Extdata extension for Pigeonhole Sieve v0.6

Introduction
------------

Sieve (RFC 5228) is a highly extensible machine language specifically tailored for
internet message filtering. For the Dovecot Secure IMAP server, Sieve support is
provided by the Pigeonhole Sieve plugin. This package extends the Sieve filtering
implementation with an extension to support retrieving string values from external 
sources.  The extension supplies a new test so that external data can be examined. 
When the variables extension (RFC5229) is also active, the external data can also
be accessed from a special variables namespace.

This extension is specific to the Pigeonhole Sieve implementation for the Dovecot
Secure IMAP server.  It will therefore most likely not be supported by web 
interfaces or GUI-based Sieve editors.  This extension is primarily meant for use 
in global scripts that are managed by the systems administrator.

On the background, this plugin uses Dovecot's dict support as a generic interface
for accessing data stores. Through this interface the extdata extension can
provide access a SQL database for example.

Compiling and Configuring
-------------------------

Refer to INSTALL file.

Using
-----

Refer to doc/rfc/spec-bosch-sieve-extdata.txt for a specification of the Sieve
language extension.

Currently, only one external data store may be specified using a dict uri. Data 
items referenced from the Sieve script are simple identifiers that are queried from
the dict lookup, after being prefixed with "priv/". So, the data item "name" 
(or as a variable "${extdata.name}") will map to "priv/name" in the dict.  

Implementation Status
---------------------

The Extdata Sieve language extension is vendor-specific with draft status and the
implementation is experimental, which means that the language extension is still 
subject to change and that the current implementation is not thoroughly tested.

Authors
-------

Refer to AUTHORS file.

Contact Info
------------

Stephan Bosch <stephan at rename-it dot nl>
IRC: Freenode, #dovecot, S[r]us
Web: http://pigeonhole.dovecot.org

Please use the Dovecot mailing list <dovecot at dovecot.org> for questions about 
this package. You can post to the list without subscribing, the mail then waits 
in a moderator queue for a while. See http://dovecot.org/mailinglists.html