articles tagged with irc

Occasionally you’ll find me in IRC using the old school Irssi client. Its a simple and powerful IRC client that most importantly, I can launch on any unix based server and leave running in a screen session. A little something like this;

screen irssi
# Ctrl+A,D to unhook this screen
# screen -x to jump back into it (when you've only 1 screen open)

Doing this on a remote server, means I’m always connected to IRC. I can easily jump back in to previous conversations by ssh’ing to the server and switching to the screen.

What I wanted was a growl notification every time my name (nick) was mentioned in a room, or I received a private message. I stumbled on a few blog posts explaining how to do this, but came across a few gotchas on OSX, so here goes another explanation.

fnotify

First, on the remote server (where irssi will run under screen), add the fnotify script to your own ~/.irssi/scripts folder. This is a handy perl script that will write any messages referencing your nick, to a local file (by default ~/.irssi/fnotify). fnotify is a good, simple example of irssi perl scripting.

Don’t forget (as I did) to load this script in irssi with the following command (or setup irssi to auto load it on startup, some instructions here)

/script load fnotify.pl

Check this is working by having someone mention your name in a chat room (or pm you). You should see the ~/.irssi/fnotify file fill with these messages.

Growl

Next on OSX, install growl (if you haven’t already) and be sure to install the growlnotify script (make it executable and in your PATH e.g. /usr/local/bin) Test its working in your OSX terminal with something like;

growlnotify -m 'it works!'

SSH & connection script

Now if you haven’t already got one, create an SSH user with a key to login to your remote server. The key can have a pass-phrase. If you do choose to set one, for the following script to run without interruption, you’ll have to let OSX remember the pass-phrase in its key-chain.

Finally the client script, in OSX create the following script in ~/irssi_growler

#!/bin/sh

(ssh ssh_username@your_server.com -o PermitLocalCommand=no  \
  ": > .irssi/fnotify ; tail -f .irssi/fnotify " |  \
while read heading message; do                      \
  growlnotify -s -t "${heading}" -m "${message}";      \
  say "${heading} says, ${message}";                \
done)&

Replace your ssh_username and your_server.com details, make it executable (644) and run it. This script does the following;

• opens an ssh connection to your remote machine
• runs the tail -f command to remotely tail the ~/.irssi/fnotify command
• the output of which is piped to a read while loop
• in this loop each message is sent to growlnotify, and (for an audio bonus) to the say command too :)
• the growl message is set to be sticky (-s) and will stay onscreen until you click to hide it

Launch at startup

After numerous attempts (on Snow Leopard) trying to get this script automatically launching at startup (using launchctl, .plist’s, automator etc. etc.) I opted to just add the script to my login items. This does leave a Terminal window open every-time I login, but I can live with that for now. If someone can explain how properly add a bash script to launch on startup (as a daemon) on the latest Snow Leopard, please let me know.

The final caveat I hit was my firewall. It was smart enough to close any open SSH session after a period of inactivity. This kept killing the irssi_growler script. To prevent this I changed my ssh client config (in /etc/ssh_config) with the following ‘keep alive’ settings;

ServerAliveInterval 150 # can be adjusted higher or lower
ServerAliveCountMax 3

In the future I might re-write fnotify to do more that just write to file. It could potentially send the message data via tcp/ip to the a growl client (set to accept incoming connections).

I think IRC is a vastly under-rated tool. It is somthing I used a lot in the mid/late 90’s and in my first few years at University on the old DEC Workstations. Back before Skype and before the web was getting ready for its next version number, IRC was the best way to chat online.

For a long time I forgot about IRC, until it became obvious that (with a channel bot) it can be useful for all sorts of things, beyond just regular chat. With a bot parsing and watching RSS feeds, your channel can include notifications for just about anything you want, SVN commits, Trac tickets, even exceptions thrown from your code (you’ll have to build a feed for that yourself).

So I looked into setting up a channel bot myself (something I haven’t done before). Looking around I played with infobot (Perl) and eggdrop (C/TCL) – before (rather predicatably) going with RBot (Ruby) I had a little hassle getting the bot to work on Debian. It requires the Berkley Database (and Ruby’s binding to it).

Of course the BDB that comes with GNU/Debian Linux (apt-get) is out of date, and you will need to compile the most recent version instead. If you already installed Berkeley DB on your Debian Box, uninstall it to prevent conflicts. Then get it from here (./configure, make, make install). Choose BDB 4.4 or lower since the Ruby BDB bindings are not compatible with the new 4.5) – I couldn’t find all of those caveats documented together in the one place, so that may be of use to someone.

Next grab Ruby’s BDB bindings – and finally make sure you can call the bdb library in irb. If you can do,

:~$ irb
>> require 'bdb'
=> true

- without throwing an error, then download and install RBot. Its fairly simple to setup and there are a large number of plugins to play around with. Rbot will install a some of these by default (including rss.rb) and you can extend them, or write your own in the bot’s local plugin directory.

To persist the bot, use a simple ‘keep alive’ script;

#!/bin/bash

proc=`ps -fu $LOGNAME | grep name_of_your_bot | grep -v grep | wc -l`
if test $proc -eq 0
then
 nohup rbot /home/username/.name_of_your_bot > /dev/null &
fi

And put it in a cron job to check its running (e.g. every 55 minutes);

# make sure rbot is running all the time
*/55 * * * * /home/username/rbotchk.sh

My work in progress Rbot (kafka) is sitting in #komura on irc.perl.org – expect it to be broken most of time as I add a few plugins and try stuff out.

While there are hundreds of IRC clients available, I have stuck to using IRSSI (a terminal client) its old-fashioned (I know), but simple and I can access it from anywhere (keeping it running on a screen). I’d also recommend Colloquy a decent graphical client for OSX.