Network Working Group                                        A. Melnikov
Internet-Draft                                             Isode Limited
Intended status: Standards Track                                  Q. Sun
Expires: January 6, 2009                             Huawei Technologies
                                                            July 5, 2008


        Sieve Extension for converting messages before delivery
                    draft-melnikov-sieve-convert-00

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Abstract

   This document describes how Lemonade CONVERT can be used to transform
   messages before final delivery.












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Table of Contents

   1.  Conventions Used in this Document . . . . . . . . . . . . . . . 3

   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3

   3.  :converted tagged argument to the 'fileinto' action . . . . . . 3

   4.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4

   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4

   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 4

   8.  Normative References  . . . . . . . . . . . . . . . . . . . . . 4

       Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . 5
       Intellectual Property and Copyright Statements  . . . . . . . . 6































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1.  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 RFC 2119 [RFC2119].

   Conventions for notations are as in [SIEVE] section 1.1, including
   the use of [ABNF].


2.  Introduction

   The [CONVERT] extension adds an IMAP command for performing client
   controlled conversions on whole messages or their body parts.  This
   document defines a similar extension to the SIEVE [SIEVE] mail
   filtering language, which reuses conversion parameters and framework
   established by [CONVERT].


3.  :converted tagged argument to the 'fileinto' action

   Usage:  :converted <quoted-from-mime-type: string>
           <quoted-to-mime-type: string>
           <transcoding-params: string-list>

   The :converted tag specifies that all body parts with "quoted-from-
   mime-type" MIME type should be converted to "quoted-to-mime-type"
   MIME type using conversion parameters specified in "transcoding-
   params".  Each conversion parameter value has the following syntax:
   "<transcoding-param>=<transcoding-param-value>", where <transcoding-
   param> and <transcoding-param-value> are defined in [CONVERT].
   Messages which don't have any body part with the "quoted-from-mime-
   type" MIME type are not affected by the conversion.

   [[anchor3: Should there be a way to specify/restrict which specific
   body parts need to be converted (e.g. only the second body part)?
   Should there be a way to specify multiple conversions (on differt
   body parts of the same message)?]]

   [[anchor4: Interaction with MIME Loops (e.g. if :converted is
   applicable to the replace action) should be specified.]]


4.  Examples

   In the following examples all "image/tiff" body parts of the message
   are converted to "image/jpeg" with image resolution of 320x480
   pixels.



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       require ["fileinto", "convert"];

       fileinto :convert "image/tiff" "image/jpeg" "pix-x" "320"
                "pix-y" "480" "INBOX";

   Messages which don't have image/tiff body parts are delivered to
   INBOX as is.


5.  Security Considerations

   [[anchor6: TBD]]


6.  IANA Considerations

   IANA is requested to add the following registrations to the list of
   Sieve extensions:

   Capability name:  convert
   Description:  adds a new tag to the fileinto action that enables
      Sieve script to perform a conversion on the message being
      delivered.
   RFC number:  this RFC
   Contact address:  The Sieve discussion list
      <ietf-mta-filters@imc.org>


7.  Acknowledgements

   [[anchor9: TBD]].


8.  Normative References

   [ABNF]     Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 4234, October 2005.

   [CONVERT]  Melnikov, A., Ed. and P. Coates, Ed., "IMAP CONVERT
              extension", draft-ietf-lemonade-convert-20 (work in
              progress), May 2008.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", RFC 2119, BCP 14, March 1997.

   [SIEVE]    Guenther, P., Ed. and T. Showalter, Ed., "Sieve: An Email
              Filtering Language", RFC 5228, January 2008.




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Authors' Addresses

   Alexey Melnikov
   Isode Limited
   5 Castle Business Village
   36 Station Road
   Hampton, Middlesex  TW12 2BX
   UK

   Email: Alexey.Melnikov@isode.com
   URI:   http://www.melnikov.ca/


   Qian Sun
   Huawei Technologies
   Bantian Longgang
   Shenzhen, Guandong  518129
   P.R China

   Phone: +86 755 28780808
   Email: sunqian@huawei.com






























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