Adding TextPlainFormatter to always handle returning strings as text\plain format.

Author: harshgMSFT

src/Microsoft.AspNet.Mvc.Core/Formatters/TextPlainFormatter.cs

@@ -0,0 +1,53 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNet.Http;
+using Microsoft.AspNet.Mvc;
+using Microsoft.AspNet.Mvc.HeaderValueAbstractions;
+
+namespace Microsoft.AspNet.Mvc
+{
+    /// <summary>
+    /// Writes a string value to the response.
+    /// </summary>
+    public class TextPlainFormatter : OutputFormatter
+    {
+        public TextPlainFormatter()
+        {
+            SupportedMediaTypes.Add(MediaTypeHeaderValue.Parse("text/plain"));
+            SupportedEncodings.Add(Encoding.GetEncoding("utf-8"));
+        }
+        
+        public override bool CanWriteResult(OutputFormatterContext context, MediaTypeHeaderValue contentType)
+        {
+            if (base.CanWriteResult(context, contentType))
+            {
+                var valueAsString = context.Object as string;
+                if (valueAsString != null)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        public override void WriteResponseContentHeaders(OutputFormatterContext context)
+        {
+            // Ignore the accept-charset field, as this will always write utf-8.
+            var response = context.ActionContext.HttpContext.Response;            
+            response.ContentType = "text/plain;charset=utf-8";
+        }
+
+        public override async Task WriteResponseBodyAsync(OutputFormatterContext context)
+        {
+            var response = context.ActionContext.HttpContext.Response;
+            var valueAsString = context.Object as string;
+            await response.WriteAsync(valueAsString);
+        }
+    }
+}

src/Microsoft.AspNet.Mvc.Core/Microsoft.AspNet.Mvc.Core.kproj

@@ -33,6 +33,7 @@
     <Compile Include="Extensions\ViewEngineDescriptorExtensions.cs" />
     <Compile Include="Formatters\DefaultOutputFormattersProvider.cs" />
     <Compile Include="Formatters\IOutputFormatter.cs" />
+    <Compile Include="Formatters\TextPlainFormatter.cs" />
     <Compile Include="Formatters\StringWithQualityHeaderValueComparer.cs" />
     <Compile Include="IExpiringFileInfoCache.cs" />
     <Compile Include="Formatters\IOutputFormattersProvider.cs" />

src/Microsoft.AspNet.Mvc/MvcOptionsSetup.cs

@@ -33,6 +33,7 @@ public void Setup(MvcOptions options)
             options.ModelBinders.Add(new ComplexModelDtoModelBinder());
 
             // Set up default output formatters.
+            options.OutputFormatters.Add(new TextPlainFormatter());
             options.OutputFormatters.Add(new JsonOutputFormatter(JsonOutputFormatter.CreateDefaultSettings(), true));
 
             // Set up ValueProviders

test/Microsoft.AspNet.Mvc.Core.Test/ActionResults/ObjectContentResultTests.cs

@@ -309,29 +309,29 @@ public async Task ObjectResult_NoFormatterFound_Returns406()
             httpResponse.VerifySet(r => r.StatusCode = 406);
         }
 
-        // TODO: Disabling since this scenario is no longer dealt with in object result. 
-        // Re-enable once we do. 
-        //[Fact]
+        [Fact]
         public async Task ObjectResult_Execute_CallsContentResult_SetsContent()
         {
             // Arrange
-            var expectedContentType = "text/plain";
+            var expectedContentType = "text/plain;charset=utf-8";
             var input = "testInput";
             var stream = new MemoryStream();
 
             var httpResponse = new Mock<HttpResponse>();
-            var tempContentType = string.Empty;
             httpResponse.SetupProperty<string>(o => o.ContentType);
             httpResponse.SetupGet(r => r.Body).Returns(stream);
 
-            var actionContext = CreateMockActionContext(httpResponse.Object);
+            var actionContext = CreateMockActionContext(httpResponse.Object,
+                                                        requestAcceptHeader: null,
+                                                        requestContentType: null);
 
             // Act
             var result = new ObjectResult(input);
             await result.ExecuteResultAsync(actionContext);
 
             // Assert
             httpResponse.VerifySet(r => r.ContentType = expectedContentType);
+
             // The following verifies the correct Content was written to Body
             Assert.Equal(input.Length, httpResponse.Object.Body.Length);
         }
@@ -473,7 +473,10 @@ public IReadOnlyList<IOutputFormatter> OutputFormatters
                 get
                 {
                     return new List<IOutputFormatter>()
-                        { new JsonOutputFormatter(JsonOutputFormatter.CreateDefaultSettings(), indent: true) };
+                        {
+                            new TextPlainFormatter(),
+                            new JsonOutputFormatter(JsonOutputFormatter.CreateDefaultSettings(), indent: true)
+                        };
                 }
             }
         }

test/Microsoft.AspNet.Mvc.Test/MvcOptionSetupTest.cs

@@ -72,8 +72,9 @@ public void Setup_SetsUpOutputFormatters()
             setup.Setup(mvcOptions);
 
             // Assert
-            Assert.Equal(1, mvcOptions.OutputFormatters.Count);
-            Assert.IsType<JsonOutputFormatter>(mvcOptions.OutputFormatters[0].OutputFormatter);
+            Assert.Equal(2, mvcOptions.OutputFormatters.Count);
+            Assert.IsType<TextPlainFormatter>(mvcOptions.OutputFormatters[0].OutputFormatter);
+            Assert.IsType<JsonOutputFormatter>(mvcOptions.OutputFormatters[1].OutputFormatter);
         }
     }
 }