Why Attachment field as byte array?

[Julian Boot]

The Attachment field in the latest ticker spec (3.0) is defined
as a byte array.

   Attachment     opaque   A MIME-encoded addition to the message.
                           Multiple attached objects SHOULD be
                           encoded using the multipart/mixed MIME
                           type.

                           Note that this field is an opaque type,
                           and thus an array of bytes.  therefore, it
                           is not necessary to transform attachments
                           (using, for example, base64) as is the
                           usual practice for email.


However, it is also MIME encoded.  Given that MIME is intended to
support sending binary information as text, is there any reason I
am missing why the Attachment filed should not be defined as being
a string?  I must admit that my knowledge of MIME is user level, not
implementaion level...

For instance, if an application receives and Attachment in a notif,
how does it determine if its a MIME string, or a binary JPEG?  Or
is that just part of the magic MIME handlers are expected to cope
with?

-J

----
          julian boot <julian at dstc.com>
))X((     senior research scientist
elvin     http://elvin.dstc.com