Internet Message Access Protocol (IMAP) - MOVE Extension
RFC 6851

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Internet Engineering Task Force (IETF)                    A. Gulbrandsen
Request for Comments: 6851
Category: Standards Track                                  N. Freed, Ed.
ISSN: 2070-1721                                                   Oracle
                                                            January 2013

        Internet Message Access Protocol (IMAP) - MOVE Extension

Abstract

   This document defines an IMAP extension consisting of two new
   commands, MOVE and UID MOVE, that are used to move messages from one
   mailbox to another.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6851.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Gulbrandsen & Freed          Standards Track                    [Page 1]
RFC 6851                  IMAP - MOVE Extension             January 2013

1.  Introduction

   This document defines an IMAP [RFC3501] extension to facilitate
   moving messages from one mailbox to another.  This is accomplished by
   defining a new MOVE command and extending the UID command to allow
   UID MOVE.

   A move function is not provided in the base IMAP specification, so
   clients have instead had to use a combination of the COPY, STORE, and
   EXPUNGE commands to perform this very common operation.

   Implementors have long pointed out some shortcomings with this
   approach.  Because the moving of a message is not an atomic process,
   interruptions can leave messages in intermediate states.  Because
   multiple clients can be accessing the mailboxes at the same time,
   clients can see messages in intermediate states even without
   interruptions.  If the source mailbox contains other messages that
   are flagged for deletion, the third step can have the side effect of
   expunging more than just the set of moved messages.  Additionally,
   servers with certain types of back-end message stores might have
   efficient ways of moving messages, which don't involve the actual
   copying of data.  Such efficiencies are often not available to the
   COPY/STORE/EXPUNGE process.

   The MOVE extension is present in any IMAP implementation that returns
   "MOVE" as one of the supported capabilities to the CAPABILITY
   command.

2.  Conventions Used in This Document

   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].

   Formal syntax is specified using ABNF [RFC5234].

   Example lines prefaced by "C:" are sent by the client and ones
   prefaced by "S:" by the server.

Gulbrandsen & Freed          Standards Track                    [Page 2]
RFC 6851                  IMAP - MOVE Extension             January 2013

3.  MOVE and UID MOVE

3.1.  MOVE Command

   Arguments: sequence set
              mailbox name

   Responses: no specific responses for this command

   Result: OK - move completed

           NO - move error: can't move those messages or to that name

           BAD - command unknown or arguments invalid

3.2.  UID MOVE Command

   This extends the first form of the UID command (see [RFC3501],
   Section 6.4.8) to add the MOVE command defined above as a valid
   argument.

3.3.  Semantics of MOVE and UID MOVE

   The MOVE command takes two arguments: a message set (sequence numbers
   for MOVE, UIDs for UID MOVE) and a named mailbox.  Each message
   included in the set is moved, rather than copied, from the selected
   (source) mailbox to the named (target) mailbox.

   This means that a new message is created in the target mailbox with a
   new UID, the original message is removed from the source mailbox, and
   it appears to the client as a single action.  This has the same
   effect for each message as this sequence:

   1.  [UID] COPY