IPP> notification methods

[pmoore at peerless.com]

So are we agreed that mandating a machine readable form is needed - Yes? I mean
that if a device does a machine readble method it MUST do at least INDP.




Michael Sweet <mike at easysw.com> on 07/21/2000 08:48:58 AM

To:   pmoore at peerless.com
cc:   ipp at pwg.org (bcc: Paul Moore/AUCO/US)

Subject:  Re: IPP> notification methods



pmoore at peerless.com wrote:
>
> 1.mailto and indp are used by clients for totally different
> purposes - you can do things with indp that you absolutely cannot
> do with mailto and vice versa. They are not overlapping they are
> complimentary. Therefore there is no bloat issue as such

I didn't say mailto and indp would cause bloat - in fact I agree
with you.

However, if the PWG does not mandate one or more required methods
then a client will be required to support them *all*, which will
cause bloat.  Requiring a minimum level of notification support
(including one or two required methods) will prevent this from
happening.

> ...
> 3. I am surprised that CUPS would want to use mailto from the
> actual printer back to the cups end user. I would have thought

Nope, that's not what we would do.

For our IPP backend we'd probably use indp or polling.

> ...
> 4. even if we mandate mailto, not all printers will support it. In
> order for it to work the printer must have its SMTP gateway
> configured by somebody. In some cases this will not have been done
> so the mailto method wont work - interesting question about how a
> printer should deal with this case. Presumably it must not say it
> can do mailto - or perhaps it will accept the requests and throw
> them away. Clients will always have to be smart.

This is an interesting point - it would be easy to return an error
from a create-subscription operation, but what would we return from
a print-job or create-job?

> ...
> 7.Mandating a method does not gurantee interop. THe two methods do
> totally different things. If my client needs machine readable
> notifications (for example I have a rendering pipeline driven by
> page complete messages) then telling me that mailto is available
> does nothing to help me. Its like saying "we have mandated SMTP why
> the heck do you want to do HTTP" - they do different things.

I'm not suggesting that mandating email alone will be sufficient;
likely we need to mandate at least one machine-readable method as
well.  However, in practical terms email is the method that will
gain IPP the most visibility and acceptance, with the other
methods being supported as demand grows.

--
______________________________________________________________________
Michael Sweet, Easy Software Products                  mike at easysw.com
Printing Software for UNIX                       http://www.easysw.com