On Fri, 2013-04-05 at 16:51 +0100, Mark Goodge wrote: > Exim's job as a Mail Transfer Agent is to transfer mail. The same
> applies to every other MTA. It's what they're for.
>
> If you want a Mail Editing Agent, then these are available. Some of them
> may even be available as an external filter through which an MTA, such
> as exim, can pass mail.
And this is exactly what the OP asked for.
There are several ways to do it. In terms of decreasing "ease" (in my
opinion) of application:
1. A transport filter applied at the mailbox delivery level, or
1a. A pipe transport to a script/program which strips the necessary
content and delivers the message to the mailbox
2. A system filter applied to all messages which calls a pipe
3. A reinjection transport a la the way Amavis, SpamAssassin used to be
called
I suppose it *could* be done in either the DATA or post-DATA ACL using
readsocket, but... that's tinkering with content "in flight" and should
probably be avoided.
I should point out though that deletion of HTML MIME parts could
potentially render a message completely empty (or only contain a plain
text part saying "Your mail client can't see this message", or similar),
which seems to me to be to be an objective which is less than desirable.
Paul, if you're absolutely convinced this is a path worth following and
will not adversely affect your end users in any way then I see no
technical reason why you shouldn't try. I, however, would not - for the
content-based reason I set out above.
