Example of how to implement global error handling in WebApi

WebApi-Error-Middleware.cs

using System;
using FluentValidation;
using System.Text.Json;
using System.Threading.Tasks;
using Logic.Exceptions;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Hosting;
using System.Linq;
using System.Collections.Generic;
using Microsoft.Data.SqlClient;

namespace Api.Middleware
{
    public class ErrorHandlingMiddleware : IMiddleware
    {
        private readonly IWebHostEnvironment _env;
        const string RESPONSE_CONTENT_TYPE = "application/json";

        public ErrorHandlingMiddleware(IWebHostEnvironment env)
        {
            _env = env;
        }

        public async Task InvokeAsync(HttpContext context, RequestDelegate next)
        {
            try
            {
                await next(context);
            }
            catch (Exception ex)
            {
                await HandleExceptionAsync(context, ex);
            }
        }

        private async Task HandleExceptionAsync(HttpContext context, Exception exception)
        {
            IEnumerable<string> message = new List<string> { exception.Message }; ;
            int statusCode;
            var stackTrace = _env.IsDevelopment() ? exception.StackTrace : string.Empty;

            switch (exception)
            {
                case ValidationException:
                    {
                        var validationException = (ValidationException)exception;
                        message = validationException.Errors.Select(x => x.ErrorMessage);
                        statusCode = StatusCodes.Status400BadRequest;
                        break;
                    }
                case NotFoundException:
                    {
                        statusCode = StatusCodes.Status404NotFound;
                        break;
                    };
                case SqlException:
                    {
                        statusCode = StatusCodes.Status500InternalServerError;
                        break;
                    };
                default:
                    {
                        statusCode = StatusCodes.Status500InternalServerError;
                        break;
                    };
            }

            var result = JsonSerializer.Serialize(new { error = message, stackTrace });
            context.Response.ContentType = RESPONSE_CONTENT_TYPE;
            context.Response.StatusCode = statusCode;
            await context.Response.WriteAsync(result);
        }
    }
}