Java tutorial
/* * Copyright 2012 The Netty Project * * The Netty Project licenses this file to you under the Apache License, * version 2.0 (the "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. */ package me.huzorro.gateway.telnet; import java.net.InetAddress; import java.net.InetSocketAddress; import java.util.ArrayList; import java.util.Arrays; import java.util.Date; import java.util.List; import me.huzorro.gateway.DefaultCommandService; import me.huzorro.gateway.DefaultServerSessionConfigFactory; import me.huzorro.gateway.DefaultServerSessionFactory; import me.huzorro.gateway.Session; import me.huzorro.gateway.SessionConfig; import org.apache.commons.lang.StringUtils; import org.jboss.netty.channel.ChannelFuture; import org.jboss.netty.channel.ChannelFutureListener; import org.jboss.netty.channel.ChannelHandlerContext; import org.jboss.netty.channel.ChannelStateEvent; import org.jboss.netty.channel.ExceptionEvent; import org.jboss.netty.channel.MessageEvent; import org.jboss.netty.channel.SimpleChannelUpstreamHandler; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Handles a server-side channel. */ public class TelnetServerHandler extends SimpleChannelUpstreamHandler { private static final Logger logger = LoggerFactory.getLogger(TelnetServerHandler.class); private boolean loggedin; private short trylogin; private DefaultServerSessionFactory<Session> sessionFactory; private DefaultServerSessionConfigFactory<SessionConfig> sessionConfigFactory; /** * @param sessionFactory * @param sessionConfigFactory */ public TelnetServerHandler(DefaultServerSessionFactory<Session> sessionFactory, DefaultServerSessionConfigFactory<SessionConfig> sessionConfigFactory) { this.sessionFactory = sessionFactory; this.sessionConfigFactory = sessionConfigFactory; } @Override public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { // Send greeting for a new connection. e.getChannel().write("Welcome to " + InetAddress.getLocalHost().getHostName() + "!\r\n"); e.getChannel().write("It is " + new Date() + " now.\r\n"); e.getChannel().write("login:"); } @Override public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception { // Cast to a String first. // We know it is a String because we put some codec in TelnetPipelineFactory. String request = (String) e.getMessage(); // Generate and write a response. String response; boolean close = false; if (request.length() == 0) { response = "Please type something.\r\n"; } else if (request.toLowerCase().equals("bye")) { response = "Have a good day!\r\n"; close = true; } else { response = "Did you say '" + request + "'?\r\n"; } if (!loggedin) { ++trylogin; if (trylogin > 3) { response = "login failed\r\n"; close = true; } else { String[] auth = request.split("@"); if (auth.length != 3) response = "login:"; if (auth.length == 3) { SessionConfig config = sessionConfigFactory.setHost( ((InetSocketAddress) ctx.getChannel().getRemoteAddress()).getAddress().getHostAddress()) .setUser(auth[0]).setVersion(Short.valueOf(auth[2])).create(); if (config == null || !config.getPasswd().equals(auth[1])) { response = "login:"; } else { sessionFactory.setChannel(ctx.getChannel()); sessionFactory.setConfig(config); Session session = sessionFactory.create(); if (session != null) { ctx.getChannel().setAttachment(session); session.getLoginFuture().setSuccess(); response = "login success\r\n"; loggedin = true; } else { response = "out of the max number of connections"; close = true; } } } } } else { List<String> list = new ArrayList<String>(Arrays.asList(StringUtils.split(request))); List<String> result = null; if (list.remove("help")) result = DefaultCommandService.help((String[]) list.toArray(new String[list.size()])); if (list.remove("start")) result = DefaultCommandService.start((String[]) list.toArray(new String[list.size()])); if (list.remove("stop")) result = DefaultCommandService.stop((String[]) list.toArray(new String[list.size()])); if (list.remove("status")) result = DefaultCommandService.status((String[]) list.toArray(new String[list.size()])); if (list.remove("kick")) result = DefaultCommandService.kick((String[]) list.toArray(new String[list.size()])); if (list.remove("clear")) result = DefaultCommandService.clear((String[]) list.toArray(new String[list.size()])); if (list.remove("bye")) result = DefaultCommandService.bye((String[]) list.toArray(new String[list.size()])); if (list.remove("shutdown")) result = DefaultCommandService.shutdown((String[]) list.toArray(new String[list.size()])); if (result != null) { for (String info : result) { response += info; response += "\r\n"; } } else { response = "command not found\r\n"; } } // We do not need to write a ChannelBuffer here. // We know the encoder inserted at TelnetPipelineFactory will do the conversion. ChannelFuture future = e.getChannel().write(response); // Close the connection after sending 'Have a good day!' // if the client has sent 'bye'. if (close) { future.addListener(ChannelFutureListener.CLOSE); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) { logger.error("Unexpected exception from downstream. {}", e.getCause()); e.getChannel().close(); } }