDAV:schedule-send-freebusy
privilege on the scheduling Outbox collection being targeted by
the request.
Definition:
<!ELEMENT DAV:need-privileges (DAV:resource)* >
<!ELEMENT DAV:resource (DAV:href, DAV:privilege) >
Example:
<D:need-privileges xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
<D:resource>
<D:href>/home/bernard/calendars/outbox/</D:href>
<D:privilege><C:schedule-send-freebusy/></D:privilege>
</D:resource>
</D:need-privileges>
7.2.2. CALDAV:supported-collection Precondition
Name: supported-collection
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: POST
Use with: 400 Bad Request
Purpose: (precondition) -- The Request-URI MUST identify the
location of a scheduling Outbox collection.
Definition:
<!ELEMENT supported-collection EMPTY >
Example:
<C:supported-collection xmlns:C="urn:ietf:params:xml:ns:caldav"/>
Daboo & Desruisseaux Expires December 21, 2009 [Page 34]
Internet-Draft CalDAV Scheduling Extensions June 2009
7.2.3. CALDAV:supported-calendar-data Precondition
Name: supported-calendar-data
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: POST
Use with: 400 Bad Request
Purpose: (precondition) -- The resource body submitted in the POST
request MUST be a supported media type (e.g., text/calendar).
Definition:
<!ELEMENT supported-calendar-data EMPTY >
Example:
<C:supported-calendar-data
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
7.2.4. CALDAV:valid-calendar-data Precondition
Name: valid-calendar-data
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: POST
Use with: 400 Bad Request
Purpose: (precondition) -- The resource submitted in the POST
request MUST be valid data for the media type being specified
(e.g., a valid iCalendar object).
Definition:
<!ELEMENT valid-calendar-data EMPTY>
Example:
<C:valid-calendar-data xmlns:C="urn:ietf:params:xml:ns:caldav"/>
Daboo & Desruisseaux Expires December 21, 2009 [Page 35]
Internet-Draft CalDAV Scheduling Extensions June 2009
7.2.5. CALDAV:valid-scheduling-message Precondition
Name: valid-scheduling-message
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: POST
Use with: 400 Bad Request
Purpose: (precondition) -- The resource submitted in the POST
request MUST obey all restrictions specified for the POST request
(e.g., the scheduling message follow the restrictions of iTIP).
Definition:
<!ELEMENT valid-scheduling-message EMPTY >
Example:
<C:valid-scheduling-message
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
7.2.6. CALDAV:organizer-allowed Precondition
Name: organizer-allowed
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: POST
Use with: 409 Conflict
Purpose: (precondition) -- The Calendar User identified by the
"ORGANIZER" property in the POST request's scheduling message MUST
be the Calendar User (or one of the Calendar Users) associated
with the scheduling Outbox collection being targeted by the
request;
Definition:
<!ELEMENT organizer-allowed EMPTY >
Example:
<C:organizer-allowed xmlns:C="urn:ietf:params:xml:ns:caldav"/>
Daboo & Desruisseaux Expires December 21, 2009 [Page 36]
Internet-Draft CalDAV Scheduling Extensions June 2009
7.2.7. CALDAV:max-resource-size Precondition
Name: max-resource-size
Namespace: urn:ietf:params:xml:ns:caldav
Apply to: POST
Use with: 403 Forbidden
Purpose: (precondition) -- The resource submitted in the POST
request MUST have an octet size less than or equal to the value of
the CALDAV:max-resource-size property (defined in Section 5.2.5 of
[RFC4791]) specified on the scheduling Outbox collection targeted
by the request.
Definition:
<!ELEMENT max-resource-size EMPTY >
Example:
<C:max-resource-size xmlns:C="urn:ietf:params:xml:ns:caldav"/>
7.3. Response to a POST request
A POST request may deliver a scheduling message to one or more
Calendar Users. Since the behavior of each recipient may vary, it is
useful to get response status information for each recipient in the
overall POST response. This specification defines a new XML response
to convey multiple recipient status.
A response to a POST method that indicates status for one or more
recipients MUST be a CALDAV:schedule-response XML element. This MUST
contain one or more CALDAV:response elements for each recipient, with
each of those containing elements that indicate which recipient they
correspond to, the scheduling status for that recipient, any error
codes and an optional description. See Section 14.1.
In the case of a freebusy request, the CALDAV:response elements can
also contain CALDAV:calendar-data elements which contain freebusy
information (e.g., an iCalendar VFREEBUSY component) indicating the
busy state of the corresponding recipient, assuming that the freebusy
request for that recipient succeeded. See Appendix B.5 for an
example freebusy request and response.
Daboo & Desruisseaux Expires December 21, 2009 [Page 37]
Internet-Draft CalDAV Scheduling Extensions June 2009
8. Conditional Requests on Scheduling Object Resources
Because replies from Attendees and updates from Organizers are
automatically processed by the server, clients might be in a
situation where their copy of a calendar resource is different from
the one currently on the server. When an Attendee or Organizer makes
a change to the client's copy of the calendar resource, if the client
writes the data to the server it could overwrite the changes already
made there. Typically, HTTP clients use the ETag value and If-Match
request header to avoid the "lost update problem".
Calendar user agents can also use ETag and If-Match to avoid this
problem. However, when doing so the client will likely have to
resolve the differences between the new resource and the original
one, and the changes made by the Attendee or Organizer in the client.
This can be a complicated comparison particularly when recurring
components are present.
Additionally, the data on the server may change frequently as
Attendees change their participation status, triggering updates to
the Organizer and consequently other Attendees' copies of the
scheduling object resource. If the ETag/If-Match behavior were used,
clients would be forced to reconcile their cached copy of a
scheduling object resource with the updated one on the server in
order to attempt to write the user's changes back. This could lead
to a race condition that can effectively result in a temporary denial
of service when, for example, there is an event with a large Attendee
list. A "storm" of updates will occur if Attendees all start
responding at the same time, and this would prevent Attendees and the
Organizer from being able to update their own copies of the
scheduling object resource as the server copy is changing frequently.
What would be preferable is having the server determine the best way
to merge changes made on the server with changes being made by the
client. For example, if an Attendee changes their participation
status and triggers an update to the Organizer's copy of the event,
but the Organizer also updates their cached copy of the event and
attempts to write it back, rather than failing on a conditional If-
Match when the Organizer writes their data, the server would instead
take the changes made by the Organizer and apply the Attendee changes
and store the result. Thus a form of "weak" ETag matching behavior
is needed such that scheduling changes made automatically on the
server do not invalidate the tag, so that when clients store data
conditionally based on the tag value, the server knows it can apply
the merge behavior.
In order to do that, this specification introduces a new WebDAV
resource property CALDAV:schedule-tag with a corresponding response
Daboo & Desruisseaux Expires December 21, 2009 [Page 38]
Internet-Draft CalDAV Scheduling Extensions June 2009
header "Schedule-Tag", and a new "If-Schedule-Tag-Match" request
header to allow client changes to be appropriately merged with server
changes in the case where the changes on the server were the result
of an "inconsequential" scheduling message update. An
"inconsequential" scheduling message is one which simply updates the
status information of Attendees due to a reply from an Attendee.
Servers MUST support conditional requests targeted at scheduling
object resources using the "If-Schedule-Tag-Match" request header.
Consequently, the server MUST support the "Schedule-Tag" response
header and CALDAV:schedule-tag property for scheduling object
resources. Servers MUST automatically resolve conflicts with
"inconsequential" changes done to scheduling object resources when
the "If-Schedule-Tag-Match" request header is specified.
The If-Schedule-Tag-Match request header applies only to the Request-
URI, and not to the Destination of a COPY or MOVE in the same way as
the If-Match request header.
Clients SHOULD use conditional requests using the If-Schedule-Tag-
Match request header.
A response to any successful GET or PUT request targeting a
scheduling object resource MUST include a Schedule-Tag response
header with the value set to the same value as the CALDAV:schedule-
tag WebDAV property of the resource.
A response to any successful COPY or MOVE request that specifies a
Destination request header targeting a scheduling object resource
MUST include a Schedule-Tag response header with the value set to the
same value as the CALDAV:schedule-tag WebDAV property of the resource
identified in the Request-URI.
The Schedule-Tag feature is designed to be used to address the
problem of "inconsequential" changes on the server only. Normal ETag
operations are used in all other cases, e.g., for synchronization.
The value of the CALDAV:schedule-tag property changes according to
these rules:
o For an Organizer's copy of a scheduling object resource:
1. The server MUST NOT change the CALDAV:schedule-tag property
value when the scheduling object resource is updated as the
result of automatically processing a scheduling message reply
from an Attendee. For instance, when an Attendee replies to
the Organizer, the CALDAV:schedule-tag property is unchanged
after the Organizer's scheduling object resource has been
Daboo & Desruisseaux Expires December 21, 2009 [Page 39]
Internet-Draft CalDAV Scheduling Extensions June 2009
automatically updated by the server with the Attendee's new
participation status.
2. The server MUST change CALDAV:schedule-tag property value when
the schedulng object resource is changed directly via an HTTP
request (e.g., PUT, COPY or MOVE).
o For an Attendee's copy of a scheduling object resource:
1. The server MUST change the CALDAV:schedule-tag property value
when the scheduling object resource is changed as the result
of processing a scheduling message update from an Organizer
that contains changes other than just the participation status
of Attendees.
2. The server MUST NOT change the CALDAV:schedule-tag property
value when the scheduling object resource is changed as the
result of processing a scheduling message update from an
Organizer that only specify changes in the participation
status of Attendees. For instance, when Attendee "A" replies
to Organizer "O", and Attendee "B" receives a scheduling
message update from Organizer "O" with the new participation
status of Attendee "A", the CALDAV:schedule-tag property of
Attendee "B"s scheduling object resource MUST NOT be changed.
3. The server MUST change the CALDAV:schedule-tag property value
when the scheduling object resource is changed directly via an
HTTP request (e.g., PUT, COPY or MOVE).
8.1. PUT
Clients can use the If-Schedule-Tag-Match request header to do a
conditional PUT request that ensures that "inconsequential" changes
on the server do not result in a precondition error. The value of
the request header is set to the last Schedule-Tag value received for
the resource being modified. If the value of the If-Schedule-Tag-
Match header matches the current value of the CALDAV:schedule-tag
property the server MUST take any "ATTENDEE" property changes for all
Attendees other than the owner of the scheduling object resource and
apply those to the new resource being stored. Otherwise, the server
MUST fail the request with a 412 Precondition Failed status code.
8.2. DELETE
Clients can use the If-Schedule-Tag-Match request header to do a
conditional DELETE request that ensures that "inconsequential"
changes on the server do not result in a precondition error. The
value of the request header is set to the last Schedule-Tag value
Daboo & Desruisseaux Expires December 21, 2009 [Page 40]
Internet-Draft CalDAV Scheduling Extensions June 2009
received for the resource being deleted. If the value of the If-
Schedule-Tag-Match header matches the current value of the CALDAV:
schedule-tag property the server performs the normal DELETE request
processing for the resource. Otherwise, the server MUST fail the
request with a 412 Precondition Failed status code.
8.3. COPY or MOVE
Clients can use the If-Schedule-Tag-Match request header to do
conditional COPY or MOVE requests that ensures that "inconsequential"
changes on the server do not result in a precondition error. The
value of the request header is set to the last Schedule-Tag value
received for the resource being copied or moved. If the value of the
If-Schedule-Tag-Match header matches the current value of the CALDAV:
schedule-tag property the server performs the normal COPY or MOVE
request processing for the resource. Otherwise, the server MUST fail
the request with a 412 Precondition Failed status code.
Daboo & Desruisseaux Expires December 21, 2009 [Page 41]
Internet-Draft CalDAV Scheduling Extensions June 2009
9. Other Scheduling Considerations
9.1. Attendee Participation Status
This section specifies additional requirements on the handling of the
"PARTSTAT" property parameter when the "SCHEDULE-AGENT" property
parameter on the corresponding "ATTENDEE" property is set to the
value "SERVER" or is not present.
Clients SHOULD, and servers MUST reset the "PARTSTAT" property
parameter value of all "ATTENDEE" properties, except the one that
corresponds to the Organizer, to "NEEDS-ACTION" when the Organizer
reschedules an event.
A reschedule of an event occurs when any "DTSTART", "DTEND",
"DURATION", "DUE", "RRULE", "RDATE", or "EXDATE" property changes in
a calendar component such that existing recurrence instances are
impacted by the changes, as shown in the table below.
+----------+--------------------------------------------------------+
| Property | Description |
+----------+--------------------------------------------------------+
| DTSTART | Any change to these properties MUST result in |
| DTEND | "PARTSTAT" being set to "NEEDS-ACTION" |
| DURATION | |
| DUE | |
| | |
| | |
| | |
| RRULE | A change to or addition of this property that results |
| | in the addition of new recurring instances or a change |
| | in time for existing recurring instances MUST result |
| | in "PARTSTAT" being reset to "NEEDS-ACTION" on each |
| | affected component. |
| | |
| | |
| | |
| RDATE | A change to or addition of this property that results |
| | in the addition of new recurring instances or a change |
| | in time for existing recurring instances MUST result |
| | in "PARTSTAT" being reset to "NEEDS-ACTION" on each |
| | affected component. |
| | |
| | |
| | |
Daboo & Desruisseaux Expires December 21, 2009 [Page 42]
Internet-Draft CalDAV Scheduling Extensions June 2009
| EXDATE | A change to or removal of this property that results |
| | in the re-instatement of recurring instances MUST |
| | result in "PARTSTAT" being reset to "NEEDS-ACTION" on |
| | each affected component. |
+----------+--------------------------------------------------------+
The server MAY allow the Organizer's client to change an Attendee's
"PARTSTAT" property parameter value to "NEEDS-ACTION" at any other
time (e.g., when the "LOCATION" property value changes, an Organizer
might wish to re-invite Attendees who may be impacted by the change).
9.2. Schedule Status Values
When scheduling with an Attendee there are two types of status
information that can be returned during the transaction. The first
status information is a "delivery" status that indicates whether the
scheduling message from the Organizer to the Attendee was delivered
or not, or what the current status of delivery is. The second status
information is a "reply" status corresponding to the Attendee's own
"REQUEST-STATUS" information from the scheduling message reply that
is sent back to the Organizer.
Similarly, when an Attendee sends a reply back to the Organizer,
there will be "delivery" status information for the scheduling
message sent to the Organizer. However, there is no "REQUEST-STATUS"
sent back by the Organizer, so there is no equivalent of the "reply"
status as per scheduling messages to Attendees.
The "delivery" status information on an "ORGANIZER" or "ATTENDEE"
iCalendar property is conveyed in the "SCHEDULE-STATUS" property
parameter value (Section 10.3). The status code value for "delivery"
status can be one of the following:
Daboo & Desruisseaux Expires December 21, 2009 [Page 43]
Internet-Draft CalDAV Scheduling Extensions June 2009
+----------+--------------------------------------------------------+
| Delivery | Description |
| Status | |
| Code | |
+----------+--------------------------------------------------------+
| 1.0 | The scheduling message is pending. i.e. the server is |
| | still in the process of sending the message. The |
| | status code value can be expected to change once the |
| | server has completed its sending and delivery |
| | attempts. |
| | |
| | |
| | |
| 1.1 | The scheduling message has been successfully sent. |
| | However, the server does not have explicit information |
| | about whether the scheduling message was successfully |
| | delivered to the recipient. This state can occur with |
| | "store and forward" style scheduling protocols such as |
| | iMIP [I-D.ietf-calsify-rfc2447bis] (iTIP using email). |
| | |
| | |
| | |
| 1.2 | The scheduling message has been successfully |
| | delivered. |
| | |
| | |
| | |
| 3.7 | The scheduling message was not delivered because the |
| | server did not recognize the calendar user address as |
| | a valid calendar user. |
| | |
| | |
| | |
| 3.8 | The scheduling message was not delivered due to |
| | insufficient privileges. |
| | |
| | |
| | |
| 5.1 | The scheduling message was not delivered because the |
| | server could not complete delivery of the message. |
| | This is likely due to a temporary failure, and the |
| | originator can try to send the message again at a |
| | later time. |
| | |
| | |
| | |
Daboo & Desruisseaux Expires December 21, 2009 [Page 44]
Internet-Draft CalDAV Scheduling Extensions June 2009
| 5.2 | The scheduling message was not delivered because the |
| | server was not able to find a suitable way to deliver |
| | the message. This is likely a permanent failure, and |
| | the originator should not try to send the message |
| | again, at least without verifying/correcting the |
| | calendar user address of the recipient. |
| | |
| | |
| | |
| 5.3 | The scheduling message was not delivered and was |
| | rejected because scheduling with that recipient is not |
| | allowed. This is likely a permanent failure, and the |
| | originator should not try to send the message again. |
+----------+--------------------------------------------------------+
The status code for "reply" status can be any of the valid iTIP
[I-D.ietf-calsify-2446bis] "REQUEST-STATUS" values.
9.3. Organizer is an Attendee
The Organizer of a scheduled event may also be an Attendee of that
event. In such cases the server MUST NOT send a scheduling message
to the Attendee that matches the Organizer.
Daboo & Desruisseaux Expires December 21, 2009 [Page 45]
Internet-Draft CalDAV Scheduling Extensions June 2009
10. Additional iCalendar Property Parameters
This specification defines additional iCalendar property parameters
to support the CalDAV scheduling extensions.
10.1. Schedule Agent Parameter
Parameter Name: SCHEDULE-AGENT
Purpose: To specify the agent expected to deliver scheduling
messages to the corresponding Organizer or Attendee.
Format Definition: This property parameter is defined by the
following notation:
scheduleagentparam = "SCHEDULE-AGENT" "="
("SERVER" ; The server handles scheduling
/ "CLIENT" ; The client handles scheduling
/ "NONE" ; No automatic scheduling
/ x-name ; Experimental type
/ iana-token) ; Other IANA registered type
;
; Default is SERVER
Description: This property parameter MAY be specified on "ORGANIZER"
or "ATTENDEE" iCalendar properties. In the absence of this
parameter, the value "SERVER" MUST be used for the default
behavior. The value determines whether or not an automatic
scheduling transaction on a server will cause a scheduling message
to be sent to the corresponding Calendar User identified by the
"ORGANIZER" or "ATTENDEE" property value. When the value "SERVER"
is specified, or the parameter is absent, then it is the server's
responsibility to send a scheduling message as part of an
automatic scheduling transaction. When the value "CLIENT" is
specified, that indicates that the client is handling scheduling
messages with the Calendar User itself. When "NONE" is specified,
no scheduling messages are being sent to the Calendar User.
Servers MUST NOT include this parameter in any scheduling messages
sent as the result of an automatic scheduling transaction.
Clients SHOULD NOT include this parameter in any scheduling
messages that they themselves send.
Servers and clients MUST treat x-name and iana-token values they
don't recognize the same way as they would the "NONE" value.
Daboo & Desruisseaux Expires December 21, 2009 [Page 46]
Internet-Draft CalDAV Scheduling Extensions June 2009
Example:
ATTENDEE;SCHEDULE-AGENT=SERVER:mailto:bernard@example.com
ATTENDEE;SCHEDULE-AGENT=NONE:mailto:cyrus@example.com
10.2. Schedule Force Send Parameter
Parameter Name: SCHEDULE-FORCE-SEND
Purpose: To force a scheduling message to be sent to the Calendar
User specified by the property.
Format Definition: This property parameter is defined by the
following notation:
scheduleforcesendparam = "SCHEDULE-FORCE-SEND" "="
("REQUEST" ; Force a "REQUEST"
/ "REPLY" ; Force a "REPLY"
/ iana-token) ; IANA registered method
Description: This property parameter MAY be specified on "ATTENDEE"
and "ORGANIZER" properties on which the "SCHEDULE-AGENT" property
parameter is set to the value "SERVER" or is not specified. This
property parameter is used to force a server to send a scheduling
message to a specific Calendar User in situations where the server
would not send a scheduling message otherwise (e.g., when no
change that warrants the delivery of a new scheduling message was
performed on the scheduling object resource). An Organizer MAY
specify this parameter on an "ATTENDEE" property with the value
"REQUEST" to force a "REQUEST" scheduling message to be sent to
this Attendee. An Attendee MAY specify this parameter on the
"ORGANIZER" with the value "REPLY" to force a "REPLY" scheduling
message to be sent to the Organizer.
Servers MUST NOT preserve this property parameter in scheduling
object resources, nor include it in any scheduling messages sent
as the result of an automatic scheduling transaction.
Clients SHOULD NOT include this parameter in any scheduling
messages that they themselves send.
Servers MUST set the "SCHEDULE-STATUS" parameter of the "ATTENDEE"
or "ORGANIZER" to 2.3 (i.e., "Success, invalid property parameter
ignored", see Section 3.6 of [I-D.ietf-calsify-2446bis]) when the
"SCHEDULE-FORCE-SEND" parameter is set to a x-name or iana-token
value they don't recognize.
Daboo & Desruisseaux Expires December 21, 2009 [Page 47]
Internet-Draft CalDAV Scheduling Extensions June 2009
Example:
ATTENDEE;SCHEDULE-FORCE-SEND=REQUEST:mailto:bernard@example.com
ORGANIZER;SCHEDULE-FORCE-SEND=REPLY:mailto:bernard@example.com
10.3. Schedule Status Parameter
Parameter Name: SCHEDULE-STATUS
Purpose: To specify the status codes returned from processing of the
most recent scheduling message sent to the corresponding Attendee,
or received from the corresponding Organizer.
Format Definition: This property parameter is defined by the
following notation:
schedulestatusparam = "SCHEDULE-STATUS" "="
( statcode
/ DQUOTE statcode *("," statcode) DQUOTE)
; "statcode" is defined in Section 3.8.8.3 of
; [I-D.ietf-calsify-rfc2445bis]. Value is a single
; "statcode" or a comma-separated list of "statcode" values.
Description: This property parameter MAY be specified on the
"ATTENDEE" and "ORGANIZER" properties.
Servers MUST add this property parameter to any "ATTENDEE"
properties corresponding to Calendar Users who were sent a
scheduling message via an automatic scheduling transaction.
Clients SHOULD NOT change or remove this parameter if it was
provided by the server. In the case where the client is handling
the scheduling, the client MAY add, change or remove this
parameter to indicate the last scheduling message status it
received.
Servers MUST add this parameter to any "ORGANIZER" properties
corresponding to Calendar Users who were sent a scheduling message
reply by an Attendee via an automatic scheduling transaction.
Clients SHOULD NOT change or remove this parameter if it was
provided by the server. In the case where the client is handling
the scheduling the client MAY add, change or remove this parameter
to indicate the last scheduling message status it received.
Servers MUST NOT include this parameter in any scheduling messages
sent as the result of an automatic scheduling transaction.
Daboo & Desruisseaux Expires December 21, 2009 [Page 48]
Internet-Draft CalDAV Scheduling Extensions June 2009
Clients SHOULD NOT include this parameter in any scheduling
messages that they themselves send.
Suitable values for this property parameter are described in
Section 9.2.
Example:
ATTENDEE;SCHEDULE-STATUS="2.0":mailto:bernard@example.com
ATTENDEE;SCHEDULE-STATUS="2.0,2.4":mailto:cyrus@example.com
Daboo & Desruisseaux Expires December 21, 2009 [Page 49]
Internet-Draft CalDAV Scheduling Extensions June 2009
11. Additional Message Header Fields
This specification defines additional HTTP request and response
headers for use with CalDAV.
11.1. Schedule-Reply Request Header
Schedule-Reply = "Schedule-Reply" ":" ("T" | "F")
Example:
Schedule-Reply: F
When an Attendee executes an HTTP DELETE request on a scheduling
object resource, and the Schedule-Reply header is not present, or
present and set to the value "T", the server MUST send an appropriate
reply scheduling message with the Attendee's "PARTSTAT" iCalendar
property parameter value set to "DECLINED" as part of its normal
automatic scheduling transaction processing.
When the Schedule-Reply header is set to the value "F", the server
MUST NOT send a scheduling message as part of its normal automatic
scheduling transaction processing.
The Schedule-Reply request header is used by a client to indicate to
a server whether or not an automatic scheduling transaction should
occur when an Attendee deletes a scheduling object resource. In
particular it controls whether a reply scheduling message is sent to
the Organizer as a result of the deletion. There are situations in
which unsolicited scheduling messages need to be silently deleted (or
ignored) for security or privacy reasons. This request header allows
the scheduling object resource to be deleted if such a need arises.
All scheduling object resources MUST support the Schedule-Reply
request header.
11.2. Schedule-Tag Response Header
The Schedule-Tag response header provides the current value of the
CALDAV:schedule-tag property value. The behavior of this response
header is described in Section 8.
All scheduling object resources MUST support the Schedule-Tag header.
Schedule-Tag = "Schedule-Tag" ":" opaque-tag
; "opaque-tag" is defined in Section 3.11 of [RFC2616]
Daboo & Desruisseaux Expires December 21, 2009 [Page 50]
Internet-Draft CalDAV Scheduling Extensions June 2009
Example:
Schedule-Tag: "12ab34-cd56ef"
11.3. If-Schedule-Tag-Match Request Header
The If-Schedule-Tag-Match request header field is used with a method
to make it conditional. Clients can set this header to the value
returned in the Schedule-Tag response header, or the CALDAV:schedule-
tag property, of a scheduling object resource previously retrieved
from the server to avoid overwriting "consequential" changes to the
scheduling object resource.
All scheduling object resources MUST support the If-Schedule-Tag-
Match header.
If-Schedule-Tag-Match = "If-Schedule-Tag-Match" ":" opaque-tag
; "opaque-tag" is defined in Section 3.11 of [RFC2616]
Example:
If-Schedule-Tag-Match: "12ab34-cd56ef"
Daboo & Desruisseaux Expires December 21, 2009 [Page 51]
Internet-Draft CalDAV Scheduling Extensions June 2009
12. Additional WebDAV Properties
The CalDAV scheduling extension defines the following new WebDAV
properties for use with CalDAV.
12.1. CALDAV:schedule-calendar-transp Property
Name: schedule-calendar-transp
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Determines whether the calendar object resources in a
calendar collection will affect the owner's freebusy.
Protected: This property MAY be protected and SHOULD NOT be returned
by a PROPFIND allprop request (as defined in Section 14.2 of
[RFC4918]).
COPY/MOVE behavior: This property value SHOULD be kept during a MOVE
operation, but is normally re-initialized when a resource is
created with a COPY. It should not be set in a COPY.
Description: This property SHOULD be defined on all calendar
collections. If present, it contains one of two XML elements that
indicate whether the calendar object resources in the calendar
collection should contribute to the owner's freebusy or not. When
the CALDAV:opaque element is used, all calendar object resources
in the corresponding calendar collection MUST contribute to
freebusy, assuming access privileges and other iCalendar
properties allow it to. When the CALDAV:transparent XML element
is used, the calendar object resources in the corresponding
calendar collection MUST NOT contribute to freebusy.
If this property is not present on a calendar collection, then the
default value CALDAV:opaque MUST be assumed.
Definition:
<!ELEMENT schedule-calendar-transp (opaque | transparent) >
<!ELEMENT opaque EMPTY>
<!-- Affect busy time searches -->
<!ELEMENT transparent EMPTY>
<!-- Invisible to busy time searches -->
Daboo & Desruisseaux Expires December 21, 2009 [Page 52]
Internet-Draft CalDAV Scheduling Extensions June 2009
Example:
<C:schedule-calendar-transp
xmlns:C="urn:ietf:params:xml:ns:caldav">
<C:opaque/>
</C:schedule-calendar-transp>
12.2. CALDAV:schedule-default-calendar-URL Property
Name: schedule-default-calendar-URL
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Specifies a default calendar for an Attendee where new
scheduling object resources are created.
Protected: This property MAY be protected in the case where a server
does not support changing the default calendar, or does not
support a default calendar.
COPY/MOVE behavior: This property is only defined on a scheduling
Inbox collection which cannot be moved or copied.
Description: This property MAY be defined on a scheduling Inbox
collection. If present, it contains zero or one DAV:href XML
elements. When a DAV:href element is present, its value indicates
a URL to a calendar collection that is used as the default
calendar. When no DAV:href element is present, it indicates that
there is no default calendar. In the absence of this property
there is no default calendar. When there is no default calendar
the server is free to choose the calendar in which a new
scheduling object resource is created. See Section 6.3.
Definition:
<!ELEMENT schedule-default-calendar-URL (DAV:href?) >
Example:
<C:schedule-default-calendar-URL xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:href>/home/cyrus/calendars/work/</D:href>
</C:schedule-default-calendar-URL>
Daboo & Desruisseaux Expires December 21, 2009 [Page 53]
Internet-Draft CalDAV Scheduling Extensions June 2009
12.3. CALDAV:schedule-tag Property
Name: schedule-tag
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Indicates whether a scheduling object resource has had a
"consequential" change made to it.
Value: opaque-tag (defined in Section 3.11 of [RFC2616])
Protected: This property MUST be protected as only the server can
update the value.
COPY/MOVE behavior: This property is only defined on scheduling
object resources. It MUST be preserved when a scheduling object
resource is copied or moved and the resulting resource is also a
scheduling object resource. If the source resource is not a
scheduling object resource but the destination resource is, this
property MUST be added to the destination resource.
Description: The CALDAV:schedule-tag property MUST be defined on all
scheduling object resources. This property is described in
Section 8.
Definition:
<!ELEMENT schedule-tag (#PCDATA) >
Example:
<C:schedule-tag xmlns:C="urn:ietf:params:xml:ns:caldav"
>"12345-67890"</C:schedule-tag>
Daboo & Desruisseaux Expires December 21, 2009 [Page 54]
Internet-Draft CalDAV Scheduling Extensions June 2009
13. Scheduling Access Control
13.1. Scheduling Privileges
CalDAV servers MUST support and adhere to the requirements of WebDAV
ACL [RFC3744]. Furthermore, CalDAV servers that advertise support
for the "calendar-auto-schedule" feature MUST also support the
scheduling privileges defined in this section.
All the scheduling privileges MUST be non-abstract and MUST appear in
the DAV:supported-privilege-set property of scheduling Outbox and
Inbox collections on which they are defined.
The tables specified in Appendix A clarify which scheduling methods
(e.g., "REQUEST", "REPLY", etc.) are controlled by each scheduling
privilege defined in this section.
13.1.1. Privileges on Scheduling Inbox Collections
This section defines new WebDAV ACL privileges that are for use on
scheduling Inbox collections. These privileges determine whether
delivery of scheduling messages from a calendar user is allowed by
the calendar user who "owns" the scheduling Inbox collection. This
allows calendar users to choose which other calendar users can
schedule with them.
Note that when a scheduling message is delivered to a calendar user,
in addition to a scheduling object resource being created in the
calendar user's scheduling Inbox collection, a new scheduling object
resource might be created or an existing one updated in a calendar
belonging to the calendar user. In that case, the ability to create
or update the scheduling object resource in the calendar is
controlled by the privileges assigned to the scheduling Inbox
collection.
The privileges defined in this section are ignored if applied to a
resource other than a scheduling Inbox collection.
13.1.1.1. CALDAV:schedule-deliver Privilege
CALDAV:schedule-deliver is an aggregate privilege that contains all
the scheduling privileges that control the processing and delivery of
incoming scheduling messages, that is, CALDAV:schedule-deliver-invite
and CALDAV:schedule-deliver-reply, as well as freebusy requests
targeted at the owner of the scheduling Inbox collection, that is,
CALDAV:schedule-query-freebusy.
<!ELEMENT schedule-deliver EMPTY >
Daboo & Desruisseaux Expires December 21, 2009 [Page 55]
Internet-Draft CalDAV Scheduling Extensions June 2009
13.1.1.2. CALDAV:schedule-deliver-invite Privilege
The CALDAV:schedule-deliver-invite privilege controls the processing
and delivery of scheduling messages coming from an Organizer.
<!ELEMENT schedule-deliver-invite EMPTY >
13.1.1.3. CALDAV:schedule-deliver-reply Privilege
The CALDAV:schedule-deliver-reply privilege controls the processing
and delivery of scheduling messages coming from an Attendee.
<!ELEMENT schedule-deliver-reply EMPTY >
13.1.1.4. CALDAV:schedule-query-freebusy Privilege
The CALDAV:schedule-query-freebusy privilege controls freebusy
requests targeted at the owner of the scheduling Inbox collection.
<!ELEMENT schedule-query-freebusy EMPTY >
13.1.2. Privileges on Scheduling Outbox Collections
This section defines new WebDAV ACL privileges that are defined for
use on scheduling Outbox collections. These privileges determine
which calendar users are allowed to send scheduling messages on
behalf of the calendar user who "owns" the scheduling Outbox
collection. This allows calendar users to choose other calendar
users who can act on their behalf to send schedule messages to other
calendar users (e.g. assistants working on behalf of their boss).
The privileges defined in this section are ignored if applied to a
resource other than a scheduling Outbox collection.
13.1.2.1. CALDAV:schedule-send Privilege
CALDAV:schedule-send is an aggregate privilege that contains all the
scheduling privileges that control the use of methods that will cause
scheduling messages to be delivered to other users, that is, CALDAV-
schedule-send-invite and CALDAV-schedule-send-reply, as well as
freebusy requests to be targeted at other users, that is, CALDAV-
schedule-send-freebusy.
<!ELEMENT schedule-send EMPTY >
Daboo & Desruisseaux Expires December 21, 2009 [Page 56]
Internet-Draft CalDAV Scheduling Extensions June 2009
13.1.2.2. CALDAV:schedule-send-invite Privilege
The CALDAV:schedule-send-invite privilege controls the sending of
scheduling messages by Organizers.
Users granted the DAV:bind privilege on a calendar collection, or
DAV:write privilege on scheduling object resources, will also need
the CALDAV:schedule-send-invite privilege granted on the scheduling
Outbox collection of the owner of the calendar collection or
scheduling object resource in order to be allowed to create, modify
or delete scheduling object resources in a way that will trigger the
CalDAV server to deliver organizer scheduling messages to other
calendar users.
<!ELEMENT schedule-send-invite EMPTY >
13.1.2.3. CALDAV:schedule-send-reply Privilege
The CALDAV:schedule-send-invite privilege controls the sending of
scheduling messages by Attendees.
Users granted the DAV:bind privilege on a calendar collection, or
DAV:write privilege on scheduling object resources, will also need
the CALDAV:schedule-send-reply privilege granted on the scheduling
Outbox collection of the owner of the calendar collection or
scheduling object resource in order to be allowed to create, modify
or delete scheduling object resources in a way that will trigger the
CalDAV server to deliver attendee scheduling messages to other
calendar users.
<!ELEMENT schedule-send-reply EMPTY >
13.1.2.4. CALDAV:schedule-send-freebusy Privilege
The CALDAV:schedule-send-freebusy privilege controls the use of the
POST method to submit scheduling messages that specify the scheduling
method "REQUEST" with a "VFREEBUSY" calendar component.
<!ELEMENT schedule-send-freebusy EMPTY >
13.1.3. Aggregation of Scheduling Privileges
Server implementations MUST aggregate the scheduling privileges as
follows:
DAV:all MUST contain CALDAV:schedule-send and CALDAV:schedule-
deliver;
Daboo & Desruisseaux Expires December 21, 2009 [Page 57]
Internet-Draft CalDAV Scheduling Extensions June 2009
CALDAV:schedule-send MUST contain CALDAV:schedule-send-invite,
CALDAV:schedule-send-reply, and CALDAV:schedule-send-freebusy;
CALDAV:schedule-deliver MUST contain CALDAV:schedule-deliver-
invite, CALDAV:schedule-deliver-reply, and CALDAV:schedule-query-
freebusy.
The following diagram illustrates how scheduling privileges are
aggregated according to the above requirements.
[DAV:all] (aggregate)
|
+-- [CALDAV:schedule-deliver] (aggregate)
| |
| +-- [CALDAV:schedule-deliver-invite]
| +-- [CALDAV:schedule-deliver-reply]
| +-- [CALDAV:schedule-query-freebusy]
|
+-- [CALDAV:schedule-send] (aggregate)
|
+-- [CALDAV:schedule-send-invite]
+-- [CALDAV:schedule-send-reply]
+-- [CALDAV:schedule-send-freebusy]
13.2. Additional Principal Properties
This section defines new properties for WebDAV principal resources as
defined in RFC3744 [RFC3744]. These properties are likely to be
protected but the server MAY allow them to be written by appropriate
users.
13.2.1. CALDAV:schedule-inbox-URL Property
Name: schedule-inbox-URL
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Identify the URL of the scheduling Inbox collection owned
by the associated principal resource.
Protected: This property MAY be protected.
PROPFIND behavior: This property SHOULD NOT be returned by a
PROPFIND allprop request (as defined in Section 14.2 of
[RFC4918]).
Daboo & Desruisseaux Expires December 21, 2009 [Page 58]
Internet-Draft CalDAV Scheduling Extensions June 2009
COPY/MOVE behavior: This property value SHOULD be preserved in COPY
and MOVE operations.
Description: This property is needed for a client to determine where
the scheduling Inbox collection of the current user is located so
that processing of scheduling messages can occur.
Definition:
<!ELEMENT schedule-inbox-URL (DAV:href)>
13.2.2. CALDAV:schedule-outbox-URL Property
Name: schedule-outbox-URL
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Identify the URL of the scheduling Outbox collection owned
by the associated principal resource.
Protected: This property MAY be protected.
PROPFIND behavior: This property SHOULD NOT be returned by a
PROPFIND allprop request (as defined in Section 14.2 of
[RFC4918]).
COPY/MOVE behavior: This property value SHOULD be preserved in COPY
and MOVE operations.
Description: This property is needed for a client to determine where
the scheduling Outbox collection of the current user is located so
that sending of scheduling messages can occur.
Definition:
<!ELEMENT schedule-outbox-URL DAV:href>
13.2.3. CALDAV:calendar-user-address-set Property
Name: calendar-user-address-set
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Identify the calendar addresses of the associated principal
resource.
Daboo & Desruisseaux Expires December 21, 2009 [Page 59]
Internet-Draft CalDAV Scheduling Extensions June 2009
Protected: This property MAY be protected.
PROPFIND behavior: This property SHOULD NOT be returned by a
PROPFIND allprop request (as defined in Section 14.2 of
[RFC4918]).
COPY/MOVE behavior: This property value SHOULD be preserved in COPY
and MOVE operations.
Description: Support for this property is REQUIRED. This property
is needed to map calendar user addresses in iCalendar data to
principal resources and their associated scheduling Inbox and
Outbox collections. In the event that a user has no well defined
identifier for their calendar user address, the URI of their
principal resource can be used. This property SHOULD be
searchable using the DAV:principal-property-search REPORT. The
DAV:principal-search-property-set REPORT SHOULD identify this
property as such.
Definition:
<!ELEMENT calendar-user-address-set (DAV:href*)>
Example:
<C:calendar-user-address-set xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:href>mailto:bernard@example.com</D:href>
<D:href>mailto:bernard.desruisseaux@example.com</D:href>
</C:calendar-user-address-set>
13.2.4. CALDAV:calendar-user-type Property
Name: calendar-user-type
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Identifies the calendar user type of the associated
principal resource.
Value: Same values allowed for the iCalendar "CUTYPE" property
parameter defined in Section 3.2.3 of
[I-D.ietf-calsify-rfc2445bis].
Protected: This property MAY be protected.
Daboo & Desruisseaux Expires December 21, 2009 [Page 60]
Internet-Draft CalDAV Scheduling Extensions June 2009
PROPFIND behavior: This property SHOULD NOT be returned by a
PROPFIND allprop request (as defined in Section 14.2 of
[RFC4918]).
COPY/MOVE behavior: This property value SHOULD be preserved in COPY
and MOVE operations.
Description: This property MAY be defined on principal resources to
indicate the type of calendar user associated with this principal
resource. Its value is the same as the iCalendar "CUTYPE"
property parameter that can be used on "ATTENDEE" properties.
This property SHOULD be searchable using the DAV:principal-
property-search REPORT. The DAV:principal-search-property-set
REPORT SHOULD identify this property as such.
Definition:
<!ELEMENT calendar-user-type (#PCDATA) >
Example:
<C:calendar-user-type
xmlns:C="urn:ietf:params:xml:ns:caldav">INDIVIDUAL<
/C:calendar-user-type>
Daboo & Desruisseaux Expires December 21, 2009 [Page 61]
Internet-Draft CalDAV Scheduling Extensions June 2009
14. XML Element Definitions
14.1. CALDAV:schedule-response XML Element
Name: schedule-response
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Contains the set of responses for a POST method request.
Description: See Section 7.3.
Definition:
<!ELEMENT schedule-response (response*)>
14.2. CALDAV:response XML Element
Name: response
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Contains a single response for a POST method request.
Description: See Section 7.3.
Definition:
<!ELEMENT response (recipient,
request-status,
calendar-data?,
DAV:error?,
DAV:responsedescription?)>
14.3. CALDAV:recipient XML Element
Name: recipient
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: The calendar user address that the enclosing response for a
POST method request is for.
Description: See Section 7.3.
Daboo & Desruisseaux Expires December 21, 2009 [Page 62]
Internet-Draft CalDAV Scheduling Extensions June 2009
Definition:
<!ELEMENT recipient (DAV:href)>
14.4. CALDAV:request-status XML Element
Name: request-status
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: The iTIP "REQUEST-STATUS" property value for this response.
Description: See Section 7.3.
Definition:
<!ELEMENT request-status (#PCDATA) >
Daboo & Desruisseaux Expires December 21, 2009 [Page 63]
Internet-Draft CalDAV Scheduling Extensions June 2009
15. Security Considerations
The process of scheduling involves the sending and receiving of
scheduling messages. As a result, the security problems related to
messaging in general are relevant here. In particular the
authenticity of the scheduling messages needs to be verified.
Servers and clients MUST use an HTTP connection protected with TLS as
defined in [RFC2818] for all scheduling transactions.
15.1. Verifying Scheduling Transactions
When handling a scheduling transaction:
Servers MUST verify that the principal associated with the DAV:
owner of the calendar collection in which a scheduling object
resource is being manipulated contains a CALDAV:schedule-outbox-
URL property value.
Servers MUST verify that the currently authenticated user has the
CALDAV:schedule-send privilege, or a suitable sub-privilege
aggregated under this privilege, on the scheduling Outbox
collection of the DAV:owner of the calendar collection in which a
scheduling object resource is being manipulated.
Servers MUST only deliver scheduling messages to recipients when
the CALDAV:schedule-deliver privilege, or a suitable sub-privilege
aggregated under this privilege, is granted on the recipient's
scheduling Inbox collection for the principal associated with the
DAV:owner of the calendar collection in which a scheduling object
resource is being manipulated.
To prevent impersonation of calendar users, the server MUST verify
that the "ORGANIZER" property in an organizer scheduling object
resource matches one of the calendar user addresses of the DAV:
owner of the calendar collection in which the resource is stored.
To prevent spoofing of an existing scheduling object resource,
servers MUST verify that the "UID" iCalendar property value in a
new scheduling object resource does not match that of an existing
scheduling object resource with a different "ORGANIZER" property
value.
15.2. Verifying Busy Time Information Requests
When handling a POST request on a scheduling Outbox collection:
Daboo & Desruisseaux Expires December 21, 2009 [Page 64]
Internet-Draft CalDAV Scheduling Extensions June 2009
Servers MUST verify that the principal associated with the
calendar user address specified in the "ORGANIZER" property of the
scheduling message data in the request contains a CALDAV:schedule-
outbox-URL property value that matches the scheduling Outbox
collection targeted by the request.
Servers MUST verify that the currently authenticated user has the
CALDAV:schedule-send privilege, or a sub-privilege aggregated
under this privilege, on the scheduling Outbox collection targeted
by the request.
Servers MUST only return valid freebusy information for recipients
when the CALDAV:schedule-deliver privilege, or a sub-privilege
aggregated under this privilege, is granted on the recipient's
scheduling Inbox collection for the principal associated with the
DAV:owner of the scheduling Outbox collection targeted by the
request.
15.3. Privacy Issues
As noted in Section 11.1, Attendees can use the Schedule-Reply
request header with the value set to "F" to prevent notification to
an Organizer that a scheduling object resource was deleted. This
allows Attendees to remove unwanted scheduling messages without any
response to the Organizer.
Daboo & Desruisseaux Expires December 21, 2009 [Page 65]
Internet-Draft CalDAV Scheduling Extensions June 2009
16. IANA Considerations
16.1. Message Header Field Registrations
The message header fields below should be added to the Permanent
Message Header Field Registry (see [RFC3864]).
16.1.1. Schedule-Reply
Header field name: Schedule-Reply
Applicable protocol: http
Status: standard
Author/Change controller: IETF
Specification document(s): this specification (Section 11.1)
Related information: none
16.1.2. Schedule-Tag
Header field name: Schedule-Tag
Applicable protocol: http
Status: standard
Author/Change controller: IETF
Specification document(s): this specification (Section 11.2)
Related information: none
16.1.3. If-Schedule-Tag-Match
Header field name: If-Schedule-Tag-Match
Applicable protocol: http
Status: standard
Author/Change controller: IETF
Specification document(s): this specification (Section 11.3)
Related information: none
Daboo & Desruisseaux Expires December 21, 2009 [Page 66]
Internet-Draft CalDAV Scheduling Extensions June 2009
16.2. iCalendar Property Parameter Registrations
The following iCalendar property parameters should be added to the
iCalendar Property Parameter Registry defined in Section 8.3.3 of
[I-D.ietf-calsify-rfc2445bis].
+---------------------+---------+-----------------------+
| Parameter | Status | Reference |
+---------------------+---------+-----------------------+
| SCHEDULE-AGENT | Current | RFCXXXX, Section 10.1 |
| | | |
| SCHEDULE-STATUS | Current | RFCXXXX, Section 10.3 |
| | | |
| SCHEDULE-FORCE-SEND | Current | RFCXXXX, Section 10.2 |
+---------------------+---------+-----------------------+
16.3. Additional iCalendar Elements Registries
The IANA should create and maintain the following additional
registries for iCalendar elements with pointers to appropriate
reference documents.
16.3.1. Schedule Agent Values Registry
The following table should be used to initialize the schedule agent
values registry.
+----------------+---------+------------------------+
| Schedule Agent | Status | Reference |
+----------------+---------+------------------------+
| SERVER | Current | RFC XXXX, Section 10.1 |
| | | |
| CLIENT | Current | RFC XXXX, Section 10.1 |
| | | |
| NONE | Current | RFC XXXX, Section 10.1 |
+----------------+---------+------------------------+
16.3.2. Schedule Force Send Values Registry
The following table should be used to initialize the schedule send
values registry.
+---------------------+---------+------------------------+
| Schedule Force Send | Status | Reference |
+---------------------+---------+------------------------+
| REQUEST | Current | RFC XXXX, Section 10.2 |
| | | |
Daboo & Desruisseaux Expires December 21, 2009 [Page 67]
Internet-Draft CalDAV Scheduling Extensions June 2009
| REPLY | Current | RFC XXXX, Section 10.2 |
+---------------------+---------+------------------------+
Daboo & Desruisseaux Expires December 21, 2009 [Page 68]
Internet-Draft CalDAV Scheduling Extensions June 2009
17. Acknowledgements
The authors would like to thank the following individuals for
contributing their ideas and support for writing this specification:
Mike Douglass, Lisa Dusseault, Helge Hess, Arnaud Quillaud, Julian F.
Reschke, Wilfredo Sanchez Vega, Simon Vaillancourt, and Jim
Whitehead.
The authors would also like to thank the Calendaring and Scheduling
Consortium for advice with this specification, and for organizing
interoperability testing events to help refine it.
Daboo & Desruisseaux Expires December 21, 2009 [Page 69]
Internet-Draft CalDAV Scheduling Extensions June 2009
18. References
18.1. Normative References
[I-D.ietf-calsify-2446bis] Daboo, C., "iCalendar Transport-
Independent Interoperability Protocol
(iTIP)", draft-ietf-calsify-2446bis-09
(work in progress), April 2009.
[I-D.ietf-calsify-rfc2445bis] Desruisseaux, B., "Internet
Calendaring and Scheduling Core Object
Specification (iCalendar)",
draft-ietf-calsify-rfc2445bis-10 (work
in progress), April 2009.
[RFC2119] Bradner, S., "Key words for use in
RFCs to Indicate Requirement Levels",
BCP 14, RFC 2119, March 1997.
[RFC2616] Fielding, R., Gettys, J., Mogul, J.,
Frystyk, H., Masinter, L., Leach, P.,
and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1",
RFC 2616, June 1999.
[RFC2818] Rescorla, E., "HTTP Over TLS",
RFC 2818, May 2000.
[RFC3744] Clemm, G., Reschke, J., Sedlar, E.,
and J. Whitehead, "Web Distributed
Authoring and Versioning (WebDAV)
Access Control Protocol", RFC 3744,
May 2004.
[RFC3864] Klyne, G., Nottingham, M., and J.
Mogul, "Registration Procedures for
Message Header Fields", BCP 90,
RFC 3864, September 2004.
[RFC4791] Daboo, C., Desruisseaux, B., and L.
Dusseault, "Calendaring Extensions to
WebDAV (CalDAV)", RFC 4791,
March 2007.
[RFC4918] Dusseault, L., "HTTP Extensions for
Web Distributed Authoring and
Versioning (WebDAV)", RFC 4918,
June 2007.
Daboo & Desruisseaux Expires December 21, 2009 [Page 70]
Internet-Draft CalDAV Scheduling Extensions June 2009
[RFC5234] Crocker, D. and P. Overell, "Augmented
BNF for Syntax Specifications: ABNF",
STD 68, RFC 5234, January 2008.
[W3C.REC-xml-20081126] Maler, E., Yergeau, F., Sperberg-
McQueen, C., Paoli, J., and T. Bray,
"Extensible Markup Language (XML) 1.0
(Fifth Edition)", World Wide Web
Consortium Recommendation REC-xml-
20081126, November 2008, <http://
www.w3.org/TR/2008/REC-xml-20081126>.
18.2. Informative References
[I-D.ietf-calsify-rfc2447bis] Melnikov, A., "iCalendar Message-Based
Interoperability Protocol (iMIP)",
draft-ietf-calsify-rfc2447bis-05 (work
in progress), June 2008.
[RFC3283] Mahoney, B., Babics, G., and A. Taler,
"Guide to Internet Calendaring",
RFC 3283, June 2002.
Daboo & Desruisseaux Expires December 21, 2009 [Page 71]
Internet-Draft CalDAV Scheduling Extensions June 2009
Appendix A. Scheduling Privileges Summary
A.1. Scheduling Inbox Privileges
The following tables specify which scheduling privileges grant the
right to a calendar user to deliver a scheduling message to the
scheduling Inbox collection of another calendar user. The
appropriate behavior depends on the calendar component type as well
as the scheduling "METHOD" specified in the scheduling message.
+--------------------------------+
| METHOD for VEVENT and VTODO |
+-----------------------------+---------+-------+-----+--------+
| Scheduling Inbox Privilege | REQUEST | REPLY | ADD | CANCEL |
+-----------------------------+---------+-------+-----+--------+
| schedule-deliver | * | * | * | * |
| schedule-deliver-invite | * | | * | * |
| schedule-deliver-reply | | * | | |
| schedule-query-freebusy | | | | |
+-----------------------------+---------+-------+-----+--------+
+----------------------+
| METHOD for VFREEBUSY |
+-----------------------------+----------------------+
| Scheduling Inbox Privilege | REQUEST |
+-----------------------------+----------------------+
| schedule-deliver | * |
| schedule-deliver-invite | |
| schedule-deliver-reply | |
| schedule-query-freebusy | * |
+-----------------------------+----------------------+
A.2. Scheduling Outbox Privileges
The following tables specify which scheduling privileges grant the
right to a Calendar User to perform busy time information requests
and to submit scheduling messages to other Calendar Users as the
result of a scheduling transaction. The appropriate behavior depends
on the calendar component type as well as the scheduling "METHOD"
specified in the scheduling message.
Daboo & Desruisseaux Expires December 21, 2009 [Page 72]
Internet-Draft CalDAV Scheduling Extensions June 2009
+--------------------------------+
| METHOD for VEVENT and VTODO |
+-----------------------------+---------+-------+-----+--------+
| Scheduling Outbox Privilege | REQUEST | REPLY | ADD | CANCEL |
+-----------------------------+---------+-------+-----+--------+
| schedule-send | * | * | * | * |
| schedule-send-invite | * | | * | * |
| schedule-send-reply | | * | | |
| schedule-send-freebusy | | | | |
+-----------------------------+---------+-------+-----+--------+
+----------------------+
| METHOD for VFREEBUSY |
+-----------------------------+----------------------+
| Scheduling Outbox Privilege | REQUEST |
+-----------------------------+----------------------+
| schedule-send | * |
| schedule-send-invite | |
| schedule-send-reply | |
| schedule-send-freebusy | * |
+-----------------------------+----------------------+
Daboo & Desruisseaux Expires December 21, 2009 [Page 73]
Internet-Draft CalDAV Scheduling Extensions June 2009
Appendix B. Example Scheduling Transactions
This section describes some example scheduling transactions that give
a general idea of how scheduling is carried out between CalDAV
clients and servers from the perspective of meeting Organizers and
Attendees.
In the following examples the requests and responses are incomplete
and are only for illustrative purposes. In particular, HTTP
authentication headers and behaviors are not shown, even though they
are required in normal operation.
B.1. Example: Organizer Inviting Multiple Attendees
In the following example, Cyrus invites Wilfredo, Bernard and Mike to
a single instance event by simply creating a new scheduling object
resource in one of his calendar collection by using the PUT method.
Daboo & Desruisseaux Expires December 21, 2009 [Page 74]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Request <<
PUT /home/cyrus/calendars/work/9263504FD3AD.ics HTTP/1.1
Host: cal.example.com
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090602T185254Z
DTSTART:20090602T160000Z
DTEND:20090602T170000Z
TRANSP:OPAQUE
SUMMARY:Lunch
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega";CUTYPE=INDIVIDUAL;PARTSTAT
=NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:wilfredo@
example.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:bernard@ex
ample.net
ATTENDEE;CN="Mike Douglass";CUTYPE=INDIVIDUAL;PARTSTAT=NEEDS-A
CTION;RSVP=TRUE:mailto:mike@example.org
END:VEVENT
END:VCALENDAR
>> Response <<
HTTP/1.1 201 Created
Content-Length: 0
Date: Tue, 02 Jun 2009 18:52:54 GMT
Last-Modified: Tue, 02 Jun 2009 18:52:54 GMT
ETag: "d85561cfe74a4e785eb4639451b434fb"
Schedule-Tag: "488177c8-2ea7-4176-a6cb-fab8cfccdea2"
Once the event creation has been completed, Cyrus's client will
retrieve the event back from the server to get the schedule status of
each Attendee. In this example, the server reports that a scheduling
message was delivered to Wilfredo, a scheduling message is still
pending for Bernard, and the server was unable to deliver a
scheduling message to Mike.
Daboo & Desruisseaux Expires December 21, 2009 [Page 75]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Request <<
GET /home/cyrus/calendars/work/9263504FD3AD.ics HTTP/1.1
>> Response <<
HTTP/1.1 200 OK
Date: Tue, 02 Jun 2009 18:52:58 GMT
Last-Modified: Tue, 02 Jun 2009 18:52:58 GMT
ETag: "eb897deabc8939589da116714bc99265"
Schedule-Tag: "488177c8-2ea7-4176-a6cb-fab8cfccdea2"
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Server//EN
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090602T185300Z
DTSTART:20090602T160000Z
DTEND:20090602T170000Z
TRANSP:OPAQUE
SUMMARY:Lunch
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega";CUTYPE=INDIVIDUAL;PARTSTAT
=NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE;SCHEDULE-STATUS=
"1.2;Scheduling message has been delivered":mailto:wilfredo@e
xample.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE;SCHEDULE-STATUS="
1.0;Scheduling message is pending":mailto:bernard@example.net
ATTENDEE;CN="Mike Douglass";CUTYPE=INDIVIDUAL;PARTSTAT=NEEDS-A
CTION;RSVP=TRUE;SCHEDULE-STATUS="3.7;Invalid calendar user":m
ailto:mike@example.org
END:VEVENT
END:VCALENDAR
B.2. Example: Attendee Receiving an Invitation
In the following example, Wilfredo's client retrieves and deletes the
new scheduling message that appeared in his scheduling Inbox
collection after the server automatically processed it and created a
new scheduling object resource in his default calendar collection.
Daboo & Desruisseaux Expires December 21, 2009 [Page 76]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Request <<
GET /home/wilfredo/calendars/inbox/27d93fc0a58c.ics HTTP/1.1
Host: cal.example.com
>> Response <<
HTTP/1.1 200 OK
Date: Tue, 02 Jun 2009 18:59:58 GMT
Last-Modified: Tue, 02 Jun 2009 18:59:58 GMT
ETag: "da116714bc9926c89395895eb897deab"
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Server//EN
METHOD:REQUEST
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090602T185254Z
DTSTART:20090602T160000Z
DTEND:20090602T170000Z
TRANSP:OPAQUE
SUMMARY:Lunch
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega";CUTYPE=INDIVIDUAL;PARTSTAT
=NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:wilfredo@
example.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:bernard@ex
ample.net
ATTENDEE;CN="Mike Douglass";CUTYPE=INDIVIDUAL;PARTSTAT=NEEDS-A
CTION;RSVP=TRUE:mailto:mike@example.org
END:VEVENT
END:VCALENDAR
>> Request <<
DELETE /home/wilfredo/calendars/inbox/27d93fc0a58c.ics HTTP/1.1
Host: cal.example.com
Daboo & Desruisseaux Expires December 21, 2009 [Page 77]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Response <<
HTTP/1.1 204 No Content
Date: Tue, 02 Jun 2009 20:40:36 GMT
B.3. Example: Attendee Replying to an Invitation
In the following example, Wilfredo's accepts Cyrus's invitation and
sets a reminder on the event.
>> Request <<
PUT /home/wilfredo/calendars/work/BB64861C2228.ics HTTP/1.1
Host: cal.example.com
If-Schedule-Tag-Match: "e78f23ed-0188-4bab-938d-2aeb3324c7e8"
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090602T185254Z
DTSTART:20090602T160000Z
DTEND:20090602T170000Z
TRANSP:OPAQUE
SUMMARY:Lunch
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega";CUTYPE=INDIVIDUAL;PARTSTAT
=ACCEPTED;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:wilfredo@exam
ple.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:bernard@ex
ample.net
ATTENDEE;CN="Mike Douglass";CUTYPE=INDIVIDUAL;PARTSTAT=NEEDS-A
CTION;RSVP=TRUE:mailto:mike@example.org
BEGIN:VALARM
TRIGGER:-PT15M
ACTION:DISPLAY
DESCRIPTION:Reminder
END:VALARM
END:VEVENT
END:VCALENDAR
Daboo & Desruisseaux Expires December 21, 2009 [Page 78]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Response <<
HTTP/1.1 200 OK
Content-Length: 0
Date: Tue, 02 Jun 2009 18:57:54 GMT
Last-Modified: Tue, 02 Jun 2009 18:57:54 GMT
ETag: "eb4639451b434fbd85561cfe74a4e785"
Schedule-Tag: "8893ee45-eb9d-428f-b53c-c777daf19e41"
Once the event modification has been completed, Wilfredo's client
will retrieve the event back from the server to get the schedule
status of the Organizer.
>> Request <<
PUT /home/wilfredo/calendars/work/BB64861C2228.ics HTTP/1.1
Host: cal.example.com
Daboo & Desruisseaux Expires December 21, 2009 [Page 79]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Response <<
HTTP/1.1 200 OK
Date: Tue, 02 Jun 2009 19:03:03 GMT
Last-Modified: Tue, 02 Jun 2009 19:02:21 GMT
ETag: "5eb897deabda116714bc9926c8939589"
Schedule-Tag: "8893ee45-eb9d-428f-b53c-c777daf19e41"
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090602T190221Z
DTSTART:20090602T160000Z
DTEND:20090602T170000Z
TRANSP:OPAQUE
SUMMARY:Lunch
ORGANIZER;CN="Cyrus Daboo";SCHEDULE-STATUS="1.2;Scheduling mes
sage has been delivered":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega";CUTYPE=INDIVIDUAL;PARTSTAT
=ACCEPTED;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:wilfredo@exam
ple.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:bernard@ex
ample.net
ATTENDEE;CN="Mike Douglass";CUTYPE=INDIVIDUAL;PARTSTAT=NEEDS-A
CTION;RSVP=TRUE:mailto:mike@example.org
BEGIN:VALARM
TRIGGER:-PT15M
ACTION:DISPLAY
DESCRIPTION:Reminder
END:VALARM
END:VEVENT
END:VCALENDAR
B.4. Example: Organizer Receiving a Reply to an Invitation
On reception of Wilfredo's reply, Cyrus's server will automatically
update Cyrus's scheduling object resource, make Wilfredo's scheduling
message available in Cyrus's scheduling Inbox collection, and deliver
an updated scheduling message to Bernard to share Wilfredo's updated
participation status. In this example, Cyrus's client retrieves and
Daboo & Desruisseaux Expires December 21, 2009 [Page 80]
Internet-Draft CalDAV Scheduling Extensions June 2009
deletes this scheduling message in his scheduling Inbox collection.
>> Request <<
GET /home/cyrus/calendars/inbox/c0a58c27d93f.ics HTTP/1.1
>> Response <<
HTTP/1.1 200 OK
Date: Tue, 02 Jun 2009 19:05:02 GMT
Last-Modified: Tue, 02 Jun 2009 19:04:20 GMT
ETag: "9265eb897deabc8939589da116714bc9"
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Server//EN
METHOD:REPLY
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090602T185754Z
DTSTART:20090602T160000Z
DTEND:20090602T170000Z
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega";PARTSTAT=ACCEPTED:mailto:w
ilfredo@example.com
REQUEST-STATUS:2.0;Success
END:VEVENT
END:VCALENDAR
>> Request <<
DELETE /home/cyrus/calendars/inbox/c0a58c27d93f.ics HTTP/1.1
Host: cal.example.com
>> Response <<
HTTP/1.1 204 No Content
Date: Tue, 02 Jun 2009 19:05:05 GMT
Cyrus's client then retrieves the event back from the server with
Wilfredo's updated participation status.
Daboo & Desruisseaux Expires December 21, 2009 [Page 81]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Request <<
GET /home/cyrus/calendars/work/9263504FD3AD.ics HTTP/1.1
Host: cal.example.com
>> Response <<
HTTP/1.1 200 OK
Date: Tue, 02 Jun 2009 19:05:02 GMT
Last-Modified: Tue, 02 Jun 2009 19:04:20 GMT
ETag: "eb897deabc8939589da116714bc99265"
Schedule-Tag: "132cab27-1fe3-67ab-de13-abd348d1dee3"
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Server//EN
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090602T190420Z
DTSTART:20090602T160000Z
DTEND:20090602T170000Z
TRANSP:OPAQUE
SUMMARY:Lunch
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega";CUTYPE=INDIVIDUAL;PARTSTAT
=ACCEPTED;ROLE=REQ-PARTICIPANT;RSVP=TRUE;SCHEDULE-STATUS="2.0
;Reply has been received":mailto:wilfredo@example.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE;SCHEDULE-STATUS="
1.0;Scheduling message is pending":mailto:bernard@example.net
ATTENDEE;CN="Mike Douglass";CUTYPE=INDIVIDUAL;PARTSTAT=NEEDS-A
CTION;RSVP=TRUE;SCHEDULE-STATUS="3.7;Invalid calendar user":m
ailto:mike@example.org
END:VEVENT
END:VCALENDAR
B.5. Example: Organizer Requesting Busy Time Information
In this example, Cyrus requests the busy time information of Wilfredo
and Bernard.
Daboo & Desruisseaux Expires December 21, 2009 [Page 82]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Request <<
POST /home/cyrus/calendars/outbox/ HTTP/1.1
Host: cal.example.com
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
METHOD:REQUEST
BEGIN:VFREEBUSY
UID:4FD3AD926350
DTSTAMP:20090602T190420Z
DTSTART:20090602T000000Z
DTEND:20090604T000000Z
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega":mailto:wilfredo@example.com
ATTENDEE;CN="Bernard Desruisseaux":mailto:bernard@example.net
END:VFREEBUSY
END:VCALENDAR
>> Response <<
HTTP/1.1 200 OK
Date: Tue, 02 Jun 2009 20:07:34 GMT
Content-Type: application/xml; charset="utf-8"
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?>
<C:schedule-response xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<C:response>
<C:recipient>
<D:href>mailto:wilfredo@example.com<D:href>
</C:recipient>
<C:request-status>2.0;Success</C:request-status>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Server//EN
METHOD:REPLY
BEGIN:VFREEBUSY
UID:4FD3AD926350
DTSTAMP:20090602T200733Z
DTSTART:20090602T000000Z
DTEND:20090604T000000Z
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega":mailto:wilfredo@example.com
Daboo & Desruisseaux Expires December 21, 2009 [Page 83]
Internet-Draft CalDAV Scheduling Extensions June 2009
FREEBUSY;FBTYPE=BUSY:20090602T110000Z/20090602T120000Z
FREEBUSY;FBTYPE=BUSY:20090603T170000Z/20090603T180000Z
END:VFREEBUSY
END:VCALENDAR
</C:calendar-data>
</C:response>
<C:response>
<C:recipient>
<D:href>mailto:bernard@example.net<D:href>
</C:recipient>
<C:request-status>2.0;Success</C:request-status>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Server//EN
METHOD:REPLY
BEGIN:VFREEBUSY
UID:4FD3AD926350
DTSTAMP:20090602T200733Z
DTSTART:20090602T000000Z
DTEND:20090604T000000Z
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Bernard Desruisseaux":mailto:bernard@example.net
FREEBUSY;FBTYPE=BUSY:20090602T150000Z/20090602T160000Z
FREEBUSY;FBTYPE=BUSY:20090603T090000Z/20090603T100000Z
FREEBUSY;FBTYPE=BUSY:20090603T180000Z/20090603T190000Z
END:VFREEBUSY
END:VCALENDAR
</C:calendar-data>
</C:response>
</C:schedule-response>
B.6. Example: User Attempting to Invite Attendee on behalf of Organizer
In the following example, Cyrus attempts to create, on behalf of
Wilfredo, an event with Bernard specified as an Attendee. The
request fails since Wilfredo didn't grant Cyrus the right to invite
other Calendar Users on his behalf.
Daboo & Desruisseaux Expires December 21, 2009 [Page 84]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Request <<
PUT /home/wilfredo/calendars/work/def456.ics HTTP/1.1
Host: cal.example.com
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
UID:3504F926D3AD
SEQUENCE:0
DTSTAMP:20090602T190221Z
DTSTART:20090602T230000Z
DTEND:20090603T000000Z
TRANSP:OPAQUE
SUMMARY:Dinner
ORGANIZER;CN="Wilfredo Sanchez Vega":mailto:wilfredo@example.com
ATTENDEE;CN="Wilfredo Sanchez Vega";CUTYPE=INDIVIDUAL;PARTSTAT=A
CCEPTED:mailto:wilfredo@example.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=NE
EDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:bernard@exampl
e.net
END:VEVENT
END:VCALENDAR
>> Response <<
HTTP/1.1 403 Forbidden
Content-Type: application/xml; charset="utf-8"
Content-Length: xxxx
<D:error xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:need-privileges>
<D:resource>
<D:href>/home/wilfredo/calendars/outbox/</D:href>
<D:privilege><C:schedule-send-invite/></D:privilege>
</D:resource>
</D:need-privileges>
</D:error>
B.7. Example: Attendee Declining an Instance of a Recurring Event
In the following example, Bernard declines the second recurrence
instance of a daily recurring event he's been invited to by Cyrus.
>> Request <<
Daboo & Desruisseaux Expires December 21, 2009 [Page 85]
Internet-Draft CalDAV Scheduling Extensions June 2009
PUT /home/bernard/calendars/work/4FD3AD926350.ics HTTP/1.1
Host: cal.example.com
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VTIMEZONE
TZID:America/Montreal
BEGIN:STANDARD
DTSTART:20071104T020000
RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
TZNAME:EST
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:20070311T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
TZNAME:EDT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090602T185254Z
DTSTART;TZID=America/Montreal:20090601T150000
DTEND;TZID=America/Montreal:20090601T160000
RRULE:FREQ=DAILY;INTERVAL=1;COUNT=5
TRANSP:OPAQUE
SUMMARY:Review Internet-Draft
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
ACCEPTED;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:bernard@exampl
e.net
END:VEVENT
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090603T183823Z
RECURRENCE-ID;TZID=America/Montreal:20090602T150000
DTSTART;TZID=America/Montreal:20090602T150000
DTEND;TZID=America/Montreal:20090602T160000
Daboo & Desruisseaux Expires December 21, 2009 [Page 86]
Internet-Draft CalDAV Scheduling Extensions June 2009
TRANSP:TRANSPARENT
SUMMARY:Review Internet-Draft
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
DECLINED;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:bernard@exampl
e.net
END:VEVENT
END:VCALENDAR
>> Response <<
HTTP/1.1 200 OK
Content-Length: 0
Date: Tue, 02 Jun 2009 18:52:54 GMT
Last-Modified: Tue, 02 Jun 2009 18:52:54 GMT
ETag: "d85561cfe74a4e785eb4639451b434fb"
Schedule-Tag: "488177c8-2ea7-4176-a6cb-fab8cfccdea2"
Bernard's participation status update will cause his server to
deliver a scheduling message to Cyrus. Cyrus's client will find the
following reply message from Bernard in Cyrus's scheduling Inbox
collection:
>> Request <<
GET /home/cyrus/calendars/inbox/9263504FD3AD.ics HTTP/1.1
Daboo & Desruisseaux Expires December 21, 2009 [Page 87]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Response <<
HTTP/1.1 200 OK
Date: Tue, 02 Jun 2009 18:52:58 GMT
Last-Modified: Tue, 02 Jun 2009 18:52:58 GMT
ETag: "eb897deabc8939589da116714bc99265"
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
METHOD:REPLY
BEGIN:VTIMEZONE
TZID:America/Montreal
BEGIN:STANDARD
DTSTART:20071104T020000
RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
TZNAME:EST
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:20070311T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
TZNAME:EDT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090603T183823Z
RECURRENCE-ID;TZID=America/Montreal:20090602T150000
DTSTART;TZID=America/Montreal:20090602T150000
DTEND;TZID=America/Montreal:20090602T160000
SUMMARY:Review Internet-Draft
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Bernard Desruisseaux";PARTSTAT=DECLINED:
mailto:bernard@example.net
REQUEST-STATUS:2.0;Success
END:VEVENT
END:VCALENDAR
Daboo & Desruisseaux Expires December 21, 2009 [Page 88]
Internet-Draft CalDAV Scheduling Extensions June 2009
B.8. Example: Attendee Removing an Instance of a Recurring Event
In the following example, Bernard removes from his calendar the third
recurrence instance of a daily recurring event he's been invited to
by Cyrus. This is accomplished by the addition of an "EXDATE"
property to the scheduling object resource stored by Bernard.
>> Request <<
PUT /home/bernard/calendars/work/4FD3AD926350.ics HTTP/1.1
Host: cal.example.com
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VTIMEZONE
TZID:America/Montreal
BEGIN:STANDARD
DTSTART:20071104T020000
RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
TZNAME:EST
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:20070311T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
TZNAME:EDT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090602T185254Z
DTSTART;TZID=America/Montreal:20090601T150000
DTEND;TZID=America/Montreal:20090601T160000
RRULE:FREQ=DAILY;INTERVAL=1;COUNT=5
EXDATE;TZID=America/Montreal:20090603T150000
TRANSP:OPAQUE
SUMMARY:Review Internet-Draft
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
Daboo & Desruisseaux Expires December 21, 2009 [Page 89]
Internet-Draft CalDAV Scheduling Extensions June 2009
ACCEPTED;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:bernard@exampl
e.net
END:VEVENT
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090603T183823Z
RECURRENCE-ID;TZID=America/Montreal:20090602T150000
DTSTART;TZID=America/Montreal:20090602T150000
DTEND;TZID=America/Montreal:20090602T160000
TRANSP:TRANSPARENT
SUMMARY:Review Internet-Draft
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Cyrus Daboo";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:
mailto:cyrus@example.com
ATTENDEE;CN="Bernard Desruisseaux";CUTYPE=INDIVIDUAL;PARTSTAT=
DECLINED;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:bernard@exampl
e.net
END:VEVENT
END:VCALENDAR
Bernard's deletion of a recurrence instance will cause his server to
deliver a scheduling message to Cyrus. Cyrus's client will find the
following reply message from Bernard in Cyrus's scheduling Inbox
collection:
>> Request <<
GET /home/cyrus/calendars/inbox/6504923FD3AD.ics HTTP/1.1
Daboo & Desruisseaux Expires December 21, 2009 [Page 90]
Internet-Draft CalDAV Scheduling Extensions June 2009
>> Response <<
HTTP/1.1 200 OK
Date: Tue, 02 Jun 2009 18:52:58 GMT
Last-Modified: Tue, 02 Jun 2009 18:52:58 GMT
ETag: "eb897deabc8939589da116714bc99265"
Content-Type: text/calendar; charset="utf-8"
Content-Length: xxxx
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
METHOD:REPLY
BEGIN:VTIMEZONE
TZID:America/Montreal
BEGIN:STANDARD
DTSTART:20071104T020000
RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
TZNAME:EST
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:20070311T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
TZNAME:EDT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
UID:9263504FD3AD
SEQUENCE:0
DTSTAMP:20090603T183823Z
RECURRENCE-ID;TZID=America/Montreal:20090603T150000
DTSTART;TZID=America/Montreal:20090603T150000
DTEND;TZID=America/Montreal:20090603T160000
SUMMARY:Review Internet-Draft
ORGANIZER;CN="Cyrus Daboo":mailto:cyrus@example.com
ATTENDEE;CN="Bernard Desruisseaux";PARTSTAT=DECLINED:
mailto:bernard@example.net
REQUEST-STATUS:2.0;Success
END:VEVENT
END:VCALENDAR
Daboo & Desruisseaux Expires December 21, 2009 [Page 91]
Internet-Draft CalDAV Scheduling Extensions June 2009
Appendix C. Changes (to be removed by RFC Editor prior to publication)
C.1. Changes in -07
a. Restructured document.
b. Clarified that CALDAV:schedule-calendar-transp only applies to
calendar collection.
c. Removed CALDAV:schedule-state property on scheduling messages in
the scheduling Inbox collection.
d. Added conditional requests on scheduling object resources.
e. Added section on handling of PARTSTAT.
f. Added SCHEDULE-FORCE-SEND iCalendar property parameter.
g. Added clarification on child resources in scheduling Outbox
collections.
h. Clarified Attendee changes that server MUST allow, and removed
restrictions on changes that Attendee MUST NOT do.
i. Added Example Scheduling Transactions appendix.
j. Scheduling privileges are no longer required to be non-abstract.
k. Removed handling of REFRESH requests.
l. Removed handling of VJOURNAL components.
m. Completed IANA Considerations section.
n. Added references to RFC3283 and RFC5234.
o. Updated references to iCalendar, iTIP and iMIP.
C.2. Changes in -06
a. Removed distinction between scheduling calendar collections and
basic calendar collections - now just have calendar collections.
b. Clients now "MAY" reload data rather than "SHOULD" reload data.
c. Fixed <C:recipient> in examples.
Daboo & Desruisseaux Expires December 21, 2009 [Page 92]
Internet-Draft CalDAV Scheduling Extensions June 2009
d. Removed CALDAV:attachments-allowed precondition on POST to Outbox
as that is no longer relevant.
e. Added CALDAV:default-calendar-delete-allowed precondition for
DELETE.
f. Relaxed MUST->MAY for Organizer setting PARTSTAT value.
g. Tweaked restrictions on Create/Modify to emphasize that 4791
restrictions also apply.
h. Added comment that 'opaque' is the default when the CALDAV:
schedule-calendar-transp property is not present.
i. Description of Schedule-Reply header changed to reflect that it
is only relevant for Attendees.
j. Minor typos fixed.
C.3. Changes in -05
This draft has changed substantially since the -04 version. The
primary reason for this change was implementation experience from a
number of vendors who implemented products based on the earlier
drafts. Experience showed that the client/server interaction was not
reliable in keeping scheduling messages synchronized between
organizer and attendees. In addition the latency in updates due to
clients being offline proved unacceptable to users. These issues led
to the redesign of this specification to support a server-based
processing model that eliminates all the problems seen previously.
Whilst this adds significant complexity to the server in that it
needs to be a full blown iTIP processing agent, it does remove a lot
of the same complexity from clients, opening up the possibility of
supporting complex scheduling behaviors even with "thin" clients.
In the judgement of the authors, we consider this new specification
to be a substantial improvement over the old one and believe it
represents a stronger protocol that will lead to better
interoperability.
Daboo & Desruisseaux Expires December 21, 2009 [Page 93]
Internet-Draft CalDAV Scheduling Extensions June 2009
Authors' Addresses
Cyrus Daboo
Apple Inc.
1 Infinite Loop
Cupertino, CA 95014
USA
EMail: cyrus@daboo.name
URI: http://www.apple.com/
Bernard Desruisseaux
Oracle Corporation
600 Blvd. de Maisonneuve West
Suite 1900
Montreal, QC H3A 3J2
CANADA
EMail: bernard.desruisseaux@oracle.com
URI: http://www.oracle.com/
Daboo & Desruisseaux Expires December 21, 2009 [Page 94]
