[Fixes #2541] Use custom stream writer for Xml output formatters

Author: kichalla

src/Microsoft.AspNet.Mvc.Xml/XmlDataContractSerializerOutputFormatter.cs

@@ -158,7 +158,9 @@ protected virtual DataContractSerializer CreateSerializer([NotNull] Type type)
         public virtual XmlWriter CreateXmlWriter([NotNull] Stream writeStream,
                                                  [NotNull] XmlWriterSettings xmlWriterSettings)
         {
-            return XmlWriter.Create(writeStream, xmlWriterSettings);
+            return XmlWriter.Create(
+                new HttpResponseStreamWriter(writeStream, xmlWriterSettings.Encoding),
+                xmlWriterSettings);
         }
 
         /// <inheritdoc />
@@ -167,10 +169,7 @@ public override Task WriteResponseBodyAsync([NotNull] OutputFormatterContext con
             var tempWriterSettings = WriterSettings.Clone();
             tempWriterSettings.Encoding = context.SelectedEncoding;
 
-            var innerStream = context.HttpContext.Response.Body;
-
-            using (var outputStream = new NonDisposableStream(innerStream))
-            using (var xmlWriter = CreateXmlWriter(outputStream, tempWriterSettings))
+            using (var xmlWriter = CreateXmlWriter(context.HttpContext.Response.Body, tempWriterSettings))
             {
                 var obj = context.Object;
                 var runtimeType = obj?.GetType();

src/Microsoft.AspNet.Mvc.Xml/XmlSerializerOutputFormatter.cs

@@ -133,7 +133,9 @@ protected virtual XmlSerializer CreateSerializer([NotNull] Type type)
         public virtual XmlWriter CreateXmlWriter([NotNull] Stream writeStream,
                                                  [NotNull] XmlWriterSettings xmlWriterSettings)
         {
-            return XmlWriter.Create(writeStream, xmlWriterSettings);
+            return XmlWriter.Create(
+                new HttpResponseStreamWriter(writeStream, xmlWriterSettings.Encoding),
+                xmlWriterSettings);
         }
 
         /// <inheritdoc />
@@ -144,10 +146,7 @@ public override Task WriteResponseBodyAsync([NotNull] OutputFormatterContext con
             var tempWriterSettings = WriterSettings.Clone();
             tempWriterSettings.Encoding = context.SelectedEncoding;
 
-            var innerStream = context.HttpContext.Response.Body;
-
-            using (var outputStream = new NonDisposableStream(innerStream))
-            using (var xmlWriter = CreateXmlWriter(outputStream, tempWriterSettings))
+            using (var xmlWriter = CreateXmlWriter(context.HttpContext.Response.Body, tempWriterSettings))
             {
                 var obj = context.Object;
                 var runtimeType = obj?.GetType();

test/Microsoft.AspNet.Mvc.Xml.Test/XmlDataContractSerializerOutputFormatterTest.cs

@@ -272,7 +272,9 @@ public async Task WriteAsync_WritesUTF16Output()
             var body = outputFormatterContext.HttpContext.Response.Body;
             body.Position = 0;
 
-            var content = new StreamReader(body).ReadToEnd();
+            var content = new StreamReader(
+                body,
+                new UnicodeEncoding(bigEndian: false, byteOrderMark: false, throwOnInvalidBytes: true)).ReadToEnd();
             XmlAssert.Equal(expectedOutput, content);
         }
 

test/Microsoft.AspNet.Mvc.Xml.Test/XmlSerializerOutputFormatterTest.cs

@@ -227,8 +227,9 @@ public async Task XmlSerializerOutputFormatterWritesUTF16Output()
             // Assert
             var body = outputFormatterContext.HttpContext.Response.Body;
             body.Position = 0;
-
-            var content = new StreamReader(body).ReadToEnd();
+            var content = new StreamReader(
+                body,
+                new UnicodeEncoding(bigEndian: false, byteOrderMark: false, throwOnInvalidBytes: true)).ReadToEnd();
             XmlAssert.Equal(expectedOutput, content);
         }
 

test/WebSites/ContentNegotiationWebSite/VCardFormatter_V3.cs

@@ -7,6 +7,7 @@
 using System.Text;
 using System.Threading.Tasks;
 using ContentNegotiationWebSite.Models;
+using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Mvc;
 using Microsoft.AspNet.Mvc.Internal;
 using Microsoft.Net.Http.Headers;
@@ -39,11 +40,7 @@ public override async Task WriteResponseBodyAsync(OutputFormatterContext context
             builder.AppendLine();
             builder.AppendLine("END:VCARD");
 
-            var responseStream = new NonDisposableStream(context.HttpContext.Response.Body);
-            using (var writer = new StreamWriter(responseStream, context.SelectedEncoding, bufferSize: 1024))
-            {
-                await writer.WriteAsync(builder.ToString());
-            }
+            await context.HttpContext.Response.WriteAsync(builder.ToString(), context.SelectedEncoding);
         }
     }
 }

test/WebSites/ContentNegotiationWebSite/VCardFormatter_V4.cs

@@ -7,6 +7,7 @@
 using System.Text;
 using System.Threading.Tasks;
 using ContentNegotiationWebSite.Models;
+using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Mvc;
 using Microsoft.AspNet.Mvc.Internal;
 using Microsoft.Net.Http.Headers;
@@ -42,11 +43,7 @@ public override async Task WriteResponseBodyAsync(OutputFormatterContext context
             builder.AppendLine();
             builder.AppendLine("END:VCARD");
 
-            var responseStream = new NonDisposableStream(context.HttpContext.Response.Body);
-            using (var writer = new StreamWriter(responseStream, context.SelectedEncoding, bufferSize: 1024))
-            {
-                await writer.WriteAsync(builder.ToString());
-            }
+            await context.HttpContext.Response.WriteAsync(builder.ToString(), context.SelectedEncoding);
         }
     }
 }