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package: x2goclient severity: wishlist

The current way of client-side printing is rather error-prone (see various complaints on the mailing lists lately), also, it requires the user to be in the fuse group on the server. Which opens the can of worms that the user can now also use the built-in file sharing, which may not be desirable in all circumstances.

Therefore, I would like to suggest the following as new method of printing:

• x2goclient opens an SSH tunnel: -R<somenumber>:127.0.0.1:<someothernumber>
  • <somenumber> should start at a number above 1024, obviously, and a mechanism must be in place that determines a free port number, then uses that.
  • <someothernumber> should also be a number above 1024, starting at a fixed base number and incrementing with each user/session (similar to X2Go session numbers).
• on the server, CUPS-X2GO creates a PDF (optionally, compressed using gzip, bzip2 or xz - information about the compression method used could be conveyed in a PJL header comment field) and streams it to socket://127.0.0.1:<someothernumber>

I'm assuming the following two steps are a non-issue for Mac OS X and Linux, as CUPS is used natively there, and all we have to do there is connect the two CUPSes via a simple portforwarding.

• On Windows, x2goclient pipes the incoming data either directly as a stream, or via a temporary file, to a PDF viewer, which (in the simplest case) is set to automatically print to the default printer
  • optionally, we could pop up the print dialog, though this will add more complexity
• for ease of use, we should either ship SumatraPDF (a free PDF viewer that can be automated via command line options) with x2goclient, just as we currently do with pulseaudio and vcxsrv, or integrate the relevant parts of SumatraPDF directly into x2goclient, if based on the same programming language, and being licensed unter terms compatible with ours.

1. This eliminates the need for having users in the FUSE group to merely print a document,
2. also, if we can get SumatraPDF to accept the bitstream, it would even eliminate the need for a temporary file on the client,
3. lastly, by shipping a PDF viewer/printer, we make it easier for the user by providing a sane default (like we do with vcxsrv - users still can use a different X server if they choose to, but they don't have to download one manually first and worry to get the configuration right).

Portable version of SumatraPDF is here: https://kjkpub.s3.amazonaws.com/sumatrapdf/rel/SumatraPDF-3.0.zip Sources are here: https://github.com/sumatrapdfreader/sumatrapdf

• -Stefan

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