Adding STJ Polymorphism to Result Types

src/Http/Http.Extensions/src/RequestDelegateFactory.cs

@@ -1055,7 +1055,7 @@ private static Expression AddResponseWritingToMethodCall(Expression methodCall,
                 {
                     var jsonTypeInfo = factoryContext.JsonSerializerOptions.GetReadOnlyTypeInfo(typeArg);
 
-                    if (jsonTypeInfo.IsPolymorphicSafe() == true)
+                    if (jsonTypeInfo.HasKnownPolymorphism())
                     {
                         return Expression.Call(
                             ExecuteTaskOfTFastMethod.MakeGenericMethod(typeArg),
@@ -1096,7 +1096,7 @@ private static Expression AddResponseWritingToMethodCall(Expression methodCall,
                 {
                     var jsonTypeInfo = factoryContext.JsonSerializerOptions.GetReadOnlyTypeInfo(typeArg);
 
-                    if (jsonTypeInfo.IsPolymorphicSafe() == true)
+                    if (jsonTypeInfo.HasKnownPolymorphism())
                     {
                         return Expression.Call(
                             ExecuteValueTaskOfTFastMethod.MakeGenericMethod(typeArg),
@@ -1140,7 +1140,7 @@ private static Expression AddResponseWritingToMethodCall(Expression methodCall,
         {
             var jsonTypeInfo = factoryContext.JsonSerializerOptions.GetReadOnlyTypeInfo(returnType);
 
-            if (jsonTypeInfo.IsPolymorphicSafe() == true)
+            if (jsonTypeInfo.HasKnownPolymorphism())
             {
                 return Expression.Call(
                     JsonResultWriteResponseOfTFastAsyncMethod.MakeGenericMethod(returnType),

src/Http/Http.Results/src/HttpResultsHelper.cs

@@ -1,12 +1,15 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Diagnostics.CodeAnalysis;
 using System.Text;
 using System.Text.Json;
+using System.Text.Json.Serialization.Metadata;
+using Microsoft.AspNetCore.Http.Json;
 using Microsoft.AspNetCore.Internal;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
 using Microsoft.Net.Http.Headers;
 
 namespace Microsoft.AspNetCore.Http;
@@ -16,13 +19,10 @@ internal static partial class HttpResultsHelper
     internal const string DefaultContentType = "text/plain; charset=utf-8";
     private static readonly Encoding DefaultEncoding = Encoding.UTF8;
 
-    // Remove once https://github.com/dotnet/aspnetcore/pull/46008 is done.
-    [UnconditionalSuppressMessage("Trimming", "IL2026:Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code", Justification = "<Pending>")]
-    [UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "<Pending>")]
-    public static Task WriteResultAsJsonAsync<T>(
+    public static Task WriteResultAsJsonAsync<TValue>(
         HttpContext httpContext,
         ILogger logger,
-        T? value,
+        TValue? value,
         string? contentType = null,
         JsonSerializerOptions? jsonSerializerOptions = null)
     {
@@ -31,32 +31,30 @@ public static Task WriteResultAsJsonAsync<T>(
             return Task.CompletedTask;
         }
 
-        var declaredType = typeof(T);
-        if (declaredType.IsValueType)
-        {
-            Log.WritingResultAsJson(logger, declaredType.Name);
+        jsonSerializerOptions ??= ResolveJsonOptions(httpContext).SerializerOptions;
+        var jsonTypeInfo = (JsonTypeInfo<TValue>)jsonSerializerOptions.GetTypeInfo(typeof(TValue));
 
-            // In this case the polymorphism is not
-            // relevant and we don't need to box.
+        Type? runtimeType;
+        if (jsonTypeInfo.IsValid(runtimeType = value.GetType()))
+        {
+            Log.WritingResultAsJson(logger, jsonTypeInfo.Type.Name);
             return httpContext.Response.WriteAsJsonAsync(
-                        value,
-                        options: jsonSerializerOptions,
-                        contentType: contentType);
+                value,
+                jsonTypeInfo,
+                contentType: contentType);
         }
 
-        var runtimeType = value.GetType();
-
         Log.WritingResultAsJson(logger, runtimeType.Name);
-
-        // Call WriteAsJsonAsync() with the runtime type to serialize the runtime type rather than the declared type
+        // Since we don't know the type's polymorphic characteristics
+        // our best option is use the runtime type, so,
+        // call WriteAsJsonAsync() with the runtime type to serialize the runtime type rather than the declared type
         // and avoid source generators issues.
         // https://github.com/dotnet/aspnetcore/issues/43894
         // https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json-polymorphism
         return httpContext.Response.WriteAsJsonAsync(
-            value,
-            runtimeType,
-            options: jsonSerializerOptions,
-            contentType: contentType);
+           value,
+           jsonSerializerOptions.GetTypeInfo(runtimeType),
+           contentType: contentType);
     }
 
     public static Task WriteResultAsContentAsync(
@@ -146,6 +144,12 @@ public static void ApplyProblemDetailsDefaultsIfNeeded(object? value, int? statu
         }
     }
 
+    private static JsonOptions ResolveJsonOptions(HttpContext httpContext)
+    {
+        // Attempt to resolve options from DI then fallback to default options
+        return httpContext.RequestServices.GetService<IOptions<JsonOptions>>()?.Value ?? new JsonOptions();
+    }
+
     internal static partial class Log
     {
         [LoggerMessage(1, LogLevel.Information,

src/Http/Http.Results/src/JsonHttpResultOfT.cs

@@ -1,7 +1,9 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Text.Json;
+using System.Text.Json.Serialization.Metadata;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
@@ -18,33 +20,33 @@ public sealed partial class JsonHttpResult<TValue> : IResult, IStatusCodeHttpRes
     /// </summary>
     /// <param name="value">The value to format in the entity body.</param>
     /// <param name="jsonSerializerOptions">The serializer settings.</param>
-    internal JsonHttpResult(TValue? value, JsonSerializerOptions? jsonSerializerOptions)
-        : this(value, statusCode: null, contentType: null, jsonSerializerOptions: jsonSerializerOptions)
-    {
-    }
-
-    /// <summary>
-    /// Initializes a new instance of the <see cref="Json"/> class with the values.
-    /// </summary>
-    /// <param name="value">The value to format in the entity body.</param>
     /// <param name="statusCode">The HTTP status code of the response.</param>
-    /// <param name="jsonSerializerOptions">The serializer settings.</param>
-    internal JsonHttpResult(TValue? value, int? statusCode, JsonSerializerOptions? jsonSerializerOptions)
-        : this(value, statusCode: statusCode, contentType: null, jsonSerializerOptions: jsonSerializerOptions)
+    /// <param name="contentType">The value for the <c>Content-Type</c> header</param>
+    [RequiresDynamicCode(JsonHttpResultTrimmerWarning.SerializationRequiresDynamicCodeMessage)]
+    [RequiresUnreferencedCode(JsonHttpResultTrimmerWarning.SerializationUnreferencedCodeMessage)]
+    internal JsonHttpResult(TValue? value, JsonSerializerOptions? jsonSerializerOptions, int? statusCode = null, string? contentType = null)
     {
+        Value = value;
+        ContentType = contentType;
+
+        if (value is ProblemDetails problemDetails)
+        {
+            ProblemDetailsDefaults.Apply(problemDetails, statusCode);
+            statusCode ??= problemDetails.Status;
+        }
+        StatusCode = statusCode;
+
+        if (jsonSerializerOptions is not null && !jsonSerializerOptions.IsReadOnly)
+        {
+            jsonSerializerOptions.TypeInfoResolver ??= new DefaultJsonTypeInfoResolver();
+        }
+
+        JsonSerializerOptions = jsonSerializerOptions;
     }
 
-    /// <summary>
-    /// Initializes a new instance of the <see cref="Json"/> class with the values.
-    /// </summary>
-    /// <param name="value">The value to format in the entity body.</param>
-    /// <param name="statusCode">The HTTP status code of the response.</param>
-    /// <param name="jsonSerializerOptions">The serializer settings.</param>
-    /// <param name="contentType">The value for the <c>Content-Type</c> header</param>
-    internal JsonHttpResult(TValue? value, int? statusCode, string? contentType, JsonSerializerOptions? jsonSerializerOptions)
+    internal JsonHttpResult(TValue? value, int? statusCode = null, string? contentType = null)
     {
         Value = value;
-        JsonSerializerOptions = jsonSerializerOptions;
         ContentType = contentType;
 
         if (value is ProblemDetails problemDetails)
@@ -59,7 +61,12 @@ internal JsonHttpResult(TValue? value, int? statusCode, string? contentType, Jso
     /// <summary>
     /// Gets or sets the serializer settings.
     /// </summary>
-    public JsonSerializerOptions? JsonSerializerOptions { get; internal init; }
+    public JsonSerializerOptions? JsonSerializerOptions { get; }
+
+    /// <summary>
+    /// Gets or sets the serializer settings.
+    /// </summary>
+    internal JsonTypeInfo? JsonTypeInfo { get; init; }
 
     /// <summary>
     /// Gets the object result.
@@ -71,7 +78,7 @@ internal JsonHttpResult(TValue? value, int? statusCode, string? contentType, Jso
     /// <summary>
     /// Gets the value for the <c>Content-Type</c> header.
     /// </summary>
-    public string? ContentType { get; internal set; }
+    public string? ContentType { get; }
 
     /// <summary>
     /// Gets the HTTP status code.
@@ -93,6 +100,30 @@ public Task ExecuteAsync(HttpContext httpContext)
             httpContext.Response.StatusCode = statusCode;
         }
 
+        if (Value is null)
+        {
+            return Task.CompletedTask;
+        }
+
+        if (JsonTypeInfo != null)
+        {
+            HttpResultsHelper.Log.WritingResultAsJson(logger, JsonTypeInfo.Type.Name);
+
+            if (JsonTypeInfo is JsonTypeInfo<TValue> typedJsonTypeInfo)
+            {
+                // We don't need to box here.
+                return httpContext.Response.WriteAsJsonAsync(
+                    Value,
+                    typedJsonTypeInfo,
+                    contentType: ContentType);
+
+            }
+            return httpContext.Response.WriteAsJsonAsync(
+                Value,
+                JsonTypeInfo,
+                contentType: ContentType);
+        }
+
         return HttpResultsHelper.WriteResultAsJsonAsync(
             httpContext,
             logger,

src/Http/Http.Results/src/JsonHttpResultTrimmerWarning.cs

@@ -0,0 +1,11 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Http;
+
+internal class JsonHttpResultTrimmerWarning
+{
+    public const string SerializationUnreferencedCodeMessage = "JSON serialization and deserialization might require types that cannot be statically analyzed. Use the overload that takes a JsonTypeInfo or JsonSerializerContext.";
+    public const string SerializationRequiresDynamicCodeMessage = "JSON serialization and deserialization might require types that cannot be statically analyzed and might need runtime code generation. Use the overload that takes a JsonTypeInfo or JsonSerializerContext.";
+
+}

src/Http/Http.Results/src/Microsoft.AspNetCore.Http.Results.csproj

@@ -19,6 +19,7 @@
     <Compile Include="$(SharedSourceRoot)ProblemDetails\ProblemDetailsDefaults.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)ApiExplorerTypes\*.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)RoutingMetadata\AcceptsMetadata.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)Json\JsonSerializerExtensions.cs" LinkBase="Shared"/>
     <Compile Include="$(SharedSourceRoot)RouteValueDictionaryTrimmerWarning.cs" LinkBase="Shared" />
   </ItemGroup>
 

src/Http/Http.Results/src/PublicAPI.Unshipped.txt

@@ -12,6 +12,10 @@ static Microsoft.AspNetCore.Http.Results.Created(string? uri, object? value) ->
 static Microsoft.AspNetCore.Http.Results.Created(System.Uri? uri, object? value) -> Microsoft.AspNetCore.Http.IResult!
 static Microsoft.AspNetCore.Http.Results.Created<TValue>(string? uri, TValue? value) -> Microsoft.AspNetCore.Http.IResult!
 static Microsoft.AspNetCore.Http.Results.Created<TValue>(System.Uri? uri, TValue? value) -> Microsoft.AspNetCore.Http.IResult!
+static Microsoft.AspNetCore.Http.Results.Json(object? data, System.Text.Json.Serialization.Metadata.JsonTypeInfo! jsonTypeInfo, string? contentType = null, int? statusCode = null) -> Microsoft.AspNetCore.Http.IResult!
+static Microsoft.AspNetCore.Http.Results.Json(object? data, System.Type! type, System.Text.Json.Serialization.JsonSerializerContext! context, string? contentType = null, int? statusCode = null) -> Microsoft.AspNetCore.Http.IResult!
+static Microsoft.AspNetCore.Http.Results.Json<TValue>(TValue? data, System.Text.Json.Serialization.JsonSerializerContext! context, string? contentType = null, int? statusCode = null) -> Microsoft.AspNetCore.Http.IResult!
+static Microsoft.AspNetCore.Http.Results.Json<TValue>(TValue? data, System.Text.Json.Serialization.Metadata.JsonTypeInfo<TValue>! jsonTypeInfo, string? contentType = null, int? statusCode = null) -> Microsoft.AspNetCore.Http.IResult!
 static Microsoft.AspNetCore.Http.TypedResults.Created() -> Microsoft.AspNetCore.Http.HttpResults.Created!
 static Microsoft.AspNetCore.Http.TypedResults.Created(string? uri) -> Microsoft.AspNetCore.Http.HttpResults.Created!
 static Microsoft.AspNetCore.Http.TypedResults.Created(System.Uri? uri) -> Microsoft.AspNetCore.Http.HttpResults.Created!
@@ -22,4 +26,6 @@ static Microsoft.AspNetCore.Http.TypedResults.Created<TValue>(System.Uri? uri, T
 *REMOVED*static Microsoft.AspNetCore.Http.TypedResults.Created(System.Uri! uri) -> Microsoft.AspNetCore.Http.HttpResults.Created!
 *REMOVED*static Microsoft.AspNetCore.Http.TypedResults.Created(string! uri) -> Microsoft.AspNetCore.Http.HttpResults.Created!
 *REMOVED*static Microsoft.AspNetCore.Http.TypedResults.Created<TValue>(System.Uri! uri, TValue? value) -> Microsoft.AspNetCore.Http.HttpResults.Created<TValue>!
-*REMOVED*static Microsoft.AspNetCore.Http.TypedResults.Created<TValue>(string! uri, TValue? value) -> Microsoft.AspNetCore.Http.HttpResults.Created<TValue>!
+*REMOVED*static Microsoft.AspNetCore.Http.TypedResults.Created<TValue>(string! uri, TValue? value) -> Microsoft.AspNetCore.Http.HttpResults.Created<TValue>!
+static Microsoft.AspNetCore.Http.TypedResults.Json<TValue>(TValue? data, System.Text.Json.Serialization.JsonSerializerContext! context, string? contentType = null, int? statusCode = null) -> Microsoft.AspNetCore.Http.HttpResults.JsonHttpResult<TValue>!
+static Microsoft.AspNetCore.Http.TypedResults.Json<TValue>(TValue? data, System.Text.Json.Serialization.Metadata.JsonTypeInfo<TValue>! jsonTypeInfo, string? contentType = null, int? statusCode = null) -> Microsoft.AspNetCore.Http.HttpResults.JsonHttpResult<TValue>!