[python-win32] WMI troubles!

[Alex Hall]

Hello all,
I just joined this list. I am pretty new to Python, but I really like and 
hope to get more into it; right now, it is my second-favorite, second only 
to java. I am a computer science major in my third year and currently only 
program as a hobby/for something to do. Also, I am blind so I use JAWS for 
Windows (from http://www.freedomscientific.com) to do all my computer work; 
basically, this program reads me the screen. I only mention this so the 
projects I am doing make sense and so you understand why suggesting things 
like looking at a diagram or an animation will not work.

Anyway, onto the problem. I am working on a simple resource monitor (I have 
never found one that works well with screen readers, so I am writing one). I 
am using python2.6 with all the win32 libs installed. My monitor will use 
wmi to get all of its information, and it was going pretty well until a few 
hours ago, when I started receiving seemingly random errors. I can call my 
functions, such as getFreeRam or getLoad, with no problem as long as the 
call is hard-coded into the script. However, when I try to call said 
functions from a function monitoring keyboard input (using pyHooks), I get 
an error and the program crashes (at least it did until I put a try/except 
in there, but hitting the hotkey over and over always gives me an error). I 
will paste the entire file below. It is not very commented yet, so if 
something does not make sense, please let me know. My questions are:

1. Why am I getting these errors?

2. The getLoad function only returns one number (the counter is there to 
double check that the loop really only runs once). I have a dual core AMD, 
so I expected two numbers, a LoadPercentage for each core, not just one 
number. How do I get the load per core, not per physical processor?

3. Regarding pyHook: I press my win-` hotkey on the desktop and get 
something to happen in my script, which is good. However, I also get a 
Windows error sound. Is there a way to grab that keystroke before Windows 
can get it to avoid what seems to be passing the keystroke to the active app 
before my script can get it? I tried returning False in my keyUp function 
but that made no difference.

I am running Windows 7 Home Premium, 64 bit, on an AMD processor whose exact 
model escapes me. It is clocked at around 2.4ghz and I have 4gb of 800mhz 
ddr2 ram. The pc was built by my friend and I from Newegg parts, but has 
worked well for the last 18 months (seeing three different operating 
systems). Win7 was installed a few days ago, so I am pretty sure there is no 
problem with my installation as far as wmi goes. I tried to run the wmi 
diagnostic utility, but I got an error; I figure the utility cannot run in 
64 bit, but I am not sure. Anyway, any help here would be greatly 
appreciated. This is my first "real" project in python, so go easy on my 
stupid mistakes. :) Thanks!


CODE

import os, sys, wmi, win32com.client, pyHook, pythoncom

pythoncom.CoInitialize() #a forum post said I should put this...

win=0 #is either Windows key pressed?
ctrl=0 #either control key pressed?
alt=0 #what about either alt key?
#for speaking text with the user's active screenreader, or sapi if no reader
#http://www.empowermentzone.com/saysetup.exe
speaker=win32com.client.Dispatch("Say.Tools")
c=wmi.WMI("localhost") #for WMI access

def getLoad():
 i=0
 #get proc load, currently only first core for some reason
 for p in c.Win32_Processor():
  load=p.LoadPercentage
  i=i+1
 # end for
 speaker.say(str(load)+", looped "+str(i)+" times.")
 return(load)
#end def
#following works just fine here, but not when called later in keyUp method
getLoad()

def getFreeRam():
 #get total ram and ram available
 for info in c.Win32_OperatingSystem():
  ram=info.TotalVisibleMemorySize
  freeRam=info.FreePhysicalMemory
 #end for
 return(float(freeRam)/float(ram)*100) #return free ram as %
#end def

def toBiggestBytes(n):
 #returns a string where n is in the largest logical measure possible
 i=0 #counter
 units=[" bytes","kb","mb","gb","tb"]
 while(n>=1024):
  n=n/1024
  i=i+1
 return(str(n)+units[i])
#end def

#following does not work: why?
"""
for t in c.MSAcpi_ThermalZoneTemperature():
 temp=t.CurrentTemperature
# end for
"""

"""
#old interface used for early testing
end=0
while(end==0):
 lr=raw_input("\nr for ram, l for CPU load, e to exit.\n")
 if(lr=='r'):
  pRam=int(ram)/1024/1024
  speaker.say(str(pRam)+"mb total RAM")
 if(lr=='l'):
  speaker.say(str(load)+"% for core 1")
 if(lr=='e'):
  end=1 #exit loop
 #endif
#end while
"""


#Copied directly from example.py in the pyHook folder, then modified
def OnKeyDownEvent(event):
 global win
 global ctrl
 global alt
 if(event.KeyID==91 or event.KeyID==92):
  #user is pressing a Windows key, so set flag
  win=1
 #endif
 # return True to pass the event to other handlers
 # return False to stop the event from propagating
 return True
#end def

def OnKeyUpEvent(event):
 global win
 global ctrl
 global alt
 if(event.KeyID==91 or event.KeyID==92):
  #user released the Windows key, so unset flag
  win=0
 #endif
 if(win==1 and chr(event.Ascii)=='`'):
  try:
   speaker.say(str(getLoad()))
  except:
   speaker.say("Stupid errors!")
  #end except
 #endif
 return True
#end def

# create the hook mananger
hm = pyHook.HookManager()
# register two callbacks
hm.KeyDown = OnKeyDownEvent
hm.KeyUp = OnKeyUpEvent

# hook into the keyboard event
hm.HookKeyboard()

if __name__ == '__main__':
  import pythoncom
  pythoncom.PumpMessages()

#end copying/modifying

speaker=None; #release speaker object


#reference so I know what properties I can get
"""
  print 'MessageName:',event.MessageName
  print 'Message:',event.Message
  print 'Time:',event.Time
  print 'Window:',event.Window
  print 'WindowName:',event.WindowName
  print 'Ascii:', event.Ascii, chr(event.Ascii)
  print 'Key:', event.Key
  print 'KeyID:', event.KeyID
  print 'ScanCode:', event.ScanCode
  print 'Extended:', event.Extended
  print 'Injected:', event.Injected
  print 'Alt', event.Alt
  print 'Transition', event.Transition
  print '---'
"""

Have a great day,
Alex
Email: mehgcap at gmail.com