NettyHttpServerSocketOptions.java

public class NettyHttpServerSocketOptions extends NettyServerSocketOptions {
  @Override
  public final Consumer<ChannelPipeline> pipelineConfigurer() {
    return new Consumer<ChannelPipeline>() {
      @Override
      public void accept(ChannelPipeline pipeline) {
        pipeline.addLast(new HttpRequestDecoder());
        pipeline.addLast(new HttpObjectAggregator(Integer.MAX_VALUE));
        pipeline.addLast(new HttpResponseEncoder());
      }
    };
  }
}

SimpleHttpServer.java

TcpServer<HttpRequest, HttpResponse> server = new TcpServerSpec<HttpRequest, HttpResponse>(NettyTcpServer.class)
  .env(env)
  .listen(port)
  .options(new NettyHttpServerSocketOptions())
  .consume(new Consumer<TcpConnection<HttpRequest, HttpResponse>>() {
    @Override
    public void accept(final TcpConnection<HttpRequest, HttpResponse> conn) {
      // Use the Stream API rather than consuming messages directly
      conn.in()
          .map(new Function<HttpRequest, HttpResponse>() {
            @Override
            public HttpResponse apply(HttpRequest req) {
              ByteBuf buf = Unpooled.copiedBuffer("Hello World!".getBytes());
              int len = buf.readableBytes();

              DefaultFullHttpResponse resp = new DefaultFullHttpResponse(
                  HttpVersion.HTTP_1_1,
                  HttpResponseStatus.OK,
                  buf
              );

              HttpHeaders hdrs = resp.headers();
              hdrs.set(HttpHeaders.Names.CONTENT_LENGTH, len);
              hdrs.set(HttpHeaders.Names.CONTENT_TYPE, "text/plain");
              hdrs.set(HttpHeaders.Names.CONNECTION, "Keep-Alive");
              // NOTE: This would be a fully-formed, "proper" HTTP 1.1 response 
              // if we added Date and Server headers.

              // If we're just writing the response, then we can return it from a Function.
              // We only need to send responses later if we're doing long work of some kind
              // like submitting a batch job to a worker queue.
              return resp;
            }
          })
          // the output of a connection is also a Consumer
          .consume(conn.out());
    }
  })
  .get();