Calendaring Extensions to WebDAV (CalDAV)

The concept of using HTTP and WebDAV as a basis for a 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 calendar access protocols using HTTP to upload and download iCalendar objects, and using WebDAV 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 way to model calendar data in WebDAV, with additional features to make an interoperable calendar access protocol.

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 . The term "protected" is used in the Conformance field of property definitions as defined 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 type names, respectively.

Definitions of XML elements in this document use XML element type declarations (as found in XML Document Type Declarations), described in . The namespace "urn:ietf:params:xml:ns:caldav" is reserved for the XML elements defined in this specification, its revisions, and related CalDAV specifications. XML elements defined by individual implementations &MUST-NOT; 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 do not include namespace information. Thus, implementers must not use these declarations as the only way to create valid CalDAV properties or to validate CalDAV XML element types. Some of the declarations refer to XML elements defined by WebDAV, which use the "DAV:" namespace. Wherever such XML elements appear, they are explicitly prefixed with "DAV:" to 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. Processing of XML by CalDAV clients and servers &MUST; follow the rules described in ; in particular, , and Appendix 3 of that specification.

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; either be 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.

This section lists what functionality is required of a CalDAV server. To advertise support for CalDAV, a server: &MUST; support iCalendar as a media type for the calendar object resource format; &MUST; support WebDAV Class 1 (note that describes clarifications to that aid interoperability); &MUST; support WebDAV ACL with the additional privilege defined in of this document; &MUST; support transport over TLS as defined in (note that has been obsoleted by ); &MUST; support ETags with additional requirements specified in of this document; &MUST; support all calendaring reports defined in of this document; and &MUST; advertise support on all calendar collections and calendar object resources for the calendaring reports in the DAV:supported-report-set property, as defined in Versioning Extensions to WebDAV. In addition, a server: &SHOULD; support the MKCALENDAR method defined in of this document.

One of the features that 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. As a brief overview, a CalDAV calendar is modeled as a WebDAV collection with a defined structure; each calendar collection contains a number of resources representing calendar objects as its direct child resource. Each resource representing a calendar object (event, to-do, 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. Requirements derived from this model are provided in and .

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 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. Therefore, 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. 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. Entity tags and other features make this possible.

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 rules, recurrence dates, exception rules, and exception 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 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 rule. It makes it easier to create a recurring calendar component and 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.

Calendar object resources contained in calendar collections &MUST-NOT; contain more than one type of calendar component (e.g., VEVENT, VTODO, VJOURNAL, VFREEBUSY, 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 one VEVENT component and one VTIMEZONE component, but it cannot contain one VEVENT component and one VTODO component. Instead, the VEVENT and VTODO components would have to be stored in separate calendar object resources in the same collection. Calendar object resources contained in calendar collections &MUST-NOT; specify the iCalendar METHOD property. The UID property value of the calendar components contained in a calendar object resource &MUST; be unique in the scope of the calendar collection in which they are stored. Calendar components in a calendar collection that have different UID property values &MUST; be stored in separate calendar object resources. Calendar components with the same UID property value, in a given calendar collection, &MUST; be contained in the same calendar object resource. This ensures that all components in a recurrence "set" are contained in the same calendar object resource. It is possible for a calendar object resource to just contain components that represent "overridden" instances (ones that modify the behavior of a regular instance, and thus include a RECURRENCE-ID property) without also including the "master" recurring component (the one that defines the recurrence "set" and does not contain any RECURRENCE-ID property). For example, given the following iCalendar object:

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.

A calendar collection contains calendar object resources 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:

]]> A calendar collection can be created through provisioning (i.e., automatically created when a user's account is provisioned), or it can be created with the MKCALENDAR method (see ). This method can be useful for a user to create additional calendars (e.g., soccer schedule) or for users to share a calendar (e.g., team events or conference rooms). However, note that this document doesn't define the purpose of extra calendar collections. 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 to provide such a cue. The following restrictions are applied to the resources within a calendar collection: Calendar collections &MUST; only contain calendar object resources and collections that are not calendar collections, i.e., the only "top-level" non-collection resources allowed in a calendar collection are calendar object resources. This ensures that calendar clients do not have to deal with non-calendar data in a calendar collection, though they do have to distinguish between calendar object resources and collections when using standard WebDAV techniques to examine the contents of a collection. Collections contained in calendar collections &MUST-NOT; contain calendar collections at any depth, i.e., "nesting" of calendar collections within other calendar collections at any depth is not allowed. This specification does not define how collections contained in a calendar collection are used or how they relate to any calendar object resources contained in the calendar collection. Multiple calendar collections &MAY; be children of the same collection.

A server supporting the features described in this document &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, 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.

>> Request <<

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

This section defines properties for calendar collections.

calendar-description urn:ietf:params:xml:ns:caldav Provides a human-readable description of the calendar collection. This property &MAY; be defined on any calendar collection. If defined, it &MAY; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). 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. If present, the property contains a description of the calendar collection that is suitable for presentation to a user. If not present, the client should assume no description for the calendar collection.

PCDATA value: string]]>

Calendrier de Mathilde Desruisseaux]]>

calendar-timezone urn:ietf:params:xml:ns:caldav Specifies a time zone on a calendar collection. This property &SHOULD; be defined on all calendar collections. If defined, it &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:calendar-timezone property is used 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. In the absence of this property, the server &MAY; rely on the time zone of their choice. The iCalendar data embedded within the CALDAV:calendar-timezone XML element &MUST; follow the standard XML character data encoding rules, including use of <, >, & etc. entity encoding or the use of a <![CDATA[ ... ]]> construct. In the later case, the iCalendar data cannot contain the character sequence "]]>", which is the end delimiter for the CDATA section.

PCDATA value: an iCalendar object with exactly one VTIMEZONE component.]]>

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 ]]>

supported-calendar-component-set urn:ietf:params:xml:ns:caldav Specifies the calendar component types (e.g., VEVENT, VTODO, etc.) that calendar object resources can contain in the calendar collection. This property &MAY; be defined on any calendar collection. If defined, it &MUST; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:supported-calendar-component-set property is used to specify restrictions on the calendar component types that calendar object resources may contain in a calendar collection. Any attempt by the client to store calendar object resources with component types not listed in this property, if it exists, &MUST; result in an error, with the CALDAV:supported-calendar-component precondition () being violated. 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 empty-element tag <C:comp name="VTIMEZONE"/> &MUST; only be specified if support for calendar object resources that only contain VTIMEZONE components is provided or desired. Support for VTIMEZONE components in calendar object resources that contain VEVENT or VTODO components is always assumed. In the absence of this property, the server &MUST; accept all component types, and the client can assume that all component types are accepted.

]]>

supported-calendar-data urn:ietf:params:xml:ns:caldav Specifies what media types are allowed for calendar object resources in a calendar collection. This property &MAY; be defined on any calendar collection. If defined, it &MUST; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:supported-calendar-data property is used to specify the media type supported for the calendar object resources contained in a given calendar collection (e.g., iCalendar version 2.0). Any attempt by the client to store calendar object resources with a media type not listed in this property &MUST; result in an error, with the CALDAV:supported-calendar-data precondition () being violated. In the absence of this property, the server &MUST; only accept data with the media type "text/calendar" and iCalendar version 2.0, and clients can assume that the server will only accept this data.

]]>

max-resource-size urn:ietf:params:xml:ns:caldav Provides a numeric value indicating the maximum size of a resource in octets that the server is willing to accept when a calendar object resource is stored in a calendar collection. This property &MAY; be defined on any calendar collection. If defined, it &MUST; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:max-resource-size is used to specify a numeric value that represents the maximum size in octets that the server is willing to accept when a calendar object resource is stored in a calendar collection. Any attempt to store a calendar object resource exceeding this size &MUST; result in an error, with the CALDAV:max-resource-size precondition () being violated. In the absence of this property, the client can assume that the server will allow storing a resource of any reasonable size.

PCDATA value: a numeric value (positive integer)]]>

102400]]>

min-date-time urn:ietf:params:xml:ns:caldav Provides a DATE-TIME value indicating the earliest date and time (in UTC) that the server is willing to accept for any DATE or DATE-TIME value in a calendar object resource stored in a calendar collection. This property &MAY; be defined on any calendar collection. If defined, it &MUST; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:min-date-time is used to specify an iCalendar DATE-TIME value in UTC that indicates the earliest inclusive date that the server is willing to accept for any explicit DATE or DATE-TIME value in a calendar object resource stored in a calendar collection. Any attempt to store a calendar object resource using a DATE or DATE-TIME value earlier than this value &MUST; result in an error, with the CALDAV:min-date-time precondition () being violated. Note that servers &MUST; accept recurring components that specify instances beyond this limit, provided none of those instances have been overridden. In that case, the server &MAY; simply ignore those instances outside of the acceptable range when processing reports on the calendar object resource. In the absence of this property, the client can assume any valid iCalendar date may be used at least up to the CALDAV:max-date-time value, if that is defined.

PCDATA value: an iCalendar format DATE-TIME value in UTC]]>

19000101T000000Z]]>

max-date-time urn:ietf:params:xml:ns:caldav Provides a DATE-TIME value indicating the latest date and time (in UTC) that the server is willing to accept for any DATE or DATE-TIME value in a calendar object resource stored in a calendar collection. This property &MAY; be defined on any calendar collection. If defined, it &MUST; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:max-date-time is used to specify an iCalendar DATE-TIME value in UTC that indicates the inclusive latest date that the server is willing to accept for any date or time value in a calendar object resource stored in a calendar collection. Any attempt to store a calendar object resource using a DATE or DATE-TIME value later than this value &MUST; result in an error, with the CALDAV:max-date-time precondition () being violated. Note that servers &MUST; accept recurring components that specify instances beyond this limit, provided none of those instances have been overridden. In that case, the server &MAY; simply ignore those instances outside of the acceptable range when processing reports on the calendar object resource. In the absence of this property, the client can assume any valid iCalendar date may be used at least down to the CALDAV:min-date-time value, if that is defined.

PCDATA value: an iCalendar format DATE-TIME value in UTC]]>

20491231T235959Z]]>

max-instances urn:ietf:params:xml:ns:caldav Provides a numeric value indicating the maximum number of recurrence instances that a calendar object resource stored in a calendar collection can generate. This property &MAY; be defined on any calendar collection. If defined, it &MUST; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:max-instances is used to specify a numeric value that indicates the maximum number of recurrence instances that a calendar object resource stored in a calendar collection can generate. Any attempt to store a calendar object resource with a recurrence pattern that generates more instances than this value &MUST; result in an error, with the CALDAV:max-instances precondition () being violated. In the absence of this property, the client can assume that the server has no limits on the number of recurrence instances it can handle or expand.

PCDATA value: a numeric value (integer greater than zero)]]>

100]]>

max-attendees-per-instance urn:ietf:params:xml:ns:caldav Provides a numeric value indicating the maximum number of ATTENDEE properties in any instance of a calendar object resource stored in a calendar collection. This property &MAY; be defined on any calendar collection. If defined, it &MUST; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:max-attendees-per-instance is used to specify a numeric value that indicates the maximum number of iCalendar ATTENDEE properties on any one instance of a calendar object resource stored in a calendar collection. Any attempt to store a calendar object resource with more ATTENDEE properties per instance than this value &MUST; result in an error, with the CALDAV:max-attendees-per-instance precondition () being violated. In the absence of this property, the client can assume that the server can handle any number of ATTENDEE properties in a calendar component.

PCDATA value: a numeric value (integer greater than zero)]]>

25]]>

This specification requires an additional Precondition for the PROPPATCH method. The precondition is: (CALDAV:valid-calendar-data): The time zone specified in CALDAV:calendar-timezone property &MUST; be a valid iCalendar object containing a single valid VTIMEZONE component.

Calendar collections and calendar object resources may be created by either a CalDAV client or by the CalDAV server. This specification defines restrictions and a data model that both clients and servers &MUST; adhere to when manipulating such calendar data.

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 help organize their data better. 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; however, that path segment may be "opaque" and not represent any meaningful human-readable text. 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, 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 .

]]> 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:valid-calendar-data): The time zone specified in the CALDAV:calendar-timezone property &MUST; be a valid iCalendar object containing a single valid VTIMEZONE component; (DAV:needs-privilege): The DAV:bind privilege &MUST; be granted to the current 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.

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 means exhaustive. 201 (Created) - The calendar collection resource was created in its 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 in this situation: 403 (Forbidden) - The client, for reasons the server chooses not to specify, cannot alter one of the 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) - 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; 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; and 507 (Insufficient Storage) - The server did not have sufficient space to record the 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; 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; and 507 (Insufficient Storage) - The resource does not have sufficient space to record the state of the resource after the execution of this method.

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

>> Request << Lisa's Events

Calendar restricted to events.

]]><![CDATA[]]>

]]>

>> Response <<

Clients 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 to the calendar object resource's iCalendar properties or other metadata. New calendar object resources &MUST; be created with a PUT request targeted at an unmapped URI. A PUT request targeted at a mapped URI updates an existing calendar object resource. When servers create new resources, it's not hard for the server to choose 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 resource isn't created with a name collision. However, there 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-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 "If-None-Match: *" request header ensures that the client will not inadvertently overwrite an existing resource if the last path segment turned out to already be used.

>> 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 indicated in , 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".

This specification creates additional Preconditions for PUT, COPY, and MOVE methods. These preconditions apply when a PUT operation of a calendar object resource into a calendar collection occurs, or when a COPY or MOVE operation of a calendar object resource into a calendar collection occurs, or when a COPY or MOVE operation occurs on a calendar collection. The new preconditions are: (CALDAV:supported-calendar-data): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST; be a supported media type (i.e., iCalendar) for calendar object resources; (CALDAV:valid-calendar-data): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST; be valid data for the media type being specified (i.e., &MUST; contain valid iCalendar data); (CALDAV:valid-calendar-object-resource): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST; obey all restrictions specified in (e.g., calendar object resources &MUST-NOT; contain more than one type of calendar component, calendar object resources &MUST-NOT; specify the iCalendar METHOD property, etc.); (CALDAV:supported-calendar-component): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST; contain a type of calendar component that is supported in the targeted calendar collection; (CALDAV:no-uid-conflict): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST-NOT; specify an iCalendar UID property value already in use in the targeted calendar collection or overwrite an existing calendar object resource with one that has a different UID property value. Servers &SHOULD; report the URL of the resource that is already making use of the same UID property value in the DAV:href element;

]]> (CALDAV:calendar-collection-location-ok): In a COPY or MOVE request, when the Request-URI is a calendar collection, the Destination-URI &MUST; identify a location where a calendar collection can be created; (CALDAV:max-resource-size): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST; have an octet size less than or equal to the value of the CALDAV:max-resource-size property value () on the calendar collection where the resource will be stored; (CALDAV:min-date-time): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST; have all of its iCalendar DATE or DATE-TIME property values (for each recurring instance) greater than or equal to the value of the CALDAV:min-date-time property value () on the calendar collection where the resource will be stored; (CALDAV:max-date-time): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST; have all of its iCalendar DATE or DATE-TIME property values (for each recurring instance) less than the value of the CALDAV:max-date-time property value () on the calendar collection where the resource will be stored; (CALDAV:max-instances): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST; generate a number of recurring instances less than or equal to the value of the CALDAV:max-instances property value () on the calendar collection where the resource will be stored; (CALDAV:max-attendees-per-instance): The resource submitted in the PUT request, or targeted by a COPY or MOVE request, &MUST; have a number of ATTENDEE properties on any one instance less than or equal to the value of the CALDAV:max-attendees-per-instance property value () on the calendar collection where the resource will be stored;

iCalendar provides a "standard mechanism for doing non-standard things". This extension support allows implementers to make use of non-standard components, properties, and parameters whose names are prefixed with the text "X-". Servers &MUST; support the use of non-standard components, properties, and parameters in calendar object resources stored via the PUT method. Servers may need to enforce rules for their own "private" components, properties, or parameters, so servers &MAY; reject any attempt by the client to change those or use values for those outside of any restrictions the server may have. Servers &SHOULD; ensure that any "private" components, properties, or parameters it uses follow the convention of including a vendor id in the "X-" name, as described in , e.g., "X-ABC-PRIVATE".

The DAV:getetag property &MUST; be defined and set to a strong entity tag on all calendar object resources. A response to a GET request targeted at a calendar object resource &MUST; contain an ETag response header field indicating the current value of the strong entity tag of the calendar object resource. Servers &SHOULD; return a strong entity tag (ETag header) in a PUT response when the stored calendar object resource is equivalent by octet equality to the calendar object resource submitted in the body of the PUT request. This allows clients to reliably use the returned strong entity tag for data synchronization purposes. For instance, the client can do a PROPFIND request on the stored calendar object resource and have the DAV:getetag property returned, and compare that value with the strong entity tag it received on the PUT response, and know that if they are equal, then the calendar object resource on the server has not been changed. In the case where the data stored by a server as a result of a PUT request is not equivalent by octet equality to the submitted calendar object resource, the behavior of the ETag response header is not specified here, with the exception that a strong entity tag &MUST-NOT; be returned in the response. As a result, clients may need to retrieve the modified calendar object resource (and ETag) as a basis for further changes, rather than use the calendar object resource it had sent with the PUT request.

CalDAV servers &MUST; support and adhere to the requirements of WebDAV ACL. WebDAV ACL provides a framework for an extensible set of privileges that can be applied to WebDAV collections and ordinary resources. CalDAV servers &MUST; also support the calendaring privilege defined in this section.

Calendar users often wish to allow other users to see their busy time information, without viewing the other details of the calendar components (e.g., location, summary, attendees). This allows a significant amount of privacy while still allowing other users to schedule meetings at times when the user is likely to be free. The CALDAV:read-free-busy privilege controls which calendar collections, regular collections, and calendar object resources are examined when a CALDAV:free-busy-query REPORT request is processed (see ). This privilege can be granted on calendar collections, regular collections, or calendar object resources. Servers &MUST; support this privilege on all calendar collections, regular collections, and calendar object resources.

]]> 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 DAV:read privilege being granted. Clients should note that when only the CALDAV:read-free-busy privilege has been granted on a resource, access to GET, HEAD, OPTIONS, and PROPFIND on the resource is not implied (those operations are governed by the DAV:read privilege).

This section defines an additional property for WebDAV principal resources, as defined in .

calendar-home-set urn:ietf:params:xml:ns:caldav Identifies the URL of any WebDAV collections that contain calendar collections owned by the associated principal resource. This property &SHOULD; be defined on a principal resource. If defined, it &MAY; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:calendar-home-set property is meant to allow users to easily find the calendar collections owned by the principal. Typically, users will group all the calendar collections that they own under a common collection. This property specifies the URL of collections that are either calendar collections or ordinary collections that have child or descendant calendar collections owned by the principal.

]]>

http://cal.example.com/home/bernard/calendars/ ]]>

This section defines the reports that CalDAV servers &MUST; support on calendar collections and calendar object resources. CalDAV servers &MUST; advertise support for these reports on all calendar collections and calendar object resources with the DAV:supported-report-set property, defined in . CalDAV servers &MAY; also advertise support for these reports on ordinary collections. Some of these reports allow calendar data (from possibly multiple resources) to be returned.

The REPORT method (defined in ) provides an extensible mechanism for obtaining information about one or more resources. 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. CalDAV servers &MUST; support the DAV:expand-property REPORT defined in .

Servers &MAY; support the reports defined in this document on ordinary collections (collections that are not calendar collections), in addition to calendar collections or calendar object resources. In computing responses to the reports on ordinary collections, servers &MUST; only consider calendar object resources contained in calendar collections that are targeted by the REPORT request, based on the value of the Depth request header.

iCalendar provides a way to specify DATE and DATE-TIME values that are not bound to any time zone in particular, hereafter called "floating date" and "floating time", respectively. These values are used to represent the same day, hour, minute, and second value, regardless of which time zone is being observed. For instance, the DATE value "20051111", represents November 11, 2005 in no specific time zone, while the DATE-TIME value "20051111T111100" represents November 11, 2005, at 11:11 A.M. 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 processing of calendaring REPORT requests. For the CALDAV:calendar-query REPORT, CalDAV servers &MUST; rely on the value of 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, or 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 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.

Some of the reports defined in this section can include a time range filter that is used to restrict the set of calendar object resources returned to just those that overlap the specified time range. The time range filter can be applied to a calendar component as a whole, or to specific calendar component properties with DATE or DATE-TIME value types. To determine whether a calendar object resource matches the time range filter element, the start and end times for the targeted component or property are determined and then compared to the requested time range. If there is an overlap with the requested time range, then the calendar object resource matches the filter element. The rules defined in for determining the actual start and end times of calendar components &MUST; be used, and these are fully enumerated in of this document. When such time range filtering is used, special consideration must be given to recurring calendar components, such as VEVENT and VTODO. 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.

Some of the reports defined in this section do text matches of character strings provided by the client and are compared to stored calendar data. Since iCalendar data is, by default, encoded in the UTF-8 charset and may include characters outside the US-ASCII charset range in some property and parameter values, there is a need to ensure that text matching follows well-defined rules. To deal with this, this specification makes use of the IANA Collation Registry defined in to specify collations that may be used to carry out the text comparison operations with a well-defined rule. The comparisons used in CalDAV are all "substring" matches, as per . Collations supported by the server &MUST; support "substring" match operations. CalDAV servers are &REQUIRED; to support the "i;ascii-casemap" and "i;octet" collations, as described in , and &MAY; support other collations. Servers &MUST; advertise the set of collations that they support via the CALDAV:supported-collation-set property defined on any resource that supports reports that use collations. Clients &MUST; only use collations from the list advertised by the server. In the absence of a collation explicitly specified by the client, or if the client specifies the "default" collation identifier (as defined in ), the server &MUST; default to using "i;ascii-casemap" as the collation. Wildcards (as defined in ) &MUST-NOT; be used in the collation identifier. If the client chooses a collation not supported by the server, the server &MUST; respond with a CALDAV:supported-collation precondition error response.

supported-collation-set urn:ietf:params:xml:ns:caldav Identifies the set of collations supported by the server for text matching operations. This property &MUST; be defined on any resource that supports a report that does text matching. If defined, it &MUST; be protected and &SHOULD-NOT; be returned by a PROPFIND DAV:allprop request (as defined in ). The CALDAV:supported-collation-set property contains zero or more CALDAV:supported-collation elements, which specify the collection identifiers of the collations supported by the server.

]]>

i;ascii-casemap

i;octet ]]>

Some calendaring reports defined in this document allow partial retrieval of calendar object resources. A CalDAV client can specify what information to return in the body of a calendaring REPORT request. A CalDAV client can request particular WebDAV property values, all WebDAV property values, or a list of the names of the resource's WebDAV properties. A CalDAV client can also request calendar data to be returned and specify whether all calendar components and properties should be returned, or only particular ones. See CALDAV:calendar-data in . By default, the returned calendar data will include 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". A CalDAV client that is only interested in the recurrence instances that overlap a specified time range can request to receive only the "master component", along with the "overridden components" that impact the specified time range, and thus, limit the data returned by the server (see CALDAV:limit-recurrence-set in ). An overridden component impacts a time range if its current start and end times overlap the time range, or if the original start and end times -- the ones that would have been used if the instance were not overridden -- overlap the time range, or if it affects other instances that overlap the time range. A CalDAV client with no support for recurrence properties (i.e., EXDATE, EXRULE, RDATE, and RRULE) and possibly VTIMEZONE components, or a client unwilling to perform recurrence expansion because of limited processing capability, can request to receive only the recurrence instances that overlap a specified time range as separate calendar components that each define exactly one recurrence instance (see CALDAV:expand in .) Finally, in the case of VFREEBUSY components, a CalDAV client can request to receive only the FREEBUSY property values that overlap a specified time range (see CALDAV:limit-freebusy-set in .)

Servers &MUST; support the use of non-standard component, property, or parameter names in the CALDAV:calendar-data XML element in calendaring REPORT requests to allow clients to request that non-standard components, properties, and parameters be returned in the calendar data provided in the response. Servers &MAY; support the use of non-standard component, property, or parameter names in the CALDAV:comp-filter, CALDAV:prop-filter, and CALDAV:param-filter XML elements specified in the CALDAV:filter XML element of calendaring REPORT requests. Servers &MUST; fail with the CALDAV:supported-filter precondition if a calendaring REPORT request uses a CALDAV:comp-filter, CALDAV:prop-filter, or CALDAV:param-filter XML element that makes reference to a non-standard component, property, or parameter name on which the server does not support queries.

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 that does not exist is an error and &MUST; be noted with a response XML element that 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 . The request &MAY; include a Depth header. If no Depth header is included, Depth:0 is assumed. 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 element (see ) specify a media type supported by the server for calendar object resources. (CALDAV:valid-filter): The CALDAV:filter XML element (see ) specified in the REPORT request &MUST; be valid. For instance, a CALDAV:filter cannot nest a ]]> element in a ]]> element, and a CALDAV:filter cannot nest a ]]> element in a ]]> element. (CALDAV:supported-filter): The CALDAV:comp-filter (see ), CALDAV:prop-filter (see ), and CALDAV:param-filter (see ) XML elements used in the CALDAV:filter XML element (see ) in the REPORT request only make reference to components, properties, and parameters for which queries are supported by the server, i.e., if the CALDAV:filter element attempts to reference an unsupported component, property, or parameter, this precondition is violated. Servers &SHOULD; report the CALDAV:comp-filter, CALDAV:prop-filter, or CALDAV:param-filter for which it does not provide support.

]]> (CALDAV:valid-calendar-data): The time zone specified in the REPORT request &MUST; be a valid iCalendar object containing a single valid VTIMEZONE component. (CALDAV:min-date-time): Any XML element specifying a range of time &MUST; have its start or end DATE or DATE-TIME values greater than or equal to the value of the CALDAV:min-date-time property value () on the calendar collections being targeted by the REPORT request; (CALDAV:max-date-time): Any XML element specifying a range of time &MUST; have its start or end DATE or DATE-TIME values less than or equal to the value of the CALDAV:max-date-time property value () on the calendar collections being targeted by the REPORT request; (CALDAV:supported-collation): Any XML attribute specifying a collation &MUST; specify a collation supported by the server as described in . 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.

In this example, the client requests the server to return specific components and properties of the VEVENT components that overlap the time range from January 4, 2006, at 00:00:00 A.M. UTC to January 5, 2006, at 00:00:00 A.M. UTC. In addition, the DAV:getetag property is also requested and returned as part of the response. Note that the first calendar object returned is a recurring event whose first instance lies outside the requested time range, but whose third instance does overlap the time range. Note that due to the CALDAV:calendar-data element restrictions, the DTSTAMP property in VEVENT components has not been returned, and the only property returned in the VCALENDAR object is VERSION. See for the calendar data being targeted by this example.

>> Request <<

]]>

>> Response << http://cal.example.com/bernard/work/abcd2.ics "fffff-abcd2"

BEGIN:VCALENDAR VERSION:2.0 BEGIN:VTIMEZONE LAST-MODIFIED:20040110T032845Z TZID:US/Eastern BEGIN:DAYLIGHT DTSTART:20000404T020000 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4 TZNAME:EDT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 END:DAYLIGHT BEGIN:STANDARD DTSTART:20001026T020000 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 TZNAME:EST TZOFFSETFROM:-0400 TZOFFSETTO:-0500 END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTART;TZID=US/Eastern:20060102T120000 DURATION:PT1H RRULE:FREQ=DAILY;COUNT=5 SUMMARY:Event #2 UID:00959BC664CA650E933C892C@example.com END:VEVENT BEGIN:VEVENT DTSTART;TZID=US/Eastern:20060104T140000 DURATION:PT1H RECURRENCE-ID;TZID=US/Eastern:20060104T120000 SUMMARY:Event #2 bis UID:00959BC664CA650E933C892C@example.com END:VEVENT BEGIN:VEVENT DTSTART;TZID=US/Eastern:20060106T140000 DURATION:PT1H RECURRENCE-ID;TZID=US/Eastern:20060106T120000 SUMMARY:Event #2 bis bis UID:00959BC664CA650E933C892C@example.com END:VEVENT END:VCALENDAR

HTTP/1.1 200 OK http://cal.example.com/bernard/work/abcd3.ics "fffff-abcd3"

HTTP/1.1 200 OK ]]>

In this example, the client requests the server to return VEVENT components that overlap the time range from January 3, 2006, at 00:00:00 A.M. UTC to January 5, 2006, at 00:00:00 A.M. UTC. Use of the CALDAV:limit-recurrence-set element causes the server to only return overridden recurrence components that overlap the time range specified in that element or that affect other instances that overlap the time range (e.g., in the case of a THISANDFUTURE behavior). In this example, the first overridden component in the matching resource is returned, but the second one is not. See for the calendar data being targeted by this example.

>> Request <<

]]>

>> Response << http://cal.example.com/bernard/work/abcd2.ics "fffff-abcd2"

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VTIMEZONE LAST-MODIFIED:20040110T032845Z TZID:US/Eastern BEGIN:DAYLIGHT DTSTART:20000404T020000 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4 TZNAME:EDT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 END:DAYLIGHT BEGIN:STANDARD DTSTART:20001026T020000 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 TZNAME:EST TZOFFSETFROM:-0400 TZOFFSETTO:-0500 END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTAMP:20060206T001121Z DTSTART;TZID=US/Eastern:20060102T120000 DURATION:PT1H RRULE:FREQ=DAILY;COUNT=5 SUMMARY:Event #2 UID:00959BC664CA650E933C892C@example.com END:VEVENT BEGIN:VEVENT DTSTAMP:20060206T001121Z DTSTART;TZID=US/Eastern:20060104T140000 DURATION:PT1H RECURRENCE-ID;TZID=US/Eastern:20060104T120000 SUMMARY:Event #2 bis UID:00959BC664CA650E933C892C@example.com END:VEVENT END:VCALENDAR

HTTP/1.1 200 OK http://cal.example.com/bernard/work/abcd3.ics "fffff-abcd3"

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VTIMEZONE LAST-MODIFIED:20040110T032845Z TZID:US/Eastern BEGIN:DAYLIGHT DTSTART:20000404T020000 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4 TZNAME:EDT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 END:DAYLIGHT BEGIN:STANDARD DTSTART:20001026T020000 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 TZNAME:EST TZOFFSETFROM:-0400 TZOFFSETTO:-0500 END:STANDARD END:VTIMEZONE BEGIN:VEVENT ATTENDEE;PARTSTAT=ACCEPTED;ROLE=CHAIR:mailto:cyrus@example.com ATTENDEE;PARTSTAT=NEEDS-ACTION:mailto:lisa@example.com DTSTAMP:20060206T001220Z DTSTART;TZID=US/Eastern:20060104T100000 DURATION:PT1H LAST-MODIFIED:20060206T001330Z ORGANIZER:mailto:cyrus@example.com SEQUENCE:1 STATUS:TENTATIVE SUMMARY:Event #3 UID:DC6C50A017428C5216A2F1CD@example.com X-ABC-GUID:E1CX5Dr-0007ym-Hz@example.com END:VEVENT END:VCALENDAR

HTTP/1.1 200 OK ]]>

In this example, the client requests the server to return VEVENT components that overlap the time range from January 2, 2006, at 00:00:00 A.M. UTC to January 5, 2006, at 00:00:00 A.M. UTC and to return recurring calendar components expanded into individual recurrence instance calendar components. Use of the CALDAV:expand element causes the server to only return overridden recurrence instances that overlap the time range specified in that element. See for the calendar data being targeted by this example.

>> Request <<

]]>

>> Response << http://cal.example.com/bernard/work/abcd2.ics "fffff-abcd2"

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VEVENT DTSTAMP:20060206T001121Z DTSTART:20060103T170000 DURATION:PT1H RECURRENCE-ID:20060103T170000 SUMMARY:Event #2 UID:00959BC664CA650E933C892C@example.com END:VEVENT BEGIN:VEVENT DTSTAMP:20060206T001121Z DTSTART:20060104T190000 DURATION:PT1H RECURRENCE-ID:20060104T170000 SUMMARY:Event #2 bis UID:00959BC664CA650E933C892C@example.com END:VEVENT END:VCALENDAR

HTTP/1.1 200 OK http://cal.example.com/bernard/work/abcd3.ics "fffff-abcd3"

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VEVENT ATTENDEE;PARTSTAT=ACCEPTED;ROLE=CHAIR:mailto:cyrus@example.com ATTENDEE;PARTSTAT=NEEDS-ACTION:mailto:lisa@example.com DTSTAMP:20060206T001220Z DTSTART:20060104T150000 DURATION:PT1H LAST-MODIFIED:20060206T001330Z ORGANIZER:mailto:cyrus@example.com SEQUENCE:1 STATUS:TENTATIVE SUMMARY:Event #3 UID:DC6C50A017428C5216A2F1CD@example.com X-ABC-GUID:E1CX5Dr-0007ym-Hz@example.com END:VEVENT END:VCALENDAR

HTTP/1.1 200 OK ]]>

In this example, the client requests the server to return the VFREEBUSY components that have free busy information that overlap the time range from January 2, 2006, at 00:00:00 A.M. UTC (inclusively) to January 3, 2006, at 00:00:00 A.M. UTC (exclusively). Use of the CALDAV:limit-freebusy-set element causes the server to only return the FREEBUSY property values that overlap the time range specified in that element. Note that this is not an example of discovering when the calendar owner is busy. See for the calendar data being targeted by this example.

>> Request <<

]]>

>> Response << http://cal.example.com/bernard/work/abcd8.ics "fffff-abcd8"

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:20060101T100000Z DTEND:20060108T100000Z FREEBUSY;FBTYPE=BUSY-TENTATIVE:20060102T100000Z/20060102T120000Z END:VFREEBUSY END:VCALENDAR

HTTP/1.1 200 OK ]]>

In this example, the client requests the server to return the VTODO components that have an alarm trigger scheduled in the specified time range. See for the calendar data being targeted by this example.

>> Request <<

]]>

>> Response << http://cal.example.com/bernard/work/abcd4.ics "fffff-abcd4"

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VTODO DTSTAMP:20060205T235300Z DUE;TZID=US/Eastern:20060106T120000 LAST-MODIFIED:20060205T235308Z SEQUENCE:1 STATUS:NEEDS-ACTION SUMMARY:Task #2 UID:E10BA47467C5C69BB74E8720@example.com BEGIN:VALARM ACTION:AUDIO TRIGGER;RELATED=START:-PT10M END:VALARM END:VTODO END:VCALENDAR

HTTP/1.1 200 OK ]]>

In this example, the client requests the server to return the VEVENT component that has the UID property set to "DC6C50A017428C5216A2F1CD@example.com". See for the calendar data being targeted by this example.

>> Request <<

DC6C50A017428C5216A2F1CD@example.com

]]>

>> Response << http://cal.example.com/bernard/work/abcd3.ics "fffff-abcd3"

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VTIMEZONE LAST-MODIFIED:20040110T032845Z TZID:US/Eastern BEGIN:DAYLIGHT DTSTART:20000404T020000 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4 TZNAME:EDT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 END:DAYLIGHT BEGIN:STANDARD DTSTART:20001026T020000 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 TZNAME:EST TZOFFSETFROM:-0400 TZOFFSETTO:-0500 END:STANDARD END:VTIMEZONE BEGIN:VEVENT ATTENDEE;PARTSTAT=ACCEPTED;ROLE=CHAIR:mailto:cyrus@example.com ATTENDEE;PARTSTAT=NEEDS-ACTION:mailto:lisa@example.com DTSTAMP:20060206T001220Z DTSTART;TZID=US/Eastern:20060104T100000 DURATION:PT1H LAST-MODIFIED:20060206T001330Z ORGANIZER:mailto:cyrus@example.com SEQUENCE:1 STATUS:TENTATIVE SUMMARY:Event #3 UID:DC6C50A017428C5216A2F1CD@example.com X-ABC-GUID:E1CX5Dr-0007ym-Hz@example.com END:VEVENT END:VCALENDAR

HTTP/1.1 200 OK ]]>

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

>> Request <<

mailto:lisa@example.com

NEEDS-ACTION

]]>

>> Response << http://cal.example.com/bernard/work/abcd3.ics "fffff-abcd3"

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VTIMEZONE LAST-MODIFIED:20040110T032845Z TZID:US/Eastern BEGIN:DAYLIGHT DTSTART:20000404T020000 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4 TZNAME:EDT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 END:DAYLIGHT BEGIN:STANDARD DTSTART:20001026T020000 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 TZNAME:EST TZOFFSETFROM:-0400 TZOFFSETTO:-0500 END:STANDARD END:VTIMEZONE BEGIN:VEVENT ATTENDEE;PARTSTAT=ACCEPTED;ROLE=CHAIR:mailto:cyrus@example.com ATTENDEE;PARTSTAT=NEEDS-ACTION:mailto:lisa@example.com DTSTAMP:20060206T001220Z DTSTART;TZID=US/Eastern:20060104T100000 DURATION:PT1H LAST-MODIFIED:20060206T001330Z ORGANIZER:mailto:cyrus@example.com SEQUENCE:1 STATUS:TENTATIVE SUMMARY:Event #3 UID:DC6C50A017428C5216A2F1CD@example.com X-ABC-GUID:E1CX5Dr-0007ym-Hz@example.com END:VEVENT END:VCALENDAR

HTTP/1.1 200 OK ]]>

In this example, the client requests the server to return all VEVENT components. See for the calendar data being targeted by this example.

>> Request <<

]]>

>> Response << http://cal.example.com/bernard/work/abcd1.ics "fffff-abcd1"

HTTP/1.1 200 OK http://cal.example.com/bernard/work/abcd2.ics "fffff-abcd2"

HTTP/1.1 200 OK http://cal.example.com/bernard/work/abcd3.ics "fffff-abcd3"

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VTIMEZONE LAST-MODIFIED:20040110T032845Z TZID:US/Eastern BEGIN:DAYLIGHT DTSTART:20000404T020000 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4 TZNAME:EDT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 END:DAYLIGHT BEGIN:STANDARD DTSTART:20001026T020000 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 TZNAME:EST TZOFFSETFROM:-0400 TZOFFSETTO:-0500 END:STANDARD END:VTIMEZONE BEGIN:VEVENT ATTENDEE;PARTSTAT=ACCEPTED;ROLE=CHAIR:mailto:cyrus@example.com ATTENDEE;PARTSTAT=NEEDS-ACTION:mailto:lisa@example.com DTSTAMP:20060206T001220Z DTSTART;TZID=US/Eastern:20060104T100000 DURATION:PT1H LAST-MODIFIED:20060206T001330Z ORGANIZER:mailto:cyrus@example.com SEQUENCE:1 STATUS:TENTATIVE SUMMARY:Event #3 UID:DC6C50A017428C5216A2F1CD@example.com X-ABC-GUID:E1CX5Dr-0007ym-Hz@example.com END:VEVENT END:VCALENDAR

HTTP/1.1 200 OK ]]>

In this example, the client requests the server to return all VTODO components that do not include a COMPLETED property and do not have a STATUS property value matching CANCELLED, i.e., VTODOs that still need to be worked on. See for the calendar data being targeted by this example.

>> Request <<

CANCELLED

]]>

>> Response << http://cal.example.com/bernard/work/abcd4.ics "fffff-abcd4"

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VTODO DTSTAMP:20060205T235335Z DUE;VALUE=DATE:20060104 STATUS:NEEDS-ACTION SUMMARY:Task #1 UID:DDDEEB7915FA61233B861457@example.com BEGIN:VALARM ACTION:AUDIO TRIGGER;RELATED=START:-PT10M END:VALARM END:VTODO END:VCALENDAR

HTTP/1.1 200 OK http://cal.example.com/bernard/work/abcd5.ics