dovecot - May 2007 - per-user delivery to commands

Hi, we are using dovecot IMAP in a complex virtual setup with almost
4000 accounts; postfix hands over to deliver for local delivery into
a home directory as stored in the SQL database. That's
/srv/vmail/$DOMAIN/$LOCALPART for most of them, but I'd rather not
hardcode this scheme anywhere as it's in SQL.

By a policy change, we need to insert a filter in this chain and the
filter must be called in such a way that it knows where to find the
"home" directory since the command needs to read a configuration
file in ~/.mailfilt.rc.

Thus I am looking for a way to make deliver pass incoming messages
via this filter, but I cannot find any way to do that. Ideally
I want this to happen before the LDA runs the mail through sieve.

As an alternative, is there a command I can call to make dovecot
look up $HOME for me so that I can use the dovecot data in the SQL
database without making assumptions about the representation?
A command that would proxy and convert my request into an SQL select
as per dovecot.conf and feed back the result? Then I could use
a Maildir delivery programme or even procmail to do the delivery
according to the dovecot configruation.

Thanks for any insights, hints, tips, help, jokes, flames, and
useful information.

-- 
martin;              (greetings from the heart of the sun.)
  \____ echo mailto: !#^."<*>"|tr "<*> mailto:"
net at madduck
 
spamtraps: madduck.bogus at madduck.net
 
will kill for oil!
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also sprach martin f krafft <madduck at madduck.net> [2007.05.20.1843
+0200]:
> Hi, we are using dovecot IMAP in a complex virtual setup with almost
> 4000 accounts; postfix hands over to deliver for local delivery into
> a home directory as stored in the SQL database. That's
> /srv/vmail/$DOMAIN/$LOCALPART for most of them, but I'd rather not
> hardcode this scheme anywhere as it's in SQL.
/srv/vmail/$DOMAIN/$LOCALPART/Maildir/

since ?
> By a policy change, we need to insert a filter in this chain and the
> filter must be called in such a way that it knows where to find the
> "home" directory since the command needs to read a configuration
> file in ~/.mailfilt.rc.
/srv/vmail/$DOMAIN/$LOCALPART/ is the home directory allowing for
such things as sieve scripts etc for virtual users. I am not sure
whether this actually works yet.

-- 
martin;              (greetings from the heart of the sun.)
  \____ echo mailto: !#^."<*>"|tr "<*> mailto:"
net at madduck
 
spamtraps: madduck.bogus at madduck.net
 
"first get your facts; then you can distort them at your leisure."
                                                       -- mark twain
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