Added better support for subscriptions without subscribe confirmation

CryptoExchange.Net/Clients/SocketApiClient.cs

@@ -270,7 +270,7 @@ namespace CryptoExchange.Net.Clients
             }
 
             var waitEvent = new AsyncResetEvent(false);
-            var subQuery = subscription.GetSubQuery(socketConnection);
+            var subQuery = subscription.CreateSubscriptionQuery(socketConnection);
             if (subQuery != null)
             {
                 // Send the request and wait for answer

CryptoExchange.Net/Objects/Enums.cs

@@ -251,4 +251,20 @@ namespace CryptoExchange.Net.Objects
         /// </summary>
         DEX
     }
+
+    /// <summary>
+    /// Timeout behavior for queries
+    /// </summary>
+    public enum TimeoutBehavior
+    {
+        /// <summary>
+        /// Fail the request
+        /// </summary>
+        Fail,
+        /// <summary>
+        /// Mark the query as successful
+        /// </summary>
+        Succeed
+    }
+
 }

CryptoExchange.Net/Sockets/Query.cs

@@ -29,6 +29,11 @@ namespace CryptoExchange.Net.Sockets
         /// </summary>
         public TimeSpan? RequestTimeout { get; set; }
 
+        /// <summary>
+        /// What should happen if the query times out
+        /// </summary>
+        public TimeoutBehavior TimeoutBehavior { get; set; } = TimeoutBehavior.Fail;
+
         /// <summary>
         /// The number of required responses. Can be more than 1 when for example subscribing multiple symbols streams in a single request,
         /// and each symbol receives it's own confirmation response
@@ -183,7 +188,7 @@ namespace CryptoExchange.Net.Sockets
         /// <inheritdoc />
         public override async Task<CallResult> Handle(SocketConnection connection, DataEvent<object> message, MessageHandlerLink check)
         {
-            if (!PreCheckMessage(message))
+            if (!PreCheckMessage(connection, message))
                 return CallResult.SuccessResult;
 
             CurrentResponses++;
@@ -208,9 +213,7 @@ namespace CryptoExchange.Net.Sockets
         /// <summary>
         /// Validate if a message is actually processable by this query
         /// </summary>
-        /// <param name="message"></param>
+        public virtual bool PreCheckMessage(SocketConnection connection, DataEvent<object> message) => true;
-        /// <returns></returns>
-        public virtual bool PreCheckMessage(DataEvent<object> message) => true;
 
         /// <inheritdoc />
         public override void Timeout()
@@ -219,7 +222,11 @@ namespace CryptoExchange.Net.Sockets
                 return;
                         
             Completed = true;
-            Result = new CallResult<THandlerResponse>(new TimeoutError());
+            if (TimeoutBehavior == TimeoutBehavior.Fail)
+                Result = new CallResult<THandlerResponse>(new TimeoutError());
+            else
+                Result = new CallResult<THandlerResponse>(default, null, default);
+
             ContinueAwaiter?.Set();
             _event.Set();
         }

CryptoExchange.Net/Sockets/SocketConnection.cs

@@ -202,6 +202,18 @@ namespace CryptoExchange.Net.Sockets
             }
         }
 
+        /// <summary>
+        /// The number of current pending requests
+        /// </summary>
+        public int PendingRequests
+        {
+            get
+            {
+                lock (_listenersLock)
+                    return _listeners.OfType<Query>().Where(x => !x.Completed).Count();
+            }
+        }
+
         private bool _pausedActivity;
         private readonly object _listenersLock;
         private readonly List<IMessageProcessor> _listeners;
@@ -519,7 +531,10 @@ namespace CryptoExchange.Net.Sockets
                         {
                             // If this message is for this listener then it is automatically confirmed, even if the subscription is not (yet) confirmed
                             subscriptionProcessor.Confirmed = true;
-                            // This doesn't trigger a waiting subscribe query, should probably also somehow set the wait event for that
+                            if (subscriptionProcessor.SubscriptionQuery?.TimeoutBehavior == TimeoutBehavior.Succeed)
+                                // If this subscription has a query waiting for a timeout (success if there is no error response)
+                                // then time it out now as the data is being received, so we assume it's successful
+                                subscriptionProcessor.SubscriptionQuery.Timeout();
                         }
 
                         // 5. Deserialize the message
@@ -996,7 +1011,7 @@ namespace CryptoExchange.Net.Sockets
                         return result;
                     }
 
-                    var subQuery = subscription.GetSubQuery(this);
+                    var subQuery = subscription.CreateSubscriptionQuery(this);
                     if (subQuery == null)
                     {
                         subscription.IsResubscribing = false;
@@ -1031,7 +1046,7 @@ namespace CryptoExchange.Net.Sockets
 
         internal async Task UnsubscribeAsync(Subscription subscription)
         {
-            var unsubscribeRequest = subscription.GetUnsubQuery();
+            var unsubscribeRequest = subscription.CreateUnsubscriptionQuery(this);
             if (unsubscribeRequest == null)
                 return;
 
@@ -1044,7 +1059,7 @@ namespace CryptoExchange.Net.Sockets
             if (!_socket.IsOpen)
                 return new CallResult(new WebError("Socket is not connected"));
 
-            var subQuery = subscription.GetSubQuery(this);
+            var subQuery = subscription.CreateSubscriptionQuery(this);
             if (subQuery == null)
                 return CallResult.SuccessResult;
 

CryptoExchange.Net/Sockets/Subscription.cs

@@ -80,6 +80,16 @@ namespace CryptoExchange.Net.Sockets
         /// </summary>
         public string? Topic { get; set; }
 
+        /// <summary>
+        /// The subscribe query for this subscription
+        /// </summary>
+        public Query? SubscriptionQuery { get; private set; }
+
+        /// <summary>
+        /// The unsubscribe query for this subscription
+        /// </summary>
+        public Query? UnsubscriptionQuery { get; private set; }
+
         /// <summary>
         /// ctor
         /// </summary>
@@ -91,11 +101,21 @@ namespace CryptoExchange.Net.Sockets
             Id = ExchangeHelpers.NextId();
         }
 
+        /// <summary>
+        /// Create a new subscription query
+        /// </summary>
+        public Query? CreateSubscriptionQuery(SocketConnection connection)
+        {
+            var query = GetSubQuery(connection);
+            SubscriptionQuery = query;
+            return query;
+        }
+
         /// <summary>
         /// Get the subscribe query to send when subscribing
         /// </summary>
         /// <returns></returns>
-        public abstract Query? GetSubQuery(SocketConnection connection);
+        protected abstract Query? GetSubQuery(SocketConnection connection);
 
         /// <summary>
         /// Handle a subscription query response
@@ -109,11 +129,21 @@ namespace CryptoExchange.Net.Sockets
         /// <param name="message"></param>
         public virtual void HandleUnsubQueryResponse(object message) { }
 
+        /// <summary>
+        /// Create a new unsubscription query
+        /// </summary>
+        public Query? CreateUnsubscriptionQuery(SocketConnection connection)
+        {
+            var query = GetUnsubQuery(connection);
+            UnsubscriptionQuery = query;
+            return query;
+        }
+
         /// <summary>
         /// Get the unsubscribe query to send when unsubscribing
         /// </summary>
         /// <returns></returns>
-        public abstract Query? GetUnsubQuery();
+        protected abstract Query? GetUnsubQuery(SocketConnection connection);
 
         /// <inheritdoc />
         public virtual CallResult<object> Deserialize(IMessageAccessor message, Type type) => message.Deserialize(type);

CryptoExchange.Net/Sockets/SystemSubscription.cs

@@ -22,9 +22,9 @@ namespace CryptoExchange.Net.Sockets
         }
 
         /// <inheritdoc />
-        public override Query? GetSubQuery(SocketConnection connection) => null;
+        protected override Query? GetSubQuery(SocketConnection connection) => null;
 
         /// <inheritdoc />
-        public override Query? GetUnsubQuery() => null;
+        protected override Query? GetUnsubQuery(SocketConnection connection) => null;
     }
 }