Re: SANE default scanner
On Mon 27 Jul 2020 at 19:39:25 +0200, Nicolas George wrote:
> Nicolas George (12020-07-27):
> > Well, in between explaining why all the answers I got do not match the
> > question, I RTFS, and it seems indeed it is not possible with SANE. What
> > stupid design.
> >
> > As for the hpaio backend, it relies on CUPS to find networked printers,
> > but CUPS will not be always running. What stupid design.
>
> These are now:
>
> https://gitlab.com/sane-project/frontends/-/issues/18
> https://bugs.launchpad.net/hplip/+bug/1889109
>
> I predict that SANE will blame hpaio and hpaio will not care that people
> do not want to run CUPS needlessly.
The assertion is:
libsane-hpaio relies on CUPS to detect networked all-in-one
scanner-printers. That means that if CUPS is not running,
networked devices are usable by specifying the URL, but they
will not be detected.
We may test this assertion as follows:
1. Install Debian with the base system only.
2. apt install libsane avahi-daemon.
3. brian@t5730sid:~$ scanimage -L
No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).
brian@t5730sid:~$
4. brian@t5730sid:~$ dpkg -l | grep cups
brian@t5730sid:~$
5. apt install libsane-hpaio --no-install-recommends
6. brian@t5730sid:~$ dpkg -l | grep cups
ii libcups2:i386 2.2.10-6+deb10u1
brian@t5730sid:~$
7. brian@t5730sid:~$ scanimage -L
device `hpaio:/net/envy_4500_series?ip=192.168.7.235&queue=false' is a Hewlett-Packard envy_4500_series all-in-one
brian@t5730sid:~$
Contending that libsane-hpaio relies on CUPS to detect scanners appears
to be based on a misunderdstanding of the code in hpaio.c. Most people
would take CUPS to mean 'apt install cups' and, as we see, cups-daemon
is not running.
Game, set and match.
--
Brian.
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