Add connection timeout using server keepalives

Vanilla client will consider that connection has been lost
when no server keepalive was received during the last 30 seconds.
This commit implements a similar mechanism in MCC. See #802

MinecraftClient/McTcpClient.cs

@@ -52,6 +52,8 @@ namespace MinecraftClient
         private string uuid;
         private string sessionid;
         private Inventory playerInventory;
+        private DateTime lastKeepAlive;
+        private object lastKeepAliveLock = new object();
 
         public int GetServerPort() { return port; }
         public string GetServerHost() { return host; }
@@ -64,6 +66,7 @@ namespace MinecraftClient
         TcpClient client;
         IMinecraftCom handler;
         Thread cmdprompt;
+        Thread timeoutdetector;
 
         /// <summary>
         /// Starts the main chat client
@@ -167,6 +170,10 @@ namespace MinecraftClient
                             cmdprompt = new Thread(new ThreadStart(CommandPrompt));
                             cmdprompt.Name = "MCC Command prompt";
                             cmdprompt.Start();
+
+                            timeoutdetector = new Thread(new ThreadStart(TimeoutDetector));
+                            timeoutdetector.Name = "MCC Connection timeout detector";
+                            timeoutdetector.Start();
                         }
                     }
                 }
@@ -253,6 +260,29 @@ namespace MinecraftClient
             catch (NullReferenceException) { }
         }
 
+        /// <summary>
+        /// Periodically checks for server keepalives and consider that connection has been lost if the last received keepalive is too old.
+        /// </summary>
+        private void TimeoutDetector()
+        {
+            lock (lastKeepAliveLock)
+            {
+                lastKeepAlive = DateTime.Now;
+            }
+            do
+            {
+                Thread.Sleep(TimeSpan.FromSeconds(15));
+                lock (lastKeepAliveLock)
+                {
+                    if (lastKeepAlive.AddSeconds(30) < DateTime.Now)
+                    {
+                        OnConnectionLost(ChatBot.DisconnectReason.ConnectionLost, "Connection Timeout");
+                    }
+                }
+            }
+            while (true);
+        }
+
         /// <summary>
         /// Perform an internal MCC command (not a server command, use SendText() instead for that!)
         /// </summary>
@@ -336,6 +366,9 @@ namespace MinecraftClient
             if (cmdprompt != null)
                 cmdprompt.Abort();
 
+            if (timeoutdetector != null)
+                timeoutdetector.Abort();
+
             Thread.Sleep(1000);
 
             if (client != null)
@@ -607,6 +640,10 @@ namespace MinecraftClient
         /// <param name="links">Links embedded in text</param>
         public void OnTextReceived(string text, bool isJson)
         {
+            lock (lastKeepAliveLock)
+            {
+                lastKeepAlive = DateTime.Now;
+            }
             List<string> links = new List<string>();
             string json = null;
             if (isJson)
@@ -637,11 +674,22 @@ namespace MinecraftClient
             }
         }
 
+        /// <summary>
+        /// Received a connection keep-alive from the server
+        /// </summary>
+        public void OnServerKeepAlive()
+        {
+            lock (lastKeepAliveLock)
+            {
+                lastKeepAlive = DateTime.Now;
+            }
+        }
+
         /// <summary>
         /// When an inventory is opened
         /// </summary>
         /// <param name="inventory">Location to reach</param>
-        public void onInventoryOpen(Inventory inventory)
+        public void OnInventoryOpen(Inventory inventory)
         {
             //TODO: Handle Inventory
             if (!inventories.Contains(inventory))
@@ -654,7 +702,7 @@ namespace MinecraftClient
         /// When an inventory is close
         /// </summary>
         /// <param name="inventoryID">Location to reach</param>
-        public void onInventoryClose(byte inventoryID)
+        public void OnInventoryClose(byte inventoryID)
         {
             for (int i = 0; i < inventories.Count; i++)
             {

MinecraftClient/Protocol/Handlers/Protocol16.cs

@@ -83,6 +83,7 @@ namespace MinecraftClient.Protocol.Handlers
             {
                 case 0x00: byte[] keepalive = new byte[5] { 0, 0, 0, 0, 0 };
                     Receive(keepalive, 1, 4, SocketFlags.None);
+                    handler.OnServerKeepAlive();
                     Send(keepalive); break;
                 case 0x01: readData(4); readNextString(); readData(5); break;
                 case 0x02: readData(1); readNextString(); readNextString(); readData(4); break;

MinecraftClient/Protocol/Handlers/Protocol18.cs

@@ -185,6 +185,7 @@ namespace MinecraftClient.Protocol.Handlers
                 {
                     case PacketIncomingType.KeepAlive:
                         SendPacket(PacketOutgoingType.KeepAlive, packetData);
+                        handler.OnServerKeepAlive();
                         break;
                     case PacketIncomingType.JoinGame:
                         handler.OnGameJoined();
@@ -481,7 +482,7 @@ namespace MinecraftClient.Protocol.Handlers
                             byte slots = dataTypes.ReadNextByte(packetData);
                             Inventory inventory = new Inventory(windowID, inventoryType, title, slots);
 
-                            handler.onInventoryOpen(inventory);
+                            handler.OnInventoryOpen(inventory);
                         }
                         break;
                     case PacketIncomingType.CloseWindow:
@@ -489,7 +490,7 @@ namespace MinecraftClient.Protocol.Handlers
                         {
                             byte windowID = dataTypes.ReadNextByte(packetData);
 
-                            handler.onInventoryClose(windowID);
+                            handler.OnInventoryClose(windowID);
                         }
                         break;
                     case PacketIncomingType.WindowItems:

MinecraftClient/Protocol/IMinecraftComHandler.cs

@@ -43,15 +43,20 @@ namespace MinecraftClient.Protocol
         /// <param name="isJson">TRUE if the text is JSON-Encoded</param>
         void OnTextReceived(string text, bool isJson);
 
+        /// <summary>
+        /// Called when receiving a connection keep-alive from the server
+        /// </summary>
+        void OnServerKeepAlive();
+
         /// <summary>
         /// Called when an inventory is opened
         /// </summary>
-        void onInventoryOpen(Inventory inventory);
+        void OnInventoryOpen(Inventory inventory);
 
         /// <summary>
         /// Called when an inventory is closed
         /// </summary>
-        void onInventoryClose(byte inventoryID);
+        void OnInventoryClose(byte inventoryID);
 
         /// <summary>
         /// Called when the player respawns, which happens on login, respawn and world change.