Refactored

src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionFilter.cs

@@ -65,8 +65,10 @@ namespace Volo.Abp.AspNetCore.Mvc.ExceptionHandling
 
         protected virtual void HandleAndWrapException(ExceptionContext context)
         {
-            context.HttpContext.Response.StatusCode = (int)_statusCodeFinder.GetStatusCode(context.HttpContext, context.Exception);
+            context.HttpContext.Response.Headers.Add(AbpHttpConsts.AbpErrorFormat, "true");
-            context.HttpContext.Response.Headers.Add(new KeyValuePair<string, StringValues>("_AbpErrorFormat", "true"));
+
+            context.HttpContext.Response.StatusCode = 
+                (int)_statusCodeFinder.GetStatusCode(context.HttpContext, context.Exception);
 
             context.Result = new ObjectResult(
                 new RemoteServiceErrorResponse(

src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionHandlingMiddleware.cs

@@ -66,7 +66,7 @@ namespace Volo.Abp.AspNetCore.Mvc.ExceptionHandling
             httpContext.Response.Clear();
             httpContext.Response.StatusCode = (int)statusCodeFinder.GetStatusCode(httpContext, exception);
             httpContext.Response.OnStarting(_clearCacheHeadersDelegate, httpContext.Response);
-            httpContext.Response.Headers.Add(new KeyValuePair<string, StringValues>("_AbpErrorFormat", "true"));  //TODO: Constant
+            httpContext.Response.Headers.Add(AbpHttpConsts.AbpErrorFormat, "true");
 
             await httpContext.Response.WriteAsync(
                 jsonSerializer.Serialize(

src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/DynamicProxying/DynamicHttpProxyInterceptor.cs

@@ -209,7 +209,7 @@ namespace Volo.Abp.Http.Client.DynamicProxying
 
         private async Task ThrowExceptionForResponseAsync(HttpResponseMessage response)
         {
-            if (response.Headers.Contains("_AbpErrorFormat"))
+            if (response.Headers.Contains(AbpHttpConsts.AbpErrorFormat))
             {
                 var errorResponse = _jsonSerializer.Deserialize<RemoteServiceErrorResponse>(
                     await response.Content.ReadAsStringAsync()

src/Volo.Abp.Http/Volo/Abp/Http/AbpHttpConsts.cs

@@ -0,0 +1,7 @@
+namespace Volo.Abp.Http
+{
+    public static class AbpHttpConsts
+    {
+        public const string AbpErrorFormat = "_AbpErrorFormat";
+    }
+}

test/Volo.Abp.AspNetCore.Mvc.Tests/Volo/Abp/AspNetCore/Mvc/Uow/UnitOfWorkMiddleware_Exception_Rollback_Tests.cs

@@ -24,7 +24,7 @@ namespace Volo.Abp.AspNetCore.Mvc.Uow
         {
             var response = await GetResponseAsync("/api/unitofwork-test/ExceptionOnComplete", HttpStatusCode.InternalServerError);
 
-            response.Headers.GetValues("_AbpErrorFormat").FirstOrDefault().ShouldBe("true");
+            response.Headers.GetValues(AbpHttpConsts.AbpErrorFormat).FirstOrDefault().ShouldBe("true");
 
             var resultAsString = await response.Content.ReadAsStringAsync();