[FreeNX-kNX] FreeNX cups printing authentication

[Alastair Johnson]

Your problemis no longer with NX but with CUPS on the server. One of the 
filters in the chain used to produce the data to send to the printer is 
failing, and the error message and level of logging at that point in CUPS are 
particularly unhelpful in trying to track down exactly what or why. I think 
the system CUPS on our server was perfectly happy, but that the usermode CUPS 
started by NX failed with this error. This makes me think there's a 
permissions problem somewhere, but I didn't track it down. A workaround is to 
get the processing done at the client end using the client's CUPS drivers. I 
don't remember exactly how I did this and don't have my notes to hand, but I 
think I covered it on one of the earlier posts. It involves bypassing the 
nxclient call that displays the printer driver selection dialogue and sets 
the MODEL variable since you no longer need it, and changing the subsequent 
lpadmin arguments. These are towards the end of function cmd_node_addprinter 
in nxnode again.

The 'AuthType' part was an attempt to fix the authentication before I found 
out about changing the IPP url from localhost to an IP address or name. It 
was all part of the learning experience.

On Saturday 24 June 2006 13:12, Pieter Thysebaert wrote:
> Alastair Johnson wrote:
> > You need to modify /usr/bin/nxnode function cmd_node_addprinter() to
> > include the username and password when setting up the CUPS printer, and
> > change the host from localhost to the hostname or IP address. Change the
> > line: DEVICE_URI="ipp://localhost:$port/printers/$printer"
> > to:
> > 	DEVICE_URI="ipp://$username:$password@your_hostname_here:$port/printers/
> >$printer"
> >
> > I _think_ the change from localhost to actual hostname is needed because
> > CUPS uses token-based authentication for localhost instead of the usual
> > challenge-response methods. Normally this is fine, but since we are
> > port-forwarding to a non-local cups we need the challenge-response, so we
> > need something that resolves to the local machine but isn't localhost (or
> > 127.0.0.1 for that matter)
>
> Thanks for your reply, I can now see the printer !
>
> However, I've stumbled across a problem that you seem to have run into
> as well:
> All jobs printed on the NX server side are immediately cancelled ("Have
> you installed ESP ghostscript").
>
> In the archives, I found that you changed "AuthType Digest" to type
> Basic on the client side user cupsd.
>
> For me, this does not seem to make a difference.
>
> IPP_PORT=... lpr test.txt still produces errors like
>
> Unable to convert file 0 to printable format for job 7!
> I [24/Jun/2006:14:08:58 +0200] Hint: Do you have ESP Ghostscript installed?
>
> Do you know of anything else that needs some work before I can actually
> print ?
>
> Thx,
> Pieter
>
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