RedirMiddleware.cs

namespace XXXCUSTOM.Middleware
{
    using Microsoft.AspNetCore.Http;
    using Sitecore.AspNet.RenderingEngine;
    using Sitecore.LayoutService.Client.Response.Model;
    using Sitecore.LayoutService.Client.Response.Model.Fields;
    using System.Threading.Tasks;

    public class RedirMiddleware
    {
        private const string RedirectTemplateID = "XXXX-XXXX-XXXX-XXX-XXXX";
        
        public RedirectMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task InvokeAsync(HttpContext context)
        {
            var custrequest = context.GetSitecoreRenderingContext();
            var custroute = custrequest.Response?.Content?.Sitecore?.Route;
            if (custroute == null)
            {
                await _next(context);
            }

            if (!IsRedirect(route, context))
            {
                await _next(context);
            }
        }

        private bool IsRedirect(Route route, HttpContext context)
        {
            //RUN Redirect LOGIC!!!
            if (route == null)
            {
                return false;
            }

            if (route.TemplateId != RedirectTemplateID)
            {
                return false;
            }

            var isPermanent = false;

            var redirectType = route.ReadField<ItemLinkField>("Response Status Code");

            if (redirectType != null)
            {
                if (redirectType.Url != null)
                {
                    if (redirectType.Url.Contains("301"))
                    {
                        isPermanent = true;
                    }
                }
            }

            var redirectTextField = route.ReadField<TextField>("Redirect To Url");

            if (!string.IsNullOrEmpty(redirectTextField.Value))
            {
                context.Response.Redirect(redirectTextField.Value, isPermanent);
                return true;
            }

            var destinationField = route.ReadField<ItemLinkField>("Redirect To Item");
            var destinationUrl = destinationField?.Url;

            if (!string.IsNullOrEmpty(destinationUrl))
            {
                context.Response.Redirect(destinationUrl, isPermanent);
                return true;
            }

            return false;
        }
    }
}