Program.cs

using System.Security.Claims;
using MESTSOFT.AuthorizationRequirements;
using MESTSOFT.Data;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Authorization;
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllersWithViews();
builder.Services.AddSession();
builder.Services.AddHttpContextAccessor();
builder.Services.AddRazorPages()
    .AddRazorRuntimeCompilation();
builder.Services.AddRecaptchaService();
builder.Services.AddDbContext<DataContext>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection"), p => p.UseQuerySplittingBehavior(QuerySplittingBehavior.SplitQuery)));
builder.Services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
.AddCookie(x =>
{
    x.Cookie.HttpOnly = true;
    x.ExpireTimeSpan = TimeSpan.FromMinutes(30);
    x.AccessDeniedPath = "/Home/AccessDenied/";
    x.LoginPath = "/Auth/Login/";
    x.LogoutPath = "/Auth/Logout/";
    x.SlidingExpiration = true;
});

builder.Services.AddAuthorization(config =>
{
    config.AddPolicy("Admin", policyBuilder =>
                policyBuilder.AddRequirements(new AdminClaim(ClaimTypes.Name)));
    config.AddPolicy("Gym", policyBuilder =>
                policyBuilder.AddRequirements(new GymClaim(ClaimTypes.Name)));
    config.AddPolicy("Customer", policyBuilder =>
                policyBuilder.AddRequirements(new CustomerClaim(ClaimTypes.Name)));
});

builder.Services.AddScoped<IAuthorizationHandler, AdminClaimHandler>();
builder.Services.AddScoped<IAuthorizationHandler, GymClaimHandler>();
builder.Services.AddScoped<IAuthorizationHandler, CustomerClaimHandler>();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
}
app.UseAuthentication();
app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();
app.UseSession();
app.UseCookiePolicy();
app.UseAuthorization();

app.MapControllerRoute(
    name: "area",
    pattern: "{area:exists}/{controller=Home}/{action=Index}/{id?}");
app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");
app.Run();