This document is obsolete. Please
refer to RFC 4315.
Network Working Group J. Myers Request for Comments: 2359 Netscape Communications Category: Standards Track June 1998
IMAP4 UIDPLUS extension
Status of this Memo
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1998). All Rights Reserved.
IESG NOTE
The IMAP extension described here assumes a particular means of using IMAP to support disconnected operation. However, this means of supporting disconnected operation is not yet documented. Also, there are multiple theories about how best to do disconnected operation in IMAP, and as yet, there is no consensus on which one should be adopted as a standard.
This document is being approved as a Proposed Standard because it does not appear to have technical flaws in itelf. However, approval of this document as a Proposed Standard should not be considered an IETF endorsement of any particular means of doing disconnected operation in IMAP.
The UIDPLUS extension of the Internet Message Access Protocol [IMAP4] provides a set of features intended to reduce the amount of time and resources used by some client operations. The features in UIDPLUS are primarily intended for disconnected-use clients.
In examples, "C:" and "S:" indicate lines sent by the client and server respectively.
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in this document are to be interpreted as defined in "Key words for use in RFCs to Indicate Requirement Levels" [KEYWORDS].
The UIDPLUS extension is present in any IMAP4 server implementation which returns "UIDPLUS" as one of the supported capabilities to the CAPABILITY command. The UIDPLUS extension contains one additional command and additional data returned with successful APPEND and COPY commands.
Clients that wish to use the new command in UIDPLUS must of course first test for the presence of the extension by issuing a CAPABILITY command. Each of the features in UIDPLUS are optimizations; clients can provide the same functionality, albeit more slowly, by using commands in the base protocol. With each feature, this document recommends a fallback approach to take when the UIDPLUS extension is not supported by the server.
Result: OK - expunge completed NO - expunge failure (e.g. permission denied) BAD - command unknown or arguments invalid
Myers Standards Track [Page 2]
RFC 2359 IMAP4 UIDPLUS extension June 1998
The UID EXPUNGE command permanently removes from the currently selected mailbox all messages that both have the \Deleted flag set and have a UID that is included in the specified message set. If a message either does not have the \Deleted flag set or is has a UID that is not included in the specified message set, it is not affected.
This command may be used to ensure that a replayed EXPUNGE command does not remove any messages that have been marked as \Deleted between the time that the user requested the expunge operation and the time the server processes the command.
If the server does not support the UIDPLUS capability, the client should fall back to using the STORE command to temporarily remove the \Deleted flag from messages it does not want to remove. The client could alternatively fall back to using the EXPUNGE command, risking the unintended removal of some messages.
Successful APPEND commands return an APPENDUID response code in the tagged OK response. The APPENDUID response code contains as arguments the UIDVALIDITY of the destination mailbox and the UID assigned to the appended message.
If the server does not support the UIDPLUS capability, the client can only discover this information by selecting the destination mailbox and issuing FETCH commands.
Example: C: A003 APPEND saved-messages (\Seen) {310} C: Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST) C: From: Fred Foobar <foobar@Blurdybloop.COM> C: Subject: afternoon meeting C: To: mooch@owatagu.siam.edu C: Message-Id: <B27397-0100000@Blurdybloop.COM> C: MIME-Version: 1.0 C: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII C: C: Hello Joe, do you think we can meet at 3:30 tomorrow? C: S: A003 OK [APPENDUID 38505 3955] APPEND completed
Successful COPY and UID COPY commands return a COPYUID response code in the tagged OK response whenever at least one message was copied. The COPYUID response code contains as an argument the UIDVALIDITY of the appended-to mailbox, a message set containing the UIDs of the messages copied to the destination mailbox, in the order they were copied, and a message containing the UIDs assigned to the copied messages, in the order they were assigned. Neither of the message sets may contain extraneous UIDs or the symbol '*'.
If the server does not support the UIDPLUS capability, the client can only discover this information by selecting the destination mailbox and issuing FETCH commands.
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.
resp_code_apnd ::= "APPENDUID" SPACE nz_number SPACE uniqueid
resp_code_copy ::= "COPYUID" SPACE nz_number SPACE set SPACE set
Copyright (C) The Internet Society (1998). All Rights Reserved.
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