At one time, I believe the Set 2 Ops proposal included an 'any' out-of-band
value. But I don't see it in the spec anymore. 'Anyway', I'd like to
raise this issue again, since we have run into this problem again in
product development.
The key place where we need the 'any' out-of-band value is in
"document-format-supported". Some IPP Printers are actually proxy gateways
to downstream print services of some kind. It's not always possible to
know what document-formats are supported downstream. One example comes
from the IPP model document itself: a Printer can represent a logical
device such as "a gateway into an online document archive or repository".
The archive or repository may "support" any document format. But there is
no way to indicate this in IPP.
Lacking an 'any' value, the best solution (hack) we have come up with is to
respond with "document-format-supported" (if applicable) containing
'application/octet-stream' plus whatever "document-format" the client might
have supplied in the request. But this could be confusing to some clients,
and is in direct violation of the spec: "The values of all other Printer
object attributes (including "document-format-supported") remain invariant
with respect to the client supplied document format..."
Could you discuss this in San Fran? I will try to make at least part of
the telecon tomorrow.
-Carl