A few months ago I posted asking for some advice on ways to extend classes provided by com objects.
Primarily I was keen to make a com library that I work with a lot (Notes/Domino if anyone's interested) nicer and more pythonic to use. I've spent a good few hours bashing away and have found two ways which appear to work with my simplistic test suite. However I'm not particularly comfortable with either of them (the black magic I'm using is all a bit new to me). Consequently if anyone has time to have a look at my solutions I'd be very grateful. Attempt #1 (code at http://www2.crummock.com/comwrapper.py): Based on what Tim Golden called a "Delegation model", involved holding an internal copy of my com class and by implementing getattr/setattr calling the com object when necessary. This turned out a fair bit more complicated than I originally expected as lots of the com objects methods returned other com objects from the same library. I wanted these returned com objects to also be automatically wrapped in my extension classes to save having to constantly wrap in my client code. To do this I ended up with some very convoluted code that intercepted all my com method calls to see if they returned a com object for which I had a corresponding wrapper class and if so, wrap it. Of course I then had to check all tuples returned to see if they also contained candidates for wrapping. I got this working (well enough that it passed my far-from-comprehensive test-suite) but I wasn't convinced by it: the complexity of my wrapping system is bound to contain some subtle bugs and it also introduced a significant performance overhead (about 15% runtime overhead from some rough tests). Attempt #2: This very simple, alternative method then occured to me: #My custom classes class IDocument: ... class IDatabase: ... class IDocumentCollection: ... from win32com.client.gencache import GetModuleForProgID module = GetModuleForProgID('Lotus.NotesSession') implementedChildClasses = (IDocument,IDatabase,IDocumentCollection) for klass in implementedChildClasses: #find parent class of same name parentclass = getattr(module,klass.__name__) parentclass.__dict__.update(klass.__dict__) I just put this code at the bottom of my module and it automagically adds all my methods & attributes from classes listed in "implementedChildClasses" to the com class (at the expense of needing to run makepy on the com library, of course). The beauty of this is that I dont have to worry about wrapping the results of any functions as I'm always dealing with the real com class, just with some extra methods added. It is also a more efficient - a small overhead when loading the module but a lot quicker when using it. Unfortunately, it does feel like a big hack and I'm not convinced it's a sensible thing to do? So, I dont actually have any real problems as such I'm just looking for advice/comments from anyone who is more familiar with all these magical techniques. -ross _______________________________________________ Python-win32 mailing list Python-win32@python.org http://mail.python.org/mailman/listinfo/python-win32
