Hi, I am trying to implement file transfer from android to pc. The android client made in unity (c#) and pc server made in visual studio (c#).

when I sending file in loop by 3x1000Byte parts, i'm getting zero bytes came from nowhere in output log.

(its not the case that the connection is closed and server reads 0 bytes...)

as u can see on the screenshot - file is transferring good till 4460(dec) byte, then those zero bytes then resuming with correct bytes.

if someone knows where from those zero bytes came from, please help..

I doubt it will help, but here is the

server part:

 static void receivMediaFile(int partSize)
 {
     NetworkStream _ns = tcpClient.GetStream();

     byte[] longB = new byte[8];
     _ns.Read(longB, 0, 8);
     long fileLength = BitConverter.ToInt64(longB, 0);

     Console.Title += @"fileLength - (fileLength % "+partSize+")=" + (fileLength - (fileLength % partSize)).ToString();
     Console.Title += @"fileLength % "+partSize+"=" + (fileLength % partSize).ToString();

     Console.Title += "  fileLength specified=(long)" + fileLength.ToString();

     Thread.Sleep(200);

     byte[] fileData = new byte[fileLength];
     for(long i = 0; i < fileLength-partSize;)
     {

         for(long j = i; j < (i + 3 * partSize <= fileLength ? i + 3 * partSize : fileLength); j += partSize)
         {
             int byteCountToRead = (int)(fileLength - j > partSize ? partSize : fileLength % partSize);
             _ns.Read(fileData, (int)j, byteCountToRead);
         }
         byte[] hash = MD5.Create().ComputeHash(fileData, (int)i, (int)(fileLength - i >= 3000 ? 3000 : fileLength - i));//part size * n

         _ns.Write(hash, 0, hash.Length);

         while(!_ns.DataAvailable)
         {
         }

         byte[] hashResultBuf = new byte[4];
         _ns.Read(hashResultBuf, 0, 4);
         if(BitConverter.ToInt32(hashResultBuf, 0) == int.MaxValue / 3)
         {
             printl("good hash");
             //continue loop
             i += 3 * partSize;
         }
         else if(BitConverter.ToInt32(hashResultBuf, 0) == int.MaxValue / 5)
         {
             //wrong hash
             if(fileLength - i < 6000)
                 printl("\nwrong hash");
             else
                 printl("\nwrong hash with bytes:\n" + BitConverter.ToString(fileData, (int)i, 3000));
         }
     }
     receivingData = false;
     //play
 }

client part:

 void sendMediaFile(string path)
 {
 tcpClient.Client.DontFragment = true;
 maxPartSizeToSend = 1000;

 int partSize = maxPartSizeToSend;
 print("send file started");

 log("starting send media() with path=" + path);
 Stream _fs = new FileStream(path, FileMode.Open);//new Mp3FileReader(path);

 NetworkStream _ns = tcpClient.GetStream();


 _ns.Write(System.BitConverter.GetBytes((int)ioCommands.mediaFromBeyond), 0, 4);// it goes to receiver
 _ns.Write(System.BitConverter.GetBytes((int)partSize), 0, 4);// it goes throught receiver

 //server supose to wait for my commands and not send nothing, maybe a ping int.. so:
 while(_ns.DataAvailable)
 {
     _ns.ReadByte();
 }

 _ns.Write(System.BitConverter.GetBytes(_fs.Length), 0, 8);//it goes to func()
 byte[] _fsData = new byte[_fs.Length];

 _fs.Read(_fsData, 0, (int)_fs.Length);//so small, it's developed for songs

 for(long i = 0; i < _fs.Length;)
 {
     byte[] hash = MD5.Create().ComputeHash(_fsData, (int)i, (int)(_fs.Length - i >= 3000 ? 3000 : _fs.Length - i));//part size * n

     for(long j = i; j < (i+3*partSize<=_fs.Length?i+3*partSize:_fs.Length); j += partSize)
     {
         int byteCountToWrite = (int)(_fs.Length - j >= partSize ? partSize : _fs.Length % partSize);

         _ns.Write(_fsData, (int)j, byteCountToWrite);

     }

     byte[] hashBuf = new byte[hash.Length];
     _ns.Read(hashBuf, 0, hash.Length);

     if(hash.SequenceEqual(hashBuf))
     {
         _ns.Write(System.BitConverter.GetBytes(int.MaxValue / 3), 0, 4);//hash is good, next
         i += 3 * partSize;
     }
     else
     {
         print("resending");
         _ns.Write(System.BitConverter.GetBytes(int.MaxValue / 5), 0, 4);//resending
     }
 }
 }

one more thing - when i running client in unity editor and sending file, it works very well with 100% good hash sums.