import ctypes
import _winreg

# See http://msdn.microsoft.com/en-us/library/aa385328(v=vs.85).aspx
#: Causes the proxy data to be reread from the registry for a handle. No buffer is required. This option can be used on the HINTERNET handle returned by InternetOpen. It is used by InternetSetOption.
INTERNET_OPTION_REFRESH = 37
#: Notifies the system that the registry settings have been changed so that it verifies the settings on the next call to InternetConnect. This is used by InternetSetOption.
INTERNET_OPTION_SETTINGS_CHANGED = 39
# setup function
Wininet = ctypes.windll.Wininet
InternetSetOption = Wininet.InternetSetOptionW

HKEY_CURRENT_USER = _winreg.HKEY_CURRENT_USER
SUB_KEY_PATH = r'Software\Microsoft\Windows\CurrentVersion\Internet Settings'

def main():
    hkey = _winreg.OpenKey(HKEY_CURRENT_USER, SUB_KEY_PATH, 0, _winreg.KEY_READ | _winreg.KEY_WRITE)
    (ProxyEnabled, _) = _winreg.QueryValueEx(hkey, 'ProxyEnable')
    _winreg.SetValueEx(hkey, 'ProxyEnable', 0, _winreg.REG_DWORD, not ProxyEnabled)
    print 'enabled' if not ProxyEnabled else 'disabled'

    InternetSetOption(0, INTERNET_OPTION_REFRESH, 0, 0)
    InternetSetOption(0, INTERNET_OPTION_SETTINGS_CHANGED, 0, 0)

if __name__ == '__main__':
    main()