wrapdll

Allows using python annotaions to wrap dlls using ctypes.

Usefull for when you have to use a dll in your python project and you want to make the dll function more pythonic.

Example

The best way to understand this package is with an example. In this example we wrap one of the exported functions of python3.dll from the installation directory

import sys
from ctypes import *
from pathlib import Path
from wrapdll import BaseDllWrapper, wrapdll 

class PythonAPI(BaseDllWrapper):
    """
    A wrapper to ctypes.pythonapi
    """

    def __init__(self):
        api = str(Path(sys.exec_prefix, 'python3.dll'))
        super().__init__(api)

    @wrapdll
    def PyBytes_FromStringAndSize(self, v: c_char_p, len: c_size_t) -> py_object:
        """
        Return a new bytes object with a copy of the string v as value and length len on success, and NULL on failure.
        If v is NULL, the contents of the bytes object are uninitialized.
        """
        pass

The args and return type are automatically set from the annotations. In addition, the function gets a better signature and doc when you run help on it:

In [2]: api = PythonAPI()

In [3]: help(api.PyBytes_FromStringAndSize)
Help on method PyBytes_FromStringAndSize in module __main__:

PyBytes_FromStringAndSize(v: ctypes.c_char_p, len: ctypes.c_ulong) -> ctypes.py_object method of __main__.PythonAPI instance
    Return a new bytes object with a copy of the string v as value and length len on success, and NULL on failure.
    If v is NULL, the contents of the bytes object are uninitialized.

Features

• BaseDllWrapper class and wrapdll decorator to create wraped dll classes
• errcheck, allowed_values and forbidden_values decorators to automatically raise an exception on invalid values. (Look at tests\wraped_kernel32.py for example)
• RCEnum to create IntEnums with a built-in error message. Works magic when used as a return type in conjuncture with the allowed/forbidden decorators to automatically raise a comprehensive exception.

Installation

pip install wrapdll