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POgobject and subprocess.Popen to communicate in a GTK GUI
 

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    <p>I am trying to use a gobject to allow communication between a Popen process and a GTK GUI.</p> <p>Inspired by this: <a href="https://pygabriel.wordpress.com/2009/07/27/redirecting-the-stdout-on-a-gtk-textview/#comment-156" rel="nofollow">https://pygabriel.wordpress.com/2009/07/27/redirecting-the-stdout-on-a-gtk-textview/#comment-156</a></p> <p>I implemented something similar to this:</p> <p><a href="http://hartree.altervista.org/files/command-textview.py" rel="nofollow">http://hartree.altervista.org/files/command-textview.py</a></p> <p>but I noticed that the gobject uses lots of CPU cycle even once the Popen process is terminated. Just run the scrip above and watch the Ubuntu System Monitor.</p> <p>After some work with "pty" I came up with this:</p> <pre><code>import gtk,pygtk import subprocess import gobject import pty, os, time class CommandTextView(gtk.TextView): def __init__(self): super(CommandTextView,self).__init__() self.master, self.slave = pty.openpty() gobject.io_add_watch(os.fdopen(self.master), gobject.IO_IN, self.write_to_buffer) self.proc = None def run(self, w, cmd): if self.proc == None or self.proc.poll() != None: # poll()=None means still running self.proc = subprocess.Popen(cmd.split(), shell=True, stdout=self.slave, stderr=self.slave) def stop(self,w): if type(self.proc) is subprocess.Popen: self.proc.kill() while self.proc.poll() == None: time.sleep(0.1) self.proc = None def write_to_buffer(self, fd, condition): if condition == gobject.IO_IN: char = fd.readline() print 'adding:',char buf = self.get_buffer() buf.insert_at_cursor(char) return True else: return False def test(): win=gtk.Window() vbox = gtk.VBox(False, 0) win.set_size_request(300,300) win.connect('delete-event',lambda w,e : gtk.main_quit()) ctv=CommandTextView() bt1 = gtk.Button('Run') bt2 = gtk.Button('Stop') vbox.pack_start(ctv) vbox.pack_end(bt2,False,False) vbox.pack_end(bt1,False,False) win.add(vbox) bt1.connect("clicked", ctv.run, 'ls -la') bt2.connect("clicked", ctv.stop) win.show_all() gtk.main() if __name__=='__main__': test() </code></pre> <p>The questions I have are:</p> <ul> <li><p>is pty a good idea? Can it be used for Windows too?</p></li> <li><p>is it possible to avoid using pty and just use stdout and not have the high CPU usage problem?</p></li> <li><p>if you run this scrip the first time it seems to buffer the txt output and give an incomplete output.</p></li> </ul> <p>Thank you for the help</p>
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