Handle wildcard headers

Update ServerSentEventsMiddleware.cs

Author: Tobias Mønster

Lib.AspNetCore.ServerSentEvents/ServerSentEventsMiddleware.cs

@@ -114,6 +114,8 @@ public async Task Invoke(HttpContext context, IPolicyEvaluator policyEvaluator)
             }
         }
 
+        private static readonly string[] AcceptedHeaders = new[] { "*/*", "text/*", Constants.SSE_CONTENT_TYPE };
+        
         private bool CheckAcceptHeader(IHeaderDictionary requestHeaders)
         {
             if (!requestHeaders.ContainsKey(Constants.ACCEPT_HTTP_HEADER))
@@ -126,7 +128,7 @@ private bool CheckAcceptHeader(IHeaderDictionary requestHeaders)
                 return !_serverSentEventsOptions.RequireAcceptHeader;
             }
 
-            if (requestHeaders.GetCommaSeparatedValues(Constants.ACCEPT_HTTP_HEADER).Any(acceptHeaderValue => acceptHeaderValue == Constants.SSE_CONTENT_TYPE))
+            if (requestHeaders.GetCommaSeparatedValues(Constants.ACCEPT_HTTP_HEADER).Any(acceptHeaderValue => AcceptedHeaders.Contains(acceptHeaderValue)))
             {
                 return true;
             }

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

@@ -95,6 +95,21 @@ public async Task Invoke_SseRequestWithMultipleAcceptHeadersWithNotEventStreamAc
             Assert.Null(context.Response.ContentType);
         }
 
+        
+        [Theory]
+        [InlineData("*/*")]
+        [InlineData("text/*")]
+        [InlineData(SSE_CONTENT_TYPE)]
+        public async Task Invoke_SseRequestWithAcceptedHeader_Accepts(string header)
+        {
+            ServerSentEventsMiddleware<ServerSentEventsService> serverSentEventsMiddleware = SubjectUnderTestHelper.PrepareServerSentEventsMiddleware();
+            HttpContext context = SubjectUnderTestHelper.PrepareHttpContext(acceptHeaderValue: header);
+
+            await serverSentEventsMiddleware.Invoke(context, null);
+
+            Assert.Equal(SSE_CONTENT_TYPE, context.Response.ContentType);
+        }
+        
         #endregion
     }
 }