draft-ietf-extra-imap-replace-03.txt   rfc8508.txt 
Network Working Group S. Brandt Internet Engineering Task Force (IETF) S. Brandt
Internet-Draft Verizon Request for Comments: 8508 Verizon
Intended status: Standards Track October 25, 2018 Category: Standards Track January 2019
Expires: April 28, 2019 ISSN: 2070-1721
IMAP REPLACE Extension IMAP REPLACE Extension
draft-ietf-extra-imap-replace-03
Abstract Abstract
This document defines an IMAP extension which can be used to replace This document defines an IMAP extension that can be used to replace
an existing message in a message store with a new message. Message an existing message in a message store with a new message. Message
replacement is a common operation for clients that automatically save replacement is a common operation for clients that automatically save
drafts or notes as a user composes them. drafts or notes as a user composes them.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on April 28, 2019. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8508.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Conventions Used in This Document . . . . . . . . . . . . . . 2 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. REPLACE and UID REPLACE . . . . . . . . . . . . . . . . . . . 3 3. REPLACE and UID REPLACE . . . . . . . . . . . . . . . . . . . 3
3.1. Advertising Support for REPLACE . . . . . . . . . . . . . 3 3.1. Advertising Support for REPLACE . . . . . . . . . . . . . 3
3.2. REPLACE Command . . . . . . . . . . . . . . . . . . . . . 3 3.2. REPLACE Command . . . . . . . . . . . . . . . . . . . . . 3
3.3. UID REPLACE Command . . . . . . . . . . . . . . . . . . . 4 3.3. UID REPLACE Command . . . . . . . . . . . . . . . . . . . 4
3.4. Semantics of REPLACE and UID REPLACE . . . . . . . . . . 5 3.4. Semantics of REPLACE and UID REPLACE . . . . . . . . . . 5
3.5. IMAP State Diagram Impacts . . . . . . . . . . . . . . . 6 3.5. IMAP State Diagram Impacts . . . . . . . . . . . . . . . 6
4. Interaction with other extensions . . . . . . . . . . . . . . 6 4. Interaction with Other Extensions . . . . . . . . . . . . . . 6
4.1. RFC 4314, ACL . . . . . . . . . . . . . . . . . . . . . . 6 4.1. ACL . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.2. RFC 4469, CATENATE . . . . . . . . . . . . . . . . . . . 6 4.2. CATENATE . . . . . . . . . . . . . . . . . . . . . . . . 6
4.3. RFC 4315, UIDPLUS . . . . . . . . . . . . . . . . . . . . 8 4.3. UIDPLUS . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.4. RFC 6785, IMAP Events in Sieve . . . . . . . . . . . . . 8 4.4. IMAP Events in Sieve . . . . . . . . . . . . . . . . . . 8
4.5. RFC 7162, CONDSTORE/QRESYNC . . . . . . . . . . . . . . . 8 4.5. CONDSTORE/QRESYNC . . . . . . . . . . . . . . . . . . . . 8
4.6. RFC 8474, OBJECTID . . . . . . . . . . . . . . . . . . . 8 4.6. OBJECTID . . . . . . . . . . . . . . . . . . . . . . . . 8
4.7. RFC 3502, MULTIAPPEND . . . . . . . . . . . . . . . . . . 8 4.7. MULTIAPPEND . . . . . . . . . . . . . . . . . . . . . . . 8
5. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 8.1. Normative References . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . 9 8.2. Informative References . . . . . . . . . . . . . . . . . 10
9.2. Informative References . . . . . . . . . . . . . . . . . 10 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 11
9.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Conventions Used in This Document 1. Overview
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [1] [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Formal syntax is defined by [RFC5234].
Example lines prefaced by "C:" are sent by the client and ones
prefaced by "S:" by the server.
2. Overview
This document defines an IMAP [RFC3501] extension to facilitate This document defines an IMAP ([RFC3501]) extension to facilitate the
replacing an existing message with a new one. This is accomplished replacement of an existing message with a new one. This is
by defining a new REPLACE command and extending the UID command to accomplished by defining a new REPLACE command and extending the
allow UID REPLACE. Unique Identifier (UID) command to allow UID REPLACE.
Since there is no replace function in the base IMAP specification, Since there is no replace function in the base IMAP specification,
clients have instead had to use a combination of three separate clients have instead had to use a combination of three separate
commands issued in serial fashion; APPEND, STORE, EXPUNGE. commands issued in serial fashion; APPEND, STORE, and EXPUNGE.
Pipelining of these three commands is not recommended since failure Pipelining of these three commands is not recommended since failure
of any individual command should prevent subsequent commands from of any individual command should prevent subsequent commands from
being executed lest the original message version be lost. being executed lest the original message version be lost.
Because of the non-atomic nature of the existing sequence, Because of the non-atomic nature of the existing sequence,
interruptions can leave messages in intermediate states which can be interruptions can leave messages in intermediate states that can be
seen and acted upon by other clients. Such interruptions can also seen and acted upon by other clients. Such interruptions can also
strand older revisions of messages, thereby forcing the user to strand older revisions of messages, thereby forcing the user to
manually clean up multiple revisions of the same message in order to manually clean up multiple revisions of the same message in order to
avoid wasteful quota consumption. Additionally, the existing avoid wasteful quota consumption. Additionally, the existing
sequence can fail on APPEND due to an over-quota condition even sequence can fail on APPEND due to an over-quota condition even
though the subsequent STORE/EXPUNGE would free up enough space for though the subsequent STORE/EXPUNGE would free up enough space for
the newly revised message. And finally, server efficiencies may be the newly revised message. And finally, server efficiencies may be
possible with a single logical message replacement operation as possible with a single logical message replacement operation as
compared to the existing APPEND/STORE/EXPUNGE sequence. compared to the existing APPEND/STORE/EXPUNGE sequence.
In its simplest form, the REPLACE command is a single-command In its simplest form, the REPLACE command is a single-command
encapsulation of APPEND, STORE +flags \DELETED and UID EXPUNGE for a encapsulation of APPEND, STORE +flags \DELETED, and UID EXPUNGE for a
message, except that it avoids any of the quota implications or message, except that it avoids any of the quota implications or
intermediate states associated with the 3 command sequence. Server intermediate states associated with the three-command sequence.
developers are encouraged to implement REPLACE as an atomic operation Server developers are encouraged to implement REPLACE as an atomic
to simplify error handling, minimize operational concerns, and reduce operation to simplify error handling, minimize operational concerns,
potential security problems. For systems where this is not possible, and reduce potential security problems. For systems where this is
communication with the requesting client must ensure no confusion of not possible, communication with the requesting client must ensure no
message store state. A server MUST NOT generate a response code for confusion of message store state. A server MUST NOT generate a
the STORE +flags \DELETED portion of the sequence. Additionally, response code for the STORE +flags \DELETED portion of the sequence.
servers supporting the REPLACE command MUST NOT infer any inheritance Additionally, servers supporting the REPLACE command MUST NOT infer
of content, flags, or annotations from the message being replaced. any inheritance of content, flags, or annotations from the message
being replaced.
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Formal syntax is defined by [RFC5234].
Example lines prefaced by "C:" are sent by the client, and ones
prefaced by "S:" are sent by the server.
3. REPLACE and UID REPLACE 3. REPLACE and UID REPLACE
3.1. Advertising Support for REPLACE 3.1. Advertising Support for REPLACE
Servers that implement the REPLACE extension will return "REPLACE" as Servers that implement the REPLACE extension will return "REPLACE" as
one of the supported capabilities in the CAPABILITY command response. one of the supported capabilities in the CAPABILITY command response.
3.2. REPLACE Command 3.2. REPLACE Command
Arguments: message sequence number Arguments: message sequence number
mailbox name mailbox name
OPTIONAL flag parenthesized list OPTIONAL flag parenthesized list
OPTIONAL date/time string OPTIONAL date/time string
message literal message literal
Responses: no specific responses for this command Responses: no specific responses for this command
Result: OK - replace completed Result: OK - replace completed
NO - replace error; can't remove specified message NO - replace error; can't remove specified message
or can't add new message content or can't add new message content
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
Example: Example:
C: A003 REPLACE 4 Drafts (\Seen \Draft) {312} C: A003 REPLACE 4 Drafts (\Seen \Draft) {312}
S: + Ready for literal data S: + Ready for literal data
C: Date: Thu, 1 Jan 2015 00:05:00 -0500 (EST) C: Date: Thu, 1 Jan 2015 00:05:00 -0500 (EST)
C: From: Fritz Schmidt <fritz.ze@example.org> C: From: Fritz Schmidt <fritz.ze@example.org>
skipping to change at page 4, line 37 skipping to change at page 4, line 29
C: C:
C: Just saw the best fireworks show. Wish you were here. C: Just saw the best fireworks show. Wish you were here.
C: C:
S: * OK [APPENDUID 1 2000] Replacement Message ready S: * OK [APPENDUID 1 2000] Replacement Message ready
S: * 5 EXISTS S: * 5 EXISTS
S: * 4 EXPUNGE S: * 4 EXPUNGE
S: A003 OK Replace completed S: A003 OK Replace completed
3.3. UID REPLACE Command 3.3. UID REPLACE Command
This extends the first form of the UID command (see [RFC3501] This extends the first form of the UID command (see Section 6.4.8 of
Section 6.4.8) to add the REPLACE command defined above as a valid [RFC3501]) to add the REPLACE command defined above as a valid
argument. This form of REPLACE uses a UID rather than sequence argument. This form of REPLACE uses a UID rather than a sequence
number as its first parameter. number as its first parameter.
Example: Example:
C: A004 UID REPLACE 2000 Drafts (\Seen \Draft) {350} C: A004 UID REPLACE 2000 Drafts (\Seen \Draft) {350}
S: + Ready for literal data S: + Ready for literal data
C: Date: Thu, 1 Jan 2015 00:06:00 -0500 (EST) C: Date: Thu, 1 Jan 2015 00:06:00 -0500 (EST)
C: From: Fritz Schmidt <fritz.ze@example.org> C: From: Fritz Schmidt <fritz.ze@example.org>
C: Subject: happy new year !! C: Subject: happy new year !!
C: To: miss.mitzy@example.org C: To: miss.mitzy@example.org
C: Message-Id: <B238822389-0100000@example.org> C: Message-Id: <B238822389-0100000@example.org>
skipping to change at page 5, line 38 skipping to change at page 5, line 19
optional message date/time string, and a message literal. The optional message date/time string, and a message literal. The
message literal will be appended to the named mailbox, and the message literal will be appended to the named mailbox, and the
message specified by the message identifier will be removed from the message specified by the message identifier will be removed from the
selected mailbox. These operations will appear to the client as a selected mailbox. These operations will appear to the client as a
single action. This has the same effect as the following sequence: single action. This has the same effect as the following sequence:
1. APPEND 1. APPEND
2. [UID] STORE +FLAGS.SILENT \DELETED 2. [UID] STORE +FLAGS.SILENT \DELETED
3. UID EXPUNGE 3. UID EXPUNGE
In the cited sequence, the quota implications of the APPEND are In the cited sequence, the quota implications of APPEND are evaluated
evaluated within the context of the pending EXPUNGE so that only the within the context of the pending EXPUNGE so that only the net quota
net quota consumption is considered. Additionally, the EXPUNGE consumption is considered. Additionally, the EXPUNGE portion of the
portion of the sequence only applies to the specified message, not sequence only applies to the specified message, not all messages
all messages flagged as \Deleted. flagged as "\Deleted".
Although the effect of REPLACE is identical to the steps above, the Although the effect of REPLACE is identical to the steps above, the
semantics are not identical; similar to MOVE [RFC6851], the semantics are not identical; similar to MOVE [RFC6851], the
intermediate states do not occur, and the response codes are intermediate states do not occur and the response codes are
different. In particular, the response codes for APPEND and EXPUNGE different. In particular, the response codes for APPEND and EXPUNGE
will be returned while those for the STORE operation MUST NOT be will be returned while those for the STORE operation MUST NOT be
generated. generated.
When an error occurs while processing REPLACE or UID REPLACE, the When an error occurs while processing REPLACE or UID REPLACE, the
server MUST NOT leave the selected mailbox in an inconsistent state; server MUST NOT leave the selected mailbox in an inconsistent state;
any untagged EXPUNGE response MUST NOT be sent until all actions are any untagged EXPUNGE response MUST NOT be sent until all actions are
successfully completed. successfully completed.
While it may be common for the named mailbox argument to match the While it may be common for the named mailbox argument to match the
selected mailbox for the common use case of replacing a draft, the selected mailbox for the common use case of replacing a draft, the
REPLACE extension intentionally does not require the two to be the REPLACE extension intentionally does not require the two to be the
same. As an example, it's possible to use the REPLACE command to same. As an example, it's possible to use the REPLACE command to
replace a message in the \Drafts special-use mailbox (see [RFC6154]) replace a message in the \Drafts special-use mailbox (see Section 2
with a message in the \Sent special-use mailbox following message of [RFC6154]) with a message in the \Sent special-use mailbox
submission. following message submission.
Because of the similarity of REPLACE to APPEND, extensions that Because of the similarity of REPLACE to APPEND, extensions that
affect APPEND affect REPLACE in the same way. Response codes such as affect APPEND affect REPLACE in the same way. Response codes such as
TRYCREATE (see [RFC3501] Section 6.3.11), along with those defined by TRYCREATE (see Section 6.3.11 of [RFC3501]), along with those defined
extensions, are sent as appropriate. See Section 4 for more by extensions, are sent as appropriate. See Section 4 for more
information about how REPLACE interacts with other IMAP extensions. information about how REPLACE interacts with other IMAP extensions.
3.5. IMAP State Diagram Impacts 3.5. IMAP State Diagram Impacts
Unlike the APPEND command, which is valid in the authenticated state, Unlike the APPEND command, which is valid in the authenticated state,
the REPLACE and UID REPLACE commands MUST only be valid in the the REPLACE and UID REPLACE commands MUST only be valid in the
selected state. This difference from APPEND is necessary since selected state. This difference from APPEND is necessary since
REPLACE operates on message sequence numbers. Additionally, the REPLACE operates on message sequence numbers. Additionally, the
REPLACE extension intentionally follows the convention for UID REPLACE extension intentionally follows the convention for UID
commands found in [RFC3501] section 6.4.8 in that the UID variant of commands found in Section 6.4.8 of [RFC3501] in that the UID variant
the command does not support use from the authenticated state. of the command does not support use from the authenticated state.
4. Interaction with other extensions 4. Interaction with Other Extensions
This section describes how REPLACE interacts with some other IMAP This section describes how REPLACE interacts with some other IMAP
extensions. extensions.
4.1. RFC 4314, ACL 4.1. ACL
The ACL rights [RFC4314] required for UID REPLACE are the union of The Access Control List (ACL) rights [RFC4314] required for UID
the ACL rights required for UID STORE and UID EXPUNGE in the current REPLACE are the union of the ACL rights required for UID STORE and
mailbox, and APPEND in the target mailbox. UID EXPUNGE in the current mailbox, and APPEND in the target mailbox.
4.2. RFC 4469, CATENATE 4.2. CATENATE
Servers supporting both REPLACE and CATENATE [RFC4469] MUST support Servers supporting both REPLACE and CATENATE [RFC4469] MUST support
the addtional append-data and resp-text-code elements defined the the additional append-data and resp-text-code elements defined in
Formal Syntax section of RFC4469 in conjunction with the REPLACE Section 5 ("Formal Syntax") of [RFC4469] in conjunction with the
command. When combined with CATENATE, REPLACE can become a quite REPLACE command. When combined with CATENATE, REPLACE can become
efficient way for message manipulation. quite an efficient way of message manipulation.
Example: Example:
User composes message and attaches photo User composes message and attaches photo
---------------------------------------- ----------------------------------------
C: A010 APPEND Drafts (\Seen \Draft) {1201534} C: A010 APPEND Drafts (\Seen \Draft) {1201534}
S: + Ready for literal data S: + Ready for literal data
C: Date: Thu, 1 Jan 2015 00:10:00 -0500 (EST) C: Date: Thu, 1 Jan 2015 00:10:00 -0500 (EST)
C: From: Fritz Schmidt <fritz.ze@example.org> C: From: Fritz Schmidt <fritz.ze@example.org>
C: Message-ID: <B238822388-0100003@example.org> C: Message-ID: <B238822388-0100003@example.org>
skipping to change at page 8, line 5 skipping to change at page 8, line 5
C: A011 UID REPLACE 3002 Drafts CATENATE (TEXT {71} C: A011 UID REPLACE 3002 Drafts CATENATE (TEXT {71}
S: + Ready for literal data S: + Ready for literal data
C: To: Mitzy <miss.mitzy@example.org> C: To: Mitzy <miss.mitzy@example.org>
C: Subject: My view of the fireworks C: Subject: My view of the fireworks
C: URL "/Drafts/;UID=3002") C: URL "/Drafts/;UID=3002")
S: * OK [APPENDUID 1 3003] Replacement Message ready S: * OK [APPENDUID 1 3003] Replacement Message ready
S: * 5 EXISTS S: * 5 EXISTS
S: * 4 EXPUNGE S: * 4 EXPUNGE
S: A011 OK REPLACE completed S: A011 OK REPLACE completed
4.3. RFC 4315, UIDPLUS 4.3. UIDPLUS
Servers supporting both REPLACE and UIDPLUS [RFC4315] SHOULD send Servers supporting both REPLACE and UIDPLUS [RFC4315] SHOULD send
APPENDUID in response to a UID REPLACE command. For additional APPENDUID in response to a UID REPLACE command. For additional
information see section 3 of RFC4315. Servers implementing REPLACE information, see Section 3 of [RFC4315]. Servers implementing
and UIDPLUS are also advised to send the APPENDUID response code in REPLACE and UIDPLUS are also advised to send the APPENDUID response
an untagged OK before sending the EXPUNGE or replaced responses. code in an untagged OK before sending the EXPUNGE or replaced
(Sending the APPENDUID in the tagged OK as described in the UIDPLUS responses. (Sending APPENDUID in the tagged OK as described in the
specification means that the client first receives an EXPUNGE for a UIDPLUS specification means that the client first receives EXPUNGE
message and afterwards APPENDUID for the new message. It can be for a message and afterwards APPENDUID for the new message. It can
unnecessarily difficult to process that sequence usefully.) be unnecessarily difficult to process that sequence usefully.)
4.4. RFC 6785, IMAP Events in Sieve 4.4. IMAP Events in Sieve
REPLACE applies to IMAP events in Sieve [RFC6785] in the same way REPLACE applies to IMAP events in Sieve [RFC6785] in the same way
that APPEND does. Therefore, REPLACE can cause a Sieve script to be that APPEND does. Therefore, REPLACE can cause a Sieve script to be
invoked with the imap.cause set to "APPEND". Because the invoked with the imap.cause set to "APPEND". Because the
intermediate state of STORE +FLAGS.SILENT \DELETED is not exposed by intermediate state of STORE +FLAGS.SILENT \DELETED is not exposed by
REPLACE, no action will be taken that results in a imap.cause of REPLACE, no action will be taken that results in an imap.cause of
FLAG. FLAG.
4.5. RFC 7162, CONDSTORE/QRESYNC 4.5. CONDSTORE/QRESYNC
Servers implementing both REPLACE and CONDSTORE/QRESYNC [RFC7162] Servers implementing both REPLACE and CONDSTORE/QRESYNC [RFC7162]
MUST treat the message being replaced as if it were being removed MUST treat the message being replaced as if it were being removed
with a UID EXPUNGE command. Sections 3.2.9 and 3.2.10 of RFC 7162 with a UID EXPUNGE command. Sections 3.2.9 and 3.2.10 of [RFC7162]
are particularly relevant for this condition. are particularly relevant for this condition.
4.6. RFC 8474, OBJECTID 4.6. OBJECTID
Servers implementing both REPLACE and OBJECTID [RFC8474] MUST return Servers implementing both REPLACE and OBJECTID [RFC8474] MUST return
different EMAILIDs for both the replaced and replacing messages. The different EMAILIDs for both the replaced and replacing messages. The
only exception to this is the case outlined in OBJECTID section 5.1 only exception to this is the case outlined in Section 5.1 ("EMAILID
when the server detects that both messages' immutable content are Identifier for Identical Messages") of [RFC8474] when the server
identical. detects that both messages' immutable content is identical.
4.7. RFC 3502, MULTIAPPEND 4.7. MULTIAPPEND
The REPLACE extension has no interaction with MULTIAPPEND [RFC3502]. The REPLACE extension has no interaction with MULTIAPPEND [RFC3502].
This document explicitly does not outline a method for replacing This document explicitly does not outline a method for replacing
multiple messsages concurrently. multiple messages concurrently.
5. Formal Syntax 5. Formal Syntax
The following syntax specification uses the Augmented Backus-Naur The following syntax specification uses the Augmented Backus-Naur
Form (ABNF) notation as specified in [RFC5234]. [RFC3501] defines Form (ABNF) notation as specified in [RFC5234]. [RFC3501] defines
the non-terminals "capability","command-select", "mailbox", and "seq- the non-terminals "capability","command-select", "mailbox",
number". [RFC4466] defines the non-terminal "append-message". "seq-number", and "uid". [RFC4466] defines the non-terminal
"append-message".
Except as noted otherwise, all alphabetic characters are case- Except as noted otherwise, all alphabetic characters are case
insensitive. The use of upper or lower case characters to define insensitive. The use of uppercase or lowercase characters to define
token strings is for editorial clarity only. Implementations MUST token strings is for editorial clarity only. Implementations MUST
accept these strings in a case-insensitive fashion. accept these strings in a case-insensitive fashion.
capability =/ "REPLACE" capability =/ "REPLACE"
command-select =/ replace command-select =/ replace
replace = "REPLACE" SP seq-number SP mailbox append-message replace = "REPLACE" SP seq-number SP mailbox append-message
uid =/ replace uid =/ "UID" SP replace
6. Security Considerations 6. Security Considerations
This document is believed to add no security problems beyond those This document is believed to add no security problems beyond those
that may already exist with the base IMAP specification. The REPLACE that may already exist with the base IMAP specification. The REPLACE
command may actually prevent some potential security problems because command may actually prevent some potential security problems because
it avoids intermediate message states that could possibly be it avoids intermediate message states that could possibly be
exploited by an attacker. exploited by an attacker.
7. IANA Considerations 7. IANA Considerations
The IANA is requested to add REPLACE to the "IMAP 4 Capabilities" The IANA has added REPLACE to the "IMAP Capabilities" registry at
registry, http://www.iana.org/assignments/imap4-capabilities. <https://www.iana.org/assignments/imap-capabilities>.
8. Acknowledgements
The author would like to thank the participants of IMAPEXT with
particular thanks to Arnt Gulbrandsen, Alexey Melkinov, Chris Newman,
and Bron Gondwana for their specific contributions.
9. References 8. References
9.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003, 4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003,
<https://www.rfc-editor.org/info/rfc3501>. <https://www.rfc-editor.org/info/rfc3501>.
skipping to change at page 10, line 40 skipping to change at page 10, line 40
<https://www.rfc-editor.org/info/rfc7162>. <https://www.rfc-editor.org/info/rfc7162>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8474] Gondwana, B., Ed., "IMAP Extension for Object [RFC8474] Gondwana, B., Ed., "IMAP Extension for Object
Identifiers", RFC 8474, DOI 10.17487/RFC8474, September Identifiers", RFC 8474, DOI 10.17487/RFC8474, September
2018, <https://www.rfc-editor.org/info/rfc8474>. 2018, <https://www.rfc-editor.org/info/rfc8474>.
9.2. Informative References 8.2. Informative References
[RFC3502] Crispin, M., "Internet Message Access Protocol (IMAP) - [RFC3502] Crispin, M., "Internet Message Access Protocol (IMAP) -
MULTIAPPEND Extension", RFC 3502, DOI 10.17487/RFC3502, MULTIAPPEND Extension", RFC 3502, DOI 10.17487/RFC3502,
March 2003, <https://www.rfc-editor.org/info/rfc3502>. March 2003, <https://www.rfc-editor.org/info/rfc3502>.
[RFC6154] Leiba, B. and J. Nicolson, "IMAP LIST Extension for [RFC6154] Leiba, B. and J. Nicolson, "IMAP LIST Extension for
Special-Use Mailboxes", RFC 6154, DOI 10.17487/RFC6154, Special-Use Mailboxes", RFC 6154, DOI 10.17487/RFC6154,
March 2011, <https://www.rfc-editor.org/info/rfc6154>. March 2011, <https://www.rfc-editor.org/info/rfc6154>.
[RFC6851] Gulbrandsen, A. and N. Freed, Ed., "Internet Message [RFC6851] Gulbrandsen, A. and N. Freed, Ed., "Internet Message
Access Protocol (IMAP) - MOVE Extension", RFC 6851, Access Protocol (IMAP) - MOVE Extension", RFC 6851,
DOI 10.17487/RFC6851, January 2013, DOI 10.17487/RFC6851, January 2013,
<https://www.rfc-editor.org/info/rfc6851>. <https://www.rfc-editor.org/info/rfc6851>.
9.3. URIs Acknowledgements
[1] https://tools.ietf.org/html/bcp14 The author would like to thank the participants of IMAPEXT with
particular thanks to Arnt Gulbrandsen, Alexey Melnikov, Chris Newman,
and Bron Gondwana for their specific contributions.
Author's Address Author's Address
Stuart Brandt Stuart Brandt
Verizon Verizon
22001 Loudoun County Parkway 22001 Loudoun County Parkway
Ashburn, VA 20147 Ashburn, VA 20147
USA United States of America
Email: stujenerin@aol.com Email: stujenerin@aol.com
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