On Fri, 18 Feb 2011 07:23:35 -0800, Tim wrote: > Thanks for helping me to understand. I don't know if you're familiar > with LaTeX, but that's part of what daemon.py calls via subprocess, and > that is the underlying process I wanted the user to be able to interact > with. > I've used nroff but never LaTeX - however, my understanding is that its essentially a batch process. > When LaTeX encounters a problem it stops processing, asks the user what > to do (like abort/retry, kind-of), and does whatever the user says. The > daemon.py script handles that okay from the command line, but if I'm > understanding you this will be much harder if not impossible to > accomplish from a client communicating over a socket. > Are you sure it wouldn't be better to end the run, returning suitable error messages to the user, who would correct the input file(s) and rerun LaTex? > I thought that maybe I needed to fork the socket (somehow) so it could > listen after the message is sent, but it looks like it will be more > complex. > The easier way my be to give the user a login to a captive shell that's restricted to running LateX, an editor and little else apart from a results viewer. Bash and most decent editors can be restricted so the user can't start a second, less restricted shell, and the range of programs it can execute can be restricted by adjusting with $PATH.
You may also be able to find a menu program that can impose many of those restrictions by replacing the login's shell by the menu program. I do this as a matter of course: my menu program may get released one of these days but it's not currently on a fit state to publish. If you want to continue down the server path you should investigate popen. It is part of the os module. You could design the server so a suitable request runs LaTeX via popen, captures the stdout and stderr output, if any, and returns that and the LaTeX termination status code to the client as a response message. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | -- http://mail.python.org/mailman/listinfo/python-list
