Added asynchronous ServerTester class, updated network code

Spark/Net/NetworkPacket.cs

@@ -21,6 +21,7 @@ public class NetworkPacket : INetworkPacket
         public virtual IReadOnlyList<byte> Data { get; protected set; }
         #endregion
 
+        #region Constructors
         public NetworkPacket(byte signature, short size, byte command, IEnumerable<byte> data = null)
         {
             this.Signature = signature;
@@ -38,6 +39,13 @@ public NetworkPacket(byte signature, short size, byte command, byte[] data, int
                 this.Data = new ArraySegment<byte>(data, offset, count).ToList();
         }
 
+        public NetworkPacket(params byte[] packet)
+            : this(packet, 0, packet.Length) { }
+
+        public NetworkPacket(byte[] packet, int offset, int count)
+            : this(packet[offset], IntegerExtender.MakeWord(packet[offset + 2], packet[offset + 1]), packet[offset + 3], packet, HeaderSize, count - HeaderSize) { }
+        #endregion
+
         public override string ToString()
         {
             // Returns a hex string of the packet ("AA 00 03 FF ...")

Spark/Net/NetworkPacketBuffer.cs

@@ -6,6 +6,7 @@
 
 namespace Spark.Net
 {
+    // This class buffers data bytes to create network packets that can be dequeued
     public sealed class NetworkPacketBuffer
     {
         static readonly int BufferSize = 4096;          // 4KB
@@ -55,7 +56,7 @@ void ProcessPacketBuffer()
             {
                 // Get the expected size of the packet
                 var size = IntegerExtender.MakeWord(buffer[2], buffer[1]);
-                var packetSize = size + 2;
+                var packetSize = size + 3;
 
                 // If the entire packet has not been buffered, stop processing until more data arrives
                 if (packetSize > buffer.Count)

Spark/Net/ServerTester.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
 using System.Net;
 using System.Net.Sockets;
 using System.Text;
@@ -12,18 +14,23 @@ namespace Spark.Net
     public class ServerTester : IServerTester
     {
         static readonly int BufferSize = 4096;  // 4KB
+        static readonly string ServerWelcomeMessage = "CONNECTED SERVER\n";
 
         bool isDisposed;
 
-        protected Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+        protected Socket socket;
         protected NetworkPacketBuffer packetBuffer = new NetworkPacketBuffer();
         protected byte[] receiveBuffer = new byte[BufferSize];
         protected byte[] sendBuffer = new byte[BufferSize];
 
-        public ServerTester() { }
+        public ServerTester()
+        {
+            socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+            socket.ReceiveTimeout = 1000;
+        }
 
         #region IServerTester Methods
-        public virtual Task ConnectToServerAsync(IPAddress ipAddress, int port)
+        public virtual async Task ConnectToServerAsync(IPAddress ipAddress, int port)
         {
             if (ipAddress == null)
                 throw new ArgumentNullException("ipAddress");
@@ -32,7 +39,28 @@ public virtual Task ConnectToServerAsync(IPAddress ipAddress, int port)
                 throw new ArgumentOutOfRangeException("Port must be greater than zero");
 
             CheckIfDisposed();
-            return socket.ConnectAsync(ipAddress, port);
+
+            // Connect to the server
+            await socket.ConnectAsync(ipAddress, port);
+
+            // Receive the initial welcome message packet
+            var welcomePacket = await ReceiveNextPacket();
+            Debug.WriteLine(string.Format("ReceivedPacket: {0}", welcomePacket));
+
+            // Get the welcome message ASCII bytes, skipping the first ESC control character (0x1B)
+            var welcomeString = Encoding.ASCII.GetString(welcomePacket.Data.Skip(1).ToArray());
+
+            // Check that the welcome message equals the expected string value
+            if (!string.Equals(welcomeString, ServerWelcomeMessage, StringComparison.Ordinal))
+                throw new Exception("A service was running at the specified location, but it doesn't appear to be a Darkages server.");
+
+            // Create a response packet
+            var responsePacket = new NetworkPacket(0xAA, 0x00, 0x0A, 0x62, 0x00, 0x34, 0x00, 0x0A, 0x88, 0x6E, 0x59, 0x59, 0x75);
+            var responsePacketData = responsePacket.ToArray();
+
+            // Send the response data to the server
+            await socket.SendAsync(responsePacketData, 0, responsePacketData.Length);
+            Debug.WriteLine(string.Format("SentPacket: {0}", responsePacket));
         }
 
         public virtual async Task<bool> CheckClientVersionCodeAsync(int versionCode)
@@ -42,8 +70,30 @@ public virtual async Task<bool> CheckClientVersionCodeAsync(int versionCode)
 
             CheckIfDisposed();
 
-            var packet = await ReceiveNextPacket();
+            // Create a client version packet
+            var version = (short)versionCode;
+            var versionPacket = new NetworkPacket(0xAA, 0x00, 0x06, 0x00, version.HiByte(), version.LoByte(), 0x4C, 0x4B, 0x00);
+            var versionPacketData = versionPacket.ToArray();
+
+            // Send the version packet to the server
+            await socket.SendAsync(versionPacketData, 0, versionPacketData.Length);
+            Debug.WriteLine(string.Format("SentPacket: {0}", versionPacket));
+
+            // Receive the response from the server
+            var responsePacket = await ReceiveNextPacket();
+            Debug.WriteLine(string.Format("ReceivedPacket: {0}", responsePacket));
+
+            // Get the status code from the response
+            var statusCode = responsePacket.Data[0];
+
+            if (statusCode > 0)
+            {
+                // Get the required version and raise an exception
+                var requiredVersion = IntegerExtender.MakeWord(responsePacket.Data[2], responsePacket.Data[1]);
+                throw new Exception(string.Format("The server requires client version {0} or higher.", requiredVersion));
+            }
 
+            // Version was accepted by the server
             return true;
         }
         #endregion

Spark/Spark.csproj

@@ -76,9 +76,7 @@
     <Compile Include="Input\AsyncDelegateCommand.cs" />
     <Compile Include="Input\DelegateCommand.cs" />
     <Compile Include="Input\InputMasking.cs" />
-    <Compile Include="Models\BasicVersionTester.cs" />
     <Compile Include="Models\ClientVersion.cs" />
-    <Compile Include="Models\IVersionTester.cs" />
     <Compile Include="Models\Serializers\ClientVersionSerializer.cs" />
     <Compile Include="Models\Serializers\UserSettingsSerializer.cs" />
     <Compile Include="Models\UserSettings.cs" />

Spark/ViewModels/MainViewModel.cs

@@ -15,6 +15,7 @@
 using Spark.Input;
 using Spark.Interop;
 using Spark.Models;
+using Spark.Net;
 using Spark.Runtime;
 using Spark.Security;
 
@@ -137,14 +138,12 @@ void OnTestConnection()
             Debug.WriteLine("OnTestConnection");
             Debug.WriteLine(string.Format("ServerHostname = {0},  ServerPort = {1}", this.UserSettings.ServerHostname, this.UserSettings.ServerPort));
 
-            int version;
             ClientVersion clientVersion;
 
-            #region Get Version Number
+            #region Get Client Version
             try
             {
                 clientVersion = DetectClientVersion(userSettings, clientVersions);
-                version = clientVersion.VersionCode;
             }
             catch (Exception ex)
             {
@@ -166,10 +165,11 @@ void OnTestConnection()
 
                 return;
             }
-            version = clientVersion.VersionCode;
             #endregion
 
-            TestConnectionToServer(userSettings.ServerHostname, userSettings.ServerPort, version);
+            Debug.WriteLine(string.Format("ClientVersion = {0} ({1})", clientVersion.Name, clientVersion.VersionCode));
+
+            TestConnectionToServer(userSettings.ServerHostname, userSettings.ServerPort, clientVersion.VersionCode);
         }
 
         void OnLaunchClient()
@@ -317,7 +317,7 @@ void LaunchClientWithSettings(UserSettings settings, IEnumerable<ClientVersion>
             #endregion
         }
 
-        void TestConnectionToServer(string serverHostname, int serverPort, int versionNumber)
+        async void TestConnectionToServer(string serverHostname, int serverPort, int versionCode)
         {
             IPAddress serverIPAddress = null;
 
@@ -355,32 +355,28 @@ void TestConnectionToServer(string serverHostname, int serverPort, int versionNu
 
             try
             {
-                using (IVersionTester versionTester = new BasicVersionTester())
+                using (var serverTester = new ServerTester())
                 {
-                    versionTester.ConnectToServer(serverIPAddress, serverPort);
-                    int reqVersionNumber;
-                    if (versionTester.TestVersionNumber(versionNumber, out reqVersionNumber))
+                    await serverTester.ConnectToServerAsync(serverIPAddress, serverPort);
+
+                    if (await serverTester.CheckClientVersionCodeAsync(versionCode))
                     {
                         this.DialogService.ShowOKDialog("Connection Successful",
                             "The server appears to be up and running.",
                             string.Format("Connected to {0}:{1} successfully.", serverIPAddress, serverPort));
                     }
                     else
                     {
-                        string extraInfo;
-                        // Known required version number?
-                        if (reqVersionNumber >= 0)
-                        {
-                            extraInfo = string.Format("Required Version: {0}. Detected Version: {1}.", reqVersionNumber, versionNumber);
-                        }
-                        else
-                        {
-                            extraInfo = string.Format("Detected Version: {0}. Please check what versions the server you are connecting to supports.", versionNumber);
-                        }
+                        //string extraInfo;
+                        //// Known required version number?
+                        //if (reqVersionNumber >= 0)
+                        //    extraInfo = string.Format("Required Version: {0}. Detected Version: {1}.", reqVersionNumber, versionNumber);
+                        //else
+                        //    extraInfo = string.Format("Detected Version: {0}. Please check what versions the server you are connecting to supports.", versionNumber);
 
                         this.DialogService.ShowOKDialog("Connection Failed",
                             "The server appears to be running, but requires a different version of the client.",
-                            extraInfo);
+                            null);
                     }
                 }
             }
@@ -397,7 +393,7 @@ void TestConnectionToServer(string serverHostname, int serverPort, int versionNu
 
                 // Retry the connection
                 if (result.HasValue && result.Value)
-                    TestConnectionToServer(serverHostname, serverPort, versionNumber);
+                    TestConnectionToServer(serverHostname, serverPort, versionCode);
             }
         }