net.sourceforge.entrainer.socket.PortUnificationHandler.java Source code

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Here is the source code for net.sourceforge.entrainer.socket.PortUnificationHandler.java

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/*
 * Copyright (C) 2008 - 2015 Burton Alexander
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 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 General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * 
 */
package net.sourceforge.entrainer.socket;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.http.HttpRequestDecoder;
import io.netty.handler.codec.http.HttpResponseEncoder;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

import java.util.List;

// TODO: Auto-generated Javadoc
/**
 * The Class PortUnificationHandler.
 */
public class PortUnificationHandler extends ByteToMessageDecoder {

    private NettyConnectionHandler nettyConnectionHandler;
    private WebSocketHandler webSocketHandler;

    /**
     * Instantiates a new port unification handler.
     *
     * @param nettyConnectionHandler
     *          the netty connection handler
     * @param webSocketHandler
     *          the web socket handler
     */
    public PortUnificationHandler(NettyConnectionHandler nettyConnectionHandler,
            WebSocketHandler webSocketHandler) {
        this.nettyConnectionHandler = nettyConnectionHandler;
        this.webSocketHandler = webSocketHandler;
    }

    /*
     * (non-Javadoc)
     * 
     * @see io.netty.handler.codec.ByteToMessageDecoder#decode(io.netty.channel.
     * ChannelHandlerContext, io.netty.buffer.ByteBuf, java.util.List)
     */
    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
        // Will use the first five bytes to detect a protocol.
        if (in.readableBytes() < 5) {
            return;
        }

        final int magic1 = in.getUnsignedByte(in.readerIndex());
        final int magic2 = in.getUnsignedByte(in.readerIndex() + 1);
        if (isHttp(magic1, magic2)) {
            switchToWebSockets(ctx);
        } else {
            switchToJava(ctx);
        }
    }

    private static boolean isHttp(int magic1, int magic2) {
        return
        //@formatter:off
        magic1 == 'G' && magic2 == 'E' || // GET
                magic1 == 'P' && magic2 == 'O' || // POST
                magic1 == 'P' && magic2 == 'U' || // PUT
                magic1 == 'H' && magic2 == 'E' || // HEAD
                magic1 == 'O' && magic2 == 'P' || // OPTIONS
                magic1 == 'P' && magic2 == 'A' || // PATCH
                magic1 == 'D' && magic2 == 'E' || // DELETE
                magic1 == 'T' && magic2 == 'R' || // TRACE
                magic1 == 'C' && magic2 == 'O'; // CONNECT
        //@formatter:on
    }

    private void switchToWebSockets(ChannelHandlerContext ctx) throws Exception {
        ChannelPipeline pipeline = ctx.pipeline();

        pipeline.addLast("decoder", new HttpRequestDecoder());
        pipeline.addLast("encoder", new HttpResponseEncoder());
        pipeline.addLast("handler", webSocketHandler);
        webSocketHandler.channelActive(ctx);

        pipeline.remove(this);
    }

    private void switchToJava(ChannelHandlerContext ctx) throws Exception {
        ChannelPipeline pipeline = ctx.pipeline();

        pipeline.addLast(new LengthFieldBasedFrameDecoder(10000, 0, 4, 0, 4));
        pipeline.addLast(new StringDecoder());
        pipeline.addLast(new LengthFieldPrepender(4));
        pipeline.addLast(new StringEncoder());
        pipeline.addLast(nettyConnectionHandler);
        nettyConnectionHandler.channelActive(ctx);

        pipeline.remove(this);
    }
}