Zdenek,
> On Aug 22, 2022, at 1:08 AM, Zdenek Dohnal via ipp <ipp at pwg.org> wrote:
>> Hi all,
>> Fedora user brought up an interesting question for me - whether user has some CLI tool for changing default options on the printer itself (which supports one or more of driverless standards - AirPrint, IPP Everywhere etc.), without going to printer's web interface.
Yes, IPP allows for this although most printers do not currently support it. Basically, the Set-Printer-Attributes operation is what you would use to set the "xxx-default" attributes (media-default, print-color-mode-default, sides-default, etc.), and you should expect that the printer will require authentication for the operation to succeed.
> IMHO it might be possible - printer supports IPP 2.0+, CUPS supports IPP as well and CUPS CLI tools, which work with CUPS, have an option for setting a CUPS server which they want to send the request to. Once the local user has the correct permissions (since IPP backend is run under root, my guess is root has at least some permissions...) it could be possible.
Running as root doesn't influence things - all authentication happens at the printer end.
> Is my understanding incorrect? Is there a different CLI tool which can do the trick? (maybe ipptool?) To be honest I'm interested how is IPP usually implemented internally in the printer - is there some CUPS version? Or HTTPD (Apache) with proprietary IPP support on the top of that? Or whole HTTP+IPP implementation is written as a new there?
Anything goes for printer firmware. There are some using CUPS and/or PAPPL, some using Apache, but most use a custom HTTP+IPP implementation.
________________________
Michael Sweet
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