import _winreg
import os

global __debug__
__debug__ = True

def walkRegistry(regkey, keyToSearch="file_locations",
                 valueNameToSearch="temp_dir", verbose=False):
    """Recursively search the Windows registry (HKEY_CURRENT_USER),
    starting at top <regkey>. Return a list of three tuples that contain
    the registry key, the value and the associated data"""
    if verbose:
        print regkey
    aReg = _winreg.OpenKey(_winreg.HKEY_CURRENT_USER, regkey)
    i, keys, founds = 0, [], []
    try:
        while True:
            i += 1
            key = _winreg.EnumKey(aReg, i)
            keys.append(key)
            if key == keyToSearch:
                keyx = os.path.join(regkey, key)
                aReg = _winreg.OpenKey(_winreg.HKEY_CURRENT_USER, keyx)
                data, type_ = _winreg.QueryValueEx(aReg, valueNameToSearch)
                founds.append((keyx, valueNameToSearch, data))
    except WindowsError:
        for key in keys:
            try:
                new_regkey = os.path.join(regkey, key)
                walkRegistry(new_regkey, keyToSearch,
                             valueNameToSearch, verbose)
            except WindowsError:
                pass
    return founds

def setRegistry(regkey, keyToSet, valueToSet, replacementData, verbose=False):
    """Search for <keyToSet> starting at top <regkey>. If <keyToSet> is found
    exactly once, replace registry data associated with <valueToSet> with
    <replacementData>."""
    founds = walkRegistry(regkey, keyToSet, valueToSet, verbose)
    if not founds:
        return
    elif len(founds) == 1:
        keyx, valueNameToSearch, data = founds[0]
    else:
        msg = "Registry value %r is found multiple times"
        raise ValueError(msg % valueToSet)

    if not __debug__:
        try:
            key = _winreg.OpenKey(_winreg.HKEY_CURRENT_USER, keyx,
                                  0, _winreg.KEY_ALL_ACCESS)
        except:
            key = _winreg.CreateKey(_winreg.HKEY_CURRENT_USER, regkey)
        _winreg.SetValueEx(keyx, valueToSet, 0, _winreg.REG_SZ,
                           replacementData)
        _winreg.CloseKey(keyx)

regkey = u"Software\\Microsoft\\Windows\\CurrentVersion\\Explorer"
print founds = walkRegistry(regkey, u"Shell Folders", u"Cookies", True)
setRegistry(regkey, u"Shell Folders", u"Cookies", "this is the replacement value", False)