Adding Accept header optionality configuration (#52)

Author: tpeczek

Lib.AspNetCore.ServerSentEvents/ServerSentEventsMiddleware.cs

@@ -118,12 +118,12 @@ private bool CheckAcceptHeader(IHeaderDictionary requestHeaders)
         {
             if (!requestHeaders.ContainsKey(Constants.ACCEPT_HTTP_HEADER))
             {
-                return true;
+                return !_serverSentEventsOptions.RequireAcceptHeader;
             }
 
             if (requestHeaders[Constants.ACCEPT_HTTP_HEADER].Count == 0)
             {
-                return true;
+                return !_serverSentEventsOptions.RequireAcceptHeader;
             }
 
             if (requestHeaders[Constants.ACCEPT_HTTP_HEADER].Any(acceptHeaderValue => acceptHeaderValue == Constants.SSE_CONTENT_TYPE))

Lib.AspNetCore.ServerSentEvents/ServerSentEventsOptions.cs

@@ -26,5 +26,10 @@ public ServerSentEventsOptions()
         /// This can be used to add or change the response headers.
         /// </summary>
         public Action<HttpResponse> OnPrepareAccept { get; set; }
+
+        /// <summary>
+        /// Gets or sets the value indicating if Accept HTTP header with value of text/event-stream should be required.
+        /// </summary>
+        public bool RequireAcceptHeader { get; set; } = false;
     }
 }

Test.AspNetCore.ServerSentEvents/Unit/Middleware/HandshakeTests.cs

@@ -16,7 +16,7 @@ public class HandshakeTests
 
         #region Tests
         [Fact]
-        public async Task Invoke_SseRequestWithoutAcceptHeader_Accepts()
+        public async Task Invoke_SseRequestWithoutAcceptHeaderAndAcceptHeaderNotRequired_Accepts()
         {
             ServerSentEventsMiddleware<ServerSentEventsService> serverSentEventsMiddleware = SubjectUnderTestHelper.PrepareServerSentEventsMiddleware();
             HttpContext context = SubjectUnderTestHelper.PrepareHttpContext(acceptHeaderValue: null);
@@ -26,6 +26,17 @@ public async Task Invoke_SseRequestWithoutAcceptHeader_Accepts()
             Assert.Equal(SSE_CONTENT_TYPE, context.Response.ContentType);
         }
 
+        [Fact]
+        public async Task Invoke_SseRequestWithoutAcceptHeaderAndAcceptHeaderRequired_DoesNotAccept()
+        {
+            ServerSentEventsMiddleware<ServerSentEventsService> serverSentEventsMiddleware = SubjectUnderTestHelper.PrepareServerSentEventsMiddleware(options: new ServerSentEventsOptions { RequireAcceptHeader = true });
+            HttpContext context = SubjectUnderTestHelper.PrepareHttpContext(acceptHeaderValue: null);
+
+            await serverSentEventsMiddleware.Invoke(context, null);
+
+            Assert.Null(context.Response.ContentType);
+        }
+
         [Fact]
         public async Task Invoke_SseRequestWithEventStreamAcceptHeader_Accepts()
         {