Accessing unregistered COM objects from python via a registered TLB

Question

I have three pieces of code that i\'m working with at the moment:

• A closed source application (Main.exe)
• A closed source VB COM object implemented as

Answer 1

Here is a method I devised to load a COM object from a DLL. It was based on a lot of reading about COM, etc. I'm not 100% sure about the last lines, specifically d=. I think that only works if IID_Dispatch is passed in (which you can see if the default param).

In addition, I believe this code leaks - for one, the DLL is never unloaded (use ctypes.windll.kernel32.FreeLibraryW) and I believe the COM ref counts for the initial class factory are off by one, and thus never get released. But still, this works for my application.

import pythoncom
import win32com.client
def CreateInstanceFromDll(dll, clsid_class, iid_interface=pythoncom.IID_IDispatch, pUnkOuter=None, dwClsContext=pythoncom.CLSCTX_SERVER):
    from uuid import UUID
    from ctypes import OleDLL, c_long, byref
    e = OleDLL(dll)
    clsid_class = UUID(clsid_class).bytes_le
    iclassfactory = UUID(str(pythoncom.IID_IClassFactory)).bytes_le
    com_classfactory = c_long(0)
    hr = e.DllGetClassObject(clsid_class, iclassfactory, byref(com_classfactory))
    MyFactory = pythoncom.ObjectFromAddress(com_classfactory.value, pythoncom.IID_IClassFactory)
    i = MyFactory.CreateInstance(pUnkOuter, iid_interface)
    d = win32com.client.__WrapDispatch(i)
    return d