[mod_python] win32com and session issues

gmilas at sunstoneinc.com gmilas at sunstoneinc.com
Thu Jul 29 14:20:12 EDT 2004

Hi everyone,

My environment is Apache/2.0.50 (Win32) mod_python/3.1.3 Python/2.3 with a
PSP handler and Windows is 2000 professional.
Apache service runs under my user name which has administrator privileges.

I would like to keep a database connection open during a period of time and
I am trying to do it using the session mechanism. I'm trying this because I
have a bunch of code I had written before for IIS/ASP/Python and I have a
few helper classes to help me abstract away the environment, so I'm trying
to get my code as it is out of IIS to Apache.
Almost everything is fine except because I've used session to persist
database connection in my IIS, I am trying now the same thing but the
object that is being stored in the session does not come out "clean".

Anyway, is there a way to keep an ADODB.Connection object in a session
field reliably?
It seems like it is but when I try to use the connection from a session
field it gives me all sorts of errors. To what  I can say it looks like the
object stays around but it is closed and I can not reuse it actually. And
to reopen it defeats the purpose.

The code is basically something like this only hidden away in my helper

import win32com.client
if con is None:
      con = win32com.client.Dispatch('ADODB.Connection')

cmd = win32com.client.Dispatch("ADODB.Command")
cmd.ActiveConnection = con
cmd.CommandText = "select * from MyUsers"
Now if I run the code like above and work with con and cmd inside the PSP
file it always work.

Now if I create con and/or cmd inside some modules that I import in my PSP
file it works the first time, but when using con from the session it will
give me cmd.ActiveConnection can not be set .

 File "C:\Python23\lib\site-packages\win32com\client\dynamic.py", line 504,
in __setattr__
    raise AttributeError, "Property '%s.%s' can not be set." %
(self._username_, attr)
AttributeError: Property 'ADODB.Command.ActiveConnection' can not be set.

I also tried creating the "command" objects in my PSP file and pass it to
my classes and that does not work neither, I will have the same error.

I've also tried a "PythonImport win32com.client" because I hoped that if
there is some module global stuff in win32com.client.dynamic (which seems
that there is as I looked in the code) then it would stay around but I
could not make this work, I mean it gives me an error like "PythonImport
not allowed here" or otherwise it gives me no error, at least not in apache
log files, but just simply won't start the server.
httpd.conf looks like the following:
<VirtualHost *:80>
ServerName mysite.gheorghe.com
  <Directory ...>
    AddHandler mod_python .asp .asp_ .psp .psp_
    PythonHandler mod_python.psp
    #PythonImport win32com.client mysite.gheorghe.com #the server won't
start using this (python interpreter is that according to req.interpreter)
    PythonAutoReload On
    PythonDebug On

I've read that if I was to use a different handler, that I write myself, I
could set the connection as a global variable and it would stay there for
successive requests, but I'm trying to use psp and move the code as I have
it already working on IIS/ASP where I used session successfully. The
session seems to be memory session (session.__class__.__name__ is
MemorySession) so fields are in a global dictionary (aren't they), so is
the same as if I was using a different handler and my own global variables,
isn't it?

Please forgive my bad English, and I would really, really appreciate some
help as this is very frustrating not understanding what is going on.
Gheorghe Milas
gmilas at sunstoneinc.com

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