From: Hugh Sasse <hgs@...>
Date: 2005-12-01T05:00:09+09:00
Subject: Re: Exim mail filter in ruby

On Thu, 1 Dec 2005, chrisjroos@gmail.com wrote:

> In exim, I create a transport that uses a pipe to send the email to my
> shell script.  I also create a router that sends every mail that exim
> processes to my transport (providing I haven't already processed it).
> 
> My shell script reads the email from stdin and parses it based on some
> custom rules.
> 
> If it passes the rule checks it can be sent back into exim.  This is
> achieved by writing to the stdin of the exim command with some
> additional parameters.  Once I've given the email back to exim, I want
> to check for data on it's (exim command) stdout and stderr so that I
> can log any problems.

OK, sounds pretty std.
> 
> The interaction with exim is straight from the exim book and all works
> ok.  The question I have is really about the best way to deal with
> piping data to/from different processes within ruby in addition to
> trying to understand what's going on better.

I needed to understand where the data was flowing: that's why I
asked about how it interacted with exim.
> 
> I did use IO.popen to start with and can't now remember the problems I
> had, probably just ignorance on my part..

then I think what I wrote should work.  Maybe give it a spin or
compare it to the version you used unless you threw it out already
:-)
> 
> Chris
> 

        Hugh