[Dovecot] Feature Request - wild idea - folders for executing programs

[Marc Perkel]

Timo,

I have a wild idea for a feature that is somewhat unusual, would be very 
powerful, and easy to implement. What I want is ...

Special folders that when someone drags a message into them - it pipes 
the message into a program.

The reason I want this is - for example - reporting of spam. Suppose you 
want everyone to have a spam-missed folder so that if a spam gets 
through then the user drags it into the spam missed folder. But instead 
of storing it there it executes a program and pipes the message into it. 
In this case a learner program for the spam filter. The folder would be 
"write only" and attempting to read the folder would generally look like 
it was empty. Setup would look like this:

executable-folder spam-missed {
  command = /usr/bin/sa-learn spam
  user = spamd
  group = spamd 
  create_folder = yes
  accounts = *
}

The "create_folder" command says to add the folder to the users lists 
whether or not it is physically there. The folder appears even if there 
is no real folder. If it is "no" then it only exists if there is a real 
folder. The "user" and "group" is of course the UID and GID to run the 
"command" as. The "accounts" determines which accounts are affected. 
Default is everyone.

Other uses is to control blacklists and whitelists. Dragging a message 
into the blacklist folder runs an executable that adds the sender to a 
blacklist, or a whitelist, or controls settings etc.