When exception thrown, CORS is lost - asp.net

Question

I am using ASP.NET Web API, after throwing exception, I am able to catch it in GlobalExceptionHandler, but I get CORS error and can't enter App_error. I tried multiple solutions, nothing is working, right now I have this flow.
Custom Exception is thrown in controller, then we enter GlobalExceptionHandler:
public class GlobalExceptionHandler : IExceptionHandler
{
public Task HandleAsync(ExceptionHandlerContext context, CancellationToken cancellationToken)
{
ExceptionDispatchInfo.Capture(context.Exception).Throw();
return Task.CompletedTask;
}
}
And it is not going further, I get CORS on front.
Any solution?

Answer 1

You could do something like this
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Http;
using System.Web.Http.ExceptionHandling;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Threading;
namespace Web.API.Handler
{
public class ErrorHandler : ExceptionHandler
{
public override void Handle(ExceptionHandlerContext context)
{
context.Result = new TextPlainErrorResult()
{
Request = context.ExceptionContext.Request,
Content = "Oops! Sorry! Something went wrong." + "Please contact support so we can try to fix it."
};
}
private class TextPlainErrorResult : IHttpActionResult
{
public HttpRequestMessage Request { get; set; }
public string Content { get; set; }
public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
{
HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.InternalServerError, Content);
//CORS Support
if (!response.Headers.Contains("Access-Control-Allow-Origin"))
response.Headers.Add("Access-Control-Allow-Origin", "*");
return Task.FromResult(response);
}
}
}
}

Answer 2

I managed to resolve problem by doing everything inside lifter, so App_error is not used anymore
public class GlobalExceptionHandler : IExceptionHandler
{
private readonly Logger m_Logger = LogManager.GetCurrentClassLogger();
public Task HandleAsync(ExceptionHandlerContext context, CancellationToken cancellationToken)
{
var exception = context.Exception;
var statusCode = HttpStatusCode.InternalServerError;
if (exception != null)
{
var errorMessage = exception.Message;
if (exception is BaseException be)
{
statusCode = be.StatusCode;
}
m_Logger.Error(exception, context.Request.RequestUri.AbsoluteUri);
var response = context.Request.CreateResponse(statusCode, new { errorMessage });
context.Result = new ResponseMessageResult(response);
}
return Task.CompletedTask;
}
}