Add .NET 7, 8, trimming and AOT support

Also fixed several nullability warnings.

Signed-off-by: Giovanni Bassi <giggio@giggio.net>

.github/workflows/build.yml

@@ -1,6 +1,7 @@
 name: Build
 
 on:
+  workflow_dispatch:
   push:
     branches:
     - main
@@ -15,15 +16,15 @@ jobs:
 
     steps:
     - name: Check out our repo
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         submodules: true
 
     # Build with .NET 6.0 SDK
-    - name: Setup .NET 6.0
+    - name: Setup .NET 8.0
       uses: actions/setup-dotnet@v3
       with:
-        dotnet-version: 6.0.x
+        dotnet-version: 8.0.x
 
     - name: Build
       run: |

.github/workflows/nuget.yml

@@ -13,7 +13,7 @@ jobs:
 
     steps:
     - name: Check out our repo
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         submodules: true
 
@@ -21,7 +21,7 @@ jobs:
     - name: Setup .NET 6.0
       uses: actions/setup-dotnet@v3
       with:
-        dotnet-version: 6.0.x
+        dotnet-version: 8.0.x
 
     - name: Build
       run: |

CloudEvents.sln

@@ -72,6 +72,12 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "xml", "xml", "{4012C753-68D
 		conformance\format\xml\valid-events.xml = conformance\format\xml\valid-events.xml
 	EndProjectSection
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "HttpSendJson", "samples\HttpSendJson\HttpSendJson.csproj", "{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "samples", "samples", "{5AD5E051-9A8E-46D9-B0C5-8933718C6D1F}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CloudNative.CloudEvents.MinApiSample", "samples\CloudNative.CloudEvents.MinApiSample\CloudNative.CloudEvents.MinApiSample.csproj", "{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -238,15 +244,43 @@ Global
 		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Release|x64.Build.0 = Release|Any CPU
 		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Release|x86.ActiveCfg = Release|Any CPU
 		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Release|x86.Build.0 = Release|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Debug|x64.Build.0 = Debug|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Debug|x86.Build.0 = Debug|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Release|x64.ActiveCfg = Release|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Release|x64.Build.0 = Release|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Release|x86.ActiveCfg = Release|Any CPU
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8}.Release|x86.Build.0 = Release|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Debug|x64.Build.0 = Debug|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Debug|x86.Build.0 = Debug|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Release|Any CPU.Build.0 = Release|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Release|x64.ActiveCfg = Release|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Release|x64.Build.0 = Release|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Release|x86.ActiveCfg = Release|Any CPU
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
+		{F1B9B769-DB6B-481F-905C-24FE3B12E00E} = {5AD5E051-9A8E-46D9-B0C5-8933718C6D1F}
+		{9760D744-D1BF-40E3-BD6F-7F639BFB9188} = {5AD5E051-9A8E-46D9-B0C5-8933718C6D1F}
 		{A5906FBA-D73A-4A09-8539-CB10D7B586AE} = {8CCC98B3-1776-49FF-96D6-947A9E5DFB0A}
 		{D8055631-E6BB-4CD2-8162-F674D6D30E76} = {A5906FBA-D73A-4A09-8539-CB10D7B586AE}
 		{119AD438-878B-4383-BC9F-779F1605E711} = {A5906FBA-D73A-4A09-8539-CB10D7B586AE}
 		{4012C753-68DE-4737-936F-F5DBC485C51B} = {A5906FBA-D73A-4A09-8539-CB10D7B586AE}
+		{730D4C5E-DC5B-498C-ADFB-05CB81ECCEC8} = {5AD5E051-9A8E-46D9-B0C5-8933718C6D1F}
+		{1566A665-9FFF-4D87-9C7B-CC06C72C9BFF} = {5AD5E051-9A8E-46D9-B0C5-8933718C6D1F}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {F77A454C-CC17-4AD6-823A-64E1A94FDA0A}

samples/CloudNative.CloudEvents.MinApiSample/CloudNative.CloudEvents.MinApiSample.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\CloudNative.CloudEvents.AspNetCore\CloudNative.CloudEvents.AspNetCore.csproj" />
+    <ProjectReference Include="..\..\src\CloudNative.CloudEvents\CloudNative.CloudEvents.csproj" />
+    <ProjectReference Include="..\..\src\CloudNative.CloudEvents.SystemTextJson\CloudNative.CloudEvents.SystemTextJson.csproj" />
+  </ItemGroup>
+  <PropertyGroup Condition="'$(Configuration)'=='Release'">
+    <SelfContained>true</SelfContained>
+    <PublishAot>true</PublishAot>
+    <DebugType>None</DebugType>
+    <DebugSymbols>False</DebugSymbols>
+  </PropertyGroup>
+</Project>

samples/CloudNative.CloudEvents.MinApiSample/Program.cs

@@ -0,0 +1,85 @@
+// Copyright (c) Cloud Native Foundation.
+// Licensed under the Apache 2.0 license.
+// See LICENSE file in the project root for full license information.
+
+using CloudNative.CloudEvents;
+using CloudNative.CloudEvents.Http;
+using CloudNative.CloudEvents.SystemTextJson;
+using CloudNative.CloudEvents.AspNetCore;
+using System.Text.Json.Serialization;
+using System.Text.Json;
+using System.Text;
+
+var builder = WebApplication.CreateBuilder(args);
+var app = builder.Build();
+var formatter = new JsonEventFormatter<Message>(MyJsonContext.Default);
+
+app.MapPost("/api/events/receive/", async (HttpRequest request) =>
+{
+    var cloudEvent = await request.ToCloudEventAsync(formatter);
+    using var ms = new MemoryStream();
+    using var writer = new Utf8JsonWriter(ms, new() { Indented = true });
+    writer.WriteStartObject();
+    foreach (var (attribute, value) in cloudEvent.GetPopulatedAttributes())
+        writer.WriteString(attribute.Name, attribute.Format(value));
+    writer.WriteEndObject();
+    await writer.FlushAsync();
+    var attributeMap = Encoding.UTF8.GetString(ms.ToArray());
+    return Results.Text($"Received event with ID {cloudEvent.Id}, attributes: {attributeMap}");
+});
+
+app.MapPost("/api/events/receive2/", (Event e) => Results.Json(e.CloudEvent.Data, MyJsonContext.Default));
+
+app.MapPost("/api/events/receive3/", (Message message) => Results.Json(message, MyJsonContext.Default));
+
+app.MapGet("/api/events/generate/", () =>
+{
+    var evt = new CloudEvent
+    {
+        Type = "CloudNative.CloudEvents.MinApiSample",
+        Source = new Uri("https://github.com/cloudevents/sdk-csharp"),
+        Time = DateTimeOffset.Now,
+        DataContentType = "application/json",
+        Id = Guid.NewGuid().ToString(),
+        Data = new Message("C#", Environment.Version.ToString())
+    };
+    // Format the event as the body of the response. This is UTF-8 JSON because of
+    // the CloudEventFormatter we're using, but EncodeStructuredModeMessage always
+    // returns binary data. We could return the data directly, but for debugging
+    // purposes it's useful to have the JSON string.
+    var bytes = formatter.EncodeStructuredModeMessage(evt, out var contentType);
+    string json = Encoding.UTF8.GetString(bytes.Span);
+    // Specify the content type of the response: this is what makes it a CloudEvent.
+    // (In "binary mode", the content type is the content type of the data, and headers
+    // indicate that it's a CloudEvent.)
+    return Results.Content(json, contentType.MediaType, Encoding.UTF8);
+});
+
+app.Run();
+
+[JsonSerializable(typeof(Message))]
+internal partial class MyJsonContext : JsonSerializerContext { }
+
+public class Event
+{
+    private readonly static JsonEventFormatter formatter = new JsonEventFormatter<Message>(MyJsonContext.Default);
+    // required for receive2
+    public static async ValueTask<Event?> BindAsync(HttpContext context)
+    {
+        var cloudEvent = await context.Request.ToCloudEventAsync(formatter);
+        return new Event { CloudEvent = cloudEvent };
+    }
+    public required CloudEvent CloudEvent { get; init; }
+}
+
+record class Message(string Language, string EnvironmentVersion)
+{
+    private readonly static JsonEventFormatter formatter = new JsonEventFormatter<Message>(MyJsonContext.Default);
+    // required for receive3
+    public static async ValueTask<Message?> BindAsync(HttpContext context)
+    {
+        var cloudEvent = await context.Request.ToCloudEventAsync(formatter);
+        return cloudEvent.Data is Message message ? message : null;
+    }
+}
+

samples/CloudNative.CloudEvents.MinApiSample/Properties/launchSettings.json

@@ -0,0 +1,14 @@
+{
+  "profiles": {
+    "http": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "launchUrl": "api/events/generate",
+      "applicationUrl": "http://localhost:5002",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

samples/CloudNative.CloudEvents.MinApiSample/appsettings.Development.json

@@ -0,0 +1,8 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  }
+}

samples/CloudNative.CloudEvents.MinApiSample/appsettings.json

@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*"
+}

samples/Directory.Build.props

@@ -14,5 +14,6 @@
     
     <!-- Never pack any sample projects -->
     <IsPackable>False</IsPackable>
+    <LangVersion>12.0</LangVersion>
   </PropertyGroup>
 </Project>

samples/HttpSendJson/HttpSendJson.csproj

@@ -0,0 +1,19 @@
+<Project Sdk="Microsoft.NET.Sdk">
+	<PropertyGroup>
+		<OutputType>Exe</OutputType>
+		<TargetFramework>net8.0</TargetFramework>
+		<Nullable>enable</Nullable>
+		<ImplicitUsings>enable</ImplicitUsings>
+	</PropertyGroup>
+	<ItemGroup>
+		<PackageReference Include="docopt.net" Version="0.8.1" />
+		<ProjectReference Include="..\..\src\CloudNative.CloudEvents\CloudNative.CloudEvents.csproj" />
+		<ProjectReference Include="..\..\src\CloudNative.CloudEvents.SystemTextJson\CloudNative.CloudEvents.SystemTextJson.csproj" />
+	</ItemGroup>
+	<PropertyGroup Condition="'$(Configuration)'=='Release'">
+		<SelfContained>true</SelfContained>
+		<PublishAot>true</PublishAot>
+		<DebugType>None</DebugType>
+		<DebugSymbols>False</DebugSymbols>
+	</PropertyGroup>
+</Project>

samples/HttpSendJson/Program.cs

@@ -0,0 +1,70 @@
+// Copyright (c) Cloud Native Foundation.
+// Licensed under the Apache 2.0 license.
+// See LICENSE file in the project root for full license information.
+
+using CloudNative.CloudEvents;
+using CloudNative.CloudEvents.Http;
+using CloudNative.CloudEvents.SystemTextJson;
+using DocoptNet;
+using System.Net.Mime;
+using static System.Console;
+
+// This application uses the docopt.net library for parsing the command
+// line and calling the application code.
+ProgramArguments programArguments = new();
+var result = await ProgramArguments.CreateParserWithVersion()
+.Parse(args)
+.Match(RunAsync,
+    result => { WriteLine(result.Help); return Task.FromResult(1); },
+    result => { WriteLine(result.Version); return Task.FromResult(0); },
+    result => { Error.WriteLine(result.Usage); return Task.FromResult(1); });
+return result;
+
+static async Task<int> RunAsync(ProgramArguments args)
+{
+    var cloudEvent = new CloudEvent
+    {
+        Id = Guid.NewGuid().ToString(),
+        Type = args.OptType,
+        Source = new Uri(args.OptSource),
+        DataContentType = MediaTypeNames.Application.Json,
+        Data = System.Text.Json.JsonSerializer.Serialize("hey there!", GeneratedJsonContext.Default.String)
+    };
+
+    var content = cloudEvent.ToHttpContent(ContentMode.Structured, new JsonEventFormatter(GeneratedJsonContext.Default));
+
+    var httpClient = new HttpClient();
+    // Your application remains in charge of adding any further headers or
+    // other information required to authenticate/authorize or otherwise
+    // dispatch the call at the server.
+    var result = await httpClient.PostAsync(args.OptUrl, content);
+
+    WriteLine(result.StatusCode);
+    return 0;
+}
+
+[System.Text.Json.Serialization.JsonSerializable(typeof(string))]
+internal partial class GeneratedJsonContext : System.Text.Json.Serialization.JsonSerializerContext
+{
+}
+
+[DocoptArguments]
+partial class ProgramArguments
+{
+    const string Help = @"HttpSendJson.
+
+    Usage:
+      HttpSendJson --url=URL [--type=TYPE] [--source=SOURCE]
+      HttpSendJson (-h | --help)
+      HttpSendJson --version
+
+    Options:
+      --url=URL                 HTTP(S) address to send the event to.
+      --type=TYPE               CloudEvents 'type' [default: com.example.myevent].
+      --source=SOURCE           CloudEvents 'source' [default: urn:example-com:mysource:abc].
+      -h --help                 Show this screen.
+      --version                 Show version.
+";
+    public static string Version => $"producer {typeof(ProgramArguments).Assembly.GetName().Version}";
+    public static IParser<ProgramArguments> CreateParserWithVersion() => CreateParser().WithVersion(Version);
+}

src/CloudNative.CloudEvents.Amqp/AmqpExtensions.cs

@@ -8,6 +8,7 @@ using Amqp.Types;
 using CloudNative.CloudEvents.Core;
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net.Mime;
 
@@ -145,7 +146,7 @@ namespace CloudNative.CloudEvents.Amqp
             }
         }
 
-        private static bool HasCloudEventsContentType(Message message, out string? contentType)
+        private static bool HasCloudEventsContentType(Message message, [NotNullWhen(true)] out string? contentType)
         {
             contentType = message.Properties.ContentType?.ToString();
             return MimeUtilities.IsCloudEventsContentType(contentType);
@@ -250,3 +251,22 @@ namespace CloudNative.CloudEvents.Amqp
         }
     }
 }
+
+#if NETSTANDARD2_0
+namespace System.Diagnostics.CodeAnalysis
+{
+    /// <summary>Specifies that when a method returns <see cref="ReturnValue"/>, the parameter will not be null even if the corresponding type allows it.</summary>
+    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+    internal sealed class NotNullWhenAttribute : Attribute
+    {
+        /// <summary>Initializes the attribute with the specified return value condition.</summary>
+        /// <param name="returnValue">
+        /// The return value condition. If the method returns this value, the associated parameter will not be null.
+        /// </param>
+        public NotNullWhenAttribute(bool returnValue) => ReturnValue = returnValue;
+
+        /// <summary>Gets the return value condition.</summary>
+        public bool ReturnValue { get; }
+    }
+}
+#endif

src/CloudNative.CloudEvents.Amqp/CloudNative.CloudEvents.Amqp.csproj

@@ -1,9 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0;net8.0</TargetFrameworks>
     <Description>AMQP extensions for CloudNative.CloudEvents</Description>
-    <LangVersion>8.0</LangVersion>
     <Nullable>enable</Nullable>
     <PackageTags>cncf;cloudnative;cloudevents;events;amqp</PackageTags>
   </PropertyGroup>

src/CloudNative.CloudEvents.AspNetCore/CloudNative.CloudEvents.AspNetCore.csproj

@@ -1,9 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0;net8.0</TargetFrameworks>
     <Description>ASP.Net Core extensions for CloudNative.CloudEvents</Description>
-    <LangVersion>8.0</LangVersion>
     <Nullable>enable</Nullable>
     <PackageTags>cncf;cloudnative;cloudevents;events;aspnetcore;aspnet</PackageTags>
   </PropertyGroup>

src/CloudNative.CloudEvents.Avro/AvroEventFormatter.cs

@@ -185,7 +185,7 @@ namespace CloudNative.CloudEvents.Avro
             // will fail and that's okay since the type is useless without the proper schema.
             using var sr = new StreamReader(typeof(AvroEventFormatter)
                 .Assembly
-                .GetManifestResourceStream("CloudNative.CloudEvents.Avro.AvroSchema.json"));
+                .GetManifestResourceStream("CloudNative.CloudEvents.Avro.AvroSchema.json")!);
 
             return (RecordSchema) Schema.Parse(sr.ReadToEnd());
         }

src/CloudNative.CloudEvents.Avro/CloudNative.CloudEvents.Avro.csproj

@@ -1,10 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0;net8.0</TargetFrameworks>
     <Description>Avro extensions for CloudNative.CloudEvents</Description>
     <PackageTags>cncf;cloudnative;cloudevents;events;avro</PackageTags>
-    <LangVersion>10.0</LangVersion>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 

src/CloudNative.CloudEvents.Kafka/CloudNative.CloudEvents.Kafka.csproj

@@ -1,10 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0;net8.0</TargetFrameworks>
     <Description>Kafka extensions for CloudNative.CloudEvents</Description>
     <PackageTags>cncf;cloudnative;cloudevents;events;kafka</PackageTags>
-    <LangVersion>8.0</LangVersion>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 

src/CloudNative.CloudEvents.Mqtt/CloudNative.CloudEvents.Mqtt.csproj

@@ -1,10 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0;net8.0</TargetFrameworks>
     <Description>MQTT extensions for CloudNative.CloudEvents</Description>
     <PackageTags>cncf;cloudnative;cloudevents;events;mqtt</PackageTags>
-    <LangVersion>8.0</LangVersion>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 

src/CloudNative.CloudEvents.NewtonsoftJson/CloudNative.CloudEvents.NewtonsoftJson.csproj

@@ -1,9 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0;net8.0</TargetFrameworks>
     <Description>JSON support for the CNCF CloudEvents SDK, based on Newtonsoft.Json.</Description>
-    <LangVersion>8.0</LangVersion>
     <Nullable>enable</Nullable>
     <PackageTags>cncf;cloudnative;cloudevents;events;json;newtonsoft</PackageTags>
   </PropertyGroup>

src/CloudNative.CloudEvents.NewtonsoftJson/JsonEventFormatter.cs

@@ -345,7 +345,9 @@ namespace CloudNative.CloudEvents.NewtonsoftJson
             {
                 throw new ArgumentException($"Structured mode property '{DataBase64PropertyName}' must be a string, when present.");
             }
-            cloudEvent.Data = Convert.FromBase64String((string?)dataBase64Token);
+            var tokenString = (string?)dataBase64Token;
+            if (tokenString != null)
+                cloudEvent.Data = Convert.FromBase64String(tokenString);
         }
 
         /// <summary>
@@ -524,7 +526,7 @@ namespace CloudNative.CloudEvents.NewtonsoftJson
             }
             else
             {
-                ContentType dataContentType = new ContentType(GetOrInferDataContentType(cloudEvent));
+                ContentType dataContentType = new ContentType(GetOrInferDataContentType(cloudEvent)!);
                 if (IsJsonMediaType(dataContentType.MediaType))
                 {
                     writer.WritePropertyName(DataPropertyName);
@@ -696,7 +698,7 @@ namespace CloudNative.CloudEvents.NewtonsoftJson
         /// <inheritdoc />
         protected override void EncodeStructuredModeData(CloudEvent cloudEvent, JsonWriter writer)
         {
-            T data = (T)cloudEvent.Data;
+            var data = (T?)cloudEvent.Data;
             writer.WritePropertyName(DataPropertyName);
             Serializer.Serialize(writer, data);
         }

src/CloudNative.CloudEvents.Protobuf/CloudNative.CloudEvents.Protobuf.csproj

@@ -1,10 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-	<TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+	<TargetFrameworks>netstandard2.0;netstandard2.1;net7.0;net8.0</TargetFrameworks>
 	<Description>Support for the Protobuf event format in for CloudNative.CloudEvents</Description>
 	<PackageTags>cncf;cloudnative;cloudevents;events;protobuf</PackageTags>
-	<LangVersion>10.0</LangVersion>
 	<Nullable>enable</Nullable>
   </PropertyGroup>
 

src/CloudNative.CloudEvents.SystemTextJson/CloudNative.CloudEvents.SystemTextJson.csproj

@@ -1,9 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0;net8.0</TargetFrameworks>
     <Description>JSON support for the CNCF CloudEvents SDK, based on System.Text.Json.</Description>
-    <LangVersion>8.0</LangVersion>
     <PackageTags>cncf;cloudnative;cloudevents;events;json;systemtextjson</PackageTags>
     <Nullable>enable</Nullable>
   </PropertyGroup>

src/CloudNative.CloudEvents.SystemTextJson/JsonEventFormatter.cs

@@ -5,10 +5,12 @@
 using CloudNative.CloudEvents.Core;
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net.Mime;
 using System.Text;
 using System.Text.Json;
+using System.Text.Json.Serialization;
 using System.Threading.Tasks;
 using System.Xml.Linq;
 
@@ -94,6 +96,13 @@ namespace CloudNative.CloudEvents.SystemTextJson
         /// </summary>
         protected const string DataPropertyName = "data";
 
+#if NET7_0_OR_GREATER
+        /// <summary>
+        /// Json serialization context used to serialize and enable trimming and AOT.
+        /// </summary>
+        protected readonly JsonSerializerContext? JsonSerializerContext;
+#endif
+
         /// <summary>
         /// The options to use when serializing objects to JSON.
         /// </summary>
@@ -108,22 +117,54 @@ namespace CloudNative.CloudEvents.SystemTextJson
         /// Creates a JsonEventFormatter that uses the default <see cref="JsonSerializerOptions"/>
         /// and <see cref="JsonDocumentOptions"/> for serializing and parsing.
         /// </summary>
+#if NET7_0_OR_GREATER
+        [RequiresUnreferencedCode("Use a constructor that takes a JsonSerializerContext.")]
+#endif
         public JsonEventFormatter() : this(null, default)
         {
         }
 
+#if NET7_0_OR_GREATER
+        /// <summary>
+        /// Creates a JsonEventFormatter that uses the default <see cref="JsonSerializerOptions"/>
+        /// and <see cref="JsonDocumentOptions"/> for serializing and parsing.
+        /// </summary>
+        /// <param name="jsonSerializerContext">The json context used for serializing objects to JSON.</param>
+        public JsonEventFormatter(JsonSerializerContext jsonSerializerContext) : this(default, jsonSerializerContext)
+        {
+        }
+#endif
+
         /// <summary>
         /// Creates a JsonEventFormatter that uses the specified <see cref="JsonSerializerOptions"/>
         /// and <see cref="JsonDocumentOptions"/> for serializing and parsing.
         /// </summary>
         /// <param name="serializerOptions">The options to use when serializing objects to JSON. May be null.</param>
         /// <param name="documentOptions">The options to use when parsing JSON documents.</param>
+#if NET7_0_OR_GREATER
+        [RequiresUnreferencedCode("Use a constructor that takes a JsonSerializerContext.")]
+#endif
         public JsonEventFormatter(JsonSerializerOptions? serializerOptions, JsonDocumentOptions documentOptions)
         {
             SerializerOptions = serializerOptions;
             DocumentOptions = documentOptions;
         }
 
+#if NET7_0_OR_GREATER
+        /// <summary>
+        /// Creates a JsonEventFormatter that uses the specified <see cref="JsonSerializerOptions"/>
+        /// and <see cref="JsonDocumentOptions"/> for serializing and parsing.
+        /// </summary>
+        /// <param name="documentOptions">The options to use when parsing JSON documents.</param>
+        /// <param name="jsonSerializerContext">The json context used for serializing objects to JSON.</param>
+        public JsonEventFormatter(JsonDocumentOptions documentOptions, JsonSerializerContext jsonSerializerContext)
+        {
+            Validation.CheckNotNull(jsonSerializerContext, nameof(jsonSerializerContext));
+            DocumentOptions = documentOptions;
+            JsonSerializerContext = jsonSerializerContext;
+        }
+#endif
+
         /// <inheritdoc />
         public override async Task<CloudEvent> DecodeStructuredModeMessageAsync(Stream body, ContentType? contentType, IEnumerable<CloudEventAttribute>? extensionAttributes) =>
             await DecodeStructuredModeMessageImpl(body, contentType, extensionAttributes, true).ConfigureAwait(false);
@@ -533,6 +574,10 @@ namespace CloudNative.CloudEvents.SystemTextJson
         /// <param name="cloudEvent">The CloudEvent being encoded, which will have a non-null value for
         /// its <see cref="CloudEvent.Data"/> property.
         /// <param name="writer"/>The writer to serialize the data to. Will not be null.</param>
+#if NET7_0_OR_GREATER
+        [UnconditionalSuppressMessage("Trimming", "IL2026:Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code", Justification = "Constructor already annotated.")]
+        [UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "Constructor already annotated.")]
+#endif
         protected virtual void EncodeStructuredModeData(CloudEvent cloudEvent, Utf8JsonWriter writer)
         {
             // Binary data is encoded using the data_base64 property, regardless of content type.
@@ -548,7 +593,12 @@ namespace CloudNative.CloudEvents.SystemTextJson
                 if (IsJsonMediaType(dataContentType.MediaType))
                 {
                     writer.WritePropertyName(DataPropertyName);
-                    JsonSerializer.Serialize(writer, cloudEvent.Data, SerializerOptions);
+#if NET7_0_OR_GREATER
+                    if (JsonSerializerContext != null)
+                        JsonSerializer.Serialize(writer, cloudEvent.Data, cloudEvent.Data!.GetType(), JsonSerializerContext);
+                    else
+#endif
+                        JsonSerializer.Serialize(writer, cloudEvent.Data, SerializerOptions);
                 }
                 else if (cloudEvent.Data is string text && dataContentType.MediaType.StartsWith("text/"))
                 {
@@ -564,6 +614,10 @@ namespace CloudNative.CloudEvents.SystemTextJson
         }
 
         /// <inheritdoc />
+#if NET7_0_OR_GREATER
+        [UnconditionalSuppressMessage("Trimming", "IL2026:Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code", Justification = "Constructor already annotated.")]
+        [UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "Constructor already annotated.")]
+#endif
         public override ReadOnlyMemory<byte> EncodeBinaryModeEventData(CloudEvent cloudEvent)
         {
             Validation.CheckCloudEventArgument(cloudEvent, nameof(cloudEvent));
@@ -584,10 +638,18 @@ namespace CloudNative.CloudEvents.SystemTextJson
                 var encoding = MimeUtilities.GetEncoding(contentType);
                 if (encoding is UTF8Encoding)
                 {
+#if NET7_0_OR_GREATER
+                    if (JsonSerializerContext != null)
+                        return JsonSerializer.SerializeToUtf8Bytes(cloudEvent.Data, cloudEvent.Data.GetType(), JsonSerializerContext);
+#endif
                     return JsonSerializer.SerializeToUtf8Bytes(cloudEvent.Data, SerializerOptions);
                 }
                 else
                 {
+#if NET7_0_OR_GREATER
+                    if (JsonSerializerContext != null)
+                        return MimeUtilities.GetEncoding(contentType).GetBytes(JsonSerializer.Serialize(cloudEvent.Data, cloudEvent.Data.GetType(), JsonSerializerContext));
+#endif
                     return MimeUtilities.GetEncoding(contentType).GetBytes(JsonSerializer.Serialize(cloudEvent.Data, SerializerOptions));
                 }
             }
@@ -654,22 +716,57 @@ namespace CloudNative.CloudEvents.SystemTextJson
         /// Creates a JsonEventFormatter that uses the default <see cref="JsonSerializerOptions"/>
         /// and <see cref="JsonDocumentOptions"/> for serializing and parsing.
         /// </summary>
+#if NET7_0_OR_GREATER
+        [RequiresUnreferencedCode("Use a constructor that takes a JsonSerializerContext.")]
+#endif
         public JsonEventFormatter()
         {
         }
 
+#if NET7_0_OR_GREATER
+        /// <summary>
+        /// Creates a JsonEventFormatter that uses the serializer <see cref="JsonSerializerOptions"/>
+        /// and <see cref="JsonDocumentOptions"/> for serializing and parsing.
+        /// </summary>
+        /// <param name="jsonSerializerContext">The json context used for serializing objects to JSON.</param>
+        public JsonEventFormatter(JsonSerializerContext jsonSerializerContext)
+            : base(default, jsonSerializerContext)
+        {
+        }
+#endif
+
         /// <summary>
         /// Creates a JsonEventFormatter that uses the serializer <see cref="JsonSerializerOptions"/>
         /// and <see cref="JsonDocumentOptions"/> for serializing and parsing.
         /// </summary>
         /// <param name="serializerOptions">The options to use when serializing and parsing. May be null.</param>
         /// <param name="documentOptions">The options to use when parsing JSON documents.</param>
+#if NET7_0_OR_GREATER
+        [RequiresUnreferencedCode("Use a constructor that takes a JsonSerializerContext.")]
+#endif
         public JsonEventFormatter(JsonSerializerOptions serializerOptions, JsonDocumentOptions documentOptions)
             : base(serializerOptions, documentOptions)
         {
         }
 
+#if NET7_0_OR_GREATER
+        /// <summary>
+        /// Creates a JsonEventFormatter that uses the serializer <see cref="JsonSerializerOptions"/>
+        /// and <see cref="JsonDocumentOptions"/> for serializing and parsing.
+        /// </summary>
+        /// <param name="documentOptions">The options to use when parsing JSON documents.</param>
+        /// <param name="jsonSerializerContext">The json context used for serializing objects to JSON.</param>
+        public JsonEventFormatter(JsonDocumentOptions documentOptions, JsonSerializerContext jsonSerializerContext)
+            : base(documentOptions, jsonSerializerContext)
+        {
+        }
+#endif
+
         /// <inheritdoc />
+#if NET7_0_OR_GREATER
+        [UnconditionalSuppressMessage("Trimming", "IL2026:Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code", Justification = "Constructor already annotated.")]
+        [UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "Constructor already annotated.")]
+#endif
         public override ReadOnlyMemory<byte> EncodeBinaryModeEventData(CloudEvent cloudEvent)
         {
             Validation.CheckCloudEventArgument(cloudEvent, nameof(cloudEvent));
@@ -679,10 +776,18 @@ namespace CloudNative.CloudEvents.SystemTextJson
                 return Array.Empty<byte>();
             }
             T data = (T)cloudEvent.Data;
+#if NET7_0_OR_GREATER
+            if (JsonSerializerContext != null)
+                return JsonSerializer.SerializeToUtf8Bytes(data, data.GetType(), JsonSerializerContext);
+#endif
             return JsonSerializer.SerializeToUtf8Bytes(data, SerializerOptions);
         }
 
         /// <inheritdoc />
+#if NET7_0_OR_GREATER
+        [UnconditionalSuppressMessage("Trimming", "IL2026:Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code", Justification = "Constructor already annotated.")]
+        [UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "Constructor already annotated.")]
+#endif
         public override void DecodeBinaryModeEventData(ReadOnlyMemory<byte> body, CloudEvent cloudEvent)
         {
             Validation.CheckNotNull(cloudEvent, nameof(cloudEvent));
@@ -692,22 +797,45 @@ namespace CloudNative.CloudEvents.SystemTextJson
                 cloudEvent.Data = null;
                 return;
             }
-            cloudEvent.Data = JsonSerializer.Deserialize<T>(body.Span, SerializerOptions);
+#if NET7_0_OR_GREATER
+            if (JsonSerializerContext != null)
+                cloudEvent.Data = JsonSerializer.Deserialize(body.Span, typeof(T), JsonSerializerContext);
+            else
+#endif
+                cloudEvent.Data = JsonSerializer.Deserialize<T>(body.Span, SerializerOptions);
         }
 
         /// <inheritdoc />
+#if NET7_0_OR_GREATER
+        [UnconditionalSuppressMessage("Trimming", "IL2026:Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code", Justification = "Constructor already annotated.")]
+        [UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "Constructor already annotated.")]
+#endif
         protected override void EncodeStructuredModeData(CloudEvent cloudEvent, Utf8JsonWriter writer)
         {
-            T data = (T)cloudEvent.Data;
+            var data = (T?)cloudEvent.Data;
             writer.WritePropertyName(DataPropertyName);
-            JsonSerializer.Serialize(writer, data, SerializerOptions);
+#if NET7_0_OR_GREATER
+            if (JsonSerializerContext != null)
+                JsonSerializer.Serialize(writer, data, data!.GetType(), JsonSerializerContext);
+            else
+#endif
+                JsonSerializer.Serialize(writer, data, SerializerOptions);
         }
 
         /// <inheritdoc />
-        protected override void DecodeStructuredModeDataProperty(JsonElement dataElement, CloudEvent cloudEvent) =>
+#if NET7_0_OR_GREATER
-            // Note: this is an inefficient way of doing this.
+        [UnconditionalSuppressMessage("Trimming", "IL2026:Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code", Justification = "Constructor already annotated.")]
-            // See https://github.com/dotnet/runtime/issues/31274 - when that's implemented, we can use the new method here.
+        [UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "Constructor already annotated.")]
-            cloudEvent.Data = JsonSerializer.Deserialize<T>(dataElement.GetRawText(), SerializerOptions);
+#endif
+        protected override void DecodeStructuredModeDataProperty(JsonElement dataElement, CloudEvent cloudEvent)
+        {
+#if NET7_0_OR_GREATER
+            if (JsonSerializerContext != null)
+                cloudEvent.Data = JsonSerializer.Deserialize(dataElement, typeof(T), JsonSerializerContext);
+            else
+#endif
+                cloudEvent.Data = JsonSerializer.Deserialize<T>(dataElement.GetRawText(), SerializerOptions);
+        }
 
         // TODO: Consider decoding the base64 data as a byte array, then using DecodeBinaryModeData.
         /// <inheritdoc />

src/CloudNative.CloudEvents/CloudEventFormatterAttribute.cs

@@ -4,6 +4,7 @@
 
 using CloudNative.CloudEvents.Core;
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 
 namespace CloudNative.CloudEvents
@@ -21,6 +22,9 @@ namespace CloudNative.CloudEvents
         /// <summary>
         /// The type to use for CloudEvent formatting. Must not be null.
         /// </summary>
+#if NET7_0_OR_GREATER
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)]
+#endif
         public Type FormatterType { get; }
 
         /// <summary>
@@ -56,7 +60,7 @@ namespace CloudNative.CloudEvents
                 throw new ArgumentException($"The {nameof(CloudEventFormatterAttribute)} on type {targetType} has no converter type specified.", nameof(targetType));
             }
 
-            object instance;
+            object? instance;
             try
             {
                 instance = Activator.CreateInstance(formatterType);
@@ -73,6 +77,6 @@ namespace CloudNative.CloudEvents
             }
 
             return formatter;
-    }
+        }
     }
 }

src/CloudNative.CloudEvents/CloudNative.CloudEvents.csproj

@@ -1,9 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0;net8.0</TargetFrameworks>
     <Description>CNCF CloudEvents SDK</Description>
-    <LangVersion>latest</LangVersion>
     <Nullable>enable</Nullable>
     <PackageTags>cloudnative;cloudevents;events</PackageTags>
   </PropertyGroup>

src/CloudNative.CloudEvents/Core/BinaryDataUtilities.cs

@@ -32,7 +32,7 @@ namespace CloudNative.CloudEvents.Core
             // It's safe to use memory.GetBuffer() and memory.Position here, as this is a stream
             // we've created using the parameterless constructor.
             var buffer = memory.GetBuffer();
-            return new ReadOnlyMemory<byte>(buffer, 0, (int) memory.Position);
+            return new ReadOnlyMemory<byte>(buffer, 0, (int)memory.Position);
         }
 
         /// <summary>
@@ -65,7 +65,7 @@ namespace CloudNative.CloudEvents.Core
         public static MemoryStream AsStream(ReadOnlyMemory<byte> memory)
         {
             var segment = GetArraySegment(memory);
-            return new MemoryStream(segment.Array, segment.Offset, segment.Count, false);
+            return new MemoryStream(segment.Array!, segment.Offset, segment.Count, false);
         }
 
         /// <summary>
@@ -79,7 +79,7 @@ namespace CloudNative.CloudEvents.Core
 
             // TODO: If we introduce an additional netstandard2.1 target, we can use encoding.GetString(memory.Span)
             var segment = GetArraySegment(memory);
-            return encoding.GetString(segment.Array, segment.Offset, segment.Count);
+            return encoding.GetString(segment.Array!, segment.Offset, segment.Count);
         }
 
         /// <summary>
@@ -92,7 +92,7 @@ namespace CloudNative.CloudEvents.Core
         {
             Validation.CheckNotNull(destination, nameof(destination));
             var segment = GetArraySegment(source);
-            await destination.WriteAsync(segment.Array, segment.Offset, segment.Count).ConfigureAwait(false);
+            await destination.WriteAsync(segment.Array!, segment.Offset, segment.Count).ConfigureAwait(false);
         }
 
         /// <summary>
@@ -108,7 +108,7 @@ namespace CloudNative.CloudEvents.Core
             var segment = GetArraySegment(memory);
             // We probably don't actually need to check the offset: if the count is the same as the length,
             // I can't see how the offset can be non-zero. But it doesn't *hurt* as a check.
-            return segment.Offset == 0 && segment.Count == segment.Array.Length
+            return segment.Array is not null && segment.Offset == 0 && segment.Count == segment.Array.Length
                 ? segment.Array
                 : memory.ToArray();
         }

src/CloudNative.CloudEvents/Core/MimeUtilities.cs

@@ -3,6 +3,7 @@
 // See LICENSE file in the project root for full license information.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Net.Http.Headers;
 using System.Net.Mime;
 using System.Text;
@@ -57,7 +58,7 @@ namespace CloudNative.CloudEvents.Core
             var header = new MediaTypeHeaderValue(contentType.MediaType);
             foreach (string parameterName in contentType.Parameters.Keys)
             {
-                header.Parameters.Add(new NameValueHeaderValue(parameterName, contentType.Parameters[parameterName].ToString()));
+                header.Parameters.Add(new NameValueHeaderValue(parameterName, contentType.Parameters[parameterName]!.ToString()));
             }
             return header;
         }
@@ -76,7 +77,7 @@ namespace CloudNative.CloudEvents.Core
         /// </summary>
         /// <param name="contentType">The content type to check. May be null, in which case the result is false.</param>
         /// <returns>true if the given content type denotes a (non-batch) CloudEvent; false otherwise</returns>
-        public static bool IsCloudEventsContentType(string? contentType) =>
+        public static bool IsCloudEventsContentType([NotNullWhen(true)] string? contentType) =>
             contentType is string &&
             contentType.StartsWith(MediaType, StringComparison.InvariantCultureIgnoreCase) &&
             !contentType.StartsWith(BatchMediaType, StringComparison.InvariantCultureIgnoreCase);
@@ -86,7 +87,7 @@ namespace CloudNative.CloudEvents.Core
         /// </summary>
         /// <param name="contentType">The content type to check. May be null, in which case the result is false.</param>
         /// <returns>true if the given content type represents a CloudEvent batch; false otherwise</returns>
-        public static bool IsCloudEventsBatchContentType(string? contentType) =>
+        public static bool IsCloudEventsBatchContentType([NotNullWhen(true)] string? contentType) =>
             contentType is string && contentType.StartsWith(BatchMediaType, StringComparison.InvariantCultureIgnoreCase);
     }
 }

src/CloudNative.CloudEvents/Http/HttpClientExtensions.cs

@@ -5,6 +5,7 @@
 using CloudNative.CloudEvents.Core;
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Net.Http;
 using System.Net.Http.Headers;
@@ -61,6 +62,7 @@ namespace CloudNative.CloudEvents.Http
             return HasCloudEventsBatchContentType(httpRequestMessage.Content);
         }
 
+        
         /// <summary>
         /// Indicates whether this <see cref="HttpResponseMessage"/> holds a batch of CloudEvents.
         /// </summary>
@@ -83,7 +85,7 @@ namespace CloudNative.CloudEvents.Http
             this HttpResponseMessage httpResponseMessage,
             CloudEventFormatter formatter,
             params CloudEventAttribute[]? extensionAttributes) =>
-            ToCloudEventAsync(httpResponseMessage, formatter, (IEnumerable<CloudEventAttribute>?) extensionAttributes);
+            ToCloudEventAsync(httpResponseMessage, formatter, (IEnumerable<CloudEventAttribute>?)extensionAttributes);
 
         /// <summary>
         /// Converts this HTTP response message into a CloudEvent object
@@ -112,7 +114,7 @@ namespace CloudNative.CloudEvents.Http
             this HttpRequestMessage httpRequestMessage,
             CloudEventFormatter formatter,
             params CloudEventAttribute[]? extensionAttributes) =>
-            ToCloudEventAsync(httpRequestMessage, formatter, (IEnumerable<CloudEventAttribute>?) extensionAttributes);
+            ToCloudEventAsync(httpRequestMessage, formatter, (IEnumerable<CloudEventAttribute>?)extensionAttributes);
 
         /// <summary>
         /// Converts this HTTP request message into a CloudEvent object.
@@ -130,7 +132,7 @@ namespace CloudNative.CloudEvents.Http
             return ToCloudEventInternalAsync(httpRequestMessage.Headers, httpRequestMessage.Content, formatter, extensionAttributes, nameof(httpRequestMessage));
         }
 
-        private static async Task<CloudEvent> ToCloudEventInternalAsync(HttpHeaders headers, HttpContent content,
+        private static async Task<CloudEvent> ToCloudEventInternalAsync(HttpHeaders headers, HttpContent? content,
             CloudEventFormatter formatter, IEnumerable<CloudEventAttribute>? extensionAttributes, string paramName)
         {
             Validation.CheckNotNull(formatter, nameof(formatter));
@@ -142,7 +144,7 @@ namespace CloudNative.CloudEvents.Http
             }
             else
             {
-                string? versionId = MaybeGetVersionId(headers) ?? MaybeGetVersionId(content.Headers);
+                string? versionId = MaybeGetVersionId(headers) ?? MaybeGetVersionId(content?.Headers);
                 if (versionId is null)
                 {
                     throw new ArgumentException($"Request does not represent a CloudEvent. It has neither a {HttpUtilities.SpecVersionHttpHeader} header, nor a suitable content type.", nameof(paramName));
@@ -151,7 +153,7 @@ namespace CloudNative.CloudEvents.Http
                     ?? throw new ArgumentException($"Unknown CloudEvents spec version '{versionId}'", paramName);
 
                 var cloudEvent = new CloudEvent(version, extensionAttributes);
-                foreach (var header in headers.Concat(content.Headers))
+                foreach (var header in headers.Concat(content!.Headers))
                 {
                     string? attributeName = HttpUtilities.GetAttributeNameFromHeaderName(header.Key);
                     if (attributeName is null || attributeName == CloudEventsSpecVersion.SpecVersionAttribute.Name)
@@ -231,7 +233,7 @@ namespace CloudNative.CloudEvents.Http
             return ToCloudEventBatchInternalAsync(httpRequestMessage.Content, formatter, extensionAttributes, nameof(httpRequestMessage));
         }
 
-        private static async Task<IReadOnlyList<CloudEvent>> ToCloudEventBatchInternalAsync(HttpContent content,
+        private static async Task<IReadOnlyList<CloudEvent>> ToCloudEventBatchInternalAsync(HttpContent? content,
             CloudEventFormatter formatter, IEnumerable<CloudEventAttribute>? extensionAttributes, string paramName)
         {
             Validation.CheckNotNull(formatter, nameof(formatter));
@@ -332,15 +334,15 @@ namespace CloudNative.CloudEvents.Http
 
         private static ByteArrayContent ToByteArrayContent(ReadOnlyMemory<byte> content) =>
             MemoryMarshal.TryGetArray(content, out var segment)
-            ? new ByteArrayContent(segment.Array, segment.Offset, segment.Count)
+            ? new ByteArrayContent(segment.Array!, segment.Offset, segment.Count)
             // TODO: Just throw?
             : new ByteArrayContent(content.ToArray());
 
         // TODO: This would include "application/cloudeventsarerubbish" for example...
-        private static bool HasCloudEventsContentType(HttpContent content) =>
+        private static bool HasCloudEventsContentType([NotNullWhen(true)] HttpContent? content) =>
             MimeUtilities.IsCloudEventsContentType(content?.Headers?.ContentType?.MediaType);
 
-        private static bool HasCloudEventsBatchContentType(HttpContent content) =>
+        private static bool HasCloudEventsBatchContentType([NotNullWhen(true)] HttpContent? content) =>
             MimeUtilities.IsCloudEventsBatchContentType(content?.Headers?.ContentType?.MediaType);
 
         private static string? MaybeGetVersionId(HttpHeaders? headers) =>

src/CloudNative.CloudEvents/Http/HttpListenerExtensions.cs

@@ -151,7 +151,7 @@ namespace CloudNative.CloudEvents.Http
         /// <returns>A reference to a validated CloudEvent instance.</returns>
         public static CloudEvent ToCloudEvent(this HttpListenerRequest httpListenerRequest,
             CloudEventFormatter formatter, params CloudEventAttribute[]? extensionAttributes) =>
-            ToCloudEvent(httpListenerRequest, formatter, (IEnumerable<CloudEventAttribute>?) extensionAttributes);
+            ToCloudEvent(httpListenerRequest, formatter, (IEnumerable<CloudEventAttribute>?)extensionAttributes);
 
         /// <summary>
         /// Converts this listener request into a CloudEvent object, with the given extension attributes.
@@ -179,7 +179,7 @@ namespace CloudNative.CloudEvents.Http
             }
             else
             {
-                string versionId = httpListenerRequest.Headers[HttpUtilities.SpecVersionHttpHeader];
+                string? versionId = httpListenerRequest.Headers[HttpUtilities.SpecVersionHttpHeader];
                 if (versionId is null)
                 {
                     throw new ArgumentException($"Request does not represent a CloudEvent. It has neither a {HttpUtilities.SpecVersionHttpHeader} header, nor a suitable content type.", nameof(httpListenerRequest));
@@ -191,12 +191,12 @@ namespace CloudNative.CloudEvents.Http
                 var headers = httpListenerRequest.Headers;
                 foreach (var key in headers.AllKeys)
                 {
-                    string? attributeName = HttpUtilities.GetAttributeNameFromHeaderName(key);
+                    string? attributeName = HttpUtilities.GetAttributeNameFromHeaderName(key!);
                     if (attributeName is null || attributeName == CloudEventsSpecVersion.SpecVersionAttribute.Name)
                     {
                         continue;
                     }
-                    string attributeValue = HttpUtilities.DecodeHeaderValue(headers[key]);
+                    string attributeValue = HttpUtilities.DecodeHeaderValue(headers[key]!);
                     cloudEvent.SetAttributeFromString(attributeName, attributeValue);
                 }
 
@@ -223,7 +223,7 @@ namespace CloudNative.CloudEvents.Http
             this HttpListenerRequest httpListenerRequest,
             CloudEventFormatter formatter,
             params CloudEventAttribute[]? extensionAttributes) =>
-            ToCloudEventBatchAsync(httpListenerRequest, formatter, (IEnumerable<CloudEventAttribute>?)extensionAttributes);
+            ToCloudEventBatchAsync(httpListenerRequest, formatter, (IEnumerable<CloudEventAttribute>?) extensionAttributes);
 
         /// <summary>
         /// Converts this HTTP request message into a CloudEvent batch.
@@ -264,6 +264,7 @@ namespace CloudNative.CloudEvents.Http
             IEnumerable<CloudEventAttribute>? extensionAttributes) =>
             ToCloudEventBatchInternalAsync(httpListenerRequest, formatter, extensionAttributes, async: false).GetAwaiter().GetResult();
 
+        
         private async static Task<IReadOnlyList<CloudEvent>> ToCloudEventBatchInternalAsync(HttpListenerRequest httpListenerRequest,
             CloudEventFormatter formatter, IEnumerable<CloudEventAttribute>? extensionAttributes, bool async)
         {

src/Directory.Build.props

@@ -27,6 +27,10 @@
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <PackageProjectUrl>https://cloudevents.io</PackageProjectUrl>
     <Copyright>Copyright Cloud Native Foundation</Copyright>
+
+    <IsTrimmable Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net6.0'))">true</IsTrimmable>
+    <IsAotCompatible Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net7.0'))">true</IsAotCompatible>
+    <LangVersion>12.0</LangVersion>
   </PropertyGroup>
   
   <!-- Package the icon specified in the PackageIcon property -->

test/CloudNative.CloudEvents.IntegrationTests/CloudNative.CloudEvents.IntegrationTests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

test/CloudNative.CloudEvents.UnitTests/CloudNative.CloudEvents.UnitTests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 

test/CloudNative.CloudEvents.UnitTests/SystemTextJson/ConformanceTest.cs

@@ -4,6 +4,7 @@
 
 using CloudNative.CloudEvents.UnitTests;
 using CloudNative.CloudEvents.UnitTests.ConformanceTestData;
+using Microsoft.Extensions.ObjectPool;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -21,7 +22,8 @@ public class ConformanceTest
     private static IEnumerable<object[]> SelectTestIds(ConformanceTestType type) =>
         allTests
             .Where(test => test.TestType == type)
-            .Select(test => new object[] { test.Id });
+            .Select(test => new object[][] { [test.Id, true], [test.Id, false] })
+            .SelectMany(x => x);
 
     public static IEnumerable<object[]> ValidEventTestIds => SelectTestIds(ConformanceTestType.ValidSingleEvent);
     public static IEnumerable<object[]> InvalidEventTestIds => SelectTestIds(ConformanceTestType.InvalidSingleEvent);
@@ -29,20 +31,21 @@ public class ConformanceTest
     public static IEnumerable<object[]> InvalidBatchTestIds => SelectTestIds(ConformanceTestType.InvalidBatch);
 
     [Theory, MemberData(nameof(ValidEventTestIds))]
-    public void ValidEvent(string testId)
+    public void ValidEvent(string testId, bool useContext)
     {
         var test = GetTestById(testId);
         CloudEvent expected = SampleEvents.FromId(test.SampleId);
         var extensions = test.SampleExtensionAttributes ? SampleEvents.SampleExtensionAttributes : null;
-        CloudEvent actual = new JsonEventFormatter().ConvertFromJsonElement(test.Event, extensions);
+        CloudEvent actual = (useContext ? new JsonEventFormatter(GeneratedJsonContext.Default) : new JsonEventFormatter())
+            .ConvertFromJsonElement(test.Event, extensions);
         TestHelpers.AssertCloudEventsEqual(expected, actual, TestHelpers.InstantOnlyTimestampComparer);
     }
 
     [Theory, MemberData(nameof(InvalidEventTestIds))]
-    public void InvalidEvent(string testId)
+    public void InvalidEvent(string testId, bool useContext)
     {
         var test = GetTestById(testId);
-        var formatter = new JsonEventFormatter();
+        var formatter = useContext ? new JsonEventFormatter(GeneratedJsonContext.Default) : new JsonEventFormatter();
         var extensions = test.SampleExtensionAttributes ? SampleEvents.SampleExtensionAttributes : null;
         // Hmm... we throw FormatException in some cases, when ArgumentException would be better.
         // Changing that would be "somewhat breaking"... it's unclear how much we should worry.
@@ -50,7 +53,7 @@ public class ConformanceTest
     }
 
     [Theory, MemberData(nameof(ValidBatchTestIds))]
-    public void ValidBatch(string testId)
+    public void ValidBatch(string testId, bool useContext)
     {
         var test = GetTestById(testId);
         IReadOnlyList<CloudEvent> expected = SampleBatches.FromId(test.SampleId);
@@ -58,15 +61,16 @@ public class ConformanceTest
         // We don't have a convenience method for batches, so serialize the array back to JSON.
         var json = test.Batch.ToString();
         var body = Encoding.UTF8.GetBytes(json);
-        IReadOnlyList<CloudEvent> actual = new JsonEventFormatter().DecodeBatchModeMessage(body, contentType: null, extensions);
+        IReadOnlyList<CloudEvent> actual = (useContext ? new JsonEventFormatter(GeneratedJsonContext.Default) : new JsonEventFormatter())
+            .DecodeBatchModeMessage(body, contentType: null, extensions);
         TestHelpers.AssertBatchesEqual(expected, actual, TestHelpers.InstantOnlyTimestampComparer);
     }
 
     [Theory, MemberData(nameof(InvalidBatchTestIds))]
-    public void InvalidBatch(string testId)
+    public void InvalidBatch(string testId, bool useContext)
     {
         var test = GetTestById(testId);
-        var formatter = new JsonEventFormatter();
+        var formatter = useContext ? new JsonEventFormatter(GeneratedJsonContext.Default) : new JsonEventFormatter();
         var extensions = test.SampleExtensionAttributes ? SampleEvents.SampleExtensionAttributes : null;
         // We don't have a convenience method for batches, so serialize the array back to JSON.
         var json = test.Batch.ToString();

test/CloudNative.CloudEvents.UnitTests/SystemTextJson/GeneratedJsonContext.cs

@@ -0,0 +1,12 @@
+// Copyright 2023 Cloud Native Foundation.
+// Licensed under the Apache 2.0 license.
+// See LICENSE file in the project root for full license information.
+
+namespace CloudNative.CloudEvents.SystemTextJson.UnitTests;
+
+[System.Text.Json.Serialization.JsonSerializable(typeof(JsonConformanceTest))]
+[System.Text.Json.Serialization.JsonSerializable(typeof(AttributedModel))]
+[System.Text.Json.Serialization.JsonSerializable(typeof(int))]
+internal partial class GeneratedJsonContext : System.Text.Json.Serialization.JsonSerializerContext
+{
+}

test/Directory.Build.props

@@ -14,5 +14,6 @@
     
     <!-- Never pack any test projects -->
     <IsPackable>False</IsPackable>
+    <LangVersion>12.0</LangVersion>
   </PropertyGroup>
 </Project>