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Tuesday, October 30, 2007

Sieve Email Filtering: Representing Sieves and Display Directives in XML

This document describes a way to represent Sieve email filtering language
scripts in XML. Sieve ("Sieve: An Email Filtering Language") is a
language for filtering email messages at or around the time of final
delivery. It is designed to be implementable on either a mail client or
mail server. It is meant to be extensible, simple, and independent of
access protocol, mail architecture, and operating system and it is
intended to be manipulated by a variety of different user interfaces.
Some user interface environments have extensive existing facilities for
manipulating material represented in XML. While adding support for
alternate data syntaxes may be possible in most if not all of these
environments, it may not be particularly convenient to do so. The obvious
way to deal with this issue is to map sieves into XML, possibly on a
separate backend system, manipulate the XML, and convert it back to
normal Sieve format. Several Sieve extensions have already been specified
(RFC 3431, RFC 3598, RFC 3685, RFC 3934) and many more are planned. The
set of extensions available varies from one implementation to the next
and may even change as a result of configuration choices. It is therefore
essential that the XML representation of Sieve be able to accommodate
Sieve extensions without requiring schema changes. It is also desirable
that Sieve extensions not require changes to the code that converts to
and from the XML representation. This specification defines an XML
representation for sieve scripts and explains how the conversion process
to and from XML works. The XML representation is capable of accommodating
any future Sieve extension as long as the underlying Sieve grammar
remains unchanged. Furthermore, code that converts from XML to the
normal Sieve format requires no changes to accommodate extensions,
while code used to convert from normal Sieve format to XML only requires
changes when new control commands are added -- a rare event. An XML
Schema and sample code to convert to and from XML format are also
provided in the appendices. More Information
See also the IETF Sieve Mail Filtering Language (SIEVE) Working Group Charter: Click Here

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