comtypes

Introduction

• written by Thomas Heller ( http://python.net/crew/theller/ , ctypes package writer )
• official site : http://starship.python.net/crew/theller/comtypes/
• code repository: http://comtypes.svn.sourceforge.net/comtypes/

Pros and Cons

Pros

• pure python implementation
• direct use kernel32.dll, ole32.dll, oleaut32.dll, etc. no wrapping extension modules like pywin32 pythoncom.dll
• can use custom COM interface not based on IDispatch interface

Cons

• No ready-made data structures and constants for win32 sdk api. You have to implement.

Using Type Library for Early Bounding

comtypes.client.GetModule

• parse type library and create python module
  • location: C:\Python26\Lib\site-packages\comtypes-0.6.2-py2.6.egg\comtypes\gen
  • creates two .py files: one for typelib name and the other for typelib id
    • for example, Excel.py and _00020813_0000_0000_C000_000000000046_0_1_6.py
• usage
  • input com module name or (TypeLib Id, Major Version, Minor Version) tuple

>> tlb = comtypes.client.GetModule(("{00020813-0000-0000-C000-000000000046}", 1, 6))

or

>> tlb = comtypes.client.GetModule("C:\Program Files\Microsoft Office\Office12\EXCEL.EXE")

• module contents
  • IDispatch-based interface class
  • CoClass class
  • enumeration constants
• automatically executed by CreateObject command

Getting COM interface and object

• use 3 method
  • comtypes.client.CreateObject (most case)
  • comtypes.client.CoGetObject
  • comtypes.client.GetActiveObject

comtypes.client.CreateObject

• ole32.CoCreateInstance, ole32.CoCreateInstanceEx 의 wrapper

+ code example

>> xl = comtypes.client.CreateObject("Excel.Application")

# custom interface fetch
>> tlb = comtypes.client.GetModule(("{00020813-0000-0000-C000-000000000046}", 1, 6))
>> i_Application = comtypes.client.CreateObject("Excel.Application", None, None, tlb._Application)

comtypes.client.CoGetObject

• ole32.CoGetObject 의 wrapper
• use COM display name

comtypes.client.GetActiveObject

• oleaut32.GetActiveObject 의 wrapper
• get COM object already running

Event Processing

EventSink Class

• method name : EventIntefaceName_EventName
  • example: AppEvent_NewWorkbook

+ code example

import comtypes.client
from weakref import proxy
 
xl = comtypes.client.CreateObject("Excel.Application")
 
xl.Visible = True
 
class EventSink(object):
    def AppEvents_NewWorkbook(self, this, workbook):
        print "New Workbook", this, workbook
 
sink = EventSink()
sink.parent = proxy(xl)
connection = comtypes.client.GetEvents(xl, sink)
 
from PyQt4.QtGui import QApplication
app = QApplication([])
app.exec_()

ActiveX Control Hosting

• reference
  • http://svn.wxwidgets.org/viewvc/wx/wxPython/trunk/wx/lib/activex.py?content-type=text%2Fplain&view=co
  • http://svn.wxwidgets.org/viewvc/wx/wxPython/trunk/wx/lib/activexwrapper.py?content-type=text%2Fplain&view=co

+ code example

from win32api import * 
from win32gui import *
from win32con import *
from ctypes import byref, POINTER, windll
from comtypes import IUnknown, GUID
from comtypes.client import GetModule,  GetBestInterface, GetEvents
user32 = windll.user32
atl = windll.atl
 
#GetModule('shdocvw.dll')  # IWebBrowser2 and etc.
#from comtypes.gen import SHDocVw
 
# Hosting Window Creation
################################################################################
hInst = GetModuleHandle(None)
 
wc = WNDCLASS()
wc.hInstance = hInst
wc.lpszClassName = "AtlAxWinContainer"
wc.style = CS_VREDRAW | CS_HREDRAW;
wc.hCursor = LoadCursor(0, IDC_ARROW)
wc.hbrBackground = COLOR_WINDOW
wc.lpfnWndProc = {}
classAtom = RegisterClass(wc)
 
hwnd = CreateWindow(wc.lpszClassName, 
                    wc.lpszClassName,
                    WS_OVERLAPPEDWINDOW | WS_VISIBLE , 
                    CW_USEDEFAULT, 
                    CW_USEDEFAULT,
                    CW_USEDEFAULT, 
                    CW_USEDEFAULT,
                    0, 0, hInst, None)
ShowWindow(hwnd, SW_SHOW)
UpdateWindow(hwnd)
 
# ActiveX Control Hosting
################################################################################
atl.AtlAxWinInit() 
progID = 'Shell.Explorer.2'
hwnd2 = user32.CreateWindowExA(0, "AtlAxWin", progID,
                               WS_CHILD | WS_VISIBLE | WS_CLIPCHILDREN | WS_CLIPSIBLINGS,
                               0, 0, 0, 0, hwnd, None, hInst, 0)
 
Iwindow = POINTER(IUnknown)()
Icontrol = POINTER(IUnknown)()
Ievent = POINTER(IUnknown)()
 
#res = atl.AtlAxGetControl(hwnd2, byref(Icontrol))
res = atl.AtlAxCreateControlEx(progID, hwnd, None, 
                               byref(Iwindow),
                               byref(Icontrol),
                               byref(GUID()), 
                               Ievent) 
 
control = GetBestInterface(Icontrol)
control.Navigate2("http://www.google.com/")
 
# Event Sink Connection
################################################################################
class EventSink(object):
    def DWebBrowserEvents2_DownloadComplete(self, *args):
        print "DownloadComplete", args
 
sink = EventSink()
connection = GetEvents(control, sink)
print connection
 
# Event Loop
################################################################################
from PyQt4.QtGui import *
app = QApplication([])
app.exec_()

COM Server

+ code example

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