private void writeResponse(Channel channel) {
    // Convert the response content to a ChannelBuffer.
    ByteBuf buf = copiedBuffer(responseContent.toString(), CharsetUtil.UTF_8);
    responseContent.setLength(0);

    // Decide whether to close the connection or not.
    boolean close =
        request.headers().contains(HttpHeaderNames.CONNECTION, HttpHeaderValues.CLOSE, true)
            || request.protocolVersion().equals(HttpVersion.HTTP_1_0)
                && !request
                    .headers()
                    .contains(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE, true);

    // Build the response object.
    FullHttpResponse response =
        new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, buf);
    response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain; charset=UTF-8");

    if (!close) {
      // There's no need to add 'Content-Length' header
      // if this is the last response.
      response.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, buf.readableBytes());
    }

    Set<Cookie> cookies;
    String value = request.headers().getAndConvert(HttpHeaderNames.COOKIE);
    if (value == null) {
      cookies = Collections.emptySet();
    } else {
      cookies = ServerCookieDecoder.STRICT.decode(value);
    }
    if (!cookies.isEmpty()) {
      // Reset the cookies if necessary.
      for (Cookie cookie : cookies) {
        response
            .headers()
            .add(HttpHeaderNames.SET_COOKIE, ServerCookieEncoder.STRICT.encode(cookie));
      }
    }
    // Write the response.
    ChannelFuture future = channel.writeAndFlush(response);
    // Close the connection after the write operation is done if necessary.
    if (close) {
      future.addListener(ChannelFutureListener.CLOSE);
    }
  }
  @Override
  public void messageReceived(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
    if (msg instanceof HttpRequest) {
      HttpRequest request = this.request = (HttpRequest) msg;
      URI uri = new URI(request.uri());
      if (!uri.getPath().startsWith("/form")) {
        // Write Menu
        writeMenu(ctx);
        return;
      }
      responseContent.setLength(0);
      responseContent.append("WELCOME TO THE WILD WILD WEB SERVER\r\n");
      responseContent.append("===================================\r\n");

      responseContent.append("VERSION: " + request.protocolVersion().text() + "\r\n");

      responseContent.append("REQUEST_URI: " + request.uri() + "\r\n\r\n");
      responseContent.append("\r\n\r\n");

      // new getMethod
      for (Entry<CharSequence, CharSequence> entry : request.headers()) {
        responseContent.append("HEADER: " + entry.getKey() + '=' + entry.getValue() + "\r\n");
      }
      responseContent.append("\r\n\r\n");

      // new getMethod
      Set<Cookie> cookies;
      String value = request.headers().getAndConvert(HttpHeaderNames.COOKIE);
      if (value == null) {
        cookies = Collections.emptySet();
      } else {
        cookies = ServerCookieDecoder.STRICT.decode(value);
      }
      for (Cookie cookie : cookies) {
        responseContent.append("COOKIE: " + cookie + "\r\n");
      }
      responseContent.append("\r\n\r\n");

      QueryStringDecoder decoderQuery = new QueryStringDecoder(request.uri());
      Map<String, List<String>> uriAttributes = decoderQuery.parameters();
      for (Entry<String, List<String>> attr : uriAttributes.entrySet()) {
        for (String attrVal : attr.getValue()) {
          responseContent.append("URI: " + attr.getKey() + '=' + attrVal + "\r\n");
        }
      }
      responseContent.append("\r\n\r\n");

      // if GET Method: should not try to create a HttpPostRequestDecoder
      if (request.method().equals(HttpMethod.GET)) {
        // GET Method: should not try to create a HttpPostRequestDecoder
        // So stop here
        responseContent.append("\r\n\r\nEND OF GET CONTENT\r\n");
        // Not now: LastHttpContent will be sent writeResponse(ctx.channel());
        return;
      }
      try {
        decoder = new HttpPostRequestDecoder(factory, request);
      } catch (ErrorDataDecoderException e1) {
        e1.printStackTrace();
        responseContent.append(e1.getMessage());
        writeResponse(ctx.channel());
        ctx.channel().close();
        return;
      }

      readingChunks = HttpHeaderUtil.isTransferEncodingChunked(request);
      responseContent.append("Is Chunked: " + readingChunks + "\r\n");
      responseContent.append("IsMultipart: " + decoder.isMultipart() + "\r\n");
      if (readingChunks) {
        // Chunk version
        responseContent.append("Chunks: ");
        readingChunks = true;
      }
    }

    // check if the decoder was constructed before
    // if not it handles the form get
    if (decoder != null) {
      if (msg instanceof HttpContent) {
        // New chunk is received
        HttpContent chunk = (HttpContent) msg;
        try {
          decoder.offer(chunk);
        } catch (ErrorDataDecoderException e1) {
          e1.printStackTrace();
          responseContent.append(e1.getMessage());
          writeResponse(ctx.channel());
          ctx.channel().close();
          return;
        }
        responseContent.append('o');
        // example of reading chunk by chunk (minimize memory usage due to
        // Factory)
        readHttpDataChunkByChunk();
        // example of reading only if at the end
        if (chunk instanceof LastHttpContent) {
          writeResponse(ctx.channel());
          readingChunks = false;

          reset();
        }
      }
    } else {
      writeResponse(ctx.channel());
    }
  }
  private void writeMenu(ChannelHandlerContext ctx) {
    // print several HTML forms
    // Convert the response content to a ChannelBuffer.
    responseContent.setLength(0);

    // create Pseudo Menu
    responseContent.append("<html>");
    responseContent.append("<head>");
    responseContent.append("<title>Netty Test Form</title>\r\n");
    responseContent.append("</head>\r\n");
    responseContent.append("<body bgcolor=white><style>td{font-size: 12pt;}</style>");

    responseContent.append("<table border=\"0\">");
    responseContent.append("<tr>");
    responseContent.append("<td>");
    responseContent.append("<h1>Netty Test Form</h1>");
    responseContent.append("Choose one FORM");
    responseContent.append("</td>");
    responseContent.append("</tr>");
    responseContent.append("</table>\r\n");

    // GET
    responseContent.append("<CENTER>GET FORM<HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");
    responseContent.append("<FORM ACTION=\"/formget\" METHOD=\"GET\">");
    responseContent.append("<input type=hidden name=getform value=\"GET\">");
    responseContent.append("<table border=\"0\">");
    responseContent.append(
        "<tr><td>Fill with value: <br> <input type=text name=\"info\" size=10></td></tr>");
    responseContent.append(
        "<tr><td>Fill with value: <br> <input type=text name=\"secondinfo\" size=20>");
    responseContent.append(
        "<tr><td>Fill with value: <br> <textarea name=\"thirdinfo\" cols=40 rows=10></textarea>");
    responseContent.append("</td></tr>");
    responseContent.append(
        "<tr><td><INPUT TYPE=\"submit\" NAME=\"Send\" VALUE=\"Send\"></INPUT></td>");
    responseContent.append(
        "<td><INPUT TYPE=\"reset\" NAME=\"Clear\" VALUE=\"Clear\" ></INPUT></td></tr>");
    responseContent.append("</table></FORM>\r\n");
    responseContent.append("<CENTER><HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");

    // POST
    responseContent.append("<CENTER>POST FORM<HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");
    responseContent.append("<FORM ACTION=\"/formpost\" METHOD=\"POST\">");
    responseContent.append("<input type=hidden name=getform value=\"POST\">");
    responseContent.append("<table border=\"0\">");
    responseContent.append(
        "<tr><td>Fill with value: <br> <input type=text name=\"info\" size=10></td></tr>");
    responseContent.append(
        "<tr><td>Fill with value: <br> <input type=text name=\"secondinfo\" size=20>");
    responseContent.append(
        "<tr><td>Fill with value: <br> <textarea name=\"thirdinfo\" cols=40 rows=10></textarea>");
    responseContent.append(
        "<tr><td>Fill with file (only file name will be transmitted): <br> "
            + "<input type=file name=\"myfile\">");
    responseContent.append("</td></tr>");
    responseContent.append(
        "<tr><td><INPUT TYPE=\"submit\" NAME=\"Send\" VALUE=\"Send\"></INPUT></td>");
    responseContent.append(
        "<td><INPUT TYPE=\"reset\" NAME=\"Clear\" VALUE=\"Clear\" ></INPUT></td></tr>");
    responseContent.append("</table></FORM>\r\n");
    responseContent.append("<CENTER><HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");

    // POST with enctype="multipart/form-data"
    responseContent.append(
        "<CENTER>POST MULTIPART FORM<HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");
    responseContent.append(
        "<FORM ACTION=\"/formpostmultipart\" ENCTYPE=\"multipart/form-data\" METHOD=\"POST\">");
    responseContent.append("<input type=hidden name=getform value=\"POST\">");
    responseContent.append("<table border=\"0\">");
    responseContent.append(
        "<tr><td>Fill with value: <br> <input type=text name=\"info\" size=10></td></tr>");
    responseContent.append(
        "<tr><td>Fill with value: <br> <input type=text name=\"secondinfo\" size=20>");
    responseContent.append(
        "<tr><td>Fill with value: <br> <textarea name=\"thirdinfo\" cols=40 rows=10></textarea>");
    responseContent.append("<tr><td>Fill with file: <br> <input type=file name=\"myfile\">");
    responseContent.append("</td></tr>");
    responseContent.append(
        "<tr><td><INPUT TYPE=\"submit\" NAME=\"Send\" VALUE=\"Send\"></INPUT></td>");
    responseContent.append(
        "<td><INPUT TYPE=\"reset\" NAME=\"Clear\" VALUE=\"Clear\" ></INPUT></td></tr>");
    responseContent.append("</table></FORM>\r\n");
    responseContent.append("<CENTER><HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");

    responseContent.append("</body>");
    responseContent.append("</html>");

    ByteBuf buf = copiedBuffer(responseContent.toString(), CharsetUtil.UTF_8);
    // Build the response object.
    FullHttpResponse response =
        new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, buf);

    response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html; charset=UTF-8");
    response.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, buf.readableBytes());

    // Write the response.
    ctx.channel().writeAndFlush(response);
  }