don't send multiple header keys to save space

Author: thefringeninja

src/SqlStreamStore.HAL.Tests/OptionsTests.cs

@@ -27,7 +27,7 @@ public static IEnumerable<object[]> OptionsAllowedMethodCases()
                 "/stream",
                 new[] { HttpMethod.Get, HttpMethod.Head, HttpMethod.Options }
             };
-            
+
             yield return new object[]
             {
                 "/stream/123",
@@ -45,7 +45,7 @@ public static IEnumerable<object[]> OptionsAllowedMethodCases()
                 "/streams/a-stream/0",
                 new[] { HttpMethod.Get, HttpMethod.Head, HttpMethod.Delete, HttpMethod.Options }
             };
-            
+
             yield return new object[]
             {
                 $"/streams/a-stream/{Guid.Empty}",
@@ -73,10 +73,19 @@ public async Task options_returns_the_correct_cors_headers(string requestUri, Ht
             {
                 response.StatusCode.ShouldBe(HttpStatusCode.OK);
                 response.Headers.GetValues(Constants.Headers.AccessControl.AllowHeaders)
-                    .ShouldBe(new[] { Constants.Headers.ContentType, Constants.Headers.XRequestedWith, Constants.Headers.Authorization }, true);
+                    .SelectMany(x => x.Split(','))
+                    .ShouldBe(new[]
+                        {
+                            Constants.Headers.ContentType,
+                            Constants.Headers.XRequestedWith,
+                            Constants.Headers.Authorization
+                        },
+                        true);
                 response.Headers.GetValues(Constants.Headers.AccessControl.AllowOrigin)
+                    .SelectMany(x => x.Split(','))
                     .ShouldBe(new[] { "*" }, true);
                 response.Headers.GetValues(Constants.Headers.AccessControl.AllowMethods)
+                    .SelectMany(x => x.Split(','))
                     .ShouldBe(allowedMethods.Select(_ => _.Method), true);
             }
         }

src/SqlStreamStore.HAL/ApplicationBuilderExtensions.cs

@@ -42,13 +42,13 @@ public static IApplicationBuilder UseAllowedMethods(this IApplicationBuilder bui
 
             Task Options(HttpContext context, Func<Task> next)
             {
-                context.Response.Headers.Append(
+                context.Response.Headers.AppendCommaSeparatedValues(
                     Constants.Headers.AccessControl.AllowMethods,
                     allowedMethodsHeaderValue);
-                context.Response.Headers.Append(
+                context.Response.Headers.AppendCommaSeparatedValues(
                     Constants.Headers.AccessControl.AllowHeaders,
                     allowedHeadersHeaderValue);
-                context.Response.Headers.Append(
+                context.Response.Headers.AppendCommaSeparatedValues(
                     Constants.Headers.AccessControl.AllowOrigin,
                     "*");
 

src/SqlStreamStore.HAL/HttpContextExtensions.cs

@@ -49,7 +49,7 @@ private static Task WriteNotModifiedResponse(HttpContext context, Response respo
             context.Response.StatusCode = 304;
             foreach(var header in s_NotModifiedRequiredHeaders.Where(response.Headers.Keys.Contains))
             {
-                context.Response.Headers.Append(header, response.Headers[header]);
+                context.Response.Headers.AppendCommaSeparatedValues(header, response.Headers[header]);
             }
 
             return Task.CompletedTask;
@@ -61,7 +61,7 @@ private static Task WriteResponseInternal(HttpContext context, Response response
 
             foreach(var header in response.Headers)
             {
-                context.Response.Headers.Append(header.Key, header.Value);
+                context.Response.Headers.AppendCommaSeparatedValues(header.Key, header.Value);
             }
 
             return response.WriteBody(context.Response, context.RequestAborted);