refactor(middlware): split concerns

move the middleware implementation into its own class, separate from the app builder extensions

Author: jaredcnance

src/JsonApiDotNetCore/Extensions/IApplicationBuilderExtensions.cs

@@ -1,67 +1,17 @@
+using JsonApiDotNetCore.Middleware;
 using Microsoft.AspNetCore.Builder;
-using Microsoft.AspNetCore.Http;
-using Microsoft.Extensions.Primitives;
 
 namespace JsonApiDotNetCore.Routing
 {
     public static class IApplicationBuilderExtensions
     {
         public static IApplicationBuilder UseJsonApi(this IApplicationBuilder app)
         {
-            app.Use(async (context, next) =>
-            {
-                if (IsValid(context))
-                    await next.Invoke();
-            });
+            app.UseMiddleware<RequestMiddleware>();
 
             app.UseMvc();
 
             return app;
         }
-
-        private static bool IsValid(HttpContext context)
-        {
-            return IsValidContentTypeHeader(context) && IsValidAcceptHeader(context);
-        }
-
-        private static bool IsValidContentTypeHeader(HttpContext context)
-        {
-            var contentType = context.Request.ContentType;
-            if (contentType != null && ContainsMediaTypeParameters(contentType))
-            {
-                FlushResponse(context, 415);
-                return false;
-            }
-            return true;
-        }
-
-        private static bool IsValidAcceptHeader(HttpContext context)
-        {
-            var acceptHeaders = new StringValues();
-            if (context.Request.Headers.TryGetValue("Accept", out acceptHeaders))
-            {
-                foreach (var acceptHeader in acceptHeaders)
-                {
-                    if (ContainsMediaTypeParameters(acceptHeader))
-                    {
-                        FlushResponse(context, 406);
-                        return false;
-                    }
-                }
-            }
-            return true;
-        }
-
-        private static bool ContainsMediaTypeParameters(string mediaType)
-        {
-            var mediaTypeArr = mediaType.Split(';');
-            return (mediaTypeArr[0] == "application/vnd.api+json" && mediaTypeArr.Length == 2);
-        }
-
-        private static void FlushResponse(HttpContext context, int statusCode)
-        {
-            context.Response.StatusCode = statusCode;
-            context.Response.Body.Flush();
-        }
     }
 }

src/JsonApiDotNetCore/Middleware/RequestMiddleware.cs

@@ -0,0 +1,67 @@
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Primitives;
+
+namespace JsonApiDotNetCore.Middleware
+{
+    public class RequestMiddleware
+    {
+        private readonly RequestDelegate _next;
+        
+        public RequestMiddleware(RequestDelegate next)
+        {
+            _next = next;
+        }
+
+        public async Task Invoke(HttpContext context)
+        {
+            if (IsValid(context))
+                await _next(context);
+        }
+
+        private static bool IsValid(HttpContext context)
+        {
+            return IsValidContentTypeHeader(context) && IsValidAcceptHeader(context);
+        }
+
+        private static bool IsValidContentTypeHeader(HttpContext context)
+        {
+            var contentType = context.Request.ContentType;
+            if (contentType != null && ContainsMediaTypeParameters(contentType))
+            {
+                FlushResponse(context, 415);
+                return false;
+            }
+            return true;
+        }
+
+        private static bool IsValidAcceptHeader(HttpContext context)
+        {
+            var acceptHeaders = new StringValues();
+            if (context.Request.Headers.TryGetValue("Accept", out acceptHeaders))
+            {
+                foreach (var acceptHeader in acceptHeaders)
+                {
+                    if (ContainsMediaTypeParameters(acceptHeader))
+                    {
+                        FlushResponse(context, 406);
+                        return false;
+                    }
+                }
+            }
+            return true;
+        }
+
+        private static bool ContainsMediaTypeParameters(string mediaType)
+        {
+            var mediaTypeArr = mediaType.Split(';');
+            return (mediaTypeArr[0] == "application/vnd.api+json" && mediaTypeArr.Length == 2);
+        }
+
+        private static void FlushResponse(HttpContext context, int statusCode)
+        {
+            context.Response.StatusCode = statusCode;
+            context.Response.Body.Flush();
+        }
+    }
+}