To pursue "+opczip" or not to do so?

[rjelliffe at allette.com.au]

> If we give up the "+opczip" convention, what will we lose?  We will lose
> fallback to generic processing of OPC packages for unknown media types.

We only absolutely lose that if there is no way for a system to inspect
the file and know 1) it is ZIP, 2) it is OPC. I believe that an OPC
package can do this by seeing first the 'PK' magic number, and second the
presence of _rels/.rels

And generic processing is more useful for the convenience of developers
not application users. However the developers are smart enough to look and
see.

IIRC most systems use a combination of mime and magic number to figure out
the processing to run. And I don't know that most dispatching systems
allow wildcard matching on the MIME type.

All that being said, I think if we went down this road it would be better
to have
  +zip
  +opc+zip
if the MIME syntax allows it. This would allow a convention to be
developed where
   application/XXX+opc+zip
could be treated as a first fallback as
   application/opc+zip
if there is no handler for , and as a second fallback
   application/zip
if there is no OPC handler.

In the same way,
   application/YYY+xml
would be treated as its first fallback as
   application/xml
which is the intended behaviour.

Cheers
Rick Jelliffe