OfflineIMAP, ConsoleKit, GNOME Keyring

Over the weekend I finally got fed up with Evolution struggling to connect to work's "IMAP" server (Exchange 2007), and switched to using OfflineIMAP to sync the mail to a local Maildir. This as expected worked pretty well, and I'm now hidden from the nasty lag on the server. However, I've had to write my top secret Intel password into .offlineimaprc, which sucks. Then I had a cunning plan...

GNOME Keyring will store passwords in a pretty secure manner, so somehow I need to fetch the password from there. A quick look at the OfflineIMAP manual revealed that I can write Python functions which return the password, so I should be abe to hook into the keyring from OfflineIMAP. This should be fairly simple:

import gobject, gnomekeyring

# The keyring needs to know the application name
if gobject.get_application_name() is None:
  gobject.set_application_name("offlineimap")

def keyring(user, host):
  keys = gnomekeyring.find_network_password_sync(user=user, server=host, protocol="imap")
  # First one will do nicely thanks
  return keys[0]["password"]
...
remotepasseval = keyring("rburton", "imapmail.intel.com")

After writing a small tool to add the key to the keyring, to my surprise this worked first time. I bounced with glee, but ten minutes later I had error messages from OfflineIMAP running from cron in my inbox...

GNOME Keyring uses an environment variable to find the daemon, which isn't set in a cron environment. GNOME Keyring will fall back to using DBus to find the daemon, but the DBus session bus environment variable isn't set. DBus will fall back to reading the session bus address from the X root window, but DISPLAY isn't set so that doesn't work either... EPIC FAIL.

But, I thought, I upgraded to Network Manager 0.7 last week which bought in ConsoleKit. If I ask ConsoleKit for my sessions I should be able to find a session with has an X connection, then I can set DISPLAY appropriately and then the chain described above will work, and I'll have my password. Shockingly, this worked first time too:

import dbus, os
if not os.getenv("DISPLAY"):
  # Get the ConsoleKit manager
  bus = dbus.SystemBus()
  manager_obj = bus.get_object('org.freedesktop.ConsoleKit', '/org/freedesktop/ConsoleKit/Manager')
  manager = dbus.Interface(manager_obj, 'org.freedesktop.ConsoleKit.Manager')
  
  # For each of my sessions..
  for ssid in manager.GetSessionsForUnixUser(os.getuid()):
    obj = bus.get_object('org.freedesktop.ConsoleKit', ssid)
    session = dbus.Interface(obj, 'org.freedesktop.ConsoleKit.Session')
    # Get the X11 display name
    dpy = session.GetX11Display()
    if dpy:
      # If we have a display, set the environment variable
      os.putenv("DISPLAY", dpy);
      break

(man, I really with python-dbus had a better syntax for getting objects with a specific interface)

So there you go, integrating OfflineIMAP with the GNOME Keyring via ConsoleKit and DBus. Surprisingly this was pretty easy to do, thanks to DBus and the magic provided by ConsoleKit it is 100% hack free.

20:00 Tuesday, 04 Nov 2008 [#] [computers] ( comments)