WDIFF

draft-dusseault-caldav-08.txt --> draft-dusseault-caldav-09.txt

Network Working Group C. Daboo
Internet-Draft ISAMET
Expires: April 3, June 26, 2006 B. Desruisseaux
Oracle
L. Dusseault
OSAF
September 30,
December 23, 2005

Calendaring Extensions to WebDAV (CalDAV)
draft-dusseault-caldav-08
draft-dusseault-caldav-09

Status of this Memo

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This Internet-Draft will expire on April 3, June 26, 2006.

Abstract

This document specifies a set of methods, headers, message bodies,
properties, and reports that define calendar access extensions to the
WebDAV protocol. The new protocol elements are intended to make
WebDAV-based calendaring and scheduling an interoperable standard
that supports calendar access, calendar management, calendar sharing,

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and calendar publishing.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 5
1.2. XML Namespaces . . . . . . . . . . . . . . . . . . . . . . 5
1.3. Method Preconditions and Postconditions . . . . . . . . . 6
2. CalDAV Requirements Overview . . . . . . . . . . . . . . . . . 7
3. Capability Discovery . . . 6
3. Calendaring Data Model . . . . . . . . . . . . . . . . . . . 8 . 7
3.1. CalDAV Calendar Server Support . . . . . . . . . . . . . . . . . . 8
3.1.1. Example: Using OPTIONS for the Discovery of
Support for CalDAV . . . . 7
3.2. Recurrence and the Data Model . . . . . . . . . . . . . . 8
4. Calendar Resources . . . . . . . . . . . . . . . . . . . . . . 9
4.1. Calendaring Data Model . . Calendar Object Resources . . . . . . . . . . . . . . . . 9
4.1.1.
4.2. Calendar Server Collection . . . . . . . . . . . . . . . . . . . 9
4.1.2. Recurrence and the Data Model 10
5. Calendar Access Feature . . . . . . . . . . . . 10
4.2. Calendar Collection . . . . . . . 11
5.1. Calendar Access Support . . . . . . . . . . . . 10
4.3. Calendaring Properties . . . . . 11
5.1.1. Example: Using OPTIONS for the Discovery of
Calendar Access Support . . . . . . . . . . . . . . . 11
4.3.1. CALDAV:calendar-description Property
5.2. Calendar Collection Properties . . . . . . . . . 11
4.3.2. CALDAV:calendar-component-restriction-set Property . . 12
4.3.3. CALDAV:calendar-restrictions Property . . . 12
5.2.1. CALDAV:calendar-description Property . . . . . 13
4.4. Calendar Object Resource Restrictions in Calendar
Collections . . . . 12
5.2.2. CALDAV:calendar-timezone Property . . . . . . . . . . 12
5.2.3. CALDAV:supported-calendar-component-set Property . . . 14
5.2.4. CALDAV:supported-calendar-data Property . . . . . . . 13
4.5. 15
5.3. Creating Resources . . . . . . . . . . . . . . . . . . . . 15
4.5.1.
5.3.1. MKCALENDAR Method . . . . . . . . . . . . . . . . . . 15
4.5.1.1. 16
5.3.1.1. Status Codes . . . . . . . . . . . . . . . . . . . 16
4.5.1.2. Example - 17
5.3.1.2. Example: Successful MKCALENDAR request . . . . . . 18
5.3.2. Creating Calendar Object Resources . . . . . . . . . . 17
4.5.2. Creating 20
5.3.3. Calendar Object Resources . Resource Entity Tag . . . . . . . . . 18
5. 22
6. Calendaring Access Control . . . . . . . . . . . . . . . . . . 21
5.1. 23
6.1. Calendaring Privileges Privilege . . . . . . . . . . . . . . . . . . 21
5.1.1. 23
6.1.1. CALDAV:read-free-busy Privilege . . . . . . . . . . . 21
5.1.2. Privilege aggregation and the
DAV:supported-privilege-set property 23
6.2. Additional Principal Property . . . . . . . . . 21
5.1.2.1. Partial example of DAV:supported-privilege-set
property . . . . . 23
6.2.1. CALDAV:calendar-home-set Property . . . . . . . . . . 23
7. Calendaring Reports . . . . . . 22
5.2. Additional Principal Properties . . . . . . . . . . . . . 23
5.2.1. CALDAV:calendar-home-set Property . . 24
7.1. REPORT Method . . . . . . . . . . . 23
6. Calendaring Reports . . . . . . . . . . . 24
7.2. Ordinary collections . . . . . . . . . . 24
6.1. REPORT Method . . . . . . . . . 25
7.3. Date and floating time . . . . . . . . . . . . . 24
6.2. Reports on non-calendar collections . . . . . 25
7.4. Time range filtering . . . . . . 24
6.3. Reports and recurring items . . . . . . . . . . . . . 26
7.5. Returned calendar components . . 24
6.4. . . . . . . . . . . . . . 26
7.6. CALDAV:calendar-query Report . . . . . . . . . . . . . . . 25
6.4.1. 27
7.6.1. Example: Partial retrieval of events by time range . . 26
6.4.2. 28
7.6.2. Example: Partial retrieval of recurring events . . . . 29
6.4.3. 31
7.6.3. Example: Expanded retrieval of recurring events . . . 32
6.4.4. 35
7.6.4. Example: Retrieval Partial retrieval of to-dos by alarm time range stored free busy
components . . . 35

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6.4.5.

7.6.5. Example: Retrieval of event to-dos by UID . . . . . . . alarm time range . . . 36
6.4.6. 40
7.6.6. Example: Retrieval of events event by participation
status . . . . . . . UID . . . . . . . . . . 40
7.6.7. Example: Retrieval of events by PARTSTAT . . . . . . . 37
6.4.7. 41
7.6.8. Example: Retrieval of events only . . . . . . . . . . 38
6.5. 42
7.7. CALDAV:calendar-multiget Report . . . . . . . . . . . . . 39
6.5.1. 43
7.7.1. Example: Successful CALDAV:calendar-multiget Report . . . . . . . 40
6.6. 44
7.8. CALDAV:free-busy-query Report . . . . . . . . . . . . . . 42
6.6.1. 45
7.8.1. Example: Successful CALDAV:free-busy-query Report . . . . . . . . 44
7. 47
8. Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7.1. 48
8.1. Client-to-client Interoperability . . . . . . . . . . . . 46
7.2. Sychronization 48
8.2. Synchronization Operations . . . . . . . . . . . . . . . . 46
7.2.1. 48
8.2.1. Use of Reports . . . . . . . . . . . . . . . . . . . . 46
7.2.1.1. 49
8.2.1.1. Restrict the Time Range . . . . . . . . . . . . . 46
7.2.1.2. 49
8.2.1.2. Synchronize by Time Range . . . . . . . . . . . . 46
7.2.1.3. 49
8.2.1.3. Synchronization Process . . . . . . . . . . . . . 47
7.2.2. 49
8.2.2. Restrict the Properties Returned . . . . . . . . . . . 49
7.3. 51
8.3. Use of Locking . . . . . . . . . . . . . . . . . . . . . . 50
7.4. 51
8.4. Finding calendars . . . . . . . . . . . . . . . . . . . . 50
7.5. 52
8.5. Storing and Using Attachments . . . . . . . . . . . . . . 51
7.5.1. 53
8.5.1. Inline attachments . . . . . . . . . . . . . . . . . . 51
7.5.2. 54
8.5.2. External attachments . . . . . . . . . . . . . . . . . 51
7.6. 54
8.6. Storing and Using Alarms . . . . . . . . . . . . . . . . . 52
8. 55
9. XML Element Definitions . . . . . . . . . . . . . . . . . . . 54
8.1. 56
9.1. CALDAV:calendar XML Element . . . . . . . . . . . . . . . 56
9.2. CALDAV:mkcalendar XML Element . . . . . . . . . . . . . . 57
9.3. CALDAV:mkcalendar-response XML Element . . . . . . . . . . 57
9.4. CALDAV:calendar-query XML Element . . . . . . . . . . . . 54
8.2. 57
9.5. CALDAV:calendar-data XML Element . . . . . . . . . . . . . 54
8.2.1. 58
9.5.1. CALDAV:comp XML Element . . . . . . . . . . . . . . . 54
8.2.2. 59
9.5.2. CALDAV:allcomp XML Element . . . . . . . . . . . . . . 55
8.2.3. 59
9.5.3. CALDAV:allprop XML Element . . . . . . . . . . . . . . 55
8.2.4. 60
9.5.4. CALDAV:prop XML Element . . . . . . . . . . . . . . . 56
8.2.5. CALDAV:expand-recurrence-set 60
9.5.5. CALDAV:expand XML Element . . . . . . . 56
8.2.6. . . . . . . . 61
9.5.6. CALDAV:limit-recurrence-set XML Element . . . . . . . 57
8.3. 61
9.5.7. CALDAV:limit-freebusy-set XML Element . . . . . . . . 62
9.6. CALDAV:filter XML Element . . . . . . . . . . . . . . . . 57
8.3.1. 63
9.6.1. CALDAV:comp-filter XML Element . . . . . . . . . . . . 58
8.3.2. 63
9.6.2. CALDAV:prop-filter XML Element . . . . . . . . . . . . 58
8.3.3. 64
9.6.3. CALDAV:param-filter XML Element . . . . . . . . . . . 59
8.3.4. CALDAV:is-defined 64
9.6.4. CALDAV:text-match XML Element . . . . . . . . . . . . 59
8.3.5. CALDAV:text-match 65
9.7. CALDAV:timezone XML Element . . . . . . . . . . . . 59
8.4. . . . 65
9.8. CALDAV:time-range XML Element . . . . . . . . . . . . . . 60
8.5. 66
9.9. CALDAV:calendar-multiget XML Element . . . . . . . . . . . 61
8.6. 67
9.10. CALDAV:free-busy-query XML Element . . . . . . . . . . . . 61
9. 68
10. Internationalization Considerations . . . . . . . . . . . . . 63
10. 68
11. Security Considerations . . . . . . . . . . . . . . . . . . . 64
11. 68
12. IANA Consideration . . . . . . . . . . . . . . . . . . . . . . 65
11.1. 69
12.1. Namespace Registration . . . . . . . . . . . . . . . . . . 65
12. Acknowledgements . . . . . . . . . . 69

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13. Acknowledgements . . . . . . . . . . . . . 66
13. . . . . . . . . . . 69
14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 67
13.1. 70
14.1. Normative References . . . . . . . . . . . . . . . . . . . 67
13.2. 70
14.2. Informative References . . . . . . . . . . . . . . . . . . 68

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Appendix A. CalDAV Method Privilege Table (Normative) . . . . . . 69 71
Appendix B. Calendar collections used in the examples . . . . . . 71
Appendix C. Changes . . . . . . . . . . . . . . . . . . . . . . . 70
B.1. 71
C.1. Changes in -09 . . . . . . . . . . . . . . . . . . . . . . 72
C.2. Changes in -08 . . . . . . . . . . . . . . . . . . . . . . 70
B.2. 73
C.3. Changes in -07 . . . . . . . . . . . . . . . . . . . . . . 70
B.3. 74
C.4. Changes in -06 . . . . . . . . . . . . . . . . . . . . . . 71
B.4. 75
C.5. Changes in -05 . . . . . . . . . . . . . . . . . . . . . . 72
B.5. 75
C.6. Changes in -04 . . . . . . . . . . . . . . . . . . . . . . 72
B.6. 76
C.7. Changes in -03 . . . . . . . . . . . . . . . . . . . . . . 73
B.7. 76
C.8. Changes in -02 . . . . . . . . . . . . . . . . . . . . . . 73
B.8. 77
C.9. Changes in -01 . . . . . . . . . . . . . . . . . . . . . . 73 77
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 74 78
Intellectual Property and Copyright Statements . . . . . . . . . . 75 79

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1. Introduction

The concept of using HTTP [5] [RFC2616] and WebDAV [4] [RFC2518] as a basis
for a
calendaring server calendar access protocol is by no means a new concept: it was
discussed in the IETF CALSCH working group as early as 1997 or 1998.
Several companies have implemented calendaring servers calendar access protocols using
HTTP PUT/GET to upload and download iCalendar [3] [RFC2445] objects, and using
WebDAV PROPFIND to get listings of resources. However, those implementations
do not interoperate because there are many small and big decisions to
be made in how to model calendaring data as WebDAV resources, as well
as how to implement required features that aren't already part of
WebDAV. This document proposes a standard way of modeling to model calendar data in
WebDAV, with additional features to make an interoperable calendar
access work
well. protocol.

Discussion of this Internet-Draft is taking place on the mailing list
<http://lists.osafoundation.org/mailman/listinfo/ietf-caldav>.

1.1. Notational Conventions

The augmented BNF used by this document to describe protocol elements
is described in Section 2.1 of [5]. Because this augmented BNF uses
the basic production rules provided in Section 2.2 of [5], those
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 [1]. [RFC2119].

The term "protected" is used in the Conformance field of property
definitions as defined in Section 1.4.2 of RFC3253 [7]. [RFC3253].

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 type names respectively.

1.2. XML Namespaces

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 [10]. [W3C.REC-xml-20040204].

The namespace "urn:ietf:params:xml:ns:caldav" is reserved for the XML
elements defined in this specification, its revisions, and related
CalDAV specifications. It XML elements defined by individual
implementations MUST NOT be used for proprietary
extensions.

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Note that use the "urn:ietf:params:xml:ns:caldav"
namespace, and instead should use a namespace that they control.

The XML declarations used in this document are incomplete,
in that they do not include namespace
information. Thus, the reader 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

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defined by WebDAV [RFC2518] which use the "DAV:" namespace. Wherever
such XML elements appear, they are explicitly given the prefixed with "DAV:" prefix to help
avoid confusion.

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.

1.3. Method Preconditions and Postconditions

A "precondition" of a method describes the state of the server that
must be true for that method to be performed. A "postcondition" of a
method describes the state of the server that must be true after that
method has been completed. If a method precondition or postcondition
for a request is not satisfied, the response status of the request
MUST be either 403 (Forbidden) if the request should not be repeated
because it will always fail, or 409 (Conflict) if it is expected that
the user might be able to resolve the conflict and resubmit the
request.

In order to allow better client handling of 403 and 409 responses, a
distinct XML element type is associated with each method precondition
and postcondition of a request. When a particular precondition is
not satisfied or a particular postcondition cannot be achieved, the
appropriate XML element MUST be returned as the child of a top-level
DAV:error element in the response body, unless otherwise negotiated
by the request. In a 207 Multi-Status response, the DAV:error
element would appear in the appropriate DAV:responsedescription
element.

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2. CalDAV Requirements Overview

This section lists what functionality is required of a CalDAV server.
To advertise support for CalDAV, a server:

o MUST support iCalendar [RFC2445] as a media type for calendar
object resource format;

o MUST support WebDAV Class 1 [4]. [RFC2518];

o MUST support WebDAV ACL [9] [RFC3744] with the additional privilege
defined in Section 5.1 6.1 of this document. document;

o MUST support transport over TLS [2] [RFC2246] as defined in RFC2818 [6]. [RFC2818];

o MUST support strong ETags to support disconnected operations.

o MUST support all required [RFC2616] with additional requirements
specified in Section 5.3.3 of this document;

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o MUST support all calendaring REPORTs defined in Section 7 of this
document.
document; and

o MUST advertise support on all calendar collections and calendar
object resources for the calendaring REPORTs via in the DAV:supported-report-
set DAV:supported-
report-set property as defined in Versioning Extensions to WebDAV [7].
[RFC3253].

In addition, a server:

o SHOULD support the MKCALENDAR method defined in Section 4.5.1 5.3.1 of
this document.

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3. Capability Discovery

3.1. CalDAV Server Support

If a server supports the CalDAV features described in this document,
it MUST include "calendar-access" as a field in the DAV response
header from an OPTIONS request on any resource that supports any
calendar properties, reports, methods, or privilege. A value of
"calendar-access" in the DAV header MUST indicate that the server
supports all MUST level requirements and REQUIRED features specified
in this document.

3.1.1. Example: Using OPTIONS for the Discovery of Support for CalDAV

>> Request <<

OPTIONS /home/bernard/calendars/ HTTP/1.1
Host: cal.example.com

>> Response <<

HTTP/1.1 200 OK
Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE
Allow: PROPFIND, PROPPATCH, LOCK, UNLOCK, REPORT, ACL
DAV: 1, 2, access-control, calendar-access
Content-Length: 0

In this example, the OPTIONS method returns the value "calendar-
access" in the DAV header of the response to indicate that the
"/home/bernard/calendars/" collection may support properties,
reports, methods, or privilege defined in this specification.

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4. Calendar Resources

4.1. Calendaring Data Model

One of the features which has made WebDAV a successful protocol is
its firm data model. This makes it a useful framework for other
applications such as calendaring. This specification follows the
same pattern by developing all features based on a well-described
data model.

In the

As a brief overview, a CalDAV data model, every VEVENT, VTODO, VJOURNAL, VTIMEZONE
and VFREEBUSY component calendar is contained in an individual resource,
referred to modelled as a "calendar object resource". Each calendar object WebDAV
collection with defined structure; each calendar collection contains
a number of resources representing calendar objects as its direct
child resource. Each resource may representing a calendar object (event
or to-do, or journal entry, or other calendar components) is called a
"calendar object resource". Each calendar object resource and each
calendar collection can be individually locked and have individual
WebDAV properties. These resources Requirements derived from this model are placed into WebDAV collections with
a mostly-fixed structure.

4.1.1. provided
in Section 4.1 and Section 4.2.

3.1. Calendar Server

A CalDAV server is a calendaring-aware engine combined with a WebDAV
repository. A WebDAV repository is a set of WebDAV collections,
containing other WebDAV resources, within a unified URL namespace.
For example, the repository "http://www.example.com/webdav/" may
contain WebDAV collections and resources, all of which have URLs
beginning with "http://www.example.com/webdav/". Note that the root
URL "http://www.example.com/" may not itself be a WebDAV repository
(for example, if the WebDAV support is implemented through a servlet
or other Web server extension).

A WebDAV repository MAY include calendar data in some parts of its
URL namespace, and non-calendaring data in other parts.

A WebDAV repository can advertise itself as a CalDAV server if it

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supports the functionality defined in this specification at any point
within the root of the repository. That might mean that calendaring
data is spread throughout the repository and mixed with non-calendar
data in nearby collections (e.g., calendar data may be found in
/home/lisa/calendars/ as well as in /home/bernard/calendars/, and
non-calendar data in /home/lisa/contacts/). Or, it might mean that
calendar data can be found only in certain sections of the repository
(e.g., /calendar/). Calendaring features are only required in the
repository sections that are or contain calendar object resources.
So a repository confining calendar data to the /calendar/ collection
would only need to support the CalDAV required features within that
collection.

The CalDAV server or repository is the canonical location for
calendar data and state information. Both CalDAV servers and clients

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MUST ensure that the data is consistent and compliant. Clients may
submit requests to change data or download data. Clients may store
calendar objects offline and attempt to synchronize at a later time.
However, clients MUST be prepared for calendar data on the server to
change between the time of last synchronization and when attempting
an update, as calendar collections may be shared and accessible via
multiple clients. HTTP ETags Entity tags and other features help make this work.

4.1.2. possible.

3.2. Recurrence and the Data Model

Recurrence is an important part of the data model because it governs
how many resources are expected to exist. This specification models
a recurring calendar component and its recurrence exceptions as a
single resource. In this model, recurrence patterns, rules, recurrence dates,
exception dates, rules, and exception information dates are all part of the data in a
single calendar object resource. This model avoids problems of
limiting how many recurrence instances to store in the repository,
how to keep recurrence instances in synch sync with the recurring calendar
component, and how to link recurrence exceptions with the recurring
calendar component. It also results in less data to synchronize
between client and server, and makes it easier to make changes to all
recurrence instances or to a recurrence pattern. rule. It makes it easier to
create a recurring calendar component, and easier to delete all
recurrence instances.

Clients are not forced to retrieve information about all recurrence
instances of a recurring component. The CALDAV:calendar-query and
CALDAV:calendar-multiget REPORTs defined in this document allow
clients to retrieve only recurrence instances that overlap a given
time range.

4.2.

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4. Calendar Collection Resources

4.1. Calendar Object Resources

Calendar object resources contained in calendar collections are manifested to clients as a WebDAV resource
collection, identified by a URL. A MUST NOT
contain more than one type of calendar collection component (e.g., VEVENT,
VTODO, VJOURNAL, VFREEBUSY, etc.) with the exception of VTIMEZONE
components which MUST report be specified for each unique TZID parameter
value specified in the DAV:collection iCalendar object. For instance, a calendar
object resource can contain two VEVENT components and CALDAV:calendar XML elements one VTIMEZONE
component, but it cannot contain one VEVENT component and one VTODO
component.

Calendar object resources contained in calendar collections MUST NOT
specify the iCalendar METHOD property.

The UID property value of the DAV:resourcetype property. The element type declaration for
CALDAV:calendar is:

<!ELEMENT calendar EMPTY>

A calendar collection contains components contained in a
calendar object resources that
represent iCalendar objects within resource MUST be unique in the scope of the calendar
collection.

Calendar components in a calendar. A calendar collection
may be created through provisioning (e.g., automatically created when that have different UID
property values MUST be stored in separate calendar object resources.

Calendar components with the same UID property value, in a user's account is created), or it may given
calendar collection, MUST be created through MKCALENDAR
(see Section 4.5.1). contained in the same calendar object
resource. This can be useful for a user to create ensures that all components in a
second recurrence "set" are
contained in the same calendar (e.g., soccer schedule) or for users to share object resource. In that case there
will be one component without a
calendar (e.g., team events or conference room). Note however RECURRENCE-ID property (the component
that defines the recurrence pattern) and all the rest will have that
property (these are the recurrence exceptions).

For example, given the following iCalendar object:

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this document doesn't define what extra calendar collections are for,
users must rely on non-standard cues to find out what a calendar
collection is for, or use

BEGIN:VCALENDAR
PRODID:-//Example Corp.//CalDAV Client//EN
VERSION:2.0
BEGIN:VEVENT
UID:1@example.com
SUMMARY:One-off Meeting
DTSTAMP:20041210T183904Z
DTSTART:20041207T120000Z
DTEND:20041207T130000Z
END:VEVENT
BEGIN:VEVENT
UID:2@example.com
SUMMARY:Weekly Meeting
DTSTAMP:20041210T183838Z
DTSTART:20041206T120000Z
DTEND:20041206T130000Z
RRULE:FREQ=WEEKLY
END:VEVENT
BEGIN:VEVENT
UID:2@example.com
SUMMARY:Weekly Meeting
RECURRENCE-ID:20041213T120000Z
DTSTAMP:20041210T183838Z
DTSTART:20041213T130000Z
DTEND:20041213T140000Z
END:VEVENT
END:VCALENDAR

The VEVENT component with the CALDAV:calendar-description property
defined UID value "1@example.com", would be
stored in Section 4.3.1 to provide such its own calendar object resource. The two VEVENT
components with the UID value "2@example.com", which represent a cue.
recurring event where one recurrence instance has been overridden,
would be stored in the same calendar object resource.

4.2. Calendar collections MUST only contain Collection

A calendar collection contains calendar object resources and
collections that
represent calendar components within a calendar. A calendar
collection is manifested to clients as a WebDAV resource collection
identified by a URL. A calendar collection MUST report the DAV:
collection and CALDAV:calendar XML elements in the value of the DAV:
resourcetype property. The element type declaration for CALDAV:
calendar is:

<!ELEMENT calendar EMPTY>

A calendar collection can be created through provisioning (e.g.,
automatically created when a user's account is provisioned), or it

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can be created with the MKCALENDAR method (see Section 5.3.1). This
method can be useful for a user to create a second calendar (e.g.,
soccer schedule) or for users to share a calendar (e.g., team events
or conference room). Note however that this document doesn't define
what extra calendar collections are for. Users must rely on non-
standard cues to find out what a calendar collection is for, or use
the CALDAV:calendar-description property defined in Section 5.2.1 to
provide such a cue.

Calendar collections MUST only contain calendar object resources and
collections that are not calendar collections. Furthermore,
collections contained in calendar collections MUST NOT contain
calendar collections. This specification does not define how
collections contained in calendar collections are used and may relate
to the calendar object resources contained in the calendar
collections.

Multiple calendar collections MAY be children of the same collection.

4.3. Calendaring Properties

This section defines properties that may be defined on calendar
collections.

4.3.1. CALDAV:calendar-description Property

Name: calendar-description

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Provides a human-readable description of what

5. Calendar Access Feature

5.1. Calendar Access Support

A server supporting the features described in this calendar
collection represents.

Conformance: This property MAY be protected and SHOULD NOT be
returned by document MUST
include "calendar-access" as a PROPFIND allprop request (as defined field in Section
12.14.1 of [4]). An xml:lang attribute indicating the human
language of the description SHOULD be set for this property DAV response header from
an OPTIONS request on any resource that supports any calendar
properties, reports, method, or privilege. A value of "calendar-
access" in the DAV response header MUST indicate that the server
supports all MUST level requirements specified in this document.

5.1.1. Example: Using OPTIONS for the Discovery of Calendar Access
Support

>> Request <<

OPTIONS /home/bernard/calendars/ HTTP/1.1
Host: cal.example.com

>> Response <<

HTTP/1.1 200 OK
Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE
Allow: PROPFIND, PROPPATCH, LOCK, UNLOCK, REPORT, ACL
DAV: 1, 2, access-control, calendar-access
Date: Fri, 11 Nov 2005 09:32:12 GMT
Content-Length: 0

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In this example, the OPTIONS method returns the value "calendar-
access" in the DAV response header to indicate that the collection
"/home/bernard/calendars/" may support properties, reports, methods,
or privilege defined in this specification.

5.2. Calendar Collection Properties

This section defines properties that MAY be defined on calendar
collections.

5.2.1. CALDAV:calendar-description Property

Name: calendar-description

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Provides a human-readable description of the calendar
collection.

Conformance: This property MAY be protected and SHOULD NOT be
returned by a PROPFIND allprop request (as defined in Section
12.14.1 of [RFC2518]). An xml:lang attribute indicating the human
language of the description SHOULD be set for this property by
clients or through server provisioning. Servers MUST return any
xml:lang attribute if set for the property.

Description: The CALDAV:calendar-description property MAY be defined
on any calendar collection. If present, the property contains a
description of the calendar collection that is suitable for
presentation to a user.

Definition:

<!ELEMENT calendar-description (#PCDATA) > (#PCDATA)>
PCDATA value: string

Example:

<C:calendar-description xml:lang="fr-CA"
xmlns:C="urn:ietf:params:xml:ns:caldav"
>Calendrier de Mathilde Desruisseaux</C:calendar-description>

5.2.2. CALDAV:calendar-timezone Property

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Example:

<C:calendar-description xml:lang="fr-CA"
xmlns:C="urn:ietf:params:xml:ns:caldav"
>Calendrier de Bernard Desruisseaux</C:calendar-description>

4.3.2. CALDAV:calendar-component-restriction-set Property

Name: calendar-component-restriction-set calendar-timezone

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies the type of calendar component types (e.g.,
VEVENT, VTODO, etc.) that calendar object resources may contain in a time zone on a calendar collection.

Conformance: This property MUST SHOULD NOT be returned by a PROPFIND
allprop request (as defined in Section 12.14.1 of [RFC2518]).

Description: The CALDAV:calendar-timezone property SHOULD be defined
on all calendar collections to specify the time zone the server
should rely on to resolve "date" values and "date with local time"
values (i.e., floating time) to "date with UTC time" values. The
server will require this information to determine if a calendar
component scheduled with "date" values or "date with local time"
values overlaps a CALDAV:time-range specified in a CALDAV:
calendar-query REPORT. The server will also require this
information to compute the proper FREEBUSY time period as "date
with UTC time" in the VFREEBUSY component returned in a response
to a CALDAV:free-busy-query REPORT request that takes into account
calendar components scheduled with "date" values or "date with
local time" values.

Definition:

<!ELEMENT calendar-timezone (#PCDATA)>
PCDATA value: an iCalendar object with exactly one VTIMEZONE
component.

Example:

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<C:calendar-timezone
xmlns:C="urn:ietf:params:xml:ns:caldav">BEGIN:VCALENDAR
PRODID:-//Example Corp.//CalDAV Client//EN
VERSION:2.0
BEGIN:VTIMEZONE
TZID:US-Eastern
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:Eastern Standard Time (US &amp; Canada)
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:Eastern Daylight Time (US &amp; Canada)
END:DAYLIGHT
END:VTIMEZONE
END:VCALENDAR
</C:calendar-timezone>

5.2.3. CALDAV:supported-calendar-component-set Property

Name: supported-calendar-component-set

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies the type of calendar component types (e.g.,
VEVENT, VTODO, etc.) that calendar object resources may contain in
the calendar collection.

Conformance: This property MUST be protected and SHOULD NOT be
returned by a PROPFIND allprop request (as defined in Section
12.14.1 of [4]). [RFC2518]).

Description: The CALDAV:calendar-component-restriction-set CALDAV:supported-calendar-component-set property MAY
be defined on any calendar collection to specify restrictions on
the calendar component types that calendar object resources may
contain in a calendar collection. Since this property is
protected it cannot be changed by clients using a PROPPATCH
request. However, clients can initialize the value of this
property when creating a new calendar collection with MKCALENDAR.
The element empty-element tag <C:comp name="VTIMEZONE"> name="VTIMEZONE"/> MUST only be
specified if support for calendar object resources that only contains

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contain VTIMEZONE components is provided or desired. Support for
VTIMEZONE components in calendar object resources that contain
VEVENT or VTODO components is always assumed.

Definition:

<!ELEMENT calendar-component-restriction-set supported-calendar-component-set (comp*)>

Example:

<C:calendar-component-restriction-set

<C:supported-calendar-component-set
xmlns:C="urn:ietf:params:xml:ns:caldav">
<C:comp name="VEVENT"/>
<C:comp name="VTODO"/>
</C:calendar-component-restriction-set>

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4.3.3. CALDAV:calendar-restrictions
</C:supported-calendar-component-set>

5.2.4. CALDAV:supported-calendar-data Property

Name: calendar-restrictions supported-calendar-data

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies restrictions on a calendar collection.

Conformance: This property MUST be protected and SHOULD NOT be
returned by a PROPFIND allprop request (as defined in Section
12.14.1 of [4]). [RFC2518]).

Description: The CALDAV:calendar-restrictions CALDAV:supported-calendar-data property MAY be
defined on any calendar collection to specify restrictions a CalDAV server
may have on a calendar collection. This property MAY be used to
indicate the media type
supported for the calendar object resources contained in a given
calendar collection (e.g., iCalendar version 2.0).

Definition:

<!ELEMENT calendar-restrictions (calendar-data?)> supported-calendar-data (calendar-data*)>

Example:

<C:calendar-restrictions

<C:supported-calendar-data
xmlns:C="urn:ietf:params:xml:ns:caldav">
<C:calendar-data content-type="text/calendar" version="2.0"/>
</C:calendar-restrictions>

4.4. Calendar Object Resource Restrictions in Calendar Collections

Calendar object resources contained in
</C:supported-calendar-data>

5.3. Creating Resources

The creation of calendar collections MUST NOT
contain more than one type of calendar component (e.g., VEVENT,
VTODO, etc.) with the exception of VTIMEZONE components which MUST be
specified for each unique TZID parameter value specified in the
iCalendar object. For instance, a calendar object resource can
contain two VEVENT components and one VTIMEZONE component, but it
cannot contain one VEVENT component and one VTODO component.

The UID property value of the calendar components contained in a and calendar object resource MUST resources
may be unique in the scope of the calendar
collection, and all its descendant collections, in which initiated by either a CalDAV client or by the calendar
object resource is contained. CalDAV server.

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Calendar components in

For example, a calendar collection that have different UID
property values MUST be stored in separate calendar object resources.

Calendar components server might come preconfigured with the same UID property value, in a given user's calendar
collection, MUST be contained in or the same CalDAV client might request the server to create a
new calendar object
resource. This ensures that all components in collection for a recurrence "set" are
contained in the same given user. Servers might populate
events as calendar object resource. In that case there
will be one component without objects inside a RECURRENCE-ID property (the component
that defines calendar collection, or clients
might request the recurrence pattern) server to create events. Either way, both client
and all server MUST comply with the rest will have that
property (these are requirements in this document, and
MUST understand objects appearing in calendar collections or
according to the recurrence exceptions).

For example, given the following iCalendar object:

BEGIN:VCALENDAR
CALSCALE:GREGORIAN
PRODID:-//Example, Inc.\, Inc.//Example App//EN
VERSION:2.0
BEGIN:VEVENT
UID:1@example.com
SUMMARY:One-off Meeting
DTSTAMP:20041210T183904Z
DTSTART:20041207T120000Z
DTEND:20041207T130000Z
END:VEVENT
BEGIN:VEVENT
UID:2@example.com
SUMMARY:Weekly Meeting
DTSTAMP:20041210T183838Z
DTSTART:20041206T120000Z
DTEND:20041206T130000Z
RRULE:FREQ=WEEKLY
END:VEVENT
BEGIN:VEVENT
UID:2@example.com
RECURRENCE-ID:20041213T120000Z
DTSTAMP:20041210T183838Z
DTSTART:20041213T130000Z
END:VEVENT
END:VCALENDAR

The VEVENT component with the UID value "1@example.com", would be
stored in its own calendar object resource. The two VEVENT
components with the UID value "2@example.com", which represent a
recurring event where one recurrence instance has been overridden,
would be stored in the same calendar object resource.

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4.5. Creating Resources

The creation of calendar collections and calendar object resources
may be initiated by either a CalDAV client or by the CalDAV server.
For example, a server might come preconfigured with a user's calendar
collection, or the CalDAV client might request the server to create a
new calendar collection for a given user. Servers might populate
events as calendar objects inside a calendar collection, or clients
might request the server to create events. Either way, both client
and server MUST comply with the requirements in this document, and
MUST understand objects appearing in calendar collections or
according to the data model defined here.

4.5.1. MKCALENDAR Method

An HTTP request using data model defined here.

5.3.1. MKCALENDAR Method

An HTTP request using the MKCALENDAR method creates a new calendar
collection resource. A server MAY restrict calendar collection
creation to particular collections.

Support for MKCALENDAR on the server is only RECOMMENDED and not
REQUIRED because some calendar stores only support one calendar per
user (or principal) and those are typically pre-created for each
account. However, servers and clients are strongly encouraged to
support MKCALENDAR whenever possible to allow users to create
multiple calendar collections to better help organize their data.

Clients SHOULD use the DAV:displayname property for a human-readable
name of the calendar. Clients can either specify the value of the
DAV:displayname property in the request body of the MKCALENDAR
request, or alternatively issue a PROPPATCH request to change the
DAV:displayname property to the appropriate value immediately after
issuing the MKCALENDAR request. Clients SHOULD NOT set the DAV:
displayname property to be the same as any other calendar collection
at the same URI "level". When displaying calendar collections to
users, clients SHOULD check the DAV:displayname property and use that
value as the name of the calendar. In the event that the DAV:
displayname property is empty, the client MAY use the last part of
the calendar collection URI as the name.

If a MKCALENDAR request fails, the server state preceding the request
MUST be restored.

Marshalling:

If a request body is included, it MUST be a CALDAV:mkcalendar XML
element. Instruction processing MUST occur in the order
instructions are received (i.e., from top to bottom).
Instructions MUST either all be executed or none executed. Thus

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if any error occurs during processing all executed instructions
MUST be undone and a proper error result returned. Instruction
processing details can be found in the definition of the DAV:set
instruction in section 12.13 of [4]. [RFC2518].

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<!ELEMENT mkcalendar (DAV:set)>

If a response body for a successful request is included, it MUST
be a CALDAV:mkcalendar-response XML element.

<!ELEMENT mkcalendar-response ANY>

The response MUST include a Cache-Control:no-cache header.

Preconditions:

(DAV:resource-must-be-null): A resource MUST NOT exist at the
Request-URI.
Request-URI;

(CALDAV:calendar-collection-location-ok): The Request-URI MUST
identify a location where a calendar collection can be created. created;
and

(DAV:needs-privilege): The DAV:bind privilege MUST be granted to
the current user. user on the parent collection of the Request-URI.

Postconditions:

(CALDAV:initialize-calendar-collection): A new calendar collection
exists at the Request-URI. The DAV:resourcetype of the calendar
collection MUST contain both DAV:collection and CALDAV:calendar
XML elements.

4.5.1.1.

5.3.1.1. Status Codes

The following are examples of response codes one would expect to get
in a response to a MKCALENDAR request. Note that this list is by no
mean exhaustive.

201 (Created) - The calendar collection resource was created in
its entirety. entirety;

207 (Multi-Status) - The calendar collection resource was not
created since one or more DAV:set instructions specified in the
request body could not be processed successfully. The following
are examples of response codes one would expect to be used in a
207 (Multi-Status) response:

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403 (Forbidden) - The client, for reasons the server chooses
not to specify, cannot alter one of the properties. properties;

409 (Conflict) - The client has provided a value whose
semantics are not appropriate for the property. This includes
trying to set read-only properties.

424 (Failed Dependency) -

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trying to set read-only properties;

424 (Failed Dependency) - The DAV:set instruction on the
specified resource would have succeeded if it were not for the
failure of another DAV:set instruction specified in the request
body.
body;

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. it; and

507 (Insufficient Storage) - The server did not have sufficient
space to record the property. property;

403 (Forbidden) - This indicates at least one of two conditions:
1) the server does not allow the creation of calendar collections
at the given location in its namespace, or 2) the parent
collection of the Request-URI exists but cannot accept members. members;

405 (Method Not Allowed) - MKCALENDAR can only be executed on a
null resource. resource;

409 (Conflict) - A collection cannot be made at the Request-URI
until one or more intermediate collections have been created. created;

415 (Unsupported Media Type) - The server does not support the
request type of the body. body; and

507 (Insufficient Storage) - The resource does not have sufficient
space to record the state of the resource after the execution of
this method.

4.5.1.2. Example -

5.3.1.2. Example: Successful MKCALENDAR request

This example creates a calendar collection called /home/lisa/tasks/ /home/lisa/
calendars/events/ on the server cal.example.com with specific values
for the properties DAV:displayname, CALDAV:calendar-description CALDAV:calendar-description,
CALDAV:supported-calendar-component-set, and CALDAV:calendar-
component-restriction-set.
timezone.

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>> Request <<

MKCALENDAR /home/lisa/tasks/ /home/lisa/calendars/events/ HTTP/1.1
Host: cal.example.com
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxx xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:mkcalendar xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:set>
<D:prop>
<D:displayname>Lisa's To-dos</D:displayname> Events</D:displayname>
<C:calendar-description xml:lang="en"
>Calendar restricted to to-dos.</C:calendar-description>
<C:calendar-component-restriction-set> events.</C:calendar-description>
<C:supported-calendar-component-set>
<C:comp name="VTODO"/>
</C:calendar-component-restriction-set> name="VEVENT"/>
</C:supported-calendar-component-set>
<C:calendar-timezone><![CDATA[BEGIN:VCALENDAR
PRODID:-//Example Corp.//CalDAV Client//EN
VERSION:2.0
BEGIN:VTIMEZONE
TZID:US-Eastern
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:Eastern Standard Time (US & Canada)
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:Eastern Daylight Time (US & Canada)
END:DAYLIGHT
END:VTIMEZONE
END:VCALENDAR
]]></C:calendar-timezone>
</D:prop>
</D:set>
</C:mkcalendar>

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>> Response <<

HTTP/1.1 201 Created
Cache-Control: no-cache
Date: Fri, 11 Nov 2005 09:32:12 GMT
Content-Length: 0

4.5.2.

5.3.2. Creating Calendar Object Resources

Clients typically populate calendar collections with calendar object resources.
The URL for each calendar object resource is entirely arbitrary, and
does not need to bear a specific relationship (but
might) to the calendar object
resource's subject, scheduled time, UID iCalendar properties (e.g., SUMMARY, UID, DTSTART, etc.)
or other metadata. A new New calendar object resource must have a unique
URL, otherwise the new component would instead resources MUST be created
with a PUT request targeted at an update to unmapped URI. A PUT request
targeted at mapped URI updates an existing calendar object resource.

When servers create new resources, it's not hard for the server to
choose a unique URL. an unmapped URI. It's slightly tougher for clients, because a
client might not want to examine all resources in the collection, and
might not want to lock the entire collection to ensure that a new one
resource isn't created with a name collision. However, there are http
features is an
HTTP feature to mitigate this. If the client intends to create a new
non-collection resource, such as a new VEVENT, the client SHOULD use
the HTTP request header "If-None-Match: *" on the PUT request. The Request-

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URI
Request-URI on the PUT request MUST include the target collection,
where the resource is to be created, plus the name of the resource in
the last path segment. The last path segment could be a random
number, or it could be a sequence number, or a string related to the object's
SUMMARY
calendar object resource's UID property. No matter how the name is chosen, the "If-None-
Match" The "If-None-Match: *"
request header ensures that the client cannot will not inadvertently
overwrite an existing
resource even if it has accidentally chosen a duplicate resource
name.

Servers SHOULD return an ETag header containing the actual ETag of
the newly created resource on a successful creation. resource.

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>> Request <<

PUT /home/lisa/calendar/newevent.ics /home/lisa/calendars/events/qwue23489.ics HTTP/1.1
If-None-Match: *
Host: cal.example.com
Content-Type: text/calendar
Content-Length: xxx xxxx

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
UID:20010712T182145Z-123401@example.com
DTSTAMP:20010712T182145Z
DTSTART:20010714T170000Z
DTEND:20010715T040000Z
SUMMARY:Bastille Day Party
END:VEVENT
END:VCALENDAR

>> Response <<

HTTP/1.1 201 Created
Content-Length: 0
Date: Fri, 11 Nov 2005 09:32:12 GMT
ETag: "123456789-000-111" W/"123456789-000-111"

The request to change an existing event is the same, but with a
specific ETag in the "If-Match" header, rather than the "If-None-
Match" header.

As indicated in Section 3.10 of RFC 2445 [3], [RFC2445], the URL of calendar object
resources containing (an arbitrary set of) calendaring and scheduling
information may be suffixed by ".ics", and the URL of calendar object
resources containing free or busy time information may be suffixed by
".ifb".

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Additional Preconditions for PUT within calendar collections:

(CALDAV:uid-already-exists):

(CALDAV:supported-calendar-data): The component UID chosen is not
unique and resource submitted in the client must choose another if it attempts again.

(CALDAV:invalid-calendar-resource): The iCalendar
PUT request MUST be a supported media type (e.g., iCalendar) for
calendar object syntax or
structure was invalid. (Note that the server MAY support upload
formats other than iCalendar but then resources;

(CALDAV:valid-calendar-data): The resource submitted in the server PUT
request MUST validate
each component uploaded according comply to the chosen format syntax.) specified media type specification
(e.g., iCalendar);

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5. Calendaring Access Control

5.1. Calendaring Privileges

A CalDAV server

(CALDAV:valid-calendar-object-resource): The resource submitted in
the PUT request MUST support WebDAV ACL [9]. WebDAV ACL provides a
framework for an extensible list obey all restrictions specified in
Section 4.1 (e.g., calendar object resources MUST NOT contain more
than one type of privileges on WebDAV collections
and ordinary resources. A CalDAV server calendar component, calendar object resources
MUST also support NOT specify the
calendaring privilege defined iCalendar METHOD property etc.);

(CALDAV:supported-calendar-component): The resource submitted in this section.

5.1.1. CALDAV:read-free-busy Privilege

Calendar users often wish to allow other users to see their busy time
information, without viewing the other details of
the calendar
components (location, summary, attendees). This allows PUT request MUST contain a significant
amount type of privacy while still allowing those other users to schedule
meetings at times when the calendar user component that is likely to be free.

The CALDAV:read-free-busy privilege controls which
supported in the targeted calendar
collections collection; and

(CALDAV:no-uid-conflict): The resource submitted in the PUT
request MUST NOT specify an iCalendar UID property value already
in use in the targeted calendar collection or overwrite an
existing calendar object resources are examined when resource with a free-
busy-query REPORT is run (see Section 6.6). This privilege can calendar object resource
that has a different UID property value.

5.3.3. Calendar Object Resource Entity Tag

The DAV:getetag property MUST be
granted defined on calendar collections or all calendar object
resources.
Servers MUST support this privilege on

A response to a GET request targeted at a calendar collections and any object resource
MUST contain an ETag response header field indicating the current
value of the entity tag of the calendar object resources within those collections.

<!ELEMENT read-free-busy EMPTY>

The CALDAV:read-free-busy privilege is aggregated in the DAV:read
privilege. Note that if an ACL grants the privilege CALDAV:read-
free-busy, the client may not expect to be granted access to GET,
HEAD, OPTIONS and PROPFIND.

5.1.2. Privilege aggregation and the DAV:supported-privilege-set
property

In the WebDAV ACL standard, servers MUST support the DAV:supported-
privilege-set property to show which privileges are abstract, which
privileges are supported, how the privileges relate to one another,
and resource.

A response to provide text descriptions (particularly useful for custom
privileges). The relationships between privileges involves showing
which privilege is a subset or a superset of another privilege. For
example, because reading the ACL property is considered a more
specific privilege than the DAV:read privilege (a subset of PUT request MAY contain an ETag response header field
indicating the total
set current value of actions are allowed), it may be aggregated under the DAV:read
privilege. Although entity tag for the list of supported privileges MAY vary
somewhat from server calendar
object resource just created.

A response to server (the WebDAV ACL specification leaves
room for a fair amount of diversity in server implementations), the
following restriction MUST hold for PUT request with a CalDAV server:

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o The server MUST support the CALDAV:read-free-busy privilege. The
CALDAV:read-free-busy privilege strong entity tag MUST be aggregated under the DAV:
read privilege, and mean that
the server MUST allow CALDAV:read-free-busy to
be granted without granting full read privilege.

5.1.2.1. Partial example of DAV:supported-privilege-set property

This will return on a subsequent GET request a calendar object
resource that is equivalent by octet equality.

A response to a partial example of how PUT request with a weak entity tag MUST mean that the DAV:supported-privilege-set
property could look
server will return on a server supporting CalDAV. Note subsequent GET request a calendar object
resource that
aggregation is shown in equivalent and could be substituted for the structure of the DAV:supported-privilege
elements containing each other.

<D:supported-privilege-set xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:supported-privilege>
<D:privilege><D:all/></D:privilege>
<D:abstract/>
<D:description xml:lang="en"
>Any operation</D:description>
<D:supported-privilege>
<D:privilege><D:read/></D:privilege>
<D:description xml:lang="en"
>Read any object</D:description>
<D:supported-privilege>
<D:privilege><D:read-acl/></D:privilege>
<D:description xml:lang="en"
>Read ACL</D:description>
</D:supported-privilege>
<D:supported-privilege>
<D:privilege><D:read-current-user-privilege-set/>
</D:privilege>
<D:description xml:lang="en"
>Read current user privilege set</D:description>
</D:supported-privilege>
<D:supported-privilege>
<D:privilege>
<C:read-free-busy/>
</D:privilege>
<D:description xml:lang="en"
>Read busy time information</D:description>
</D:supported-privilege>
</D:supported-privilege>
<D:supported-privilege>
<D:privilege><D:write/></D:privilege>
<D:description xml:lang="en"
>Write any object</D:description>
...
</D:supported-privilege>

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</D:supported-privilege-set>

5.2. Additional Principal Properties

This section defines additional properties for WebDAV principal
resources as defined in RFC3744 [9].

5.2.1. CALDAV:calendar-home-set Property

Name: calendar-home-set

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Identify the URL of any WebDAV collections that contains
submitted calendar collections owned by the associated principal resource.

Conformance: This property MAY be protected and SHOULD object resource with no significant change in
semantics.

A response to a PUT request MUST NOT be
returned by contain an ETag response header
field if the server will return on a PROPFIND allprop subsequent GET request (as defined a
calendar object resource that has significant change in Section
12.14.1 of [4]). Support for this property is RECOMMENDED.

Description: The CALDAV:calendar-home-set property is meant to allow
users semantics
compared to easily find the submitted calendar collections owned by object resource. In this case,
the
principal. Typically, users will group all client SHOULD retrieve the calendar
collections that they own under new entity (and ETag) as a common collection. This
property specify basis for
further changes, rather than use the URL of collections that either are calendar
collections or ordinary collections that have child or descendant
calendar collections owned by entity it had sent with the principal.

Definition:

<!ELEMENT calendar-home-set (DAV:href*) >

Example:

<C:calendar-home-set xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:href>http://cal.example.com/home/bernard/calendars/</D:href>
</C:calendar-home-set> PUT
request.

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6. Calendaring Reports

This section defines the reports which a CalDAV server MUST support
on calendar collections and calendar object resources. Access Control

6.1. Calendaring Privilege

CalDAV servers MUST advertise support for those reports with and adhere to the DAV:
supported-report-set property defined in RFC3253 [7].

Some of these reports allow calendar data (from possibly multiple
resources) to be returned.

6.1. REPORT Method

The REPORT method (defined in Section 3.6 requirements of RFC3253 [7]) WebDAV
ACL [RFC3744]. WebDAV ACL provides a framework for an extensible mechanism for obtaining information about a resource.
Unlike the PROPFIND method, which returns the value set
of one or more
named properties, the REPORT method privileges that can involve more complex
processing. REPORT is valuable in cases where the server has access
to all of the information needed be applied to perform the complex request (such
as a query), WebDAV collections and where it would require multiple requests for the
client to retrieve the information needed to perform the same
request.

A server that supports calendar-access ordinary
resources. CalDAV servers MUST also support the DAV:expand-
property report (defined in Section 3.8 of RFC3253 [7]).

6.2. Reports on non-calendar collections

Servers MAY support the REPORTs calendaring
privilege defined in this specification on non-
calendar collections. In computing responses section.

6.1.1. CALDAV:read-free-busy Privilege

Calendar users often wish to the REPORTs defined
in this specification, servers MUST only consider calendar object
resources contained in calendar collections, subject also allow other users to see their busy time
information, without viewing the
value other details of the Depth request header.

If these REPORTs are supported on ordinary collections the server
advertises the capability with the DAV:supported-report-set property
as already described.

6.3. Reports and recurring items

Some calendar
components (location, summary, attendees). This allows a significant
amount of privacy while still allowing other users to schedule
meetings at times when the reports defined in CalDAV can user is likely to be targetted at free.

The CALDAV:read-free-busy privilege controls which calendar
collections and calendar object resources within a specific time range. To determine whether are examined when a CALDAV:
free-busy-query REPORT request is processed (see Section 7.8). This
privilege can be granted on calendar collections or calendar object resource matches the time range filter element, the
start
resources. Servers MUST support this privilege on all calendar
collections and end times for the particular type of calendar object are determined
and then compared resources.

<!ELEMENT read-free-busy EMPTY>

The CALDAV:read-free-busy privilege MUST be aggregated in the DAV:
read privilege. Servers MUST allow the CALDAV:read-free-busy to be
granted without the requested time range. If DAV:read privilege being granted.

Clients should note that when only the start CALDAV:read-free-busy
privilege has been granted on a resource, this does not imply access
to GET, HEAD, OPTIONS and end
overlap the requested time range, then PROPFIND on the calendar object resource
matches -- those
operations are governed by the filter element. The rules DAV:read privilege.

6.2. Additional Principal Property

This section defines an additional property for WebDAV principal
resources as defined in [3] for determining
the actual start and end times of calendar components MUST be used. [RFC3744].

6.2.1. CALDAV:calendar-home-set Property

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Name: calendar-home-set

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Identifies the requested
time range. If URL of any one instance overlaps the time range, then the WebDAV collections that contain
calendar object resource matches the filter element.

In addition, CalDAV provides three ways to determine which recurrence
instances are returned from collections owned by the recurrence set. The three options
are:

1. Return all the calendar components contained in the calendar
object resources. associated principal resource.

Conformance: This includes the recurrence instance that
defines the recurrence pattern, referred to as the "master
instance", as well as the recurrence instances that define
exceptions to the recurrence pattern, referred to as the
"overriden instances". Because of the rules property MAY be protected and SHOULD NOT be
returned by a PROPFIND allprop request (as defined in Section 4.1.2 all recurrence instances
12.14.1 of a recurring component
will always be in [RFC2518]). Support for this property is RECOMMENDED.

Description: The CALDAV:calendar-home-set property is meant to allow
users to easily find the same calendar object resource.

2. Return collections owned by the "master" instance and only
principal. Typically, users will group all the "overridden instances" calendar
collections that overlap the specified time range. they own under a common collection. This avoids
property specify the need for
clients to process recurrence instances outside URL of the time range
they collections that either are interested in.

3. Return an "expanded" set of calendar components that represent
only those instances in the recurrence set
collections or ordinary collections that overlap have child or descendant
calendar collections owned by the
specified time range. principal.

Definition:

<!ELEMENT calendar-home-set (DAV:href*)>

Example:

<C:calendar-home-set xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:href>http://cal.example.com/home/bernard/calendars/</D:href>
</C:calendar-home-set>

7. Calendaring Reports

This avoids the need for clients to do any
recurrence processing themselves as the server does section defines the expansion
for them REPORTs that CalDAV servers MUST support on
calendar collections and provides the list of instances.

6.4. CALDAV:calendar-query Report

The CALDAV:calendar-query REPORT performs a search calendar object resources.

CalDAV servers MUST advertise support for these REPORTs on all
calendar collections and calendar object resources that match a specified search filter. The response
of this report will contain all the WebDAV properties and calendar
object resource data specified in the request. In the case of the
CALDAV:calendar-data XML element, one can explicitly specify with the
calendar components and properties that should be returned DAV:
supported-report-set property defined in the
calendar object resource data that matches the search filter.

The format Section 3.1.5 of this report is modeled [RFC3253].
CalDAV servers MAY also advertise support for these REPORTs on the PROPFIND method. The
request and response bodies
ordinary collections.

Some of the CALDAV:calendar-query report use
XML elements that are also used by PROPFIND. In particular the
request can include XML elements to request WebDAV properties these REPORTs allow calendar data (from possibly multiple
resources) to be returned. When that occurs the response should follow the same
behavior as PROPFIND with respect to the DAV:multistatus response
elements used to return specific property results. For instance, a

7.1. REPORT Method

The REPORT method (defined in Section 3.6 of [RFC3253]) provides an

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request to retrieve

extensible mechanism for obtaining information about one or more
resources. Unlike the PROPFIND method, which returns the value of a property which does not exist is
an error and MUST be noted with a response XML element which contains
a 404 (Not Found) status value.

Support for
one or more named properties, the CALDAV:calendar-query REPORT method can involve more
complex processing. REPORT is REQUIRED.

Marshalling:

The valuable in cases where the server has
access to all of the information needed to perform the complex
request body MUST be a CALDAV:calendar-query XML element (such as
defined in Section 8.1.

The response body for a successful request MUST be a DAV:
multistatus XML element (i.e., query), and where it would require multiple
requests for the response uses client to retrieve the information needed to perform
the same format
as request.

CalDAV servers MUST support the response for PROPFIND). In DAV:expand-property REPORT defined in
Section 3.8 of [RFC3253].

7.2. Ordinary collections

Servers MAY support the case where there REPORTs defined in this document on ordinary
collections, that is, collections that are no
response elements, not calendar collections.
In computing responses to the returned DAV:multistatus XML element is
empty.

The response body for a successful CALDAV:calendar-query REPORT
request REPORTs defined in this document,
servers MUST contain a DAV:response element for each iCalendar only consider calendar object resources contained in
calendar collections, subject also to the value of the Depth request
header.

7.3. Date and floating time

iCalendar provides a way to specify DATE and DATE-TIME values that matched
are not bound to any time zone in particular, hereafter called
"floating date" and "floating time" respectively. These values are
used to represent the search filter. Calendar data same day, hour, minute and second value
regardless of which time zone is being
returned observed. For instance, the
DATE value "20051111", represents November 11th, 2005 in no specific
time zone, while the CALDAV:calendar-data XML element inside DATE-TIME value "20051111T111100" represents
November 11th, 2005 at 11:11 AM in no specific time zone.

CalDAV servers may need to convert "floating date" and "floating
time" values in date with UTC time values in the DAV:
propstat XML element.

Preconditions:

None.

Postconditions:

(DAV:number-of-matches-within-limits): The number processing of matching
calendar object resources must fall within server-specific,
predefined limits.
calendaring REPORT requests.

For example, this condition might be triggered
if a search specification would cause the return CALDAV:calendar-query REPORT, CalDAV servers MUST rely on the
value of an the CALDAV:timezone XML element, if specified as part of the
request body, to perform the proper conversion of "floating date" and
"floating time" values to date with UTC time values. If the CALDAV:
timezone XML element is not specified in the request body, CalDAV
servers MUST rely on the value of the CALDAV:calendar-timezone
property, if defined, else the CalDAV servers MAY rely on the time
zone of their choice.

For the CALDAV:free-busy-query REPORT, CalDAV servers MUST rely on
the value of the CALDAV:calendar-timezone property, if defined, to
compute the proper FREEBUSY time period value as date with UTC time,

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for calendar components scheduled with "floating date" or "floating
time". If the CALDAV:calendar-timezone property is not defined,
CalDAV servers MAY rely on the time zone of their choice.

7.4. Time range filtering

Some of the reports defined in this section can be targeted at
calendar object resources within a specific time range. To determine
whether a calendar object resource matches the time range filter
element, the start and end times for the particular type of object
are determined and then compared to the requested time range. If the
start and end overlap the requested time range, then the calendar
object resource matches the filter element. The rules defined in
[RFC2445] for determining the actual start and end times of calendar
components MUST be used, along with the rules for determining overlap
specified in Section 9.8 of this document.

When such time range filtering is used, special consideration must be
given to recurring calendar components such as VEVENT and VTODO
components. The server MUST expand recurring components to determine
whether any recurrence instances overlap the specified time range.
If one or more recurrence instances overlap the time range, then the
calendar object resource matches the filter element.

7.5. Returned calendar components

In addition, CalDAV provides three ways to determine which components
of a calendar object resource are returned from the recurrence set.
The three options are:

1. Return all the calendar components contained in the calendar
object resources. This includes the component that defines the
recurrence set, referred to as the "master component", as well as
the components that define exceptions to the recurrence set,
referred to as the "overridden components". According to the
rules defined in Section 3.2 all recurrence instances of a
recurring component will always be contained in the same calendar
object resource.

2. Return the "master component" and only the "overridden
components" that currently or originally overlap the specified
time range. This avoids the need for clients to process
"overridden components" outside of the time range they are
interested in. See Section 9.5.6.

3. Return "expanded" calendar components that represent only those
recurrence instances in the recurrence set that overlap the
specified time range. This avoids the need for clients to do any

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recurrence processing themselves as the server does the expansion
for them and provides the list of instances. See Section 9.5.5.

7.6. CALDAV:calendar-query Report

The CALDAV:calendar-query REPORT performs a search for all calendar
object resources that match a specified filter. The response of this
REPORT will contain all the WebDAV properties and calendar object
resource data specified in the request. In the case of the CALDAV:
calendar-data XML element, one can explicitly specify the calendar
components and properties that should be returned in the calendar
object resource data that matches the filter.

The format of this REPORT is modeled on the PROPFIND method. The
request and response bodies of the CALDAV:calendar-query REPORT use
XML elements that are also used by PROPFIND. In particular the
request can include XML elements to request WebDAV properties to be
returned. When that occurs the response should follow the same
behavior as PROPFIND with respect to the DAV:multistatus response
elements used to return specific property results. For instance, a
request to retrieve the value of a property which does not exist is
an error and MUST be noted with a response XML element which contains
a 404 (Not Found) status value.

Support for the CALDAV:calendar-query REPORT is REQUIRED.

Marshalling:

The request body MUST be a CALDAV:calendar-query XML element as
defined in Section 9.4.

The response body for a successful request MUST be a DAV:
multistatus XML element (i.e., the response uses the same format
as the response for PROPFIND). In the case where there are no
response elements, the returned DAV:multistatus XML element is
empty.

The response body for a successful CALDAV:calendar-query REPORT
request MUST contain a DAV:response element for each iCalendar
object that matched the search filter. Calendar data is being
returned in the CALDAV:calendar-data XML element inside the DAV:
propstat XML element.

Preconditions:

(CALDAV:supported-calendar-data): The attributes "content-type"
and "version" of the CALDAV:calendar-data XML elements specify a
media type supported by the server for calendar object resources.

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(CALDAV:valid-filter): The CALDAV:filter XML element specified in
the REPORT request MUST be valid. For instance, a CALDAV:filter
cannot nest a <C:comp name="VEVENT"> element in a <C:comp
name="VTODO"> element, or a CALDAV:filter cannot nest a <C:time-
range start="..." end="..."> element in a <C:prop name="SUMMARY">
element.

Postconditions:

(DAV:number-of-matches-within-limits): The number of matching
calendar object resources must fall within server-specific,
predefined limits. For example, this condition might be triggered
if a search specification would cause the return of an extremely
large number of responses.

6.4.1. responses.

7.6.1. Example: Partial retrieval of events by time range

In this example, the client requests the server to return specific
components and properties of the VEVENT components that overlap the
time range from September 2nd, 2004 at 00:00:00 am UTC to September
3rd, 2004 at 00:00:00 am UTC. In addition the DAV:getetag property
is also requested and returned as part of the response. Note that
the third calendar object returned is a recurring event whose first
instance lies outside of the requested time range, but whose second
instance does overlap the time range. Note also that there are no
restrictions on what part of the calendar data to return, thus the
server will return all components and and properties.

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>> Request <<

REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-query xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop>
<D:getetag/>
<C:calendar-data>
<C:comp name="VCALENDAR">
<C:allprop/>
<C:comp name="VEVENT">
<C:prop name="X-ABC-GUID"/>
<C:prop name="UID"/>
<C:prop name="DTSTART"/>
<C:prop name="DTEND"/>
<C:prop name="DURATION"/>
<C:prop name="EXDATE"/>
<C:prop name="EXRULE"/>
<C:prop name="RDATE"/>
<C:prop name="RRULE"/>
<C:prop name="LOCATION"/>
<C:prop name="SUMMARY"/>
</C:comp>
<C:comp name="VTIMEZONE">
<C:allprop/>
<C:allcomp/>
</C:comp>
</C:comp>
</C:calendar-data>
</D:prop>
<C:filter>
<C:comp-filter name="VCALENDAR">
<C:comp-filter name="VEVENT">
<C:time-range start="20040902T000000Z"
end="20040903T000000Z"/>
</C:comp-filter>
</C:comp-filter>
</C:filter>
</C:calendar-query>

>> Response <<

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HTTP/1.1 207 Multi-Status
Date: Fri, 11 Nov 2005 09:32:12 GMT
Content-Type: application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/ev102.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>W/"23ba4d-ff11fb"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
DTSTAMP:20040901T134532Z
DTSTART:20040902T100000Z
DTEND:20040902T120000Z
SUMMARY:Design meeting
UID:34222-232@example.com
X-ABC-GUID:E1CX4zp-0005Ld-21@example.com
END:VEVENT
END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/mtg103.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>W/"ff11fb-23ba4d"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
DTSTAMP:20040901T112321Z
DTSTART:20040902T130000Z
DTEND:20040902T150000Z
SUMMARY:Design meeting - Part II
UID:63409-868@example.com
X-ABC-GUID:E1CX5Dr-0007ym-Hz@example.com
END:VEVENT

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END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/mtg104.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>W/"7834cd-63fd2c"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
DTSTAMP:20040901T103256Z
DTSTART:20040901T130000Z
DTEND:20040901T150000Z
RRULE:FREQ=DAILY;COUNT=2
SUMMARY:Design meeting - Part III
UID:63409-451@example.com
X-ABC-GUID:E1CX5Dr-0008ym-Hz@example.com
END:VEVENT
END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>

7.6.2. Example: Partial retrieval of recurring events by time range

In this example, the client requests the server to return specific
components and properties of the VEVENT
components that overlap the time range from September 2nd, 2004 June 1st, 2005 at
00:00:00 am UTC to September
3rd, 2004 June 9th, 2005 at 00:00:00 am UTC. In addition the DAV:getetag property
is also requested and returned as part Use of the response. Note that
the third calendar object returned is a recurring event whose first
instance lies outside of
CALDAV:limit-recurrence-set element causes the requested time range, but whose second
instance does server to only return
overridden recurrence instances that overlap the time range. range specified
in that element.

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>> Request <<

REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-query xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop>
<D:getetag/>
<C:calendar-data>
<C:comp name="VCALENDAR">
<C:allprop/>
<C:comp name="VEVENT">
<C:prop name="X-ABC-GUID"/>
<C:prop name="UID"/>
<C:prop name="DTSTART"/>
<C:prop name="DTEND"/>
<C:prop name="DURATION"/>
<C:prop name="EXDATE"/>
<C:prop name="EXRULE"/>
<C:prop name="RDATE"/>
<C:prop name="RRULE"/>
<C:prop name="LOCATION"/>
<C:prop name="SUMMARY"/>
</C:comp>
<C:comp name="VTIMEZONE">
<C:allprop/>
<C:allcomp/>
</C:comp>
</C:comp>
<C:limit-recurrence-set start="20050601T000000Z"
end="20050609T000000Z"/>
</C:calendar-data>
</D:prop>
<C:filter>
<C:comp-filter name="VCALENDAR">
<C:comp-filter name="VEVENT">
<C:time-range start="20040902T000000Z"
end="20040903T000000Z"/> start="20050601T000000Z"
end="20050609T000000Z"/>
</C:comp-filter>
</C:comp-filter>
</C:filter>
</C:calendar-query>

Assuming that only the following recurring VEVENT components contains
recurrence instances scheduled to overlap the specified time range:

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BEGIN:VCALENDAR
PRODID:-//Example Corp.//CalDAV Client//EN
VERSION:2.0
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
DTSTART;TZID=US-Eastern:20050601T100000
RRULE:FREQ=WEEKLY;COUNT=3
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Meeting room 17026
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
RECURRENCE-ID:20050615T050000Z
DTSTART:20050615T050000Z
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Conference room 18044
END:VEVENT
BEGIN:VTIMEZONE
TZID:US-Eastern
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:Eastern Standard Time (US &amp; Canada)
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:Eastern Daylight Time (US &amp; Canada)
END:DAYLIGHT
END:VTIMEZONE
END:VCALENDAR

The server will omit the calendar component describing the recurrence
instance scheduled on June 15, 2005 in its response to the client.

>> Response <<

HTTP/1.1 207 Multi-Status
Date: Fri, 11 Nov 2005 09:32:12 GMT

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HTTP/1.1 207 Multi-Status

Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/ev102.ics</D:href>
>http://cal.example.com/home/bernard/calendar/ev204.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>"23ba4d-ff11fb"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
VERSION:2.0
BEGIN:VEVENT
DTSTART:20040902T100000Z
DTEND:20040902T120000Z
SUMMARY:Design meeting
UID:34222-232@example.com
X-ABC-GUID:E1CX4zp-0005Ld-21@example.com
DTSTAMP:20050507T203312Z
UID:uid742@example.com
DTSTART;TZID=US-Eastern:20050601T100000
RRULE:FREQ=WEEKLY;COUNT=3
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Meeting room 17026
END:VEVENT
BEGIN:VTIMEZONE
TZID:US-Eastern
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE
END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/mtg103.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>"ff11fb-23ba4d"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
DTSTART:20040902T130000Z
DTEND:20040902T150000Z
SUMMARY:Design meeting - Part II
UID:63409-868@example.com
X-ABC-GUID:E1CX5Dr-0007ym-Hz@example.com
END:VEVENT
END:VCALENDAR
</C:calendar-data>
</D:prop>
</D:multistatus>

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<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/mtg104.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>"7834cd-63fd2c"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
DTSTART:20040901T130000Z
DTEND:20040901T150000Z
RRULE:FREQ=DAILY;COUNT=2
SUMMARY:Design meeting - Part III
UID:63409-451@example.com
X-ABC-GUID:E1CX5Dr-0008ym-Hz@example.com
END:VEVENT
END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>

6.4.2.

7.6.3. Example: Partial Expanded retrieval of recurring events

In this example, the client requests the server to return VEVENT
components that overlap the time range from June 1st, 2005 at
00:00:00 am UTC to June 9th, 2005 at 00:00:00 am UTC. UTC and to return
recurring calendar components expanded into individual recurrence
instance calendar components. Use of the
CALDAV:limit-recurrence-set CALDAV:expand element
causes the server to only return overridden recurrence instances that
overlap the time range specified in that element.

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>> Request <<

REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-query xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop>
<C:calendar-data>
<C:limit-recurrence-set
<C:expand start="20050601T000000Z"
end="20050609T000000Z"/>
</C:calendar-data>
</D:prop>
<C:filter>
<C:comp-filter name="VCALENDAR">
<C:comp-filter name="VEVENT">
<C:time-range start="20050601T000000Z"
end="20050609T000000Z"/>
</C:comp-filter>
</C:comp-filter>
</C:filter>
</C:calendar-query>

Assuming that only the following recurring VEVENT components contains
recurrence instances scheduled to overlap the specified time range:

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BEGIN:VCALENDAR
PRODID:-//Example Corp.//CalDAV Client//EN
VERSION:2.0
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
DTSTART;TZID=America/Montreal:20050601T100000
DTSTART;TZID=US-Eastern:20050601T100000
RRULE:FREQ=WEEKLY;COUNT=3
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Meeting room 17026
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
RECURRENCE-ID:20050615T050000Z
DTSTART:20050615T050000Z
RECURRENCE-ID:20050615T140000Z
DTSTART:20050615T140000Z
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Conference room 18044
END:VEVENT
BEGIN:VTIMEZONE
TZID:US-Eastern
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:Eastern Standard Time (US &amp; Canada)
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:Eastern Daylight Time (US &amp; Canada)
END:DAYLIGHT
END:VTIMEZONE
END:VCALENDAR

The server will omit to return the recurring calendar component describing expanded into
two recurrence instances omitting the recurrence instance scheduled
on June 15, 2005 in its response to given that it does not overlap the
client. specified time
range for the expansion of the recurrence set.

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>> Response <<

HTTP/1.1 207 Multi-Status
Date: Fri, 11 Nov 2005 09:32:12 GMT
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/ev204.ics</D:href>
<D:propstat>
<D:prop>
<C:calendar-data>BEGIN:VCALENDAR
PRODID:-//Example Corp.//CalDAV Client//EN
VERSION:2.0
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
DTSTART;TZID=America/Montreal:20050601T100000
RRULE:FREQ=WEEKLY;COUNT=3
RECURRENCE-ID:20050601T140000Z
DTSTART:20050601T140000Z
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Meeting room 17026
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
RECURRENCE-ID:20050608T140000Z
DTSTART:20050608T140000Z
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Meeting room 17026
END:VEVENT
END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>

6.4.3.

7.6.4. Example: Expanded Partial retrieval of recurring events stored free busy components

In this example, the client requests request the server to return VEVENT the
VFREEBUSY components that have free busy information that overlap the

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time range from June 1st, 2005 at 00:00:00 am UTC (inclusively) to
June 9th, 2005 at 00:00:00 am UTC and to return
recurring calendar components expanded into individual recurrence
instance calendar components. am UTC (exclusively). Use of the CALDAV:expand-recurrence-
set CALDAV:
limit-freebusy-set element causes the server to only return overridden recurrence
instances the
FREEBUSY property values that overlap the time range specified in
that element.

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the calendar owner is busy (the CALDAV:free-busy-query REPORT is used
for that purpose, combining VEVENT busy times as well as VFREEBUSY
blocks of time).

>> Request <<

REPORT /home/bernard/calendar/ /home/bernard/calendars/work/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-query xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop>
<C:calendar-data>
<C:expand-recurrence-set
<C:limit-freebusy-set start="20050601T000000Z"
end="20050609T000000Z"/>
</C:calendar-data>
</D:prop>
<C:filter>
<C:comp-filter name="VCALENDAR">
<C:comp-filter name="VEVENT"> name="VFREEBUSY">
<C:time-range start="20050601T000000Z"
end="20050609T000000Z"/>
</C:comp-filter>
</C:comp-filter>
</C:filter>
</C:calendar-query>

Assuming that only the following recurring VEVENT components contains
recurrence instances scheduled to overlap the specified time range:

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BEGIN:VCALENDAR
PRODID:-//Example Corp.//CalDAV Client//EN
VERSION:2.0
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
DTSTART;TZID=America/Montreal:20050601T100000
RRULE:FREQ=WEEKLY;COUNT=3
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Meeting room 17026
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
RECURRENCE-ID:20050615T140000Z
DTSTART:20050615T140000Z
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Conference room 18044
END:VEVENT
END:VCALENDAR

The server will return the recurring calendar component expanded into
two recurrence instances omitting the recurrence instance scheduled
on June 15, 2005 given that it does not overlap the specified time
range for the expansion of the recurrence set.

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>> Response <<

HTTP/1.1 207 Multi-Status
Date: Fri, 11 Nov 2005 09:32:12 GMT
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/ev204.ics</D:href>

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>http://cal.example.com/home/bernard/calendars/work/fb213.ifb<
/D:href>
<D:propstat>
<D:prop>
<D:getetag>W/"87ae34-ee34ab"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VFREEBUSY
ORGANIZER;CN="Bernard Desruisseaux":mailto:bernard@example.com
UID:76ef34-54a3d2@example.com
DTSTAMP:20050530T123421Z
DTSTART:20050327T100000Z
DTEND:20051205T170000Z
FREEBUSY:20050531T230000Z/20050601T010000Z
FREEBUSY;FBTYPE=BUSY-TENTATIVE:20050602T100000Z/20050602T120000Z
FREEBUSY:20050602T110000Z/20050602T143000Z
FREEBUSY:FBTYPE=BUSY-UNAVAILABLE:20050603T090000Z/20050603T103000Z
FREEBUSY:20050604T110000Z/20050604T133000Z
FREEBUSY:20050608T220000Z/20050609T010000Z
END:VFREEBUSY
END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendars/work/fb465.ifb<
/D:href>
<D:propstat>
<D:prop>
<D:getetag>W/"ff11fb-23ba4d"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
RECURRENCE-ID:20050601T140000Z
DTSTART:20050601T140000Z
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Meeting room 17026
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20050507T203312Z
UID:uid742@example.com
RECURRENCE-ID:20050608T140000Z
DTSTART:20050608T140000Z
DURATION:PT1H
SUMMARY:Team Meeting
LOCATION:Meeting room 17026
END:VEVENT
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VFREEBUSY
ORGANIZER;CN="Bernard Desruisseaux":mailto:bernard@example.com
UID:89c5c6-a3b8e0@example.com
DTSTAMP:20050527T184312Z
DTSTART:20050328T110000Z
DTEND:20051106T180000Z
FREEBUSY:20050603T100000Z/20050603T120000Z
FREEBUSY:20050603T140000Z/20050603T143000Z
FREEBUSY:20050604T090000Z/20050604T103000Z
FREEBUSY:20050605T110000Z/20050605T133000Z
END:VFREEBUSY

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END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>

6.4.4.

7.6.5. Example: Retrieval of to-dos by alarm time range

In this example, the client requests the server to return the VTODO
components that have an alarm trigger scheduled in the specified time
range.

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range.

>> Request <<

REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-query xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop xmlns:D="DAV:">
<D:getetag/>
<C:calendar-data/>
</D:prop>
<C:filter>
<C:comp-filter name="VCALENDAR">
<C:comp-filter name="VTODO">
<C:comp-filter name="VALARM">
<C:time-range start="20041121T000000Z"
end="20041122T000000Z"/>
</C:comp-filter>
</C:comp-filter>
</C:comp-filter>
</C:filter>
</C:calendar-query>

6.4.5.

7.6.6. Example: Retrieval of event by UID

In this example, the client requests the server to return the VEVENT
component that has the UID property set to
"20041121-FEEBDAED@foo.org".

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>> Request <<

REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-query xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop xmlns:D="DAV:">
<D:getetag/>
<C:calendar-data/>
</D:prop>
<C:filter>
<C:comp-filter name="VCALENDAR">
<C:comp-filter name="VEVENT">
<C:prop-filter name="UID">
<C:text-match
caseless="no">20041121-FEEBDAED@foo.org</C:text-match>
</C:prop-filter>
</C:comp-filter>
</C:comp-filter>
</C:filter>
</C:calendar-query>

6.4.6.

7.6.7. Example: Retrieval of events by participation status PARTSTAT

In this example, the client requests the server to return the VEVENT
components that have the ATTENDEE property with the value
"mailto:bernard@example.com" and for which the PARTSTAT parameter is
set to "NEEDS-ACTION".

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>> Request <<

REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-query xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop xmlns:D="DAV:">
<D:getetag/>
<C:calendar-data/>
</D:prop>
<C:filter>
<C:comp-filter name="VCALENDAR">
<C:comp-filter name="VEVENT">
<C:prop-filter name="ATTENDEE"/>
<C:text-match
caseless="yes">mailto:bernard@example.com</C:text-match>
<C:param-filter name="PARTSTAT"/>
<C:text-match caseless="yes">NEEDS-ACTION</C:text-match>
</C:param-filter>
</C:prop-filter>
</C:comp-filter>
</C:comp-filter>
</C:filter>
</C:calendar-query>

6.4.7.

7.6.8. Example: Retrieval of events only

In this example, the client requests the server to return all VEVENT
components.

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>> Request <<

REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

6.5.

7.7. CALDAV:calendar-multiget Report

The CALDAV:calendar-multiget REPORT is used to retrieve specific
calendar object resources from within a collection, if the Request-
URI is a collection, or to retrieve a specific calendar object
resource, if the Request-URI is a calendar object resource. This
report
REPORT is similar to the CALDAV:calendar-query REPORT (see
Section 6.4), 7.6), except that it takes a list of DAV:href elements
instead of a CALDAV:filter element to determine which calendar object
resources to return.

Support for the calendar-multiget REPORT is REQUIRED.

Marshalling:

The request body MUST be a CALDAV:calendar-multiget XML element
(see Section 8.5, which MUST contain at least one DAV:href XML
element, and one optional CALDAV:calendar-data element as defined
in Section 8.2. 9.9). If the Request-URI is a collection resource,
then the DAV:href elements MUST refer to resources within that
collection, and they MAY refer to resources at any depth within
the collection. As a result the "Depth" header MUST be ignored by
the server and SHOULD NOT be sent by the client. If the Request-
URI refers to a non-collection resource, then there MUST be a
single DAV:href element that is equal equivalent to the Request-URI.

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The response body for a successful request MUST be a DAV:
multistatus XML element. In the case where there are no response
elements, the returned DAV:multistatus XML element is empty.

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The response body for a successful CALDAV:calendar-multiget REPORT
request MUST contain a DAV:response element for each calendar
object resource referenced by the provided set of DAV:href
elements. Calendar data is being returned in the CALDAV:calendar-
data element inside the DAV:prop element.

In the case of an error accessing any of the provided DAV:href
resources, the server MUST return the appropriate error status
code in the DAV:status element of the corresponding DAV:response
element.

Preconditions:

None.

(CALDAV:supported-calendar-data): The attributes "content-type"
and "version" of the CALDAV:calendar-data XML elements specify a
media type supported by the server for calendar object resources.

Postconditions:

None.

6.5.1.

7.7.1. Example: Successful CALDAV:calendar-multiget Report

In this example, the client requests the server to return specific
properties of the VEVENT components referenced by specific URIs. In
addition the DAV:getetag property is also requested and returned as
part of the response. Note that in this example, the resource at
http://cal.example.com/home/bernard/calendar/mtg1.ics does not exist,
resulting in an error status response.

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>> Request <<

REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-multiget xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop>
<D:getetag/>
<C:calendar-data>
<C:comp name="VCALENDAR">
<C:allprop/>
<C:comp name="VEVENT">
<C:prop name="UID"/>
<C:prop name="DTSTART"/>
<C:prop name="DTEND"/>
<C:prop name="DURATION"/>
<C:prop name="EXDATE"/>
<C:prop name="EXRULE"/>
<C:prop name="RDATE"/>
<C:prop name="RRULE"/>
<C:prop name="LOCATION"/>
<C:prop name="SUMMARY"/>
</C:comp>
<C:comp name="VTIMEZONE">
<C:allprop/>
<C:allcomp/>
</C:comp>
</C:comp>
</C:calendar-data>
<C:calendar-data/>
</D:prop>
<D:href
>http://cal.example.com/home/bernard/calendar/ev102.ics</D:href>
<D:href
>http://cal.example.com/home/bernard/calendar/mtg1.ics</D:href>
<D:href>/home/bernard/calendar/ev102.ics</D:href>
<D:href>/home/bernard/calendar/mtg1.ics</D:href>
</C:calendar-multiget>

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>> Response <<

HTTP/1.1 207 Multi-Status
Date: Fri, 11 Nov 2005 09:32:12 GMT
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/ev102.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>"23ba4d-ff11fb"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
DTSTAMP:20040901T092345Z
DTSTART:20040902T100000Z
DTEND:20040902T120000Z
SUMMARY:Design meeting
UID:34222-232@example.com
END:VEVENT
END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href
>http://cal.example.com/home/bernard/calendar/mtg1.ics</D:href>
<D:status>HTTP/1.1 404 Resource not found</D:status> Not Found</D:status>
</D:response>
</D:multistatus>

6.6.

7.8. CALDAV:free-busy-query Report

The CALDAV:free-busy-query REPORT generates a VFREEBUSY component
containing free busy information for all relevant calendar components
within the calendar collections object
resources targeted by the request and which have the CALDAV:read-free-busy CALDAV:read-
free-busy or DAV:read privilege granted for to the current user.

Only VEVENT components, components without a TRANSP property or with the TRANSP
property set to a TRANSP
property set to "OPAQUE", and VFREEBUSY components SHOULD be

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considered to generate the free busy time information.

In the case of VEVENT components, the free or busy time type (FBTYPE)
of the FREEBUSY properties in the returned VFREEBUSY component SHOULD
be derived from the value of the TRANSP and STATUS properties as
outlined in the table below:

+---------------------------++------------------+
| VEVENT || VFREEBUSY |
+-------------+-------------++------------------+
| TRANSP | STATUS || FBTYPE |
+=============+=============++==================+
| | CONFIRMED || BUSY |
| | (default) || |
| OPAQUE +-------------++------------------+
| (default) | CANCELLED || FREE |
| +-------------++------------------+
| | TENTATIVE || BUSY-TENTATIVE |
| +-------------++------------------+
| | x-name || BUSY or |
| | || x-name |
+-------------+-------------++------------------+
| | CONFIRMED || |
| TRANSPARENT | CANCELLED || FREE |
| | TENTATIVE || |
| | x-name || |
+-------------+-------------++------------------+

Duplicate busy time periods with the same FBTYPE parameter value other than "TRANSPARENT", and VFREEBUSY
components are used to generate
SHOULD NOT be specified in the free returned VFREEBUSY component. Servers
SHOULD coalesce consecutive or overlapping busy time information.

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same type. Busy time periods with different FBTYPE parameter values
MAY overlap.

Support for the CALDAV:free-busy-query REPORT is REQUIRED.

Marshalling:

The request body MUST be a CALDAV:free-busy-query XML element (see
Section 8.6, 9.10, which MUST contain at least exactly one CALDAV:time-range XML
element, as defined in Section 8.4. 9.8.

The response body for a successful request MUST be MAY include a DAV:
multistatus XML element. In the case where there are Depth header. If no response
elements, the returned DAV:multistatus XML element Depth header is empty.
included, Depth:0 is assumed.

The response body for a successful CALDAV:free-busy-query REPORT request MUST contains a DAV:response element for each calendar
collection for which free-busy information has been computed.
Each DAV:response element contains a single CALDAV:calendar-data
XML element as defined in Section 8.2. The CALDAV:calendar-data
XML element MUST contain be an iCalendar
object with a single that contains exactly one VFREEBUSY component, with zero or more FREEBUSY property values component that describe
describes the busy time intervals for the calendar object
resources being targeted, and with other properties set according
to the rules of iCalendar. This report only returns busy time
information. Applications desiring free time information MUST
infer this from available busy time information.

When the Request-URI for a CALDAV:free-busy-query REPORT is a
calendar collection, the free-busy data is implicitly determined from
the calendar object resources containing VEVENT and VFREEBUSY
components within the calendar collection, irrespective of the value
of any Depth header included in the REPORT request. Only calendar
object

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resources containing VEVENT or VFREEBUSY components that have satisfy
the CALDAV:read-free-busy privilege granted to Depth value and for which the current user will
be computed in the response.

When the Request-URI for a CALDAV:free-busy-query REPORT is a non-
calendar collection, the scope of the report is governed by the value
of the Depth header in at least granted
the request as follows:

Depth: 0 - an empty VFREEBUSY component will be returned as there
is CALDAV:read-free-busy privilege. If no valid calendar data object
resource are found to satisfy these conditions a VFREEBUSY
component with no FREEBUSY property MUST be scanned on returned. This REPORT
only returns busy time information. Free time information can be
inferred from the collection.

Depth: 1 - free-busy data for any calendar collections immediately
within returned busy time information.

If the target collection current user is returned.

Depth: infinity - free-busy data for all calendar collections
within any sub-collections of not granted the target collection is returned.

Note that as per DAV:read privilege on the requirements of Section 6.3
Request-URI, the server CALDAV:free-busy-query REPORT request MUST

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expand any recurring items to determine whether any instances
contribute to the free busy information in fail
and return a 404 (Not Found) status value. This restriction will
prevent users from discovering URLs of resources for which they
are only granted the requested time range. CALDAV:read-free-busy privilege.

Preconditions:

None.

Postconditions:

(DAV:number-of-matches-within-limits): The number of matching
calendar object resources must fall within server-specific,
predefined limits. For example, this condition postcondition might be triggered fail if a search specification
the specified CALDAV:time-range would cause the return of an extremely large
number of responses.

6.6.1. calendar object resources to be considered to compute the
response.

7.8.1. Example: Successful CALDAV:free-busy-query Report

In this example, the client requests the server to return free-busy free busy
information on the calendar collection /home/bernard/calendar/,
between 9:00 AM and 5:00 PM on 2nd September 2004. The server
responds indicating three busy time intervals of one hour, two hours
and 30 minutes during the course of the time interval being examined.

>> Request <<

REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:free-busy-query xmlns:C="urn:ietf:params:xml:ns:caldav">
<C:time-range start="20040902T090000Z"
end="20040902T170000Z"/>
</C:free-busy-query>

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>> Response <<

HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:response>
<D:href>http://cal.example.com/home/bernard/calendar/</D:href>
<D:propstat>
<D:prop>
<C:calendar-data>BEGIN:VCALENDAR 200 OK
Date: Fri, 11 Nov 2005 09:32:12 GMT
Content-Type: text/calendar
Content-Length: xxxx

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VFREEBUSY
DTSTAMP:20050125T090000Z
DTSTART:20040902T090000Z
DTEND:20040902T170000Z
FREEBUSY;FBTYPE=BUSY-TENTATIVE:20040902T090000Z/PT1H
FREEBUSY:20040902T090000Z/PT1H,
20040902T120000Z/PT2H,
20040902T160000Z/PT30M
END:VFREEBUSY
END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>

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8. Guidelines

7.1.

8.1. Client-to-client Interoperability

There are a number of actions clients can take which will be legal
(the server will not return errors) but which can degrade
interoperability with other client implementations accessing the same
data. For example, a recurrence rule could be replaced with a set of
recurrence dates, a single recurring event could be replaced with a
set of independent resources to represent each recurrence, or the
start/end time values can be translated from the original timezone to
another timezone. Although these are this advice amounts to iCalendar
interoperability best practices and is not limited only to CalDAV
usage, interoperability problems are likely to be more evident in
CalDAV use cases.

7.2. Sychronization

8.2. Synchronization Operations

WebDAV already provides functionality required to synchronize a
collection or set of collections, make changes offline, and a simple
way to resolve conflicts when reconnected. Strong ETags are the key to
making this work, but these are not required of all WebDAV servers.
Since offline functionality is more important to Calendar calendar
applications than to some other WebDAV applications, CalDAV servers
MUST support strong ETags.

7.2.1. ETags as specified in Section 5.3.3.

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8.2.1. Use of Reports

7.2.1.1.

8.2.1.1. Restrict the Time Range

The reports REPORTs provided in CalDAV can be used by clients to optimize
their performance in terms of network bandwidth usage, and resource
consumption on the local client machine. Both of those issues are certainly major
considerations for mobile or handheld devices with limited capacity,
but they are also relevant to desktop client applications in cases
where the calendar collections contain large amounts of data.

Typically clients present calendar data to users in views that span a
finite time interval, so whenever possible clients should only
retrieve calendar items components from the server using CALDAV:calendar-query
report CALDAV:calendar-
query REPORT combined with a time-range CALDAV:time-range element to limit the scope
set of returned items components to just those needed to populate the
current view.

7.2.1.2.

8.2.1.2. Synchronize by Time Range

Typically in a calendar, historical data (events, to-dos etc. that
have completed prior to the current date) do not change, though they
may be deleted. As a result, a client can speed up the

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synchronization process by only considering data for the present time
and the future up to a reasonable limit (e.g., one week, one month).
If the user then tries to examine a portion of the calendar outside
of the range that has been synchronized, the client can perform
another synchronization operation on the new time interval being
examined. This "just-in-time" synchronization can minimize bandwidth
for common user interaction behaviors.

7.2.1.3.

8.2.1.3. Synchronization Process

If a client wants to support calendar data synchronization, as
opposed to downloading calendar data each time it is needed, it needs
to cache the component resources calendar object resource's URI and ETag along with the
actual calendar data. Whilst While the URI remains static for the lifetime
of the
component, calendar object resource, the ETag will change with each
successive change to the
component data. calendar object resource. Thus to
synchronize a local data cache with the server, the client can first
fetch the URI/ETag pairs for the time interval being considered, and
compare those results with the cached data. Any cached component
whose ETag differs from that on the server needs to be synchronized. refreshed.

In order to properly detect the changes between the server and client
data, the client will need to keep a record of which items calendar object
resources have been created, changed or deleted since the last
synchronization operation so that it can reconcile those changes with

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the data on the server.

Here's an example of how to do that would be the following: that:

The client issues a CALDAV:calendar-query REPORT request for a
specific time range, and asks for only the DAV:getetag property to be
returned:

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REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-query xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop>
<D:getetag/>
</D:prop>
<C:filter>
<C:comp-filter name="VCALENDAR">
<C:comp-filter name="VEVENT">
<C:time-range start="20040902T000000Z"
end="20040903T000000Z"/>
</C:comp-filter>
</C:comp-filter>
</C:filter>
</C:calendar-query>

The client then uses the results to determine which components calendar object
resources have changed, been created or deleted on the server and how
those relate to locally cached components calendar object resources that may
have changed, been created or deleted. If the client determines that
there are items calendar object resources on the server that need to be
fetched, the client issues a CALDAV:
calendar-multiget report CALDAV:calendar-multiget REPORT request
to fetch the actual their calendar data:

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REPORT /home/bernard/calendar/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: text/xml; application/xml; charset="utf-8"
Content-Length: xxxx

<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-multiget xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop>
<D:getetag/>
<C:calendar-data>
<C:comp name="VCALENDAR">
<C:allprop/>
<C:comp name="VEVENT">
<C:prop name="UID"/>
<C:prop name="DTSTART"/>
<C:prop name="DTEND"/>
<C:prop name="DURATION"/>
<C:prop name="EXDATE"/>
<C:prop name="EXRULE"/>
<C:prop name="RDATE"/>
<C:prop name="RRULE"/>
<C:prop name="LOCATION"/>
<C:prop name="SUMMARY"/>
</C:comp>
<C:comp name="VTIMEZONE">
<C:allprop/>
<C:allcomp/>
</C:comp>
</C:comp>
</C:calendar-data>
<C:calendar-data/>
</D:prop>
<D:href
>http://cal.example.com/home/bernard/calendar/evt1.ics</D:href>
<D:href
>http://cal.example.com/home/bernard/calendar/mtg1.ics</D:href>
<D:href>/home/bernard/calendar/evt1.ics</D:href>
<D:href>/home/bernard/calendar/mtg1.ics</D:href>
</C:calendar-multiget>

7.2.2.

8.2.2. Restrict the Properties Returned

Clients may not need all the calendar properties in of a calendar component object
resource when presenting information to the user. Since some
calendar property data values can be large (e.g., ATTACH or ATTENDEE lists) ATTENDEE)
clients can choose to ignore
those by only requesting the specific items it knows it will use,
through use of the CALDAV:calendar-data XML element in the relevant
reports.

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in a calendaring REPORT request to those it knows it will use.

However, if a client needs to make a change to a component, calendar object
resource, it can only change the entire component data calendar object resource via
a PUT request. There is currently no way to incrementally make a
change to a set of calendar properties within of a calendar component object resource.
As a result the client will have to
cache get the entire set of properties on a calendar object
resource that is being changed.

7.3.

8.3. Use of Locking

WebDAV locks can be used to prevent two clients modifying the same
resource from either overwriting each others' changes (though that
problem can also be solved by using ETags) and also to prevent the
user from or wasting time making
changes that will conflict with another set of changes. In a multi-user multi-
user calendar system, the an interactive calendar client could lock an
event while the user is editing the event, and unlock the event when
the user finishes or cancels. Locks can also be used to prevent
changes while data is being reorganized. For example, a calendar
client might lock two calendar collections prior to moving a bunch of
calendar resources from one to another.

Clients may request are responsible for requesting a lock timeout period that is
appropriate to the use case. When the user explicitly decides to
reserve a resource and prevent other changes, a long timeout might be

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appropriate, but in cases when the client automatically decides to
lock the resource the timeout should be short (and the client can
always refresh the lock should it need to). A short lock timeout
means that if the client is unable to remove the lock, the other
calendar users aren't prevented from making changes.

7.4.

8.4. Finding calendars

Much of the time a calendar client (or agent) will discover a new
calendar's location by being provided directly with the URL. E.g. a
user will type his or her own calendar location into client
configuration information, or cut copy and paste a URL from email into
the calendar application. The client need only confirm that the URL
points to a resource which is a calendar. calendar collection. The client may
also be able to browse WebDAV collections to find calendar
collections.

The choice of HTTP URLs means that calendar object resources are
backward compatible with existing software, but does have the
disadvantage that existing software does not usually know to look at
the OPTIONS response to that URL to determine what can be done with
it. This is somewhat of a barrier for WebDAV usage as well as with
CalDAV usage. This specification does not offer a way through this
other than making the information available in the OPTIONS response
should this be requested.

For calendar sharing and scheduling use cases, one might wish to find
the calendar belonging to another user. If the other user has a
calendar in the same repository, that calendar can be found by using
the principal namespace required by WebDAV ACL support. For other
cases, the authors have no universal solution but implementors can
consider whether to use vCard [RFC2426] or LDAP [RFC2251] standards
together with calendar attributes [RFC2739].

Because CalDAV requires servers to support WebDAV ACL [RFC3744]
including principal namespaces, and with the addition of the CALDAV:
calendar-home-set property, there are a couple options for CalDAV
clients to find one's own calendar or another user's calendar.

The DAV:principal-match REPORT is used to query the principal
namespace to find all principals for which a named property has a
value corresponding to the Principal-URL of the current user. A
request for the DAV:principal-match REPORT while specifying that the
DAV:principal-URL property must match the DAV:principal-URL of the
current user is in effect asking "who am I" or more exactly "what is
the identifier for the user authenticated in this request". The same
request can also include a DAV:prop element naming other properties
to return, so in one request asking for the CALDAV:calendar-home-set

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For calendar sharing

property, a WebDAV client can learn "who am I" and scheduling use cases, one might wish to "where are my
calendars". The REPORT request body looks like this:

<?xml version="1.0" encoding="utf-8" ?>
<D:principal-match xmlns:D="DAV:">
<D:principal-property>
<D:principal-URL/>
</D:principal-property>
<D:prop>
<C:calendar-home-set
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
</D:prop>
</D:principal-match>

To find
the calendar belonging to another user. If the other user has a
calendar in users calendars, the same repository, that calendar DAV:principal-property-search
REPORT can be found used to filter on some properties and return others.
To search for a calendar owned by using a user named "Laurie", the principal namespace required by WebDAV ACL support. For other
cases, REPORT
request body would look like this:

<?xml version="1.0" encoding="utf-8" ?>
<D:principal-property-search xmlns:D="DAV:">
<D:property-search>
<D:prop>
<D:displayname/>
</D:prop>
<D:match>Laurie</D:match>
</D:property-search>
<D:prop>
<C:calendar-home-set
xmlns:C="urn:ietf:params:xml:ns:caldav"/>
<D:displayname/>
</D:prop>
</D:principal-property-search>

The server performs a case-sensitive or caseless search for a
matching string subset of "Laurie" within the authors have no universal solution but implementors can
consider whether to use vCard [13] DAV:displayname
property. Thus, the server might return "Laurie Dusseault", "Laurier
Desruisseaux" or LDAP [12] standards together
with calendar attributes [14].

7.5. "Wilfrid Laurier" all as matching DAV:displayname
values, and the calendars for each of these.

8.5. Storing and Using Attachments

CalDAV clients MAY create attachments in calendar components either
as inline or external. This section contains some guidelines on
creating and managing attachments.

7.5.1.

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8.5.1. Inline attachments

CalDAV clients MUST support inline attachments as specified in the
iCalendar format. All [RFC2445]. CalDAV servers MUST support inline attachments,
so clients can rely on being able to create attachments this way. On
the other hand, inline attachments have some drawbacks:

o Servers MAY impose limitations on the size of iCalendar components calendar object
resources (i.e., refusing PUT requests of very large components). iCalendar
objects).

o Servers MAY impose storage quota limitations on calendar
collections [REF: WebDAV Quota] (See [I-D.ietf-webdav-quota]).

o Any change to a component calendar object resource containing an attachment
requires the entire attachment to be re-uploaded.

o Clients synchronizing a changed component calendar object resource have to
download the entire component calendar object resource even if the
attachment is unchanged.

7.5.2.

8.5.2. External attachments

CalDAV clients MUST support external attachments: if the client
access
accesses any calendar component object resource it MUST be capable of also
accessing the external attachment if one exists (subject to virus checking or
other security considerations). exists. An external
attachment could be:

o In a collection in the calendar collection containing the
component calendar
object resource;

o Somewhere else in the same repository that hosts the calendar
collection
collection; or

o On an HTTP of or FTP server elsewhere.

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CalDAV servers MAY provide support for child collections in calendar
collections. CalDAV servers MAY allow the MKCOL method to create sub-collections
inside
child collections in calendar collections. A sub-collection Child collections of a
calendar
collection MUST be able to collections MAY contain any kind type of resource, subject to
access and quota control. resource except calendar
collections which they MUST NOT contain. Some CalDAV servers won't
allow sub- child collections inside in calendar collections, and it may be
possible on such a server to discover other locations where
attachments can be stored.

Clients are entirely responsible for maintaining reference
consistency with calendar components that link to external
attachments. A client deleting a calendar component with an external

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attachment might therefore also delete the attachment if that's
appropriate, however appropriateness can be very hard to determine.
A new component might easily reference some pre-existing Web resource
which is intended to have independent existence from the CalDAV calendar
component (the "attachment" could be a major proposal to be discussed
in a meeting, for instance). Best practices will probably emerge and
should probably be documented but for now clients should be wary of
engaging in aggressive "cleanup" of external attachments. A client
could involve the user in making decisions about removing
unreferenced documents, or a client could be conservative in only
deleting attachments it had created.

Also, clients are responsible for consistency of permissions when
using external attachments. One reason for servers to support the
storage of attachments within sub-collections child collections of calendar
collections is that ACL inheritance might make it easier to grant the
same permissions to attachments that are granted on the calendar. calendar
collection. Otherwise, it can be very difficult to keep permissions
synchronized. With attachments stored on separate repositories, it
can be impossible to keep permissions consistent -- the two
repositories may not support the same permissions or have the same
set of principals. Some systems have used tickets or other anonymous
access control mechanisms to provide partially satisfactory solutions
to these kinds of problems.

7.6.

8.6. Storing and Using Alarms

Note that all CalDAV calendar collections (including those which the
user might treat as public or group calendars) can contain alarm
information on events and todos. to-dos. Users can synchronize a calendar
between multiple devices and decide to have alarms execute on a
different device than the device that created the alarm. Not all
VALARM
alarm action types are completely interoperable (e.g., those which
name a sound file to play).

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When an alarm has the action AUDIO, is "AUDIO", and the client is configured to
execute the alarm, the client SHOULD play the suggested sound if
it's available or play another sound, but SHOULD NOT rewrite the
alarm just to replace the suggested sound with a sound that's
locally available.

Similarly with

When the action DISPLAY, if a is "DISPLAY", and the client is configured to
execute the alarm then it alarm, the client SHOULD execute a display alarm by
displaying either according to the suggested description or some
reasonable replacement, but SHOULD NOT rewrite the alarm for its
own convenience.

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When an alarm has the action EMAIL, if is "EMAIL", and the client is incapable of sending
email, it SHOULD ignore the alarm but MUST continue to synchronize
the alarm itself.

This specification makes no recommendations about executing action alarm
of type PROCEDURE alarms except to note that clients are advised to take
care to avoid creating security holes by executing these.

Non-interoperable alarm information (e.g., should somebody define a
color to be used in a display alarm) should be put in custom non-standard
properties inside the VALARM component in order to keep the basic
alarm usable on all devices.

Clients that allow offline changes to a calendar object resources MUST
synchronize the alarm data that already exists in the calendar collection. resources.
Clients MAY execute alarms that are downloaded in this fashion,
possibly based on user preference. If a client is only doing read
operations on a calendar and there is no risk of losing alarm
information, then the client MAY discard alarm information.

This specification makes no attempt to provide multi-user alarms on
group calendars or to find out who an alarm is intended for.
Addressing those issues might require extensions to iCalendar, for
example to store alarms per-user or indicate which user a VALARM was
intended for. In the meantime, clients might maximize
interoperability by generally not uploading alarm information to
public, group or resource calendars.

9. XML Element Definitions

9.1. CALDAV:calendar XML Element

Name: calendar

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies the resource type of a calendar collection.

Description: See Section 4.2.

Definition:

<!ELEMENT calendar EMPTY>

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9.2. CALDAV:mkcalendar XML Element Definitions

8.1.

Name: mkcalendar

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies a request that lists the WebDAV property values to
be set for a calendar collection resource.

Description: See Section 5.3.1.

Definition:

<!ELEMENT mkcalendar (DAV:set)>

9.3. CALDAV:mkcalendar-response XML Element

Name: mkcalendar-response

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies a response body for a successful MKCALENDAR
request.

Description: See Section 5.3.1.

Definition:

<!ELEMENT mkcalendar-response ANY>

9.4. CALDAV:calendar-query XML Element

Name: calendar-query

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Defines a report REPORT for querying calendar data object resources.

Description: See Section 6.4. 7.6.

Definition:

<!ELEMENT calendar-query (DAV:allprop ((DAV:allprop |
DAV:propname | DAV:prop)?
filter>

8.2.
DAV:prop)?, filter, timezone?)>

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9.5. CALDAV:calendar-data XML Element

Name: calendar-data

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Used to define (1) specify a supported media type for calendar
object resources when nested in the CALDAV:supported-calendar-data
property; (2) specify which parts of a calendar component object resource
should be returned by a given calendaring REPORT; and (3) specify
the content of a calendar object resource in a response to a
calendaring REPORT.

Description: When nested in the CALDAV:supported-calendar-data
property, the CALDAV:calendar-data XML element specifies a media
type supported by the report that uses this element.

Description: CalDAV server for calendar object resources.

When used in a calendaring REPORT request, the CALDAV:calendar-data CALDAV:calendar-
data XML element specifies the iCalendar components and properties which parts of calendar object
resources need to be returned in the iCalendar objects part of the response. If this the CALDAV:
calendar-data XML element doesn't contain any CALDAV:comp element, iCalendar objects
calendar object resources will be returned with all in their components and properties.

Value: When entirety.

Finally, when used inside in a calendaring REPORT response, the CALDAV:calendar-data CALDAV:
calendar-data XML element
contains an iCalendar specifies the content of a calendar
object resource. Given that matched XML parsers normalizes the search filter two-
character sequence CRLF (US-ASCII decimal 13 and US-ASCII decimal
10) to a single LF character (US-ASCII decimal 10), the CR
character (US-ASCII decimal 13) MAY be omitted in calendar object
resources specified in the request. CALDAV:calendar-data XML element.
Furthermore, calendar object resources specified in the CALDAV:
calendar-data XML element MAY be invalid per their media type
specification if the CALDAV:calendar-data XML element part of the
calendaring REPORT request did not specify required properties
(e.g., UID, DTSTAMP, etc.) or specified a CALDAV:prop XML element
with the "novalue" attribute set to "yes".

Note: The CALDAV:calendar-data XML element is specified in requests
and responses inside the DAV:prop XML element as if it were a
WebDAV property. However, the CALDAV:calendar-data XML element is
not a WebDAV property and as such it is not returned in PROPFIND
responses nor used in PROPPATCH requests.

Definition:

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<!ELEMENT calendar-data ((comp?, (expand-recurrence-set (expand |
limit-recurrence-set)?)
limit-recurrence-set)?,
limit-freebusy-set?) |
#PCDATA)?>
PCDATA value: iCalendar object

<!ATTLIST calendar-data content-type CDATA "text/calendar">

<!ATTLIST calendar-data
version CDATA "2.0">

8.2.1.
content-type value: a MIME media type
version value: a version string

9.5.1. CALDAV:comp XML Element

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Name: comp

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Defines which component types to return return.

Description: The name value is a calendar component name (e.g.,
"VEVENT")

NOTE:
"VEVENT").

Definition:

<!ELEMENT comp (((allprop | prop*), allcomp) |
((allprop | prop*), comp*))>

<!ATTLIST comp name CDATA #REQUIRED>
name value: a calendar component name

Note: The CALDAV:prop and CALDAV:allprop elements used here have the same name
as the DAV:prop and DAV:allprop elements defined in WebDAV. [RFC2518].
However, the elements used
here have CALDAV:prop and CALDAV:allprop element are defined in
the "urn:ietf:params:xml:ns:caldav" namespace, as opposed
to namespace instead of the
"DAV:" namespace used for elements defined in WebDAV.

<!ELEMENT comp ((allcomp, (allprop | prop*)) |
(comp*, (allprop | prop*)))>

<!ATTLIST comp name CDATA #REQUIRED>

8.2.2. namespace.

9.5.2. CALDAV:allcomp XML Element

Name: allcomp

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies that all components shall be returned returned.

Description: This The CALDAV:allcomp XML element can be used when the
client wants all types of components returned by a report. calendaring
REPORT request.

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Definition:

<!ELEMENT allcomp EMPTY>

8.2.3.

9.5.3. CALDAV:allprop XML Element

Name: allprop

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies that all properties shall be returned.

Description: This The CALDAV:allprop XML element can be used when the
client wants all properties of components returned by a report.

NOTE:
calendaring REPORT request.

Definition:

<!ELEMENT allprop EMPTY>

Note: The CALDAV:allprop element defined here has the same name as the DAV:allprop
element defined in WebDAV. [RFC2518]. However, the CALDAV:
allprop CALDAV:allprop element
is defined here uses in the "urn:ietf:params:xml:ns:caldav"
namespace, as opposed to the "DAV:" namespace used for
instead of the DAV:

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allprop element defined in WebDAV.

<!ELEMENT allprop EMPTY>

8.2.4. "DAV:" namespace.

9.5.4. CALDAV:prop XML Element

Name: prop

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Defines which properties to return in the response.

Description: The "name" attribute specifies the name of the calendar
property to return (e.g., "ATTENDEE"). The "novalue" attribute
can be used by clients to request that the actual value of the
property not be returned (if the "novalue" attribute is set to
"yes"). In that case the server will return just the iCalendar
property name and any iCalendar parameters and a trailing ":"
without the subsequent value data.

NOTE:

Definition:

<!ELEMENT prop EMPTY>

<!ATTLIST prop name CDATA #REQUIRED
novalue (yes | no) "no">
name value: a calendar property name

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novalue value: "yes" or "no"

Note: The CALDAV:prop element defined here has the same name as the DAV:prop
element defined in WebDAV. [RFC2518]. However, the CALDAV:prop element is
defined here uses in the "urn:ietf:params:xml:ns:caldav" namespace, as
opposed to namespace instead
of the "DAV:" namespace used namespace.

9.5.5. CALDAV:expand XML Element

Name: expand

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Forces the server to expand recurring components into
individual recurrence instances.

Description: The CALDAV:expand XML element specifies that for a given
calendaring REPORT request the server MUST expand the recurrence
set into calendar components that define exactly one recurrence
instance and MUST return only those whose scheduled time intersect
a specified time range. The "start" attribute specifies the
inclusive start of the time range, and the "end" attribute
specifies the non-inclusive end of the time range. Both
attributes are specified as date with UTC time value. The server
MUST use the same logic as defined for CALDAV:time-range to
determine if a recurrence instance intersects the DAV:prop element defined
in WebDAV. specified time
range. The returned calendar components MUST NOT use recurrence
properties (i.e., EXDATE, EXRULE, RDATE and RRULE) and MUST NOT
have reference to or include VTIMEZONE components. Date and local
time with reference to time zone information MUST be converted
into date with UTC time.

Definition:

<!ELEMENT prop expand EMPTY>

<!ATTLIST prop name expand start CDATA #REQUIRED
novalue (yes|no) "no">

8.2.5. CALDAV:expand-recurrence-set
end CDATA #REQUIRED>
start value: an iCalendar "date with UTC time"
end value: an iCalendar "date with UTC time"

9.5.6. CALDAV:limit-recurrence-set XML Element

Name: expand-recurrence-set limit-recurrence-set

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Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Forces the server Specifies a time range to expand recurring components into
separate instances. limit the set of "overridden
components" returned by the server.

Description: The CALDAV:expand-recurrence-set CALDAV:limit-recurrence-set XML element specifies
that
recurring components shall be returned for a given calendaring REPORT request the server MUST only
return the "master component" as individual components
with no well as the "overridden
components" that specify one or more recurrence properties (i.e., EXDATE, EXRULE, RDATE and
RRULE). instances whose
current scheduled time or original scheduled time intersect a
specified time range. The required "start" attribute specifies the
inclusive start of the time range, and the "end" attribute
specifies the non-inclusive end of the time range. Both
attributes contain
iCalendar format DATE-TIME (always are specified in UTC) as date with UTC time value. The server
MUST use the same logic as defined for CALDAV:time-range to
determine if the current or DATE
values original scheduled time of an
"overridden" recurrence instance intersect the specified time
range. Overridden components that define have a RANGE parameter on their
RECURRENCE-ID property may specify one or more instances in the
recurrence set, and some of those instances may fall within the
specified time interval over which range, or may have originally fallen within the recurrence
expansion should take place. The start value
specified time range prior to being overridden. If that is inclusive and the
end value is exclusive of
case, the interval as per iCalendar DTSTART

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and DTEND properties. The server overridden component MUST return only those expanded
components whose time interval intersects be included in the interval specified
by results as
it has a direct impact on the start and end attributes. interpretation of instances within
the specified time range.

Definition:

<!ELEMENT expand-recurrence-set limit-recurrence-set EMPTY>

<!ATTLIST expand-recurrence-set limit-recurrence-set start CDATA #REQUIRED
end CDATA #REQUIRED>

8.2.6. CALDAV:limit-recurrence-set
start value: an iCalendar "date with UTC time"
end value: an iCalendar "date with UTC time"

9.5.7. CALDAV:limit-freebusy-set XML Element

Name: limit-recurrence-set limit-freebusy-set

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies a time range to limit the set of recurrence
instances FREEBUSY values
returned by the server.

Description: The CALDAV:limit-recurrence-set CALDAV:limit-freebusy-set XML element specifies that
for a given calendaring REPORT request the server MUST only return information about
the recurrence
instances whose scheduled time FREEBUSY property values of a VFREEBUSY component that
intersect a specified time range
for a given calendaring REPORT request. range. The required "start" attribute specifies

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the inclusive start of the time range, and the "end" attributes specify DATE or DATE-TIME iCalendar values in UTC
that defines attribute
specifies the non-inclusive end of the actual time range. Both
attributes are specified as "date with UTC time" value. The
server MUST use the same logic as defined for CALDAV:time-range to
determine if a
recurrence instance FREEBUSY property value intersect a given the specified
time range.

Definition:

<!ELEMENT limit-recurrence-set limit-freebusy-set EMPTY>

<!ATTLIST limit-recurrence-set limit-freebusy-set start CDATA #REQUIRED
end CDATA #REQUIRED>

8.3.
start value: an iCalendar "date with UTC time"
end value: an iCalendar "date with UTC time"

9.6. CALDAV:filter XML Element

Name: filter

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Determines which matching Specifies a filter to limit the set of calendar components are returned.
returned by the server.

Description: The "filter" CALDAV:filter XML element specifies the search
filter used to
match limit the calendar components that should be returned by a report.
calendaring REPORT request.

Definition:

<!ELEMENT filter comp-filter>

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8.3.1. (comp-filter)>

9.6.1. CALDAV:comp-filter XML Element

Name: comp-filter

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Limits the Specifies search to only the chosen component types. criteria on calendar components.

Description: The "name" attribute is a CALDAV:comp-filter XML element specifies the queried
calendar component type (e.g., "VEVENT"). When this element A calendar object
resource is present, the server should only
return said to match a component CALDAV:comp-filter if it matches contains
calendar components of the filter, which is type specified by the "name" attribute,
and that it contains at least one recurrence instance scheduled to say:

("no is-defined element" OR "is-defined matches") AND
("no time-range element" OR "time-range matches") AND
("no sub-component filter" OR "all sub-component filters match") AND
("no property filter elements" OR "all property filters match")
overlap a given time range if a CALDAV:time-range XML element is
specified, and that any CALDAV:prop-filter and CALDAV:comp-filter

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child elements also matches.

Definition:

<!ELEMENT comp-filter (is-defined | time-range)?
comp-filter* prop-filter*> (time-range?, prop-filter*,
comp-filter*)>

<!ATTLIST comp-filter name CDATA #REQUIRED>

8.3.2.
name value: a calendar component name (e.g., "VEVENT")

9.6.2. CALDAV:prop-filter XML Element

Name: prop-filter

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Limits the Specifies search to specific criteria on calendar properties.

Description: The "name" attribute MUST contain an iCalendar CALDAV:prop-filter XML element specifies a search
criteria on a specific calendar property
name (e.g., "ATTENDEE"). When CATEGORIES) in the CALDAV:prop-filter executes,
scope of a given CALDAV:comp-filter. A calendar component is said
to match a CALDAV:prop-filter if it defines the property specified
by the "name" attribute, and that it matches if:

("no is-defined element" OR "is-defined matches") AND
("no time-range element" OR "time-range matches") AND
("no text match element" OR "text-match matches") AND
("no parameter filter elements" OR "all parameter filters match") the CALDAV:time-range
or CALDAV:text-match conditions if specified, and that any CALDAV:
param-filter child elements also matches.

Definition:

<!ELEMENT prop-filter (is-defined ((time-range | time-range | text-match)?
param-filter*> text-match)?,
param-filter*)>

<!ATTLIST prop-filter name CDATA #REQUIRED>

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8.3.3.
name value: a calendar property name (e.g., "ATTENDEE")

9.6.3. CALDAV:param-filter XML Element

Name: param-filter

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Limits the search to specific parameters. parameter values.

Description: The "param-filter" CALDAV:param-filter XML element limits the specifies a search result to
criteria on a specific calendar property parameter (e.g.,
PARTSTAT) in the set scope of resources containing properties with parameters that
meet the parameter filter rules. When this filter executes, a given CALDAV:prop-filter. A calendar
property is said to match a CALDAV:param-filter if it defines the
parameter specified by the "name" attribute, and that it matches if:

("is-defined matches" OR "text-match matches")
the CALDAV:text-match condition if specified.

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Definition:

<!ELEMENT param-filter (is-defined | text-match) > (text-match?)>

<!ATTLIST param-filter name CDATA #REQUIRED>

8.3.4. CALDAV:is-defined XML Element

Name: is-defined

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Causes a search to match a resource if
name value: a component type, property or parameter name exists.

Description: The CALDAV:is-defined XML element limits the filter to
resources where the named component, property or parameter is
defined.

<!ELEMENT is-defined EMPTY>

8.3.5. (e.g., "PARTSTAT")

9.6.4. CALDAV:text-match XML Element

Name: text-match

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies a substring match on a property or parameter
value.

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Description: The specified CALDAV:text-match XML element specifies text is used
for a substring match against the property or parameter value
specified in a report. calendaring REPORT request. The "caseless"
attribute indicates whether the match is case-sensitive (value set
to "no") or case-insensitive (value set to "yes"). The default
value is server-specified. Caseless matching SHOULD be
implemented as defined in section 5.18 of the Unicode Standard
([11]).
([UNICODE4]). Support for the "caseless" attribute is optional.
A server should respond with a status of 422 if it is used but
cannot be supported.

Definition:

<!ELEMENT text-match #PCDATA> (#PCDATA)>
PCDATA value: string

<!ATTLIST text-match caseless (yes|no)>

8.4. CALDAV:time-range (yes | no) #IMPLIED>

9.7. CALDAV:timezone XML Element

Name: time-range timezone

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies a the time interval for testing components against. zone component...

Description: The CALDAV:time-range CALDAV:timezone XML element allows specifies that for a single time
range
given calendaring REPORT request the server MUST rely on the
specified VTIMEZONE component instead of the CALDAV:calendar-
timezone property of the calendar collection in which the calendar
object resource is contained to be defined, resolve "date" values and "date
with local time" values (i.e., floating time) to "date with UTC

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time" values. The server will require this information to
determine if a calendar component scheduled with "date" values or
"date with local time" values intersect a CALDAV:time-range
specified in order a CALDAV:calendar-query REPORT.

Definition:

<!ELEMENT timezone (#PCDATA)>
PCDATA value: an iCalendar object with exactly one VTIMEZONE

9.8. CALDAV:time-range XML Element

Name: time-range

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: Specifies a time range to limit all the results set of calendar
components returned by the
search to server.

Description: The CALDAV:time-range XML element specifies that for a
given calendaring REPORT request the set of server MUST only return the
calendar object resources that contain that, depending on the context, have a
component which
overlap that or property or parameter whose value intersect a
specified time range. The value "start" attribute specifies the
inclusive start of the "start" time range, and the "end"
attributes MUST follow attribute
specifies the syntax non-inclusive end of the DATE or DATE-TIME
iCalendar value type, with any time range. Both
attributes are specified in UTC. as "date with UTC time" value. While the
"start" and "end" attributes are not required to allow time ranges
opened at one end, at least one of them MUST be specified in the
CALDAV:time-range element.

[[Comment.1: We need to clarify the logic when the DTSTART, DTEND,
DURATION, or DUE properties are not defined in the calendar
component. --desruisseaux]]

A VEVENT component overlaps a given time-range time range if:

(DTSTART <= start AND DTEND > start) OR
(DTSTART <= start AND DTSTART+DURATION > start) OR
(DTSTART >= start AND DTSTART < end) OR
(DTEND > start AND DTEND <= end)

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A VEVENT component with no DTSTART and DTEND properties does not
overlap any time range.

A VTODO component overlaps a given time-range time range if:

(DTSTART <= start AND DUE >= start) OR
(DTSTART <= start AND DTSTART+DURATION > start) OR
(DTSTART >= start AND DTSTART < end) OR
(DUE >= start AND DUE < end)

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A VTODO component with no DTSTART and DUE properties does not
overlap any time range.

A VJOURNAL component overlaps a given time-range time range if:

DTSTART >= start AND DTSTART < end

A VJOURNAL component with no DTSTART property does not overlap any
time range.

A VFREEBUSY component overlaps a given time range if for any of
its FREEBUSY property value the following condition holds:

freebusy-period-start >= start AND freebusy-period-end < end

A VFREEBUSY component with no FREEBUSY property does not overlap
any time range.

A VALARM component overlaps a given time-range time range if:

trigger-time >= start AND trigger-time < end

Any property

A VALARM component can be defined such that it triggers
repeatedly. Such a VALARM component is said to overlap a given
time range if at least one of value type DATE-TIME or DATE (e.g., DTSTAMP) will
match its trigger overlap the time range.

The calendar properties COMPLETED, CREATED, DTSTAMP and LAST-
MODIFIED overlaps a given time-range if:

value time range

date-time >= start AND value date-time < end

The semantic of CALDAV:time-range is not defined for any other
calendar properties.

Definition:

<!ELEMENT time-range EMPTY>

<!ATTLIST time-range start CDATA #IMPLIED
end CDATA>

8.5. CDATA #IMPLIED>
start value: an iCalendar "date with UTC time"
end value: an iCalendar "date with UTC time"

9.9. CALDAV:calendar-multiget XML Element

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Name: calendar-multiget

Namespace: urn:ietf:params:xml:ns:caldav

Purpose: CalDAV report REPORT used to retrieve specific calendar component
items via their URIs. object
resources.

Description: See Section 6.5. 7.7.

Definition:

<!ELEMENT calendar-multiget (DAV:allprop ((DAV:allprop |
DAV:propname | DAV:prop)?
DAV:href+>

8.6.
DAV:prop)?, DAV:href+)>

9.10. CALDAV:free-busy-query XML Element

Name: free-busy-query

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Namespace: urn:ietf:params:xml:ns:caldav

Purpose: CalDAV report REPORT used to generate a VFREEBUSY to determine busy
time over a specific set of time ranges. range.

Description: See Section 6.6. 7.8.

Definition:

<!ELEMENT free-busy-query time-range+ >

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9. (time-range)>

10. Internationalization Considerations

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CalDAV September 2005

10. allows internationalized strings to be stored and retrieved
for the description of calendar collections (see Section 5.2.1).

11. Security Considerations

HTTP protocol transactions are sent in the clear over the network
unless protection from snooping is negotiated. This can be
accomplished by use of TLS as defined in RFC2818 [6]. [RFC2818]. In particular,
HTTP Basic authentication MUST NOT be used unless TLS is in effect.

Servers MUST take adequate precautions to ensure malicious clients
cannot consume excessive server resources (CPU, memory, disk, etc.)
through carefully crafted reports. For example, a client could
upload an event with a recurrence rule that specifies a recurring

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event occurring every second for the next 100 years which would
result in approximately 3 x 10^9 instances! A report REPORT that asks for
recurrences to be expanded over that range would likely constitute a
denial-of-service attack on the server.

[[Comment.2: We should make an explicit reference

Security considerations described in iCalendar [RFC2445] and iTIP
[RFC2446] are also applicable to the CalDAV.

Beyond these, CalDAV does not raise any security considerations mentionned that
are not present in iCalendar, iTIP HTTP [RFC2616] and iMIP.
--desruisseaux]]

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11. WebDAV [RFC2518], [RFC3253],
[RFC3744], as discussed in those documents.

12. IANA Consideration

In addition to the namespaces defined by RFC2518 [4] for XML
elements, this

This document uses a one new URN to describe identify a new XML namespace
conforming namespace. The
URN conforms to a registry mechanism described in RFC3688 [8]. All
other IANA considerations mentioned in RFC2518 [4] also apply to this
document.

11.1. [RFC3688].

12.1. Namespace Registration

Registration request for the CalDAV namespace:

URI: urn:ietf:params:xml:ns:caldav

Registrant Contact: See the "Author's Address" section of this
document.

XML: None. Namespace URIs do not represent an XML specification.

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12.

13. Acknowledgements

The authors would like to thank the following individuals for
contributing their ideas and support for writing this specification:
Michael Arick, Mario Bonin, Chris Bryant, Scott Carr, Mike Douglass,
Helge Hess, Dan Mosedale, Kervin L. Pierre, Julian F. Reschke, Mike
Shaver, Simon Vaillancourt, Wilfredo Sanchez Vega 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.

14. References

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13. References

13.1.

14.1. Normative References

[1]

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[2]

[RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, January 1999.

[3]

[RFC2445] Dawson, F. and Stenerson, D., "Internet Calendaring and
Scheduling Core Object Specification (iCalendar)",
RFC 2445, November 1998.

[4]

[RFC2446] Silverberg, S., Mansour, S., Dawson, F., and R. Hopson,
"iCalendar Transport-Independent Interoperability Protocol
(iTIP) Scheduling Events, BusyTime, To-dos and Journal
Entries", RFC 2446, November 1998.

[RFC2518] Goland, Y., Whitehead, E., Faizi, A., Carter, S., and D.
Jensen, "HTTP Extensions for Distributed Authoring --
WEBDAV", RFC 2518, February 1999.

[5]

[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.

[6]

[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

[7]

[RFC3253] Clemm, G., Amsden, J., Ellison, T., Kaler, C., and J.
Whitehead, "Versioning Extensions to WebDAV (Web
Distributed Authoring and Versioning)", RFC 3253,
March 2002.

[8]

[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.

[9]

[RFC3744] Clemm, G., Reschke, J., Sedlar, E., and J. Whitehead, "Web
Distributed Authoring and Versioning (WebDAV) Access
Control Protocol", RFC 3744, May 2004.

[10] Bray, T.,

[UNICODE4]
The Unicode Consortium, "The Unicode Standard, Version
4.0", Addison-Wesley, Boston, MA. ISBN 0-321-18578-1,
August 2003,
<http://www.unicode.org/versions/Unicode4.0.0/>.

[W3C.REC-xml-20040204]
Yergeau, F., Paoli, J., Sperberg-McQueen, C., Maler, E., Bray, T.,
and F.
Yergeau, E. Maler, "Extensible Markup Language (XML) 1.0 (Third
Edition)", W3C REC-xml-20040204, February 2004,
<http://www.w3.org/TR/2004/REC-xml-20040204>.

[11] The Unicode Consortium, "The Unicode Standard - Version 4.0",
Addison-Wesley , August 2003,
<http://www.unicode.org/versions/Unicode4.0.0/>.

ISBN 0321185781

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13.2.

Edition)", W3C REC REC-xml-20040204, February 2004.

14.2. Informative References

[12]

[I-D.ietf-webdav-quota]
Korver, B. and L. Dusseault, "Quota and Size Properties
for DAV Collections", draft-ietf-webdav-quota-07 (work in
progress), April 2005.

[RFC2251] Wahl, M., Howes, T., and S. Kille, "Lightweight Directory
Access Protocol (v3)", RFC 2251, December 1997.

[13]

[RFC2426] Dawson, F. and T. Howes, "vCard MIME Directory Profile",
RFC 2426, September 1998.

[14]

[RFC2739] Small, T., Hennessy, D., and F. Dawson, "Calendar
Attributes for vCard and LDAP", RFC 2739, January 2000.

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Appendix A. CalDAV Method Privilege Table (Normative)

The following table extend extends the WebDAV Method Privilege Table
specified in Appendix B of WebDAV ACL [9]. [RFC3744].

Appendix B. Calendar collections used in the examples

This appendix shows the calendar object resources contained in the
calendar collections queried in the examples throughout this
document.

The content of each calendar collection is being shown as it would be
returned to the following CALDAV:calendar-query REPORT request:

[TBD]

Appendix C. Changes

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C.1. Changes in -09

a. Numerous editorial changes.

b. Removed the CALDAV:is-defined XML element.

c. Removed section on privilege aggregation.

d. Renamed the CALDAV:expand-recurrence-set XML element to CALDAV:
expand and clarified the server behavior.

e. Renamed the CALDAV:calendar-component-restriction-set XML
element to CALDAV:supported-calendar-component-set.

f. Renamed the CALDAV:calendar-restrictions XML element to CALDAV:
supported-calendar-data.

g. Renamed some preconditions as "success conditions" instead of
"failure causes". For instance, the precondition CALDAV:
calendar-collection-location-bad has been renamed to CALDAV:
calendar-collection-location-ok.

h. Reordered some sections.

i. Clarified the definition of CALDAV:time-range to specify that a
repeating VALARM component is said to intersect a given time
range if at least one of its trigger intersect the time range.

j. Clarified that calendar object resources stored in calendar
collections MUST NOT specify the iCalendar METHOD property.

k. Clarified that CALDAV:calendar-data XML element is not a WebDAV
property even though it is specified in the DAV:prop XML element
in both calendaring REPORT requests and responses.

l. Clarified CALDAV:limit-recurrence-set with respect to the RANGE
parameter on the RECURRENCE-ID property.

m. Changed the CALDAV:free-busy-query XML element to contain
exactly one CALDAV:time-range XML element.

n. Changed many ELEMENT and ATTLIST declarations to comply with DTD
syntax.

o. Changed XML element CALDAV:calendar-query to allow new XML
element CALDAV:timezone.

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Appendix B. Changes

B.1.

p. Changed the XML elements CALDAV:time-range, CALDAV:expand and
CALDAV:limit-recurrence-set to only allow DATE-TIME with UTC
time values for the "start" and "end" attributes.

q. Changed description of CALDAV:limit-recurrence-set to specify
that re-scheduled "overridden" recurrence instances whose
original scheduled time used to overlap the time range specified
by the "start" and "end" attribute should always be returned in
a REPORT response.

r. Changed the description of the value of CALDAV:calendar-data XML
element to specify that the CR character (US-ASCII decimal 13)
MAY be omitted in the iCalendar object specified in this XML
element.

s. Added specific requirements for entity tags support.

t. Added more preconditions.

u. Added further guidelines about finding calendars.

v. Added XML element CALDAV:limit-freebusy-set to limit the set of
FREEBUSY property values returned in VFREEBUSY components.

w. Added property CALDAV:calendar-timezone on calendar collections.

x. Added XML element CALDAV:timezone to override the CALDAV:
calendar-timezone property for a given CALDAV:calendar-query
REPORT request.

y. Added text on the conversion of "floating date" and "floating
time" values to date with UTC time values.

z. Completed internationalization considerations section.

aa. Completed security considerations section.

C.2. Changes in -08

a. Removed statement that said that client SHOULD always request
DAV:getetag in calendar REPORTs.

b. Removed redefiniton of DAV:response.

c. Removed XML elements CALDAV:calendar-data-only.

d. Removed resource type CALDAV:calendar-home.

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e. Moved the CALDAV:calendar-data element in the DAV:prop element in
requests, and in the DAV:propstat element in responses.

f. Further defined the request body of MKCALENDAR to allow clients
to set properties at calendar collection creation time.

g. Renamed CALDAV:calendar-home-URL to CALDAV:calendar-home-set

h. Clarified the fact that calendar collections may only contain
calendar object resources and ordinary collections.

i. Clarified that calendar REPORTs should only be applied to
calendar object resources contained in calendar collections.

j. Changed the CALDAV:calendar-component-restriction-set and CALDAV:
calendar-restriction properties to always be protected.

k. Changed to use existing postcondition DAV:needs-privileges
instead of a new CALDAV:insufficient-privilege postcondition.

l. Added example for limit-recurrence-set.

m. Added example for expand-recurrence-set.

n. Moved CALDAV:calendar-address-set in the calendar-schedule draft
and renamed it to CALDAV:calendar-user-address-set.

o. Added guidelines on attachments and alarms.

B.2.

C.3. Changes in -07

a. Various editorial changes.

b. Added properties calendar-restrictions and calendar-component-
restriction-set on calendar collections.

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c. Added properties calendar-home-URL and calendar-address-set on
principal resources.

d. Removed property calendar-URL on principal resources.

e. Added pre- and postconditions to reports.

f. Added new XML elements calendar-data-only and limit-recurrent-
set.

g. Modified calendar-data XML element to support the attributes
content-type and version.

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h. Reorganised sections 3, 4, 5 & 6 into two sections and re-ordered
sub-sections.

i. Added comment about client not setting a duplicate displayname.

j. Removed three CalDAV OPTIONS requests.

k. Changed "authenticated user" to "user" in various places.

l. Rewrote section on calendar object resource restrictions for
better clarity.

B.3.

C.4. Changes in -06

a. Reworded section "Recurrence and the Data Model".

b. Removed timezone collection feature.

c. Removed ability for a server to return the Location header on a
successful PUT request.

d. Clarified restrictions on calendar object resources contained in
calendar collections.

e. Added preconditions on PUT in calendar collections.

f. Added informative "Guidelines" section, with information on
locking and how to find calendar collections.

g. Moved "Sychronization Operations" section in the "Guidelines"
section.

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B.4.

C.5. Changes in -05

a. Removed a lot of non-normative text.

b. Removed property promotion/demotion requirements.

c. Removed calendar-owner and cal-scale properties.

d. Removed 'ical' prefix/text from element names.

e. Relaxed WebDAV Class 2 (locking) requirement to a MAY.

f. Relaxed MKCALENDAR requirement to a SHOULD.

g. Moved the XML Namespace section in the Introduction.

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h. Added CALDAV: prefix to CalDAV XML elements in the text.

i. Added CALDAV:calendar-multiget report.

j. Added CALDAV:free-busy-query report.

k. Added CALDAV:calendar-description property.

l. Changed CALDAV:calendar-query-result element name to CALDAV:
calendar-data

m. Added description and examples of handling timezones.

n. Added mandatory "start" and "end" attributes to the CALDAV:
expand-recurrence-set element.

o. Added three CalDAV OPTIONS requests.

p. Grouped XML Element declarations in a separate section.

B.5.

C.6. Changes in -04

a. Added a note about the HTTP Location response header.

b. Added report calendar-query.

c. Removed reports calendar-property-search and calendar-time-range.

d. Removed section on CalDAV and timezones.

e. Added requirement to return ETag on creation.

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f. Revised data model to remove sub-collections from calendar
collection.

g. Added informative references section.

h. Removed dependencies on DASL.

B.6.

C.7. Changes in -03

a. Removed Calendar Containers (simplification that doesn't seem to
remove much functionality)

b. Added MKCALENDAR to create calendars and all sub-collections

c. Added cal-scale property to calendars

B.7.

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C.8. Changes in -02

Basically still adding major sections of content:

a. Defined new field values to the OPTIONS "DAV:" response header

b. Added new resource properties

c. Added new principal properties

d. Added new SCHEDULE method and related headers

e. Added new privileges for scheduling

B.8.

C.9. Changes in -01

a. Added section on privileges for calendaring, extending WebDAV ACL
privilege set

b. Defined what to do with unrecognized properties in the bodies of
iCalendar events, with respect to property promotion/demotion

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Authors' Addresses

Cyrus Daboo
ISAMET Inc.
5001 Baum Blvd.
Suite 650
Pittsburgh, PA 15213
US

Email: daboo@isamet.com
URI: http://www.isamet.com/ cyrus@daboo.name

Bernard Desruisseaux
Oracle Corporation
600 Blvd. de Maisonneuve West
Suite 1900
Montreal, QC H3A 3J2
CA

Email: bernard.desruisseaux@oracle.com
URI: http://www.oracle.com/

Lisa Dusseault
Open Source Application Foundation
2064 Edgewood Dr.
Palo Alto, CA 94303
US

Email: lisa@osafoundation.org
URI: http://www.osafoundation.org/

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Acknowledgment

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