Java tutorial
/** * Copyright 2012 Ronen Hamias, Anton Kharenko * * 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 io.scalecube.socketio.pipeline; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.List; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.MessageToMessageEncoder; import io.netty.handler.codec.http.HttpResponse; import io.netty.handler.codec.http.websocketx.TextWebSocketFrame; import io.netty.util.CharsetUtil; import io.netty.util.ReferenceCounted; import io.scalecube.socketio.TransportType; import io.scalecube.socketio.packets.IPacket; import io.scalecube.socketio.packets.Packet; import io.scalecube.socketio.packets.PacketsFrame; import io.scalecube.socketio.serialization.PacketEncoder; import io.scalecube.socketio.serialization.PacketFramer; /** * <p> * This class encodes Socket.IO messages they're sent. The structure of a * message is as follows: * </p> * * <p> * {@code [message type] ':' [message id ('+')] ':' [message endpoint] (':' [message data])} * </p> * * <p> * The message type is a single digit integer. The message id is an incremental * integer, required for ACKs (can be ommitted). If the message id is followed * by a +, the ACK is not handled by socket.io, but by the user instead. * Socket.IO has built-in support for multiple channels of communication (which * we call "multiple sockets"). Each socket is identified by an endpoint (can be * omitted). * </p> * * @author Ronen Hamias, Anton Kharenko * */ @ChannelHandler.Sharable public class PacketEncoderHandler extends MessageToMessageEncoder<Object> { private final static String JSONP_TEMPLATE = "io.j[%s]('%s');"; private final Logger log = LoggerFactory.getLogger(getClass()); @Override protected void encode(ChannelHandlerContext ctx, Object msg, List<Object> out) throws Exception { if (msg instanceof IPacket) { IPacket packet = (IPacket) msg; if (log.isDebugEnabled()) log.debug("Sending packet: {} to channel: {}", msg, ctx.channel()); ByteBuf encodedPacket = encodePacket(packet); if (log.isDebugEnabled()) log.debug("Encoded packet: {}", encodedPacket); TransportType transportType = packet.getTransportType(); if (transportType == TransportType.WEBSOCKET || transportType == TransportType.FLASHSOCKET) { out.add(new TextWebSocketFrame(encodedPacket)); } else if (transportType == TransportType.XHR_POLLING) { out.add(PipelineUtils.createHttpResponse(packet.getOrigin(), encodedPacket, false)); } else if (transportType == TransportType.JSONP_POLLING) { String jsonpIndexParam = (packet.getJsonpIndexParam() != null) ? packet.getJsonpIndexParam() : "0"; String encodedStringPacket = encodedPacket.toString(CharsetUtil.UTF_8); encodedPacket.release(); String encodedJsonpPacket = String.format(JSONP_TEMPLATE, jsonpIndexParam, encodedStringPacket); HttpResponse httpResponse = PipelineUtils.createHttpResponse(packet.getOrigin(), PipelineUtils.copiedBuffer(ctx.alloc(), encodedJsonpPacket), true); httpResponse.headers().add("X-XSS-Protection", "0"); out.add(httpResponse); } else { throw new UnsupportedTransportTypeException(transportType); } } else { if (msg instanceof ReferenceCounted) { ((ReferenceCounted) msg).retain(); } out.add(msg); } } private ByteBuf encodePacket(final IPacket msg) throws Exception { if (msg instanceof PacketsFrame) { return PacketFramer.encodePacketsFrame((PacketsFrame) msg); } else if (msg instanceof Packet) { return PacketEncoder.encodePacket((Packet) msg); } else { throw new UnsupportedPacketTypeException(msg); } } }