org.webbitserver.netty.FlashPolicyFileDecoder Maven / Gradle / Ivy

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package org.webbitserver.netty;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.handler.codec.frame.FrameDecoder;
import org.jboss.netty.util.CharsetUtil;

import java.util.concurrent.Executor;

/**
 * Checks the received {@link org.jboss.netty.buffer.ChannelBuffer
 * ChannelBuffer}s for Flash policy file requests.
 * 
 * 

 * If this decoder detects a Flash policy file request it adds a
 * {@link FlashPolicyFileHandler} to the
 * {@link org.jboss.netty.channel.ChannelPipeline ChannelPipeline} and removes
 * itself from the pipeline. If a Flash policy file request is not detected in
 * the first 23 bytes of the buffer, the decoder removes itself from the
 * pipeline.
 * 

 * 

 * 

 * This implementation is based on the
 * "replacing a decoder with another decoder in a pipeline" section of the
 * {@link org.jboss.netty.handler.codec.frame.FrameDecoder FrameDecoder}
 * documentation.
 * 
 */
public class FlashPolicyFileDecoder extends FrameDecoder {
    private static final ChannelBuffer FLASH_POLICY_REQUEST = ChannelBuffers
            .copiedBuffer("\0", CharsetUtil.US_ASCII);

    private final Executor executor;
    private final Thread.UncaughtExceptionHandler exceptionHandler;
    private final Thread.UncaughtExceptionHandler ioExceptionHandler;
    private final int publicPort;

    public FlashPolicyFileDecoder(Executor executor, Thread.UncaughtExceptionHandler exceptionHandler, Thread.UncaughtExceptionHandler ioExceptionHandler, int publicPort) {
        super(true);
        this.publicPort = publicPort;
        this.executor = executor;
        this.exceptionHandler = exceptionHandler;
        this.ioExceptionHandler = ioExceptionHandler;
    }

    @Override
    protected Object decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws Exception {

        // Will use the first 23 bytes to detect the policy file request.
        if (buffer.readableBytes() >= 23) {
            ChannelPipeline p = ctx.getPipeline();
            ChannelBuffer firstMessage = buffer.readBytes(23);

            if (FLASH_POLICY_REQUEST.equals(firstMessage)) {
                p.addAfter("flashpolicydecoder", "flashpolicyhandler",
                        new FlashPolicyFileHandler(executor, exceptionHandler, ioExceptionHandler, this.publicPort));
            }

            p.remove(this);

            if (buffer.readable()) {
                return new Object[]{firstMessage, buffer.readBytes(buffer.readableBytes())};
            } else {
                return firstMessage;
            }

        }

        // Forward the current buffer as is to handlers.
        return buffer.readBytes(buffer.readableBytes());

    }

}