addresses connection issues

TLSharp.Core/Network/TcpTransport.cs

@@ -12,23 +12,38 @@ namespace TLSharp.Core.Network
 
     public class TcpTransport : IDisposable
     {
-        private readonly TcpClient tcpClient;
-        private readonly NetworkStream stream;
+        private TcpClient tcpClient;
+        private NetworkStream stream;
         private int sendCounter = 0;
+        TcpClientConnectionHandler handler;
+        string address;
+        int port;
+        IPAddress ipAddress; 
 
         public TcpTransport(string address, int port, TcpClientConnectionHandler handler = null)
+        {
+            this.handler = handler;
+            this.address = address;
+            this.port = port;
+            ipAddress = IPAddress.Parse(address);
+        }
+
+        public async Task Connect()
         {
             if (handler == null)
             {
-                var ipAddress = IPAddress.Parse(address);
-                var endpoint = new IPEndPoint(ipAddress, port);
-
+                if (tcpClient != null)
+                {
+                    tcpClient.Close();
+                }
                 tcpClient = new TcpClient(ipAddress.AddressFamily);
+                sendCounter = 0;
 
-                try {
-                    tcpClient.Connect (endpoint);
+                try
+                {
+                    await tcpClient.ConnectAsync(ipAddress, port);
                 } catch (Exception ex) {
-                    throw new Exception ($"Problem when trying to connect to {endpoint}; either there's no internet connection or the IP address version is not compatible (if the latter, consider using DataCenterIPVersion enum)",
+                    throw new Exception ($"Problem when trying to connect to {ipAddress}:{port}; either there's no internet connection or the IP address version is not compatible (if the latter, consider using DataCenterIPVersion enum)",
                                          ex);
                 }
             }
@@ -102,7 +117,7 @@ public bool IsConnected
         {
             get
             {
-                return this.tcpClient.Connected;
+                return this.tcpClient != null && this.tcpClient.Connected;
             }
         }
 

TLSharp.Core/TelegramClient.cs

@@ -32,6 +32,8 @@ public class TelegramClient : IDisposable
         private List<TLDcOption> dcOptions;
         private TcpClientConnectionHandler handler;
         private DataCenterIPVersion dcIpVersion;
+        private ISessionStore store;
+        string sessionUserId;
 
         public Session Session
         {
@@ -56,22 +58,32 @@ public TelegramClient(int apiId, string apiHash,
             if (string.IsNullOrEmpty(apiHash))
                 throw new MissingApiConfigurationException("API_HASH");
 
-            if (store == null)
-                store = new FileSessionStore();
+            this.store = store ?? new FileSessionStore();
+            this.sessionUserId = sessionUserId;
 
             this.apiHash = apiHash;
             this.apiId = apiId;
             this.handler = handler;
             this.dcIpVersion = dcIpVersion;
 
-            session = Session.TryLoadOrCreateNew(store, sessionUserId);
+            session = Session.TryLoadOrCreateNew(this.store, sessionUserId);
             transport = new TcpTransport (session.DataCenter.Address, session.DataCenter.Port, this.handler);
         }
 
         public async Task ConnectAsync(bool reconnect = false, CancellationToken token = default(CancellationToken))
         {
             token.ThrowIfCancellationRequested();
 
+            if (!transport.IsConnected)
+            {
+                // we must recreate the session because it might track dirty information 
+                // of a connection that maybe was disconnected, reusing that session will cause errors
+                session = Session.TryLoadOrCreateNew(store, sessionUserId);
+                await transport.Connect();
+            }
+            if (!transport.IsConnected)
+                throw new Exception("Connection to Telegram failed");
+
             if (session.AuthKey == null || reconnect)
             {
                 var result = await Authenticator.DoAuthentication(transport, token).ConfigureAwait(false);