Packet Serialization

패킷 직렬화

Packet Serialization ?

간단히 말해, 서버와 클라이언트간의 소통을 패킷으로 할건데,
보내기 전에 압축해서 보낸다고 생각하면 된다.

메모리상의 인스턴스로 존재하는 것을 압축해서 버퍼안에 밀어 넣는 것이라 생각하자.

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Client 프로젝트에서 Server 와 통신하기 위한 ServerSession 클래스

namespace DummyClient
{
    class Packet //패킷 헤더
    {
        public ushort size;
        public ushort packetId;
    }

    class PlayerInfoReq : Packet
    {
        public long playerId;
    }

    class PlayerInfoOk : Packet
    {
        public int hp;
        public int attack;
    }

    public enum PacketID
    {
        PlayerInfoReq = 1,
        PlayerInfoOk = 2,
    }

    class ServerSession : Session
    {
        public override void OnConnected(EndPoint endPoint)
        {
            Console.WriteLine($"OnConnected !{endPoint}");

            PlayerInfoReq packet = new PlayerInfoReq() {packetId = (ushort)PacketID.PlayerInfoReq, playerId = 1001};

            //보낸다
            //for (int i = 0; i < 5; i++)
            {
                ArraySegment<byte> s = SendBufferHelper.Open(4096);

                ushort count = 0;
                bool success = true;
                // &= (and연산) 중간에 한번이라도 계산에 실패하면 false를 반환
                // 그럼 TryWriteBytes가 실패하는 경우는 ? 
                // 애당초 2바이트짜리 크기인데 넣어주는 
                //packet.size의 부분이 8바이트 짜리면 공간이 모자라서 실패
                //success &= BitConverter.TryWriteBytes(new Span<byte>(s.Array, s.Offset, s.Count), packet.size);
                count += 2;
                success &= BitConverter.TryWriteBytes(new Span<byte>(s.Array, s.Offset + count, s.Count - count), packet.packetId);
                count += 2;
                success &= BitConverter.TryWriteBytes(new Span<byte>(s.Array, s.Offset + count, s.Count - count), packet.playerId);
                
                count += 8;
                //우리가 pakcet.size는 다 추가한 후에서야 알 수있으니 마지막에 추가
                success &= BitConverter.TryWriteBytes(new Span<byte>(s.Array, s.Offset, s.Count), count);

                //byte[] size = BitConverter.GetBytes(packet.size); // ushort 2바이트
                //byte[] packetId = BitConverter.GetBytes(packet.packetId); // ushort 2바이트
                //byte[] playerId = BitConverter.GetBytes(packet.playerId); // long 8바이트

                ArraySegment<byte> sendBuff = SendBufferHelper.Close(count);
                if(success)
                    Send(sendBuff);
            }
        }

        public override void OnDisconnected(EndPoint endPoint)
        {
            Console.WriteLine($"OnDisconnected !{endPoint}");
        }

        public override int OnRecv(ArraySegment<byte> buffer)
        {
            string recvData = Encoding.UTF8.GetString(buffer.Array, buffer.Offset, buffer.Count);
            Console.WriteLine($"[From Server] {recvData}");

            return buffer.Count;
        }

        public override void OnSend(int numOfBytes)
        {
            Console.WriteLine($"Transferred bytes : {numOfBytes}");
        }
    }
}

---

Server에서 Client값을 받는 ClientSession

namespace Server
{
    class Packet //패킷 헤더
    {
        public ushort size;
        public ushort packetId;
    }

    class PlayerInfoReq : Packet
    {
        public long plyareId;
    }

    class PlayerInfoOk : Packet
    {
        public int hp;
        public int attack;
    }

    public enum PacketID
    {
        PlayerInfoReq = 1,
        PlayerInfoOk = 2,
    }
    class ClientSession : PacketSession
    {
        public override void OnConnected(EndPoint endPoint)
        {
            Console.WriteLine($"OnConnected !{endPoint}");
			//OnRecvPacket이 잘오는지 확인하기 위해 잠시 주석처리
            //Packet packet = new Packet() { size = 100, packetId = 10 };

            //ArraySegment<byte> openSegment = SendBufferHelper.Open(4096);
            //byte[] buffer = BitConverter.GetBytes(packet.size);
            //byte[] buffer2 = BitConverter.GetBytes(packet.packetId);
            //Array.Copy(buffer, 0, openSegment.Array, openSegment.Offset, buffer.Length);
            //Array.Copy(buffer2, 0, openSegment.Array, openSegment.Offset + buffer.Length, buffer2.Length);
            //ArraySegment<byte> sendBuff = SendBufferHelper.Close(buffer.Length + buffer2.Length);

            //Send(sendBuff);
            Thread.Sleep(5000);
            Disconnect();
        }
        public override void OnRecvPacket(ArraySegment<byte> buffer)
        {
            ushort count = 0;

            ushort size = BitConverter.ToUInt16(buffer.Array, buffer.Offset);
            count += 2;
            ushort id = BitConverter.ToUInt16(buffer.Array, buffer.Offset + count);
            count += 2;
            

            switch((PacketID)id)
            {
                case PacketID.PlayerInfoReq:
                    {
                        long playerId = BitConverter.ToInt64(buffer.Array, buffer.Offset + count);
                        count += 8;
                        Console.WriteLine($"PlayerInfoReq : {playerId} ");
                    }
                    break;
                
            }
        }

        public override void OnDisconnected(EndPoint endPoint)
        {
            Console.WriteLine($"OnDisconnected !{endPoint}");
        }



        public override void OnSend(int numOfBytes)
        {
            Console.WriteLine($"Transferred bytes : {numOfBytes}");
        }
    }
}