| Independent Submission | K. Murchison |
| Internet-Draft | CMU |
| Updates: 4918 (if approved) | September 11, 2013 |
| Intended status: Standards Track | |
| Expires: March 15, 2014 |
Use of the Prefer Header Field in Web Distributed Authoring and Versioning (WebDAV)
draft-murchison-webdav-prefer-04
This specification defines how the HTTP Prefer header field can be used by a WebDAV client to request that certain behaviors be employed by a server while constructing a response to a successful request.
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Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved.
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[I-D.snell-http-prefer] defines the HTTP Prefer request header field and the "return=minimal" preference which indicates that a client wishes for the server to return a minimal response to a successful request, but states that what constitutes an appropriate minimal response is left solely to the discretion of the server. Section 2 of this specification defines precisely what is expected of a server when constructing minimal responses to successful WebDAV [RFC4918] requests.
[I-D.snell-http-prefer] also defines the "return=representaion" preference which indicates that a client wishes for the server to include an entity representing the current state of the resource in the response to a successful request. The behavior of this preference with WebDAV [RFC4918] requests needs no further clarification, but Section 3 of this specification makes recommendations on when it should be used by clients.
Finally, Section 4 of this specifcation defines the "depth-noroot" preference that can be used with WebDAV [RFC4918] methods that support the "Depth" header field..
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
This document references XML elements types in the "DAV:" namespace outside of the context of an XML fragment. When doing so, the string "DAV:" will be prepended to the XML element type.
Some payload bodies in responses to WebDAV [RFC4918] requests, such as 207 (Multi-Status) [RFC4918] responses, can be quite verbose or even unnecessary at times. This specification defines how the Prefer [I-D.snell-http-prefer] request header field, in conjunction with its "return=minimal" preference, can be used by clients to reduce the verbosity of such responses by requesting that the server omit those portions of the response that can be inferred by their absence.
When a PROPFIND [RFC4918] method request contains a Prefer [I-D.snell-http-prefer] header field with a preference of "return=minimal", the server SHOULD omit all DAV:propstat XML elements containing a DAV:status XML element of value 404 (Not Found) [I-D.ietf-httpbis-p2-semantics] from the 207 (Multi-Status) [RFC4918] response. If the omission of such a DAV:propstat element would result in a DAV:response XML element containing zero DAV:propstat elements, then the server MUST substitute a DAV:propstat element consisting of an empty DAV:prop element and a DAV:status element of value 200 (OK) [I-D.ietf-httpbis-p2-semantics] in its place.
If the server honors and applies the return=minimal preference to the processing of a PROPFIND request as described above, the server SHOULD include a Preference-Applied [I-D.snell-http-prefer] header field containing the "return=minimal" token in the response.
This example tries to fetch an unknown property from a CARDDAV:addressbook [RFC6352] collection.
>> Request <<
PROPFIND /container/ HTTP/1.1
Host: carddav.example.com
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="UTF-8"?>
<D:propfind xmlns:D="DAV:" xmlns:X="http://ns.example.com/foobar/">
<D:prop>
<D:resourcetype/>
<X:foobar/>
</D:prop>
</D:propfind>
>> Response <<
HTTP/1.1 207 Multi-Status
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:" xmlns:X="http://ns.example.com/foobar/"
xmlns:C="urn:ietf:params:xml:ns:carddav">
<D:response>
<D:href>/container/</D:href>
<D:propstat>
<D:prop>
<D:resourcetype>
<D:collection/>
<C:addressbook/>
</D:resourcetype>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
<D:propstat>
<D:prop>
<X:foobar/>
</D:prop>
<D:status>HTTP/1.1 404 Not Found</D:status>
</D:propstat>
</D:response>
</D:multistatus>
This example tries to fetch an unknown property from a CARDDAV:addressbook [RFC6352] collection.
>> Request <<
PROPFIND /container/ HTTP/1.1
Host: carddav.example.com
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
Prefer: return=minimal
<?xml version="1.0" encoding="UTF-8"?>
<D:propfind xmlns:D="DAV:" xmlns:X="http://ns.example.com/foobar/">
<D:prop>
<D:resourcetype/>
<X:foobar/>
</D:prop>
</D:propfind>
>> Response <<
HTTP/1.1 207 Multi-Status
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
Preference-Applied: return=minimal
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:carddav">
<D:response>
<D:href>/container/</D:href>
<D:propstat>
<D:prop>
<D:resourcetype>
<D:collection/>
<C:addressbook/>
</D:resourcetype>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
This example tries to fetch an unknown property from a CARDDAV:addressbook [RFC6352] collection.
>> Request <<
PROPFIND /container/ HTTP/1.1
Host: carddav.example.com
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
Prefer: return=minimal
<?xml version="1.0" encoding="UTF-8"?>
<D:propfind xmlns:D="DAV:" xmlns:X="http://ns.example.com/foobar/">
<D:prop>
<X:foobar/>
</D:prop>
</D:propfind>
>> Response <<
HTTP/1.1 207 Multi-Status
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
Preference-Applied: return=minimal
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>/container/</D:href>
<D:propstat>
<D:prop/>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
When a REPORT [RFC3253] method request, whose report type results in a 207 (Multi-Status) [RFC4918] response, contains a Prefer header field with a preference of "return=minimal", the server SHOULD omit all DAV:propstat XML elements containing a DAV:status XML element of value 404 (Not Found) [I-D.ietf-httpbis-p2-semantics] from the 207 (Multi-Status) [RFC4918] response. If the omission of such a DAV:propstat element would result in a DAV:response XML element containing zero DAV:propstat elements, then the server MUST substitute a DAV:propstat element consisting of an empty DAV:prop element and a DAV:status element of value 200 (OK) [I-D.ietf-httpbis-p2-semantics] in its place.
If the server honors and applies the return=minimal preference to the processing of a REPORT request as described above, the server SHOULD include a Preference-Applied [I-D.snell-http-prefer] header field containing the "return=minimal" token in the response.
This example uses the CALDAV:calendar-multiget [RFC4791] REPORT type.
>> Request <<
REPORT /murch/work/ HTTP/1.1
Host: caldav.example.com
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-multiget xmlns:C="urn:ietf:params:xml:ns:caldav"
xmlns:D="DAV:"
xmlns:X="http://ns.example.com/foobar/">
<D:prop>
<D:getetag/>
<X:foobar/>
</D:prop>
<D:href>/murch/work/abc.ics</D:href>
<D:href>/murch/work/qrs.ics</D:href>
<D:href>/murch/work/xyz.ics</D:href>
</C:calendar-multiget>
>> Response <<
HTTP/1.1 207 Multi-Status
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:"
xmlns:X="http://ns.example.com/foobar/">
<D:response>
<D:href>/murch/work/abc.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>"jahsd823ru"</D:getetag>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
<D:propstat>
<D:prop>
<X:foobar/>
</D:prop>
<D:status>HTTP/1.1 404 Not Found</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>/murch/work/qrs.ics</D:href>
<D:status>HTTP/1.1 404 Not Found</D:status>
</D:response>
<D:response>
<D:href>/murch/work/xyz.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>"p08ulkj"</D:getetag>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
<D:propstat>
<D:prop>
<X:foobar/>
</D:prop>
<D:status>HTTP/1.1 404 Not Found</D:status>
</D:propstat>
</D:response>
</D:multistatus>
This example uses the CALDAV:calendar-multiget [RFC4791] REPORT type.
>> Request <<
REPORT /murch/work/ HTTP/1.1
Host: caldav.example.com
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
Prefer: return=minimal
<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-multiget xmlns:C="urn:ietf:params:xml:ns:caldav"
xmlns:D="DAV:"
xmlns:X="http://ns.example.com/foobar/">
<D:prop>
<D:getetag/>
<X:foobar/>
</D:prop>
<D:href>/murch/work/abc.ics</D:href>
<D:href>/murch/work/qrs.ics</D:href>
<D:href>/murch/work/xyz.ics</D:href>
</C:calendar-multiget>
>> Response <<
HTTP/1.1 207 Multi-Status
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
Preference-Applied: return=minimal
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>/murch/work/abc.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>"jahsd823ru"</D:getetag>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>/murch/work/qrs.ics</D:href>
<D:status>HTTP/1.1 404 Not Found</D:status>
</D:response>
<D:response>
<D:href>/murch/work/xyz.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>"p08ulkj"</D:getetag>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
When a PROPPATCH [RFC4918] request contains a Prefer [I-D.snell-http-prefer] header field with a preference of "return=minimal", and all instructions are processed successfully, the server SHOULD return a 200 (OK) [I-D.ietf-httpbis-p2-semantics] response with an empty (zero-length) message body instead of a 207 (Multi-Status) [RFC4918] response.
>> Request <<
PROPPATCH /container/ HTTP/1.1
Host: webdav.example.com
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8"?>
<D:propertyupdate xmlns:D="DAV:">
<D:set>
<D:prop>
<D:displayname>My Container</D:displayname>
</D:prop>
</D:set>
</D:propertyupdate>
>> Response <<
HTTP/1.1 207 Multi-Status
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>/container/</D:href>
<D:propstat>
<D:prop>
<D:displayname/>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
>> Request <<
PROPPATCH /container/ HTTP/1.1
Host: webdav.example.com
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
Prefer: return=minimal
<?xml version="1.0" encoding="utf-8"?>
<D:propertyupdate xmlns:D="DAV:">
<D:set>
<D:prop>
<D:displayname>My Container</D:displayname>
</D:prop>
</D:set>
</D:propertyupdate>
>> Response <<
HTTP/1.1 200 OK Content-Length: 0 Preference-Applied: return=minimal
Both the MKCALENDAR [RFC4791] and Extended MKCOL [RFC5689] specifications indicate that a server MAY return a message body in response to a successful request. This specification explicitly defines the intended behavior in the presence of the Prefer [I-D.snell-http-prefer] header field.
When a MKCALENDAR or an Extended MKCOL request contains a Prefer header field with a preference of "return=minimal", and the collection is created with all requested properties being set successfully, the server SHOULD return a 201 (Created) [I-D.ietf-httpbis-p2-semantics] response with an empty (zero-length) message body.
>> Request <<
MKCOL /container/ HTTP/1.1
Host: webdav.example.com
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8"?>
<D:mkcol xmlns:D="DAV:">
<D:set>
<D:prop>
<D:displayname>My Container</D:displayname>
</D:prop>
</D:set>
</D:mkcol>
>> Response <<
HTTP/1.1 201 Created
Cache-Control: no-cache
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8"?>
<D:mkcol-response xmlns:D="DAV:">
<D:propstat>
<D:prop>
<D:displayname/>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:mkcol-response>
>> Request <<
MKCOL /container/ HTTP/1.1
Host: webdav.example.com
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
Prefer: return=minimal
<?xml version="1.0" encoding="utf-8"?>
<D:mkcol xmlns:D="DAV:">
<D:set>
<D:prop>
<D:displayname>My Container</D:displayname>
</D:prop>
</D:set>
</D:mkcol>
>> Response <<
HTTP/1.1 201 Created Cache-Control: no-cache Content-Length: 0 Preference-Applied: return=minimal
The PUT, COPY, MOVE, [RFC4918] and POST [RFC5995] methods can be used to create or update a resource. In some instances, such as with CalDAV Scheduling [RFC6638], the created or updated resource representation may differ from the representation sent in the body of the request or referenced by the effective request URI. In cases where the client would normally issue a subsquent GET request to retrieve the current representation of the resource, the client SHOULD instead include a Prefer header field with the "return=representation" preference in the PUT, COPY, MOVE, or POST request. By doing this, the client can coalesce the create/update and retrieve operations into one round-trip rather than two. An additional benefit of using "return=representation" in such a request is that the client will know that any changes to the resource were produced by the server rather than a concurrent client, thus providing a level of atomicity to the operation.
>> Request <<
POST /murch/work;add-member/ HTTP/1.1 Host: caldav.example.com Content-Type: text/calendar; charset=utf-8 Content-Length: xxxx BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VEVENT UID:CD87465FA SEQUENCE:0 DTSTAMP:20120602T185254Z DTSTART:20120602T160000Z DTEND:20120602T170000Z TRANSP:OPAQUE SUMMARY:Lunch ORGANIZER;CN="Ken Murchison":mailto:murch@example.com ATTENDEE;CN="Ken Murchison";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED: mailto:murch@example.com ATTENDEE;CN="John Doe";CUTYPE=INDIVIDUAL;PARTSTAT =NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:jdoe@ example.com END:VEVENT END:VCALENDAR
>> Response <<
HTTP/1.1 201 Created Location: /murch/work/abc.ics Content-Length: 0 ETag: "nahduyejc" Schedule-Tag: "jfd84hgbcn"
>> Request <<
GET /murch/work/abc.ics HTTP/1.1 Host: caldav.example.com
>> Response <<
HTTP/1.1 200 OK Content-Type: text/calendar; charset=utf-8 Content-Length: xxxx ETag: "nahduyejc" Schedule-Tag: "jfd84hgbcn" BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Server//EN BEGIN:VEVENT UID:CD87465FA SEQUENCE:0 DTSTAMP:20120602T185300Z DTSTART:20120602T160000Z DTEND:20120602T170000Z TRANSP:OPAQUE SUMMARY:Lunch ORGANIZER;CN="Ken Murchison":mailto:murch@example.com ATTENDEE;CN="Ken Murchison";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED: mailto:murch@example.com ATTENDEE;CN="John Doe";CUTYPE=INDIVIDUAL;PARTSTAT =NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE;SCHEDULE-STATUS= 1.2:mailto:jdoe@example.com END:VEVENT END:VCALENDAR
>> Request <<
POST /murch/work;add-member/ HTTP/1.1 Host: caldav.example.com Content-Type: text/calendar; charset=utf-8 Content-Length: xxxx Prefer: return=representation BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Client//EN BEGIN:VEVENT UID:CD87465FA SEQUENCE:0 DTSTAMP:20120602T185254Z DTSTART:20120602T160000Z DTEND:20120602T170000Z TRANSP:OPAQUE SUMMARY:Lunch ORGANIZER;CN="Ken Murchison":mailto:murch@example.com ATTENDEE;CN="Ken Murchison";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED: mailto:murch@example.com ATTENDEE;CN="John Doe";CUTYPE=INDIVIDUAL;PARTSTAT =NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:jdoe@ example.com END:VEVENT END:VCALENDAR
>> Response <<
HTTP/1.1 201 Created Location: /murch/work/abc.ics Content-Type: text/calendar; charset=utf-8 Content-Length: xxxx Content-Location: /murch/work/abc.ics ETag: "nahduyejc" Schedule-Tag: "jfd84hgbcn" Preference-Applied: return=representation BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Example Corp.//CalDAV Server//EN BEGIN:VEVENT UID:CD87465FA SEQUENCE:0 DTSTAMP:20120602T185300Z DTSTART:20120602T160000Z DTEND:20120602T170000Z TRANSP:OPAQUE SUMMARY:Lunch ORGANIZER;CN="Ken Murchison":mailto:murch@example.com ATTENDEE;CN="Ken Murchison";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED: mailto:murch@example.com ATTENDEE;CN="John Doe";CUTYPE=INDIVIDUAL;PARTSTAT =NEEDS-ACTION;ROLE=REQ-PARTICIPANT;RSVP=TRUE;SCHEDULE-STATUS= 1.2:mailto:jdoe@example.com END:VEVENT END:VCALENDAR
The "depth-noroot" preference indicates that the client wishes for the server to exclude the target (root) resource from processing by the WebDAV method and only apply the WebDAV method to the target resource's subordinate resources.
depth-noroot = "depth-noroot"
This preference is only intended to be used with WebDAV methods whose definitions explicitly provide support for the Depth [RFC4918] header field. Furthermore, this preference only applies when the Depth header field has a value of "1" or "infinity" (either implicitly or explicitly).
The "depth-noroot" preference MAY be used in conjunction with the "return=minimal" preference in a single request.
This example fetches the DAV:sync-token [RFC6578] property for a collection and its child collections.
>> Request <<
PROPFIND /murch/ HTTP/1.1
Host: dav.example.com
Content-Type: text/xml
Content-Length: xxx
Depth: 1
<?xml version="1.0" encoding="UTF-8"?>
<D:propfind xmlns:D="DAV:">
<D:prop>
<D:sync-token/>
</D:prop>
</D:propfind>
>> Response <<
HTTP/1.1 207 Multi-Status
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>/murch/</D:href>
<D:propstat>
<D:prop>
<D:sync-token>http://example.com/ns/sync/2216-2</D:sync-token>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>/murch/work/</D:href>
<D:propstat>
<D:prop>
<D:sync-token>http://example.com/ns/sync/2136-34</D:sync-token>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>/murch/home/</D:href>
<D:propstat>
<D:prop>
<D:sync-token>http://example.com/ns/sync/2141-19</D:sync-token>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
This example fetches the DAV:sync-token [RFC6578] property for just the child collections.
>> Request <<
PROPFIND /murch/ HTTP/1.1
Host: dav.example.com
Content-Type: text/xml
Content-Length: xxx
Depth: 1
Prefer: depth-noroot
<?xml version="1.0" encoding="UTF-8"?>
<D:propfind xmlns:D="DAV:">
<D:prop>
<D:sync-token/>
</D:prop>
</D:propfind>
>> Response <<
HTTP/1.1 207 Multi-Status
Content-Type: application/xml; charset=utf-8
Content-Length: xxxx
Preference-Applied: depth-noroot
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>/murch/work/</D:href>
<D:propstat>
<D:prop>
<D:sync-token>http://example.com/ns/sync/2136-34</D:sync-token>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>/murch/home/</D:href>
<D:propstat>
<D:prop>
<D:sync-token>http://example.com/ns/sync/2141-19</D:sync-token>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
[RFC Editor: before publication please remove this section and the reference to [RFC6982]]
This section records the status of known implementations of the protocol defined by this specification at the time of posting of this Internet-Draft, and is based on a proposal described in [RFC6982]. The description of implementations in this section is intended to assist the IETF in its decision processes in progressing drafts to RFCs. Please note that the listing of any individual implementation here does not imply endorsement by the IETF. Furthermore, no effort has been spent to verify the information presented here that was supplied by IETF contributors. This is not intended as, and must not be construed to be, a catalog of available implementations or their features. Readers are advised to note that other implementations may exist.
According to [RFC6982], "this will allow reviewers and working groups to assign due consideration to documents that have the benefit of running code, which may serve as evidence of valuable experimentation and feedback that have made the implemented protocols more mature. It is up to the individual working groups to use this information as they see fit".
The open source Cyrus project is a highly scalable enterprise mail system which also supports calendaring and contacts. This beta level CalDAV/CardDAV implementation supports all of the preferences described in this document and successfully interoperates with the CalDAVTester and aCal client implementations described below. This implementation is freely distributable under a BSD style license from Computing Services at Carnegie Mellon University.
The open source Calendar and Contacts Server project is a standards-compliant server implementing the CalDAV and CardDAV protocols. This production level implementation supports all of the preferences described in this document and successfully interoperates with the CalDAVTester client implementation described below. This implementation is freely distributable under the terms of the Apache License, Version 2.0.
Bedework is an open-source enterprise calendar system that supports public, personal, and group calendaring. This production level implementation supports the "return=minimal" preference described in this document and successfully interoperates with the CalDAVTester client implementation described below. This implementation is freely distributable under the Jasig Licensing Policy.
DAViCal is a server for calendar sharing using the CalDAV protocol. This production level implementation supports the "return=minimal" preference described in this document and successfully interoperates with the CalDAVTester client implementation described below. This implementation is Free Software distributable under the General Public License.
aCal is an open source calendar client for Android which uses the CalDAV standard for communication. This implementation makes some use of each of the preferences described in this document and successfully interoperates with the Cyrus server implementation described above. This implementation is freely distributable under the General Public License.
CalDAVTester is an open source test and performance application designed to work with CalDAV and/or CardDAV servers and tests various aspects of their protocol handling as well as performance. This widely used implementation supports all of the preferences described in this document and successfully interoperates with the server implementations described above. This implementation is freely distributable under the terms of the Apache License, Version 2.0.
No new security considerations are introduced by use of the Prefer header field with WebDAV request methods, beyond those discussed in [I-D.snell-http-prefer] and those already inherent in those methods.
The following preference is to be added to the Preferences Registry defined in [I-D.snell-http-prefer].
The author would like to thank the following individuals for contributing their ideas and support for writing this specification: Cyrus Daboo, Helge Hess, Andrew McMillan, and Arnaud Quillaud.
The author 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.
| [RFC6352] | Daboo, C., "CardDAV: vCard Extensions to Web Distributed Authoring and Versioning (WebDAV)", RFC 6352, August 2011. |
| [RFC6578] | Daboo, C. and A. Quillaud, "Collection Synchronization for Web Distributed Authoring and Versioning (WebDAV)", RFC 6578, March 2012. |
| [RFC6638] | Daboo, C. and B. Desruisseaux, "Scheduling Extensions to CalDAV", RFC 6638, June 2012. |
| [RFC6982] | Sheffer, Y. and A. Farrel, "Improving Awareness of Running Code: The Implementation Status Section", RFC 6982, July 2013. |
| [MSDN.aa563501] | Microsoft Developer Network, "Brief Header", June 2006. |
| [MSDN.aa580336] | Microsoft Developer Network, "PROPFIND Method", June 2006. |
| [MSDN.aa493854] | Microsoft Developer Network, "PROPPATCH Method", June 2006. |
| [MSDN.aa563950] | Microsoft Developer Network, "Depth Header", June 2006. |
This document is based heavily on the Brief [MSDN.aa563501] and extended Depth [MSDN.aa563950] request header fields. The behaviors described in Section 2.1 and Section 2.3 are identical to those provided by the Brief header field when used with the PROPFIND [MSDN.aa580336] and PROPPATCH [MSDN.aa493854] methods respectively. The behavior described in Section 4 is identical to that provided by the "1,noroot" [MSDN.aa563950] and "infinity,noroot" [MSDN.aa563950] Depth header field values.
Authors are encouraged to implement the Brief header field functionality in conjunction with this specification to further promote interoperability with products that use the Brief header field exclusively.
[RFC Editor: before publication please remove this section]
from:
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>/container/</D:href>
<D:status>HTTP/1.1 200 OK</D:status>
</D:response>
</D:multistatus>
to the slightly more verbose:
<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response>
<D:href>/container/</D:href>
<D:propstat>
<D:prop/>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>