Set win32 environment variable on startup via python

winpath_startup.py

# This must be run with Administrator privileges in order to set environment variables
# http://code.activestate.com/recipes/55993/, Wolfgang Strobl

import _winreg
import sys
import traceback
import win32gui
import win32api

# this ensures that changes propagate immediately
def RefreshEnvironment():
	""" A method by Geoffrey Faivre-Malloy and Ronny Lipshitz """
	# broadcast settings change
	HWND_BROADCAST = 0xFFFF
	WM_SETTINGCHANGE = 0x001A
	SMTO_ABORTIFHUNG = 0x0002
	sParam = "Environment"

	res1, res2 = win32gui.SendMessageTimeout( HWND_BROADCAST, WM_SETTINGCHANGE, 0, sParam, SMTO_ABORTIFHUNG, 100 )
	if not res1:
		print( "result: %s, %s, from SendMessageTimeout" % (bool(res1), res2) )
		
	
def SetSystemEnvironmentVariable( name, value ):
	try:
		# connect
		reg = _winreg.ConnectRegistry( None, _winreg.HKEY_LOCAL_MACHINE )
		env = _winreg.OpenKey( reg, r"SYSTEM\CurrentControlSet\Control\Session Manager\Environment", 0, _winreg.KEY_ALL_ACCESS )
		
		# set the value
		_winreg.SetValueEx( env, name, 0, _winreg.REG_EXPAND_SZ, value )
		
		# cleanup
		_winreg.CloseKey( env )
		_winreg.CloseKey( reg )
		
		# make sure changes propagate immediately. Without this call,
		# changes will appear under the Properties and Environment Variables,
		# but new command prompts do not reflect these changes
		RefreshEnvironment()
	except:		
		traceback.print_exc( file=sys.stdout )

# this script will update the PATH environment variable to include these paths
paths = []
paths.append( r"c:\python27" )
paths.append( r"c:\python27\scripts" )
paths.append( r"c:\cygwin\bin" )

# compile the new path
current_path = win32api.GetEnvironmentVariable( 'PATH' )
for path in paths:
	current_path += ';' + path

# set the path
SetSystemEnvironmentVariable( 'PATH', current_path )