Tkinter and asyncronous socket

[maxlosblob at gmail.com]

On 26 Nov, 13:42, Steve Holden <st... at holdenweb.com> wrote:
> maxlosb... at gmail.com wrote:
> > Hi all, I'm new to python and I've been spending the last week on GUI
> > that refresh its content based on data periodically coming from a
> > remote socket.
> > I succeded in doing it (thanks newsgroups and online manual!) using
> > theTkinter.after method to implement a busy wait on the socket (which
> > I had previously set to non blocking)
> > I should be happy with it, but on windows (application must be multi-
> > platform) the busy wait leads to a 100% CPU usage. I'm trying to
> > implement it the other way round: a "socket process" that updates a
> > label (or a queue object) in the GUI. I can't figure out how to do
> > this. Anyone can post hints? With some details, maybe?
>
> Processes are probably a bit heavyweight for this purpose: they create
> difficulties in communication (unless you use the new multiprocessing
> library in 2.6).
>
> One approach would be to run the socket code in blocking mode in a
> separate thread started by the (main program) GUI thread at program
> startup, and communicating results back via a Queue.Queue or similar to
> the GUI thread. That thread wakes itself up once every (say) 500 mS to
> check for updates from the socket side.
>
> You should see your CPU utilization go down then. The threading.thread
> library is actually much easier to use than you would think, though it's
> possible to get things wrong by assuming data sharing will work in ways
> it actually doesn't. But if you have the main thread pass a Queue to the
> networking thread, that should be a reliable means of communication.
>
> regards
>  Steve
> --
> Steve Holden        +1 571 484 6266   +1 800 494 3119
> Holden Web LLC              http://www.holdenweb.com/

Thankk you Steve, I have now a GUI and a threaded socket client
receiving data on its socket. I pass to it a queue object from the
GUI, but when it tries to push a value on the queue, the GUI does not
see any value. My last work with OOP is as far in time as the
beginning of Java, I'm surely missing something simple but very
important.
Anyway, the goal to have a responsive GUI and a functional socket has
been achieved, thanks again. If you have hints on the queue problem,
your help is welcome.

Bye
Max