C# Socket(server) Receives only half data

Question

I have a program like this:

class FTServerCode
    {
        IPEndPoint ipEnd;
        Socket sock;
        public FTServerCode()
        {
           ipEnd = new IPEndPoint(IPAddress.Any, 5656);
           sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);
           sock.Bind(ipEnd);
        }
        public static string receivedPath;
        public static string curMsg = "Stopped";
        public  void StartServer()
        {
            try
            {
                curMsg = "Starting...";
                sock.Listen(100);

                curMsg = "Running and waiting to receive file.";
                Socket clientSock = sock.Accept();

                byte[] clientData = new byte[1024 * 5000];

                int receivedBytesLen = clientSock.Receive(clientData);
                curMsg = "Receiving data...";

                int fileNameLen = BitConverter.ToInt32(clientData, 0);
                string fileName = Encoding.ASCII.GetString(clientData, 4, fileNameLen);

                BinaryWriter bWrite = new BinaryWriter(File.Open(receivedPath +"/"+ fileName, FileMode.Append)); ;
                bWrite.Write(clientData, 4 + fileNameLen, receivedBytesLen - 4 - fileNameLen);

                curMsg = "Saving file...";

                bWrite.Close();
                clientSock.Close();
                curMsg = "Reeived & Saved file; Server Stopped.";
            }
            catch (Exception ex)
            {
                curMsg = "File Receving error.";
            }
        }
    }

This program works but instead of receiving let's say total file size of 600KB it only receives 6KB of file. The program doesn't crash or anything but it only receives small fraction of file. What's wrong?

Answer 1

Problem : you are reading only once by calling the Receive() one time only.

Soution : You need to read the data until unless the Receive function gives you.use while loop to determine whether data is available or not.

Try This:

    int recv=0;
    byte[] data = new byte[1024];

    StringBuilder sb= new StringBuilder();
    while ((recv=clientSock.Receive(data)) > 0)
    {
        sb.Append(Encoding.ASCII.GetString(data, 0, recv));
    }

Complete Code:

class FTServerCode
{
   IPEndPoint ipEnd;
   Socket sock;
   public FTServerCode()
   {
      ipEnd = new IPEndPoint(IPAddress.Any, 5656);
      sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);
      sock.Bind(ipEnd);
   }
   public static string receivedPath;
   public static string curMsg = "Stopped";
   public  void StartServer()
   {
      try
      {
         curMsg = "Starting...";
         sock.Listen(100);

         curMsg = "Running and waiting to receive file.";
         Socket clientSock = sock.Accept();

         byte[] clientData = new byte[1024];
         StringBuilder sb= new StringBuilder();
         int receivedBytesLen = 0;
         int fileNameLen = 0;
         string fileName = "";
         BinaryWriter bWrite;
         while((receivedBytesLen =clientSock.Receive(clientData))>0)
         {
            curMsg = "Receiving data..."; 
            fileNameLen = BitConverter.ToInt32(clientData, 0);
            fileName = Encoding.ASCII.GetString(clientData, 4, fileNameLen);

            bWrite = new BinaryWriter(File.Open(receivedPath +"/"+ fileName, FileMode.Append)); ;
            bWrite.Write(clientData, 4 + fileNameLen, receivedBytesLen - 4 - fileNameLen);
         }
         curMsg = "Saving file...";

         bWrite.Close();
         clientSock.Close();
         curMsg = "Reeived & Saved file; Server Stopped.";
      }
      catch (Exception ex)
      {
         curMsg = "File Receving error.";
      }
   }
}

Answer 2

Most likely you need to put this in a loop until the read call returns 0

 int receivedBytesLen = clientSock.Receive(clientData);