/*
* Copyright (C) 2013 Glyptodon LLC
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package org.glyptodon.guacamole.net.basic.websocket.jetty8;
import java.io.IOException;
import javax.servlet.http.HttpServletRequest;
import org.glyptodon.guacamole.GuacamoleException;
import org.glyptodon.guacamole.io.GuacamoleReader;
import org.glyptodon.guacamole.io.GuacamoleWriter;
import org.glyptodon.guacamole.net.GuacamoleTunnel;
import org.eclipse.jetty.websocket.WebSocket;
import org.eclipse.jetty.websocket.WebSocket.Connection;
import org.eclipse.jetty.websocket.WebSocketServlet;
import org.glyptodon.guacamole.GuacamoleClientException;
import org.glyptodon.guacamole.GuacamoleConnectionClosedException;
import org.glyptodon.guacamole.protocol.GuacamoleStatus;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A WebSocketServlet partial re-implementation of GuacamoleTunnelServlet.
*
* @author Michael Jumper
*/
public abstract class GuacamoleWebSocketTunnelServlet extends WebSocketServlet {
/**
* Logger for this class.
*/
private static final Logger logger = LoggerFactory.getLogger(GuacamoleWebSocketTunnelServlet.class);
/**
* The default, minimum buffer size for instructions.
*/
private static final int BUFFER_SIZE = 8192;
/**
* Sends the given status on the given WebSocket connection and closes the
* connection.
*
* @param connection The WebSocket connection to close.
* @param guac_status The status to send.
*/
public static void closeConnection(Connection connection,
GuacamoleStatus guac_status) {
connection.close(guac_status.getWebSocketCode(),
Integer.toString(guac_status.getGuacamoleStatusCode()));
}
@Override
public WebSocket doWebSocketConnect(HttpServletRequest request, String protocol) {
// Get tunnel
final GuacamoleTunnel tunnel;
try {
tunnel = doConnect(request);
}
catch (GuacamoleException e) {
logger.error("Creation of WebSocket tunnel to guacd failed: {}", e.getMessage());
logger.debug("Error connecting WebSocket tunnel.", e);
return null;
}
// Return new WebSocket which communicates through tunnel
return new WebSocket.OnTextMessage() {
@Override
public void onMessage(String string) {
GuacamoleWriter writer = tunnel.acquireWriter();
// Write message received
try {
writer.write(string.toCharArray());
}
catch (GuacamoleConnectionClosedException e) {
logger.debug("Connection to guacd closed.", e);
}
catch (GuacamoleException e) {
logger.debug("WebSocket tunnel write failed.", e);
}
tunnel.releaseWriter();
}
@Override
public void onOpen(final Connection connection) {
// Do not start connection if tunnel does not exist
if (tunnel == null) {
closeConnection(connection, GuacamoleStatus.RESOURCE_NOT_FOUND);
return;
}
Thread readThread = new Thread() {
@Override
public void run() {
StringBuilder buffer = new StringBuilder(BUFFER_SIZE);
GuacamoleReader reader = tunnel.acquireReader();
char[] readMessage;
try {
try {
// Attempt to read
while ((readMessage = reader.read()) != null) {
// Buffer message
buffer.append(readMessage);
// Flush if we expect to wait or buffer is getting full
if (!reader.available() || buffer.length() >= BUFFER_SIZE) {
connection.sendMessage(buffer.toString());
buffer.setLength(0);
}
}
// No more data
closeConnection(connection, GuacamoleStatus.SUCCESS);
}
// Catch any thrown guacamole exception and attempt
// to pass within the WebSocket connection, logging
// each error appropriately.
catch (GuacamoleClientException e) {
logger.info("WebSocket connection terminated: {}", e.getMessage());
logger.debug("WebSocket connection terminated due to client error.", e);
closeConnection(connection, e.getStatus());
}
catch (GuacamoleConnectionClosedException e) {
logger.debug("Connection to guacd closed.", e);
closeConnection(connection, GuacamoleStatus.SUCCESS);
}
catch (GuacamoleException e) {
logger.error("Connection to guacd terminated abnormally: {}", e.getMessage());
logger.debug("Internal error during connection to guacd.", e);
closeConnection(connection, e.getStatus());
}
}
catch (IOException e) {
logger.debug("WebSocket tunnel read failed due to I/O error.", e);
}
}
};
readThread.start();
}
@Override
public void onClose(int i, String string) {
try {
if (tunnel != null)
tunnel.close();
}
catch (GuacamoleException e) {
logger.debug("Unable to close connection to guacd.", e);
}
}
};
}
/**
* Called whenever the JavaScript Guacamole client makes a connection
* request. It it up to the implementor of this function to define what
* conditions must be met for a tunnel to be configured and returned as a
* result of this connection request (whether some sort of credentials must
* be specified, for example).
*
* @param request The HttpServletRequest associated with the connection
* request received. Any parameters specified along with
* the connection request can be read from this object.
* @return A newly constructed GuacamoleTunnel if successful,
* null otherwise.
* @throws GuacamoleException If an error occurs while constructing the
* GuacamoleTunnel, or if the conditions
* required for connection are not met.
*/
protected abstract GuacamoleTunnel doConnect(HttpServletRequest request)
throws GuacamoleException;
}