/*
* Copyright 1999-2011 Alibaba Group.
*
* Licensed 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 com.alibaba.dubbo.remoting.telnet.codec;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerFactory;
import com.alibaba.dubbo.common.utils.StringUtils;
import com.alibaba.dubbo.remoting.Channel;
import com.alibaba.dubbo.remoting.RemotingException;
import com.alibaba.dubbo.remoting.buffer.ChannelBuffer;
import com.alibaba.dubbo.remoting.transport.codec.TransportCodec;
/**
* TelnetCodec
*
* @author heyman
* @author william.liangf
* @author chao.liuc
*/
public class TelnetCodec extends TransportCodec {
private static final Logger logger = LoggerFactory.getLogger(TelnetCodec.class);
private static final String HISTORY_LIST_KEY = "telnet.history.list";
private static final String HISTORY_INDEX_KEY = "telnet.history.index";
private static final byte[] UP = new byte[] {27, 91, 65};
private static final byte[] DOWN = new byte[] {27, 91, 66};
private static final List<?> ENTER = Arrays.asList(new Object[] { new byte[] { '\r', '\n' } /* Windows Enter */, new byte[] { '\n' } /* Linux Enter */ });
private static final List<?> EXIT = Arrays.asList(new Object[] { new byte[] { 3 } /* Windows Ctrl+C */, new byte[] { -1, -12, -1, -3, 6 } /* Linux Ctrl+C */, new byte[] { -1, -19, -1, -3, 6 } /* Linux Pause */ });
public void encode(Channel channel, ChannelBuffer buffer, Object message) throws IOException {
if (message instanceof String) {
if (isClientSide(channel)) {
message = message + "\r\n";
}
byte[] msgData = ((String) message).getBytes(getCharset(channel).name());
buffer.writeBytes(msgData);
} else {
super.encode(channel, buffer, message);
}
}
public Object decode(Channel channel, ChannelBuffer buffer) throws IOException {
int readable = buffer.readableBytes();
byte[] message = new byte[readable];
buffer.readBytes(message);
return decode(channel, buffer, readable, message);
}
@SuppressWarnings("unchecked")
protected Object decode(Channel channel, ChannelBuffer buffer, int readable, byte[] message) throws IOException {
if (isClientSide(channel)) {
return toString(message, getCharset(channel));
}
checkPayload(channel, readable);
if (message == null || message.length == 0) {
return DecodeResult.NEED_MORE_INPUT;
}
if (message[message.length - 1] == '\b') { // Windows backspace echo
try {
boolean doublechar = message.length >= 3 && message[message.length - 3] < 0; // double byte char
channel.send(new String(doublechar ? new byte[] {32, 32, 8, 8} : new byte[] {32, 8}, getCharset(channel).name()));
} catch (RemotingException e) {
throw new IOException(StringUtils.toString(e));
}
return DecodeResult.NEED_MORE_INPUT;
}
for (Object command : EXIT) {
if (isEquals(message, (byte[]) command)) {
if (logger.isInfoEnabled()) {
logger.info(new Exception("Close channel " + channel + " on exit command: " + Arrays.toString((byte[])command)));
}
channel.close();
return null;
}
}
boolean up = endsWith(message, UP);
boolean down = endsWith(message, DOWN);
if (up || down) {
LinkedList<String> history = (LinkedList<String>) channel.getAttribute(HISTORY_LIST_KEY);
if (history == null || history.size() == 0) {
return DecodeResult.NEED_MORE_INPUT;
}
Integer index = (Integer) channel.getAttribute(HISTORY_INDEX_KEY);
Integer old = index;
if (index == null) {
index = history.size() - 1;
} else {
if (up) {
index = index - 1;
if (index < 0) {
index = history.size() - 1;
}
} else {
index = index + 1;
if (index > history.size() - 1) {
index = 0;
}
}
}
if (old == null || ! old.equals(index)) {
channel.setAttribute(HISTORY_INDEX_KEY, index);
String value = history.get(index);
if (old != null && old >= 0 && old < history.size()) {
String ov = history.get(old);
StringBuilder buf = new StringBuilder();
for (int i = 0; i < ov.length(); i ++) {
buf.append("\b");
}
for (int i = 0; i < ov.length(); i ++) {
buf.append(" ");
}
for (int i = 0; i < ov.length(); i ++) {
buf.append("\b");
}
value = buf.toString() + value;
}
try {
channel.send(value);
} catch (RemotingException e) {
throw new IOException(StringUtils.toString(e));
}
}
return DecodeResult.NEED_MORE_INPUT;
}
for (Object command : EXIT) {
if (isEquals(message, (byte[]) command)) {
if (logger.isInfoEnabled()) {
logger.info(new Exception("Close channel " + channel + " on exit command " + command));
}
channel.close();
return null;
}
}
byte[] enter = null;
for (Object command : ENTER) {
if (endsWith(message, (byte[]) command)) {
enter = (byte[]) command;
break;
}
}
if (enter == null) {
return DecodeResult.NEED_MORE_INPUT;
}
LinkedList<String> history = (LinkedList<String>) channel.getAttribute(HISTORY_LIST_KEY);
Integer index = (Integer) channel.getAttribute(HISTORY_INDEX_KEY);
channel.removeAttribute(HISTORY_INDEX_KEY);
if (history != null && history.size() > 0 && index != null && index >= 0 && index < history.size()) {
String value = history.get(index);
if (value != null) {
byte[] b1 = value.getBytes();
if (message != null && message.length > 0) {
byte[] b2 = new byte[b1.length + message.length];
System.arraycopy(b1, 0, b2, 0, b1.length);
System.arraycopy(message, 0, b2, b1.length, message.length);
message = b2;
} else {
message = b1;
}
}
}
String result = toString(message, getCharset(channel));
if (result != null && result.trim().length() > 0) {
if (history == null) {
history = new LinkedList<String>();
channel.setAttribute(HISTORY_LIST_KEY, history);
}
if (history.size() == 0) {
history.addLast(result);
} else if (! result.equals(history.getLast())) {
history.remove(result);
history.addLast(result);
if (history.size() > 10) {
history.removeFirst();
}
}
}
return result;
}
private static Charset getCharset(Channel channel) {
if (channel != null) {
Object attribute = channel.getAttribute(Constants.CHARSET_KEY);
if (attribute instanceof String) {
try {
return Charset.forName((String) attribute);
} catch (Throwable t) {
logger.warn(t.getMessage(), t);
}
} else if (attribute instanceof Charset) {
return (Charset) attribute;
}
URL url = channel.getUrl();
if (url != null) {
String parameter = url.getParameter(Constants.CHARSET_KEY);
if (parameter != null && parameter.length() > 0) {
try {
return Charset.forName(parameter);
} catch (Throwable t) {
logger.warn(t.getMessage(), t);
}
}
}
}
try {
return Charset.forName("GBK");
} catch (Throwable t) {
logger.warn(t.getMessage(), t);
}
return Charset.defaultCharset();
}
private static String toString(byte[] message, Charset charset) throws UnsupportedEncodingException {
byte[] copy = new byte[message.length];
int index = 0;
for (int i = 0; i < message.length; i ++) {
byte b = message[i] ;
if (b == '\b') { // backspace
if (index > 0) {
index --;
}
if (i > 2 && message[i - 2] < 0) { // double byte char
if (index > 0) {
index --;
}
}
} else if (b == 27) { // escape
if (i < message.length - 4 && message[i + 4] == 126) {
i = i + 4;
} else if (i < message.length - 3 && message[i + 3] == 126) {
i = i + 3;
} else if (i < message.length - 2) {
i = i + 2;
}
} else if (b == -1 && i < message.length - 2
&& (message[i + 1] == -3 || message[i + 1] == -5)) { // handshake
i = i + 2;
} else {
copy[index ++] = message[i];
}
}
if (index == 0) {
return "";
}
return new String(copy, 0, index, charset.name()).trim();
}
private static boolean isEquals(byte[] message, byte[] command) throws IOException {
return message.length == command.length && endsWith(message, command);
}
private static boolean endsWith(byte[] message, byte[] command) throws IOException {
if (message.length < command.length) {
return false;
}
int offset = message.length - command.length;
for (int i = command.length - 1; i >= 0 ; i --) {
if (message[offset + i] != command[i]) {
return false;
}
}
return true;
}
}