/*
 * Copyright 2015 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 io.netty.handler.codec.protobuf;

import com.google.protobuf.nano.CodedOutputByteBufferNano;
import com.google.protobuf.nano.MessageNano;

import java.util.List;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.MessageToMessageEncoder;

Encodes the requested Google Protocol Buffers MessageNano into a ByteBuf. A typical setup for TCP/IP would be:
ChannelPipeline pipeline = ...; // Decoders pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(1048576, 0, 4, 0, 4)); pipeline.addLast("protobufDecoder", new ProtobufDecoderNano(MyMessage.getDefaultInstance())); // Encoder pipeline.addLast("frameEncoder", new LengthFieldPrepender(4)); pipeline.addLast("protobufEncoder", new ProtobufEncoderNano()); 
and then you can use a MyMessage instead of a ByteBuf as a message:
void channelRead(ChannelHandlerContext ctx, Object msg) { MyMessage req = (MyMessage) msg; MyMessage res = MyMessage.newBuilder().setText( "Did you say '" + req.getText() + "'?").build(); ch.write(res); } 
/** * Encodes the requested <a href="https://github.com/google/protobuf">Google * Protocol Buffers</a> {@link MessageNano} into a * {@link ByteBuf}. A typical setup for TCP/IP would be: * <pre> * {@link ChannelPipeline} pipeline = ...; * * // Decoders * pipeline.addLast("frameDecoder", * new {@link LengthFieldBasedFrameDecoder}(1048576, 0, 4, 0, 4)); * pipeline.addLast("protobufDecoder", * new {@link ProtobufDecoderNano}(MyMessage.getDefaultInstance())); * * // Encoder * pipeline.addLast("frameEncoder", new {@link LengthFieldPrepender}(4)); * pipeline.addLast("protobufEncoder", new {@link ProtobufEncoderNano}()); * </pre> * and then you can use a {@code MyMessage} instead of a {@link ByteBuf} * as a message: * <pre> * void channelRead({@link ChannelHandlerContext} ctx, Object msg) { * MyMessage req = (MyMessage) msg; * MyMessage res = MyMessage.newBuilder().setText( * "Did you say '" + req.getText() + "'?").build(); * ch.write(res); * } * </pre> */
@ChannelHandler.Sharable public class ProtobufEncoderNano extends MessageToMessageEncoder<MessageNano> { @Override protected void encode( ChannelHandlerContext ctx, MessageNano msg, List<Object> out) throws Exception { final int size = msg.getSerializedSize(); final ByteBuf buffer = ctx.alloc().heapBuffer(size, size); final byte[] array = buffer.array(); CodedOutputByteBufferNano cobbn = CodedOutputByteBufferNano.newInstance(array, buffer.arrayOffset(), buffer.capacity()); msg.writeTo(cobbn); buffer.writerIndex(size); out.add(buffer); } }