I'm pleased to announce a small utility program I wrote recently. Today I pushed version 0.2.0.0 of mute-unmute to Hackage, from with you can cabal-install it right now (following the usual 'update' step). What it does? It's simple: it will mute the sound when you lock your screen and unmute it back again when you unlock it.

Why anyone would need such program? Well, this is a little bit more complicated.

I work in "open space" kind of office. It can get quite noisy there. I often sit with headphones on, but when I walk away from my desk I put them down and lock my screen. Here comes uncomfortable moment: when I remove my headphones suddenly people around me who doesn't use their headphones now start to hear the music I listen to. And they don't always like it, so I manually mute the sound to make happy.

But now, instead of doing this task by hand I have a program do it for me :-)

Unfortunately this kind of programs tend to be pretty much platform specific. Current version supports the recent versions of Gnome and KDE, but needs ALSA. It's quite common setup, but if you happen to have a different one you can easily hack the code (it's very straightforward) and send me patches. Patches are always welcome. The source repo is on Github and released versions are on Hackage:

~/ mute-unmute # first session, it will ask for configuration options

mute-unmute: Creating config directory...
mute-unmute: Mute config is missing...

Mute sound card and press RETURN

mute-unmute: Unmute config is missing...

Unmute sound card and press RETURN

mute-unmute: Session: UnixAbstract {addrPath = "/tmp/dbus-1tB1AEUcgg", addrGuid = Just "19ec85e3778816ad38a77bbf0000003f"}

mute-unmute: Connected
mute-unmute: Handler added: [MatchType Signal,MatchInterface "org.gnome.ScreenSaver",MatchMember "ActiveChanged",MatchPath "/org/gnome/ScreenSaver"]

mute-unmute: Handler added: [MatchType Signal,MatchInterface "org.freedesktop.ScreenSaver",MatchMember "ActiveChanged",MatchPath "/ScreenSaver"]

^C

~/ mute-unmute # remembers previous options which can be changed by calling with --store switch
mute-unmute: Session: UnixAbstract {addrPath = "/tmp/dbus-1tB1AEUcgg", addrGuid = Just "19ec85e3778816ad38a77bbf0000003f"}

mute-unmute: Connected
mute-unmute: Handler added: [MatchType Signal,MatchInterface "org.gnome.ScreenSaver",MatchMember "ActiveChanged",MatchPath "/org/gnome/ScreenSaver"]

mute-unmute: Handler added: [MatchType Signal,MatchInterface "org.freedesktop.ScreenSaver",MatchMember "ActiveChanged",MatchPath "/ScreenSaver"]

mute-unmute: Message {mType = Signal, mFlags = [NoReplyExpected], mSerial = 31, mPath = Just "/org/gnome/ScreenSaver", mInterface = Just "org.gnome.ScreenSaver", mMember = Just "ActiveChanged", mErrorName = Nothing, mReplySerial = Nothing, mDestination = Nothing, mSender = Just ":1.19", mBody = [Variant (True) {- b -}]}

mute-unmute: Lock screen
mute-unmute: Message {mType = Signal, mFlags = [NoReplyExpected], mSerial = 32, mPath = Just "/org/gnome/ScreenSaver", mInterface = Just "org.gnome.ScreenSaver", mMember = Just "ActiveChanged", mErrorName = Nothing, mReplySerial = Nothing, mDestination = Nothing, mSender = Just ":1.19", mBody = [Variant (False) {- b -}]}

mute-unmute: Unlock screen
^C

You can get usage information with --help switch:

~/ mute-unmute --help
mute-unmute
--store ask for mute and unmute configurations
--store-mute ask for mute configuration
--store-unmute ask for unmute configuration
-d --daemon wait for screensaver state changes
-h, -? --help show help

There isn't much more I can say. I hope you find the program at least educational (as a simple example of DBus usage) if not useful.

Krzysztof Skrzętnicki