moving attached (embedded) email to mail folder

[Amedee Van Gasse (ub)]

On Sat, May 29, 2010 17:45, Graham Todd wrote:

> I think your problem has got more to do with .eml files being a
> Windows-only creation and Microsoft doesn't release the source code for
> its file formats, so people dealing with free software would be
> opening themselves up to litigation.

Graham,

Thank you for your comment, but I am afraid that your Microsoft bashing is
unjustified on this occasion.

The link you gave is about MIME Base64 encoding, which is well documented
in RFC 1421 and RFC 1521. The first RFC was written in 1993, long before
Microsoft ever wrote or purchased an internet email client.

Most current email clients (on Linux) are perfectly capable of detecting
and decoding Base64 encoding. No problem there.

My question was about emails that were "forwarded as attachment". They can
be Base64, quoted-printable, us-ascii, or any other MIME encoding. Just
try it with your own MUA on Linux: forward this email to yourself, not
quoted but as attachment. When you have received, try to detach the
encapsulated mail and put it back in the mail system. You can't.
The same happens with emails that are encapsulated by SpamAssassin. This
was in fact one of my primary use cases: to recover mails that were
wrongly classified as spam. So no Microsoft involved at all.

The reason why it is possible in MS Outlook, is that it has a lot of bulky
file type recognition. It needs that to process various "special" emails
like meeting requests. Programatically Outlook tries to map every message,
file or attachment it encounters to an instance of the Outlook.Item class
(or one of its subclasses like Outlook.Mail, Outlook.Contact,
Outlook.Note,...). Any Outlook.item object can (theoretically) be moved
anywhere inside Outlook mail folders.
If Outlook can't map a file or attachment to an Outlook.Item, it passes
the file handler to the operating system who performs the default action:
open MS Word for .doc files, image viewer, url handler to launch the
default browser, whatever.


I think that you confuse with TNEF (Transport Neutral Encapsulation
Format) aka winmail.dat, which is used by MS Exchange in combination with
MS Outlook. I am aware of the tools for decoding winmail.dat attachments,
I even have such an extension in Thunderbird. But that was not my
question.


I'm sorry if this sounds like I'm lecturing you. Perhaps I am, but with
good intentions.

Kind regards,
Amedee Van Gasse