Build IRC Bots with Node.js

One of the tasks on my WebDev bucket list has always been creating a functional IRC bot.  I have no clue why it's been high on my list, but ... it just has.  IRC bots are used for a variety of things:  Google search, keyword detection and information retrieval (i.e. a message with a bug number in Mozilla's IRC will fetch the title and link of the given bug), and more.  I recently found a Node.js library which allowed me to listen to common IRC events and respond to them;  better yet, it's incredibly easy to do.  Let me show you how to create your own IRC bot with JavaScript!

Node IRC Install

Use npm to install the IRC library:

npm install irc

This the only external library you will need!

Bot Configuration and Retrieval

Setting up a config object is recommended as many settings may be shared throughout the bot's event listeners:

// Create the configuration
var config = {
	channels: ["#davidwalshblog", "#mootools"],
	server: "irc.freenode.net",
	botName: "walshbot"
};

Then require the IRC library and create your bot:

// Get the lib
var irc = require("irc");

// Create the bot name
var bot = new irc.Client(config.server, config.botName, {
	channels: config.channels
});

Now you're setup is complete;  time to make things happen!

Bot Listeners and Responses

Once a configuration is created, the library is available, and the bot has been created, the possibilities are endless.  The majority of interactions will start with an event listener and a basic response:

// Listen for joins
bot.addListener("join", function(channel, who) {
	// Welcome them in!
	bot.say(channel, who + "...dude...welcome back!");
});

Whenever a user enters the room, they'll be greeted with the response above.  If I want to listen to each message and respond accordingly, I could add:

// Listen for any message, PM said user when he posts
bot.addListener("message", function(from, to, text, message) {
	bot.say(from, "¿Que?");
});

// Listen for any message, say to him/her in the room
bot.addListener("message", function(from, to, text, message) {
	bot.say(config.channels[0], "¿Public que?");
});

There are many more events to listen for too;  the IRC API is quite extensive.  In the case of the Mozilla bug bot I mentioned above, one would simply need to parse the message for a 6 digit number to trigger a bug detail lookup, then message the response when the desired information was retrieved. With these event listeners in place, you can use any other Node.js lib or custom code to perform any function you'd like.

Running the Bot

Running the bot is simple too -- simply open a new shell and execute:

node bot.js

Thanks to this awesome NodeJS IRC library and its incredibly easy to use API, I can cross off creating an IRC bot from my WebDev bucket list.  Better yet, I got to create the bot using JavaScript.  If you want to create a useful bot, or simply one to annoy people, give the IRC library a try!