Use all content-types

Author: halter73

src/Mvc/Mvc.ApiExplorer/src/ApiResponseTypeProvider.cs

@@ -140,7 +140,7 @@ internal static List<ApiResponseType> ReadResponseMetadata(
                         {
                             // ProducesResponseTypeAttribute's constructor defaults to setting "Type" to void when no value is specified.
                             // In this event, use the action's return type for 200 or 201 status codes. This lets you decorate an action with a
-                            // [ProducesResponseType(201)] instead of [ProducesResponseType(201, typeof(Person)] when typeof(Person) can be inferred
+                            // [ProducesResponseType(201)] instead of [ProducesResponseType(typeof(Person), 201] when typeof(Person) can be inferred
                             // from the return type.
                             apiResponseType.Type = type;
                         }
@@ -159,6 +159,7 @@ internal static List<ApiResponseType> ReadResponseMetadata(
 
                     if (apiResponseType.Type != null)
                     {
+                        AddApiResponseFormats(apiResponseType.ApiResponseFormats, contentTypes);
                         results[apiResponseType.StatusCode] = apiResponseType;
                     }
                 }
@@ -167,6 +168,17 @@ internal static List<ApiResponseType> ReadResponseMetadata(
             return results.Values.ToList();
         }
 
+        internal static void AddApiResponseFormats(IList<ApiResponseFormat> apiResponseFormats, IReadOnlyList<string> contentTypes)
+        {
+            foreach (var contentType in contentTypes)
+            {
+                apiResponseFormats.Add(new ApiResponseFormat
+                {
+                    MediaType = contentType,
+                });
+            }
+        }
+
         private void CalculateResponseFormats(ICollection<ApiResponseType> responseTypes, MediaTypeCollection declaredContentTypes)
         {
             var responseTypeMetadataProviders = _mvcOptions.OutputFormatters.OfType<IApiResponseTypeMetadataProvider>();
@@ -182,6 +194,9 @@ private void CalculateResponseFormats(ICollection<ApiResponseType> responseTypes
 
             foreach (var apiResponse in responseTypes)
             {
+                // ApiResponseFormats has been preset for EndpointMetadataApiDescriptionProvider's use but MVC has more inputs to consider.
+                apiResponse.ApiResponseFormats.Clear();
+
                 var responseType = apiResponse.Type;
                 if (responseType == null || responseType == typeof(void))
                 {

src/Mvc/Mvc.ApiExplorer/src/EndpointMetadataApiDescriptionProvider.cs

@@ -168,6 +168,12 @@ private static void AddSupportedResponseTypes(IList<ApiResponseType> supportedRe
                 responseType = awaitableInfo.ResultType;
             }
 
+            // Can't determine anything about IResults yet that's not from extra metadata. IResult<T> could help here.
+            if (typeof(IResult).IsAssignableFrom(responseType))
+            {
+                responseType = typeof(void);
+            }
+
             var responseMetadata = endpointMetadata.GetOrderedMetadata<IApiResponseMetadataProvider>();
             var errorMetadata = endpointMetadata.GetMetadata<ProducesErrorResponseTypeAttribute>();
             var defaultErrorType = errorMetadata?.Type ?? typeof(void);
@@ -179,7 +185,12 @@ private static void AddSupportedResponseTypes(IList<ApiResponseType> supportedRe
             {
                 foreach (var apiResponseType in responseMetadataTypes)
                 {
-                    AddApiResponseFormats(apiResponseType.ApiResponseFormats, contentTypes);
+                    if (apiResponseType.ApiResponseFormats.Count == 0 &&
+                        CreateDefaultApiResponseFormat(responseType) is { } defaultResponseFormat)
+                    {
+                        apiResponseType.ApiResponseFormats.Add(defaultResponseFormat);
+                    }
+
                     supportedResponseTypes.Add(apiResponseType);
                 }
             }
@@ -190,57 +201,47 @@ private static void AddSupportedResponseTypes(IList<ApiResponseType> supportedRe
 
                 if (contentTypes.Count > 0)
                 {
-                    // If metadata provided us with response formats, use that instead of the defaults.
+                    // If metadata provided us with response formats, use that instead of the default.
                     defaultApiResponseType.ApiResponseFormats.Clear();
-                    AddApiResponseFormats(defaultApiResponseType.ApiResponseFormats, contentTypes);
+                    ApiResponseTypeProvider.AddApiResponseFormats(defaultApiResponseType.ApiResponseFormats, contentTypes);
                 }
 
                 supportedResponseTypes.Add(defaultApiResponseType);
             }
         }
 
         private static ApiResponseType CreateDefaultApiResponseType(Type responseType)
+        {
+            var apiResponseType = new ApiResponseType
+            {
+                ModelMetadata = new EndpointModelMetadata(ModelMetadataIdentity.ForType(responseType)),
+                StatusCode = 200,
+            };
+
+            if (CreateDefaultApiResponseFormat(responseType) is { } responseFormat)
+            {
+                apiResponseType.ApiResponseFormats.Add(responseFormat);
+            }
+
+            return apiResponseType;
+        }
+
+        private static ApiResponseFormat? CreateDefaultApiResponseFormat(Type responseType)
         {
             if (responseType == typeof(void) || typeof(IResult).IsAssignableFrom(responseType))
             {
-                // Can't determine anything about IResults yet that's not from extra metadata. IResult<T> could help here.
-                return new ApiResponseType
-                {
-                    ModelMetadata = new EndpointModelMetadata(ModelMetadataIdentity.ForType(typeof(void))),
-                    StatusCode = 200,
-                };
+                return null;
             }
             else if (responseType == typeof(string))
             {
                 // This uses HttpResponse.WriteAsync(string) method which doesn't set a content type. It could be anything,
                 // but I think "text/plain" is a reasonable assumption if nothing else is specified with metadata.
-                return new ApiResponseType
-                {
-                    ApiResponseFormats = { new ApiResponseFormat { MediaType = "text/plain" } },
-                    ModelMetadata = new EndpointModelMetadata(ModelMetadataIdentity.ForType(typeof(string))),
-                    StatusCode = 200,
-                };
+                return new ApiResponseFormat { MediaType = "text/plain" };
             }
             else
             {
                 // Everything else is written using HttpResponse.WriteAsJsonAsync<TValue>(T).
-                return new ApiResponseType
-                {
-                    ApiResponseFormats = { new ApiResponseFormat { MediaType = "application/json" } },
-                    ModelMetadata = new EndpointModelMetadata(ModelMetadataIdentity.ForType(responseType)),
-                    StatusCode = 200,
-                };
-            }
-        }
-
-        private static void AddApiResponseFormats(IList<ApiResponseFormat> apiResponseFormats, MediaTypeCollection contentTypes)
-        {
-            foreach (var contentType in contentTypes)
-            {
-                apiResponseFormats.Add(new ApiResponseFormat
-                {
-                    MediaType = contentType,
-                });
+                return new ApiResponseFormat { MediaType = "application/json" };
             }
         }
     }