File Transfer using C# .Net Socket Programming

File transfer using C# socket is Client-Server combined process and quite complex too. This process we can divide in three phases.

1. Preparation stage for Server and Client.
2. Establish communication channel to send-receive data between Client and Server.
3. Break the communication channel and release all resources.

To complete data transfer from client to server need to follow below steps as describe in table. Later discussing about each steps but before that go trough the logic which I am going to follow. 

File Transfer from Client to Server

Server

Client

1. Server creates an IP End Point and a socket object then bind socket object with IP end point and sends it to listen mode for incoming client request. 5. Server receive client request and accept it. Once connection established, server create another socket object which will handle this client all requests until connection ends. Client will be informed internally by TCP about connect success. 6. Start preparations to store incoming byte data from client. 8. Server receives file byte data along with file name and stores it in byte array. 9. Server retrieve file name from byte data. 10. Server opens a binary stream writer with file name to store byte data in it.    11. Once file save complete server closes binary stream writer and server socket objects. 14 Server program ends here.

2. Client creates an IP End Point and a socket object.  3. Prepare byte data from file which will be sent to server. 4. Try to connect to server using client socket by help of IP end point. 7. Client starts sending byte data over connected socket. 12. Once data transfer complete and server closes socket connection, client also close client socket object. 13. Client program work ends here.

 

Phase 1, Preparation: In that phase server and client both prepared to send some data.

At Server: Server makes an object of IPEndPoint class with some Port number with some IP address. Then creates a socket object with Internetwork family with protocol type IP(or IDP or else) to transfer Stream type data. At last bind this socket objects with that IPEndPoint object and place socket in listen mode to accept client request.

At Client: Client makes another IPEndPoint object with Server IP address and same port number. Then creates a socket object as same as Server socket object in same way. After completing these client reads a file and stores bytes data in a byte array object.

Phase 2, Establish communication and transfer data: Now client socket tries to connect to server socket which was in listen mode. When server socket get requests from client then it accept request and established connection between server and client by producing a new socket object. Next data transmission operation continues by that new socket object.

When new client socket request accepted by server and connection established then client send byte data by “socket-object. Send()” method to server and at server end these data received by “socket-object. Receive()” method. When data successfully received at server end, server saves these bytes in a file using byte data stream.

For large file, “these data read at client -send to server-receive at server end - save received data at server end” these steps are perform repeatedly until client reach at EOF (End Of File). But in this program only small file covered for this no need of looping, for this type of example read my “Send 2GB file using TCP socket programming” article.

Phase 3, Break communication channel and release resources: When last slice of byte data saved at server, client and server close the socket object and release all resource like file stream, socket object etc.

By that way a file transferred from client to server. But there has no way to call a client from server and send file. My example describe how to send file from client to server but can you imagine how opposite done? Yes if you able learn client to server data transfer properly then it is very easy. Try your self first, if failed then try it again and continue at least three times, then you will able to do it. But….but again failed then ask me I will help you about it :-).

For code url is:

Client Code:

[C#]

using System;

using System.Collections.Generic;

using System.Text;

using System.Net;

using System.Net.Sockets;

using System.IO;

namespace Client_Socket

{

//FILE TRANSFER USING C#.NET SOCKET PROGRAMMING - CLIENT

class Program

{

static void Main(string[] args)

{

try

{

Console.WriteLine("That program can transfer small file. I've test up to 850kb file");

IPAddress[] ipAddress = Dns.GetHostAddresses("localhost");

IPEndPoint ipEnd = new IPEndPoint(ipAddress[0], 5656);

Socket clientSock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);

string fileName = "Your File Name";

string filePath = "Your File Path";

byte[] fileNameByte = Encoding.ASCII.GetBytes(fileName);

byte[] fileData = File.ReadAllBytes(filePath + fileName);

byte[] clientData = new byte[4 + fileNameByte.Length + fileData.Length];

byte[] fileNameLen = BitConverter.GetBytes(fileNameByte.Length);

fileNameLen.CopyTo(clientData, 0);

fileNameByte.CopyTo(clientData, 4);

fileData.CopyTo(clientData, 4 + fileNameByte.Length);

clientSock.Connect(ipEnd);

clientSock.Send(clientData);

Console.WriteLine("File:{0} has been sent.", fileName);

clientSock.Close();

Console.ReadLine();

}

catch (Exception ex)

{

Console.WriteLine("File Sending fail." + ex.Message);

}

}

}

}

[Visual Basic]

Imports System
Imports System.Collections.Generic
Imports System.Text
Imports System.Net
Imports System.Net.Sockets
Imports System.IO
Namespace Client_Socket
'FILE TRANSFER USING C#.NET SOCKET PROGRAMMING- CLIENT
Class Program
Private Shared Sub Main(ByVal args As String())
Try
Console.WriteLine("That program can transfer small file. I've test up to 850kb file")
Dim ipAddress As IPAddress() = Dns.GetHostAddresses("localhost")
Dim ipEnd As New IPEndPoint(ipAddress(0), 5656)
Dim clientSock As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP)
Dim fileName As String = "Your File Name"
Dim filePath As String = "Your File Path"
Dim fileNameByte As Byte() = Encoding.ASCII.GetBytes(fileName)
Dim fileData As Byte() = File.ReadAllBytes(filePath + fileName)
Dim clientData As Byte() = New Byte(4 + fileNameByte.Length + (fileData.Length - 1)) {}
Dim fileNameLen As Byte() = BitConverter.GetBytes(fileNameByte.Length)
fileNameLen.CopyTo(clientData, 0)
fileNameByte.CopyTo(clientData, 4)
fileData.CopyTo(clientData, 4 + fileNameByte.Length)
clientSock.Connect(ipEnd)
clientSock.Send(clientData)
Console.WriteLine("File:{0} has been sent.", fileName)
clientSock.Close()
Console.ReadLine()
Catch ex As Exception
Console.WriteLine("File Sending fail." & ex.Message)
End Try
End Sub
End Class
End Namespace

Continued code...

Server Code:

[C#]

using System;

using System.Collections.Generic;

using System.Text;

using System.Net;

using System.Net.Sockets;

using System.IO;

namespace beginSocketServer

{

//FILE TRANSFER USING C#.NET SOCKET PROGRAMMING - SERVER

class Program

{

static void Main(string[] args)

{

try

{

Console.WriteLine("That program can transfer small file. I've test up to 850kb file");

IPEndPoint ipEnd = new IPEndPoint(IPAddress.Any, 5656);

Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);

sock.Bind(ipEnd);

sock.Listen(100);

Socket clientSock = sock.Accept();

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

string receivedPath = "e:/";

int receivedBytesLen = clientSock.Receive(clientData);

int fileNameLen = BitConverter.ToInt32(clientData, 0);

string fileName = Encoding.ASCII.GetString(clientData, 4, fileNameLen);

Console.WriteLine("Client:{0} connected & File {1} started received.", clientSock.RemoteEndPoint, fileName);

BinaryWriter bWrite = new BinaryWriter(File.Open(receivedPath + fileName, FileMode.Append)); ;

bWrite.Write(clientData, 4 + fileNameLen, receivedBytesLen - 4 - fileNameLen);

Console.WriteLine("File: {0} received & saved at path: {1}", fileName, receivedPath);

bWrite.Close();

clientSock.Close();

Console.ReadLine();

}

catch (Exception ex)

{

Console.WriteLine("File Receiving fail." + ex.Message);

}

}

}

}

[Visual Basic]

Imports System

Imports System.Collections.Generic

Imports System.Text

Imports System.Net

Imports System.Net.Sockets

Imports System.IO

Namespace beginSocketServer

'FILE TRANSFER USING C#.NET SOCKET PROGRAMMING- SERVER

Class Program

Private Shared Sub Main(ByVal args As String())

Try

Console.WriteLine("That program can transfer small file. I've test up to 850kb file")

Dim ipEnd As New IPEndPoint(IPAddress.Any, 5656)

Dim sock As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP)

sock.Bind(ipEnd)

sock.Listen(100)

Dim clientSock As Socket = sock.Accept()

Dim clientData As Byte() = New Byte(1024 5000 - 1) {}

Dim receivedPath As String = "e:/"

Dim receivedBytesLen As Integer = clientSock.Receive(clientData)

Dim fileNameLen As Integer = BitConverter.ToInt32(clientData, 0)

Dim fileName As String = Encoding.ASCII.GetString(clientData, 4, fileNameLen)

Console.WriteLine("Client:{0} connected & File {1} started received.", clientSock.RemoteEndPoint, fileName)

Dim bWrite As New BinaryWriter(File.Open(receivedPath + fileName, FileMode.Append))

bWrite.Write(clientData, 4 + fileNameLen, receivedBytesLen - 4 - fileNameLen)

Console.WriteLine("File: {0} received & saved at path: {1}", fileName, receivedPath)

bWrite.Close()

clientSock.Close()

Console.ReadLine()

Catch ex As Exception

Console.WriteLine("File Receiving fail." & ex.Message)

End Try

End Sub

End Class

End Namespace