Removed HandleUpdatesBeforeConfirmation flag, allow messages to trigger listeners even if not confirmed and mark as confirmed then. Updated websocket reconnection delay handling

CryptoExchange.Net/Clients/SocketApiClient.cs

@@ -52,11 +52,6 @@ namespace CryptoExchange.Net.Clients
         /// </summary>
         protected internal bool UnhandledMessageExpected { get; set; }
 
-        /// <summary>
-        /// If true a subscription will accept message before the confirmation of a subscription has been received
-        /// </summary>
-        protected bool HandleMessageBeforeConfirmation { get; set; }
-
         /// <summary>
         /// The rate limiters 
         /// </summary>
@@ -203,7 +198,6 @@ namespace CryptoExchange.Net.Clients
                         return socketResult.As<UpdateSubscription>(null);
 
                     socketConnection = socketResult.Data;
-                    subscription.HandleUpdatesBeforeConfirmation = subscription.HandleUpdatesBeforeConfirmation || HandleMessageBeforeConfirmation;
 
                     // Add a subscription on the socket connection
                     var success = socketConnection.AddSubscription(subscription);
@@ -250,12 +244,19 @@ namespace CryptoExchange.Net.Clients
                 if (!subResult)
                 {
                     waitEvent?.Set();
+                    var isTimeout = subResult.Error is CancellationRequestedError;
+                    if (isTimeout && subscription.Confirmed)
+                    {
+                        // No response received, but the subscription did receive updates. We'll assume success
+                    }
+                    else
+                    {
                         _logger.FailedToSubscribe(socketConnection.SocketId, subResult.Error?.ToString());
                         // If this was a timeout we still need to send an unsubscribe to prevent messages coming in later
-                    var unsubscribe = subResult.Error is CancellationRequestedError;
+                        await socketConnection.CloseAsync(subscription, isTimeout).ConfigureAwait(false);
-                    await socketConnection.CloseAsync(subscription, unsubscribe).ConfigureAwait(false);
                         return new CallResult<UpdateSubscription>(subResult.Error!);
                     }
+                }
 
                 subscription.HandleSubQueryResponse(subQuery.Response!);
             }
@@ -517,7 +518,7 @@ namespace CryptoExchange.Net.Clients
         /// <param name="address">The address to connect to</param>
         /// <returns></returns>
         protected virtual WebSocketParameters GetWebSocketParameters(string address)
-            => new(new Uri(address), ClientOptions.AutoReconnect)
+            => new(new Uri(address), ClientOptions.ReconnectPolicy)
             {
                 KeepAliveInterval = KeepAliveInterval,
                 ReconnectInterval = ClientOptions.ReconnectInterval,

CryptoExchange.Net/Interfaces/IMessageProcessor.cs

@@ -16,10 +16,6 @@ namespace CryptoExchange.Net.Interfaces
         /// </summary>
         public int Id { get; }
         /// <summary>
-        /// Whether this listener can handle data
-        /// </summary>
-        public bool CanHandleData { get; }
-        /// <summary>
         /// The identifiers for this processor
         /// </summary>
         public HashSet<string> ListenerIdentifiers { get; }

CryptoExchange.Net/Objects/Enums.cs

@@ -169,4 +169,23 @@
         /// </summary>
         Snapshot
     }
+
+    /// <summary>
+    /// Reconnect policy
+    /// </summary>
+    public enum ReconnectPolicy
+    {
+        /// <summary>
+        /// Reconnect is disabled
+        /// </summary>
+        Disabled,
+        /// <summary>
+        /// Fixed delay of `ReconnectInterval` between retries
+        /// </summary>
+        FixedDelay,
+        /// <summary>
+        /// Backof policy of 2^`reconnectAttempt`, where `reconnectAttempt` has a max value of 5
+        /// </summary>
+        ExponentialBackoff
+    }
 }

CryptoExchange.Net/Objects/Options/SocketExchangeOptions.cs

@@ -1,4 +1,5 @@
 using CryptoExchange.Net.Authentication;
+using CryptoExchange.Net.Objects.Sockets;
 using System;
 
 namespace CryptoExchange.Net.Objects.Options
@@ -9,15 +10,15 @@ namespace CryptoExchange.Net.Objects.Options
     public class SocketExchangeOptions : ExchangeOptions
     {
         /// <summary>
-        /// Whether or not the socket should automatically reconnect when losing connection
+        /// The fixed time to wait between reconnect attempts, only used when `ReconnectPolicy` is set to `ReconnectPolicy.ExponentialBackoff`
-        /// </summary>
-        public bool AutoReconnect { get; set; } = true;
-
-        /// <summary>
-        /// Time to wait between reconnect attempts
         /// </summary>
         public TimeSpan ReconnectInterval { get; set; } = TimeSpan.FromSeconds(5);
 
+        /// <summary>
+        /// Reconnect policy
+        /// </summary>
+        public ReconnectPolicy ReconnectPolicy { get; set; } = ReconnectPolicy.FixedDelay;
+
         /// <summary>
         /// Max number of concurrent resubscription tasks per socket after reconnecting a socket
         /// </summary>
@@ -57,7 +58,7 @@ namespace CryptoExchange.Net.Objects.Options
             {
                 ApiCredentials = ApiCredentials?.Copy(),
                 OutputOriginalData = OutputOriginalData,
-                AutoReconnect = AutoReconnect,
+                ReconnectPolicy = ReconnectPolicy,
                 DelayAfterConnect = DelayAfterConnect,
                 MaxConcurrentResubscriptionsPerSocket = MaxConcurrentResubscriptionsPerSocket,
                 ReconnectInterval = ReconnectInterval,

CryptoExchange.Net/Objects/Sockets/WebSocketParameters.cs

@@ -26,20 +26,20 @@ namespace CryptoExchange.Net.Objects.Sockets
         public IDictionary<string, string> Cookies { get; set; } = new Dictionary<string, string>();
 
         /// <summary>
-        /// The time to wait between reconnect attempts
+        /// The fixed time to wait between reconnect attempts, only used when `ReconnectPolicy` is set to `ReconnectPolicy.ExponentialBackoff`
         /// </summary>
         public TimeSpan ReconnectInterval { get; set; } = TimeSpan.FromSeconds(5);
 
+        /// <summary>
+        /// Reconnect policy
+        /// </summary>
+        public ReconnectPolicy ReconnectPolicy { get; set; } = ReconnectPolicy.FixedDelay;
+
         /// <summary>
         /// Proxy for the connection
         /// </summary>
         public ApiProxy? Proxy { get; set; }
 
-        /// <summary>
-        /// Whether the socket should automatically reconnect when connection is lost
-        /// </summary>
-        public bool AutoReconnect { get; set; }
-
         /// <summary>
         /// The maximum time of no data received before considering the connection lost and closting/reconnecting the socket
         /// </summary>
@@ -68,11 +68,11 @@ namespace CryptoExchange.Net.Objects.Sockets
         /// ctor
         /// </summary>
         /// <param name="uri">Uri</param>
-        /// <param name="autoReconnect">Auto reconnect</param>
+        /// <param name="policy">Reconnect policy</param>
-        public WebSocketParameters(Uri uri, bool autoReconnect)
+        public WebSocketParameters(Uri uri, ReconnectPolicy policy)
         {
             Uri = uri;
-            AutoReconnect = autoReconnect;
+            ReconnectPolicy = policy;
         }
     }
 }

CryptoExchange.Net/Sockets/CryptoExchangeWebSocketClient.cs

@@ -47,6 +47,7 @@ namespace CryptoExchange.Net.Sockets
         private ProcessState _processState;
         private DateTime _lastReconnectTime;
         private string _baseAddress;
+        private int _reconnectAttempt;
 
         private const int _receiveBufferSize = 1048576;
         private const int _sendBufferSize = 4096;
@@ -246,7 +247,7 @@ namespace CryptoExchange.Net.Sockets
                 await _closeTask.ConfigureAwait(false);
                 _closeTask = null;
 
-                if (!Parameters.AutoReconnect)
+                if (Parameters.ReconnectPolicy == ReconnectPolicy.Disabled)
                 {
                     _processState = ProcessState.Idle;
                     await (OnClose?.Invoke() ?? Task.CompletedTask).ConfigureAwait(false);
@@ -259,9 +260,9 @@ namespace CryptoExchange.Net.Sockets
                     await (OnReconnecting?.Invoke() ?? Task.CompletedTask).ConfigureAwait(false);                    
                 }
 
-                var sinceLastReconnect = DateTime.UtcNow - _lastReconnectTime;
+                // Delay here to prevent very repid looping when a connection to the server is accepted and immediately disconnected
-                if (sinceLastReconnect < Parameters.ReconnectInterval)
+                var initialDelay = GetReconnectDelay();
-                    await Task.Delay(Parameters.ReconnectInterval - sinceLastReconnect).ConfigureAwait(false);
+                await Task.Delay(initialDelay).ConfigureAwait(false);
 
                 while (!_stopRequested)
                 {
@@ -282,13 +283,17 @@ namespace CryptoExchange.Net.Sockets
                     _ctsSource = new CancellationTokenSource();
                     while (_sendBuffer.TryDequeue(out _)) { } // Clear send buffer
 
+                    _reconnectAttempt++;
                     var connected = await ConnectInternalAsync().ConfigureAwait(false);
                     if (!connected)
                     {
-                        await Task.Delay(Parameters.ReconnectInterval).ConfigureAwait(false);
+                        // Delay between reconnect attempts
+                        var delay = GetReconnectDelay();
+                        await Task.Delay(delay).ConfigureAwait(false);
                         continue;
                     }
 
+                    _reconnectAttempt = 0;
                     _lastReconnectTime = DateTime.UtcNow;
                     await (OnReconnected?.Invoke() ?? Task.CompletedTask).ConfigureAwait(false);
                     break;
@@ -298,6 +303,24 @@ namespace CryptoExchange.Net.Sockets
             _processState = ProcessState.Idle;
         }
 
+        private TimeSpan GetReconnectDelay()
+        {
+            if (_reconnectAttempt == 0)
+            {
+                // Means this is directly after disconnecting. Only delay if the last reconnect time is very recent
+                var sinceLastReconnect = DateTime.UtcNow - _lastReconnectTime;
+                if (sinceLastReconnect < TimeSpan.FromSeconds(5))
+                    return TimeSpan.FromSeconds(5) - sinceLastReconnect;
+
+                return TimeSpan.FromMilliseconds(1);
+            }
+
+            var delay = Parameters.ReconnectPolicy == ReconnectPolicy.FixedDelay ? Parameters.ReconnectInterval : TimeSpan.FromSeconds(Math.Pow(2, Math.Min(5, _reconnectAttempt)));
+            if (delay > TimeSpan.Zero)
+                return delay;
+            return TimeSpan.FromMilliseconds(1);
+        }
+
         /// <inheritdoc />
         public virtual void Send(int id, string data, int weight)
         {

CryptoExchange.Net/Sockets/Query.cs

@@ -19,11 +19,6 @@ namespace CryptoExchange.Net.Sockets
         /// </summary>
         public int Id { get; } = ExchangeHelpers.NextId();
 
-        /// <summary>
-        /// Can handle data
-        /// </summary>
-        public bool CanHandleData => true;
-
         /// <summary>
         /// Has this query been completed
         /// </summary>

CryptoExchange.Net/Sockets/SocketConnection.cs

@@ -443,7 +443,7 @@ namespace CryptoExchange.Net.Sockets
                 // 4. Get the listeners interested in this message
                 List<IMessageProcessor> processors;
                 lock (_listenersLock)
-                    processors = _listeners.Where(s => s.ListenerIdentifiers.Contains(listenId) && s.CanHandleData).ToList();
+                    processors = _listeners.Where(s => s.ListenerIdentifiers.Contains(listenId)).ToList();
 
                 if (processors.Count == 0)
                 {
@@ -451,7 +451,7 @@ namespace CryptoExchange.Net.Sockets
                     {
                         List<string> listenerIds;
                         lock (_listenersLock)
-                            listenerIds = _listeners.Where(l => l.CanHandleData).SelectMany(l => l.ListenerIdentifiers).ToList();
+                            listenerIds = _listeners.SelectMany(l => l.ListenerIdentifiers).ToList();
                         _logger.ReceivedMessageNotMatchedToAnyListener(SocketId, listenId, string.Join(",", listenerIds));
                         UnhandledMessage?.Invoke(_accessor);
                     }
@@ -478,6 +478,10 @@ namespace CryptoExchange.Net.Sockets
                         continue;
                     }
 
+                    if (processor is Subscription subscriptionProcessor && !subscriptionProcessor.Confirmed)
+                        // If this message is for this listener then it is automatically confirmed, even if the subscription is not (yet) confirmed
+                        subscriptionProcessor.Confirmed = true;
+
                     // 6. Deserialize the message
                     object? deserialized = null;
                     desCache?.TryGetValue(messageType, out deserialized);
@@ -861,6 +865,8 @@ namespace CryptoExchange.Net.Sockets
                     { 
                         subscription.HandleSubQueryResponse(subQuery.Response!);
                         waitEvent.Set();
+                        if (r.Result.Success)
+                            subscription.Confirmed = true;
                         return r.Result;
                     }));
                 }
@@ -870,9 +876,6 @@ namespace CryptoExchange.Net.Sockets
                     return taskList.First(t => !t.Result.Success).Result;
             }
 
-            foreach (var subscription in subList)
-                subscription.Confirmed = true;
-
             if (!_socket.IsOpen)
                 return new CallResult(new WebError("Socket not connected"));
 

CryptoExchange.Net/Sockets/Subscription.cs

@@ -18,11 +18,6 @@ namespace CryptoExchange.Net.Sockets
         /// </summary>
         public int Id { get; set; }
 
-        /// <summary>
-        /// Can handle data
-        /// </summary>
-        public bool CanHandleData => Confirmed || HandleUpdatesBeforeConfirmation;
-
         /// <summary>
         /// Total amount of invocations
         /// </summary>
@@ -43,11 +38,6 @@ namespace CryptoExchange.Net.Sockets
         /// </summary>
         public bool Confirmed { get; set; }
 
-        /// <summary>
-        /// Whether this subscription should handle update messages before confirmation
-        /// </summary>
-        public bool HandleUpdatesBeforeConfirmation { get; set; }
-
         /// <summary>
         /// Is the subscription closed
         /// </summary>