[Dovecot] Automatic expire on post-login

I need to clear two folder from Maildir at login.

Exatly, delete all mails older than 30 days on Trash and 1 day on spam folder.

I'm using dovecot 2.0 and I think about use a post-login script calling doveadm -u $user expunge but post-login scripts in dovecot 2.0 are very complex

Is there possible to get the environment vars like on dovecot 1.2 ?

I think this action must be done by expire plugin, but it isn't the work method if as I understand after read wiki2.dovecot.org about expire plugin, It run only with a cronjob.