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Recipe 580707 revision 2 

# Based on this file: 
#   https://github.com/pallets/werkzeug/blob/master/werkzeug/_reloader.py


import time, os, sys, subprocess

PY2 = sys.version_info[0] == 2

class ReloaderLoop(object):

    def restart_with_reloader(self):
        """Spawn a new Python interpreter with the same arguments as this one,
        but running the reloader thread.
        """
        while 1:
            print("starting Tkinter application...")

            args = [sys.executable] + sys.argv
            new_environ = os.environ.copy()
            new_environ['TKINTER_RUN_MAIN'] = 'true'

            # a weird bug on windows. sometimes unicode strings end up in the
            # environment and subprocess.call does not like this, encode them
            # to latin1 and continue.
            if os.name == 'nt' and PY2:
                for key, value in iteritems(new_environ):
                    if isinstance(value, text_type):
                        new_environ[key] = value.encode('iso-8859-1')

            exit_code = subprocess.call(args, env=new_environ,
                                        close_fds=False)
            if exit_code != 3:
                return exit_code

    def trigger_reload(self):
        self.log_reload()
        sys.exit(3)

    def log_reload(self):
        print("reloading...")

def run_with_reloader(App, *hotkeys):
    """Run the given function in an independent python interpreter."""
    import signal
    signal.signal(signal.SIGTERM, lambda *args: sys.exit(0))
    reloader = ReloaderLoop()
    try:
        if os.environ.get('TKINTER_RUN_MAIN') == 'true':
            app = App()

            for hotkey in hotkeys:
                app.bind_all(hotkey, lambda event: reloader.trigger_reload())
            app.mainloop()
        else:
            sys.exit(reloader.restart_with_reloader())
    except KeyboardInterrupt:
        pass

Diff to Previous Revision

--- revision 1 2016-10-22 13:35:16
+++ revision 2 2016-10-24 16:35:24
@@ -1,10 +1,10 @@
-#### Realoader code ###########
 # Based on this file: 
 #   https://github.com/pallets/werkzeug/blob/master/werkzeug/_reloader.py
 
 
 import time, os, sys, subprocess
 
+PY2 = sys.version_info[0] == 2
 
 class ReloaderLoop(object):
 
@@ -39,13 +39,15 @@
     def log_reload(self):
         print("reloading...")
 
-def run_with_reloader(app, *hotkeys):
+def run_with_reloader(App, *hotkeys):
     """Run the given function in an independent python interpreter."""
     import signal
     signal.signal(signal.SIGTERM, lambda *args: sys.exit(0))
     reloader = ReloaderLoop()
     try:
         if os.environ.get('TKINTER_RUN_MAIN') == 'true':
+            app = App()
+
             for hotkey in hotkeys:
                 app.bind_all(hotkey, lambda event: reloader.trigger_reload())
             app.mainloop()
@@ -53,23 +55,3 @@
             sys.exit(reloader.restart_with_reloader())
     except KeyboardInterrupt:
         pass
-
-#####################################
-#
-# Example of usage
-#
-
-try:
-    from Tkinter import Tk, Label
-except ImportError:
-    from tkinter import Tk, Label
-
-class App(Tk):
-    def __init__(self):
-        Tk.__init__(self)
-        self.label = Label(self, text="Press Control+r to reload the application")
-        self.label.pack()
-        
-
-# Press Controol-R or Control-r to reload application
-run_with_reloader(App(), "<Control-R>", "<Control-r>")

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