Internet Draft: IMAP UNSELECT command A. Melnikov Document: draft-melnikov-imap-unselect-00.txt MessagingDirect Expires: April 2003 Intended category: Standards Track October 2002 IMAP UNSELECT command 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>. A revised version of this draft document will be submitted to the RFC editor as a Proposed Standard for the Internet Community. Discussion and suggestions for improvement are requested, and should be sent to the IMAPEXT Mailing list <ietf-imapext@imc.org>. Distribution of this draft is unlimited. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Table of Contents 0. To do.........................................................1 1. Abstract......................................................2 2. Conventions Used in this Document.............................2 3. UNSELECT command..............................................3 4. Security Considerations.......................................3 5. Formal Syntax.................................................3 6. Acknowledgments...............................................4 7. References....................................................4 8. Author's Addresses............................................4 9. Full Copyright Statement......................................5 Melnikov Expires: April 2003 [Page 1]
INTERNET DRAFT IMAP UNSELECT command October 2002 1. Abstract Certain types of IMAP clients need to release resources associated with the selected mailbox without selecting a different mailbox. While [IMAP4] provides this functionality (via a SELECT command with an invalid argument), a more clean solution is desirable. [IMAP4] defines the CLOSE command that closes the selected mailbox as well as permanently removes all messages with the \Deleted flag set. However [IMAP4] lacks a command that simply closes the mailbox without expunging it. This document defines the UNSELECT command for this purpose. A server which supports this extension indicates this with a capability name of "UNSELECT". 2. Conventions Used in this Document "C:" and "S:" in examples show lines sent by the client and server respectively. The keywords "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in this document when typed in uppercase are to be interpreted as defined in "Key words for use in RFCs to Indicate Requirement Levels" [KEYWORDS]. Melnikov Expires: April 2003 [Page 2]
INTERNET DRAFT IMAP UNSELECT command October 2002 3. UNSELECT Command Arguments: none Responses: no specific responses for this command Result: OK - unselect completed, now in authenticated state BAD - no mailbox selected, or argument supplied but none permitted The UNSELECT command frees server's resources associated with the selected mailbox and returns the server to the authenticated state. This command performs the same actions as CLOSE, except that no messages are permanently removed from the currently selected mailbox. Example: C: A341 UNSELECT S: A341 OK Unselect completed 4. Security Considerations It is belived that this extension doesn't raise any additional security concerns not already discussed in [IMAP4]. 5. Formal Syntax The following syntax specification uses the augmented Backus-Naur Form (BNF) notation as specified in [RFC-822] as modified by [IMAP4]. Non-terminals referenced but not defined below are as defined by [IMAP4]. Except as noted otherwise, all alphabetic characters are case- insensitive. The use of upper or lower case characters to define token strings is for editorial clarity only. Implementations MUST accept these strings in a case-insensitive fashion. command-select /= "UNSELECT" Melnikov Expires: April 2003 [Page 3]
INTERNET DRAFT IMAP UNSELECT command October 2002 6. Acknowledgments UNSELECT command was originally implemented in CMU IMAP server. Also, the author of the document would like to thank Vladimir Butenko and Mark Crispin for reminding that UNSELECT has to be documented. 7. References [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [IMAP4] Crispin, M., "Internet Message Access Protocol - Version 4rev1", RFC 2060, University of Washington, December 1996. 8. Author's Addresses Alexey Melnikov ACI Worldwide/MessagingDirect Address: 59 Clarendon Road, Watford, Hertfordshire, United Kingdom, WD17 1FQ Phone: +44 1923 81 2877 Email: mel@messagingdirect.com Melnikov Expires: April 2003 [Page 4]
INTERNET DRAFT IMAP UNSELECT command October 2002 9. Full Copyright Statement Copyright (C) The Internet Society (2002). 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. Melnikov Expires: April 2003 [Page 5]