Python Programming On Win32

Chapter 5. Introduction to COM

In this chapter, we provide an introduction to using the Microsoft Component Object Model (COM) from Python. We will present enough introductory material so you can understand the key concepts and some simple examples that use Python and COM.

COM is a technique for using or publishing objects, regardless of the language they were implemented in. Any COM-aware environment uses a COM object in a consistent and reliable way; you need to know nothing about how the object is implemented.

COM has grown from humble beginnings. Its lineage can be traced through the Object Linking and Embedding (OLE) technology that first appeared in the Microsoft Windows 3.x family. The first version of Visual Basic included a technology known as Visual Basic Extensions, or VBXs. Microsoft started merging these technologies into OLE2, which was soon renamed COM. Since then, the Microsoft marketing machine has begun to refer to the technology as ActiveX, although COM remains the mnemonic of choice in the Windows development world. Recently, COM has been extended with the ability to distribute objects across a network, and these extensions are known as Distributed COM, or DCOM. Over time, the term DCOM will slowly vanish as the capabilities it offers are considered a standard part of COM. Microsoft is already hard at work on the next major revision of COM, currently known as COM+. Although COM+ isn’t discussed in this book, all the existing COM concepts will remain for the ...