Prioritize wildcard over json over first entry for accept content-type (#5198)

Author: mdi1984

src/NSwag.CodeGeneration.Tests/CodeGenerationTests.cs

@@ -306,6 +306,69 @@ public void When_using_MultipleClientsFromOperationId_then_ensure_that_underscor
             Assert.Equal(expectedClientName, clientName);
         }
 
+        [Fact]
+        public void When_Success_Response_contains_multiple_content_types_prioritizes_wildcard()
+        {
+            // Arrange
+            var document = CreateDocument();
+            var operation = document.Paths["/Person"][OpenApiOperationMethod.Get];
+
+            operation.Responses["200"].Content.Clear();
+
+            operation.Responses["200"].Content.Add("application/xml", new OpenApiMediaType
+            {
+                Schema = new JsonSchema { Type = JsonObjectType.Object }
+            });
+
+            operation.Responses["200"].Content.Add("application/json", new OpenApiMediaType
+            {
+                Schema = new JsonSchema { Type = JsonObjectType.Object }
+            });
+
+            operation.Responses["200"].Content.Add("*/*", new OpenApiMediaType
+            {
+                Schema = new JsonSchema { Type = JsonObjectType.Object }
+            });
+
+            // Act
+            var settings = new CSharpClientGeneratorSettings();
+            settings.CSharpGeneratorSettings.JsonLibrary = NJsonSchema.CodeGeneration.CSharp.CSharpJsonLibrary.SystemTextJson;
+            var generator = new CSharpClientGenerator(document, settings);
+            var code = generator.GenerateFile();
+
+            // Assert
+            Assert.Contains("Headers.Accept.Add(System.Net.Http.Headers.MediaTypeWithQualityHeaderValue.Parse(\"*/*\"));", code);
+        }
+
+        [Fact]
+        public void When_Success_Response_contains_multiple_content_types_prioritizes_json()
+        {
+            // Arrange
+            var document = CreateDocument();
+            var operation = document.Paths["/Person"][OpenApiOperationMethod.Get];
+
+            operation.Responses["200"].Content.Clear();
+
+            operation.Responses["200"].Content.Add("application/xml", new OpenApiMediaType
+            {
+                Schema = new JsonSchema { Type = JsonObjectType.Object }
+            });
+
+            operation.Responses["200"].Content.Add("application/json", new OpenApiMediaType
+            {
+                Schema = new JsonSchema { Type = JsonObjectType.Object }
+            });
+
+            // Act
+            var settings = new CSharpClientGeneratorSettings();
+            settings.CSharpGeneratorSettings.JsonLibrary = NJsonSchema.CodeGeneration.CSharp.CSharpJsonLibrary.SystemTextJson;
+            var generator = new CSharpClientGenerator(document, settings);
+            var code = generator.GenerateFile();
+
+            // Assert
+            Assert.Contains("Headers.Accept.Add(System.Net.Http.Headers.MediaTypeWithQualityHeaderValue.Parse(\"application/json\"));", code);
+        }
+
         private static OpenApiDocument CreateDocument()
         {
             var document = new OpenApiDocument();

src/NSwag.CodeGeneration/Models/ResponseModelBase.cs

@@ -124,6 +124,9 @@ public bool IsSuccess
         public IDictionary<string, object> ExtensionData => _response.ExtensionData;
 
         /// <summary>Gets the produced mime type of this response if available.</summary>
-        public string Produces => _response.Content.Keys.FirstOrDefault();
+        public string Produces =>
+            _response.Content.Keys.FirstOrDefault(k => k == "*/*") ??
+            _response.Content.Keys.FirstOrDefault(k => k == "application/json") ??
+            _response.Content.Keys.FirstOrDefault();
     }
 }