querying through wmi & win32.client objects with python

Question

Hi all,

Could someone shed some lights upon querying through wmi and win32.client objects?

Anytime i try to query throught win32.client object i get this error:

Error: '' object has no attribute 'UserName'

though, i know (wmic class "Win32_ComputerSystem", wmiexplorer etc.) the certain attribute belongs to the object i'm trying to query on:

import win32com.client
...
strComputer = "."
objWMIService = win32com.client.Dispatch("WbemScripting.SWbemLocator")
objSWbemServices = objWMIService.ConnectServer(strComputer,"root/cimv2")
colItems = objSWbemServices.ExecQuery("Select * from Win32_ComputerSystem")
for objItem in colItems:{
    print objItem.UserName    #Error: '' object has no attribute 'UserName'
}
...

And when i run query on wmi object - everything is just fine:

import wmi
...
c = wmi.WMI()
for objItem in c.query(colItems):{
    print objItem.UserName  # this works now
}
...

What is causing this "no attribute" error? Could this be my OS issue? Running winXP pro, version 2002, sp2. Or is this because of python 2.4 version i am working on?

Answer 1

Why are you doing this?

for objItem in colItems:{
    print objItem.UserName    #Error: '' object has no attribute 'UserName'
}

What causes you to think that the resulting columns will be attributes of the resulting object?

Try this to debug the problem.

for objItem in colItems:{
    print dir(objItem)
}

What actual attributes does it have? Perhaps the columns are identified by number? Perhaps you should be doing objItem[0]?

---

Edit

what caused the change of attributes in class "Win32_ComputerSystem"??

Nothing. Attributes don't change. The class is not what you think it should be.

Here's another debugging aid.

colItems = objSWbemServices.ExecQuery("Select * from Win32_ComputerSystem")
print type(colItems)
print dir(colItems)

Answer 2

Okay guys, here is another piece of code (from http://win32com.goermezer.de/content/view/211/189/):

import win32com.client
strComputer = "."
objWMIService = win32com.client.Dispatch("WbemScripting.SWbemLocator")
objSWbemServices = objWMIService.ConnectServer(strComputer,"root\cimv2")
colItems = objSWbemServices.ExecQuery("Select * from Win32_Environment")
for objItem in colItems:{
    print "Caption: ", objItem.Caption
    print "Description: ", objItem.Description
    print "Install Date: ", objItem.InstallDate
    print "Name: ", objItem.Name
    print "Status: ", objItem.Status
    print "System Variable: ", objItem.SystemVariable
    print "User Name: ", objItem.UserName
    print "Variable Value: ", objItem.VariableValue
}

And again the same error is being displayed:

Caption: Error: '' object has no attribute 'Caption'

What is happening? How come class is different from the specified one in ExecQuery? I mean, if one says "Select * from Win32_ComputerSystem", how can it query different class than Win32_ComputerSystem?

By the way, I am running python 2.4 code through spyce 2.0.3 server.

p.s. I found that brackets {} is one way to get python code block interpreted right - otherwise "expected an indented block" error is thrown

Answer 3

To find out about the "keys" and "values" in WMI query result, you can use "Properties_"

from win32com.client import Dispatch, GetObject import win32con
server = Dispatch("WbemScripting.SWbemLocator")
c = server.ConnectServer("localhost", "root\\cimv2") 
p = c.ExecQuery("Select * from Win32_OperatingSystem")

for i in w.p[0].Properties_:
    print i.Name, " = ", i.Value