Java tutorial
/* * Copyright 2019 Anton Tananaev (anton@traccar.org) * * Licensed 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.traccar.handler; import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBufUtil; import io.netty.channel.ChannelDuplexHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelPromise; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.traccar.NetworkMessage; import java.net.InetSocketAddress; import java.net.SocketAddress; public class StandardLoggingHandler extends ChannelDuplexHandler { private static final Logger LOGGER = LoggerFactory.getLogger(StandardLoggingHandler.class); private final String protocol; public StandardLoggingHandler(String protocol) { this.protocol = protocol; } @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { log(ctx, false, msg); super.channelRead(ctx, msg); } @Override public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception { log(ctx, true, msg); super.write(ctx, msg, promise); } public void log(ChannelHandlerContext ctx, boolean downstream, Object o) { if (o instanceof NetworkMessage) { NetworkMessage networkMessage = (NetworkMessage) o; if (networkMessage.getMessage() instanceof ByteBuf) { log(ctx, downstream, networkMessage.getRemoteAddress(), (ByteBuf) networkMessage.getMessage()); } } else if (o instanceof ByteBuf) { log(ctx, downstream, ctx.channel().remoteAddress(), (ByteBuf) o); } } public void log(ChannelHandlerContext ctx, boolean downstream, SocketAddress remoteAddress, ByteBuf buf) { StringBuilder message = new StringBuilder(); message.append("[").append(ctx.channel().id().asShortText()).append(": "); message.append(protocol); if (downstream) { message.append(" > "); } else { message.append(" < "); } if (remoteAddress instanceof InetSocketAddress) { message.append(((InetSocketAddress) remoteAddress).getHostString()); } else { message.append("unknown"); } message.append("]"); message.append(" HEX: "); message.append(ByteBufUtil.hexDump(buf)); LOGGER.info(message.toString()); } }