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Date: Sat, 16 Jul 2011 14:08:49 -0400
Subject: Re: Looking for general advice on complex program
From: geremy condra <debatem1@gmail.com>
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On Fri, Jul 15, 2011 at 3:47 PM, Josh English
<Joshua.R.English@gmail.com> wrote:
> Maybe not to the gurus here, but for me, this is a complex problem and I =
want to make sure I understand the real problem.
>
> All of this is in Python 2.7 and wxPython
>
> I have several XML files on a shared drive.
> I have applications on other machines that need to access this XML file.
> These applications need to read and write to this file.
> These applications need to a) be alerted to a file change, or b) monitor =
the file for changes and regular intervals.
>
> In my code, I have XManager classes (using a Singleton pattern) that read=
s each XML file into a tree (using ElementTree). The XManager class can rea=
d the file, make changes to the tree, and write the file as needed.
>
> Now I'm expanding to the multiple application level, and I think I unders=
tand what I need to do, and I'm unsure about the exact processes.
>
> I've been trying to have the XManagers check periodically if the XML file=
 they monitor has changed. Since I don't want to mess up the GUI with const=
ant hanging, I think I can use the thread or threading modules to create a =
recurring timed check, and then I need a separate check to see if the file =
is in use before reading or writing.
>
> I also need, I think, to have a way to check if the GUI is editing a node=
 before the XManager reads the file, so the thread needs to be interrupted,=
 or paused, because I don't know if threads would stop if a wxDialog is bei=
ng show modally or not.
>
> So, am I on the right track here?

I'd try watchdog[0] before I went to the trouble of rolling my own.

Geremy Condra

[0]: http://packages.python.org/watchdog/