private void writeResponse(Channel channel, HttpRequest request, String message, String client) {
    String contentType = "text/plain";
    if (client != null && (client.equals("web") || client.equals("bluej"))) {
      // convert to HTML
      message = message.replaceAll("\n", "<br>\n");
      contentType = "text/html";
    }
    // Convert the response content to a ChannelBuffer.
    ByteBuf buf = copiedBuffer(message, CharsetUtil.UTF_8);

    // Decide whether to close the connection or not.
    boolean close =
        HttpHeaders.Values.CLOSE.equalsIgnoreCase(request.headers().get(CONNECTION))
            || request.getProtocolVersion().equals(HttpVersion.HTTP_1_0)
                && !HttpHeaders.Values.KEEP_ALIVE.equalsIgnoreCase(
                    request.headers().get(CONNECTION));

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

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

    // 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);
    }
  }
  /**
   * Flush the response contents to the output channel
   *
   * @param channel Channel to be used
   */
  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 =
        HttpHeaders.Values.CLOSE.equalsIgnoreCase(request.headers().get(CONNECTION))
            || request.getProtocolVersion().equals(HttpVersion.HTTP_1_0)
                && !HttpHeaders.Values.KEEP_ALIVE.equalsIgnoreCase(
                    request.headers().get(CONNECTION));

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

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

    try {
      // 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);
      }
    } catch (Exception e) {
      logger.error("{}", e);
    }
  }