On 2021-06-22 at 05:11:13 UTC-0400 (Tue, 22 Jun 2021 10:11:13 +0100)
D.C. Ebdon <[email protected]>
is rumored to have said:
Hi there
I'm hoping to 'fix' an issue with some software I have to use for work
that
can't/won't be fixed in the software itself.
In general, a MTA is a very poor place to try to fix problems created by
mail generators that are badly designed.
Basically the software sends
(in the space of a few seconds) two emails with an attachment apiece,
where
really there should just be one email with two attachments.
The emails are already routed through my locally hosted postfix relay
on to
Gmail and this works really well.
I was hoping to use milter to detect the two emails heading to the
same
recipient within a few seconds of each other, fold them into one email
and
send them on to gmail.
This is a bit like what some mailing list managers (e.g. GNU Mailman) do
when merging messages into 'digests' containing multiple messages. It is
worth noting that mailing list managers are NOT milters, but rather
accept delivery of mail and then re-inject modified or merged mail
later. The Milter interface operates 'live' on individual messages as
they are being offered and accepted for delivery, and it is a very poor
fit architecturally for correlating multiple messages and performing
intentional delays.
If someone was able to help with setting this up I'd be really
grateful.
I can't offer significant assistance but I do have a couple of
suggestions:
1. Don't make any milter do the complex multi-message part of this.
Figure out how to detect possible members of message pairs and divert
those to a local mailbox, then use Something Else to bundle up the
messages and re-inject them. Milter has no concept of handling multiple
messages as related objects.
2. If you are committed to using a milter for this, you need to
recognize that no existing milter will do it without some degree of
programming effort to modify/enhance the milter to add backend queueing
and re-injection which you will need to design. The most widely-used
milter I know of which enables such enhancement without excessive pain
is MIMEDefang, which is configured by way of creating Perl subroutines
which are called at the different phases of the Milter API. MIMEDefang
is the core platform for some very sophisticated mail handling systems.
Its original author, Dianne Skoll, has also forked a radical rewrite of
it called Mailmunge which I expect could also be a platform for your
needs.
In the end, I think your best option is just to live with it or find a
way to fix the problem *before* it turns into 2 messages that should be
one.
--
Bill Cole
[email protected] or [email protected]
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire
