I have a question about the use of multipart/digest and how other
mail user agents treat this content type. There are a couple of
cases where we are considering using multipart/digest, and I was
wondering (1) how other mail clients out there would handle it
and (2) what people's opinions are about how to handle these cases.
The first case is when a user selects several messages from the
header list in the client and drags and drops them as a group
onto the attachment pane of the Compose window. Since we are
on a Unix system, we package up the messages in the Unix mbox
format with "From " lines at the beginning of each message. This
is so that if they are dropped on the file manager, they will
be saved as a Unix mailbox; otherwise, we would lose the ability
to type it as a mailbox.
But when the buffer is dropped on the attachment pane of our mail
client, we have control over how the data should be represented.
We could repackage the data and turn it into a multipart/digest,
where each of the dropped messages would be a message/rfc822, or
we could keep the data as it was dropped and create something like
a text/x-sun-mail-file.
On the receiving end, double-clicking on an attachment with the
type text/x-sun-mail-file would be just like opening up a mailbox
from the file system. So if we were to send it out as multipart/
digest instead, then when the user double-clicked on the attachment
we would convert it to the mailbox format so that it could be
opened as a mailbox. The disadvantage is that it might break the
ability of some older unix mailers to open these attachments as
mailboxes; but the advantage is that it might allow MIME-compliant
non-Unix mailers to have an easier time reading these messages.
Ideally, other MIME-compliant mailers would also open multipart/digest
messages as mailboxes (however they represent open mailboxes) and would
be able to save them as mailboxes in their native format. What I would
like to know is how many mailers would handle multipart/digest in a
reasonable way?
The second (very similar) case is when adding a mailbox attachment from
the file system. Again, in this case, each message has a Unix From line
at the beginning of each rfc822 message. Should we convert it to a
multipart/digest or should we leave it alone and call it text/x-sun-mail-file?
If we made it a multipart/digest, then they would lose the information
contained in the From headers when they receive it on the other end, but
more mailer clients may be able to read the messages as messages.
On the one hand, we would like to interoperate with as many mail clients
as possible, but on the other we don't want to leave users of our older
mail clients dead in the water. Are there any mail clients out there
that would treat a multipart/digest as a mailbox? How do other mailers
handle the problem of sending around mailboxes, along with the associated
interoperability issues?
Thanks,
John Togasaki
john(_dot_)togasaki(_at_)sun(_dot_)com
SunSoft