[pywin32-bugs] [ pywin32-Bugs-3525912 ] InvokeTypes error using win32com v2.17

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Bugs item #3525912, was opened at 2012-05-11 10:37
Message generated for change (Comment added) made by mhammond
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Category: win32
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Mike Fox (mike_fox)
Assigned to: Nobody/Anonymous (nobody)
Summary: InvokeTypes error using win32com v2.17

Initial Comment:
I think we have found a bug in win32com 2.17.  We are using it with Python 2.7.2.  We are calling a proprietary DLL named PATE, which provides APIs to a database named Enovia from the Dassault corporation.  The Enovia client is linked to a CAD program named CATIA so we must conjure objects of both CATIA and Enovia as shown in the code snippet below.  The strApplicationID is a password administered by my company and has nothing to do with the PATE DLL itself.  Rather, PATE should pass the strApplicationID to the Enovia server, which should authenticate the session.
====================================================================
import win32com.client, win32com.client.gencache, win32com.client.selecttlb
strPATECLSID = '{9BB3CB79-7098-47D0-83A2-F8F56D236DC8}'
strPATEclassCLSID = '{9A1F3C8E-46B7-4CFA-A820-E4256ECD53B5}'

self.objCATIA = win32com.client.GetActiveObject('CATIA.Application')
win32com.client.gencache.EnsureModule(strPATECLSID, 0, 0, 0)
self.objBase= win32com.client.gencache.GetClassForCLSID(strPATEclassCLSID)
self.__objPATECOM = self.objBase(self.objCATIA)
strApplicationID = <secret> 
try:
    self.__objPATECOM.SetApplicationID(strApplicationID)
except (pywintypes.com_error), _e:
    print "Connection error: %s" %(_e)
    return False
====================================================================
When we use win32com 2.16 the code above works fine but when we use win32com 2.17 it throws the error message shown below.

   File testKBE_PATECAKE.py, line 367 in ConnectToENOVIA
     self.__objPATECOM.SetApplicationID(strApplicationID)
   File "C:\Python27\lib\site-packages\win32com\gen_py\9BB3CB79 -7098-47D0-83A2-F8
F56D236DC8x0x0x0.py", line 457 in SetApplicationID
     return self._oleobj_.InvokeTypes(1610940417, LCID, 1, (24, 0), ((16396, 1),)
, iAID
   File "C:\Python27\lib\site-packages\win32com\client\dynamic.py", line 516 in 
__getattr__
     raise AttributeError("%s.%s" % (self._username_, attr))
   AttributeEror: CATIA.Application.InvokeTypes

----------------------------------------------------------------------

>Comment By: Mark Hammond (mhammond)
Date: 2012-05-30 16:42

Message:
It looks like the genpy idea I had was wrong - the objects are the same in
both examples.

What should happen is that the line:

  self.__objPATECOM = self.objBase(self.objCATIA)

end up calling DispatchBaseClass.__init__ which is in
win32com\client\__init__.py.  What *should* happen, and appears to be
happening in 216 is it should enter the branch:

		elif isinstance(oobj, DispatchBaseClass):
			try:
				oobj = oobj._oleobj_.QueryInterface(self.CLSID,
pythoncom.IID_IDispatch) # Must be a valid COM instance
			except pythoncom.com_error, details:
				import winerror
				# Some stupid objects fail here, even tho it is _already_
IDispatch!!??
				# Eg, Lotus notes.
				# So just let it use the existing object if E_NOINTERFACE
				if details.hresult != winerror.E_NOINTERFACE:
					raise
				oobj = oobj._oleobj_

In the working case it just does the QI so oobj ends up as a "raw"
IDispatch.  In your failing 217 scenario, it seems to be either not hitting
that first condition at all, or enters that block but hits the "except
pythoncom.com_error" block.

You might want to instrument that code with prints to try and (a) confirm
I'm correct in the working case and (b) work out how it fails in the
failing case (ie, whether the 'if' statement simply isn't entered at all or
it hits the exception).

----------------------------------------------------------------------

Comment By: Mike Fox (mike_fox)
Date: 2012-05-30 11:11

Message:
Sorry for the delay.  I added print statements after lines 4, 6, and 7 (in
the code shown in my original post).  With version 2.16
(pywin32-216.win-amd64-py2.7) I get the following correct output:
    self.objCATIA= <COMObject CATIA.Application>
    self.objBase=
win32com.gen_py.9BB3CB79-7098-47D0-83A2-F8F56D236DC8x0x0x0.PATECOM
    self.__objPATECOM= <win32com.gen_py.CATIA V5
BOEPATEAutomationInterfaces Object 
                       Library.PATECOM instance at 0x44540104>

Then I ran the same sript with version 2.17 (pywin32-217.win-amd64-py2.7)
and got the following:
    self.objCATIA= <COMObject CATIA.Application>
    self.objBase=
win32com.gen_py.9BB3CB79-7098-47D0-83A2-F8F56D236DC8x0x0x0.PATECOM
    self.__objPATECOM= <win32com.gen_py.CATIA V5
BOEPATEAutomationInterfaces Object 
                       Library.PATECOM instance at 0x44540104>
    Traceback (moste recent call last):
    File testKBE_PATECAKE.py, line 370 in ConnectToENOVIA
       self.__objPATECOM.SetApplicationID(strApplicationID)
   File "C:\Python27\lib\site-packages\win32com\gen_py\9BB3CB79
-7098-47D0-83A2-F8
           F56D236DC8x0x0x0.py", line 457 in SetApplicationID
       return self._oleobj_.InvokeTypes(1610940417, LCID, 1, (24, 0),
((16396, 1),), iAID
   File "C:\Python27\lib\site-packages\win32com\client\dynamic.py", line
516 in __getattr__
    raise AttributeError("%s.%s" % (self._username_, attr))
AttributeEror: CATIA.Application.InvokeTypes

----------------------------------------------------------------------

Comment By: Mark Hammond (mhammond)
Date: 2012-05-15 17:34

Message:
Can you please modify your test code to add:

print self.objCATIA

After creating it, and tell me what it prints in both the failing and
working cases?

----------------------------------------------------------------------

Comment By: Mike Fox (mike_fox)
Date: 2012-05-15 17:32

Message:
To Mark Hammond:
I don't think the problem is caused by a pre-existing wrapper in the gen_py
folder as you suggested in your comment.  When I uninstalled version 2.17
of pywin32 and installed version 2.16 on the same PC (with the contents of
the gen_py folder unchanged) I was able to call the SetApplicationID method
without it throwing an error.

----------------------------------------------------------------------

Comment By: Mark Hammond (mhammond)
Date: 2012-05-11 19:51

Message:
I suspect the problem is that previously you have makepy support generated
for the 'CATIA.Application' object which should make things work.  The
problem is that when you do:

self.__objPATECOM = self.objBase(self.objCATIA)

The DispatchBaseClass.__init__ function in win32com\client\__init__.py
checks to see if the object is itself a makepy generated object and will
work correctly if it is.

Even though, this really is a bug as we should handle that situation.  A
fix would probably be to change the line in DispatchBaseClass.__init__
from:

		elif isinstance(oobj, DispatchBaseClass):
to
                elif hasattr(oobj, "_oleobj_"):

----------------------------------------------------------------------

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[pywin32-bugs] [ pywin32-Bugs-3525912 ] InvokeTypes error using win32com v2.17

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[pywin32-bugs] [ pywin32-Bugs-3525912 ] InvokeTypes error using win32com v2.17