Python COM Questions

[Dave Kirby]

Thanks for the fast response.  I will go the COM factory route, and brush up
on my C++ COM programming since I have not done any for years.

No doubt I will be back with more questions in the future.

Regards,

        Dave Kirby


"Mark Hammond" <mhammond at skippinet.com.au> wrote in message
news:3CCFFA71.4040106 at skippinet.com.au...
> Dave Kirby wrote:
> > The Background:
> > I am trying to write a GUI test automation system using the Microsoft
Active
> > Accessibility, which provides a COM interface for controlling the GUI
> > elements of another process. (see
http://msdn.microsoft.com/accessibility
> > for details).  The problem is that this has a DLL (oleacc.dll) with
factory
> > functions to generate COM wrappers for GUI elements, for example:
> >
> > STDAPI AccessibleObjectFromWindow(
> >   HWND hwnd,
> >   DWORD dwObjectID,
> >   REFIID riid,
> >   void** ppvObject
> > );
> >
> > this function creates a IAccessible COM object and writes its address
into
> > *ppvObject.  The problem is that I can't figure out how to call this
> > function (or any of the others) from Python.
> >
> > The Questions:
> > How do I get Python to access the factory functions?  I can see two
options:
> >
> > 1) write a C++ Python module, perhaps using SWIG, that exposes the
> > functions.  If I do this how do I convert the C++ created COM object
into
> > something that Python COM can use?  I presume that I need to generate a
> > Python wrapper round it, but I cant find out how to do that.
>
> There are functions exported from pythoncomxx.dll, but you will still be
> faced with the fact that Pythoncom doesn't understand the interface in
> question.
>
> You can add support for this interface manually, also using SWIG.  See
> the source code to the win32comext\exchange tree for an example.
>
> > 2) write a COM server that creates a COM factory object with these
functions
> > as methods.  This would be a more generic solution since it would be
usable
> > by any language that uses COM (and IMHO, what MS should have done in the
> > first place).   If I do this, I would like to be able to make the COM
server
> > InProc, so I dont have to go through the messyness of registering it
with
> > Windows.  So how do I call an InProc server from Python?
>
> InProc servers still need to be registered.  You call an InProc object
> like any other object; by using its CLSID.
>
> If IAccessible is described in a type library, another alternative would
> be to help getting support for arbitary interfaces into PythonCOM - but
> this is likely to be harder, as it is new ground.  We do have the "other
> side" implemented (ie, implementing interfaces) so adding support for
> calling them should be just as doable.
>
> Mark.
>