Good examples and best practices for writing Python wrappers around C APIs

Question

I have an internal API, written in C, which I'd like to write a Python wrapper around it. The API is well structured: it has a few data structs and functions for each kind of struct, like this:

struct XYZ;

MYAPI_XyzDoBuzz(XYZ* xyz, int other, int parameters);
MYAPI_XyzDoFizz(XYZ* xyz, int other, double funky, int parameters);

I was thinking into creating a myapi module and a class Xyz inside this module with methods like do_buzz and do_fizz. Each method would call it's corresponding function in the dynamic library, probably through ctypes (maybe the module keeping a global variable with the result from the ctypes.CDLL call).

Is my proposed structure a good way to expose this API to Python? Are there guidelines and best practices examples for wrapping C dlls for Python?

Answer 1

Have you tried using swig to generate your wrapper? The projects page will give you many examples of swig in action to see what sort of code it produces.

Answer 2

The original doc on extending Python might be worth a look. It's a bit old-school with a lot of details to track, but if you take the time to plod through it, you'll understand things thoroughly. Mapping structs to Python objects works as you described it, and is covered in detail in section 2.