[exim-dev] Milter api

I really like the power exim has in its macros and string handling,
but I have always felt like we exclude ourselves from some nice
software options because we don't support the milter interface. For
instance, I am a beta tester for the opendkim project, and while I
like the built in DKIM support, I have a large system already setup on
the sendmail (older customer mail system) side with opendkim doing key
lookups from mysql. It would be easier to manage if I could also use
this same opendkim software configured in the same way across the exim
side as well. It simplifies my exim configuration some as well.

I spoke with a gentleman (Hilko) who had developed a local_scan based
milter interface as part of his thesis, this was back around 2006 when
exim 4.66 was current. He also had started working on an integrated
version. The local_scan version processed the whole message in one
chunk, whereas integrated support can be called at any point in the
ACL's that the sysadmin desires, depending on the function of the
milter(s). It's wrapped with EXPERIMENTAL_MILTER macros, so it can be
turned off or on at build time as needed.

1. The first question is if there is any interest in this kind of
functionality. Would a fully tested and documented patch be accepted
into exim core?
2. Undoubtedly it needs extensive testing especially WRT error
handling, I'm planning on doing a lot of that, and will also run it in
a test system and (if stable) in a production scenario for a while
before I ask Hilko to submit it.
3. Hilko is a damn good coder, and it's his (GPL v2) code, none of it
is mine. I'm just serving in the capacity of finding bugs, maybe
fixing them if they're simple.
4. I've not tested anything yet, only merged it into my local copy of master.

I've scanned the archives several times looking for conversation on a
milter interface in exim. I found nothing that indicates any
inclination by the core devs either for or against such an interface.
Any comments?
--
Regards...      Todd
I seek the truth...it is only persistence in self-delusion and
ignorance that does harm.  -- Marcus Aurealius