proxyService.ProxyFrontendHandler.java Source code

Introduction

Here is the source code for proxyService.ProxyFrontendHandler.java

Source

/*
 * 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 proxyService;

import node.Node;
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.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelOption;

public class ProxyFrontendHandler extends ChannelInboundHandlerAdapter {
    // Changed the ChannelHandlerAdapter to ChannelInboundHandlerAdapter

    private final Node node;

    private volatile Channel outboundChannel;

    public ProxyFrontendHandler(Node node) {
        this.node = node;
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        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(node.getIp(), node.getPort());
        System.out.println(this + " tunneling traffic to " + node.getIp() + ":" + node.getPort());
        outboundChannel = f.channel();
        f.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) {
                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) {
        if (outboundChannel.isActive()) {
            outboundChannel.writeAndFlush(msg).addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture future) {
                    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) {
        if (outboundChannel != null) {
            closeOnFlush(outboundChannel);
        }
    }

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

    /**
     * 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);
        }
    }
}