feat: Add cancellation to ConnectAsync()

VisconFactoryIntelligence · Jun 15, 2023 · bea5b4c · bea5b4c
1 parent 4ff22fe
commit bea5b4c
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Showing 4 changed files with 29 additions and 11 deletions.
diff --git a/src/AdsClient/Ams.cs b/src/AdsClient/Ams.cs
@@ -40,9 +40,9 @@ public Ams(IAmsSocket amsSocket)
         /// </summary>
         public ushort AmsPortSource { get; set; } = 32905;
 
-        public Task ConnectAsync()
+        public Task ConnectAsync(CancellationToken cancellationToken = default)
         {
-            return AmsSocket.ConnectAsync(new MessageHandler(this));
+            return AmsSocket.ConnectAsync(new MessageHandler(this), cancellationToken);
         }
 
         public void Dispose()

diff --git a/src/AdsClient/AmsSocket.cs b/src/AdsClient/AmsSocket.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Net.Sockets;
+using System.Threading;
 using System.Threading.Tasks;
 using Viscon.Communication.Ads.Internal;
 
@@ -31,11 +32,25 @@ public void Close()
             connection?.Close();
         }
 
-        public async Task ConnectAsync(IIncomingMessageHandler messageHandler)
+        public async Task ConnectAsync(IIncomingMessageHandler messageHandler, CancellationToken cancellationToken = default)
         {
             if (connection is not null) throw new InvalidOperationException("Connection was already established.");
 
-            await TcpClient.ConnectAsync(Host, Port).ConfigureAwait(false);
+            using (cancellationToken.Register(state => ((Socket)state).Close(), Socket))
+            {
+                try
+                {
+                    await TcpClient.ConnectAsync(Host, Port).ConfigureAwait(false);
+                }
+                catch (Exception) when (cancellationToken.IsCancellationRequested)
+                {
+                    // The exception handling is quite generic, but exceptions thrown differ across target frameworks.
+                    // (See https://stackoverflow.com/a/66656805/1085457)
+                    // This is probably not something to worry about, since apparently cancellation was requested anyway.
+                    cancellationToken.ThrowIfCancellationRequested();
+                }
+            }
+
             connection = new AmsSocketConnection(TcpClient.Client, messageHandler);
         }
 

diff --git a/src/AdsClient/IAmsSocket.cs b/src/AdsClient/IAmsSocket.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Viscon.Communication.Ads
@@ -9,7 +10,7 @@ public interface IAmsSocket
 
         void Close();
 
-        Task ConnectAsync(IIncomingMessageHandler messageHandler);
+        Task ConnectAsync(IIncomingMessageHandler messageHandler, CancellationToken cancellationToken = default);
 
         Task SendAsync(byte[] message);
 

diff --git a/test/AdsClient/AdsCommandsAsyncTest.cs b/test/AdsClient/AdsCommandsAsyncTest.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using FakeItEasy;
 using Shouldly;
@@ -18,12 +19,13 @@ public class AdsCommandsAsyncTest : IDisposable
 
         public AdsCommandsAsyncTest()
         {
-            A.CallTo(() => amsSocket.ConnectAsync(A<IIncomingMessageHandler>.Ignored)).ReturnsLazily(call =>
-            {
-                messageHandler = call.GetArgument<IIncomingMessageHandler>(0);
-                connected = true;
-                return Task.CompletedTask;
-            });
+            A.CallTo(() => amsSocket.ConnectAsync(A<IIncomingMessageHandler>.Ignored, A<CancellationToken>.Ignored))
+                .ReturnsLazily(call =>
+                {
+                    messageHandler = call.GetArgument<IIncomingMessageHandler>(0);
+                    connected = true;
+                    return Task.CompletedTask;
+                });
             A.CallTo(() => amsSocket.Connected).ReturnsLazily(() => connected);
 
             client = new AdsClient(amsNetIdSource: "10.0.0.120.1.1", amsSocket: amsSocket,