IRC Hacks [Electronic resources] نسخه متنی

Hack 60 A Trivia Bot

Turn an IRC bot into an automated quiz show
host. Compete with your friends to be first to answer each
question.

If
your channel ever seems to lack excitement, you can rev up the
enjoyment factor by introducing a trivia bot
that asks questions and waits for someone to respond with the correct
answer. Most trivia bots ask a single question and wait for someone
to give the correct answer. When the correct answer has been given,
the bot will ask another question.

This hack will show you how to make a basic trivia bot that stores
all of its questions and answers in a text file. More advanced trivia
bots can let you store the total scores for each user and may even
have time limits for each question.

9.4.1 The Code

To make
your trivia bot easy to extend, you should create a
Question class, so each question (and answer) can
be stored in a Question object. The
Question class also provides an
isCorrect method, so you can see if a candidate
answer is correct.

Create a file called Question.java:

public class Question {
private String question;
private String answer;
public Question(String question, String answer) {
this.question = question;
this.answer = answer;
}
public String toString( ) {
return question;
}
public String getAnswer( ) {
return answer;
}
public boolean isCorrect(String a) {
return answer.equalsIgnoreCase(a);
}
}

The TriviaBot class will be used to maintain a
collection of Question objects. Each time a new
question is asked, it will be chosen randomly from this collection.
As soon as the trivia bot joins a channel, it will ask a question.

Whenever someone sends a message to the channel, the trivia bot will
check to see if it matches the answer for the current question. If
the answer is correct, the trivia bot will announce the sender of
that message as being the winner.

This trivia bot will also allow users to say the
"clue" command. If anybody
says "clue" in the channel, the
trivia bot will respond by showing how many letters are in the
answer. It does this by replacing each letter in the answer with a
* character and sending it to the channel. So if
the correct answer is "Internet Relay
Chat," the bot will send the following to the
channel:

<Jibbler> clue
<TriviaBot> Clue: ******** ***** ****

This class extends PircBot to connect to IRC and
uses the Random class in the
java.util package to generate
random question numbers.

Create a file called
TriviaBot.java:

import org.jibble.pircbot.*;
import java.util.*;
public class TriviaBot extends PircBot {
private Question currentQuestion = null;
private ArrayList questions = new ArrayList( );
private static Random rand = new Random( );
public TriviaBot(String name) {
setName(name);
}
public void addQuestion(Question question) {
questions.add(question);
}
public void onJoin(String channel, String sender,
String login, String hostname) {
if (sender.equals(getNick( ))) {
setNextQuestion(channel);
}
}
public void onMessage(String channel, String sender, String login,
String hostname, String message) {
message = message.toLowerCase( ).trim( );
if (currentQuestion.isCorrect(message)) {
sendMessage(channel, sender + " is the winner, with the correct"
+ "answer of" + currentQuestion.getAnswer( ));
setNextQuestion(channel);
}
else if (message.equalsIgnoreCase("clue")) {
String clue = currentQuestion.getAnswer( );
clue = clue.replaceAll("[^\\ ]", "*");
sendMessage(channel, "Clue: " + clue);
}
}
private void setNextQuestion(String channel) {
currentQuestion = (Question) questions.get(rand.nextInt(questions.size( )));
sendMessage(channel, "Next question: " + currentQuestion);
}
}

The TriviaBot class uses an
ArrayList to store each
Question object. New questions can be added to the
bot with the addQuestion method. The
setNextQuestion method is used to pick a random
question and announce it to the channel.

The onJoin method is overridden and will be called
whenever the bot joins a channel. The bot will then ask the first
randomly picked question.

The onMessage method is overridden and will be
called whenever someone sends a message to the channel. If the
message matches the correct answer for the current question, the bot
will announce that the sender won and it will then pose the next
question and carry on as before. If anybody sends the
"clue" command, the bot will send
the clue to the channel.

9.4.2 Making Questions

This bot will be near to useless
without a large bundle of questions to ask. For now though, you can
just make up a few questions to test the bot, then add more later.

Each line of the text file will contain a question and an answer. The
| character is used to separate each question and
its answer.

Create a file called quiz.txt and add some
questions:

What is the square root of 81?|9
What does IRC stand for?|Internet Relay Chat
What is "bot" short for?|robot

To make the bot turn each line of this file into a Question object,
you must parse the contents before the bot connects to a server. You
can add this little bit of code to the main method, which
instantiates the bot.

Create
TriviaBotMain.java:

import java.io.*;
public class TriviaBotMain {
public static void main(String[] args) throws Exception {
TriviaBot bot = new TriviaBot("TriviaBot");
// Read the questions from the file and add them to the bot.
BufferedReader reader = new BufferedReader(
new FileReader("./quiz.txt"));
String line;
while ((line = reader.readLine( )) != null) {
String[] tokens = line.split("\\|");
if (tokens.length == 2) {
Question question = new Question(tokens[0], tokens[1]);
bot.addQuestion(question);
}
}
bot.setVerbose(true);
bot.connect("irc.freenode.net");
bot.joinChannel("#irchacks");
}
}

9.4.3 Running the Hack

Compile the hack like so:

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

Run the bot like so:

C:\java\TriviaBot> java -classpath .;pircbot.jar TriviaBotMain

The bot will then start up.

9.4.4 The Results

When the bot starts up, it will read the questions from
quiz.txt, connect to the server, and join the
channel #irchacks, as shown in Figure 9-3.

Figure 9-3. TriviaBot running in #irchacks

Note that without modification, this bot is suitable only for use in
a single channel. This is because it stores the current question in a
single field (currentQuestion), while multiple
channel support would entail having a different variable for each
channel. One way to make it suitable for use in multiple channels is
to replace this simple variable with a HashMap, which is indexed by
the channel name. This approach is implemented in the WelcomeBot
[Hack #64] .