namespace XXX.Models.Authentication
{
    public class AuthenticationMiddleware
    {
        private readonly RequestDelegate _next;

        // Dependency Injection
        public AuthenticationMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            //Reading the AuthHeader which is signed with JWT
            string authHeader = context.Request.Headers["Authorization"];

            if (authHeader != null)
            {
                // Identity Principal
                var claims = new[]
                {
                    new Claim("name", "vadipok"),
                    new Claim(ClaimTypes.Role, "admin"),
                };
                var identity = new ClaimsIdentity(claims, "basic");
                context.User = new ClaimsPrincipal(identity);
            }
            //Pass to the next middlware
            await _next(context);
        }
    }
}

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            ............................................

            app.UseMiddleware<AuthenticationMiddleware>();

            ............................................
        }

        [Authorize(Roles = "admin")]
        public IActionResult Test()
        {
            ViewData["Message"] = "Test page.";

            return View();
        }

        private async Task Authenticate(User user)
        {
            // создаем один claim
            var claims = new List<Claim>
            {
                new Claim(ClaimsIdentity.DefaultNameClaimType, user.Email),
                new Claim(ClaimsIdentity.DefaultRoleClaimType, user.Role?.Name)
            };
            // создаем объект ClaimsIdentity
            ClaimsIdentity id = new ClaimsIdentity(claims, "ApplicationCookie", ClaimsIdentity.DefaultNameClaimType,
                ClaimsIdentity.DefaultRoleClaimType);
            // установка аутентификационных куки
            await HttpContext.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme, new ClaimsPrincipal(id));
        }

        [Authorize(Policy = "Admin")]
        public IActionResult Test()
        {
            ViewData["Message"] = "Test page.";

            return View();
        }

        [AllowAnonymous]
        public async Task<IActionResult> Login(string returnUrl)
        {
            var identity = ((ClaimsIdentity)HttpContext.User.Identity);

            var claims = new List<Claim>
            {
                new Claim("Authenticated", "True"),
                new Claim("tutututut", "True")
            };

            var claimsIdentity = new ClaimsIdentity(
                claims,
                identity.AuthenticationType,
                identity.NameClaimType,
                identity.RoleClaimType);

            await HttpContext.SignInAsync(
                CookieAuthenticationDefaults.AuthenticationScheme,
                new ClaimsPrincipal(claimsIdentity),
                new AuthenticationProperties());

            return Redirect(returnUrl);
        }

        [AllowAnonymous]
        public IActionResult AccessDenied(string returnUrl)
        {
            if (User.FindFirst("Authenticated") == null)
                return RedirectToAction("Login", new { returnUrl });

            return View();
        }

            services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
                .AddCookie(options =>
                {
                    options.LoginPath = "/Home/Login";
                    options.AccessDeniedPath = "/Home/AccessDenied";
                });

            services.AddAuthorization(options =>
            {
                options.AddPolicy("Authenticated", policy => policy.RequireClaim("Authenticated"));
                options.AddPolicy("Admin", policy => policy.RequireClaim("Admin"));
                options.AddPolicy("Admin123", policy => policy.RequireClaim("Admin123"));
            });