> On Fri, 4 Jun 1999 11:34:30 +0100 (BST), you wrote:
> >You can't really tamper with the body of a message in a system filter.
>
> But I can _see_ the entire body of a message in a system filter?
> $message_body doesn't seem to do it.
What you can see is in $message_body and is the first part of the body.
You really can't do this in a system filter, you might be able to do it
in perl.
> >(b) You could write a transport filter for the local delivery transport.
>
> That would have to be C code compiled into exim?
No - its a filter process called within the transport - message in,
mangled message out. It could be a shell script.
> I'd like to see some way of piping entire messages through an
> arbitrary filter. This would faciliate removal of attachments, virus
> scanning, QP-to-8-bit-conversion and a bunch of other things. This
> mechanism should have possibilities to generate notification messages
> for both sender and recipient and to optionally fail delivery for a
> single or all recipients.
This can be done with a transport filter... mostly. To do things on a
per recipient basis the filter would need to be invoked on a per
recipient basis. This could get expensive in CPU usage etc.
Also changing the message size dramatically could have interesting
effects - if you do this within an SMTP transaction then the size
changing could upset things - I guess you need to turn off ESMTP.
> Maybe some kind of transport that doesn't do any deliveries but passes
> the message through some processing?
Putting everything through a BSMTP transport to disk and then post
processing it into another exim invocation is a method I have used
before (with smail) - it works very nicely! Its also more efficient
than a transport filter.
Nigel.
--
[ Nigel Metheringham Nigel.Metheringham@??? ]
[ Phone: +44 1423 850000 Fax +44 1423 858866 ]
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