Create single server for multi-platform game (pc, mobile, etc)

Hello, @skoff.

I'm working on a simple MMO game with Unity and Go (GoLang) as server to test Unity networking with C#.

You can look at my starting project here. I have a simple code to notify server on key press.

I recommend to use native sockets, because are faster and server side with C++, Java or Go can handle a lot of users.

I'm using a simple structure for sockets. Look at my code: https://github.com/izanbf1803/Unity-GoLang--MMO-Game

 public class Message {
     public int Len;
     public SOCKET_TAG Tag;
     public string Data;
 }

First 4 bytes ( sizeof int ) are the length of the data. Next 4 bytes are the socket tag. ( enum ). Next bytes (size defined in the fist 4 bytes) are all the data.

I can make a switch with the tag: example:

 switch (msg.tag) {
     case TAG.SET_ID:
        client.id = msg.data;
        break:
     case TAG.POSITION_CHANGED:
         client.position = positionDecode(msg.data)
         break;
 }

The server side and the client are threaded. A simple thread for recive sockets and push to a queue, and the main thead reads the queue and uses the data:

 private void Input() {    // Threaded
         while (true) {
             try {
                 Message _in = Recv();
                 lock (queueLock) {
                     queue.Enqueue(_in);
                 }
             } catch (SocketException e) {
                 break;
             }
         }
     }

 void ClientUpdate() {
         while (client.queue.Count > 0) {
             Message msg;
             lock (client.queueLock)
                 msg = client.queue.Dequeue();
 
             switch (msg.Tag) {
                 case SOCKET_TAG.SET_ID:
                     client.ID = int.Parse(msg.Data);
                     break;
             }
         }
     }

How i create the struct? here you have:

 public void Send(SOCKET_TAG tag, string msg) {
         byte[] data = ascii.GetBytes(msg);
         int len = data.Length;
 
         byte[] packet = new byte[sizeof(int) * 2 + len];
 
         packet[0] = (byte)(len);
         packet[1] = (byte)(len >> 8);     // this encodes an integer to 4 bytes:
         packet[2] = (byte)(len >> 16);   // 3060 -> [244, 11, 0, 0]
         packet[3] = (byte)(len >> 24);
 
         packet[4] = (byte)((int)tag);
         packet[5] = (byte)((int)tag >> 8);      // this encodes an integer to 4 bytes:
         packet[6] = (byte)((int)tag >> 16);    // 3060 -> [244, 11, 0, 0]
         packet[7] = (byte)((int)tag >> 24);
 
         System.Buffer.BlockCopy(data, 0, packet, sizeof(int)*2, len);
         
         lock (sendLock)
             conn.Send(packet, 0, packet.Length, SocketFlags.None);
     }

Look at my repo for more info.