IRC Hacks [Electronic resources] نسخه متنی

Hack 59 An Egg Timer

Create an IRC bot that can remind you to do
something after a set interval.

Some people spend far too long in front of
their computers using IRC. If you are one of those people, here is a
hack that may appeal to you. Never again will you forget to do
something important, because you'll be able to get
an IRC bot to remind you!

This hack shows how to create a simple IRC bot that sits in any
number of channels and responds to the !egg
command. After three minutes, the bot will remind you that your egg
is done, for this is how long it takes to boil the perfect egg.

Scheduling a task for later
execution is easy with Java. The java.util.Timer
class allows you to schedule tasks that extend
java.util.TimerTask. The Timer
class is scalable, so the bot should be perfectly capable of
scheduling thousands of tasks at the same time.
That's a lot of eggs.

9.3.1 The Code

You will need to create a special class called
EggTimerTask
that extends
TimerTask. When the egg is ready, the
run method in this class will be called. In the
run method, the bot must send a message to the
channel to tell the user that her egg is ready to eat. Instances of
this class therefore need to store a reference to the bot, channel,
and nickname of the user.

Create the file EggTimerTask.java:

import java.util.TimerTask;
public class EggTimerTask extends TimerTask {
private EggTimerBot bot;
private String nick;
private String channel;
public EggTimerTask(EggTimerBot bot, String nick, String channel) {
this.bot = bot;
this.nick = nick;
this.channel = channel;
}
public void run( ) {
bot.sendMessage(channel, nick + ": Your egg is ready!");
}
}

Writing the actual bot is rather straightforward, as all you need to
do is make it respond to messages that look like
"!egg". It needs to create a new
EggTimerTask and schedule it for running three
minutes later.

Create the file
EggTimerBot.java
:

import org.jibble.pircbot.*;
import java.util.Timer;
public class EggTimerBot extends PircBot {
public static final long DURATION = 3 * 60 * 1000;
private Timer timer = new Timer(true);
public EggTimerBot(String name) {
setName(name);
}
public void onMessage(String channel, String sender,
String login, String hostname, String message) {
if (message.trim( ).toLowerCase( ).equals("!egg")) {
sendMessage(channel, sender + ": I am timing your 3 minutes now...");
EggTimerTask timerTask = new EggTimerTask(this, sender, channel);
timer.schedule(timerTask, DURATION);
}
}
}

Finally, you just need a main method to start the bot and tell it to
connect to a server and join a channel. If you want, you can ask this
bot to join more than one channel, and it will still happily do its
job.

Save the following as
EggTimerBotMain.java
:

public class EggTimerBotMain {
public static void main(String[] args) throws Exception {
EggTimerBot bot = new EggTimerBot("eggcook");
bot.setVerbose(true);
bot.connect("irc.freenode.net");
bot.joinChannel("#irchacks");
}
}

9.3.2 Running the Hack

Compile the bot:

C:\java\EggTimerBot> javac -classpath .;pircbot.jar *.java

Run it like so:

C:\java\EggTimerBot> java -classpath .;pircbot.jar EggTimerBotMain

9.3.3 The Results

When someone issues the !egg command, the bot will
tell him when three minutes has elapsed, as shown in Figure 9-2.

Figure 9-2. The working egg timer

9.3.4 Hacking the Hack

Timing three minutes is fine if you're a fan of
boiled eggs, but not everything takes three minutes to cook. You
could generalize the bot so it is suitable for other purposes. Modify
the body of the onMessage method so it can accept
a new command, !timer
duration, where
duration is the number of seconds to wait
before alerting you:

message = message.trim( ).toLowerCase( );
if (message.equals("!egg")) {
sendMessage(channel, sender + ": I am timing your 3 minutes now...");
EggTimerTask timerTask = new EggTimerTask(this, sender, channel);
timer.schedule(timerTask, DURATION);
}
else if (message.startsWith("!timer ")) {
try {
int duration = Integer.parseInt(message.substring(7));
if (duration > 0) {
EggTimerTask timerTask = new EggTimerTask(this, sender, channel);
// Multiply the milliseconds by 1000 to get seconds.
timer.schedule(timerTask, duration * 1000);
}
}
catch (NumberFormatException e) {
// Do nothing.
}
}

You can now get the bot to time any period measured in seconds, for
example:

!timer  30 

would make the bot wait half a minute before telling you your
egg's ready. Of course, you may not be using it for
cooking eggs by this stage, so you may like to change the message
that is output by the EggTimerTask
class.