[cups.general] Question on use of Class

Michael R Sweet msweet at apple.com
Thu Aug 16 13:01:08 PDT 2007


angelb wrote:
> Hello all.
> 
> I'm almost certain Class in CUPS is not designed for this...but I'll
> ask anyway. If I understand Classes correctly, its primary function is
> to group printer queues, clients print to the class, and job is
> printed by the next available printer in the Class....but I'm not sure
> if this is accurate or it could be used for other things. I've just
> started looking at the Classes feature so I could be wrong with my
> notion.
> 
> Can Class be used to specify what available printer(s) a specific cups
> client system can poll or see from the server? In other words, if I
> create classX, can I configure the client such that it only see the
> printers in the classX and not everything else?
> 
> If Class is not the right tool for the above situation, is there any
> function or configuration in CUPS can?

No, nothing standard in CUPS anyways.  However, nothing would prevent
you from adapting cups-polld to do this.

> Observation:
> 
> The list of members listed from the Classes tab is limited to 2410
> characters. Out of 515 ques, it only shows 482 comma-delimited que
> names. My printer queue names are 4 characters long and if you add the
> commas, that would make 2410 characters.
> 
> 2410 / 5(que name + comma) = 515

Actually, the buffer is 16k and contains hyperlinks...

> If you have other classes with less printer que, you'll have to scroll
> almost half-way across the window to see the members.
> 
> IMHO, the members field should be set to a maximum of 118 characters(a
> reasonable number of printer queues listed with the window maximized)
> and a "Show Next" tab to list the next set of printers.

That would be exceedingly difficult to do for all classes; it
would be doable when showing a single class, but then a simpler
approach would be to simply separate the member names with spaces
so that they wrap...

> Lastly, when sending a print job to a class, there is no indication as
> to which printer printed the job. So, if you have 20 printers in one
> ocation and they belong in LOCATION_Class, for example, you'll have to
> go to each printers to check for the printout.

Actually, the job-actual-printer-uri attribute *does* provide this
information, we just don't show it in the web interface at this time.

You can edit the jobs.tmpl template to add a conditional reference,
e.g.:

     {job_actual_printer_uri?<br>Printed on {job_actual_printer_uri}:}

-- 
______________________________________________________________________
Michael R Sweet                        Senior Printing System Engineer





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