Programmatically detect system-proxy settings on Windows XP with Python

Question

I develop a critical application used by a multi-national company. Users in offices all around the globe need to be able to install this application.

The application

Answer 1

As far as I know, In a Windows environment, if no proxy environment variables are set, proxy settings are obtained from the registry's Internet Settings section. . Isn't it enough?

Or u can get something useful info from registry: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ProxyServer

Edit:
sorry for don't know how to format comment's source code, I repost it here.

>>> import win32com.client
>>> js = win32com.client.Dispatch('MSScriptControl.ScriptControl')
>>> js.Language = 'JavaScript'
>>> js.AddCode('function add(a, b) {return a+b;}')
>>> js.Run('add', 1, 2)
3

Answer 2

Here's a sample that should create a bullet green (proxy enable) or red (proxy disable) in your systray

It shows how to read and write in windows registry

it uses gtk

#!/usr/bin/env python
import gobject
import gtk
from _winreg import *

class ProxyNotifier:
    def __init__(self):        
        self.trayIcon = gtk.StatusIcon()
        self.updateIcon()

        #set callback on right click to on_right_click
        self.trayIcon.connect('popup-menu', self.on_right_click)
        gobject.timeout_add(1000, self.checkStatus)

    def isProxyEnabled(self):

        aReg = ConnectRegistry(None,HKEY_CURRENT_USER)

        aKey = OpenKey(aReg, r"Software\Microsoft\Windows\CurrentVersion\Internet Settings") 
        subCount, valueCount, lastModified = QueryInfoKey(aKey)

        for i in range(valueCount):                                           
            try:
                n,v,t = EnumValue(aKey,i)
                if n == 'ProxyEnable':
                    return v and True or False
            except EnvironmentError:                                               
                break
        CloseKey(aKey)  

    def invertProxyEnableState(self):
        aReg = ConnectRegistry(None,HKEY_CURRENT_USER)
        aKey = OpenKey(aReg, r"Software\Microsoft\Windows\CurrentVersion\Internet Settings", 0, KEY_WRITE)
        if self.isProxyEnabled() : 
            val = 0 
        else:
            val = 1
        try:   
            SetValueEx(aKey,"ProxyEnable",0, REG_DWORD, val) 
        except EnvironmentError:                                          
            print "Encountered problems writing into the Registry..."
        CloseKey(aKey)

    def updateIcon(self):
        if self.isProxyEnabled():
            icon=gtk.STOCK_YES
        else:
            icon=gtk.STOCK_NO
        self.trayIcon.set_from_stock(icon)

    def checkStatus(self):
        self.updateIcon()
        return True


    def on_right_click(self, data, event_button, event_time):
        self.invertProxyEnableState()
        self.updateIcon()


if __name__ == '__main__':
    proxyNotifier = ProxyNotifier()
    gtk.main()