IMessageFilter
A python package implements interface IMessageFilter for COM.
The main purpose is to fix 'Application is Busy' and 'Call was Rejected By Callee' errors in a WINDOWS COM/COM+ client.
Here is a workaround
https://docs.microsoft.com/en-us/previous-versions/ms228772(v=vs.140)
But it's written by C#, this package offers both C and Python versions.
Usage
Install it:
pip install imessagefilter
Import CMessageFilter from imessagefilter
Call static method register at the beginning of automation
Call static method revoke at the end of work
Here it's an example:
from comtypes.client import CreateObject
from imessagefilter import CMessageFilter
def iter_excel_sheets(filename):
CMessageFilter.register()
aobj = CreateObject('Excel.Application', dynamic=True)
aobj.Workbooks.Open(filename)
for sheet in aobj.ActiveWorkbook.Worksheets:
print('Processing %s' % sheet.Name)
CMessageFilter.revoke()
Note
The interface IMessageFilter only works in single-threaded apartments, it will not be called in the multithreaded apartments.
Refer to https://docs.microsoft.com/en-us/windows/desktop/com/choosing-the-threading-model
Build msgfilter.dll
By visual studio command line:
cl /LD msgfilter.c ole32.lib
By mingw32 in cygwin:
i686-pc-mingw32-gcc -shared -o msgfilter.dll msgfilter.c -lole32 -luuid
There are 2 export functions, they can be used in any c file.
Here it's an exmaple:
#include <stdio.h>
#include <objbase.h>
extern void register_message_filter();
extern void revoke_message_filter();
int main(int argc, char* argv[])
{
HRESULT ret;
ret = CoInitializeEx(0, COINIT_APARTMENTTHREADED);
register_message_filter();
// do something for automation
revoke_message_filter();
CoUninitialize();
return 0;
}
Change Logs
0.2.1
- Search msgfilter.dll in the current path first
0.1.3
- Fix no long description in package information
0.1.2
- Fix typos