On Wed, 05 Jan 2000 10:30:24 +0100, Thomas Stridh <[log in to unmask]>  said:
> My question is how can I detect that a mail is containing a attachment
> and how can I remove it from the stream, change it and replace it in the
> stream again?

This is a lot harder to do correctly than it looks, especially for
mail like this one, which has a digital signature attached to it.
Modifying the body will invalidate the signature.  In addition, if you
are trying to deal with a MIME multipart/alternative or similar,
trying to remove the "right" bodypart can be.. umm... interesting.

You might want to ask yourself *why* you are trying to remove
attachments, and if there's another way to address the problem.

If you're trying to limit oversized mail, the SIZELIM= parameter is
probably what you *SHOULD* be using, as it will also fix oversized
non-attachment mail.

If you're trying to security-check or virus-check mail, I recommend
you do that in your mail hub using a seperate software package, and
*not* removed attachments that are found problem-free.

In any case, removing an attachment will probably result in lots of
people complaining "I can't read the attachment, it seems to be
missing".  You will even get complaints from people who usually don't
like attachments.

Re-inserting a modified stream may get you into serious trouble -
consult a qualified lawyer regarding your liability.  That's just a
little *too* close to real-time revisionism, and probably worse than
simply rejecting/bouncing the note back with some explanitory text of
why it wasn't posted to the list.

And rememer - attachments aren't *inherently* evil, there was a REASON
why MIME was ever invented.  Those of us who were around in the pre-MIME
days remember 'uuencode' and all the OTHER ad-hackery that MIME was
designed to fix.....

--
                                Valdis Kletnieks
                                Operating Systems Analyst
                                Virginia Tech