Tilting at Windmills with ctypes and cygwinreg

Tilting at Windmills with ctypes and cygwinreg Simon Law simon@akoha.com

def introduction():

social reality game

def problem():

website

testing

click wait look

laborious

boring

automated testing

def test_browser():

getwindmill.com

one script

all browsers

from windmill.authoring import * def setup_module(module): client = WindmillTestClient(__name__) client.click(id=u'home') client.waits.forPageLoad(timeout=u'60000') client.asserts.assertNode(id='LoginPage')

semi-automated testing

def continuous_integration():

test automatically

buildbot.net

~/akoha$ make check

C:>make check 'make' is not recognized as an internal or external command, operable program or batch file.

cygwin.com

~/akoha$ make check

Traceback (most recent call last): ... ImportError: No module named _winreg

def windows_registry():

proxy settings

import _winreg

import winreg

32.3. winreg Windows registry access Platforms: Windows

3 choices

give up

recompile Python

cygwinreg

like hurting myself

def call_system_libraries():

import ctypes

foreign function interface

call functions

shared libraries

libiberty.so

libgcc.dynlib

advapi32.dll

>>> from ctypes import cdll

>>> cdll.advapi32 <CDLL 'advapi32', ... at ...>

>>> cdll.advapi32.RegCloseKey <_FuncPtr object at 0x...>

>>> a = cdll.advapi32 >>> RegCloseKey = a.RegCloseKey >>> RegCloseKey(0) 6

no introspection

>>> RegCloseKey(0) 6 >>> RegCloseKey() 6

return value

function arguments

from ctypes import cdll from ctypes import c_long, c_ulong # WINADVAPI LONG WINAPI RegCloseKey(HKEY); RegCloseKey = cdll.advapi32.RegCloseKey RegCloseKey.restype = c_long RegCloseKey.argtypes = [c_ulong]

from ctypes import cdll from ctypes import c_long, c_ulong LONG = c_long HANDLE = c_ulong # in header files: void * HKEY = HANDLE # WINADVAPI LONG WINAPI RegCloseKey(HKEY); RegCloseKey = cdll.advapi32.RegCloseKey RegCloseKey.restype = LONG RegCloseKey.argtypes = [HKEY]

>>> RegCloseKey(0) 6 >>> RegCloseKey() Traceback (most recent call last): ... TypeError: this function takes at least 1 argument (0 given)

not Pythonic

PyHKEY.Close() Closes the underlying Windows handle.

class PyHKEY(object): def __init__(self, hkey): self.hkey = hkey def Close(self): if RegCloseKey(self.hkey) != 0: raise WindowsError() self.hkey = 0 class WindowsError(OSError): ...

class PyHKEY(object): def __init__(self, hkey): self.hkey = hkey def Close(self): RegCloseKey(self.hkey) raise WindowsError() self.hkey = 0 class WindowsError(OSError): ...

class PyHKEY(object): def __init__(self, hkey): self.hkey = hkey def Close(self): if RegCloseKey(self.hkey) != 0: raise WindowsError() self.hkey = 0 class WindowsError(OSError): ...

>>> from cygwinreg import PyHKEY >>> hkey = PyHKEY(0) >>> hkey.Close()

RegDeleteKeyW = cdll.advapi32.RegDeleteKeyW RegDeleteKeyW.restype = LONG RegDeleteKeyW.argtypes = [HKEY, LPCWSTR]

def DeleteKey(key, sub_key): from cygwinreg.w32api import RegDeleteKeyW wincall(RegDeleteKeyW(PyHKEY.make(key), sub_key))

hours later

>>> try: ... import winreg ... except ImportError: ... import cygwinreg as winreg

def tradeoffs():

Python only

no compilation

slower

no parsing

simple

not automatic

standard

portable

good enough

def conclusion():

~/akoha$ make check

continuous integration

browser tests

pypi.python.org/pypi/cygwinreg

no compilation

no installation

no :'-(

cygwinreg pypi.python.org/pypi/cygwinreg PSF License this presentation: Attribution-Share Alike 3.0

Tilting at Windmills with ctypes and cygwinreg

by Simon Law on Oct 01, 2009

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Tilting at Windmills with ctypes and cygwinreg — Webinar Transcript