IRC bot, Node.js v0.6, 2011-12-15 Read and write to both irc and file. Two-way communication.

gistfile1.js

var util = require('util'),
	net = require('net');
	fs = require('fs');
	vm = require('vm');
	repl = require('repl');

var socket = new net.Socket();
    socket.setNoDelay(true);
    socket.setEncoding('ascii');

var buffer = {
    b: new Buffer(4096),
    size: 0
};

var textFile = '';

var channel = '#someChannel';

var logfile = 'C:\\irc_chatt_bot.txt';

fs.readFile(logfile, 'ascii', function (err, data) {
  if (err) throw err;
  textFile = data.replace(/\r/g, '').split('\n');
});

fs.watch(logfile, function (event, filename) {
  console.log('event is: ' + event);
  if (filename) {
    console.log('filename provided: ' + filename);

    // find new lines
    fs.readFile(logfile, 'ascii', function (err, data) {
        if (err) return;
  //if (err) throw err;
  	comp(data.replace(/\r/g, '').split('\n'));

});
  } else {
    console.log('filename not provided');
  }
});

function comp(n) {
	var clone = n.slice(0);
	for(var i = textFile.length; i--; ) {
		var index = n.indexOf(textFile[i]);
		if (index > -1) {
			n.splice(index, 1);
		}
	}
	for(var i = 0; i < n.length; i++) {
		//console.log('new' + n[i]);
        if (n[i].length > 0) {
		  send("PRIVMSG " + sanitize(channel) + " :\x01ACTION " + sanitize(n[i]) + "\x01");
            
        }
	}
	textFile = clone;
}

function send(data) {
	if(!data || data.length == 0) {
		console.log("ERROR tried to send no data");
		return;
	} else if (data.length > 510) {
        console.log("ERROR tried to send data > 510 chars in length: " + data);
        return;
    }
    socket.write(data + '\r\n', 'ascii', function () {
        console.log("-> " + data);
    });
}

socket.on('data', function (data) {
    data = data.replace('\r', '');
    var newlineIdx;
    while ((newlineIdx = data.indexOf('\n')) > -1) {
        if (buffer.size > 0) {
            data = buffer.b.toString('ascii', 0, buffer.size) + data;
            newlineIdx += buffer.size;
            buffer.size = 0;
        }
        handle(data.substr(0, newlineIdx));
        data = data.slice(newlineIdx + 1);
    }
    if (data.length > 0) {
        buffer.b.write(data, buffer.size, 'ascii');
        buffer.size += data.length;
    }
});

function handle(data) {
    console.log("<- " + data);
    match = /^PING :(.+)/i.exec(data);
    if (match) {
    	send("PONG :" + match[1]);
    }
    
    if (data.indexOf('Welcome to the QuakeNet IRC Network') > -1) {
		send("JOIN :" + sanitize(channel));
    }

    var replyTo = null;
    if (data.indexOf('PRIVMSG') > -1) {
        var dest = (/^:([^!]+)!.*PRIVMSG ([^ ]+) /i).exec(data);
        match = /PRIVMSG [^ ]+ :say (.*)/i.exec(data);
        if (match) {
        	console.log(dest[1] + ': ' + match[1]);
			textFile.push(dest[1] + ': ' + match[1]);
        	//writeStream.write('\r\n' + dest[1] + ': ' + match[1]);
        	fs.open(logfile, 'a', 666, function( e, id ) {
			  fs.write( id, '\r\n' + dest[1] + ': ' + match[1], null, 'ascii', function(){
			    fs.close(id, function(){
			      console.log('file closed');
			      //send("PRIVMSG " + sanitize(channel) + " :\x01ACTION " + sanitize(match[1]) + "\x01");
			    });
			  });
			});


        }

    }
}

function sanitize(data) {
    if (!data) {
		return data;
	}
	/* Note:
	 * 0x00 (null character) is invalid
	 * 0x01 signals a CTCP message, which we shouldn't ever need to do
	 * 0x02 is bold in mIRC (and thus other GUI clients)
	 * 0x03 precedes a color code in mIRC (and thus other GUI clients)
	 * 0x04 thru 0x19 are invalid control codes, except for:
	 * 0x16 is "reverse" (swaps fg and bg colors) in mIRC
	 */
    return data.replace(/\n/g, "\\n").replace(/\r/g, "\\r").replace(/[^\x02-\x03|\x16|\x20-\x7e]/g, "");
}

function connect(host, port, nickname, username, realname) {
    var port = port || 6667;
    socket.connect(port, host, function () {
        send('NICK ' + sanitize(nickname));
        send('USER ' + sanitize(username) + ' tolmoon tolsun :' + sanitize(realname));
    });
}

connect('se.quakenet.org', 6667, 'somenickname', 'someusername', 'somerealname');
repl.start();