Protocol Buffer Challenge

Question

I am developing an application that uses the protocol buffer as a serializer . My application will be a client to a server. The requirement is that before sending the protobuf data I have to prepend the size of the protobuf data with 4 bytes. I am using Netty as my socket library. I have used the in-built protocolbuffer encoder and decoder of netty but I am still not getting the right result. This is the code I am running: Pipeline code

public class SmpPipelineFactory implements ChannelPipelineFactory {

    private final Logger logger = LoggerFactory.getLogger(getClass());

    /**
     * 
     */
    public SmpPipelineFactory() {
    }

    @Override
    public ChannelPipeline getPipeline() throws Exception {
        ChannelPipeline p = pipeline();

        // Add Decoders
        p.addLast("frameDecoder", new ProtobufVarint32FrameDecoder());      
        //p.addLast("frameDecoder",  new LengthFieldBasedFrameDecoder(1048576, 0, 4, 0, 4));        
        p.addLast("protobufDecoder", new ProtobufDecoder(Pdu.getDefaultInstance()));

        // Add encoders
        p.addLast("frameEncoder", new ProtobufVarint32LengthFieldPrepender());
        //p.addLast("frameEncoder", new LengthFieldPrepender(4));
        p.addLast("protobufEncoder", new ProtobufEncoder());

        p.addLast("handler", new SmpChannelConnector());

        return p;
    }

}

Any help will help Thank you.

pjklauser pjklauser · Accepted Answer · 2013-03-09T16:27:43

you need to explain a bit more about what is not working for you. If i look at the code in the protobuf RPC java library (https://code.google.com/p/protobuf-rpc-pro/ ) the class is DuplexTcpClientPipelineFactory or DuplexTcpServerPipelineFactory, which is basically the same code as your's and it "works". Maybe the protobuf-rpc-pro library can already do what you need.

public ChannelPipeline getPipeline() throws Exception {
    ChannelPipeline p = pipeline();

    RpcSSLContext ssl = bootstrap.getSslContext();
    if ( ssl != null ) {
            p.addLast(Handler.SSL, new SslHandler(ssl.createClientEngine()) );
    }

    p.addLast(Handler.FRAME_DECODER, new ProtobufVarint32FrameDecoder());
    p.addLast(Handler.PROTOBUF_DECODER, new ProtobufDecoder(DuplexProtocol.WirePayload.getDefaultInstance(),bootstrap.getExtensionRegistry()));

    p.addLast(Handler.FRAME_ENCODER, new ProtobufVarint32LengthFieldPrepender());
    p.addLast(Handler.PROTOBUF_ENCODER, new ProtobufEncoder());

    // the connectResponseHandler is swapped after the client connection
    // handshake with the RpcClient for the Channel
    p.addLast(Handler.CLIENT_CONNECT, new ClientConnectResponseHandler());

    return p;
}

is your server a netty server , or just a netty client?

Protocol Buffer Challenge

2 Answers