EXTRA K. Murchison
Internet-Draft B. Gondwana
Updates: 5230, 5435 (if approved) FastMail
Intended status: Standards Track November 29, 2018
Expires: June 2, 2019
Sieve Extension: File Carbon Copy (Fcc)
draft-ietf-extra-sieve-fcc-07
Abstract
The Sieve Email Filtering Language provides a number of action
commands, some of which can generate additional messages on behalf of
the user. This document defines an extension to such commands to
allow a copy of any generated message to be filed into a target
mailbox.
This document updates RFC5230 and RFC5435 by adding a new tagged
argument to the "vacation" and "enotify" actions respectively.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
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
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."
This Internet-Draft will expire on June 2, 2019.
Copyright Notice
Copyright (c) 2018 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
Murchison & Gondwana Expires June 2, 2019 [Page 1]
Internet-Draft Sieve Fcc November 2018
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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. Tagged Argument ":fcc" . . . . . . . . . . . . . . . . . . . 3
3.1. Interaction with Fileinto Extensions . . . . . . . . . . 3
3.1.1. Imap4flags Extension . . . . . . . . . . . . . . . . 4
3.1.2. Mailbox Extension . . . . . . . . . . . . . . . . . . 4
3.1.3. Special-Use Extension . . . . . . . . . . . . . . . . 4
3.2. Collected Grammar . . . . . . . . . . . . . . . . . . . . 5
4. Format of File Carbon Copied Messages . . . . . . . . . . . . 5
5. Interaction with the Vacation Action . . . . . . . . . . . . 6
6. Interaction with the Notify Action . . . . . . . . . . . . . 6
6.1. Notification-Capability "fcc" . . . . . . . . . . . . . . 7
7. Compatibility with Other Actions . . . . . . . . . . . . . . 8
8. Implementation Status . . . . . . . . . . . . . . . . . . . . 8
9. Security Considerations . . . . . . . . . . . . . . . . . . . 9
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
10.1. Registration of Sieve Extension . . . . . . . . . . . . 9
10.2. Registration of Notification-Capability
Parameter . . . . . . . . . . . . . . . . . . . . . . . 10
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
12.1. Normative References . . . . . . . . . . . . . . . . . . 10
12.2. Informative References . . . . . . . . . . . . . . . . . 12
12.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Appendix A. Change History (To be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
The Sieve Email Filtering Language [RFC5228] provides a number of
action commands, some of which can generate additional messages on
behalf of the user. It is sometimes desirable for a Sieve user to
maintain an archive of the messages generated by these commands.
This extension defines a new optional tagged argument ":fcc" to
action commands which generate additional messages to allow a copy of
the generated message to be filed into a target mailbox.
The capability string associated with this extension is "fcc".
Murchison & Gondwana Expires June 2, 2019 [Page 2]
Internet-Draft Sieve Fcc November 2018
Each action that generates additional messages will need to specify
how it interfacts with :fcc. This document specifies the interaction
of :fcc with the Vacation [RFC5230] and Notify [RFC5435] extensions.
2. Conventions Used in This Document
Conventions for notations are as in Section 1.1 of [RFC5228],
including use of the "Usage:" label for the definition of action and
tagged arguments syntax.
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.
3. Tagged Argument ":fcc"
This document specifies a new optional tagged argument ":fcc" that
alters the behavior of action commands which generate additional
messages on behalf of the user.
Usage: :fcc <mailbox: string>
The :fcc tagged argument instructs the Sieve interpreter to file a
copy of the generated message into the mailbox provided in the
subsequent argument. The syntax and semantics of the mailbox
argument MUST match those of the mailbox argument to the "fileinto"
action specified in Section 4.1 of [RFC5228]. If the specified
mailbox doesn't exist, the implementation MUST file the message into
the user's main mailbox (e.g. IMAP "INBOX").
3.1. Interaction with Fileinto Extensions
Some tagged arguments defined in extensions to the "fileinto" action
can be used together with ":fcc". The sections below describe these
interactions. Tagged arguments in future extensions to the
"fileinto" action should describe their interaction with ":fcc", if
any.
When any "fileinto" extension arguments are used with ":fcc", the
corresponding extension MUST be enabled, and the arguments MUST have
the same syntax and semantics as they do with "fileinto".
Murchison & Gondwana Expires June 2, 2019 [Page 3]
Internet-Draft Sieve Fcc November 2018
3.1.1. Imap4flags Extension
This document extends the definition of the ":flags" tagged argument
(see Section 5 of [RFC5232]) so that it can optionally be used with
the ":fcc" argument.
Usage: :fcc <mailbox: string> [:flags <list-of-flags: string-list>]
If the optional ":flags" argument is specified with ":fcc", it
instructs the Sieve interpreter to set the IMAP4 flags provided in
the subsequent argument when the generated message is filed into the
target mailbox.
3.1.2. Mailbox Extension
This document extends the definition of the ":create" tagged argument
(see Section 3.2 of [RFC5490]) so that it can optionally be used with
the ":fcc" argument.
Usage: :fcc <mailbox: string> [:create]
If the optional ":create" argument is specified with ":fcc", it
instructs the Sieve interpreter to create the target mailbox, if
needed, before attempting to file the generated message into the
target mailbox.
3.1.3. Special-Use Extension
This document extends the definition of the ":specialuse" tagged
argument (see Section 4 of [I-D.ietf-extra-sieve-special-use]) so
that it can optionally be used with the ":fcc" argument.
Usage: :fcc <mailbox: string> [:specialuse <special-use-flag: string>]
If the optional ":specialuse" argument is specified with ":fcc", it
instructs the Sieve interpreter to check whether a mailbox exists
with the specific special-use flag assigned to it. If such a mailbox
exists, the generated message is filed into the special-use mailbox.
Otherwise, the generated message is filed into the target mailbox.
If both the optional ":specialuse" and ":create" arguments are
specified with ":fcc", the Sieve interpreter is instructed to create
the target mailbox per Section 4.1 of
[I-D.ietf-extra-sieve-special-use], if needed.
Murchison & Gondwana Expires June 2, 2019 [Page 4]
Internet-Draft Sieve Fcc November 2018
3.2. Collected Grammar
For convenience, the "FCC" syntax element is defined here using ABNF
[RFC5234] so that it can be augmented by other extensions.
FCC = ":fcc" string *FCC-OPTS
FCC-OPTS = CREATE / IMAP-FLAGS / SPECIAL-USE
; each option MUST NOT appear more than once
CREATE = ":create"
IMAP-FLAGS = ":flags" string-list
SPECIAL-USE = ":specialuse" string
4. Format of File Carbon Copied Messages
Copies of messages filed into a mailbox via this extension are
REQUIRED to be in Internet Message Format [RFC5322]. Some messages
generated by Sieve actions might already conform to this format and
MAY be filed without modification. Messages generated in other
formats MUST be encapsulated using constructs from [RFC5322] and MIME
([RFC2045], [RFC2046], [RFC2047], [RFC2231]).
The general requirements for encapsulating the copies of messages to
be filed are the following:
o Date: The Date header field is REQUIRED and SHOULD be set to the
date and time when the message was generated.
o From: The From header field is REQUIRED and SHOULD be set to the
email address of the owner of the Sieve script, unless explicitly
overridden by rules for encapsulating a particular message type.
o To: The To header field is OPTIONAL and MAY be set to the email
address of the recipient of the generated message, if available.
o Subject: The Subject header field is OPTIONAL and MAY be generated
as follows: The subject is set to the characters "Fcc: " followed
by the subject of the message being processed by the Sieve
interpreter.
o In-Reply-To: The In-Reply-To header field is OPTIONAL and MAY be
set to the Message-ID of the message being processed by the Sieve
interpreter.
o Message Body: The body of the filed message is REQUIRED and is
composed of one or more MIME-parts containing the generated
message and any related metadata. The Content-Type header
Murchison & Gondwana Expires June 2, 2019 [Page 5]
Internet-Draft Sieve Fcc November 2018
field(s) MUST be set to the appropriate MIME types. If any of the
MIME-parts include 8-bit or binary data, the Content-Transfer-
Encoding header field(s) MUST be set accordingly.
5. Interaction with the Vacation Action
This document extends the "vacation" [RFC5230] action (see also
"vacation-seconds" [RFC6131]) to optionally store a copy of the auto-
reply messages into a target mailbox.
Usage: vacation [FCC]
[":days" number | ":seconds" number]
[":subject" string]
[":from" string]
[":addresses" string-list]
[":mime"]
[":handle" string]
<reason: string>
Example (with fileinto extensions):
require ["vacation", "fcc", "mailbox", "special-use", "imap4flags"];
vacation :days 7
:from "hemingway@example.com" "Gone Fishin'"
:fcc "INBOX.Sent" :flags ["\\Seen"]
:specialuse "\\Sent" :create;
Vacation auto-reply messages are MIME-compliant and can be filed into
the target mailbox without modification.
6. Interaction with the Notify Action
This document extends the "notify" [RFC5435] action to optionally
store a copy of the notification messages into a target mailbox.
Usage: notify [FCC]
[":from" string]
[":importance" <"1" / "2" / "3">]
[":options" string-list]
[":message" string]
<method: string>
Murchison & Gondwana Expires June 2, 2019 [Page 6]
Internet-Draft Sieve Fcc November 2018
Example:
require ["enotify", "fcc"];
notify :fcc "INBOX.Sent"
:message "You got mail!"
"mailto:ken@example.com";
Messages generated using the "mailto" [RFC5436] notification method
are MIME-compliant and can be filed into the target mailbox without
modification.
Messages generated by other notification methods (e.g. "xmpp"
[RFC5437]) MUST be encapsulated per Section 4 before being filed.
The body of the filed message MUST include the :message parameter and
MAY include one or more of the :from, :importance, or :options
parameters. The MIME-type(s) of the body part(s) used to encapsulate
the parameters is an implementation decision.
An implementation MAY only support :fcc in conjunction with a subset
of the notification methods it supports. An error occurs if :fcc is
combined with a notification method that doesn't support it.
Notification methods that support :fcc can be discovered at run-time
using the mechanism described below (Section 6.1).
6.1. Notification-Capability "fcc"
This document defines a new notification-capability value "fcc" for
use with the notify_method_capability test (see Section 5 of
[RFC5435]. For the "fcc" notification-capability, the
notify_method_capability test can match one of the following key-list
values:
yes A copy of the notification message sent using the method
identified by the notification-uri can be filed into a target
mailbox.
no A copy of the notification message sent using the method
identified by the notification-uri can not be filed into a target
mailbox.
Note that the "fcc" notify_method_capability test does not require
the notification-uri argument to specify anything other than a
scheme.
Murchison & Gondwana Expires June 2, 2019 [Page 7]
Internet-Draft Sieve Fcc November 2018
Example:
require ["enotify", "fcc"];
if notify_method_capability "xmpp:" "fcc" "yes" {
notify :fcc "INBOX.Sent"
:message "You got mail"
"xmpp:ken@example.com?message;subject=SIEVE";
} else {
notify :fcc "INBOX.Sent"
:message "You got mail!"
"mailto:ken@example.com";
}
7. Compatibility with Other Actions
The "fcc" extension is not compatible with any Sieve action that does
not generate an additional message on behalf of the user. It is an
error for a script to use the ":fcc" tagged argument with any such
action.
Future extensions that define actions that generate additional
messages on behalf of the user should describe their compatibility
with ":fcc", and how to MIME-encapsulate the message, if required.
8. Implementation Status
< RFC Editor: before publication please remove this section and the
reference to [RFC7942] >
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
Murchison & Gondwana Expires June 2, 2019 [Page 8]
Internet-Draft Sieve Fcc November 2018
It is up to the individual working groups to use this information as
they see fit".
8.1. Cyrus Server
The open source Cyrus Server [2] project is a highly scalable
enterprise mail system which supports Sieve email filtering at the
point of final delivery. This production level Sieve implementation
supports all of the requirements described in this document. This
implementation is freely distributable under a BSD style license from
Computing Services at Carnegie Mellon University [3].
8.2. Oracle Communications Messaging Server
The Oracle Communications Messaging Server [4] is a highly scalable,
reliable, and available messaging platform. This production level
product supports the :fcc extension in conjunction with both the
notify and vacation extensions. The implementation meets all the
requirements given in this document. The product also supports the
imap4flags extension so the :flags may be used in conjunction :fcc.
9. Security Considerations
The "fcc" extension does not raise any other security considerations
that are not already present in [RFC5228], [RFC5230], [RFC5435], and
[RFC6131].
10. IANA Considerations
10.1. Registration of Sieve Extension
To: iana@iana.org
Subject: Registration of new Sieve extension
Capability name: fcc
Description: Adds the ":fcc" parameter to Sieve action commands
that generate additional messages.
RFC number: RFC XXXX
Contact address: The Sieve discussion list <sieve@ietf.org>
Murchison & Gondwana Expires June 2, 2019 [Page 9]
Internet-Draft Sieve Fcc November 2018
10.2. Registration of Notification-Capability Parameter
To: iana@iana.org
Subject: Registration of a new notification-capability parameter
Capability name: fcc
Description: Returns whether a copy of the notification message
sent using the method identified by the notification-uri parameter
to the notify_method_capability test can be filed into a target
mailbox.
Syntax: Can contain one of two values: "yes" or "no". Values MUST
be in lowercase.
Permanent and readily available reference(s): This RFC
Contact information: The Sieve discussion list <ietf-mta-
filters@imc.org>
11. Acknowledgments
The authors would like to thank the following individuals for
contributing their ideas and support for writing this specification:
Ned Freed, Stan Kalisch, and Alexey Melnikov.
12. References
12.1. Normative References
[]
Bosch, S., "Sieve Email Filtering: Delivering to Special-
Use Mailboxes", draft-ietf-extra-sieve-special-use-04
(work in progress), November 2018.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, DOI 10.17487/RFC2045, November 1996,
<https://www.rfc-editor.org/info/rfc2045>.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
DOI 10.17487/RFC2046, November 1996,
<https://www.rfc-editor.org/info/rfc2046>.
Murchison & Gondwana Expires June 2, 2019 [Page 10]
Internet-Draft Sieve Fcc November 2018
[RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Three: Message Header Extensions for Non-ASCII Text",
RFC 2047, DOI 10.17487/RFC2047, November 1996,
<https://www.rfc-editor.org/info/rfc2047>.
[RFC2119] 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/info/rfc2119>.
[RFC2231] Freed, N. and K. Moore, "MIME Parameter Value and Encoded
Word Extensions: Character Sets, Languages, and
Continuations", RFC 2231, DOI 10.17487/RFC2231, November
1997, <https://www.rfc-editor.org/info/rfc2231>.
[RFC5228] Guenther, P., Ed. and T. Showalter, Ed., "Sieve: An Email
Filtering Language", RFC 5228, DOI 10.17487/RFC5228,
January 2008, <https://www.rfc-editor.org/info/rfc5228>.
[RFC5230] Showalter, T. and N. Freed, Ed., "Sieve Email Filtering:
Vacation Extension", RFC 5230, DOI 10.17487/RFC5230,
January 2008, <https://www.rfc-editor.org/info/rfc5230>.
[RFC5232] Melnikov, A., "Sieve Email Filtering: Imap4flags
Extension", RFC 5232, DOI 10.17487/RFC5232, January 2008,
<https://www.rfc-editor.org/info/rfc5232>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<https://www.rfc-editor.org/info/rfc5322>.
[RFC5435] Melnikov, A., Ed., Leiba, B., Ed., Segmuller, W., and T.
Martin, "Sieve Email Filtering: Extension for
Notifications", RFC 5435, DOI 10.17487/RFC5435, January
2009, <https://www.rfc-editor.org/info/rfc5435>.
[RFC5490] Melnikov, A., "The Sieve Mail-Filtering Language --
Extensions for Checking Mailbox Status and Accessing
Mailbox Metadata", RFC 5490, DOI 10.17487/RFC5490, March
2009, <https://www.rfc-editor.org/info/rfc5490>.
Murchison & Gondwana Expires June 2, 2019 [Page 11]
Internet-Draft Sieve Fcc November 2018
[RFC8174] 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>.
12.2. Informative References
[RFC5436] Leiba, B. and M. Haardt, "Sieve Notification Mechanism:
mailto", RFC 5436, DOI 10.17487/RFC5436, January 2009,
<https://www.rfc-editor.org/info/rfc5436>.
[RFC5437] Saint-Andre, P. and A. Melnikov, "Sieve Notification
Mechanism: Extensible Messaging and Presence Protocol
(XMPP)", RFC 5437, DOI 10.17487/RFC5437, January 2009,
<https://www.rfc-editor.org/info/rfc5437>.
[RFC6131] George, R. and B. Leiba, "Sieve Vacation Extension:
"Seconds" Parameter", RFC 6131, DOI 10.17487/RFC6131, July
2011, <https://www.rfc-editor.org/info/rfc6131>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
12.3. URIs
[1] https://tools.ietf.org/html/bcp14
[2] http://www.cyrusimap.org/
[3] http://www.cmu.edu/computing/
[4] https://www.oracle.com/industries/communications/enterprise/
products/messaging-server/index.html
Appendix A. Change History (To be removed by RFC Editor before
publication)
Changes since draft-ietf-extra-sieve-fcc-06:
o Reorganized sections.
o Switched to using proper ABNF for FCC and fileinto extensions.
o Fcc into INBOX if specified target mailbox doesn't exist.
o Editorial changes from Alexey Melnikov.
Murchison & Gondwana Expires June 2, 2019 [Page 12]
Internet-Draft Sieve Fcc November 2018
o Other minor editorial changes.
Changes since draft-ietf-extra-sieve-fcc-05:
o Editorial changes from Jiankang Yao.
Changes since draft-ietf-extra-sieve-fcc-04:
o Editorial changes from Ned Freed.
o Added information on Oracle implementation.
Changes since draft-ietf-extra-sieve-fcc-03:
o Fixed typo in ABNF.
Changes since draft-ietf-extra-sieve-fcc-02:
o Updated Keywords boilerplate.
o Noted that :fcc mailbox argument and any fileinto extension
arguments used wth :fcc have the same syntax and semantics as they
have with fileinto.
o Removed section on [e]Reject.
o Added "fcc" notification-capability.
o Added Implementation Status section.
o Editorial changes from Ned Freed.
Changes since draft-ietf-extra-sieve-fcc-01:
o Added text discussing how to handle generated messages that are
not in MIME format.
o Adjusted ABNF so that tagged arguments that supplement :fcc no
longer appear as positional.
Changes since draft-ietf-extra-sieve-fcc-00:
o Updated abstract with text from Ned.
o Added support for :fcc to notify extension.
o Prohibit use of :fcc with reject and ereject extensions.
Murchison & Gondwana Expires June 2, 2019 [Page 13]
Internet-Draft Sieve Fcc November 2018
o Added registration of the extension with IANA.
o Added Acknowledgments.
o Minor editorial changes.
Authors' Addresses
Kenneth Murchison
FastMail US LLC
1429 Walnut Street - Suite 1201
Philadelphia, PA 19102
USA
Email: murch@fastmailteam.com
Bron Gondwana
FastMail Pty Ltd
Level 2, 114 William Street
Melbourne, VIC 3000
Australia
Email: brong@fastmailteam.com
Murchison & Gondwana Expires June 2, 2019 [Page 14]