[cups.general] Discovering IPP queues

[Michael Sweet]

Tim Waugh wrote:
> I'm developing a feature for a CUPS administration tool
> (system-config-printer) which uses libcups, and I'm trying to work out
> how it needs to be done.  I've looked through some of the IPP standards,
> but I find them quite confusing. :-(

:)  There is no official support in IPP for driver selection or
a standard for getting the correct device URI...

However, there *is* a relatively new SNMP MIB (Port Monitor MIB)
which allows you to get the correct device URI and 1284 device
ID so you can setup a queue.  This will be supported by the SNMP
backend as soon as we find a printer that supports it...  Supposedly
support for this MIB is required to label the printer as "Vista-
ready"...

On a more practical level, very few network printers actually
support IPP properly so even the new Port Monitor MIB may point
to AppSocket or LPD as the protocol of choice...

> If I have just the host name of a device that claims to support IPP, is
> there anything I can do to obtain a valid device URI that can be used to
> print to it?

All you can do is probe using common URIs, which with some bad IPP
implementations can lead to lockups (which is why we took the probe
out of the SNMP backend...)

> Alternatively, if the user also needs to supply a queue name, is there
> any way of combining a host name and queue name to form a valid IPP URI,
> or does it just depend on the device?

What we do on Mac OS X is just concatenate the host and queue names,
allowing the user to enter /'s in the queue name as needed.

-- 
______________________________________________________________________
Michael Sweet, Easy Software Products           mike at easysw dot com
Internet Printing and Publishing Software        http://www.easysw.com