Allow user properties as pre-encoded UTF-8 binary buffer (#2228)

* Add support for binary user properties in MQTT 5.0

* Optimize byte array reversal in SubscriptionTopicHashTests

* Use InvariantCulture for topic string conversion in Load_Tests

* switched to `Microsoft.Testing.Platform`

* Refactor CI workflow to separate signed and unsigned package builds

* Add condition to sign job to prevent execution on external pull requests

* Remove fallback to value as string in MqttUserProperty

* Refactor MqttUserProperty handling to use byte arrays for improved performance and add deprecation warnings for legacy methods

Source/MQTTnet.Tests/Clients/MqttClient/MqttClient_Connection_Tests.cs

@@ -6,6 +6,7 @@ using System.Text;
 using MQTTnet.Exceptions;
 using MQTTnet.Formatter;
 using MQTTnet.Internal;
+using MQTTnet.Packets;
 using MQTTnet.Protocol;
 using MQTTnet.Server;
 using MQTTnet.Server.EnhancedAuthentication;
@@ -143,7 +144,7 @@ public sealed class MqttClient_Connection_Tests : BaseTestClass
 
         var client = await testEnvironment.ConnectClient();
 
-        var disconnectOptions = testEnvironment.ClientFactory.CreateClientDisconnectOptionsBuilder().WithUserProperty("test_name", "test_value").Build();
+        var disconnectOptions = testEnvironment.ClientFactory.CreateClientDisconnectOptionsBuilder().WithUserProperty("test_name", Encoding.UTF8.GetBytes("test_value")).Build();
 
         // Perform a clean disconnect.
         await client.DisconnectAsync(disconnectOptions);
@@ -154,7 +155,7 @@ public sealed class MqttClient_Connection_Tests : BaseTestClass
         Assert.IsNotNull(eventArgs.UserProperties);
         Assert.HasCount(1, eventArgs.UserProperties);
         Assert.AreEqual("test_name", eventArgs.UserProperties[0].Name);
-        Assert.AreEqual("test_value", eventArgs.UserProperties[0].Value);
+        Assert.AreEqual("test_value", eventArgs.UserProperties[0].ReadValueAsString());
     }
 
     sealed class TestClientKerberosAuthenticationHandler : IMqttEnhancedAuthenticationHandler
@@ -260,7 +261,7 @@ public sealed class MqttClient_Connection_Tests : BaseTestClass
 
         server.ValidatingConnectionAsync += args =>
         {
-            args.ResponseUserProperties = [new("Property", "Value")];
+            args.ResponseUserProperties = [new("Property", Encoding.UTF8.GetBytes("Value"))];
 
             args.ReasonCode = MqttConnectReasonCode.QuotaExceeded;
 
@@ -274,7 +275,7 @@ public sealed class MqttClient_Connection_Tests : BaseTestClass
         Assert.IsNotNull(response);
         Assert.AreEqual(MqttClientConnectResultCode.QuotaExceeded, response.ResultCode);
         Assert.AreEqual("Property", response.UserProperties[0].Name);
-        Assert.AreEqual("Value", response.UserProperties[0].Value);
+        Assert.AreEqual("Value", response.UserProperties[0].ReadValueAsString());
     }
 
     [TestMethod]

Source/MQTTnet.Tests/Formatter/MqttPacketSerialization_V3_Tests.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Buffers;
+using System.Text;
 using MQTTnet.Exceptions;
 using MQTTnet.Formatter;
 using MQTTnet.Packets;
@@ -45,7 +46,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             SubscriptionIdentifiersAvailable = true,
             TopicAliasMaximum = 963,
             WildcardSubscriptionAvailable = true,
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(connAckPacket, MqttProtocolVersion.V311);
@@ -96,7 +97,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             SubscriptionIdentifiersAvailable = true,
             TopicAliasMaximum = 963,
             WildcardSubscriptionAvailable = true,
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(connAckPacket, MqttProtocolVersion.V310);
@@ -152,8 +153,8 @@ public sealed class MqttPacketSerialization_V3_Tests
             WillResponseTopic = "WillResponseTopic",
             WillMessageExpiryInterval = 542,
             WillPayloadFormatIndicator = MqttPayloadFormatIndicator.CharacterData,
-            UserProperties = [new("Foo", "Bar")],
-            WillUserProperties = [new("WillFoo", "WillBar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))],
+            WillUserProperties = [new("WillFoo", Encoding.UTF8.GetBytes("WillBar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(connectPacket, MqttProtocolVersion.V311);
@@ -195,7 +196,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             ReasonString = "ReasonString",
             ServerReference = "ServerReference",
             SessionExpiryInterval = 234,
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(disconnectPacket, MqttProtocolVersion.V311);
@@ -235,7 +236,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             PacketIdentifier = 123,
             ReasonCode = MqttPubAckReasonCode.NoMatchingSubscribers,
             ReasonString = "ReasonString",
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(pubAckPacket, MqttProtocolVersion.V311);
@@ -254,7 +255,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             PacketIdentifier = 123,
             ReasonCode = MqttPubCompReasonCode.PacketIdentifierNotFound,
             ReasonString = "ReasonString",
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(pubCompPacket, MqttProtocolVersion.V311);
@@ -284,7 +285,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             SubscriptionIdentifiers = [123],
             MessageExpiryInterval = 38,
             PayloadFormatIndicator = MqttPayloadFormatIndicator.CharacterData,
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(publishPacket, MqttProtocolVersion.V311);
@@ -313,7 +314,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             PacketIdentifier = 123,
             ReasonCode = MqttPubRecReasonCode.UnspecifiedError,
             ReasonString = "ReasonString",
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(pubRecPacket, MqttProtocolVersion.V311);
@@ -333,7 +334,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             PacketIdentifier = 123,
             ReasonCode = MqttPubRelReasonCode.PacketIdentifierNotFound,
             ReasonString = "ReasonString",
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(pubRelPacket, MqttProtocolVersion.V311);
@@ -353,7 +354,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             PacketIdentifier = 123,
             ReasonString = "ReasonString",
             ReasonCodes = [MqttSubscribeReasonCode.GrantedQoS1],
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(subAckPacket, MqttProtocolVersion.V311);
@@ -383,7 +384,7 @@ public sealed class MqttPacketSerialization_V3_Tests
                     QualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce
                 }
             ],
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(subscribePacket, MqttProtocolVersion.V311);
@@ -407,7 +408,7 @@ public sealed class MqttPacketSerialization_V3_Tests
             PacketIdentifier = 123,
             ReasonCodes = [MqttUnsubscribeReasonCode.ImplementationSpecificError],
             ReasonString = "ReasonString",
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(unsubAckPacket, MqttProtocolVersion.V311);
@@ -425,7 +426,7 @@ public sealed class MqttPacketSerialization_V3_Tests
         {
             PacketIdentifier = 123,
             TopicFilters = ["TopicFilter1"],
-            UserProperties = [new("Foo", "Bar")]
+            UserProperties = [new("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(unsubscribePacket, MqttProtocolVersion.V311);

Source/MQTTnet.Tests/Formatter/MqttPacketSerialization_V5_Tests.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Buffers;
+using System.Text;
 using MQTTnet.Formatter;
 using MQTTnet.Packets;
 using MQTTnet.Protocol;
@@ -32,7 +33,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             AuthenticationMethod = "AuthenticationMethod",
             ReasonCode = MqttAuthenticateReasonCode.ContinueAuthentication,
             ReasonString = "ReasonString",
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(authPacket, MqttProtocolVersion.V500);
@@ -68,7 +69,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             SubscriptionIdentifiersAvailable = true,
             TopicAliasMaximum = 963,
             WildcardSubscriptionAvailable = true,
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(connAckPacket, MqttProtocolVersion.V500);
@@ -124,8 +125,8 @@ public sealed class MqttPacketSerialization_V5_Tests
             WillResponseTopic = "WillResponseTopic",
             WillMessageExpiryInterval = 542,
             WillPayloadFormatIndicator = MqttPayloadFormatIndicator.CharacterData,
-            UserProperties = [new MqttUserProperty("Foo", "Bar")],
-            WillUserProperties = [new MqttUserProperty("WillFoo", "WillBar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))],
+            WillUserProperties = [new MqttUserProperty("WillFoo", Encoding.UTF8.GetBytes("WillBar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(connectPacket, MqttProtocolVersion.V500);
@@ -167,7 +168,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             ReasonString = "ReasonString",
             ServerReference = "ServerReference",
             SessionExpiryInterval = 234,
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(disconnectPacket, MqttProtocolVersion.V500);
@@ -207,7 +208,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             PacketIdentifier = 123,
             ReasonCode = MqttPubAckReasonCode.NoMatchingSubscribers,
             ReasonString = "ReasonString",
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(pubAckPacket, MqttProtocolVersion.V500);
@@ -226,7 +227,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             PacketIdentifier = 123,
             ReasonCode = MqttPubCompReasonCode.PacketIdentifierNotFound,
             ReasonString = "ReasonString",
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(pubCompPacket, MqttProtocolVersion.V500);
@@ -255,7 +256,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             SubscriptionIdentifiers = [123],
             MessageExpiryInterval = 38,
             PayloadFormatIndicator = MqttPayloadFormatIndicator.CharacterData,
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(publishPacket, MqttProtocolVersion.V500);
@@ -284,7 +285,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             PacketIdentifier = 123,
             ReasonCode = MqttPubRecReasonCode.UnspecifiedError,
             ReasonString = "ReasonString",
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(pubRecPacket, MqttProtocolVersion.V500);
@@ -303,7 +304,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             PacketIdentifier = 123,
             ReasonCode = MqttPubRelReasonCode.PacketIdentifierNotFound,
             ReasonString = "ReasonString",
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(pubRelPacket, MqttProtocolVersion.V500);
@@ -322,7 +323,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             PacketIdentifier = 123,
             ReasonString = "ReasonString",
             ReasonCodes = [MqttSubscribeReasonCode.GrantedQoS1],
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(subAckPacket, MqttProtocolVersion.V500);
@@ -352,7 +353,7 @@ public sealed class MqttPacketSerialization_V5_Tests
                     QualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce
                 }
             ],
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(subscribePacket, MqttProtocolVersion.V500);
@@ -376,7 +377,7 @@ public sealed class MqttPacketSerialization_V5_Tests
             PacketIdentifier = 123,
             ReasonCodes = [MqttUnsubscribeReasonCode.ImplementationSpecificError],
             ReasonString = "ReasonString",
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(unsubAckPacket, MqttProtocolVersion.V500);
@@ -395,7 +396,7 @@ public sealed class MqttPacketSerialization_V5_Tests
         {
             PacketIdentifier = 123,
             TopicFilters = ["TopicFilter1"],
-            UserProperties = [new MqttUserProperty("Foo", "Bar")]
+            UserProperties = [new MqttUserProperty("Foo", Encoding.UTF8.GetBytes("Bar"))]
         };
 
         var deserialized = MqttPacketSerializationHelper.EncodeAndDecodePacket(unsubscribePacket, MqttProtocolVersion.V500);

Source/MQTTnet.Tests/MQTTnet.Tests.csproj

@@ -6,13 +6,12 @@
         <LangVersion>default</LangVersion>
         <Nullable>disable</Nullable>
         <NoWarn>$(NoWarn);CA1707</NoWarn>
+        <EnableMSTestRunner>true</EnableMSTestRunner>
     </PropertyGroup>
 
     <ItemGroup>
         <PackageReference Include="Microsoft.IO.RecyclableMemoryStream" Version="3.0.1" />
-        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
-        <PackageReference Include="MSTest" Version="4.0.1" />
-
+        <PackageReference Include="MSTest" Version="4.0.2" />
         <FrameworkReference Include="Microsoft.AspNetCore.App" />
     </ItemGroup>
 
@@ -24,4 +23,10 @@
         <ProjectReference Include="..\MQTTnet.Extensions.TopicTemplate\MQTTnet.Extensions.TopicTemplate.csproj" />
     </ItemGroup>
 
+
+    <ItemGroup>
+    <None Include=".\..\..\global.json"
+            Link="global.json"
+            CopyToOutputDirectory="PreserveNewest"/>
+    </ItemGroup>
 </Project>

Source/MQTTnet.Tests/MQTTv5/Client_Tests.cs

@@ -4,6 +4,7 @@
 
 using System.Buffers;
 using System.Diagnostics.CodeAnalysis;
+using System.Text;
 using Microsoft.IO;
 using MQTTnet.Formatter;
 using MQTTnet.Internal;
@@ -64,8 +65,8 @@ public sealed class Client_Tests : BaseTestClass
         await client.PublishAsync(
             new MqttApplicationMessageBuilder().WithTopic("a")
                 .WithPayload("x")
-                .WithUserProperty("a", "1")
-                .WithUserProperty("b", "2")
+                .WithUserProperty("a", Encoding.UTF8.GetBytes("1"))
+                .WithUserProperty("b", Encoding.UTF8.GetBytes("2"))
                 .WithPayloadFormatIndicator(MqttPayloadFormatIndicator.CharacterData)
                 .WithQualityOfServiceLevel(MqttQualityOfServiceLevel.AtLeastOnce)
                 .Build());
@@ -98,8 +99,8 @@ public sealed class Client_Tests : BaseTestClass
         var applicationMessage = new MqttApplicationMessageBuilder().WithTopic("Hello")
             .WithPayload("World")
             .WithQualityOfServiceLevel(MqttQualityOfServiceLevel.AtMostOnce)
-            .WithUserProperty("x", "1")
-            .WithUserProperty("y", "2")
+            .WithUserProperty("x", Encoding.UTF8.GetBytes("1"))
+            .WithUserProperty("y", Encoding.UTF8.GetBytes("2"))
             .WithResponseTopic("response")
             .WithContentType("text")
             .WithMessageExpiryInterval(50)
@@ -214,8 +215,8 @@ public sealed class Client_Tests : BaseTestClass
         var applicationMessage = new MqttApplicationMessageBuilder().WithTopic("Hello")
             .WithPayload("World")
             .WithQualityOfServiceLevel(MqttQualityOfServiceLevel.AtMostOnce)
-            .WithUserProperty("x", "1")
-            .WithUserProperty("y", "2")
+            .WithUserProperty("x", Encoding.UTF8.GetBytes("1"))
+            .WithUserProperty("y", Encoding.UTF8.GetBytes("2"))
             .WithResponseTopic("response")
             .WithContentType("text")
             .WithMessageExpiryInterval(50)
@@ -250,8 +251,8 @@ public sealed class Client_Tests : BaseTestClass
         var applicationMessage = new MqttApplicationMessageBuilder().WithTopic("Hello")
             .WithPayload(memoryStream.GetReadOnlySequence())
             .WithQualityOfServiceLevel(MqttQualityOfServiceLevel.AtMostOnce)
-            .WithUserProperty("x", "1")
-            .WithUserProperty("y", "2")
+            .WithUserProperty("x", Encoding.UTF8.GetBytes("1"))
+            .WithUserProperty("y", Encoding.UTF8.GetBytes("2"))
             .WithResponseTopic("response")
             .WithContentType("text")
             .WithMessageExpiryInterval(50)

Source/MQTTnet.Tests/MqttApplicationMessageBuilder_Tests.cs

@@ -2,7 +2,12 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
+using System.Collections.Generic;
 using System.Text;
+using MQTTnet.Formatter;
+using MQTTnet.Formatter.V5;
+using MQTTnet.Packets;
 using MQTTnet.Protocol;
 
 namespace MQTTnet.Tests;
@@ -59,4 +64,64 @@ public sealed class MqttApplicationMessageBuilder_Tests
         Assert.IsTrue(message.Retain);
         Assert.AreEqual(MqttQualityOfServiceLevel.ExactlyOnce, message.QualityOfServiceLevel);
     }
+
+    [TestMethod]
+    public void CreateApplicationMessage_UserProperty_ReadOnlyMemoryValue()
+    {
+        var value = "utf8";
+        var buffer = Encoding.UTF8.GetBytes(value);
+
+        var message = new MqttApplicationMessageBuilder().WithTopic("topic").WithUserProperty("name", buffer.AsMemory()).Build();
+
+        Assert.IsNotNull(message.UserProperties);
+        Assert.HasCount(1, message.UserProperties);
+
+        var userProperty = message.UserProperties[0];
+        CollectionAssert.AreEqual(buffer, userProperty.ValueBuffer.ToArray());
+        Assert.AreEqual(value, userProperty.ReadValueAsString());
+    }
+
+    [TestMethod]
+    public void CreateApplicationMessage_UserProperty_ArraySegmentValue()
+    {
+        var buffer = Encoding.UTF8.GetBytes("segment");
+        var segment = new ArraySegment<byte>(buffer);
+
+        var message = new MqttApplicationMessageBuilder().WithTopic("topic").WithUserProperty("name", segment).Build();
+
+        Assert.IsNotNull(message.UserProperties);
+        Assert.HasCount(1, message.UserProperties);
+
+        var userProperty = message.UserProperties[0];
+        CollectionAssert.AreEqual(buffer, userProperty.ValueBuffer.ToArray());
+        Assert.AreEqual("segment", userProperty.ReadValueAsString());
+    }
+
+    [TestMethod]
+    public void WriteUserProperty_FromBinaryBuffer_EqualsStringEncoding()
+    {
+        var name = "name";
+        var value = "value";
+        var encoded = Encoding.UTF8.GetBytes(value);
+
+        var binaryWriter = new MqttBufferWriter(32, 256);
+        var binaryPropertiesWriter = new MqttV5PropertiesWriter(binaryWriter);
+        binaryPropertiesWriter.WriteUserProperties(new List<MqttUserProperty> { new(name, encoded.AsMemory()) });
+
+        var stringWriter = new MqttBufferWriter(32, 256);
+        var stringPropertiesWriter = new MqttV5PropertiesWriter(stringWriter);
+#pragma warning disable CS0618 // Type or member is obsolete
+        stringPropertiesWriter.WriteUserProperties(new List<MqttUserProperty> { new(name, value) });
+#pragma warning restore CS0618 // Type or member is obsolete
+
+        CollectionAssert.AreEqual(GetWrittenBytes(stringWriter), GetWrittenBytes(binaryWriter));
+    }
+
+    static byte[] GetWrittenBytes(MqttBufferWriter writer)
+    {
+        var length = writer.Length;
+        var copy = new byte[length];
+        Array.Copy(writer.GetBuffer(), copy, length);
+        return copy;
+    }
 }

Source/MQTTnet.Tests/MqttApplicationMessageValidator_Tests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Text;
 using MQTTnet.Formatter;
 
 namespace MQTTnet.Tests;
@@ -27,7 +28,7 @@ public sealed class MqttApplicationMessageValidator_Tests
     public void Succeed_When_Using_UserProperties_And_MQTT_500()
     {
         MqttApplicationMessageValidator.ThrowIfNotSupported(
-            new MqttApplicationMessageBuilder().WithTopic("A").WithUserProperty("User", "Property").Build(),
+            new MqttApplicationMessageBuilder().WithTopic("A").WithUserProperty("User", Encoding.UTF8.GetBytes("Property")).Build(),
             MqttProtocolVersion.V500);
     }
 
@@ -35,7 +36,7 @@ public sealed class MqttApplicationMessageValidator_Tests
     public void Succeed_When_Using_WillUserProperties_And_MQTT_311()
     {
         Assert.ThrowsExactly<NotSupportedException>(() => MqttApplicationMessageValidator.ThrowIfNotSupported(
-            new MqttApplicationMessageBuilder().WithTopic("B").WithUserProperty("User", "Property").Build(),
+            new MqttApplicationMessageBuilder().WithTopic("B").WithUserProperty("User", Encoding.UTF8.GetBytes("Property")).Build(),
             MqttProtocolVersion.V311));
     }
 }

Source/MQTTnet.Tests/MqttClientOptionsValidator_Tests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Text;
 using MQTTnet.Formatter;
 
 namespace MQTTnet.Tests;
@@ -13,27 +14,27 @@ public sealed class MqttClientOptionsValidator_Tests
     [TestMethod]
     public void Succeed_When_Using_UserProperties_And_MQTT_500()
     {
-        new MqttClientOptionsBuilder().WithProtocolVersion(MqttProtocolVersion.V500).WithUserProperty("User", "Property").WithTcpServer("FAKE").Build();
+        new MqttClientOptionsBuilder().WithProtocolVersion(MqttProtocolVersion.V500).WithUserProperty("User", Encoding.UTF8.GetBytes("Property")).WithTcpServer("FAKE").Build();
     }
 
     [TestMethod]
     public void Succeed_When_Using_WillUserProperties_And_MQTT_311()
     {
         Assert.ThrowsExactly<NotSupportedException>(() =>
-            new MqttClientOptionsBuilder().WithProtocolVersion(MqttProtocolVersion.V311).WithWillUserProperty("User", "Property").WithTcpServer("FAKE").Build());
+            new MqttClientOptionsBuilder().WithProtocolVersion(MqttProtocolVersion.V311).WithWillUserProperty("User", Encoding.UTF8.GetBytes("Property")).WithTcpServer("FAKE").Build());
     }
 
     [TestMethod]
     public void Succeed_When_Using_WillUserProperties_And_MQTT_500()
     {
-        new MqttClientOptionsBuilder().WithProtocolVersion(MqttProtocolVersion.V500).WithWillUserProperty("User", "Property").WithTcpServer("FAKE").Build();
+        new MqttClientOptionsBuilder().WithProtocolVersion(MqttProtocolVersion.V500).WithWillUserProperty("User", Encoding.UTF8.GetBytes("Property")).WithTcpServer("FAKE").Build();
     }
 
     [TestMethod]
     public void Throw_When_Using_UserProperties_And_MQTT_311()
     {
         Assert.ThrowsExactly<NotSupportedException>(() =>
-            new MqttClientOptionsBuilder().WithProtocolVersion(MqttProtocolVersion.V311).WithUserProperty("User", "Property").WithTcpServer("FAKE").Build());
+            new MqttClientOptionsBuilder().WithProtocolVersion(MqttProtocolVersion.V311).WithUserProperty("User", Encoding.UTF8.GetBytes("Property")).WithTcpServer("FAKE").Build());
     }
 
     [TestMethod]

Source/MQTTnet.Tests/MqttTcpChannel_Tests.cs

@@ -20,7 +20,8 @@ public class MqttTcpChannel_Tests
 
         try
         {
-            serverSocket.Bind(new IPEndPoint(IPAddress.Any, 50001));
+            serverSocket.Bind(new IPEndPoint(IPAddress.Loopback, 0));
+            var serverPort = ((IPEndPoint)serverSocket.LocalEndPoint).Port;
             serverSocket.Listen(0);
 
 #pragma warning disable 4014
@@ -37,7 +38,7 @@ public class MqttTcpChannel_Tests
                 },
                 ct.Token);
 
-            var remoteEndPoint = new DnsEndPoint("localhost", 50001);
+            var remoteEndPoint = new DnsEndPoint("localhost", serverPort);
             using var clientSocket = new CrossPlatformSocket(AddressFamily.InterNetwork, ProtocolType.Tcp);
             await clientSocket.ConnectAsync(remoteEndPoint, CancellationToken.None);
 

Source/MQTTnet.Tests/Server/Cross_Version_Tests.cs

@@ -43,7 +43,7 @@ public sealed class Cross_Version_Tests : BaseTestClass
 
         var applicationMessage = new MqttApplicationMessageBuilder().WithTopic("My/Message")
             .WithPayload("My_Payload")
-            .WithUserProperty("A", "B")
+            .WithUserProperty("A", Encoding.UTF8.GetBytes("B"))
             .WithResponseTopic("Response")
             .WithCorrelationData(Encoding.UTF8.GetBytes("Correlation"))
             .Build();

Source/MQTTnet.Tests/Server/HotSwapCerts_Tests.cs

@@ -2,6 +2,7 @@ using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Net;
 using System.Net.Security;
+using System.Net.Sockets;
 using System.Security.Authentication;
 using System.Security.Cryptography;
 using System.Security.Cryptography.X509Certificates;
@@ -26,6 +27,7 @@ public sealed class HotSwapCerts_Tests
         using var client01 = new ClientTestHarness();
         server.InstallNewClientCert(client01.GetCurrentClientCert());
         client01.InstallNewServerCert(server.GetCurrentServerCert());
+        client01.SetServerPort(server.EncryptedPort);
 
         await server.StartServer();
 
@@ -47,6 +49,7 @@ public sealed class HotSwapCerts_Tests
         using var client01 = new ClientTestHarness();
         server.InstallNewClientCert(client01.GetCurrentClientCert());
         client01.InstallNewServerCert(server.GetCurrentServerCert());
+        client01.SetServerPort(server.EncryptedPort);
 
         await server.StartServer();
 
@@ -70,6 +73,7 @@ public sealed class HotSwapCerts_Tests
         using var client01 = new ClientTestHarness();
         server.InstallNewClientCert(client01.GetCurrentClientCert());
         client01.InstallNewServerCert(server.GetCurrentServerCert());
+        client01.SetServerPort(server.EncryptedPort);
 
         await server.StartServer();
         await client01.Connect();
@@ -91,6 +95,7 @@ public sealed class HotSwapCerts_Tests
         using var client01 = new ClientTestHarness();
         server.InstallNewClientCert(client01.GetCurrentClientCert());
         client01.InstallNewServerCert(server.GetCurrentServerCert());
+        client01.SetServerPort(server.EncryptedPort);
 
         await server.StartServer();
         await client01.Connect();
@@ -135,10 +140,11 @@ public sealed class HotSwapCerts_Tests
     sealed class ClientTestHarness : IDisposable
     {
         readonly HotSwappableClientCertProvider _hotSwapClient = new HotSwappableClientCertProvider();
+        int _serverPort = 8883;
 
         IMqttClient _client;
 
-        public string ClientId => _client.Options.ClientId;
+        public string ClientId => _client?.Options?.ClientId;
 
         public Task Connect()
         {
@@ -147,10 +153,15 @@ public sealed class HotSwapCerts_Tests
 
         public void Dispose()
         {
-            _client.Dispose();
+            _client?.Dispose();
             _hotSwapClient.Dispose();
         }
 
+        public void SetServerPort(int port)
+        {
+            _serverPort = port;
+        }
+
         public X509Certificate2 GetCurrentClientCert()
         {
             var result = _hotSwapClient.GetCertificates()[0];
@@ -216,7 +227,7 @@ public sealed class HotSwapCerts_Tests
                     o => o.WithClientCertificatesProvider(_hotSwapClient)
                         .WithCertificateValidationHandler(_hotSwapClient.OnCertificateValidation)
                         .WithSslProtocols(SslProtocols.Tls12))
-                .WithTcpServer("localhost")
+                .WithTcpServer("localhost", _serverPort)
                 .WithCleanSession()
                 .WithProtocolVersion(MqttProtocolVersion.V500);
 
@@ -242,6 +253,7 @@ public sealed class HotSwapCerts_Tests
     sealed class ServerTestHarness : IDisposable
     {
         readonly HotSwappableServerCertProvider _hotSwapServer = new HotSwappableServerCertProvider();
+        readonly int _encryptedPort = GetFreeTcpPort();
 
         MqttServer _server;
 
@@ -261,6 +273,8 @@ public sealed class HotSwapCerts_Tests
             return _server.DisconnectClientAsync(client.ClientId, MqttDisconnectReasonCode.UnspecifiedError);
         }
 
+        public int EncryptedPort => _encryptedPort;
+
         public X509Certificate2 GetCurrentServerCert()
         {
             return _hotSwapServer.GetCertificate();
@@ -281,6 +295,7 @@ public sealed class HotSwapCerts_Tests
             var mqttServerFactory = new MqttServerFactory();
 
             var mqttServerOptions = new MqttServerOptionsBuilder().WithEncryptionCertificate(_hotSwapServer)
+                .WithEncryptedEndpointPort(_encryptedPort)
                 .WithRemoteCertificateValidationCallback(_hotSwapServer.RemoteCertificateValidationCallback)
                 .WithEncryptedEndpoint()
                 .Build();
@@ -290,6 +305,17 @@ public sealed class HotSwapCerts_Tests
             _server = mqttServerFactory.CreateMqttServer(mqttServerOptions);
             return _server.StartAsync();
         }
+
+        static int GetFreeTcpPort()
+        {
+            var listener = new TcpListener(IPAddress.Loopback, 0);
+            listener.Start();
+
+            var port = ((IPEndPoint)listener.LocalEndpoint).Port;
+            listener.Stop();
+
+            return port;
+        }
     }
 
     sealed class HotSwappableClientCertProvider : IMqttClientCertificatesProvider, IDisposable

Source/MQTTnet.Tests/Server/Subscribe_Tests.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Globalization;
+using System.Text;
 using MQTTnet.Exceptions;
 using MQTTnet.Formatter;
 using MQTTnet.Internal;
@@ -98,7 +99,7 @@ public sealed class Subscribe_Tests : BaseTestClass
 
         var client = await testEnvironment.ConnectClient();
 
-        var subscribeOptions = testEnvironment.ClientFactory.CreateSubscribeOptionsBuilder().WithTopicFilter("X").WithUserProperty("A", "1").Build();
+        var subscribeOptions = testEnvironment.ClientFactory.CreateSubscribeOptionsBuilder().WithTopicFilter("X").WithUserProperty("A", Encoding.UTF8.GetBytes("1")).Build();
         await client.SubscribeAsync(subscribeOptions);
 
         CollectionAssert.AreEqual(subscribeOptions.UserProperties.ToList(), eventArgs.UserProperties);

Source/MQTTnet.Tests/Server/Subscription_TopicHash_Tests.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using System.Linq;
 using System.Text;
 using MQTTnet.Packets;
 using MQTTnet.Protocol;

Source/MQTTnet.Tests/Server/Unsubscribe_Tests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Text;
 using MQTTnet.Exceptions;
 using MQTTnet.Formatter;
 using MQTTnet.Internal;
@@ -45,7 +46,7 @@ public sealed class Unsubscribe_Tests : BaseTestClass
 
         var client = await testEnvironment.ConnectClient();
 
-        var unsubscribeOptions = testEnvironment.ClientFactory.CreateUnsubscribeOptionsBuilder().WithTopicFilter("X").WithUserProperty("A", "1").Build();
+        var unsubscribeOptions = testEnvironment.ClientFactory.CreateUnsubscribeOptionsBuilder().WithTopicFilter("X").WithUserProperty("A", Encoding.UTF8.GetBytes("1")).Build();
         await client.UnsubscribeAsync(unsubscribeOptions);
 
         CollectionAssert.AreEqual(unsubscribeOptions.UserProperties.ToList(), eventArgs.UserProperties);

Source/MQTTnet.Tests/Server/User_Properties_Tests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Text;
 using MQTTnet.Formatter;
 using MQTTnet.Internal;
 using MQTTnet.Packets;
@@ -26,10 +27,10 @@ public class Feature_Tests
 
         var message = new MqttApplicationMessageBuilder()
             .WithTopic("A")
-            .WithUserProperty("x", "1")
-            .WithUserProperty("y", "2")
-            .WithUserProperty("z", "3")
-            .WithUserProperty("z", "4"); // z is here two times to test list of items
+            .WithUserProperty("x", Encoding.UTF8.GetBytes("1"))
+            .WithUserProperty("y", Encoding.UTF8.GetBytes("2"))
+            .WithUserProperty("z", Encoding.UTF8.GetBytes("3"))
+            .WithUserProperty("z", Encoding.UTF8.GetBytes("4")); // z is here two times to test list of items
 
         await receiver.SubscribeAsync(new MqttClientSubscribeOptions
         {