Improve PingAsync timeout handling.

.github/workflows/ReleaseNotes.md

@@ -1,4 +1,5 @@
 * [Core] MQTT Packets being sent over web socket transport are now setting the web socket frame boundaries correctly (#1499).
 * [Client] Keep alive mechanism now uses the configured timeout value from the options (thanks to @Stannieman, #1495).
+* [Client] The _PingAsync_ will fallback to the timeout specified in the client options when the cancellation token cannot be cancelled.
 * [Server] A DISCONNECT packet is no longer sent to MQTT clients < 5.0.0 (thanks to @logicaloud, #1506).
 * [Server] Improved "take over" process handling.

Samples/Client/Client_Connection_Samples.cs

@@ -321,14 +321,12 @@ public static class Client_Connection_Samples
                     {
                         try
                         {
-                            // This code will also do the very first connect! So no call to _ConnectAsync_ is required
+                            // This code will also do the very first connect! So no call to _ConnectAsync_ is required in the first place.
-                            // in the first place.
+                            if (!await mqttClient.TryPingAsync())
-                            if (!mqttClient.IsConnected)
                             {
                                 await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
 
                                 // Subscribe to topics when session is clean etc.
-
                                 Console.WriteLine("The MQTT client is connected.");
                             }
                         }

Source/MQTTnet.Tests/Client/MqttClient_Tests.cs

@@ -19,10 +19,12 @@ using MQTTnet.Packets;
 using MQTTnet.Protocol;
 using MQTTnet.Tests.Mockups;
 
+// ReSharper disable InconsistentNaming
+
 namespace MQTTnet.Tests.Client
 {
     [TestClass]
-    public sealed class Client_Tests : BaseTestClass
+    public sealed class MqttClient_Tests : BaseTestClass
     {
         [DataTestMethod]
         [DataRow(MqttQualityOfServiceLevel.ExactlyOnce)]
@@ -145,6 +147,7 @@ namespace MQTTnet.Tests.Client
                 }
                 catch
                 {
+                    // Ignore errors.
                 }
 
                 await Task.Delay(500);
@@ -239,10 +242,10 @@ namespace MQTTnet.Tests.Client
 
                 for (var i = 0; i < 98; i++)
                 {
-                    Assert.IsFalse(clients[i].IsConnected, $"clients[{i}] is not connected");
+                    Assert.IsFalse(clients[i].TryPingAsync().GetAwaiter().GetResult(), $"clients[{i}] is not connected");
                 }
 
-                Assert.IsTrue(clients[99].IsConnected);
+                Assert.IsTrue(clients[99].TryPingAsync().GetAwaiter().GetResult());
 
                 Assert.AreEqual(1, clientStatus.Count);
                 Assert.AreEqual(1, sessionStatus.Count);
@@ -332,7 +335,7 @@ namespace MQTTnet.Tests.Client
 
                 var client = await testEnvironment.ConnectClient();
 
-                Assert.IsTrue(client.IsConnected);
+                Assert.IsTrue(client.TryPingAsync().GetAwaiter().GetResult());
             }
         }
 
@@ -343,11 +346,11 @@ namespace MQTTnet.Tests.Client
             {
                 await testEnvironment.StartServer();
                 var client = await testEnvironment.ConnectClient();
-                Assert.IsTrue(client.IsConnected);
+                Assert.IsTrue(client.TryPingAsync().GetAwaiter().GetResult());
 
                 await client.DisconnectAsync();
 
-                Assert.IsFalse(client.IsConnected);
+                Assert.IsFalse(client.TryPingAsync().GetAwaiter().GetResult());
             }
         }
 
@@ -591,17 +594,17 @@ namespace MQTTnet.Tests.Client
                 var client = await testEnvironment.ConnectClient();
 
                 await Task.Delay(500);
-                Assert.IsTrue(client.IsConnected);
+                Assert.IsTrue(await client.TryPingAsync());
 
                 await server.StopAsync();
                 await Task.Delay(500);
-                Assert.IsFalse(client.IsConnected);
+                Assert.IsFalse(await client.TryPingAsync());
 
                 await server.StartAsync();
                 await Task.Delay(500);
 
                 await client.ConnectAsync(new MqttClientOptionsBuilder().WithTcpServer("127.0.0.1", testEnvironment.ServerPort).Build());
-                Assert.IsTrue(client.IsConnected);
+                Assert.IsTrue(await client.TryPingAsync());
             }
         }
 
@@ -637,6 +640,7 @@ namespace MQTTnet.Tests.Client
                 }
                 catch
                 {
+                    // Ignore errors.
                 }
 
                 SpinWait.SpinUntil(() => tries >= maxTries, 10000);
@@ -656,11 +660,11 @@ namespace MQTTnet.Tests.Client
                 var client = await testEnvironment.ConnectClient();
 
                 await Task.Delay(500);
-                Assert.IsTrue(client.IsConnected);
+                Assert.IsTrue(client.TryPingAsync().GetAwaiter().GetResult());
 
                 await server.StopAsync();
                 await Task.Delay(500);
-                Assert.IsFalse(client.IsConnected);
+                Assert.IsFalse(client.TryPingAsync().GetAwaiter().GetResult());
 
                 for (var i = 0; i < 5; i++)
                 {
@@ -671,6 +675,7 @@ namespace MQTTnet.Tests.Client
                     }
                     catch
                     {
+                        // Ignore errors.
                     }
                 }
 
@@ -678,7 +683,7 @@ namespace MQTTnet.Tests.Client
                 await Task.Delay(500);
 
                 await client.ConnectAsync(new MqttClientOptionsBuilder().WithTcpServer("127.0.0.1", testEnvironment.ServerPort).Build());
-                Assert.IsTrue(client.IsConnected);
+                await client.PingAsync();
             }
         }
 
@@ -828,10 +833,10 @@ namespace MQTTnet.Tests.Client
         {
             using (var testEnvironment = new TestEnvironment(TestContext))
             {
-                var server = await testEnvironment.StartServer();
+                await testEnvironment.StartServer();
                 var client = await testEnvironment.ConnectClient();
 
-                Assert.IsTrue(client.IsConnected);
+                Assert.IsTrue(client.TryPingAsync().GetAwaiter().GetResult());
                 client.DisconnectedAsync += e =>
                 {
                     Assert.IsTrue(e.ClientWasConnected);
@@ -851,7 +856,7 @@ namespace MQTTnet.Tests.Client
                 var server = await testEnvironment.StartServer();
                 var client = await testEnvironment.ConnectClient();
 
-                Assert.IsTrue(client.IsConnected);
+                Assert.IsTrue(client.TryPingAsync().GetAwaiter().GetResult());
                 client.DisconnectedAsync += e =>
                 {
                     Assert.IsTrue(e.ClientWasConnected);
@@ -941,7 +946,7 @@ namespace MQTTnet.Tests.Client
                 await Task.Delay(500);
 
                 Assert.IsTrue(messageReceived);
-                Assert.IsTrue(client1.IsConnected);
+                Assert.IsTrue(client1.TryPingAsync().GetAwaiter().GetResult());
                 Assert.IsFalse(disconnectedFired);
             }
         }

Source/MQTTnet/Client/IMqttClient.cs

@@ -7,32 +7,31 @@ namespace MQTTnet.Client
 {
     public interface IMqttClient : IDisposable
     {
-        event Func<MqttClientConnectedEventArgs, Task> ConnectedAsync;
-        
-        event Func<MqttClientConnectingEventArgs, Task> ConnectingAsync;
-        
-        event Func<MqttClientDisconnectedEventArgs, Task> DisconnectedAsync;
-        
         event Func<MqttApplicationMessageReceivedEventArgs, Task> ApplicationMessageReceivedAsync;
-        
+        event Func<MqttClientConnectedEventArgs, Task> ConnectedAsync;
+
+        event Func<MqttClientConnectingEventArgs, Task> ConnectingAsync;
+
+        event Func<MqttClientDisconnectedEventArgs, Task> DisconnectedAsync;
+
         event Func<InspectMqttPacketEventArgs, Task> InspectPackage;
-        
+
         bool IsConnected { get; }
-        
+
         MqttClientOptions Options { get; }
-        
+
         Task<MqttClientConnectResult> ConnectAsync(MqttClientOptions options, CancellationToken cancellationToken = default);
-        
+
         Task DisconnectAsync(MqttClientDisconnectOptions options, CancellationToken cancellationToken = default);
-        
+
         Task PingAsync(CancellationToken cancellationToken = default);
-        
+
-        Task SendExtendedAuthenticationExchangeDataAsync(MqttExtendedAuthenticationExchangeData data, CancellationToken cancellationToken = default);
-        
-        Task<MqttClientSubscribeResult> SubscribeAsync(MqttClientSubscribeOptions options, CancellationToken cancellationToken = default);
-        
-        Task<MqttClientUnsubscribeResult> UnsubscribeAsync(MqttClientUnsubscribeOptions options, CancellationToken cancellationToken = default);
-        
         Task<MqttClientPublishResult> PublishAsync(MqttApplicationMessage applicationMessage, CancellationToken cancellationToken = default);
+
+        Task SendExtendedAuthenticationExchangeDataAsync(MqttExtendedAuthenticationExchangeData data, CancellationToken cancellationToken = default);
+
+        Task<MqttClientSubscribeResult> SubscribeAsync(MqttClientSubscribeOptions options, CancellationToken cancellationToken = default);
+
+        Task<MqttClientUnsubscribeResult> UnsubscribeAsync(MqttClientUnsubscribeOptions options, CancellationToken cancellationToken = default);
     }
 }

Source/MQTTnet/Client/MqttClientExtensions.cs

@@ -14,6 +14,26 @@ namespace MQTTnet.Client
 {
     public static class MqttClientExtensions
     {
+        public static async Task<bool> TryPingAsync(this IMqttClient client, CancellationToken cancellationToken = default)
+        {
+            if (client == null)
+            {
+                throw new ArgumentNullException(nameof(client));
+            }
+
+            try
+            {
+                await client.PingAsync(cancellationToken).ConfigureAwait(false);
+                return true;
+            }
+            catch
+            {
+                // Ignore errors.
+            }
+
+            return false;
+        }
+        
         public static Task DisconnectAsync(this IMqttClient client, MqttClientDisconnectReason reason = MqttClientDisconnectReason.NormalDisconnection, string reasonString = null)
         {
             if (client == null)