Created initial connection logic for server and client

PDGServer_WPF/App.xaml.cs

@@ -20,6 +20,7 @@ namespace RBG_Server
     {
         public GameServer BoardGameServer {get;}
         public CommunicationHandler communicationHandler { get; private set;}
+
         protected static readonly SolidColorBrush RED_BRUSH = new(Color.FromRgb(255, 0, 0));
         protected static readonly SolidColorBrush BLUE_BRUSH = new(Color.FromRgb(0, 0, 255));
         protected static readonly SolidColorBrush GREEN_BRUSH = new(Color.FromRgb(0, 255, 0));

RBG_Server.Core/CommunicationHandler.cs

@@ -1,7 +1,10 @@
-using System;
+using NATUPNPLib;
+using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net;
+using System.Net.Sockets;
 using System.Text;
 using System.Threading.Tasks;
 
@@ -10,8 +13,12 @@ namespace RBG_Server
     /// <summary>
     /// Contains all communication data, from both the client's and server's perspective (should be able to switch between each mode as necessary)
     /// </summary>
+    /// 
     public class CommunicationHandler
     {
+        UPnPNAT upnpnat = new();
+        IStaticPortMapping portMapping;
+        
 
         /// <summary>
         /// Image data is stored in memory in a dictionary collection. Each byte[] represents an image file, compressed according to its file type;
@@ -20,5 +27,202 @@ namespace RBG_Server
         /// This limit can be changed at any time
         /// </summary>
         public ConcurrentDictionary<string, CachedByteArray> ImageCollection { get; } = new();
+        public List<string> ImageList {  get; } = new();
+        public string BoardName { get; set; }
+
+        public IPAddress IpAddress { get; set; }
+        public short Port { get; set; }
+
+        private TcpClient stateRetriever { get; set; }
+        private TcpClient dataRetriever { get; set; }
+
+
+        public int ColumnCount { get;private set; }
+        public int RowCount { get;private set; }
+        public int ColumnZoomStart { get;private set; }
+        public int RowZoomStart { get;private set; }
+        public int ColumnZoomSpan { get;private set; }
+        public int RowZoomSpan { get;private set; }
+        public int StartingColumn { get;private set; }
+        public int StartingRow { get;private set; }
+
+        public void InitialiseServer()
+        {
+            // Find the server's active (reliable) network adapter, by creating a remote connection and retrieving our IP from it:
+            using (Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp))
+            {
+                s.Bind(new IPEndPoint(IPAddress.Any, 0));
+                s.Connect("microsoft.com", 0);
+                // The IP is implicitly the one assigned to the interface the OS would use to connect to the remote address
+                IpAddress = (s.LocalEndPoint as IPEndPoint).Address;
+            }
+            // Create the upnp mapping
+            upnpnat.StaticPortMappingCollection.Add(Port, "TCP", Port, IpAddress.ToString(), true, "RBGServer");
+
+            TcpListener listener = new(IPAddress.Any, Port); // Allow local comms
+
+            listener.Start();
+            while (true)
+            {
+                TcpClient client = listener.AcceptTcpClient();
+                // Delegate to another thread
+                _ = Task.Run(() =>
+                {
+                    AcceptConnections(client);
+                });
+            }
+            // At this point, the ImageCollection will have already been initialised.
+            // The name of the board will also be set to <boardname>{0}.<extension>.
+            // Server logic, such as accepting players and maintaining communication goes in here
+        }
+
+        private void AcceptConnections(TcpClient client)
+        {
+            throw new NotImplementedException();
+        }
+
+        public void InitialiseClient(TcpClient client)
+        {
+            // At this point, no details about the game are loaded; we must load them from the server (to which we have already connected [no data should have been sent]).
+            NetworkStream stateStream = stateRetriever.GetStream();
+            Task stateLoader = new Task(async () =>
+            {
+                // Get game board details
+                byte[] buffer = new byte[] { 1, 0, 0, 0, 1 }; 
+                stateStream.Write(buffer, 0, buffer.Length);
+                // Response size
+                var stateResponse = await GetResponse(stateStream, 4);
+                // Response data
+                stateResponse = await GetResponse(stateStream, GetInt32(stateResponse)); // Get the full response data
+                // Board state data
+                ColumnCount = GetInt32(stateResponse[..4]);
+                RowCount = GetInt32(stateResponse[4..8]);
+                ColumnZoomStart = GetInt32(stateResponse[8..12]);
+                RowZoomStart = GetInt32(stateResponse[12..16]);
+                ColumnZoomSpan = GetInt32(stateResponse[16..20]);
+                RowZoomSpan = GetInt32(stateResponse[20..24]);
+                StartingColumn = GetInt32(stateResponse[24..28]);
+                StartingRow = GetInt32(stateResponse[28..32]);
+                // Basic board data loaded; fetch players
+                buffer = new byte[] { 1, 0, 0, 0, 2};
+                stateStream.Write(buffer, 0, buffer.Length);
+                stateResponse = await GetResponse(stateStream, 4);
+                stateResponse = await GetResponse(stateStream, GetInt32(stateResponse));
+                // state response contains a player list
+            });
+            
+
+
+            NetworkStream dataStream = dataRetriever.GetStream();
+            Task dataLoader = new Task(async () =>
+            {
+                byte[] buffer = new byte[] { 2, 0, 0, 0, 128, 0 }; // Get image collection names
+                dataStream.Write(buffer, 0, buffer.Length);
+                var dataResponse = await GetResponse(stateStream, 4);
+
+                dataResponse = await GetResponse(dataStream, GetInt32(dataResponse));
+                List<byte> data = new List<byte>();
+                for (int i = 0; i < dataResponse.Length; i++)
+                {
+                    if (dataResponse[i] != 0)
+                    {
+                        data.Add(dataResponse[i]);
+                    }
+                    else
+                    {
+                        ImageList.Add(Encoding.UTF8.GetString(data.ToArray()));
+                        data.Clear();
+                    }
+                }
+
+                // Load all low-resolution images
+                foreach (string item in ImageList)
+                {
+                    byte[] strBytes = Encoding.ASCII.GetBytes(item);
+                    buffer = new byte[strBytes.Length + 6];
+                    byte[] lenBytes = GetBytes(strBytes.Length + 6);
+                    lenBytes.CopyTo(buffer, 0);
+                    buffer[4] = 129; // Download image
+                    buffer[5] = 0; // mip_low
+                    strBytes.CopyTo(buffer, 6);
+                    dataStream.Write(buffer, 0, buffer.Length);
+                    // Read the length, then the data
+                    dataResponse = await GetResponse(dataStream);
+                    dataResponse = await GetResponse(dataStream, GetInt32(dataResponse));
+                    ImageCollection.TryAdd(item + "_mip_low", (CachedByteArray)dataResponse);
+                }
+                // At this point, the minimal amount of work required by the data thread has been done (load all thumbs)
+                // When an asset is needed from here, queue a load
+            });
+
+            dataLoader.Start();
+            stateLoader.Start();
+
+
+            byte[] buffer = new byte[] {0,0,0,1,1};
+            // Writing to the stream is to be considered near constant-time, but reading is non-constant.
+            // This application model must be synchronous, but we execute other commands before expecting our response to have arrived (it can complete at any time in that period)
+            stateStream.Write(buffer, 0, buffer.Length);
+            buffer[0] = 1;
+            buffer[3] = 0;
+            dataStream.Write(buffer, 0, buffer.Length);
+            // A details request is [<uint32, length>, <byte command>]
+            // The response is about the same format:
+            var stateResponse = GetResponse(stateStream, 4);
+            var dataResponse = GetResponse(dataStream, 4);
+            // First, load the board state (low mip-map, row definitions, column definitions, zoom position etc.)
+            // Retrieval command for the board
+            // Then load the player list, and use the low mip for their sprites
+            // Then check each loaded image and load the med, then large, then full sprite
+            // Then load the low of each unused image (for quick retrieval)
+        }
+
+        /// <summary>
+        /// Idea is that each response is prefaced by a 4 byte stream length specifier.
+        /// This requires a busy wait to achieve, if not all recieved at once.
+        /// We retrieve the 
+        /// </summary>
+        /// <param name="stream"></param>
+        /// <param name="targetLength"></param>
+        /// <returns></returns>
+        private async Task<byte[]> GetResponse(NetworkStream stream, int targetLength=4)
+        {
+            if (stream.CanRead)
+            {
+                byte[] buffer = new byte[targetLength];
+                StringBuilder myCompleteMessage = new StringBuilder();
+                int numberOfBytesRead = 0;
+
+                // Incoming message may be larger than the buffer size.
+                do
+                {
+                    numberOfBytesRead += await stream.ReadAsync(buffer, numberOfBytesRead, targetLength - numberOfBytesRead);
+                }
+                while (numberOfBytesRead < targetLength);
+                return buffer;
+            }
+            return Array.Empty<byte>();
+        }
+
+        static internal byte[] GetBytes(int i)
+        {
+            byte[] bytes = BitConverter.GetBytes(i);
+            if (BitConverter.IsLittleEndian)
+            {
+                // We need data in big-endian format; so reverse the array
+                Array.Reverse(bytes);
+            }
+            return bytes;
+        }
+
+        static internal int GetInt32(byte[] bytes)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                // We need data in little-endian format; so reverse the array
+                Array.Reverse(bytes);
+            }
+            return BitConverter.ToInt32(bytes, 0);
+        }
     }
 }

RBG_Server.Core/RBG_Server.csproj

@@ -4,6 +4,18 @@
     <TargetFramework>net5.0-windows10.0.19041.0</TargetFramework>
   </PropertyGroup>
 
+  <ItemGroup>
+    <COMReference Include="NATUPNPLib">
+      <WrapperTool>tlbimp</WrapperTool>
+      <VersionMinor>0</VersionMinor>
+      <VersionMajor>1</VersionMajor>
+      <Guid>1c565858-f302-471e-b409-f180aa4abec6</Guid>
+      <Lcid>0</Lcid>
+      <Isolated>false</Isolated>
+      <EmbedInteropTypes>true</EmbedInteropTypes>
+    </COMReference>
+  </ItemGroup>
+
   <ItemGroup>
     <FrameworkReference Include="Microsoft.WindowsDesktop.App.WPF" />
   </ItemGroup>