Raw Print Server
 
Copyright © 2005, Chris Gonnerman
All Rights Reserved

INTRODUCTION

This is my implementation of a "Raw" print server. It allows a computer to pretend to be a "Socket API" or "AppSocket" print server, i.e. a network connected printer. In fact, this program can serve a number of printers, each with its own port, simultaneously.


CREDIT WHERE CREDIT IS DUE DEPARTMENT

This software would not exist without Sam Rushing's excellent asyncore module, nor would it exist without Steve Holden's excellent explanation of that module (in his book "Python Web Programming" from New Riders, a truly outstanding book that I can't recommend enough) from which I learned enough to write this server. I'm also indebted to Guido van Rossum for Python itself, which has made my life SO much easier, and to Mark Hammond for the win32all modules which are essential parts of the Windows version of the print server.


RELEASE NOTES

This is version 0.1 of the Raw Print Server. There are no installation instructions to speak of; I plan to write an install script to assist with getting the software up and running, but for now it's all manual.

You will need a working Python 2.x system to run the print server itself, and if you are installing on Windows you'll need a working set of the win32all modules from Mark Hammond (which you really ought to have anyway). To run the GUI properties program, you'll need a working PyGTK module set, and on Windows that means finding a compatible GTK+ runtime also.

Finding all of the above is left as an exercise for the reader.

sigh

Okay. If you are on a recent Linux system, or any of the BSD family, you should be able to install all of the above from your original installation media, or download them from the appropriate website for your distribution.

If you are running Windows, start by getting a recent Python build from www.python.org; follow the links from that site to the win32all downloads (currently somewhere on Sourceforge). After that, go to www.pygtk.org and follow their links to the downloads you need for Windows. Note that as of this time (October 2005), the GTK libraries normally used for the Gimp don't work with PyGTK (despite notes on the PyGTK for Windows site saying that they do), at least, not on Win9x. Get the runtime or development libraries referenced from the PyGTK for Windows site. If you already have the Gimp installed, uninstall the GTK+ libraries you got with it before installing the alternate runtime. My Gimp still works, so it must be okay, right?

REMEMBER, as it says in the legal bit at the top, this is all at your own risk and I'm not responsible if the software does harm, or simply doesn't work at all. I've made every effort to make it good, clean, reliable stuff, but there are NO GUARANTEES or WARRANTIES. You paid me nothing for it, how could you expect me to give you anything if it goes wrong?

After you get that stuff installed, find a folder to unpack the software into, and do that. I use C:\Program Files\RawPrintServer on Windows, but on Linux I'm not sure where the "right" place is to put it.

Run the rpsprops.pyw script first. It prompts you for the spool directory, logfile name (and path), and the printer(s) to support. These settings are saved to the configuration file (/etc/rpsrv.conf on Linux/Unix/BSD, C:\WINDOWS\SYSTEM32\rpsrv.conf on Windows).

I recommend the following on Windows:

Spool Directory  C:\WINDOWS\TEMP
Log FileC:\WINDOWS\rps.log

For Unixoids, use what you like. The proper place for rps.log is probably under /var/log, and you could either use a temp folder (/tmp or /var/tmp) or create a folder under /var/spool (probably a better place).

The printer definitions are created using the Add button in the GUI. You need to define a different port number for each printer; the "standard" port is 9100, but I've seen 10000 and 10001 used a lot also. The printer name on Unixoids is the standard LPR or CUPS name. For Windows, you can pull down a list showing the currently-defined "local" printers to select from.

Note that the Quit button in the GUI doesn't presently ask about saving. Don't forget the Save button!

If you don't have or want PyGTK on your system, you can easily create the rpsrv.conf file by hand; it looks like this:

spooldir = /var/tmp
logfile = /var/log/rps.log
printer = 9100, lp
printer = 9101, dotmatrix

Note that the "printer" directive can appear multiple times, each time defining a different printer. Blank lines are ignored, as are lines beginning with the # character. The GUI doesn't preserve comments, so if you create the file by hand and then edit it with the GUI, expect your commentary to disappear.

To start the server on a Unixoid system, just run RawPrintServer.py. It daemonizes itself automatically. RawPrintServer.py does not need to be run as root (except if you choose to use reserved port numbers), so for security reasons I recommend you run it as a regular user, preferrably one created just for the purpose. This is also left as an exercise for the reader.

For Windows NT/2000/2003/XP, use RawPrintService.py. Run it from the command line like this:

start RawPrintServer.py install

"start" may or may not be needed, depending on the version of Windows you are using.

After doing this, go look in the Services control panel interface, and you'll find "Raw Print Server" listed. Start it, and then (if you want) right-click and choose "Properties" and make the startup Automatic.

Presently there is no version for use on Win9x. This is a minor thing to create (mainly just strip the Unixoid daemonizing parts out of RawPrintServer.py) but I haven't done it yet.


FUTURE PLANS

I plan to create an installer script to make setting this whole thing up easier. I also intend to add a minor security feature to the program: an IP address "stem" that must be matched before a connection will be allowed. For instance, if the stem is "192.168.0.", then only computers in the 192.168.0.XXX subnet would be allowed to use the printer. This isn't a big deal if you have a NAT firewall, but otherwise it is probably necessary. No telling where your print jobs might come from...

I might even set it up to accept a list of such "stems" to accommodate those with more complicated networks.


CONTACTING ME

If you have questions, comments, or (I hope) enhancements regarding my Raw Print Server, please feel free to contact me at:

chris.gonnerman@newcenturycomputers.net

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