[cups.general] Spool only

[Johannes Meixner]

Hello,

On Mar 21 11:26 Michael Sweet wrote (shortened):
> Nathaniel McCallum wrote:
> > We just finished a major upgrade from AIX 4 to Linux (thus from lpr to
> > CUPS).  We are maintaining an old program that was printing control
> > characters and PCL stuff directly: lpr was just spooling.  How can we do
> > this in CUPS?  ie. lp/lpr would spool directly to the printer with no
> > filtering, etc...
> 
> Setup a raw queue ("-m raw" option with lpadmin) and enable the
> application/octet-stream type in /etc/cups/mime.types to allow for
> raw data to be printed.

Great!

I never had the idea to acivate application/octet-stream only in
/etc/cups/mime.types but leave it disabled in /etc/cups/mime.convs.
This allows printing of arbitrary data only for raw queues
and for queues with a "System V style interface script"
but not for queues with full CUPS filtering using a PPD file.
The only minor drawback is that there is no longer any
"client-error-document-format-not-supported" error code.
Printing unsupported application/octet-stream data via a queue
with full CUPS filtering fails silently for the user
and in /var/log/cups/error_log there is
-------------------------------------------------------------------
E ... Unable to convert file 0 to printable format for job 123!
I ... Hint: Do you have ESP Ghostscript installed?
-------------------------------------------------------------------

In contrast if application/octet-stream is activated in
/etc/cups/mime.types and in /etc/cups/mime.convs,
raw printing is done as fallback if no other mime type applies
even for queues with full CUPS filtering using a PPD file.
This way any user can accidentally print tons of sheets with
meaningless characters when sending unsupported binary data
(e.g. *.doc files or whatever proprietary format) to CUPS.
An explicite printing option "-o raw" is possible in any case
to enforce raw printing when the user really wants it.


Kind Regards
Johannes Meixner
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