dbus

D-Bus is a simple, message-based protocol for inter-process communication, which allows applications to interact with other parts of the machine and the user's session using remote procedure calls.

D-Bus is a essential part of the modern Linux desktop, where it replaces earlier protocols such as CORBA and DCOP.

This library is an implementation of the D-Bus protocol in Haskell. It can be used to add D-Bus support to Haskell applications, without the awkward interfaces common to foreign bindings.

Example: connect to the session bus, and get a list of active names.

{-# LANGUAGE OverloadedStrings #-}

import Data.List (sort)
import DBus
import DBus.Client

main = do
    client <- connectSession
 
    -- Request a list of connected clients from the bus
    reply <- call_ client (methodCall "/org/freedesktop/DBus" "org.freedesktop.DBus" "ListNames")
        { methodCallDestination = Just "org.freedesktop.DBus"
        }
 
    -- org.freedesktop.DBus.ListNames() returns a single value, which is
    -- a list of names (here represented as [String])
    let Just names = fromVariant (methodReturnBody reply !! 0)
 
    -- Print each name on a line, sorted so reserved names are below
    -- temporary names.
    mapM_ putStrLn (sort names)

$ ghc --make list-names.hs
$ ./list-names
:1.0
:1.1
:1.10
:1.106
:1.109
:1.110
ca.desrt.dconf
org.freedesktop.DBus
org.freedesktop.Notifications
org.freedesktop.secrets
org.gnome.ScreenSaver