Re: SANE default scanner

From	Nicolas George <george@nsup.org>
Newsgroups	linux.debian.user
Subject	Re: SANE default scanner
Date	2020-07-28 00:00 +0200
Message-ID	<Axjk6-2WD-3@gated-at.bofh.it> (permalink)
References	(5 earlier) <Axd50-7M3-11@gated-at.bofh.it> <AxdeG-7Pd-23@gated-at.bofh.it> <AxdRo-8i6-17@gated-at.bofh.it> <Axekq-8rR-27@gated-at.bofh.it> <AxixH-2FX-7@gated-at.bofh.it>
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Stefan Monnier (12020-07-27):
> Indeed.  And given SANE's design, there shouldn't be much need for it:
> it assumes that either the scanner is local (via a hardware-specific
> driver, hpaio being one of them) or it's remotely accessed over the SANE
> protocol, in which case it uses the DNS-SD protocol to find it.
> 
> The problem is with scanner that are remote but using a "local driver"
> (local to the client rather than local to the scanner).

This is a sadly classic pattern in Libre software: "not my problem, it's
the other project doing it wrong".

Sorry guys, you're BOTH doing it wrong:

hpaio, you should not rely on a print server to detect scanners, even if
you're made by a company that first came to this business through
printers.

SANE, since you accept third-party back-ends, you should assume some
will get it wrong and have workarounds ready.

> I suggest you open a feature request on the SANE's issue tracker.

Already did. And to hplip too.

> Who knows, maybe this can even be solved already by somehow tweaking the
> DNS server to advertize your hpaio device?

No, it can't, that's pretty obvious looking at the source code:

- The only way to have SANE-using applications see the scanner is that
  hpaio detects it.

- The only way to have hpaio detect the scanner is to have CUPS running,
  the corresponding printer configured and hpaio allowed to connect to
  it.

Both these points are design mistakes.

Regards,

-- 
  Nicolas George

Thread

SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 12:00 +0200
  Re: SANE default scanner Georgi Naplatanov <gosho@oles.biz> - 2020-07-27 14:00 +0200
    Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 14:50 +0200
      Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 15:00 +0200
        Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 15:00 +0200
          Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 15:30 +0200
        Re: SANE default scanner Hans <hans.ullrich@loop.de> - 2020-07-27 15:10 +0200
          Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 15:30 +0200
      Re: SANE default scanner Georgi Naplatanov <gosho@oles.biz> - 2020-07-27 15:10 +0200
        Re: SANE default scanner Reco <recoverym4n@enotuniq.net> - 2020-07-27 15:30 +0200
        Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 15:40 +0200
          Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 16:00 +0200
            Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 16:30 +0200
              Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 17:40 +0200
                Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 18:10 +0200
              Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 17:40 +0200
          Re: SANE default scanner Georgi Naplatanov <gosho@oles.biz> - 2020-07-27 16:50 +0200
            Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 17:00 +0200
              Re: SANE default scanner Stefan Monnier <monnier@iro.umontreal.ca> - 2020-07-27 17:20 +0200
                Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 17:30 +0200
                Re: SANE default scanner Stefan Monnier <monnier@iro.umontreal.ca> - 2020-07-27 18:10 +0200
                Re: SANE default scanner Stefan Monnier <monnier@iro.umontreal.ca> - 2020-07-27 18:40 +0200
                Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 19:20 +0200
                Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 18:40 +0200
                Re: SANE default scanner Stefan Monnier <monnier@iro.umontreal.ca> - 2020-07-27 23:10 +0200
                Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-28 00:00 +0200
                Re: SANE default scanner Stefan Monnier <monnier@iro.umontreal.ca> - 2020-07-28 00:30 +0200
                Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-28 14:20 +0200
                Re: SANE default scanner Stefan Monnier <monnier@iro.umontreal.ca> - 2020-07-28 16:20 +0200
                Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-28 21:30 +0200
                Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-29 11:20 +0200
                Re: SANE default scanner <tomas@tuxteam.de> - 2020-07-29 12:10 +0200
                Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-29 20:30 +0200
                Re: SANE default scanner <tomas@tuxteam.de> - 2020-07-29 21:40 +0200
                Re: SANE default scanner <tomas@tuxteam.de> - 2020-07-28 09:40 +0200
                Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 18:40 +0200
                Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 18:50 +0200
                Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 19:10 +0200
                Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 19:20 +0200
                Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 20:00 +0200
                Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 19:40 +0200
                Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-28 14:20 +0200
              Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 20:40 +0200
                Re: SANE default scanner Brian <ad44@cityscape.co.uk> - 2020-07-27 21:20 +0200
                Re: SANE default scanner Gene Heskett <gheskett@shentel.net> - 2020-07-27 21:20 +0200
      Re: SANE default scanner John Boxall <jboxall47@gmail.com> - 2020-07-27 15:30 +0200
        Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 15:40 +0200
          Re: SANE default scanner Liam O'Toole <liam.p.otoole@gmail.com> - 2020-07-29 00:00 +0200
  Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-07-27 19:40 +0200
    Re: SANE default scanner Siard <shiems@mailbox.org> - 2020-07-27 20:00 +0200
  Re: SANE default scanner Siard <shiems@mailbox.org> - 2020-07-27 19:40 +0200
  Re: SANE default scanner George Shuklin <george.shuklin@gmail.com> - 2020-08-07 17:20 +0200
    Re: SANE default scanner Nicolas George <george@nsup.org> - 2020-08-07 17:30 +0200

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