LEMONADE P. Resnick Internet-Draft QUALCOMM Incorporated Expires: June 29, 2004 December 30, 2003 Internet Message Access Protocol (IMAP) CATENATE Extension draft-ietf-lemonade-catenate-01 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 June 29, 2004. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract The CATENATE extension to the Internet Message Access Protocol (IMAP) allows clients to create messages on the IMAP server which may contain a combination of new data along with parts of (or entire) messages already on the server. Using this extension, the client can catenate parts of an already existing message on to a new message without having to first download the data and then upload it back to the server. Resnick Expires June 29, 2004 [Page 1] Internet-Draft IMAP CATENATE Extension December 2003 1. Introduction The CATENATE extension to the Internet Message Access Protocol (IMAP) [1] allows the client to create a message on the server which can include the text of messages (or parts of messages) that already exist on the server without having to FETCH them and APPEND them back to the server. The CATENATE command works much like the APPEND command except that, instead of a single message literal, the command can take as arguments any combination of message literals (as described in IMAP [1]) and message URLs (as described in the IMAP URL Scheme [2] specification). The server takes all of the pieces and catenates them into the output message. There are some obvious uses for the CATENATE command. The motivating use case for this command was to provide a way for a resource-constrained client to compose a message for future delivery which contains data that already exists in that client's IMAP store. Because the client does not have to download and re-upload potentially large message parts, bandwidth and processing limitations do not have as much impact. (Mechanisms for sending the message are outside of the scope of this document.) CATENATE can also be used to copy parts of a message to another mailbox for archival purposes while getting rid of undesired parts. In environments where server storage is limited, a client could get rid of large message parts by copying over only the necessary parts and then deleting the original message. CATENATE could also be used to add data to a message such as prepending message header fields or including other data by making a copy of the original and catenating the new data. Resnick Expires June 29, 2004 [Page 2] Internet-Draft IMAP CATENATE Extension December 2003 2. The CATENATE Capability A server which supports this extension returns "CATENATE" as one of the responses to the CAPABILITY command. Resnick Expires June 29, 2004 [Page 3] Internet-Draft IMAP CATENATE Extension December 2003 3. The CATENATE command Arguments: mailbox name OPTIONAL flag parenthesized list OPTIONAL date/time string one or more message parts to catenate, specified as: message literal or message (or message part) URL Responses: no specific responses for this command Result: OK - catenate completed NO - catenate error: can't append to that mailbox, error in flags or date/time or message text, or can't fetch that data BAD - command unknown or arguments invalid The CATENATE command concatenates all of the message parts and appends them as a new message to the end of the specified mailbox. The optional flag parenthesized list and date/time string are used just as they are in the APPEND command, setting the flags and the internal date, respectively. The subsequent parameters specify the message parts that are appended sequentially to the output message. If a message literal is specified (indicated by the octet count enclosed in braces), the octets following the count are appended just as they would be with the APPEND command. If a message URL is specified, the octets of that body part are appended, as if the literal returned in a FETCH BODY response were put in place of the message part specifier. The CATENATE command does not cause the \Seen flag to be set for any catenated body part. Note: This document only describes the behavior of the CATENATE command using a message URL (as defined by [2]) which refers to a specific message or message part in the currently selected mailbox on the current IMAP server. (Because of that, the CATENATE command is valid in the selected state for purposes of this Resnick Expires June 29, 2004 [Page 4] Internet-Draft IMAP CATENATE Extension December 2003 specification.) Use of a URL that refers to anything other than a message or message part from the currently selected mailbox on the current IMAP server is outside of the scope of this document, would require an extension to this specification, and a server implementing only this specification would return NO to such a request. The client is responsible for making sure that the catenated message is in the format of an RFC 2822 [3] message. This includes inserting appropriate MIME [4] boundaries between body parts if necessary. Responses behave just as the APPEND command. If the server implements the IMAP UIDPLUS extension [5], it will also return an APPENDUID response code in the tagged OK response. Resnick Expires June 29, 2004 [Page 5] Internet-Draft IMAP CATENATE Extension December 2003 4. Formal Syntax The following syntax specification uses the Augmented Backus-Naur Form (ABNF) [6] notation. Undefined elements are defined in the formal syntax of the ABNF [6], IMAP [1], and IMAP URL [2] specifications. catenate = "CATENATE" SP mailbox [SP flag-list] [SP date-time] 1*(SP (literal / imapurl)) Figure 1 Resnick Expires June 29, 2004 [Page 6] Internet-Draft IMAP CATENATE Extension December 2003 5. Security Considerations The CATENATE extension does not raise any security considerations that are not present for the base protocol or in the use of IMAP URLs, and these issues are discussed in the IMAP [1] and IMAP URL [2] documents. Resnick Expires June 29, 2004 [Page 7] Internet-Draft IMAP CATENATE Extension December 2003 Normative References [1] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1", RFC 3501, March 2003. [2] Newman, C., "IMAP URL Scheme", RFC 2192, September 1997. [3] Resnick, P., "Internet Message Format", RFC 2822, April 2001. [4] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [5] Myers, J., "IMAP4 UIDPLUS extension", RFC 2359, June 1998. [6] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997. Author's Address Peter W. Resnick QUALCOMM Incorporated 5775 Morehouse Drive San Diego, CA 92121-1714 US Phone: +1 858 651 4478 EMail: presnick@qualcomm.com URI: http://www.qualcomm.com/~presnick/ Resnick Expires June 29, 2004 [Page 8] Internet-Draft IMAP CATENATE Extension December 2003 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. 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