[Fixes 7139] Add format filter mapping for xml formatters

src/Microsoft.AspNetCore.Mvc.Formatters.Json/Internal/MvcJsonMvcOptionsSetup.cs

@@ -80,7 +80,7 @@ namespace Microsoft.AspNetCore.Mvc.Formatters.Json.Internal
                 options,
                 _jsonOptions));
 
-            options.FormatterMappings.SetMediaTypeMappingForFormat("json", MediaTypeHeaderValue.Parse("application/json"));
+            options.FormatterMappings.SetMediaTypeMappingForFormat("json", MediaTypeHeaderValues.ApplicationJson);
 
             options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(IJsonPatchDocument)));
             options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(JToken)));

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/Internal/MvcXmlDataContractSerializerMvcOptionsSetup.cs

@@ -6,6 +6,7 @@ using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Metadata;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using Microsoft.Net.Http.Headers;
 
 namespace Microsoft.AspNetCore.Mvc.Formatters.Xml.Internal
 {
@@ -42,6 +43,16 @@ namespace Microsoft.AspNetCore.Mvc.Formatters.Xml.Internal
             options.OutputFormatters.Add(new XmlDataContractSerializerOutputFormatter(_loggerFactory));
             options.InputFormatters.Add(new XmlDataContractSerializerInputFormatter(options));
 
+            // Do not override any user mapping
+            var key = "xml";
+            var mapping = options.FormatterMappings.GetMediaTypeMappingForFormat(key);
+            if (string.IsNullOrEmpty(mapping))
+            {
+                options.FormatterMappings.SetMediaTypeMappingForFormat(
+                    key,
+                    MediaTypeHeaderValues.ApplicationXml);
+            }
+
             options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider("System.Xml.Linq.XObject"));
             options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider("System.Xml.XmlNode"));
         }

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/Internal/MvcXmlSerializerMvcOptionsSetup.cs

@@ -4,6 +4,7 @@
 using System;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using Microsoft.Net.Http.Headers;
 
 namespace Microsoft.AspNetCore.Mvc.Formatters.Xml.Internal
 {
@@ -35,6 +36,16 @@ namespace Microsoft.AspNetCore.Mvc.Formatters.Xml.Internal
         /// <param name="options">The <see cref="MvcOptions"/>.</param>
         public void Configure(MvcOptions options)
         {
+            // Do not override any user mapping
+            var key = "xml";
+            var mapping = options.FormatterMappings.GetMediaTypeMappingForFormat(key);
+            if (string.IsNullOrEmpty(mapping))
+            {
+                options.FormatterMappings.SetMediaTypeMappingForFormat(
+                    key,
+                    MediaTypeHeaderValues.ApplicationXml);
+            }
+
             options.OutputFormatters.Add(new XmlSerializerOutputFormatter(_loggerFactory));
             options.InputFormatters.Add(new XmlSerializerInputFormatter(options));
         }

test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/Internal/MvcXmlDataContractSerializerMvcOptionsSetupTest.cs

@@ -0,0 +1,42 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.Extensions.Logging.Abstractions;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Formatters.Xml.Internal
+{
+    public class MvcXmlDataContractSerializerMvcOptionsSetupTest
+    {
+        [Fact]
+        public void AddsFormatterMapping()
+        {
+            // Arrange
+            var optionsSetup = new MvcXmlDataContractSerializerMvcOptionsSetup(NullLoggerFactory.Instance);
+            var options = new MvcOptions();
+
+            // Act
+            optionsSetup.Configure(options);
+
+            // Assert
+            var mappedContentType = options.FormatterMappings.GetMediaTypeMappingForFormat("xml");
+            Assert.Equal("application/xml", mappedContentType);
+        }
+
+        [Fact]
+        public void DoesNotOverrideExistingMapping()
+        {
+            // Arrange
+            var optionsSetup = new MvcXmlDataContractSerializerMvcOptionsSetup(NullLoggerFactory.Instance);
+            var options = new MvcOptions();
+            options.FormatterMappings.SetMediaTypeMappingForFormat("xml", "text/xml");
+
+            // Act
+            optionsSetup.Configure(options);
+
+            // Assert
+            var mappedContentType = options.FormatterMappings.GetMediaTypeMappingForFormat("xml");
+            Assert.Equal("text/xml", mappedContentType);
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/Internal/MvcXmlSerializerMvcOptionsSetupTest.cs

@@ -0,0 +1,42 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.Extensions.Logging.Abstractions;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Formatters.Xml.Internal
+{
+    public class MvcXmlSerializerMvcOptionsSetupTest
+    {
+        [Fact]
+        public void AddsFormatterMapping()
+        {
+            // Arrange
+            var optionsSetup = new MvcXmlSerializerMvcOptionsSetup(NullLoggerFactory.Instance);
+            var options = new MvcOptions();
+
+            // Act
+            optionsSetup.Configure(options);
+
+            // Assert
+            var mappedContentType = options.FormatterMappings.GetMediaTypeMappingForFormat("xml");
+            Assert.Equal("application/xml", mappedContentType);
+        }
+
+        [Fact]
+        public void DoesNotOverrideExistingMapping()
+        {
+            // Arrange
+            var optionsSetup = new MvcXmlSerializerMvcOptionsSetup(NullLoggerFactory.Instance);
+            var options = new MvcOptions();
+            options.FormatterMappings.SetMediaTypeMappingForFormat("xml", "text/xml");
+
+            // Act
+            optionsSetup.Configure(options);
+
+            // Assert
+            var mappedContentType = options.FormatterMappings.GetMediaTypeMappingForFormat("xml");
+            Assert.Equal("text/xml", mappedContentType);
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.FunctionalTests/ContentNegotiationTest.cs

@@ -450,13 +450,12 @@ END:VCARD
         [Fact]
         public async Task ProducesAttribute_And_FormatFilterAttribute_Conflicting()
         {
-            // Arrange
+            // Arrange & Act
-            var expectedContentType = MediaTypeHeaderValue.Parse("application/json");
+            var response = await Client.GetAsync(
-
+                "http://localhost/FormatFilter/ProducesTakesPrecedenceOverUserSuppliedFormatMethod?format=json");
-            // Act
-            var response = await Client.GetAsync("http://localhost/FormatFilter/MethodWithFormatFilter.json");
 
             // Assert
+            // Explicit content type set by the developer takes precedence over the format requested by the end user
             Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
         }
 
@@ -464,7 +463,8 @@ END:VCARD
         public async Task ProducesAttribute_And_FormatFilterAttribute_Collaborating()
         {
             // Arrange & Act
-            var response = await Client.GetAsync("http://localhost/FormatFilter/MethodWithFormatFilter");
+            var response = await Client.GetAsync(
+                "http://localhost/FormatFilter/ProducesTakesPrecedenceOverUserSuppliedFormatMethod");
 
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
@@ -508,5 +508,24 @@ END:VCARD
             var contact = xmlDeserializer.ReadObject(bodyStream) as Contact;
             Assert.Equal("Jason Ecsemelle", contact.Name);
         }
+
+        [Fact]
+        public async Task FormatFilter_XmlAsFormat_ReturnsXml()
+        {
+            // Arrange
+            var expectedBody = "<FormatFilterController.Customer xmlns:i=\"http://www.w3.org/2001/XMLSchema-instance\""
+                + " xmlns=\"http://schemas.datacontract.org/2004/07/BasicWebSite.Controllers.ContentNegotiation\">"
+                + "<Name>John</Name></FormatFilterController.Customer>";
+
+            // Act
+            var response = await Client.GetAsync(
+                "http://localhost/FormatFilter/CustomerInfo?format=xml");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+            Assert.Equal("application/xml; charset=utf-8", response.Content.Headers.ContentType.ToString());
+            var body = await response.Content.ReadAsStringAsync();
+            Assert.Equal(expectedBody, body);
+        }
     }
 }

test/WebSites/BasicWebSite/Controllers/ContentNegotiation/FormatFilterController.cs

@@ -7,24 +7,39 @@ using Microsoft.AspNetCore.Mvc.Filters;
 
 namespace BasicWebSite.Controllers.ContentNegotiation
 {
-    [Produces("application/FormatFilterController")]
     public class FormatFilterController : Controller
     {
-        public override void OnActionExecuted(ActionExecutedContext context)
+        [Produces("application/FormatFilterController")]
-        {
-            var result = context.Result as ObjectResult;
-            if (result != null)
-            {
-                result.Formatters.Add(new CustomFormatter("application/FormatFilterController"));
-            }
-
-            base.OnActionExecuted(context);
-        }
-
         [FormatFilter]
-        public string MethodWithFormatFilter()
+        [CustomFormatterActionFilter]
+        public string ProducesTakesPrecedenceOverUserSuppliedFormatMethod()
         {
             return "MethodWithFormatFilter";
         }
+
+        [HttpGet]
+        [FormatFilter]
+        public Customer CustomerInfo()
+        {
+            return new Customer() { Name = "John" };
+        }
+
+        private class CustomFormatterActionFilter : ActionFilterAttribute
+        {
+            public override void OnActionExecuted(ActionExecutedContext context)
+            {
+                var result = context.Result as ObjectResult;
+                if (result != null)
+                {
+                    result.Formatters.Add(new CustomFormatter("application/FormatFilterController"));
+                }
+            }
+        }
+
+        public class Customer
+        {
+            public string Name { get; set; }
+        }
     }
+
 }