Package org.jvnet.glassfish.comms.clb.proxy.outbound

Source Code of org.jvnet.glassfish.comms.clb.proxy.outbound.DefaultCallBackHandler

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*
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* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License").  You
* may not use this file except in compliance with the License. You can obtain
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* file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
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package org.jvnet.glassfish.comms.clb.proxy.outbound;

import com.sun.grizzly.CallbackHandler;
import com.sun.grizzly.ConnectorHandler;
import com.sun.grizzly.Context;
import com.sun.grizzly.Context.OpType;
import com.sun.grizzly.Context.KeyRegistrationState;
import com.sun.grizzly.Controller;
import com.sun.grizzly.IOEvent;
import com.sun.grizzly.SelectorHandler;
import com.sun.grizzly.filter.ReadFilter;
import com.sun.grizzly.util.OutputWriter;
import com.sun.grizzly.util.SSLOutputWriter;
import com.sun.grizzly.util.WorkerThread;

import org.jvnet.glassfish.comms.clb.proxy.HttpProxy;
import org.jvnet.glassfish.comms.clb.proxy.ProxyRequestHandler;
import org.jvnet.glassfish.comms.clb.proxy.config.ProxyConfig;

import javax.net.ssl.SSLEngine;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.SocketChannel;

import java.util.logging.Level;
import java.util.logging.Logger;
import org.jvnet.glassfish.comms.clb.proxy.api.Endpoint;

/**
* CallBack handler to handle the responses coming from the backend. This can
* be reused only after calling refresh.
*
* @author
*/
public class DefaultCallBackHandler implements CallbackHandler<Context> {

    protected ConnectorHandler connectorHandler;
    protected Logger _logger = null;
    protected SelectionKey clientKey;
    protected SelectionKey serverKey;
    protected ReadFilter readFilter = new ReadFilter();
    protected ResponseHandler responseHandler = new ResponseHandler();
    protected boolean keepAlive = false;
    protected static ConnectionManager connectionManager =
            HttpProxy.getInstance().getConnectionManager();
    protected  SSLEngine sslEngine;
    protected   ByteBuffer  outputBB;
    protected boolean isSecure = false;
    boolean parsed = false;
    protected Endpoint endpoint = null;
    boolean inpool = true;
    private static int READ_ATTEMPTS = 2;
  
    /** Creates a new instance of DefaultCallBackHandler */
    public DefaultCallBackHandler(ConnectorHandler handler,
            ProxyRequestHandler reqHandler) {
        _logger = ProxyConfig.getInstance().getLogger();
        init(handler, reqHandler);
    }

    public void init(ConnectorHandler handler, ProxyRequestHandler reqHandler) {
        connectorHandler = handler;
        clientKey = reqHandler.getSelectionKey();
        keepAlive = reqHandler.getKeepAlive();
        sslEngine = reqHandler.getSSLEngine();
        outputBB = reqHandler.getOutputBB();
        isSecure = reqHandler.isSecure();
        responseHandler.recycle();
        readFilter.setReadAttempts(READ_ATTEMPTS);
        parsed = false;
        endpoint = reqHandler.getEndpoint();
        inpool = false;
     }

    public void refresh(ConnectorHandler handler,
            ProxyRequestHandler reqHandler) {
        init(handler, reqHandler);
        if (serverKey.isValid() &&
                (serverKey.interestOps() & SelectionKey.OP_READ) !=
                SelectionKey.OP_READ) {
            handler.getSelectorHandler().register(serverKey,
                    SelectionKey.OP_READ);
        }
    }

    public void onWrite(IOEvent<Context> ioEvent) {
        throw new IllegalStateException("Invalid state");
    }

    /*
     *  Utility method to print the message
     */
    private void dumpBuffer(ByteBuffer buf) {
        int pos = buf.position();
        int limit = buf.limit();
        StringBuffer buff = new StringBuffer(buf.limit());
        for (int i = 0; i < buf.limit(); i++) {
            buff.append((char) buf.get(i));
        }
        buf.position(pos);
        buf.limit(limit);
        _logger.log(Level.FINEST, buff.toString());
    }

    /**
     * Called when the connection has been established.
     */
    public void onConnect(IOEvent<Context> ioEvent) {
        serverKey = ioEvent.attachment().getSelectionKey();
        try {
            connectorHandler.finishConnect(serverKey);
        } catch (Exception e) {
            /*
             * Throw an exception so that the calling
             * thread knows that onConnect failed. There
             * is no other means to convey the failure.
             */
            _logger.log(Level.SEVERE, e.getMessage());
            ioEvent.attachment().getSelectorHandler().
                    getSelectionKeyHandler().cancel(serverKey);
            throw new RuntimeException(e);
        }
        ioEvent.attachment().getController().registerKey(
                serverKey, SelectionKey.OP_READ, Controller.Protocol.TCP);
       
        if (_logger.isLoggable(Level.FINEST)) {
            _logger.log(Level.FINEST, "clb.proxy.callback_serverkey" + serverKey);
            _logger.log(Level.FINEST, "clb.proxy.callback.clientkey" +
                    clientKey.channel());
            _logger.log(Level.FINEST, "clb.proxy.callback.server_channel" +
                    serverKey.channel());
        }
    }

    /*
     * This is required to ensure that the connect is invoked
     * on the same calling thread,
     */
    public boolean isRunInSeparateThread(OpType opType) {
        return opType != OpType.OP_CONNECT;
    }

    /*
     * A handler has to be cleaned if the connection is closed by the peer.
     */
    private void cleanFeBeHandler(SelectorHandler selectorhandler,
            SelectionKey key) {
        connectionManager.cleanUpHandler(connectorHandler, endpoint);
        selectorhandler.getSelectionKeyHandler().
                cancel(key);
    }

    /*
     * Utility method to read from channel. If read returns false, we have to
     * close this channel. We are using the ReadFilter here to read from
     * the channel.
     */
         
    private boolean readFromFeBeChannel(Context ctx) {
        boolean ret = true;
        try {
            /* Required because if we do not set this the read filter would
             * return false if 0 bytes are read and attempts exhausted.
             */
            ctx.setKeyRegistrationState(KeyRegistrationState.NONE);
            ret = readFilter.execute(ctx);
           
        } catch (Exception e) {
            _logger.log(Level.SEVERE,"Read Exception ", e);
            ret = false;
        }
        /*
         * If filter returns false we have to close the febe channel because
         * probably this is a half closed socket.
         */
        if (!ret) {
            cleanFeBeHandler(ctx.getSelectorHandler(),
                    ctx.getSelectionKey());
            if (!inpool){
                connectionManager.removeClientEndpoint(clientKey);
                connectionManager.cancelClientKey(clientKey);
            }
        }
        return ret;
    }

    /*
     * Method invoked when the read event is selected for this channel.
     */
    public void onRead(IOEvent<Context> ioEvent) {
        Context ctx = ioEvent.attachment();
        ByteBuffer byteBuffer = null;
        WorkerThread workerThread = (WorkerThread) Thread.currentThread();
        byteBuffer = workerThread.getByteBuffer();
        SelectionKey febeSelectionKey = ctx.getSelectionKey();       
        if (!readFromFeBeChannel(ctx)) {
            return;
       
        /*
         * Paranoid check to fail early.
         */
        if (byteBuffer.position() == 0 || responseHandler == null
                || clientKey == null ) {
            ctx.getSelectorHandler().register(febeSelectionKey,
                    SelectionKey.OP_READ);
            return;
        }
        /* Parsed is an instance variable whose value has to be preserved
         * until the lifecycle of the callback handler.
         */
        if (!parsed) {
            while (!responseHandler.parse(byteBuffer)) {
                if (_logger.isLoggable(Level.FINE)) {
                    _logger.log(Level.FINE,
                            "clb.proxy.callback_algorithm_parse_false");
                }
                if (!readFromFeBeChannel(ctx)) {
                    return;
                }
            }
            parsed = true;
        } else {
            byteBuffer.flip();
        }
        SocketChannel clientChannel = null;
        if (clientKey != null){
            clientChannel = (SocketChannel)clientKey.channel();
        }
       
        if (_logger.isLoggable(Level.FINEST)) {
            _logger.log(Level.FINEST, "clb.proxy.callback.algorithm_finished",
                    clientChannel.socket().getRemoteSocketAddress());
            _logger.log(Level.FINEST, "clb.proxy.callback_clientkey",
                    clientKey.channel());
            _logger.log(Level.FINEST, "clb.proxy.callback.server_channel",
                    ctx.getSelectionKey().channel());
            _logger.log(Level.FINEST, "Byte Buffer " + byteBuffer);
            try {
                dumpBuffer(byteBuffer);
            } catch (Exception e) {
                //ignore
            }
        }
       
        long byteswritten = 0;
        int iPos = byteBuffer.position();
        int iLimit = byteBuffer.limit();
        int bytesToBeWritten = byteBuffer.remaining();       
        boolean writeSuccess = true;
        /*
         * If we have the bytes ready write it to the client
         */
       
        if ((clientChannel != null) && (clientChannel.isConnected())) {
            try {
                if (isSecure) {
                    if (_logger.isLoggable(Level.FINEST)) {
                        _logger.log(Level.FINEST,
                                "clb.proxy.callback.ssl_writer",
                                clientChannel + " " + byteBuffer + " " +
                                outputBB + " " + sslEngine);
                    }
                    byteswritten = SSLOutputWriter.flushChannel(clientChannel,
                            byteBuffer, outputBB, sslEngine);
                } else {
                    byteswritten = OutputWriter.flushChannel(clientChannel,
                            byteBuffer);
                }
            } catch (Exception ioe) {
                /*
                 * If write fails then close client and update the response
                 * handler. We have to drop the response because we cannot send
                 * it through another channel.
                 */
                writeSuccess = false;
                responseHandler.updateBytesWritten(bytesToBeWritten);
                byteBuffer.position(iPos);
                byteBuffer.limit(iLimit);               
            }
            if (responseHandler.isTransferEncoding()) {
                if (_logger.isLoggable(Level.FINE)) {
                    _logger.log(Level.FINE, "Transfer encoding Byte buffer " +
                            byteBuffer);
                }
                /**
                 * It is quite inefficient to search for termination in the whole
                 * bytebuffer, Needs to be modified
                 */
                responseHandler.updateEnd((ByteBuffer) byteBuffer.flip());
            } else {
                responseHandler.updateBytesWritten(byteswritten);
            }

        } else {
            _logger.log(Level.SEVERE,
                    "clb.proxy.callback_client_channel_closed");
            writeSuccess = false;
        }
        if (byteBuffer != null) {
            byteBuffer.clear();
        }               
        boolean register = false;
        if (outputBB != null) {
            outputBB.clear();
       
        if (responseHandler.hasRemaining()) {
            /*
             * If write to client failed and there is still more data
             * to be read from the backend we cannot re-use the febe channel
             * anymore.
             */
            if (!writeSuccess) {
                cleanFeBeHandler(ctx.getSelectorHandler(),
                        febeSelectionKey);
                connectionManager.removeClientEndpoint(clientKey);
                connectionManager.cancelClientKey(clientKey);
            } else {
                register = true;
            }          
            if (_logger.isLoggable(Level.FINEST)) {
                _logger.log(Level.FINEST,
                        "clb.proxy.callback.algorithm_more_data",
                        clientChannel.socket().getRemoteSocketAddress());
            }
        } else {                        
            /* keep the key registered because it can be closed by the
             * peer when in the cache, when this happens the read will
             * will be invoked and we can close the channel. We dont have to
             * keep it registered when keep alive is disabled because we
             * can  be sure that the channel will not be closed. 
             */           
            register = true;
            // refactor
            if (!writeSuccess){
                /*
                 * Close only the client because we can re-use febe channel
                 */
                connectionManager.removeClientEndpoint(clientKey);
                connectionManager.cancelClientKey(clientKey);
            }    
           
            if (!keepAlive) {
                if (_logger.isLoggable(Level.FINEST)) {
                    _logger.log(Level.FINEST,
                            "clb.proxy.callback.algorithm_cancelled_key",
                            clientChannel.socket().getRemoteSocketAddress());
                }
                connectionManager.cancelClientKey(clientKey);
            } else {
                if (_logger.isLoggable(Level.FINEST)) {
                    _logger.log(Level.FINEST,
                            "clb.proxy.callback.algorithm_registered_key",
                            clientChannel.socket().getRemoteSocketAddress());
                }
                connectionManager.registerClientKey(clientKey);               
            }
           
            release();
        }
         if (register) {
            ctx.getSelectorHandler().register(febeSelectionKey,
                    SelectionKey.OP_READ);
        }
       
    }

    private void release() {
        try {           
            connectionManager.removeClientEndpoint(clientKey);
            connectionManager.releaseConnection(this.connectorHandler, endpoint);
            if (_logger.isLoggable(Level.FINEST)) {
                _logger.log(Level.FINEST,
                        "clb.proxy.callback.release");
            }
        } catch (Exception exception) {
            _logger.log(Level.SEVERE,
                    "clb.proxy.callback.release_error", exception);
        } finally {
            inpool = true;
        }

    }
}
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