FlashBridgePlugIn.java

//	---------------------------------------------------------------------------
//	jWebSocket - FlashBridge Plug-In
//	Copyright (c) 2010 Innotrade GmbH (http://jWebSocket.org)
//	---------------------------------------------------------------------------
//	This program is free software; you can redistribute it and/or modify it
//	under the terms of the GNU Lesser General Public License as published by the
//	Free Software Foundation; either version 3 of the License, or (at your
//	option) any later version.
//	This program 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 Lesser General Public License 
//  for more details.
//	You should have received a copy of the GNU Lesser General Public License along
//	with this program; if not, see <http://www.gnu.org/licenses/lgpl.html>.
//	---------------------------------------------------------------------------
package org.jwebsocket.plugins.flashbridge;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;
import org.apache.log4j.Logger;
import org.jwebsocket.api.PluginConfiguration;
import org.jwebsocket.api.WebSocketEngine;
import org.jwebsocket.logging.Logging;
import org.jwebsocket.plugins.TokenPlugIn;

/**
 * This plug-in processes the policy-file-request from the browser side flash
 * plug-in. This makes jWebSocket cross-browser-compatible.
 * 
 * @author aschulze
 */
public class FlashBridgePlugIn extends TokenPlugIn {

  private static Logger mLog = Logging.getLogger(FlashBridgePlugIn.class);
  private ServerSocket mServerSocket = null;
  private int mListenerPort = 843;
  private boolean mIsRunning = false;
  private int mEngineInstanceCount = 0;
  private BridgeProcess mBridgeProcess = null;
  private Thread mBridgeThread = null;

  public FlashBridgePlugIn() {
    this(null);
  }

  public FlashBridgePlugIn(PluginConfiguration configuration) {
    super(configuration);
    if (mLog.isDebugEnabled()) {
      mLog.debug("Starting FlashBridge...");
    }
    try {
      mServerSocket = new ServerSocket(mListenerPort);

      mBridgeProcess = new BridgeProcess(this);
      mBridgeThread = new Thread(mBridgeProcess);
      mBridgeThread.start();
      if (mLog.isInfoEnabled()) {
        mLog.info("FlashBridge started.");
      }
    } catch (IOException ex) {
      mLog.error("FlashBridge could not be started: " + ex.getMessage());
    }
  }

  private class BridgeProcess implements Runnable {

    private final FlashBridgePlugIn mPlugIn;

    /**
     * creates the server socket bridgeProcess for new incoming socket
     * connections.
     * 
     * @param aPlugIn
     */
    public BridgeProcess(FlashBridgePlugIn aPlugIn) {
      this.mPlugIn = aPlugIn;
    }

    @Override
    public void run() {

      if (mLog.isDebugEnabled()) {
        mLog.debug("Starting FlashBridge process...");
      }
      mIsRunning = true;
      while (mIsRunning) {
        try {
          // accept is blocking so here is no need
          // to put any sleeps into the loop
          if (mLog.isDebugEnabled()) {
            mLog.debug("Waiting on flash policy-file-request on port " + mServerSocket.getLocalPort() + "...");
          }
          Socket clientSocket = mServerSocket.accept();
          if (mLog.isDebugEnabled()) {
            mLog.debug("Client connected...");
          }
          try {
            // clientSocket.setSoTimeout(TIMEOUT);
            InputStream lIS = clientSocket.getInputStream();
            OutputStream lOS = clientSocket.getOutputStream();
            byte[] ba = new byte[1024];
            String lLine = "";
            boolean lFoundPolicyFileRequest = false;
            int lLen = 0;
            while (lLen >= 0 && !lFoundPolicyFileRequest) {
              lLen = lIS.read(ba);
              if (lLen > 0) {
                lLine += new String(ba, 0, lLen, "US-ASCII");
              }
              if (mLog.isDebugEnabled()) {
                mLog.debug("Received " + lLine + "...");
              }
              lFoundPolicyFileRequest = lLine.indexOf("policy-file-request") >= 0; // "<policy-file-request/>"
            }
            if (lFoundPolicyFileRequest) {
              if (mLog.isDebugEnabled()) {
                mLog.debug("Answering on flash policy-file-request (" + lLine + ")...");
              }
              lOS.write(("<cross-domain-policy>" + "<allow-access-from domain=\"*\" to-ports=\"*\" />" + "</cross-domain-policy>").getBytes());
              lOS.flush();
            } else {
              mLog.warn("Received invalid policy-file-request (" + lLine + ")...");
            }
          } catch (UnsupportedEncodingException ex) {
            mLog.error("(encoding) " + ex.getClass().getSimpleName() + ": " + ex.getMessage());
          } catch (IOException ex) {
            mLog.error("(io) " + ex.getClass().getSimpleName() + ": " + ex.getMessage());
          } catch (Exception ex) {
            mLog.error("(other) " + ex.getClass().getSimpleName() + ": " + ex.getMessage());
          }

          clientSocket.close();
          if (mLog.isDebugEnabled()) {
            mLog.debug("Client disconnected...");
          }
        } catch (Exception ex) {
          mIsRunning = false;
          mLog.error("Socket state: " + ex.getMessage());
        }
      }
      if (mLog.isDebugEnabled()) {
        mLog.debug("FlashBridge process stopped.");
      }
    }
  }

  @Override
  public void engineStarted(WebSocketEngine aEngine) {
    if (mLog.isDebugEnabled()) {
      mLog.debug("Engine '" + aEngine.getId() + "' started.");
    }
    // every time an engine starts increment counter
    mEngineInstanceCount++;
  }

  @Override
  public void engineStopped(WebSocketEngine aEngine) {
    if (mLog.isDebugEnabled()) {
      mLog.debug("Engine '" + aEngine.getId() + "' stopped.");
    }
    // every time an engine starts decrement counter
    mEngineInstanceCount--;
    // when last engine stopped also stop the FlashBridge
    if (mEngineInstanceCount <= 0) {
      super.engineStopped(aEngine);

      mIsRunning = false;
      long lStarted = new Date().getTime();

      try {
        // when done, close server socket
        // closing the server socket should lead to an exception
        // at accept in the bridgeProcess thread which terminates the
        // bridgeProcess
        if (mLog.isDebugEnabled()) {
          mLog.debug("Closing FlashBridge server socket...");
        }
        mServerSocket.close();
        if (mLog.isDebugEnabled()) {
          mLog.debug("Closed FlashBridge server socket.");
        }
      } catch (Exception ex) {
        mLog.error("(accept) " + ex.getClass().getSimpleName() + ": " + ex.getMessage());
      }

      try {
        mBridgeThread.join(10000);
      } catch (Exception ex) {
        mLog.error(ex.getClass().getSimpleName() + ": " + ex.getMessage());
      }
      if (mLog.isDebugEnabled()) {
        long lDuration = new Date().getTime() - lStarted;
        if (mBridgeThread.isAlive()) {
          mLog.warn("FlashBridge did not stopped after " + lDuration + "ms.");
        } else {
          mLog.debug("FlashBridge stopped after " + lDuration + "ms.");
        }
      }
    }
  }
}