Java tutorial
/* * Copyright (C) 2004-2015 L2J Unity * * This file is part of L2J Unity. * * L2J Unity is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * L2J Unity is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.l2junity.gameserver.network.telnet; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandler.Sharable; import io.netty.channel.ChannelHandlerAdapter; import io.netty.channel.ChannelHandlerContext; import io.netty.util.AttributeKey; import java.util.ArrayList; import java.util.Date; import java.util.List; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.l2junity.Config; /** * @author UnAfraid */ @Sharable public class TelnetServerHandler extends ChannelHandlerAdapter { private static final Pattern COMMAND_ARGS_PATTERN = Pattern.compile("\"([^\"]*)\"|([^\\s]+)"); private static final AttributeKey<Boolean> AUTHORIZED = AttributeKey.valueOf(TelnetServerHandler.class, "AUTHORIZED"); private String tryHandleCommand(ChannelHandlerContext ctx, String command, String[] args) { final ITelnetCommand cmd = TelnetServer.getInstance().getCommand(command); if (cmd == null) { return "Unknown command." + System.lineSeparator(); } String response = cmd.handle(ctx, args); if (response == null) { response = "Usage:" + System.lineSeparator() + cmd.getUsage() + System.lineSeparator(); } return response; } @Override public void channelActive(ChannelHandlerContext ctx) { String ip = ctx.channel().remoteAddress().toString(); ip = ip.substring(1, ip.lastIndexOf(':')); // Trim out /127.0.0.1:14013 if (!Config.TELNET_HOSTS.contains(ip)) { final ChannelFuture future = ctx .write("Your ip: " + ip + " is not allowed to connect." + System.lineSeparator()); future.addListener(ChannelFutureListener.CLOSE); ctx.flush(); return; } // Send greeting for a new connection. ctx.write("Welcome to the L2J Unity telnet session." + System.lineSeparator()); ctx.write("It is " + new Date() + " now." + System.lineSeparator()); ctx.write("Please enter your password:" + System.lineSeparator()); if (!Config.TELNET_PASSWORD.isEmpty()) { // Ask password ctx.write("Password:"); ctx.attr(AUTHORIZED).set(Boolean.FALSE); } else { ctx.write("Type 'help' to see all available commands." + System.lineSeparator()); ctx.attr(AUTHORIZED).set(Boolean.TRUE); } ctx.flush(); } @Override public void channelRead(ChannelHandlerContext ctx, Object msg) { // Cast to a String first. // We know it is a String because we put some codec in TelnetPipelineFactory. String request = (String) msg; // Generate and write a response. String response = null; boolean close = false; if (Boolean.FALSE.equals(ctx.attr(AUTHORIZED).get())) { if (Config.TELNET_PASSWORD.equals(request)) { ctx.attr(AUTHORIZED).set(Boolean.TRUE); request = ""; } else { response = "Wrong password!" + System.lineSeparator(); close = true; } } if (Boolean.TRUE.equals(ctx.attr(AUTHORIZED).get())) { if (request.isEmpty()) { response = "Type 'help' to see all available commands." + System.lineSeparator(); } else if (request.toLowerCase().equals("exit")) { response = "Have a good day!" + System.lineSeparator(); close = true; } else { final Matcher m = COMMAND_ARGS_PATTERN.matcher(request); if (m.find()) { String command = m.group(); List<String> args = new ArrayList<>(); String arg; while (m.find()) { arg = m.group(1); if (arg == null) { arg = m.group(0); } args.add(arg); } response = tryHandleCommand(ctx, command, args.toArray(new String[args.size()])); if (!response.endsWith(System.lineSeparator())) { response += System.lineSeparator(); } } } } // We do not need to write a ChannelBuffer here. // We know the encoder inserted at TelnetPipelineFactory will do the conversion. final ChannelFuture future = ctx.write(response); // Close the connection after sending 'Have a good day!' // if the client has sent 'exit'. if (close) { future.addListener(ChannelFutureListener.CLOSE); } } @Override public void channelReadComplete(ChannelHandlerContext ctx) { ctx.flush(); } }