[python-win32] Re: Problems with Python+COM and XP Firewall Manager

[Thomas Heller]

Robert Olson <olson at mcs.anl.gov> writes:

> Hi -
>
> I'm trying to use python+COM to poke at the WinXP firewall
> configs. I'm looking at the VBScript sample available here:
>
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ics/ics/enabling_internet_connection_firewall_vbscript_.asp
>
> (aka http://snurl.com/qu2 ) and attempting to emulate it in Python. I
> used makepy to create a module for the ICS library:
>
> makepy -o hnet.py \windows\system\hnetcfg.dll
>
> I can create the INetSharingManager obj just fine, and invoke its
> toplevel methods, but can't use the objects returned from the
> enumeration.
>
> here's the test code:
[...]

Just for fun, I tried to convert this into corresponding ctypes code.

First, you have to run the readtlb.py tool on the hnetcfg.dll typelib:

  "readtlb.py c:\windows\system32\hnetcfg.dll > hnet_gen.py"

which creates a python wrapper containing the interfaces.  Second, I had
to manually write a wrapper for the IEnumVARIANT interface, which was
not yet wrapped by ctypes' com.  Easy:

from ctypes import *
from ctypes.com import IUnknown, GUID, STDMETHOD, HRESULT

class IEnumVARIANT(IUnknown):
    _iid_ = GUID("{00020404-0000-0000-C000-000000000046}")

IEnumVARIANT._methods_ = IUnknown._methods_ + [
        STDMETHOD(HRESULT, "Next", c_ulong, POINTER(VARIANT), POINTER(c_ulong)),
        STDMETHOD(HRESULT, "Skip", c_ulong),
        STDMETHOD(HRESULT, "Reset"),
        STDMETHOD(HRESULT, "Clone", POINTER(POINTER(IEnumVARIANT)))
        ]

And finally, after some experimentation and looking into the generated
hnet_get module, here is the script:

-----
import hnet_gen
from ctypes import *
from ctypes.com import CreateInstance
from ctypes.com.automation import IDispatch

def main():
    n = CreateInstance(hnet_gen.NetSharingManager)
    print "n=", n

    installed = c_int()
    n._get_SharingInstalled(byref(installed))
    print "sharingInstalled=", installed

    collection = POINTER(hnet_gen.INetSharingEveryConnectionCollection)()
    n._get_EnumEveryConnection(pointer(collection))

    count = c_long()
    collection._get_Count(byref(count))

    print "count", count

    enum = POINTER(IUnknown)()
    collection._get__NewEnum(byref(enum))

    print "enum", enum

    ienum = POINTER(IEnumVARIANT)()
    enum.QueryInterface(byref(IEnumVARIANT._iid_), byref(ienum))

    v = VARIANT()
    fetched = c_ulong()
    ienum.Next(1, byref(v), byref(fetched))
    print "Next?", fetched, v.vt
    item = v.value
    print "Got", item
    p = POINTER(hnet_gen.INetConnection)()
    item.QueryInterface(byref(hnet_gen.INetConnection._iid_), byref(p))
    print p
    guid = GUID()
    p.GetUiObjectClassId(byref(guid))
    print "GetUiObjectClassId", guid


if __name__ == "__main__":
    main()
-----

and here is what it prints:

n= <ctypes.LP_INetSharingManager object at 0x009871B0>
sharingInstalled= c_int(65535)
count c_long(5)
enum <ctypes.LP_IUnknown object at 0x00997AB0>
Next? c_ulong(1) 13
Got <ctypes.LP_IUnknown object at 0x0099D530>
<ctypes.LP_INetConnection object at 0x0099D4F0>
GetUiObjectClassId {7007ACC5-3202-11D1-AAD2-00805FC1270E}

Not to say that ctypes.com is ready for production use, but maybe it's
worth a look.

Thomas

PS: http://starship.python.net/crew/theller/ctypes/