Commonizing JSON writer/serializer code

This doesn't add any new extensibility, and will likely change again in
the future when we add extensibility. For now this is a stopgap to reduce
duplication between JsonResult and JsonViewComponentResult.

src/Microsoft.AspNet.Mvc.Core/ActionResults/JsonResult.cs

@@ -22,7 +22,7 @@ namespace Microsoft.AspNet.Mvc
             }
 
             _returnValue = returnValue;
-            _jsonSerializerSettings = CreateSerializerSettings();
+            _jsonSerializerSettings = JsonOutputFormatter.CreateDefaultSettings();
         }
 
         public JsonSerializerSettings SerializerSettings
@@ -70,45 +70,11 @@ namespace Microsoft.AspNet.Mvc
                 response.ContentType = "application/json";
             }
 
-            using (JsonWriter jsonWriter = CreateJsonWriter(writeStream, Encoding))
+            using (var writer = new StreamWriter(writeStream, Encoding, 1024, leaveOpen: true))
             {
-                jsonWriter.CloseOutput = false;
+                var formatter = new JsonOutputFormatter(SerializerSettings, Indent);
-
+                formatter.WriteObject(writer, _returnValue);
-                JsonSerializer jsonSerializer = CreateJsonSerializer();
-                jsonSerializer.Serialize(jsonWriter, _returnValue);
-
-                jsonWriter.Flush();
             }
         }
-
-        private JsonSerializerSettings CreateSerializerSettings()
-        {
-            return new JsonSerializerSettings()
-            {
-                MissingMemberHandling = MissingMemberHandling.Ignore,
-
-                // Do not change this setting
-                // Setting this to None prevents Json.NET from loading malicious, unsafe, or security-sensitive types.
-                TypeNameHandling = TypeNameHandling.None
-            };
-        }
-
-        private JsonSerializer CreateJsonSerializer()
-        {
-            JsonSerializer jsonSerializer = JsonSerializer.Create(SerializerSettings);
-
-            return jsonSerializer;
-        }
-
-        private JsonWriter CreateJsonWriter(Stream writeStream, Encoding effectiveEncoding)
-        {
-            JsonWriter jsonWriter = new JsonTextWriter(new StreamWriter(writeStream, effectiveEncoding));
-            if (Indent)
-            {
-                jsonWriter.Formatting = Formatting.Indented;
-            }
-
-            return jsonWriter;
-        }
     }
 }

src/Microsoft.AspNet.Mvc.Core/JsonOutputFormatter.cs

@@ -0,0 +1,63 @@
+
+using System.IO;
+using Newtonsoft.Json;
+
+namespace Microsoft.AspNet.Mvc
+{
+    public class JsonOutputFormatter
+    {
+        private readonly JsonSerializerSettings _settings;
+        private readonly bool _indent;
+
+        public JsonOutputFormatter([NotNull] JsonSerializerSettings settings, bool indent)
+        {
+            _settings = settings;
+            _indent = indent;
+        }
+
+        public static JsonSerializerSettings CreateDefaultSettings()
+        {
+            return new JsonSerializerSettings()
+            {
+                MissingMemberHandling = MissingMemberHandling.Ignore,
+
+                // Do not change this setting
+                // Setting this to None prevents Json.NET from loading malicious, unsafe, or security-sensitive types.
+                TypeNameHandling = TypeNameHandling.None
+            };
+        }
+
+        public void WriteObject([NotNull] TextWriter writer, object value)
+        {
+            using (var jsonWriter = CreateJsonWriter(writer))
+            {
+                var jsonSerializer = CreateJsonSerializer();
+                jsonSerializer.Serialize(jsonWriter, value);
+
+                // We're explicitly calling flush here to simplify the debugging experience because the
+                // underlying TextWriter might be long-lived. If this method ends up being called repeatedly
+                // for a request, we should revisit.
+                jsonWriter.Flush();
+            }
+        }
+
+        private JsonWriter CreateJsonWriter([NotNull] TextWriter writer)
+        {
+            var jsonWriter = new JsonTextWriter(writer);
+            if (_indent)
+            {
+                jsonWriter.Formatting = Formatting.Indented;
+            }
+
+            jsonWriter.CloseOutput = false;
+
+            return jsonWriter;
+        }
+
+        private JsonSerializer CreateJsonSerializer()
+        {
+            var jsonSerializer = JsonSerializer.Create(_settings);
+            return jsonSerializer;
+        }
+    }
+}

src/Microsoft.AspNet.Mvc.Core/ViewComponents/JsonViewComponentResult.cs

@@ -1,6 +1,5 @@
 
 using System;
-using System.IO;
 using System.Threading.Tasks;
 using Newtonsoft.Json;
 
@@ -15,7 +14,7 @@ namespace Microsoft.AspNet.Mvc
         public JsonViewComponentResult([NotNull] object value)
         {
             _value = value;
-            _jsonSerializerSettings = CreateSerializerSettings();
+            _jsonSerializerSettings = JsonOutputFormatter.CreateDefaultSettings();
         }
 
         public JsonSerializerSettings SerializerSettings
@@ -38,46 +37,10 @@ namespace Microsoft.AspNet.Mvc
         /// </summary>
         public bool Indent { get; set; }
 
-        private JsonSerializerSettings CreateSerializerSettings()
-        {
-            return new JsonSerializerSettings()
-            {
-                MissingMemberHandling = MissingMemberHandling.Ignore,
-
-                // Do not change this setting
-                // Setting this to None prevents Json.NET from loading malicious, unsafe, or security-sensitive types.
-                TypeNameHandling = TypeNameHandling.None
-            };
-        }
-
-        private JsonSerializer CreateJsonSerializer()
-        {
-            var jsonSerializer = JsonSerializer.Create(SerializerSettings);
-            return jsonSerializer;
-        }
-
-        private JsonWriter CreateJsonWriter([NotNull] TextWriter writer)
-        {
-            var jsonWriter = new JsonTextWriter(writer);
-            if (Indent)
-            {
-                jsonWriter.Formatting = Formatting.Indented;
-            }
-
-            return jsonWriter;
-        }
-
         public void Execute([NotNull] ViewComponentContext context)
         {
-            using (var jsonWriter = CreateJsonWriter(context.Writer))
+            var formatter = new JsonOutputFormatter(SerializerSettings, Indent);
-            {
+            formatter.WriteObject(context.Writer, _value);
-                jsonWriter.CloseOutput = false;
-
-                var jsonSerializer = CreateJsonSerializer();
-                jsonSerializer.Serialize(jsonWriter, _value);
-
-                jsonWriter.Flush();
-            }
         }
 
         public async Task ExecuteAsync([NotNull] ViewComponentContext context)