org.royaldev.enterprise.proxy.ProxyFrontendHandler.java Source code

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Here is the source code for org.royaldev.enterprise.proxy.ProxyFrontendHandler.java

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/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package org.royaldev.enterprise.proxy;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelOption;

public class ProxyFrontendHandler extends ChannelHandlerAdapter {

    private final String remoteHost;
    private final int remotePort;

    private volatile Channel outboundChannel;

    public ProxyFrontendHandler(String remoteHost, int remotePort) {
        this.remoteHost = remoteHost;
        this.remotePort = remotePort;
    }

    /**
     * Closes the specified channel after all queued write requests are flushed.
     */
    static void closeOnFlush(Channel ch) {
        if (ch.isActive())
            ch.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        final Channel inboundChannel = ctx.channel();

        // Start the connection attempt.
        Bootstrap b = new Bootstrap();
        b.group(inboundChannel.eventLoop()).channel(ctx.channel().getClass())
                .handler(new ProxyBackendHandler(inboundChannel)).option(ChannelOption.AUTO_READ, false);
        ChannelFuture f = b.connect(remoteHost, remotePort);
        outboundChannel = f.channel();
        f.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                if (future.isSuccess()) {
                    // connection complete start to read first data
                    inboundChannel.read();
                } else {
                    // Close the connection if the connection attempt has failed.
                    inboundChannel.close();
                }
            }
        });
    }

    @Override
    public void channelRead(final ChannelHandlerContext ctx, Object msg) throws Exception {
        if (outboundChannel.isActive()) {
            outboundChannel.writeAndFlush(msg).addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    if (future.isSuccess()) {
                        // was able to flush out data, start to read the next chunk
                        ctx.channel().read();
                    } else {
                        future.channel().close();
                    }
                }
            });
        }
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        if (outboundChannel != null) {
            closeOnFlush(outboundChannel);
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        closeOnFlush(ctx.channel());
    }
}