Gnome: An icon in the system tray (new mail)

This should have been obvious: Have a “new mail” icon in the system tray when new mail is fetched by Thunderbird on a FC12 Linux machine. I ended up writing my own script.

My starting point was the “Gnome Integration” add-on. Not that I liked that it forced me to have another notification popup on new mails (aside from Thunderbird’s native one) if I wanted the icon. But when an icon was added to the system tray for each new mail arriving (that is, a lot of icons in the tray), I knew I had to do a thing of my own.

So I wrote a small, and not so sophisticated script, which checks if an icon is there (more precisely: If a process owning the icon is running) and gives up if it already exists.

The lucky things about the “Gnome Integration” add-on is that it allows choosing the command for the mail notification. So instead of running whatever puts that unnecessary popup, it runs my script, which puts the icon in place if necessary. Popup away, single icon instead. Could I ask for more?

Here’s the script. I saved it as /usr/local/bin/new-mail-icon (you can put it anywhere you want, but make sure the executable has the same name):

#!/bin/bash

THEDIR=$HOME/.thunderbird
ICON=$THEDIR/green-mail-unread.png
LOCKFILE=$THEDIR/new-mail-icon-process

NOW=`date "+%F %T"`

if [ -e $LOCKFILE ] && grep new-mail-icon /proc/`cat $LOCKFILE`/cmdline > /dev/null 2>/dev/null ;
 then exit 0;
else
 ( echo $BASHPID > $LOCKFILE
 zenity --notification --window-icon=$ICON --text="New mail on $NOW"
 rm -f $LOCKFILE
 ) &
fi

Important notes about the script:

• It relies on that the script’s name is “new-mail-icon”. This is how it detects another icon exists. If the script has another name, several icons will appear. Or change the argument to the grep command.
• There is a slight race condition if two of these scripts are run in parallel (which is an unlikely situation, and still). It’s possible that more than one icon will appear, if two (or more) scripts race on the little time gap between checking for the locking file and writing to it.

The script above doesn’t just check if the lockfile exists, but also verifies that the process holding it exists and has the correct command line. This makes it behave correctly if the system shuts down or crashes, leaving the lock file in place.

Then set the Gnome Integration add-on preferences as follows. Note that the “Show icon” is not checked. The icon is created by running my script instead of the notification application. It’s a hack indeed.