99 lines
3.6 KiB
Python
99 lines
3.6 KiB
Python
# A sample originally provided by Richard Bell, and modified by Mark Hammond.
|
|
|
|
# This sample demonstrates how to use COM events in an aparment-threaded
|
|
# world. In this world, COM itself ensures that all calls to and events
|
|
# from an object happen on the same thread that created the object, even
|
|
# if they originated from different threads. For this cross-thread
|
|
# marshalling to work, this main thread *must* run a "message-loop" (ie,
|
|
# a loop fetching and dispatching Windows messages). Without such message
|
|
# processing, dead-locks can occur.
|
|
|
|
# See also eventsFreeThreaded.py for how to do this in a free-threaded
|
|
# world where these marshalling considerations do not exist.
|
|
|
|
# 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 time
|
|
|
|
# sys.coinit_flags not set, so pythoncom initializes apartment-threaded.
|
|
import pythoncom
|
|
import win32api
|
|
import win32com.client
|
|
import win32event
|
|
|
|
|
|
class ExplorerEvents:
|
|
def __init__(self):
|
|
self.event = win32event.CreateEvent(None, 0, 0, None)
|
|
|
|
def OnDocumentComplete(self, pDisp=pythoncom.Empty, URL=pythoncom.Empty):
|
|
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 WaitWhileProcessingMessages(event, timeout=2):
|
|
start = time.perf_counter()
|
|
while True:
|
|
# Wake 4 times a second - we can't just specify the
|
|
# full timeout here, as then it would reset for every
|
|
# message we process.
|
|
rc = win32event.MsgWaitForMultipleObjects(
|
|
(event,), 0, 250, win32event.QS_ALLEVENTS
|
|
)
|
|
if rc == win32event.WAIT_OBJECT_0:
|
|
# event signalled - stop now!
|
|
return True
|
|
if (time.perf_counter() - start) > timeout:
|
|
# Timeout expired.
|
|
return False
|
|
# must be a message.
|
|
pythoncom.PumpWaitingMessages()
|
|
|
|
|
|
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.html"))
|
|
except pythoncom.com_error as details:
|
|
print("Warning - could not open the test HTML file", details)
|
|
|
|
# Wait for the event to be signalled while pumping messages.
|
|
if not WaitWhileProcessingMessages(iexplore.event):
|
|
print("Document load event FAILED to fire!!!")
|
|
|
|
iexplore.Quit()
|
|
#
|
|
# Give IE a chance to shutdown, else it can get upset on fast machines.
|
|
# Note, Quit generates events. Although this test does NOT catch them
|
|
# it is NECESSARY to pump messages here instead of a sleep so that the Quit
|
|
# happens properly!
|
|
if not WaitWhileProcessingMessages(iexplore.event):
|
|
print("OnQuit event FAILED to fire!!!")
|
|
|
|
iexplore = None
|
|
|
|
|
|
if __name__ == "__main__":
|
|
TestExplorerEvents()
|