Folks, this discussion has gotten so far away from its origin that we've
lost track of why we are having it.
The original problem is: how do I have my MIME handler automatically know
that it should hand a body part that has an unknown tag on it to the
generic XML processor?
We have explored many, many alternatives in detail. They all have
drawbacks, some of them severe. However, there is a simple solution that
involves no changes to any protocol *and* will stop this discussion so we
can move on with more interesting aspects of XML.
Proposed solution: every time the MIME handler comes across an unknown
media type, it looks in the body part and sees if it is XML. If it is XML,
add this media type to the "hand to the generic XML processor" list. If it
is not XML, add this media type to the "don't hand to the generic XML
processor" list. If you are really paranoid about missing something, clear
the latter list every so often.
Done. No changes to the naming schemes needed, no hoping that if the naming
scheme changes that all future media types follow it, no worrying about
'x-' names getting it wrong. Making these lists won't be that hard; there
are only 330 types in the IANA registry now, and that includes all of the
'vnd.' names.
Look inside and see if this media type seems to carry XML. This is what
automated systems are good at. As for us humans, we seem to be pretty good
at finding rat holes to go down...
--Paul Hoffman, Director
--Internet Mail Consortium