Sending detailed information using Sockets

[♪~ ᕕ(ᐛ)ᕗ]

C&P from my developers forum...


Hello fellow community,
Today I'll show you how to send a detailed amount of information using sockets in a simple and really efficient way.

We'll be using classes to carry those infos, a formatter to de/serialize the classes and two socket-based applications.

So first of all open up Visual Studio and go to File->New Project. Then create a 'Blank Solution', afterwards right click on the solution's name in the Solution Explorer, and choose 'Add->New Project' and create a Class Library named "test_lib".

Now before starting over there're some notes that you must take under consideration before continuing.

• BinaryFormatters can deserialize a class only if it's assembly is loaded.
• Maximum length of a socket is 30KB (so watch out for this, or you can split the packet if you want)

Now in this tutorial we will create a software which sends a Account information to the server, and the server then proceeds to store the information regarding the account.

[Serializable]
public class AccountInfo
{
      private string user_name;
      private int user_id;
      private bool active;

      public string Username{ get{ return user_name; } }
      public int ID{ get{ return user_id; } }
      public bool Active{ get{ return active; } }

      public AccountInfo(string un, int id, bool isactive)
      {
            user_name = un;
            user_id = id;
            active = isactive;
      }
}

This class pretty much explains itself but keep in mind to mark the class as "Serializable" in case that you want to serialize it, and also if you add a custom class inside it (ie a Stream class) then you cannot serialize it because each class member have to be serializable.

Next step is making the communication software. Let's start with the client:

using System;
using System.Net;
using System.Net.Sockets;
using System****;
using System.Runtime.Serialization.Formatters.Binary;
using test_lib; //Add our test_lib as a reference.

public class Program
{
      public static byte[] SerializeClass(object c)
      {
            MemoryStream memsr = new MemoryStream(); // A graph which will soon represent our object.
            BinaryFormatter bfmt = new BinaryFormatter(); // A binary formatter which will handle the serialization part.
            bfmt.Serialize(memsr, c); //Serialize the class.
            return memsr.ToArray();
      }
 
      public static void SendData(AccountInfo info)
      {
            byte[] data = SerializeClass(info);
            Socket s = new Socket( ... );  // '...' just to skip the parameters
            s.Connect(IPAddress.Parse("127.0.0.1"), 5588); // 127.0.0.1 is the localhost address and 5588 is our custom server's port.
            s.Send(data);
            s.Disconnect(false); //Disconnect the socket.
      }

      static void Main(string[] args)
      {
            Console.WriteLine("Please enter your account name:");
            string name = Console.ReadLine();

           int id = new Random().Next(0, 100);
           Console.Clear();
           Console.WriteLine("Sending your data...");
           SendData(new AccountInfo(name, id, true));
           Console.Write("DONE!");
           Console.Read();
      }
}

Now time to work with the server..

using System;
using System.Net;
using System.Net.Sockets;
using System****;
using System.Runtime.Serialization.Formatters.Binary;
using test_lib; //Add our test_lib as a reference.
using System.Threading;

class Program{

        static object Deserialize(byte[] o)
        {
               MemoryStream memsr = new MemoryStream(o); // A graph which represents our object.
            BinaryFormatter bfmt = new BinaryFormatter(); // A binary formatter which will handle the deserialization part.
            return bfmt.Deserialize(memsr); //Deerialize the class.
        }

        static void CreateRunThread()
        {
             Socket s = new Socket( ... );
             s.Bind((EndPoint)(new IPEndPoint(IPAddress.Any, 5588)));  //IPAddress.Any is recommended for this kind of operations.
             s.Listen(100); //Listens for incoming connections...
            while(true)
            { 
                  Socket client = s.Accept();
                  byte[] bytes = new byte[1024]; //1KB should be enough to handle the info's size.
                  client.Receive(bytes);
                  AccountInfo acc = (AccountInfo)Deserialize(bytes);
                  Console.WriteLine("Account received!\r\nName: " + acc.Username + "\r\nID: " + acc.ID.ToString() + "\r\nIs Active: " + acc.Active.ToString());
                  Console.Read();
            }
        }
        
        static void Main(string[] args)
        {
               new Thread(new ThreadStart(CreateRunThread)).Start(); //Starts the server stuffs.
               while(true) { Console.Title = "Server"; }
        }
}

Once ran the server then the client the server's output should be:

Name: Elio
ID: 52
Active: True

Hope it helps, Elio.