Hi,

Is the only way to send an email to an external filter to use the xfilter command? The reason I ask is that I would like to be able to send a message to a filter and get the external filter result back on stdout or as its exitcode.

My particular challenge: I have a quick little python program that extracts URLs from an email message, performs a URI rbl lookup on them, and adds a header back to the email containing how many were listed (hits) and how many weren't (misses). Maildrop uses a regex to pull the header info out.

## Code snippet xfilter "/home/vmail/URLscanner.py"

/^X-SURBL:.*Hits=([0-9]+), Misses=([0-9]+)/ HITS=$MATCH1 MISSES=$MATCH2 if ($HITS > 3 ) { to "$DEFAULT/.URLscanner/" } #### There are two (at least) issues I have with this. 1) I would prefer not to change the email by adding a header, so it can be used for training a spam filter later. 2) Why send the entire email back when I only need a single integer reply? If maildrop would let me pipe a message to a filter without requiring that the entire message be handed back, I could have the filter print the hits to stdout and do this:

if (`/home/vmail/URLscanner.py` > 3) { to "$DEFAULT/.URLscanner/" }

That seems much simpler and cleaner...

So. Why is there no facility in Maildrop to interface with external programs where either their exitcode returns a useful, non-zero number or where their stdout contains filter information but not the message itself. Procmail has this, and I have found it very useful. Wouldn't it be a logical addition to put this functionality into Maildrop?

Please consider giving us an option where a message is piped to an external filter but where stdout is not expected to be the message but rather a report on the filter results, and where the exitcode can be non-zero and used for filtering decisions. Given the fact that a Google search reveals several "wrappers" people have made for external filters (for example, http://www.hodgman.org/dick/linux/configure-dcc-for-maildrop.html for DCC), I don't think I am the only one who would appreciate this.

Jeff