Netty RtspEncoder/Decoder issue

Question

To develop RtspClient(just message transaction, not playing video), I thought that I will use Netty, and I have created the classes as follow,(rtsp is creating toooo much problem to me, I don't know, is this because lag of knowledge? any-how...),

TestRtspClient.java

    public class TestRtspClient {

    private final String host;
    private final int port;

    public TestRtspClient(String host, int port) {
        this.host = host;
        this.port = port;       
    }

    public void start() throws Exception {

        EventLoopGroup group = new NioEventLoopGroup();

        try {

            Bootstrap bootstrap = new Bootstrap();

            bootstrap.group(group);
            bootstrap.channel(NioSocketChannel.class);
            bootstrap.handler(new TestRtspClientInitializer());

            Channel channel = bootstrap.connect(host, port).sync().channel();

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            //DESCRIBE rtsp://192.168.1.26:8554/nature.ts RTSP/1.0\r\nCSeq: 3\r\n\r\n
            while(true) {
                channel.write(br.readLine() + "\r\n");
                channel.flush();
            }

        } finally {
            group.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        new TestRtspClient("192.168.1.26", 8554).start();
    }   
}

and here is TestRtspClientInitializer.java

    public class TestRtspClientInitializer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel ch) throws Exception {

        ChannelPipeline pipe = ch.pipeline();

//      pipe.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
//      pipe.addLast("decoder", new StringDecoder());
//      pipe.addLast("encoder", new StringEncoder());

//      pipe.addLast("encoder", new RtspRequestEncoder());
//      pipe.addLast("decoder", new RtspResponseDecoder());

        pipe.addLast("encoder", new HttpRequestEncoder());
        pipe.addLast("decoder", new HttpResponseDecoder());

        pipe.addLast("handler", new TestRtspClientHandler());
    }
}

and here is TestRtspClientHandler.java

public class TestRtspClientHandler extends ChannelInboundMessageHandlerAdapter<HttpObject> {

      @Override
      public void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception {
              if(msg instanceof HttpResponse) {
                 System.out.println("Rtsp Response"); 
              } else if(msg instanceof HttpRequest) {
                 System.out.println("Rtsp Request"); 
              } else {
                 System.err.println("not supported format");
              }
       }

}

and I am using Live555MediaServer as RtspServer and Netty 4.0.0.CR3. When I am using DelimiterBasedFrameDecoder with stringdecoder and encoder its working fine, but If I use RtspRequest/Response encoder/decoder I am getting following warning, and no msg will be sent to L555.(also same with HttpReq/Resp encoder and decoder)

passing this as commandline arg in eclipse

DESCRIBE rtsp://192.168.1.26:8554/nature.ts RTSP/1.0\\r\\nCSeq: 3\\r\\n

Mar 25, 2014 6:45:28 PM io.netty.channel.DefaultChannelPipeline$ByteHeadHandler flush WARNING: Discarded 1 outbound message(s) that reached at the head of the pipeline. Please check your pipeline configuration.

Help me to fix this issue, and also explain me in-brief what is wrong in this code modules.

Thank You.

Answer 1

First of all, please upgrade to the latest Netty 4.0.x version.

Because you specified <String> when you extend ChannelInboundMessageHandlerAdapter in your TestRtspClientHandler , it will only receive a message whose type is String , which is not the case. You have to use HttpObject instead of String .