doc: Add RFC documents

1 files changed, 395 insertions, 0 deletions

diff --git a/doc/rfc/rfc8514.txt b/doc/rfc/rfc8514.txt
new file mode 100644
index 0000000..9a8ea9b
--- /dev/null
+++ b/doc/rfc/rfc8514.txt
@@ -0,0 +1,395 @@
+
+
+
+
+
+
+Internet Engineering Task Force (IETF)                          S. Bosch
+Request for Comments: 8514                               Open Xchange Oy
+Category: Standards Track                                   January 2019
+ISSN: 2070-1721
+
+
+      Internet Message Access Protocol (IMAP) - SAVEDATE Extension
+
+Abstract
+
+   This document adds a new capability called "SAVEDATE" to the Internet
+   Message Access Protocol (IMAP).  It defines a new IMAP message
+   attribute called "save date" that, unlike the existing "internal
+   date" attribute, always indicates the moment at which the message was
+   saved in its current mailbox.  The SAVEDATE capability extends the
+   FETCH command with the means to retrieve the save date attribute and
+   extends the SEARCH command to allow using the save date attribute in
+   searching criteria.
+
+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 7841.
+
+   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/rfc8514.
+
+Copyright Notice
+
+   Copyright (c) 2019 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
+   (https://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.
+
+
+
+
+Bosch                        Standards Track                    [Page 1]
+
+RFC 8514                IMAP - SAVEDATE Extension           January 2019
+
+
+Table of Contents
+
+   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
+   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
+   3.  Save Date Message Attribute . . . . . . . . . . . . . . . . .   3
+   4.  IMAP Protocol Changes . . . . . . . . . . . . . . . . . . . .   4
+     4.1.  CAPABILITY Identification . . . . . . . . . . . . . . . .   4
+     4.2.  FETCH Command and Response Extensions . . . . . . . . . .   4
+     4.3.  SEARCH Command Extension  . . . . . . . . . . . . . . . .   4
+   5.  Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . .   5
+   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
+   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
+   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
+   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   7
+   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7
+
+1.  Introduction
+
+   This document extends the Internet Message Access Protocol (IMAP)
+   [IMAP4rev1] with a new capability called "SAVEDATE".  This capability
+   adds a new IMAP message attribute called "save date".  The save date
+   is the date and time at which a message was saved in the mailbox in
+   which it currently resides.  The save date is similar to the existing
+   "internal date" attribute in that it is set at the time of delivery.
+   However, the internal date attribute can be set to an arbitrary value
+   for messages delivered to the mailbox using the APPEND command and is
+   usually copied from the source message for messages delivered using
+   the COPY command.  In contrast, the save date attribute is always set
+   to the current date and time at the moment the message is saved in
+   the mailbox, irrespective of how the message is delivered and from
+   where it originates.
+
+   The save date attribute is useful for implementing automated removal
+   of messages from a mailbox after a configured amount of time.  For
+   that application, it is necessary to know when the message was saved
+   in the mailbox, which cannot be reliably determined using the
+   internal date attribute.
+
+   For example, a common client usage pattern is to move deleted
+   messages to a Trash mailbox.  These messages are considered "deleted"
+   at the time they are moved to the Trash mailbox.  In an effort to
+   limit the size of the Trash mailbox, a client may subsequently desire
+   to permanently remove (expunge) all messages in that Trash mailbox
+   deleted before a certain time (e.g., a configurable expiration
+   interval).  In that case, the internal date attribute cannot be used
+   since it likely refers to the time at which the message was
+   originally received.  The proper time comparison attribute should
+
+
+
+
+Bosch                        Standards Track                    [Page 2]
+
+RFC 8514                IMAP - SAVEDATE Extension           January 2019
+
+
+   instead be the time at which the message was saved to the Trash
+   mailbox.  Similar usage patterns can be observed for archiving
+   solutions.
+
+   The SAVEDATE capability extends the FETCH command and response to
+   allow retrieving the date and time at which a message was saved.
+   Also, the SAVEDATE capability extends the SEARCH command to allow
+   searching messages with criteria based on when they were saved in the
+   mailbox.
+
+2.  Conventions Used in This Document
+
+   In examples, "C:" indicates lines sent by a client that is connected
+   to a server.  "S:" indicates lines sent by the server to the client.
+
+   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 [KEYWORDS] [KEYWORDS-UPD] when, and only when, they appear in
+   all capitals, as shown here.
+
+3.  Save Date Message Attribute
+
+   The save date message attribute is the date and time at which the
+   message was saved in the mailbox it is now located in.  Unlike the
+   internal date message attribute defined by [IMAP4rev1], this date and
+   time value cannot be set arbitrarily when a message is delivered by
+   the IMAP APPEND command.  Also, when a message is delivered to the
+   mailbox by the IMAP COPY command [IMAP4rev1] or the IMAP MOVE command
+   [IMAP-MOVE], the save date attribute is not copied from the source
+   message.  Instead, the current date and time at which the message is
+   delivered to a mailbox MUST be used to set the save date attribute.
+   Once calculated, the save date attribute MUST NOT change as long as
+   the message is contained within the same mailbox.
+
+   This means that when the message is copied to another mailbox, the
+   save date of the message in the source mailbox remains unaffected;
+   only the new copy of the message gets a new save date.  Consequently,
+   when the message is moved to another mailbox, either using the MOVE
+   command or a command sequence involving the COPY command [IMAP-MOVE],
+   the message always gets a new save date in the destination mailbox.
+
+   For some specific mailboxes, the underlying storage may not support
+   the save date attribute.  The handling of this situation is described
+   in detail in the next section for each involved IMAP command.
+
+
+
+
+
+
+Bosch                        Standards Track                    [Page 3]
+
+RFC 8514                IMAP - SAVEDATE Extension           January 2019
+
+
+4.  IMAP Protocol Changes
+
+4.1.  CAPABILITY Identification
+
+   IMAP servers that support this extension MUST include "SAVEDATE" in
+   the response list to the CAPABILITY command.
+
+4.2.  FETCH Command and Response Extensions
+
+   This extension defines one new data item for the FETCH command:
+
+   SAVEDATE
+      The save date of the message.
+
+   This extension defines one new data item for the FETCH response:
+
+   SAVEDATE
+      A string representing the save date of the message.  However, if
+      the underlying mailbox storage does not support the save date
+      message attribute, the value returned for the SAVEDATE item is
+      always NIL, rather than a string.
+
+   Example:
+
+         C: A101 FETCH 998 (SAVEDATE)
+         S: * 998 FETCH (SAVEDATE "01-Jan-2015 18:50:53 +0100")
+         S: A101 OK Fetch completed.
+
+4.3.  SEARCH Command Extension
+
+   This extension defines four new search keys for the SEARCH command:
+
+   SAVEDBEFORE <date>
+      Messages whose save date (disregarding time and timezone) is
+      earlier than the specified date.
+
+   SAVEDON <date>
+      Messages whose save date (disregarding time and timezone) is
+      within the specified date.
+
+   SAVEDSINCE <date>
+      Messages whose save date (disregarding time and timezone) is
+      within or later than the specified date.
+
+
+
+
+
+
+
+
+Bosch                        Standards Track                    [Page 4]
+
+RFC 8514                IMAP - SAVEDATE Extension           January 2019
+
+
+   SAVEDATESUPPORTED
+      Matches all messages in the mailbox when the underlying storage of
+      that mailbox supports the save date attribute.  Conversely, it
+      matches no messages in the mailbox when the save date attribute is
+      not supported.
+
+   When the underlying storage of a mailbox does not support the save
+   date attribute, the SAVEDBEFORE, SAVEDON, and SAVEDSINCE search keys
+   MUST use the internal date attribute instead.  In the context of the
+   IMAP Multimailbox SEARCH Extension [MULTISEARCH], this fallback
+   behavior MUST apply to each mailbox individually, meaning that only
+   the mailboxes that lack support for the save date attribute use the
+   internal date attribute instead.
+
+   Example:
+
+         C: A102 SEARCH SAVEDON 28-Dec-2014
+         S: * SEARCH 993 994
+         S: A102 OK Search completed.
+         C: A103 SEARCH SAVEDSINCE 28-Dec-2014
+         S: * SEARCH 993 994 995 996 997 998 999 1000 1001
+         S: A103 OK Search completed.
+
+5.  Formal Syntax
+
+   The following syntax specification augments the grammar specified in
+   [IMAP4rev1].  It uses the Augmented Backus-Naur Form (ABNF) notation
+   as specified in [ABNF].  Elements not defined here are taken from
+   [IMAP4rev1].
+
+   capability     =/ "SAVEDATE"
+
+   fetch-att      =/ "SAVEDATE"
+
+   msg-att-static =/ "SAVEDATE" SP (date-time / nil)
+
+   search-key     =/ "SAVEDBEFORE" SP date /
+                     "SAVEDON" SP date /
+                     "SAVEDSINCE" SP date /
+                     "SAVEDATESUPPORTED"
+
+6.  Security Considerations
+
+   There are no known additional security issues with this extension
+   beyond those described in the base protocol described in [IMAP4rev1].
+
+
+
+
+
+
+Bosch                        Standards Track                    [Page 5]
+
+RFC 8514                IMAP - SAVEDATE Extension           January 2019
+
+
+7.  IANA Considerations
+
+   IANA has added "SAVEDATE" to the "IMAP Capabilities" registry located
+   at <https://www.iana.org/assignments/imap-capabilities>.
+
+8.  Normative References
+
+   [ABNF]     Crocker, D. and P. Overell, "Augmented BNF for Syntax
+              Specifications: ABNF", STD 68, RFC 5234,
+              DOI 10.17487/RFC5234, January 2008,
+              <https://www.rfc-editor.org/rfc/rfc5234>.
+
+   [IMAP-MOVE]
+              Gulbrandsen, A. and N. Freed, "Internet Message Access
+              Protocol (IMAP) - MOVE Extension", RFC 6851,
+              DOI 10.17487/RFC6851, January 2013,
+              <https://www.rfc-editor.org/rfc/rfc6851>.
+
+   [IMAP4rev1]
+              Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
+              4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003,
+              <https://www.rfc-editor.org/rfc/rfc3501>.
+
+   [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
+              Requirement Levels", BCP 14, RFC 2119,
+              DOI 10.17487/RFC2119, March 1997,
+              <https://www.rfc-editor.org/rfc/rfc2119>.
+
+   [KEYWORDS-UPD]
+              Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
+              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
+              May 2017, <https://www.rfc-editor.org/info/rfc8174>.
+
+   [MULTISEARCH]
+              Leiba, B. and A. Melnikov, "IMAP4 Multimailbox SEARCH
+              Extension", RFC 7377, DOI 10.17487/RFC7377, October 2014,
+              <https://www.rfc-editor.org/info/rfc7377>.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Bosch                        Standards Track                    [Page 6]
+
+RFC 8514                IMAP - SAVEDATE Extension           January 2019
+
+
+Acknowledgements
+
+   Thanks to Bron Gondwana, Alexey Melnikov, Timo Sirainen, and Michael
+   Slusarz for reviews and suggestions.
+
+Author's Address
+
+   Stephan Bosch
+   Open Xchange Oy
+   Lars Sonckin kaari 12
+   Espoo  02600
+   Finland
+
+   Email: stephan.bosch@open-xchange.com
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Bosch                        Standards Track                    [Page 7]
+