add benchmarks to RequestMiddleware

Author: jaredcnance

benchmarks/BenchmarkDotNet.Artifacts/results/Benchmarks.RequestMiddleware.ContainsMediaTypeParameters_Benchmarks-report-github.md

@@ -0,0 +1,14 @@
+``` ini
+
+BenchmarkDotNet=v0.10.10, OS=Mac OS X 10.12
+Processor=Intel Core i5-5257U CPU 2.70GHz (Broadwell), ProcessorCount=4
+.NET Core SDK=2.1.4
+  [Host]     : .NET Core 2.0.5 (Framework 4.6.0.0), 64bit RyuJIT
+  DefaultJob : .NET Core 2.0.5 (Framework 4.6.0.0), 64bit RyuJIT
+
+
+```
+|     Method |      Mean |     Error |    StdDev |  Gen 0 | Allocated |
+|----------- |----------:|----------:|----------:|-------:|----------:|
+| UsingSplit | 157.28 ns | 2.9689 ns | 5.8602 ns | 0.2134 |     336 B |
+|    Current |  39.96 ns | 0.6489 ns | 0.6070 ns |      - |       0 B |

benchmarks/Program.cs

@@ -1,6 +1,7 @@
 using BenchmarkDotNet.Running;
 using Benchmarks.LinkBuilder;
 using Benchmarks.Query;
+using Benchmarks.RequestMiddleware;
 using Benchmarks.Serialization;
 
 namespace Benchmarks {
@@ -10,7 +11,8 @@ static void Main(string[] args) {
                 typeof(JsonApiDeserializer_Benchmarks),
                 typeof(JsonApiSerializer_Benchmarks),
                 typeof(QueryParser_Benchmarks),
-                typeof(LinkBuilder_GetNamespaceFromPath_Benchmarks)
+                typeof(LinkBuilder_GetNamespaceFromPath_Benchmarks),
+                typeof(ContainsMediaTypeParameters_Benchmarks)
             });
             switcher.Run(args);
         }

benchmarks/RequestMiddleware/ContainsMediaTypeParameters_Benchmarks.cs

@@ -0,0 +1,26 @@
+using System;
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Attributes.Exporters;
+using JsonApiDotNetCore.Internal;
+
+namespace Benchmarks.RequestMiddleware
+{
+    [MarkdownExporter, MemoryDiagnoser]
+    public class ContainsMediaTypeParameters_Benchmarks
+    {
+        private const string MEDIA_TYPE = "application/vnd.api+json; version=1";
+
+        [Benchmark]
+        public void UsingSplit() => UsingSplitImpl(MEDIA_TYPE);
+
+        [Benchmark]
+        public void Current() 
+            => JsonApiDotNetCore.Middleware.RequestMiddleware.ContainsMediaTypeParameters(MEDIA_TYPE);
+
+        private bool UsingSplitImpl(string mediaType)
+        {
+            var mediaTypeArr = mediaType.Split(';');
+            return (mediaTypeArr[0] ==  Constants.ContentType && mediaTypeArr.Length == 2);	
+        }
+    }
+}

src/JsonApiDotNetCore/Middleware/RequestMiddleware.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Threading.Tasks;
-using JsonApiDotNetCore.Extensions;
 using JsonApiDotNetCore.Internal;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Primitives;
@@ -54,12 +53,23 @@ private static bool IsValidAcceptHeader(HttpContext context)
             return true;
         }
 
-        private static bool ContainsMediaTypeParameters(string mediaType)
+        internal static bool ContainsMediaTypeParameters(string mediaType)
         {
-            const char delimeter = ';';
-            var subSpans = mediaType.SpanSplit(delimeter);
-            if (subSpans.Count == 0) return false;
-            return subSpans.Count == 2 && subSpans[0].ToString() == Constants.ContentType;
+            var incomingMediaTypeSpan = mediaType.AsSpan();
+
+            // if the content type is not application/vnd.api+json then continue on
+            if(incomingMediaTypeSpan.Length < Constants.ContentType.Length)
+                return false;
+
+            var incomingContentType = incomingMediaTypeSpan.Slice(0, Constants.ContentType.Length);
+            if(incomingContentType.SequenceEqual(Constants.ContentType.AsSpan()) == false)
+                return false;
+
+            // anything appended to "application/vnd.api+json;" will be considered a media type param
+            return (
+                incomingMediaTypeSpan.Length >= Constants.ContentType.Length + 2
+                && incomingMediaTypeSpan[Constants.ContentType.Length] == ';'
+            );
         }
 
         private static void FlushResponse(HttpContext context, int statusCode)