NATIVE MESSAGING HOST

using System;
using System.IO;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace NativeMessagingHost
{
   class Program
   {
      public static void Main(string[] args)
      {
         JObject data;
         while ((data = Read()) != null)
         {
            var processed = ProcessMessage(data);
            Write(processed);
            if (processed == "exit")
            {
               return;
            }
         }
      }

      public static string ProcessMessage(JObject data)
      {
         var message = data["message"].Value<string>();
         switch (message)
         {
            case "test":
               return "testing!";
            case "exit":
               return "exit";
            default:
               return "echo: " + message;
         }
      }

      public static JObject Read()
      {
         var stdin = Console.OpenStandardInput();
         var length = 0;

         var lengthBytes = new byte[4];
         stdin.Read(lengthBytes, 0, 4);
         length = BitConverter.ToInt32(lengthBytes, 0);

         var buffer = new char[length];
         using (var reader = new StreamReader(stdin))
         {
            while (reader.Peek() >= 0)
            {
               reader.Read(buffer, 0, buffer.Length);
            }
         }

         return (JObject)JsonConvert.DeserializeObject<JObject>(new string(buffer))["data"];
      }

      public static void Write(JToken data)
      {
         var json = new JObject();
         json["data"] = data;

         var bytes = System.Text.Encoding.UTF8.GetBytes(json.ToString(Formatting.None));

         var stdout = Console.OpenStandardOutput();
         stdout.WriteByte((byte)((bytes.Length >> 0) & 0xFF));
         stdout.WriteByte((byte)((bytes.Length >> 8) & 0xFF));
         stdout.WriteByte((byte)((bytes.Length >> 16) & 0xFF));
         stdout.WriteByte((byte)((bytes.Length >> 24) & 0xFF));
         stdout.Write(bytes, 0, bytes.Length);
         stdout.Flush();
      }
   }
}