Allow AcceptsAttribute request type named argument (#17)

Author: jscarle

README.md

@@ -240,6 +240,12 @@ public sealed class CreateTodo
 }
 ```
 
+When you can't use the generic form (for example, the request type is only known at runtime), set the `RequestType` named argument instead:
+
+```csharp
+[Accepts("application/xml", RequestType = typeof(CreateTodoRequest))]
+```
+
 The generator translates these attributes into `.Accepts`, `.Produces`, `.ProducesProblem`, and `.ProducesValidationProblem`
 calls on the endpoint builder.
 

src/GeneratedEndpoints/MinimalApiGenerator.cs

@@ -59,6 +59,7 @@ public sealed class MinimalApiGenerator : IIncrementalGenerator
     private const string SummaryAttributeNamedParameter = "Summary";
     private const string DescriptionAttributeNamedParameter = "Description";
     private const string ResponseTypeAttributeNamedParameter = "ResponseType";
+    private const string RequestTypeAttributeNamedParameter = "RequestType";
 
     private const string RequireAuthorizationAttributeName = "RequireAuthorizationAttribute";
     private const string RequireAuthorizationAttributeFullyQualifiedName = $"{AttributesNamespace}.{RequireAuthorizationAttributeName}";
@@ -281,7 +282,7 @@ internal sealed class {{AcceptsAttributeName}} : global::System.Attribute
                                    /// <summary>
                                    /// Gets the request type accepted by the endpoint.
                                    /// </summary>
-                                   public global::System.Type RequestType { get; }
+                                   public global::System.Type RequestType { get; init; } = default!;
 
                                    /// <summary>
                                    /// Gets the primary content type accepted by the endpoint.
@@ -296,12 +297,10 @@ internal sealed class {{AcceptsAttributeName}} : global::System.Attribute
                                    /// <summary>
                                    /// Initializes a new instance of the <see cref="{{AcceptsAttributeName}}"/> class.
                                    /// </summary>
-                                   /// <param name="requestType">The CLR type of the request body.</param>
                                    /// <param name="contentType">The primary content type accepted by the endpoint.</param>
                                    /// <param name="additionalContentTypes">Additional content types accepted by the endpoint.</param>
-                                   public {{AcceptsAttributeName}}(global::System.Type requestType, string contentType = "application/json", params string[] additionalContentTypes)
+                                   public {{AcceptsAttributeName}}(string contentType = "application/json", params string[] additionalContentTypes)
                                    {
-                                       RequestType = requestType ?? throw new global::System.ArgumentNullException(nameof(requestType));
                                        ContentType = string.IsNullOrWhiteSpace(contentType) ? "application/json" : contentType;
                                        AdditionalContentTypes = additionalContentTypes ?? [];
                                    }
@@ -927,15 +926,14 @@ private static void TryAddAcceptsMetadata(
                 ? GetStringArrayValues(attribute.ConstructorArguments[1])
                 : null;
         }
-        else if (attribute.ConstructorArguments.Length >= 1 &&
-                 attribute.ConstructorArguments[0].Value is ITypeSymbol requestTypeSymbol)
+        else if (GetNamedTypeSymbol(attribute, RequestTypeAttributeNamedParameter) is { } requestTypeSymbol)
         {
             requestType = requestTypeSymbol.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
-            contentType = attribute.ConstructorArguments.Length > 1
-                ? NormalizeRequiredContentType(attribute.ConstructorArguments[1].Value as string, "application/json")
+            contentType = attribute.ConstructorArguments.Length > 0
+                ? NormalizeRequiredContentType(attribute.ConstructorArguments[0].Value as string, "application/json")
                 : "application/json";
-            additionalContentTypes = attribute.ConstructorArguments.Length > 2
-                ? GetStringArrayValues(attribute.ConstructorArguments[2])
+            additionalContentTypes = attribute.ConstructorArguments.Length > 1
+                ? GetStringArrayValues(attribute.ConstructorArguments[1])
                 : null;
         }
         else

tests/GeneratedEndpoints.Tests.Lab/GetUserEndpoint.cs

@@ -14,7 +14,7 @@ internal static class GetUserEndpoint
 {
     [Tags("Featured")]
     [AllowAnonymous]
-    [Accepts(typeof(GetUserRequest), "application/json", "application/xml")]
+    [Accepts("application/json", "application/xml", RequestType = typeof(GetUserRequest))]
     [Accepts<GetUserMetadata>("application/json", "application/xml")]
     [ProducesResponse( StatusCodes.Status200OK, "application/json", ResponseType = typeof(UserProfile))]
     [ProducesResponse<UserProfile>(StatusCodes.Status202Accepted, "application/json")]

tests/GeneratedEndpoints.Tests/GeneratedEndpointsTests.cs

@@ -115,7 +115,7 @@ public async Task MapAllAttributesAndHttpMethods(bool withNamespace)
                                              [Tags("Shared", "ClassLevel")]
                                              [RequireAuthorization("PolicyA", "PolicyB")]
                                              [DisableAntiforgery]
-                                             [Accepts(typeof(ClassLevelRequest), "application/xml", "text/xml")]
+                                             [Accepts("application/xml", "text/xml", RequestType = typeof(ClassLevelRequest))]
                                              [ProducesResponse(201, "application/json", "text/json", ResponseType = typeof(ClassLevelResponse))]
                                              [ProducesProblem(503, "application/problem+json")]
                                              [ProducesValidationProblem(409, "application/problem+json", "text/plain")]
@@ -138,8 +138,8 @@ public static void Configure<TBuilder>(TBuilder builder, IServiceProvider servic
                                                  [AllowAnonymous]
                                                  [Tags("MethodLevel")]
                                                  [RequireAuthorization("MethodPolicy")]
-                                                 [Accepts<GetRequest>("application/custom", "text/custom")]
-                                                   [Microsoft.AspNetCore.Generated.Attributes.ProducesResponse<GetResponse>(200, "application/json", "text/json")]
+                                                [Accepts<GetRequest>("application/custom", "text/custom")]
+                                                  [Microsoft.AspNetCore.Generated.Attributes.ProducesResponse<GetResponse>(200, "application/json", "text/json")]
                                                  [ProducesProblem(400, "application/problem+json", "text/plain")]
                                                  [ProducesValidationProblem(422, "application/problem+json", "text/plain")]
                                                  [ExcludeFromDescription]