Make MVC's JsonOptions inherit settings from Http's JsonOptions

Author: JamesNK

src/Mvc/Mvc.Core/src/DependencyInjection/MvcCoreServiceCollectionExtensions.cs

@@ -141,6 +141,8 @@ internal static void AddMvcCoreServices(IServiceCollection services)
             //
             // Options
             //
+            services.TryAddEnumerable(
+                ServiceDescriptor.Transient<IOptionsFactory<JsonOptions>, JsonOptionsFactory>());
             services.TryAddEnumerable(
                 ServiceDescriptor.Transient<IConfigureOptions<MvcOptions>, MvcCoreMvcOptionsSetup>());
             services.TryAddEnumerable(

src/Mvc/Mvc.Core/src/JsonOptions.cs

@@ -12,20 +12,32 @@ public class JsonOptions
         /// Gets the <see cref="System.Text.Json.JsonSerializerOptions"/> used by <see cref="SystemTextJsonInputFormatter"/> and
         /// <see cref="SystemTextJsonOutputFormatter"/>.
         /// </summary>
-        public JsonSerializerOptions JsonSerializerOptions { get; } = new JsonSerializerOptions
+        public JsonSerializerOptions JsonSerializerOptions { get; }
+
+        public JsonOptions()
         {
-            // Limit the object graph we'll consume to a fixed depth. This prevents stackoverflow exceptions
-            // from deserialization errors that might occur from deeply nested objects.
-            // This value is the same for model binding and Json.Net's serialization.
-            MaxDepth = MvcOptions.DefaultMaxModelBindingRecursionDepth,
+            JsonSerializerOptions = new JsonSerializerOptions
+            {
+                // Limit the object graph we'll consume to a fixed depth. This prevents stackoverflow exceptions
+                // from deserialization errors that might occur from deeply nested objects.
+                // This value is the same for model binding and Json.Net's serialization.
+                MaxDepth = MvcOptions.DefaultMaxModelBindingRecursionDepth,
+
+                // We're using case-insensitive because there's a TON of code that there that does uses JSON.NET's default
+                // settings (preserve case) - including the WebAPIClient. This worked when we were using JSON.NET + camel casing
+                // because JSON.NET is case-insensitive by default.
+                PropertyNameCaseInsensitive = true,
 
-            // We're using case-insensitive because there's a TON of code that there that does uses JSON.NET's default
-            // settings (preserve case) - including the WebAPIClient. This worked when we were using JSON.NET + camel casing
-            // because JSON.NET is case-insensitive by default.
-            PropertyNameCaseInsensitive = true,
+                // Use camel casing for properties
+                PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+            };
+        }
 
-            // Use camel casing for properties
-            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
-        };
+        // Initialize JsonOptions with already configured serializer options.
+        // Note that these options will be publically accessible.
+        internal JsonOptions(JsonSerializerOptions serializerOptions)
+        {
+            JsonSerializerOptions = serializerOptions;
+        }
     }
 }

src/Mvc/Mvc.Core/src/JsonOptionsFactory.cs

@@ -0,0 +1,34 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Text.Json;
+using Microsoft.Extensions.Options;
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    /// <summary>
+    /// This factory copies settings from Microsoft.AspNetCore.Http.Json.JsonOptions,
+    /// and they are used as the base for any additional MVC serialization configuration.
+    /// Changes applies to Microsoft.AspNetCore.Mvc.JsonOptions are isolated to MVC.
+    /// </summary>
+    internal class JsonOptionsFactory : OptionsFactory<JsonOptions>
+    {
+        private JsonSerializerOptions _serializerOptions;
+
+        public JsonOptionsFactory(
+            IOptions<Http.Json.JsonOptions> options,
+            IEnumerable<IConfigureOptions<JsonOptions>> setups,
+            IEnumerable<IPostConfigureOptions<JsonOptions>> postConfigures,
+            IEnumerable<IValidateOptions<JsonOptions>> validations) : base(setups, postConfigures, validations)
+        {
+            _serializerOptions = options.Value.SerializerOptions;
+        }
+
+        protected override JsonOptions CreateInstance(string name)
+        {
+            // Copy values from Microsoft.AspNetCore.Http.Json.JsonOptions serializer options.
+            return new JsonOptions(new JsonSerializerOptions(_serializerOptions));
+        }
+    }
+}