# A sample originally provided by Richard Bell, and modified by Mark Hammond.
# This sample demonstrates how to use COM events in a free-threaded world.
# In this world, there is no need to marshall calls across threads, so
# no message loops are needed at all. This means regular cross-thread
# sychronization can be used. In this sample we just wait on win32 event
# objects.
# See also ieEventsApartmentThreaded.py for how to do this in an
# aparment-threaded world, where thread-marshalling complicates things.
# NOTE: This example uses Internet Explorer, but it should not be considerd
# a "best-practices" for writing against IE events, but for working with
# events in general. For example:
# * The first OnDocumentComplete event is not a reliable indicator that the
# URL has completed loading
# * As we are demonstrating the most efficient way of handling events, when
# running this sample you will see an IE Windows briefly appear, but
# vanish without ever being repainted.
import sys
sys.coinit_flags=0 # specify free threading
import os
import win32api
import win32event
import win32com.client
import pythoncom
import time
# The print statements indicate that COM has actually started another thread
# and will deliver the events to that thread (ie, the events do not actually
# fire on our main thread.
class ExplorerEvents:
def __init__(self):
# We reuse this event for all events.
self.event = win32event.CreateEvent(None, 0, 0, None)
def OnDocumentComplete(self,
pDisp=pythoncom.Empty,
URL=pythoncom.Empty):
#
# Caution: Since the main thread and events thread(s) are different
# it may be necessary to serialize access to shared data. Because
# this is a simple test case, that is not required here. Your
# situation may be different. Caveat programmer.
#
thread = win32api.GetCurrentThreadId()
print "OnDocumentComplete event processed on thread %d"%thread
# Set the event our main thread is waiting on.
win32event.SetEvent(self.event)
def OnQuit(self):
thread = win32api.GetCurrentThreadId()
print "OnQuit event processed on thread %d"%thread
win32event.SetEvent(self.event)
def TestExplorerEvents():
iexplore = win32com.client.DispatchWithEvents(
"InternetExplorer.Application", ExplorerEvents)
thread = win32api.GetCurrentThreadId()
print 'TestExplorerEvents created IE object on thread %d'%thread
iexplore.Visible = 1
try:
iexplore.Navigate(win32api.GetFullPathName('..\\readme.htm'))
except pythoncom.com_error, details:
print "Warning - could not open the test HTML file", details
# In this free-threaded example, we can simply wait until an event has
# been set - we will give it 2 seconds before giving up.
rc = win32event.WaitForSingleObject(iexplore.event, 2000)
if rc != win32event.WAIT_OBJECT_0:
print "Document load event FAILED to fire!!!"
iexplore.Quit()
# Now we can do the same thing to wait for exit!
# Although Quit generates events, in this free-threaded world we
# do *not* need to run any message pumps.
rc = win32event.WaitForSingleObject(iexplore.event, 2000)
if rc != win32event.WAIT_OBJECT_0:
print "OnQuit event FAILED to fire!!!"
iexplore = None
print "Finished the IE event sample!"
if __name__=='__main__':
TestExplorerEvents()
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