Calendaring Extensions to WebDAV (CalDAV)ISAMET Inc.5001 Baum Blvd.Suite 650PittsburghPA15213USdaboo@isamet.comhttp://www.isamet.com/Oracle Corporation600 Blvd. de Maisonneuve West10th FloorMontrealQCH3A 3J2CAbernard.desruisseaux@oracle.comhttp://www.oracle.com/Open Source Application
Foundation2064 Edgewood Dr.Palo AltoCA94303USlisa@osafoundation.orghttp://www.osafoundation.org/
Applications
calschedcalschcaldavcalendarcalendaringschedulingwebdaviCaliCalendartext/calendarHTTP
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 single-user calendar access, calendar sharing, and
calendar publishing.
The concept of using HTTP and
WebDAV as a basis for a
calendaring server 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 using HTTP PUT/GET to upload and download
iCalendar 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 is therefore intended to propose a standard way of
modeling calendar data in WebDAV, plus some additional features
to make calendar access work well. Discussion of this Internet-Draft is being done on the mailing list
<http://lists.osafoundation.org/mailman/listinfo/ietf-caldav>.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 .
The namespace "urn:ietf:params:xml:ns:caldav" is reserved for
the XML elements defined in this specification, or in other
Standards Track IETF RFCs written to extend CalDAV.
It MUST NOT be used for proprietary extensions.Note that the XML declarations used in this document are
incomplete, in that they do not include namespace information.
Thus, the reader MUST NOT use these declarations as the only
way to create valid CalDAV properties or to validate
CalDAV XML element type. Some of the declarations refer to XML
elements defined by WebDAV which use the "DAV:" namespace.
Wherever such elements appear, they are explicitly given the
"DAV:" prefix to help avoid confusion.Also note that some CalDAV XML element names are identiqual to
WebDAV XML element names, though their namespace differs. Care
MUST be taken not to confuse the two sets of names.The augmented BNF used by this document to describe protocol
elements is described in Section 2.1 of . Because this augmented BNF uses the
basic production rules provided in Section 2.2 of , 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 .When XML element types in the namespaces "DAV:" and
"urn:ietf:params:xml:ns:caldav" are referenced in this
document outside of the context of an XML fragment,
the string "DAV:" and "CALDAV:" will be prefixed to
the element types respectively.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.This section lists what functionality is required of a CalDAV
server. To advertise support for CalDAV, a server:
MUST support WebDAV Class 1.MUST support WebDAV ACL with
the privilege defined in of
this document.MUST support SSL.MUST support strong ETags to support disconnected operations.MUST support all required calendaring REPORTs defined in this
document.MUST advertise calendaring REPORTs via the
DAV:supported-report-set property as defined in
DeltaV.In addition, a server:
SHOULD support MKCALENDAR.MAY support WebDAV Class 2 (i.e., locking).
CalDAV should provide some guidelines to use locking
in the context of calendaring applications.
MAY support WebDAV DeltaV
or some of its components.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 attempts
to follow the same pattern by developing all new features based
on a well-described data model. In the CalDAV data model, every iCalendar VEVENT, VJOURNAL,
VTODO and VFREEBUSY component is stored as an individual
HTTP/WebDAV resource. That means each calendar resource may be
individually locked and have individual WebDAV properties.
These resources are placed into WebDAV collections with a
mostly-fixed structure.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://example.org/webdav/" may
contain WebDAV collections and resources, all of which have
URLs beginning with "http://example.org/webdav/". Note that
the root URL "http://example.org/" 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 areas,
and non-calendaring data in other areas.A WebDAV repository may advertise itself as a CalDAV server
if it 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
/lisa/calendar/ as well as in /bernard/calendar/,
and non-calendar data in /lisa/contacts/). Or, it might
mean that calendar data can be found only in certain sections of
the repository (e.g., /calendars/user/). Calendaring
features are only required in the repository sections that
are or contain calendaring objects. So a repository
confining calendar data to the /caldav/ 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 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 calendars may be shared
and accessible via multiple clients. HTTP ETags and other
tools help this work.Recurrence is an important part of the data model because it
governs how many resources are expected to exist. Consider the outcome if recurrence were handled through the
creation of many nearly-identical WebDAV resources. With
this model, it becomes hard to keep synchronized data
consistent. Even worse, some features like LOCK become
difficult -- it's hard to lock the right set of resources
so that the user can change the title of all recurrences of
an appointment. Due to these considerations, this proposal
does not model recurrences as separate resources. Instead, this proposal models recurrence patterns as
properties of calendar resources. This makes for much less
data to synchronize, and makes it easier to make changes to
all recurrences or to a recurrence pattern. It makes it
easier to create a recurring component, and easier to
delete all recurrences. The drawback of the recurrence-is-a-property approach is
that it becomes harder to see what events occur in a given
time interval. It's a very common function for calendar views
to display all events happening between midnight yesterday
and midnight tonight, or all events happening within one
week. In these views, each recurrence appears as if it were
an individual appointment. The CALDAV:calendar-query REPORT
defined in this document make these views possible.Because of this choice, clients MUST NOT create separate
resources to represent a recurring event when the
recurrence pattern is known. Otherwise, it makes it more
difficult for other clients to interoperate and modify the
recurring event. Most importantly, clients MUST NOT
duplicate events represented through recurrence patterns
with manually created events, which would appear as
duplicates to the server and to other clients. Calendar resources in CalDAV MUST be valid iCalendar
objects. As such, an individual VTIMEZONE calendar
component MUST be specified for each unique TZID
parameter value specified in an iCalendar object.
Unfortunately this mean that the same VTIMEZONE
component will get sent or retrieved multiple times
for each iCalendar object that uses the timezone.
This is not efficient in terms of bandwidth usage.
Not clear how big an issue that really is.
CalDAV already allows clients to retrieve iCalendar
objects without their VTIMEZONE component with the
CALDAV:calendar-query REPORT. It is still not clear
whether a client could rely only on the value of
the TZID parameter, or should it always requests a
VTIMEZONE component with at least the TZID and
TZURL properties and rely on the TZURL as a unique
identifier for a given time zone.
CalDAV servers have no choice but to return complete
VTIMEZONE components in iCalendar object retrieve
with the GET method as their is no way to know if
the client is a CalDAV client or a simple HTTP
client.
On a PUT request perhaps a CalDAV server could
accept an iCalendar object with a VTIMEZONE
object that has at least TZURL that points to a
calendar resource that defines a time zone
on the server.
The timezone collection is a calendar collection that
contains only VTIMEZONE components as separate resources
within that collection. There MUST be only one VTIMEZONE
component per calendar resource in the timezone collection.
Clients can discover the location of the timezone
collection with the CALDAV:timezone-collection-set
OPTIONS request
(see )
and can list the supported timezones and retrieve specific
timezone component data by using the CALDAV:calendar-query
REPORT defined in .
CalDAV defines the following new resource types for use in
WebDAV repositories holding calendar data.Calendar collections are manifested to clients as a WebDAV
resource collection, identified by a URL. A calendar collection
MUST have a non-empty DAV:displayname property (defined in
Section 13.2 of RFC2518), and
a DAV:resourcetype property (defined in Section 13.9 of
RFC2518). Additionally, 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:
]]>A calendar collection contains resources that represent
the iCalendar objects within a calendar. A calendar
collection may be created through provisioning (e.g.,
automatically created when a user's account is created), or
it may be created through MKCALENDAR. This 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 calendars are for, users must
rely on non-standard cues to find out what a calendar is
for, or use the CALDAV:calendar-description property defined
in to provide such a
cue. Calendar collections MUST NOT contain other calendar
collections. Multiple calendars MAY be children of the
same WebDAV collection. A calendar collection MAY contain additional collections and
non-collection resources of types not defined here. How
such items are used is not defined by this specification.
However, additional collections contained in a calendar
collection MUST NOT contain calendar collections. Each top-level iCalendar component within the VCALENDAR
component is represented as a separate WebDAV resource,
with the following exceptions
sets of recurring
items (i.e., components with the same UID iCalendar property
value, but differing RECURRENCE-ID values) are all stored
in the same resource. That is, each WebDAV resource MUST only
contain iCalendar components with the same iCalendar UID
property value, and all iCalendar components with the same
iCalendar UID property value MUST be stored in the same
WebDAV resource.any top-level component that
references a timezone via a "TZID" property MUST include
the VTIMEZONE component corresponding to that timezone id,
as required by iCalendar, unless the timezone is one
included in the server's timezone collection, as described in
.For example, given the following iCalendar object:
The VEVENT with UID value "1@example.com", would be stored
in its own unique WebDAV resource. The two VEVENTs with UID
value "2@example.com", which represent a set of recurring
events where one instance has been overridden, would be
stored in a single unique WebDAV resource.The creation of calendar collections and calendar 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 calendars or according to the
data model defined here.
A MKCALENDAR request creates a new calendar collection resource.
A server MAY restrict calendar collection creation to particular
collections, but a client can determine the location of these
collections from a CALDAV:calendar-collection-set OPTIONS request
(see ).
Support for MKCALENDAR on the server is OPTIONAL 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 calendars to better help
organize their data.
Clients SHOULD use the DAV:displayname property for a
human-readable name of the calendar. This requires the
clients to issue a PROPPATCH request to change the
DAV:displayname property to the appropriate value
immediately after issuing the MKCALENDAR request.
When displaying calendars 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.
]]>
If a response body for a successful request is included, it MUST
be a CALDAV:mkcalendar-response XML element.
]]>
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.
(CALDAV:calendar-collection-location-ok): The Request-URI MUST
identify a location where a calendar collection can be created.
(CALDAV:insufficient-privilege): The DAV:bind privilege MUST
be granted to the current authenticated user.
Postconditions:
(CALDAV:initialize-calendar-collection): A new calendar collection
exists at the Request-URI. The DAV:resourcetype of the calendar
collection MUST be DAV:collection. Additionally, a calendar
collection MUST report the CALDAV:calendar XML element in the
value of the DAV:resourcetype property.
201 (Created) - The calendar collection resource was created in
its entirety.
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.
405 (Method Not Allowed) - MKCALENDAR can only be executed on a
null resource.
409 (Conflict) - A collection cannot be made at the Request-URI until
one or more intermediate collections have been created.
415 (Unsupported Media Type)- The server does not support the request
type of the body.
507 (Insufficient Storage) - The resource does not have sufficient
space to record the state of the resource after the execution of this
method.
>> Request <<
MKCALENDAR /calendars/user/lisa/ HTTP/1.1
Host: cal.example.com
Content-Length: 0
>> Response <<
HTTP/1.1 201 Created
Date: Fri, 22 Oct 2004 12:17:08 GMT
Content-Length: 0
Cache-Control: no-cache
In this example, a new calendar collection is created at
http://cal.example.com/calendars/user/lisa/
If the server supports the calendar-access feature, 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, or methods. 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. >> Request << >> Response << In this example, the OPTIONS response indicates that the
server supports CalDAV in this namespace, therefore the
'/calendars/users/' collection may be used as a parent for
calendar collections as the MKCALENDAR method is available,
and as a possible target for REPORT requests for calendaring
reports.A CALDAV:calendar-collection-set element MAY be included in
the request body to identify collections that may contain
calendar collection resources.
Additional Marshalling:
If an XML request body is included, it MUST be a
DAV:options XML element.
ANY value: A sequence of elements with at most one
calendar-collection-set element.
]]>If an XML response body for a successful request
is included, it MUST be a DAV:options-response XML
element.
ANY value: A sequence of elements with at most one
calendar-collection-set element.
]]>If CALDAV:calendar-collection-set is included in the
request body, the response body for a successful request
MUST contain a CALDAV:calendar-collection-set element
identifying collections that may contain calendar collections.
An identified collection MAY be the root collection of a
tree of collections, all of which may contain calendar
collections. Since different servers can control different
parts of the URL namespace, different resources on the
same host MAY have different CALDAV:calendar-collection-set
values. The identified collections MAY be located on
different hosts from the resource.
A CALDAV:current-user-calendar-collection-set element MAY be
included in the request body to identify the calendar
collections owned by the current authenticated user.Additional Marshalling:
If an XML request body is included, it MUST be a
DAV:options XML element.
ANY value: A sequence of elements with at most one
current-user-calendar-collection-set element.
]]>If an XML response body for a successful request
is included, it MUST be a DAV:options-response XML
element.
ANY value: A sequence of elements with at most one
current-user-calendar-collection-set element.
]]>If CALDAV:current-user-calendar-collection-set is included in
the request body, the response body for a successful request
MUST contain a CALDAV:current-user-calendar-collection-set
element identifying calendar collections owned by the
current authenticated user.
We should probably put a note that one needs to be
authenticated before issuing this OPTIONS request.
Obviously.
A CALDAV:timezone-collection-set element MAY be included in
the request body to identify the calendar collections that
contains the set of calendar resources that defines the
timezone supported by the server.Additional Marshalling:
If an XML request body is included, it MUST be a
DAV:options XML element.
ANY value: A sequence of elements with at most one
timezone-collection-set element.
]]>If an XML response body for a successful request
is included, it MUST be a DAV:options-response XML
element.
ANY value: A sequence of elements with at most one
timezone-collection-set element.
]]>If CALDAV:timezone-collection-set is included in
the request body, the response body for a successful request
MUST contain a CALDAV:timezone-collection-set
element identifying calendar collections containing
the set of calendar resources that defines the
timezone supported by the server.
>> Request <<
]]>>> Response <<http://cal.example.com/calendars/user/http://cal.example.com/calendars/public/
]]>In this example, the server indicates that it provides Class 1 DAV
support and calendar-access support. In addition, the server
indicates the requested locations of the calendar collection
resources.Clients typically populate calendars with calendar resources.
The URL for each calendar resource is entirely arbitrary,
and does not need to bear a specific relationship (but
might) to the calendar resource's subject, scheduled time,
UID or other metadata. A new calendar resource must
have a new URL, otherwise the new component would instead
be an update to an existing calendar resource.When servers create new resources, it's not hard for the
server to choose a unique URL. 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 isn't created
with a name collision. However, there are tools 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 header "If-None-Match: *" on the PUT request. The
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' property. No matter how the name is chosen, the
"If-None-Match" header ensures that the client cannot
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. >> Request << >> Response << 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 mentionned in Section 3.10 of
RFC 2445, the URI of
calendar resources containing (an arbitrary set of)
calendaring and scheduling information may be
suffixed by ".ics", and the URI of calendar resources
containing free or busy time information may be
suffixed by ".ifb". A CalDAV server MAY return the Location header in a 201
(Created) response to a PUT request if the server created
the resource at a different URI than the Request-URI.
CalDAV clients MUST be able to handle the URI returned by
the server in the Location header, by adjusting their
original resource URI to the new one returned by the
server. This specification defines new properties for WebDAV resources.
Calendar access properties may be retrieved just like other WebDAV
properties, using the PROPFIND method.calendar-description
urn:ietf:params:xml:ns:caldavProvides a description for
the resource that is suitable for presentation
to a user.The CALDAV:calendar-description
property MAY be defined on all calendar collection
resources. If present, the property contains a
description of the resource that is suitable for
presentation layer.
]]>A CalDAV server MUST support WebDAV
ACL. WebDAV ACL provides a framework for an
extensible list of privileges on WebDAV collections and
ordinary resources. A CalDAV server MUST also support the
calendaring privilege defined in this section.Calendar users often wish to allow other users to see their
free-busy time intervals, without viewing the other details
of the calendar components (location, subject, attendees).
This allows a significant amount of privacy while still
allowing those other users to schedule meetings at times
when the calendar user is likely to be free. The CALDAV:view-free-busy privilege controls access
to view the start times and end times of free and busy
time intervals. This privilege may be granted on an entire
calendar collection. It may also make sense to grant this
privilege on individual calendar resources (in which case
the time allocated to those calendar resources would show
up as free in the free-busy rollup to an unauthorized viewer),
but a server MAY forbid the CALDAV:view-free-busy privilege
from being used on individual calendar resources. A CalDAV
server MUST support the CALDAV:view-free-busy privilege on
calendar collections.
]]> The CALDAV:view-free-busy privilege is aggregated in the
DAV:read privilege. Clients can discover support for
various privileges using the DAV:supported-privilege-set
property defined in RFC3744.
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 another, and 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 the total set of actions are allowed), it is aggregated
under the DAV:read privilege. Although the list of supported
privileges MAY vary somewhat from server to server (the
WebDAV ACL specification leaves room for a fair amount of
diversity in server implementations), some relationships
MUST hold for a CalDAV server: The server MUST support the CALDAV:view-free-busy privilege.
The CALDAV:view-free-busy privilege MUST be non-abstract, and MUST
be aggregated under the DAV:read privilege.This is a partial example of how the
DAV:supported-privilege-set property could look on a
server supporting CalDAV. Note that aggregation is
shown in the structure of the DAV:supported-privilege
elements containing each other.Any operation
Read any object
Read ACL
Read current user privilege
setView free-busy rollup
Write any object
...
]]>This section defines a new property for WebDAV principal
resources as defined in RFC3744.
calendar-URL
urn:ietf:params:xml:ns:caldav
Identify the URL of any calendar collections owned
by the associated principal resource.
]]>Support for this property is RECOMMENDED.This section defines the reports which a CalDAV server MUST
support on calendar collections and calendar resources.CalDAV servers MUST advertise support for those reports
with the DAV:supported-report-set property defined in
DeltaV.Some of these reports allow calendar data (from possibly
multiple resources) to be returned. Clients SHOULD request the
DAV:getetag property whenever executing reports that return
calendar data, to ensure that any local cache used for
synchronization is kept up to date with the latest changes
on the serverThe REPORT method (defined in Section 3.6 of
RFC3253) provides an
extensible mechanism for obtaining information about a resource.
Unlike the PROPFIND method, which returns the value of one or more
named properties, the REPORT method can involve more complex
processing. REPORT is valuable in cases where the server has access
to all of the information needed to perform the complex request (such
as a query), 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 MUST support the
DAV:expand-property report (defined in Section 3.8 of
RFC3253).A WebDAV collection which contains one or more calendar
collections is not a new type of resource, but it may
support these new REPORT. If so, then the REPORT is
expected to have the semantics of including information
from all the calendar data contained in the collection,
and its children, recursively. These collections may
contain more than only calendar related resources. It's
up to the server, if it supports this REPORT on a normal WebDAV
collection, to find calendar resources and decide
what to do with non-calendar resources and whether those
may also appear in the collection or its children. If these reports are supported on ordinary collections the
server advertises the capability with the
DAV:supported-report-set property as already described.The CALDAV:calendar-query REPORT performs a search for all
calendar resources (e.g., iCalendar objects) that match a
specified search filter. The response of this report will
contain all the WebDAV properties and calendar 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 resource data
that matches the search 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 calendar-query REPORT is REQUIRED. Marshalling: The request body MUST be a
CALDAV:calendar-query XML element as defined in . 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 multistatus XML element is
empty. The response body for a successful
calendar-query REPORT request MUST contain a DAV:response
element for each iCalendar object that matched the search
filter. The declaration of the DAV:response element from
Section 12.9.1 of RFC2518 has
been modified as follow to allow the CALDAV:calendar-data
element within the DAV:response element, see
We need to define the role of the Depth request header
when applied to a collection resource.
We need to specify preconditions and postconditions.
(e.g., DAV:number-of-matches-within-limits).
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 2nd, 2004 at
11:59:59 pm UTC. In addition the DAV:getetag
property is also requested and returned as part of the
response. >> Request <<
]]>>> Response <<http://cal.example.com/bernard/calendar/ev102.ics"23ba4d-ff11fb"HTTP/1.1 200 OKBEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
DTSTART:20040902T100000Z
DTEND:20040902T120000Z
SUMMARY:Design meeting
UID:34222-232@example.com
X-ABC-GUID:E1CX4zp-0005Ld-21@example.com
END:VEVENT
END:VCALENDAR
http://cal.example.com/bernard/calendar/mtg103.ics"ff11fb-23ba4d"HTTP/1.1 200 OKBEGIN: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
]]> In this example, the client requests the server to
return the VTODO components that have an alarm trigger
scheduled in the specified time range. >> Request <<
]]> In this example, the client requests the server to
return the VEVENT component that has the UID property
set to "20041121-FEEBDAED@foo.org". >> Request <<20041121-FEEBDAED@foo.org
]]> In this example, the client requests the server to
return the VEVENT components that have the ATTENDEE
property with the value "mailto:jsmith@example.org" and
for which the PARTSTAT parameter is set to
"NEEDS-ACTION". >> Request <<mailto:jsmith@foo.orgNEEDS-ACTION
]]> In this example, the client requests the server to
return all VEVENT components. >> Request <<
]]>The following examples illustrate two common operations
a client may want to perform on the CalDAV server's
timezone collection. These examples assume that the
client has already got the URI for the server's
timezone calendar collection. In this example, the client requests the server to
return all VTIMEZONE components, with just their
TZID property, and without the embedded DAYLIGHT
and STANDARD components.
A client might also want to get a human-readable
display name for the VTIMEZONE components.
Unfortunately, there is no such property defined
in iCalendar. The TZNAME property is defined in
the DAYLIGHT and STANDARD components and would
have a value such as "US Eastern Standard Time"
or "US Eastern Daylight Time". What a client
would need here, is a time zone name irrespective
of the "Standard" or "Daylight" observance, e.g.,
"US Eastern Time". Perhaps we should recommend
the use of the DAV:displayname property on
timezone resources.
>> Request <<
]]>>> Response <<http://cal.example.com/calendar/timezones/tz1.ics"tz1-20050125"HTTP/1.1 200 OKBEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VTIMEZONE
TZID:America/New_York
END:VTIMEZONE
END:VCALENDAR
http://cal.example.com/calendar/timezones/tz2.ics"tz2-20050125"HTTP/1.1 200 OKBEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VTIMEZONE
TZID:America/Los_Angeles
END:VTIMEZONE
END:VCALENDAR
]]>The CALDAV:calendar-multiget REPORT is used to retrieve specific
calendar resources from within a collection, if the
Request-URI is a collection, or to retrieve a specific
calendar resource, if the Request-URI is a calendar
resource. This report is similar to the
CALDAV:calendar-query REPORT (see ), except that it takes a list of
DAV:href elements instead of a CALDAV:filter element to determine
which calendar resources to return.Support for the calendar-multiget REPORT is REQUIRED.Marshalling: The request body MUST be a
CALDAV:calendar-multiget XML element (see , which MUST contain at
least one DAV:href XML element, and one optional
CALDAV:calendar-data element as defined in . 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 to the Request-URI.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 multistatus XML element is
empty.The response body for a successful
CALDAV:calendar-multiget REPORT request MUST contain a
DAV:response element for each calendar resource referenced by
the provided set of DAV:href elements. The DAV:response element
is as defined in .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. In this example, the client requests the server to
return specific properties of the VEVENT components
references 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/bernard/calendar/mtg1.ics does
not exist, resulting in an error status response. >> Request <<http://cal.example.com/bernard/calendar/ev102.icshttp://cal.example.com/bernard/calendar/mtg1.ics
]]>>> Response <<http://cal.example.com/bernard/calendar/ev102.ics"23ba4d-ff11fb"HTTP/1.1 200 OKBEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VEVENT
DTSTART:20040902T100000Z
DTEND:20040902T120000Z
SUMMARY:Design meeting
UID:34222-232@example.com
END:VEVENT
END:VCALENDAR
http://cal.example.com/bernard/calendar/mtg1.icsHTTP/1.1 404 Resource not found
]]>The CALDAV:free-busy-query REPORT generates an iCalendar
VFREEBUSY component containing free busy information for all
relevant components within calendar collections which have the
CALDAV:view-free-busy or DAV:read privilege granted for the
current authenticated user.Only the VEVENT components, with the TRANSP property set
to a value different from "TRANSPARENT", and the VFREEBUSY
components will be considered to generate the free busy time
information.Support for the CALDAV:free-busy-query REPORT is REQUIRED.Marshalling:
The request body MUST be a CALDAV:free-busy-query XML
element (see , which
MUST contain at least one CALDAV:time-range XML element,
as defined in .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 multistatus XML element
is empty.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
. The
CALDAV:calendar-data XML element MUST contain an
iCalendar object with a single VFREEBUSY component,
with zero or more FREEBUSY property values that describe
the busy time intervals for the calendar 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 "text/calendar" VEVENT resources within
the calendar collection, irrespective of the value of any
Depth header included in the REPORT request. Only calendar
resources containing VEVENT or VFREEBUSY components that
have the CALDAV:view-free-busy privilege granted to the
current authenticated 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 the request as
follows: 'Depth: 0' - an empty VFREEBUSY
component will be returned as there is no valid calendar
data to be scanned on the collection.'Depth:
1' - free-busy data for any calendar collections
immediately within the target collection is returned.'Depth: infinity' - free-busy data for all calendar
collections within any sub-collections of the target
collection is returned.In this example, the client requests the server to
return free-busy information on the calendar collection
/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 <<
]]>>> Response <<http://cal.example.com/bernard/calendar/HTTP/1.1 200 OKBEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VFREEBUSY
DTSTAMP:20050125T090000Z
DTSTART:20040902T090000Z
DTEND:20040902T170000Z
FREEBUSY:20040902T090000Z/PT1H,
20040902T120000Z/PT2H,
20040902T160000Z/PT30M
END:VFREEBUSY
END:VCALENDAR
]]>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 applications than to other WebDAV
applications, CalDAV servers MUST support strong ETags. The 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
calendars 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
from the server using CALDAV:calendar-query report combined
with a time-range element to limit the scope of
returned items to just those needed to populate the
current view.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 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.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 URI and ETag along with the
actual calendar data. Whilst the URI remains static for
the lifetime of the component, the ETag will change
with each successive change to the component data. 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.In order to properly detect the changes between the
server and client data, the client will need to keep a
record of which items have been created, changed or
deleted since the last synchronization operation so
that it can reconcile those changes with the data on
the server.An example of how to do that would be the following:
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:
]]>The client then uses the results to
determine which components have changed, been created
or deleted on the server and how those relate to
locally cached components that may have changed, been
created or deleted. If the client determines that there
are items on the server that need to be fetched, the
client issues a CALDAV:calendar-multiget report to fetch the
actual data: http://cal.example.com/bernard/calendar/evt1.icshttp://cal.example.com/bernard/calendar/mtg1.ics
]]>Clients may not need all the properties in a calendar
component when presenting information to the user. Since
some property data can be large (e.g., 'ATTACH' or
'ATTENDEE' lists) 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.However, if a client needs to make a change to a component,
it can only change the entire component data via a PUT
request. There is no way to incrementally make a change to
a set of properties within a calendar component resource.
As a result the client will have to cache the entire set of
properties on a resource that is being changed. Clients should use the set of timezone components in
the server's timezone collection advertises in
the namespace report, for any timezones for calendar
components that it creates. This avoids the need for the
client or server to send the timezone data along with the
component data and thus reduces network bandwidth usage.calendar-query
urn:ietf:params:xml:ns:caldavDefines a report for querying
calendar dataSee .
]]>calendar-data
urn:ietf:params:xml:ns:caldavUsed to define which parts
of a calendar component object should be
returned by the report that uses this
element.When used in a request,
the CALDAV:calendar-data element specifies the
iCalendar components and properties to be
returned in the iCalendar objects part of the
response. If this element doesn't contain any
CALDAV:comp element, iCalendar objects will be
returned with all their components and
properties.When used inside a
response, the CALDAV:calendar-data element contains
an iCalendar object that matched the search
filter specified in the request.
]]>comp
urn:ietf:params:xml:ns:caldavDefines which component
types to returnThe name value is an
iCalendar component name (e.g.,
"VEVENT")NOTE: The CALDAV:prop and CALDAV:allprop elements used
here have the same name as elements defined in WebDAV.
However, the elements used here have the
"urn:ietf:params:xml:ns:caldav" namespace, as
opposed to the "DAV:" namespace used for elements
defined in WebDAV.
]]>allcomp
urn:ietf:params:xml:ns:caldavSpecifies that all
components shall be returnedThis element can
be used when the client wants all types
of components returned by a report.
]]>allprop
urn:ietf:params:xml:ns:caldavSpecifies that all
properties shall be returned.This element can
be used when the client wants all
properties of components returned by a
report.NOTE: The 'allprop' element defined here has the
same name as the 'allprop' element defined in
WebDAV. However, the 'allprop' element defined
here uses the "urn:ietf:params:xml:ns:caldav"
namespace, as opposed to the "DAV:" namespace
used for the 'allprop' element defined in
WebDAV.
]]>prop
urn:ietf:params:xml:ns:caldavDefines which
properties to return in the
response.The "name"
attribute specifies the name of the
iCalendar 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: The 'prop' element defined here has the
same name as the 'prop' element defined in
WebDAV. However, the 'prop' element defined
here uses the "urn:ietf:params:xml:ns:caldav"
namespace, as opposed to the "DAV:" namespace
used for the 'prop' element defined in
WebDAV.
]]> expand-recurrence-set
urn:ietf:params:xml:ns:caldavForces the server to
expand recurring components into separate
instances.The
expand-recurrence-set element specifies
that recurring components shall be returned
as multiple components with no recurrence
properties (i.e., EXDATE, EXRULE, RDATE and
RRULE). The required "start" and "end"
attributes contain iCalendar format
DATE-TIME (always specified in UTC) or DATE
values that define the time interval over
which the recurrence expansion should take
place. The start value is inclusive and the
end value is exclusive of the interval as per
iCalendar DTSTART and DTEND properties. The
server MUST return only those expanded
components whose time interval intersects
the interval specified by the start and end
attributes.
]]>filter
urn:ietf:params:xml:ns:caldavDetermines which matching
components are returned.The "filter" element
specifies the search filter used to match
components that should be returned by a
report.
]]>comp-filter
urn:ietf:params:xml:ns:caldavLimits the search to
only the chosen component types.The "name" attribute
is an iCalendar component type (e.g.,
"VEVENT"). When this element is present,
the server should only return a component
if it matches the filter, which is to say:
]]>prop-filter
urn:ietf:params:xml:ns:caldavLimits the search to
specific properties.The "name" attribute
MUST contain an iCalendar property name
(e.g., "ATTENDEE"). When the 'prop-filter'
executes, a property matches if:
]]>param-filter
urn:ietf:params:xml:ns:caldavLimits the search to
specific parameters.The "param-filter"
element limits the search result to the set
of resources containing properties with
parameters that meet the parameter filter
rules. When this filter executes, a
parameter matches if:
]]>is-defined
urn:ietf:params:xml:ns:caldavCauses a search to match
a resource if a component type, property or
parameter name exists.The CALDAV:is-defined
XML element limits the filter to resources
where the named component, property or
parameter is defined.
]]>text-match
urn:ietf:params:xml:ns:caldavSpecifies a substring
match on a property or parameter value.The specified text
is used for a substring match against the
property or parameter value specified in a
report. 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 ().
Support for the "caseless" attribute is
optional. A server should respond with a
status of 422 if it is used but cannot be
supported.
]]>time-range
urn:ietf:params:xml:ns:caldavSpecifies a time interval
for testing components against.The CALDAV:time-range
element allows for a single time range to
be defined, in order to limit all the
results of the search to the set of
resources that contain a component which
falls into that time range. The value of
the "start" and "end" attributes MUST
follow the syntax of the DATE or DATE-TIME
iCalendar value type, with any time
specified in UTC. A VEVENT component falls in a given
time-range if: start) OR
(DTSTART <= start AND DTSTART+DURATION > start) OR
(DTSTART >= start AND DTSTART < end) OR
(DTEND > start AND DTEND <= end)
]]> A VTODO component falls in a given
time-range if: = start) OR
(DTSTART <= start AND DTSTART+DURATION > start) OR
(DTSTART >= start AND DTSTART < end) OR
(DUE >= start AND DUE < end)
]]> A VJOURNAL component falls in a given
time-range if: = start AND DTSTART < end
]]> A VALARM component falls in a given
time-range if: = start AND trigger-time < end
]]> Any property of value type DATE-TIME or
DATE (e.g., DTSTAMP) will match a given
time-range if: = start AND value < end
]]>
]]>response DAV:Response that includes calendar
data.Modifies the standard WebDAV
response element to include calendar data in the
response if required by the report type.
]]>calendar-multiget
urn:ietf:params:xml:ns:caldavCalDAV report used to retrieve
specific calendar component items via their
URIs.See .
]]>free-busy-query
urn:ietf:params:xml:ns:caldavCalDAV report used to generate a
VFREEBUSY to determine busy time over a specific
set of time ranges.See .
]]>CalDAV relies on HTTP authentication to authenticate users to
the server. As a result the security considerations for use of
HTTP authentication also apply to CalDAV. In particular, the
HTTP Basic authentication method MUST NOT be used without
adequate transport layer security.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 event occurring every second for the next
100 years which would result in approximately 3 x 10^9
instances! A report that asks for recurrences to be expanded
over that range would likely constitute a denial-of-service
attack on the server.
We should make an explicit reference to the security
considerations mentionned in iCalendar, iTIP and iMIP.
We should also specify if there is any semantic defined
in CalDAV for the iCalendar property CLASS (access
classification).
In addition to the namespaces defined by RFC2518 for XML elements, this document
uses a URN to describe a new XML namespace conforming to a
registry mechanism described in RFC3688. All other IANA considerations
mentioned in RFC2518 also apply
to this document.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. The authors would like to thank the following individuals
for contributing their ideas and support for writing this
specification: Michael Arick, Mario Bonin, Scott Carr,
Helge Hess, Dan Mosedale, Julian F. Reschke, Mike Shaver,
Simon Vaillancourt, and Jim Whitehead.
The authors would also like to thank the Calendaring and
Scheduling Consortium for advice with this specification,
and for organizing interoperability testing events to help
refine it.
Key words for use in RFCs to Indicate Requirement LevelsHarvard University1350 Mass. Ave.CambridgeMA 02138- +1 617 495 3864sob@harvard.edu
General
keyword
In many standards track documents several words are used to signify
the requirements in the specification. These words are often
capitalized. This document defines these words as they should be
interpreted in IETF documents. Authors who follow these guidelines
should incorporate this phrase near the beginning of their document:
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
RFC 2119.
Note that the force of these words is modified by the requirement
level of the document in which they are used.
Internet Calendaring and Scheduling Core Object Specification (iCalendar)Lotus Development Corporation6544 Battleford DriveRaleighNC27613-3502USA+1-919-676-9515+1-919-676-9564Frank_Dawson@Lotus.comhttp://home.earthlink.net/~fdawsonMicrosoft CorporationOne Microsoft WayRedmondWA98052-6399USA+1-425-936-5522+1-425-936-7329deriks@Microsoft.com
Applications
calendaringschedulingPIM
There is a clear need to provide and deploy interoperable calendaring
and scheduling services for the Internet. Current group scheduling
and Personal Information Management (PIM) products are being extended
for use across the Internet, today, in proprietary ways. This memo
has been defined to provide the definition of a common format for
openly exchanging calendaring and scheduling information across the
Internet.
This memo is formatted as a registration for a MIME media type per
. However, the format in this memo is equally applicable
for use outside of a MIME message content type.
The proposed media type value is 'text/calendar'. This string would
label a media type containing calendaring and scheduling information
encoded as text characters formatted in a manner outlined below.
This MIME media type provides a standard content type for capturing
calendar event, to-do and journal entry information. It also can be
used to convey free/busy time information. The content type is
suitable as a MIME message entity that can be transferred over MIME
based email systems, using HTTP or some other Internet transport. In
addition, the content type is useful as an object for interactions
between desktop applications using the operating system clipboard,
drag/drop or file systems capabilities.
This memo is based on the earlier work of the vCalendar specification
for the exchange of personal calendaring and scheduling information.
In order to avoid confusion with this referenced work, this memo is
to be known as the iCalendar specification.
This memo defines the format for specifying iCalendar object methods.
An iCalendar object method is a set of usage constraints for the
iCalendar object. For example, these methods might define scheduling
messages that request an event be scheduled, reply to an event
request, send a cancellation notice for an event, modify or replace
the definition of an event, provide a counter proposal for an
original event request, delegate an event request to another
individual, request free or busy time, reply to a free or busy time
request, or provide similar scheduling messages for a to-do or
journal entry calendar component. The iCalendar Transport-indendent
Interoperability Protocol (iTIP) defined in is one such
scheduling protocol.
HTTP Extensions for Distributed Authoring -- WEBDAVMicrosoft CorporationOne Microsoft WayRedmondWA98052-6399yarong@microsoft.comDept. Of Information and Computer Science,
University of California, IrvineIrvineCA92697-3425ejw@ics.uci.eduNetscape685 East Middlefield RoadMountain ViewCA94043asad@netscape.comNovell1555 N. Technology WayM/S ORM F111OremUT84097-2399srcarter@novell.comNovell1555 N. Technology WayM/S ORM F111OremUT84097-2399dcjensen@novell.com
This document specifies a set of methods, headers, and content-types
ancillary to HTTP/1.1 for the management of resource properties,
creation and management of resource collections, namespace
manipulation, and resource locking (collision avoidance).
Hypertext Transfer Protocol -- HTTP/1.1Department of Information and Computer ScienceUniversity of California, IrvineIrvineCA92697-3425+1(949)824-1715fielding@ics.uci.eduWorld Wide Web ConsortiumMIT Laboratory for Computer Science, NE43-356545 Technology SquareCambridgeMA02139+1(617)258-8682jg@w3.orgCompaq Computer CorporationWestern Research Laboratory250 University AvenuePalo AltoCA94305mogul@wrl.dec.comWorld Wide Web ConsortiumMIT Laboratory for Computer Science, NE43-356545 Technology SquareCambridgeMA02139+1(617)258-8682frystyk@w3.orgXerox CorporationMIT Laboratory for Computer Science, NE43-3563333 Coyote Hill RoadPalo AltoCA94034masinter@parc.xerox.comMicrosoft Corporation1 Microsoft WayRedmondWA98052paulle@microsoft.comWorld Wide Web ConsortiumMIT Laboratory for Computer Science, NE43-356545 Technology SquareCambridgeMA02139+1(617)258-8682timbl@w3.org
The Hypertext Transfer Protocol (HTTP) is an application-level
protocol for distributed, collaborative, hypermedia information
systems. It is a generic, stateless, protocol which can be used for
many tasks beyond its use for hypertext, such as name servers and
distributed object management systems, through extension of its
request methods, error codes and headers . A feature of HTTP is
the typing and negotiation of data representation, allowing systems
to be built independently of the data being transferred.
HTTP has been in use by the World-Wide Web global information
initiative since 1990. This specification defines the protocol
referred to as "HTTP/1.1", and is an update to RFC 2068 .
Versioning Extensions to WebDAV (Web Distributed Authoring and Versioning)Rational Software20 Maguire RoadLexingtonMA02421USgeoffrey.clemm@rational.comIBM3039 CornwallisResearch Triangle ParkNC27709USjamsden@us.ibm.comIBMHursley ParkWinchesterS021 2JNUKtim_ellison@uk.ibm.comMicrosoftOne Microsoft WayRedmondWA90852USckaler@microsoft.comUC Santa Cruz, Dept. of Computer Science1156 High StreetSanta CruzCA95064USejw@cse.ucsc.edu
This document specifies a set of methods, headers, and resource types
that define the WebDAV (Web Distributed Authoring and Versioning)
versioning extensions to the HTTP/1.1 protocol. WebDAV versioning
will minimize the complexity of clients that are capable of
interoperating with a variety of versioning repository managers, to
facilitate widespread deployment of applications capable of utilizing
the WebDAV Versioning services. WebDAV versioning includes automatic
versioning for versioning-unaware clients, version history
management, workspace management, baseline management, activity
management, and URL namespace versioning.
The IETF XML RegistryThis document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. Web Distributed Authoring and Versioning (WebDAV) Access Control ProtocolIBM20 Maguire RoadLexingtonMA02421geoffrey.clemm@us.ibm.comgreenbytes GmbHSalzmannstrasse 152MuensterNW48159Germanyjulian.reschke@greenbytes.deOracle Corporation500 Oracle ParkwayRedwood ShoresCA94065eric.sedlar@oracle.comU.C. Santa Cruz, Dept. of Computer Science1156 High StreetSanta CruzCA95064ejw@cse.ucsc.edu
This document specifies a set of methods, headers, message bodies,
properties, and reports that define Access Control extensions to the
WebDAV Distributed Authoring Protocol. This protocol permits a client to
read and modify access control lists that instruct a server whether to
allow or deny operations upon a resource (such as HyperText Transfer
Protocol (HTTP) method invocations) by a given principal. A lightweight
representation of principals as Web resources supports integration of a
wide range of user management repositories. Search operations allow
discovery and manipulation of principals using human names.
Extensible Markup Language (XML) 1.0 (Third Edition)Textuality and Netscapetbray@textuality.comMicrosoftjeanpa@microsoft.comUniversity of Illinois at Chicago and Text Encoding Initiativecmsmcq@uic.eduSun Microsystemseve.maler@east.sun.comfrancois@yergeau.comThe Unicode Standard - Version 4.0The Unicode ConsortiumISBN 0321185781The following table extend the WebDAV Method Privilege Table
specified in Appendix B of WebDAV ACL.
METHODPRIVILEGESMKCALENDARDAV:bindREPORTDAV:read or CALDAV:view-free-busy
(on all referenced resources)Removed a lot of non-normative text.Removed property promotion/demotion requirements.Removed calendar-owner and cal-scale properties.Removed 'ical' prefix/text from element names.Relaxed WebDAV Class 2 (locking) requirement to a MAY.Relaxed MKCALENDAR requirement to a SHOULD.Moved the XML Namespace section in the Introduction.Added CALDAV: prefix to CalDAV XML elements in the text.Added CALDAV:calendar-multiget report.Added CALDAV:free-busy-query report.Added CALDAV:calendar-description property.Changed CALDAV:calendar-query-result element name to
CALDAV:calendar-dataAdded description and examples of handling timezones.Added mandatory "start" and "end" attributes to the
CALDAV:expand-recurrence-set element.Added three CalDAV OPTIONS requests.Grouped XML Element declarations in a separate section.Added a note about the HTTP Location response
header.Added report calendar-query.Removed reports calendar-property-search and
calendar-time-range.Removed section on CalDAV and timezones.Added requirement to return ETag on creation.Revised data model to remove sub-collections from
calendar collection.Added informative references section.Removed dependencies on DASL.Removed Calendar Containers (simplification that
doesn't seem to remove much functionality)Added MKCALENDAR to create calendars and all
sub-collectionsAdded cal-scale property to calendarsBasically still adding major sections of content: Defined new field values to the OPTIONS
"DAV:" response headerAdded new resource
propertiesAdded new principal propertiesAdded new SCHEDULE method and related headersAdded new privileges for schedulingAdded section on privileges for calendaring,
extending WebDAV ACL privilege setDefined what to do with unrecognized properties in
the bodies of iCalendar events, with respect to
property promotion/demotion