[Xmonad] Re: Remote Controlling XMonad: Cases and Materials

[Andrea Rossato]

On Mon, Jul 30, 2007 at 08:47:11PM +0200, Tobias Hammerschmidt wrote:
>  I like the idea too! Maybe this is a little bit off-topic but why don't
>  use a standard like dbus? There are allready some haskell bindings out
>  there (http://neugierig.org/software/hdbus/ -- ok they were not updated
>  for about a year but maybe it could be a point to start from though).

well, we could have a look at dbus too, but the problem is finding a
way to listening for external commands without blocking XMonad (which
is already blocked, in the "forever" loop, by nextEvent).

I can send commands through a socket (very easy, see example below),
but how can I get XMonad to wait over a socket without blocking the
main thread? Concurrency is not going to give us an easy solution,
AFAIK.

Perhaps it's just me, but I find this problem quite difficult.

If you have any idea please let me know.

All the best,
Andrea


1. Save this as XMonadContrib/ServerMode.hs
-----
module XMonadContrib.ServerMode
import Network
import System.IO
import XMonadContrib.Commands

serverMode :: X ()
serverMode = do
  com <- io $ serverMode'
  runCommand' com
  -- if I now add a line with "serverMode" XMonad is not very useful anymore...;-)

serverMode' :: IO String
serverMode' = do
  s <- listenOn (PortNumber 6913)
  (h, hn, pn) <- accept s
  hSetBuffering h NoBuffering
  sClose s
  com <- hGetLine h
  hClose h
  return com
----

2. import it from Config.hs
3. add a key binding that calls serverMode
4. use this code to send commands (you can run one command then
serverMode must be restarted. XMonad will be blocked till a command is
recieved)

---
module Main where

import System.Environment
import System.Exit
import Network

usage :: String -> String
usage n = "Usage: " ++ n ++ " command\nSend a command to a running instance of XMonad"

main :: IO ()
main = do
  args <- getArgs
  pn <- getProgName
  let com = case args of
              [] -> error $ usage pn
              w -> (w !! 0)
  sendTo "localhost" (PortNumber 6913) com
  exitWith ExitSuccess