Network Working Group J. Reschke Internet-Draft greenbytes Expires: April 3, 2002 October 3, 2001 Computing the CHECKIN URI in WebDAV versioning draft-reschke-deltav-compute-checkin-uri-00 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 3, 2002. Copyright Notice Copyright (C) The Internet Society (2001). All Rights Reserved. Abstract In many cases, a versioning-aware client might want to display/ include the URI of the version it's editing while it's being edited. For instance, an editor might include this as meta information, or the author of a document might want to know the URI of the version before it's checked in. A well-known example is the W3C way of referring to document versions in recommendations: it contains references to "the current version", to "this version" and to the "previous version". Something like this is currently impossible with the current draft version of WebDAV deltaV [deltaV], as the version URI is determined at the time of CHECKIN. Distribution of this document is unlimited. Please send comments to Reschke Expires April 3, 2002 [Page 1] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 the WebDAV versioning (delta-V) working group at ietf-dav- versioning@w3.org[1], which may be joined by sending a message with subject "subscribe" to ietf-dav-versioning-request@w3.org[2]. Discussions of the delta-V working group are archived at URL: http:// lists.w3.org/Archives/Public/ietf-dav-versioning/. Table of Contents 1. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Changes for CHECKOUT method (when applied to a version-controlled resource) . . . . . . . . . . . . . . . . . 5 3.1 Example for successful CHECKOUT with computed-checkin-URI . . 5 3.2 Example for successful CHECKOUT without computed-checkin-URI . 6 4. Changes for CHECKIN method (when applied to a version-controlled resource) . . . . . . . . . . . . . . . . . 7 4.1 Example for successful CHECKIN with computed-checkin-URI . . . 7 4.2 Example for failed CHECKIN with computed-checkin-URI . . . . . 8 5. Compatibility Considerations . . . . . . . . . . . . . . . . . 9 6. Internationalization Considerations . . . . . . . . . . . . . 10 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 8. Copyright . . . . . . . . . . . . . . . . . . . . . . . . . . 12 9. Intellectual Property . . . . . . . . . . . . . . . . . . . . 13 References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 14 Full Copyright Statement . . . . . . . . . . . . . . . . . . . 15 Reschke Expires April 3, 2002 [Page 2] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 1. Notational Conventions 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]. Reschke Expires April 3, 2002 [Page 3] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 2. Introduction In many cases, a versioning-aware client might want to display/ include the URI of the version it's editing while it's being edited. For instance, an editor might include this as meta information, or the author of a document might want to know the URI of the version before it's checked in. A well-known example is the W3C way of referring to document versions in recommendations: it contains references to "the current version", to "this version" and to the "previous version". Something like this is currently impossible with the current draft version of WebDAV deltaV [deltaV], as the version URI is determined at the time of CHECKIN. This specification builds on the infrastructure provided by the WebDAV Versioning Protocol, adding support for servers willing to compute an "expected CHECKIN URI" upon CHECKOUT, and using this URI at time of CHECKIN. Reschke Expires April 3, 2002 [Page 4] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 3. Changes for CHECKOUT method (when applied to a version-controlled resource) A client may ask for an "expected CHECKIN URI" upon CHECKOUT. This is done by placing DAV:compute-expected-checkin-URI as top-level element into the request body. The server is free to either ignore the request, or to return it's best guess about what the URI for a version resource created upon CHECKIN would be. The client can detect the "expected CHECKIN URI" by parsing the response body for a top-level element called DAV:expected-checkin- URI. 3.1 Example for successful CHECKOUT with computed-checkin-URI >>Request CHECKOUT /foo.html HTTP/1.1 Host: www.webdav.org Content-Type: text/xml Content-Length: xxxx >>Response HTTP/1.1 200 OK Cache-Control: no-cache Content-Type: text/xml Content-Length: xxxx http://repo.webdav.org/his/23/ver/32 In this example, the server was able to compute the "expected CHECKIN URI" and returned it in the DAV:expected-version-URI element. Reschke Expires April 3, 2002 [Page 5] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 3.2 Example for successful CHECKOUT without computed-checkin-URI >>Request CHECKOUT /foo.html HTTP/1.1 Host: www.webdav.org Content-Type: text/xml Content-Length: xxxx >>Response HTTP/1.1 200 OK Cache-Control: no-cache In this case, no response body was returned, and thus no "expected CHECKIN URI" is available. Simarily, the server may also return >>Response HTTP/1.1 200 OK Cache-Control: no-cache Content-Type: text/xml Content-Length: xxxx ...other content... where a response body is available, but it doesn't contain the DAV:expected-checkin-URI element. Reschke Expires April 3, 2002 [Page 6] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 4. Changes for CHECKIN method (when applied to a version-controlled resource) A client may submit the "expected CHECKIN URI" (obtained during CHECKOUT) upon a CHECKIN by placing it into a top-level DAV:expected- checkin-URI element in the request body. A server may o simply ignore the presence of this information or o use the information and try to checkin the resource using the "expected checkin URI" as location for the version resource. A failure to create a version resource at the "expected checkin URI" MUST cause the operation to fail with a status code of 403 (forbidden) and a response body containing the top-level element DAV:cannot-assign-expected-version-URI. In addition, a server MAY return a new "expected checkin URI" in it's response body. 4.1 Example for successful CHECKIN with computed-checkin-URI >>Request CHECKIN /foo.html HTTP/1.1 Host: www.webdav.org Content-Type: text/xml Content-Length: xxxx http://repo.webdav.org/his/23/ver/32 >>Response HTTP/1.1 201 Created Location: http://repo.webdav.org/his/23/ver/32 Cache-Control: no-cache Reschke Expires April 3, 2002 [Page 7] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 4.2 Example for failed CHECKIN with computed-checkin-URI >>Request CHECKIN /foo.html HTTP/1.1 Host: www.webdav.org Content-Type: text/xml Content-Length: xxxx http://repo.webdav.org/his/23/ver/32 >>Response HTTP/1.1 403 Forbidden Cache-Control: no-cache Content-Type: text/xml Content-Length: xxxx http://repo.webdav.org/his/23/ver/33 Reschke Expires April 3, 2002 [Page 8] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 5. Compatibility Considerations This specification does introduce new protocol elements for the request and response bodies for CHECKIN and CHECKOUT. Clients not aware of this specification will never submit the new protocol elements in a request and therefore never will see the new response elements. Servers not aware of this specification will ignore the additional two request body elements which is legal behaviour according to this protocol (indicating that the protocol extension is not available). Reschke Expires April 3, 2002 [Page 9] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 6. Internationalization Considerations This proposal builds on [deltaV], and inherits its internationalizability. Reschke Expires April 3, 2002 [Page 10] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 7. IANA Considerations This proposal does not introduce any new IANA considerations, since it does not specify any new namespaces (in the general sense), but merely uses existing ones. Reschke Expires April 3, 2002 [Page 11] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 8. Copyright To be supplied by the RFC Editor. Reschke Expires April 3, 2002 [Page 12] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 9. Intellectual Property To be supplied by the RFC Editor. Reschke Expires April 3, 2002 [Page 13] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2518] Goland, Y., Whitehead, E., Faizi, A., Carter, S. and D. Jensen, "HTTP Extensions for Distributed Authoring -- WEBDAV", RFC 2518, February 1999. [deltaV] Clemm, G., Amsden, J., Ellison, T., Kaler, C. and J. Whitehead, "Versioning Extensions to WebDAV", ID draft- ietf-deltav-versioning-18, September 2001, . [1] [2] Author's Address Julian F. Reschke greenbytes GmbH Salzmannstrasse 152 Muenster, NW 48159 Germany EMail: julian.reschke@greenbytes.de Reschke Expires April 3, 2002 [Page 14] Internet-Draft CHECKIN URI in WebDAV versioning October 2001 Full Copyright Statement Copyright (C) The Internet Society (2001). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Reschke Expires April 3, 2002 [Page 15]