[python-win32] Win32com events, multithreading, and re-entrancy

[Moore, Paul]

I'm getting in a muddle trying to understand what's going on here...

from win32com.client import DispatchWithEvents, constants
import sys

# sys.coinit_flags =3D 0
import pythoncom

finished =3D 0

class ADOEvents:
    def OnWillConnect(self, str, user, pw, opt, sts, cn):
        # Must have this event, as if it is not handled, ADO assumes the
        # operation is cancelled, and raises an error (Operation =
cancelled
        # by the user)
        pass
    def OnConnectComplete(self, error, status, connection):
        # print "Connected to", connection.Properties("Data Source")
        global finished
        finished =3D 1

c =3D DispatchWithEvents("ADODB.Connection", ADOEvents)
str =3D "Provider=3Dmsdaora;Data Source=3DOEM.UKRUR053"
c.Open(str, "system", "manager", constants.adAsyncConnect)

while not finished:
    pythoncom.PumpWaitingMessages()
    print ".",

This is an ADO program, trying to catch the ADO connection events. The =
program works fine, *as long as* the print statement in =
OnConnectComplete is commented out. Any attempt to access the connection =
object from within the event handler causes Python to jump back into the =
main busy wait loop, pumping messages and printing dots.

I assume that this is somehow related to the internal multithreading and =
serialisation that goes on in COM, but I don't know enough about that to =
understand it. Trying to make the code free-threaded (assigning to =
sys.coinit_flags - BTW, there's a bug in the documentation for =
pythoncom.CoInitializeEx, which gives 2 variations on this name) didn't =
seem to help.

How do I do this? Is there any sample code which shows how to do this? =
Mark Hammond's book doesn't cover ADO events, and I've read the =
threading appendix and am still no wiser...

Actually, on a more general note, is there any sample win32com code =
around anywhere? The samples and tests included with the package are =
useful, but they only go so far. Also some of them are out of date (I =
was looking at the universal gateway stuff yesterday, and testuniv.py =
doesn't even load, as "import univgw" no longer works :-()

Thanks for any suggestions,
Paul.