Refactor Minimal API support to make the setups consistent

Author: commonsensesoftware

examples/AspNetCore/WebApi/MinimalOpenApiExample/Program.cs

@@ -297,7 +297,7 @@
 
 if ( app.Environment.IsDevelopment() )
 {
-    app.IncludeVersionedEndpoints().MapOpenApi().WithDocumentPerVersion();
+    app.MapOpenApi().WithDocumentPerVersion();
     app.MapScalarApiReference(
         options =>
         {

src/AspNetCore/WebApi/src/Asp.Versioning.OpenApi/Builder/IEndpointConventionBuilderExtensions.cs

@@ -6,13 +6,10 @@ namespace Microsoft.AspNetCore.Builder;
 
 using Asp.Versioning;
 using Asp.Versioning.ApiExplorer;
-using Asp.Versioning.OpenApi;
 using Asp.Versioning.OpenApi.Internal;
 using Microsoft.AspNetCore.Builder;
-using Microsoft.AspNetCore.OpenApi;
-using Microsoft.AspNetCore.Routing;
+using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.DependencyInjection;
-using System.Diagnostics.CodeAnalysis;
 
 /// <summary>
 /// Provides extension methods for <see cref="IEndpointConventionBuilder"/>.
@@ -32,91 +29,27 @@ public static class IEndpointConventionBuilderExtensions
         /// <returns>The original <see cref="IEndpointConventionBuilder">endpoint convention builder</see>.</returns>
         public IEndpointConventionBuilder WithDocumentPerVersion()
         {
-            builder.Finally( new WithoutRecursion().Run );
+            builder.Finally( ApplyApiVersioning );
             return builder;
         }
     }
 
-    // This is a workaround to prevent infinite recursion when applying API versioning conventions to the OpenAPI
-    // endpoint, which occurs because IApiVersionDescriptionProviderFactory.Create calls back into the endpoint's
-    // RequestDelegate to resolve the IApiVersionDescriptionProvider, which causes the conventions to be applied again.
-    private sealed class WithoutRecursion
-    {
-        private bool recursed;
-
-        public void Run( EndpointBuilder builder )
-        {
-            if ( recursed )
-            {
-                return;
-            }
-
-            recursed = true;
-            ApplyApiVersioning( builder );
-            recursed = false;
-        }
-    }
-
     private static void ApplyApiVersioning( EndpointBuilder builder )
     {
         if ( builder.RequestDelegate is { } action )
         {
-#pragma warning disable CA2000 // Dispose objects before losing scope
-            var requestServices = NewRequestServices( builder.ApplicationServices );
-#pragma warning restore CA2000 // Dispose objects before losing scope
-
-            builder.RequestDelegate = context =>
-            {
-                context.RequestServices = requestServices;
-                return action( context );
-            };
+            builder.RequestDelegate = context => InterceptRequestServices( context, action );
         }
     }
 
-    [UnconditionalSuppressMessage( "ILLink", "IL3050" )]
-    private static KeyedServiceContainer NewRequestServices( IServiceProvider services )
+    private static Task InterceptRequestServices( HttpContext context, RequestDelegate action )
     {
-        var configure = services.GetRequiredKeyedService<Action<ApiVersionDescription, OpenApiOptions>>( typeof( ApiVersion ) );
-        var factory = services.GetRequiredService<IApiVersionDescriptionProviderFactory>();
-        var sources = services.GetRequiredService<ConfigureOpenApiOptions>().DataSources;
-        var keyedServices = new KeyedServiceContainer( services );
-        var names = new List<string>();
-        IApiVersionDescriptionProvider provider;
-
-        if ( sources.Count == 0 )
+        if ( context.RequestServices is not KeyedServiceContainer requestServices )
         {
-            provider = factory.Create();
-        }
-        else
-        {
-            using var source = new CompositeEndpointDataSource( sources );
-            provider = factory.Create( source );
-        }
-
-        foreach ( var description in provider.ApiVersionDescriptions )
-        {
-            names.Add( description.GroupName );
-            keyedServices.Add( Type.OpenApiSchemaService, description.GroupName, Class.OpenApiSchemaService.New );
-            keyedServices.Add( Type.OpenApiDocumentService, description.GroupName, Class.OpenApiDocumentService.New );
-            keyedServices.Add(
-                typeof( IOpenApiDocumentProvider ),
-                description.GroupName,
-                ( sp, k ) => sp.GetRequiredKeyedService( Type.OpenApiDocumentService, k ) );
-        }
-
-        if ( names.Count > 0 )
-        {
-            var array = Array.CreateInstance( Type.NamedService, names.Count );
-
-            for ( var i = 0; i < names.Count; i++ )
-            {
-                array.SetValue( Class.NamedService.New( names[i] ), i );
-            }
-
-            keyedServices.Add( Type.IDocumentProvider, Class.OpenApiDocumentProvider.New );
-            keyedServices.Add( Type.IEnumerableOfNamedService, array );
+            requestServices = context.RequestServices.GetRequiredService<KeyedServiceContainer>();
         }
 
-        return keyedServices;
+        context.RequestServices = requestServices;
+        return action( context );
     }
 }

src/AspNetCore/WebApi/src/Asp.Versioning.OpenApi/Builder/IEndpointRouteBuilderExtensions.cs

@@ -7,6 +7,8 @@ namespace Microsoft.Extensions.DependencyInjection;
 using Asp.Versioning;
 using Asp.Versioning.ApiExplorer;
 using Asp.Versioning.OpenApi;
+using Asp.Versioning.OpenApi.Internal;
+using Asp.Versioning.OpenApi.Transformers;
 using Microsoft.AspNetCore.Http.Json;
 using Microsoft.AspNetCore.OpenApi;
 using Microsoft.Extensions.DependencyInjection.Extensions;
@@ -96,8 +98,10 @@ private static void AddOpenApiServices( IApiVersioningBuilder builder )
 
         var services = builder.Services;
 
+        services.AddTransient( NewRequestServices );
+        services.Add( Singleton( Type.IDocumentProvider, ResolveDocumentProvider ) );
         services.AddOptions<OpenApiDocumentDescriptionOptions>();
-        services.Add( Singleton<ConfigureOpenApiOptions, ConfigureOpenApiOptions>() );
+        services.Add( Transient<ConfigureOpenApiOptions, ConfigureOpenApiOptions>() );
         services.TryAddEnumerable( Singleton<IConfigureOptions<OpenApiOptions>, ConfigureOpenApiOptions>( static sp => sp.GetRequiredService<ConfigureOpenApiOptions>() ) );
 
         if ( GetJsonConfiguration() is { } descriptor )
@@ -118,4 +122,42 @@ private static void AddOpenApiServices( IApiVersioningBuilder builder )
 #pragma warning disable IDE0060
 
     private static Action<ApiVersionDescription, OpenApiOptions> NoOptions( IServiceProvider provider, object key ) => static ( _, _ ) => { };
+
+    private static object ResolveDocumentProvider( IServiceProvider provider ) =>
+        provider.GetRequiredService<KeyedServiceContainer>().GetRequiredService( Type.IDocumentProvider );
+
+    [UnconditionalSuppressMessage( "ILLink", "IL3050" )]
+    private static KeyedServiceContainer NewRequestServices( IServiceProvider services )
+    {
+        var configure = services.GetRequiredKeyedService<Action<ApiVersionDescription, OpenApiOptions>>( typeof( ApiVersion ) );
+        var provider = services.GetRequiredService<IApiVersionDescriptionProvider>();
+        var keyedServices = new KeyedServiceContainer( services );
+        var names = new List<string>();
+
+        foreach ( var description in provider.ApiVersionDescriptions )
+        {
+            names.Add( description.GroupName );
+            keyedServices.Add( Type.OpenApiSchemaService, description.GroupName, Class.OpenApiSchemaService.New );
+            keyedServices.Add( Type.OpenApiDocumentService, description.GroupName, Class.OpenApiDocumentService.New );
+            keyedServices.Add(
+                typeof( IOpenApiDocumentProvider ),
+                description.GroupName,
+                ( sp, k ) => sp.GetRequiredKeyedService( Type.OpenApiDocumentService, k ) );
+        }
+
+        if ( names.Count > 0 )
+        {
+            var array = Array.CreateInstance( Type.NamedService, names.Count );
+
+            for ( var i = 0; i < names.Count; i++ )
+            {
+                array.SetValue( Class.NamedService.New( names[i] ), i );
+            }
+
+            keyedServices.Add( Type.IDocumentProvider, Class.OpenApiDocumentProvider.New );
+            keyedServices.Add( Type.IEnumerableOfNamedService, array );
+        }
+
+        return keyedServices;
+    }
 }