From 51496fe1490df40ce61da57f4a6b8216aa894d57 Mon Sep 17 00:00:00 2001
From: Peter Kurhajec <61538034+PTKu@users.noreply.github.com>
Date: Tue, 12 Sep 2023 08:09:26 +0200
Subject: [PATCH] fixes an issue when async call may deadlock the connector
 (#221)

---
 .../AXSharp.Connector.S71500.WebAPI/WebApiConnector.cs | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/AXSharp.connectors/src/AXSharp.Connector.S71500.WebAPI/WebApiConnector.cs b/src/AXSharp.connectors/src/AXSharp.Connector.S71500.WebAPI/WebApiConnector.cs
index 266685ba..69640e63 100644
--- a/src/AXSharp.connectors/src/AXSharp.Connector.S71500.WebAPI/WebApiConnector.cs
+++ b/src/AXSharp.connectors/src/AXSharp.Connector.S71500.WebAPI/WebApiConnector.cs
@@ -111,7 +111,7 @@ private ApiHttpClientRequestHandler RequestHandler
 
     private readonly object concurentCountMutex = new object();
 
-    private void AntiThrottling(IEnumerable<ITwinPrimitive> primitives)
+    private async Task AntiThrottling(IEnumerable<ITwinPrimitive> primitives)
     {
         var concurrent = 0;
 
@@ -124,9 +124,7 @@ private void AntiThrottling(IEnumerable<ITwinPrimitive> primitives)
 
             if (concurrent >= ConcurrentRequestMaxCount)
             {
-                // We need this to be like it is to effectively prevent throttling over WebAPI
-                // `async awaiting` degrades overall comm performance.
-                Task.Delay(ConcurrentRequestDelay).Wait();
+                await Task.Delay(ConcurrentRequestDelay);
             }
 
         } while (concurrent >= ConcurrentRequestMaxCount);
@@ -277,7 +275,7 @@ public override async Task ReadBatchAsync(IEnumerable<ITwinPrimitive>? primitive
                             $"{((OnlinerBase)p).Symbol} | pollings: [{string.Join(";", ((OnlinerBase)p).PollingHolders.Select(a => a.Key.ToString()))}]")));
             }
 
-            AntiThrottling(primitives);
+            await AntiThrottling(primitives);
 
             var webApiPrimitives = twinPrimitives.Cast<IWebApiPrimitive>().Distinct().ToArray();
            
@@ -342,7 +340,7 @@ public override async Task WriteBatchAsync(IEnumerable<ITwinPrimitive>? primitiv
 
         try
         {
-            AntiThrottling(primitives);
+            await AntiThrottling(primitives);
 
             var responseData = new ApiBulkResponse();
             var twinPrimitives = primitives as ITwinPrimitive[] ?? primitives.ToArray();