.NET 10 preparation

Cherry-pick changes from #231 ahead of updating to .NET 10 in November.

Author: martincostello

src/TodoApp/ApiEndpoints.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Martin Costello, 2024. All rights reserved.
 // Licensed under the Apache 2.0 license. See the LICENSE file in the project root for full license information.
 
+using System.Text.Json.Serialization;
 using Microsoft.AspNetCore.Http.HttpResults;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
@@ -33,6 +34,15 @@ public static IServiceCollection AddTodoApi(this IServiceCollection services)
         services.AddScoped<ITodoRepository, TodoRepository>();
         services.AddScoped<ITodoService, TodoService>();
 
+        // Use the same JSON serializer options for OpenAPI as for the API itself
+        services.ConfigureHttpJsonOptions(options =>
+        {
+            options.SerializerOptions.DefaultIgnoreCondition = TodoJsonSerializerContext.Default.Options.DefaultIgnoreCondition;
+            options.SerializerOptions.NumberHandling = TodoJsonSerializerContext.Default.Options.NumberHandling;
+            options.SerializerOptions.PropertyNamingPolicy = TodoJsonSerializerContext.Default.Options.PropertyNamingPolicy;
+            options.SerializerOptions.WriteIndented = TodoJsonSerializerContext.Default.Options.WriteIndented;
+        });
+
         // Configure an EFCore data context to store the Todos backed by SQLite
         services.AddDbContext<TodoContext>((serviceProvider, options) =>
         {

src/TodoApp/OpenApi/ExamplesProcessor.cs

@@ -34,7 +34,7 @@ protected void Process(OpenApiOperation operation, ApiDescription description)
             TryAddRequestExamples(body, description, examples);
         }
 
-        TryAddResponseExamples(operation.Responses, description, examples);
+        TryAddResponseExamples(operation.Responses ?? [], description, examples);
     }
 
     protected void Process(OpenApiSchema schema, Type type)
@@ -81,8 +81,7 @@ private static void TryAddParameterExamples(
                 if (metadata?.GenerateExample(Context) is { } value)
                 {
                     // Find the parameter that corresponds to the argument and set its example
-                    var parameter = parameters.FirstOrDefault((p) => p.Name == argument.Name);
-                    if (parameter is not null)
+                    if (parameters.FirstOrDefault((p) => p.Name == argument.Name) is OpenApiParameter parameter)
                     {
                         parameter.Example ??= value;
                     }

src/TodoApp/OpenApi/Swashbuckle/AddDocumentTagsFilter.cs

@@ -13,6 +13,7 @@ public class AddDocumentTagsFilter : IDocumentFilter
 {
     public void Apply(OpenApiDocument swaggerDoc, DocumentFilterContext context)
     {
+        swaggerDoc.Tags ??= [];
         swaggerDoc.Tags.Add(new() { Name = "TodoApp" });
     }
 }

src/TodoApp/TodoJsonSerializerContext.cs

@@ -20,6 +20,7 @@ namespace TodoApp;
 [JsonSerializable(typeof(TodoListViewModel))]
 [JsonSourceGenerationOptions(
     DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
+    NumberHandling = JsonNumberHandling.Strict,
     PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase,
     WriteIndented = true)]
 public sealed partial class TodoJsonSerializerContext : JsonSerializerContext;