things for msweet to add to his (next) book
null
nomail at nomail.invalid
Wed Nov 17 06:19:53 PST 2004
In article <1716-cups.development at news.easysw.com>,
Michael Sweet <mike at easysw.com> wrote:
> What kinds of examples are you looking for?
The nature of the *cupsFilter key (mentioned in a related thread) had me
pounding my head on my desk for a good three hours. The book doesn't
discuss the topic much and the error_log isn't any help since CUPS is
working correctly (i.e., the route it chose ... through the initial
filter only ... was technically correct). A discussion of what filter to
bind via *cupsFilter and why would be a useful investment in the book
(I've penned in notes to mine).
The other items that tripped me up were how to create routes in the
first place. Until one groks the singular nature of .convs entries
creating chains can prove distracting. Your response to another fellow
having similar "how do I create chains" type of query gave me the "a
ha!" info I needed to put that piece of the puzzle in place. To be
truthful the very nature of filters and the costing piece in .conv
implies that chaining is standard behavior. The only missing piece is
"how?"
The default thought that came to my brain when the notion of filter
chaining arose was the desire to simply specify A-Z routes in some file
somewhere as a single record. Write/work the description from that basis
and I think you'll connect with more people.
The only other piece of the puzzle that left me wanting was the question
you just answered. Namely, what errors can a filter return that will
block progression but not shut down the queue. Further what does CUPS do
with errors returned by a filter.
My first installation/test was a filter that crashed almost immediately.
*That* did shut off the print queue. That particular queue config looked
like this:
queue -> lone filter -> ... -> /dev/null
I'd also like to see an option in lpadmin to *read* the current config
of a given printer. Like this...
lpadmin -p foo --status
....or something along those lines. With a result along the lines of:
Printer: foo
<summary of the current state of all the lpadmin settable switches>
Best,
JR
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