[Dovecot] [OT] How do I convert maildir to bsmtp format?

[Stan Hoeppner]

This request for assistance is a train wreck, with cars strewn
everywhere, chaos ensuing, the carnage preventing everyone from being
able to see what's actually going on...

On 10/7/2012 2:47 PM, Marc Perkel wrote:
> Here's what I'm trying to do. I have a spam filtering operation as a
> front end for other servers. I've created a virtual server for spam
> storage where the user will be able to log in using squirrelmail/dovecot
> to review and release their spam. The email is stored in maildir format.

So you're trying to somewhat duplicate the functionality of a Barracuda
or other AS gateway appliance, with vanilla SM and Dovecot with very
little modification.  Good luck with this.  You're going to need to
write a pretty complex shell or perl script to do most of the work, and
call it from the SM "release button" routine.

> Piecing it together I can use squirrelmail to pipe the email into
> something so that if a use finds a false positive they can hit the
> "release" button and the message is sent on to the recipient.

> Squirrelmail sends the message as you would receive it as stored in
> maildir format.

SM only sends messages via SMTP submitted to the SMTP relay host
specified in the config file, or via dropping to the local MTA via
stdin/out.  Maildir is a mail storage directory and file format
protocol, not a transmission protocol.  It's physically impossible to
"send" a msg in maildir format, or mbox, or dbox, etc.  The format of
the SMTP headers and message body is plain text, possibly with MIME
encoding.

So what you really mean is you need a way to read a maildir message
file, scrape the recipient address, strip all of the AS headers you've
inserted, drop this 'new' message to the MTA, which sends the message to
the recipient.  When it arrives it appears never to have been molested
by your AS software, with only the proper headers and original body.
Then your script needs to check the log for successful delivery (250),
then send the proper commands to dovecot to log into the account as the
user and delete the message.  I can't begin to estimate the amount of
coding and testing required here, but it will be high.

> I need to take this format and translate it to send it on to the user.

Translate it?  I've never used maildir, but I can't imagine the on disk
message file contents need "translating".  See above.

> Wondering what is the best way to do that. Something that translated it
> into bsmtp format would be great. I'm sure thare must be something out
> there. I just haven't found it yet.

BSMTP isn't a file format.  It's a simple Mail User Agent with some
unique capabilities.  Given you already have an MTA on the host, why
would you need BSMTP to submit or deliver the msg?  You simply need to
learn the proper commands to submit mail to your local MTA.  With
Postfix you'd use postdrop or the sendmail compatibility command which
use stdin to read the message.

My no BS assessment and recommendation are that you're likely in way
over your head here (and don't realize it yet), and you need to focus
your efforts on locating an integrated FOSS solution, or even a
commercial solution, to fit your needs.  I seem to understand better
than you what is required to pull this off, and I wouldn't touch this
project with a 50 ft pole.  I simply don't have the coding skills for this.

-- 
Stan