My python application stops responding whenever I do anything "wx" a few times...whether that be clicking buttons, menus, inside the text area, etc.
This seems to be a problem with my use of windows hooks elsewhere in the program. When the two are used together, things go bad.
While the example below might not make much sense outside the context of the real application, it is what I came up with as a minimal example. I took everything out I could in order to try to diagnose the problem with minimal extra complexities.
It really seems like the second windows message pump called from the worker thread is the factor that makes it happen. If I comment that out, the app doesn't hang...or do anything useful...Hooks requires a pump, and I can't put it on my UI thread or it will the hooks will timeout, which led me to this POC in the first place...
If you run this and click the mouse a dozen times or so, you will notice the text blocks get garbled and then the app just hangs. Does anyone have any insight as to why?
I am using
- python 2.7.16 32 bit
- pyHook 1.5.1
- wxPython 3.0.2.0 32bit for python 2.7
(update) I've also tried with the same results
- python 2.7.16 32 bit
- pyHook 1.5.1
- wxPython 4.0.6 32 bit for python 2.7
We use these in the real application, because the my higher ups want to continue to support Windows XP (A whole different conversation)
main.py
import wx
from twisted.internet import wxreactor
from windows_hooks import WindowsHooksWrapper
from main_window import MainWindow
def main():
hook_wrapper = WindowsHooksWrapper()
hook_wrapper.start()
app = wx.App(False)
frame = MainWindow(None, 'Hooks Testing', hook_wrapper)
from twisted.internet import reactor
reactor.registerWxApp(app)
reactor.run()
hook_wrapper.stop()
if __name__ == "__main__":
wxreactor.install()
main()
windows_hooks.py
import pyHook
import threading
import pythoncom
class WindowsHooksWrapper(object):
def __init__(self):
self.hook_manager = None
self.started = False
self.thread = threading.Thread(target=self.thread_proc)
self.window_to_publish_to = None
print "HookWrapper created on Id {}".format(threading.current_thread().ident)
def __del__(self):
self.stop()
def start(self):
if self.started:
self.stop()
self.started = True
self.thread.start()
def stop(self):
if not self.started:
return
self.started = False
self.thread.join()
def on_mouse_event(self, event):
"""
Called back from pyHooks library on a mouse event
:param event: event passed from pyHooks
:return: True if we are to pass the event on to other hooks and the process it was intended
for. False to consume the event.
"""
if self.window_to_publish_to:
from twisted.internet import reactor
reactor.callFromThread(self.window_to_publish_to.print_to_text_box, event)
return True
def thread_proc(self):
print "Thread started with Id {}".format(threading.current_thread().ident)
# Evidently, the hook must be registered on the same thread with the windows msg pump or
# it will not work and no indication of error is seen
# Also note that for exception safety, when the hook manager goes out of scope, the
# documentation says that it unregisters all outstanding hooks
self.hook_manager = pyHook.HookManager()
self.hook_manager.MouseAll = self.on_mouse_event
self.hook_manager.HookMouse()
while self.started:
pythoncom.PumpMessages()
print "Thread exiting..."
self.hook_manager.UnhookMouse()
self.hook_manager = None
main_window.py
import threading
import wx
class MainWindow(wx.Frame):
def __init__(self, parent, title, hook_manager):
wx.Frame.__init__(self, parent, title=title, size=(800, 600))
self.hook_manager = hook_manager
self.CreateStatusBar()
menu_file = wx.Menu()
menu_item_exit = menu_file.Append(wx.ID_EXIT, "E&xit", " Terminate the program")
menu_help = wx.Menu()
menu_item_about = menu_help.Append(wx.ID_ABOUT, "&About", " Information about this program")
menu_bar = wx.MenuBar()
menu_bar.Append(menu_file, "&File")
menu_bar.Append(menu_help, "&Help")
self.SetMenuBar(menu_bar)
self.panel = MainPanel(self, hook_manager)
self.Bind(wx.EVT_MENU, self.on_about, menu_item_about)
self.Bind(wx.EVT_MENU, self.on_exit, menu_item_exit)
self.Show(True)
def on_about(self, e):
dlg = wx.MessageDialog(self, "A window to test Windows Hooks", "About Test Windows Hooks",
wx.OK)
dlg.ShowModal()
dlg.Destroy()
def on_exit(self, e):
self.Close(True)
class MainPanel(wx.Panel):
def __init__(self, parent, hook_manager):
self.hook_manager = hook_manager
hook_manager.window_to_publish_to = self
self.consuming = False
wx.Panel.__init__(self, parent)
self.textbox = wx.TextCtrl(self, style=wx.TE_MULTILINE | wx.TE_READONLY)
self.horizontal = wx.BoxSizer()
self.horizontal.Add(self.textbox, proportion=1, flag=wx.EXPAND)
self.sizer_vertical = wx.BoxSizer(wx.VERTICAL)
self.sizer_vertical.Add(self.horizontal, proportion=1, flag=wx.EXPAND)
self.SetSizerAndFit(self.sizer_vertical)
self.called_back_count = 0
def print_to_text_box(self, event):
self.called_back_count += 1
print "Printing message {} on Thread with Id {}".format(self.called_back_count,
threading.current_thread().ident)
self.textbox.AppendText('MessageName: {}\n'.format(event.MessageName))
self.textbox.AppendText('Message: {}\n'.format(event.Message))
self.textbox.AppendText('Time: {}\n'.format(event.Time))
self.textbox.AppendText('Window: {}\n'.format(event.Window))
self.textbox.AppendText('WindowName: {}\n'.format(event.WindowName))
self.textbox.AppendText('Position: {}\n'.format(event.Position))
self.textbox.AppendText('Wheel: {}\n'.format(event.Wheel))
self.textbox.AppendText('Injected: {}\n'.format(event.Injected))
self.textbox.AppendText('---\n')
I've also tried a version without Twisted and used wxPostEvent with a custom event instead, but we were suspecting that might be the problem, so I changed it to use twisted and it's still no good.
I'll post an edited listing with that in a bit.
