member_center/src/MemberCenter.Web/Program.cs

using System.Security.Claims;
using System.Threading.RateLimiting;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.DataProtection;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.RateLimiting;
using MemberCenter.Application.Abstractions;
using MemberCenter.Application.Constants;
using MemberCenter.Infrastructure.Configuration;
using MemberCenter.Infrastructure.Identity;
using MemberCenter.Infrastructure.Persistence;
using MemberCenter.Infrastructure.Services;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;

EnvLoader.LoadDotEnvIfDevelopment();

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddDataProtection()
    .SetApplicationName("MemberCenter");

builder.Services.AddDbContext<MemberCenterDbContext>(options =>
{
    var connectionString = builder.Configuration.GetConnectionString("Default")
        ?? Environment.GetEnvironmentVariable("ConnectionStrings__Default")
        ?? "Host=localhost;Database=member_center;Username=postgres;Password=postgres";

    options.UseNpgsql(connectionString);
    options.UseOpenIddict();
});

builder.Services
    .AddIdentity<ApplicationUser, ApplicationRole>(options =>
    {
        options.User.RequireUniqueEmail = true;
        options.Password.RequireDigit = true;
        options.Password.RequireLowercase = true;
        options.Password.RequireUppercase = true;
        options.Password.RequireNonAlphanumeric = false;
        options.Password.RequiredLength = 8;
        options.Lockout.AllowedForNewUsers = true;
        options.Lockout.MaxFailedAccessAttempts = 5;
        options.Lockout.DefaultLockoutTimeSpan = TimeSpan.FromMinutes(15);
    })
    .AddEntityFrameworkStores<MemberCenterDbContext>()
    .AddDefaultTokenProviders();

builder.Services.Configure<SecurityStampValidatorOptions>(options =>
{
    options.ValidationInterval = TimeSpan.Zero;
});

var googleClientId = builder.Configuration["Authentication:Google:ClientId"]
    ?? Environment.GetEnvironmentVariable("Authentication__Google__ClientId");
var googleClientSecret = builder.Configuration["Authentication:Google:ClientSecret"]
    ?? Environment.GetEnvironmentVariable("Authentication__Google__ClientSecret");

var authenticationBuilder = builder.Services.AddAuthentication();
if (!string.IsNullOrWhiteSpace(googleClientId) && !string.IsNullOrWhiteSpace(googleClientSecret))
{
    authenticationBuilder.AddGoogle(options =>
    {
        options.ClientId = googleClientId;
        options.ClientSecret = googleClientSecret;
    });
}

builder.Services.ConfigureApplicationCookie(options =>
{
    options.LoginPath = "/account/login";
    options.Events = new CookieAuthenticationEvents
    {
        OnRedirectToLogin = context => HandleAdminAuthRedirectAsync(context),
        OnRedirectToAccessDenied = context => HandleAdminAuthRedirectAsync(context),
        OnValidatePrincipal = context => ValidatePrincipalAsync(context)
    };
});

builder.Services.AddAuthorization(options =>
{
    options.AddPolicy("Admin", policy => policy.RequireRole("admin", "superuser"));
    options.AddPolicy("Superuser", policy => policy.RequireRole("superuser"));
});

builder.Services.AddRateLimiter(options =>
{
    options.RejectionStatusCode = StatusCodes.Status429TooManyRequests;
    options.OnRejected = static async (context, token) =>
    {
        if (context.Lease.TryGetMetadata(MetadataName.RetryAfter, out var retryAfter))
        {
            context.HttpContext.Response.Headers.RetryAfter = Math.Ceiling(retryAfter.TotalSeconds).ToString();
        }

        await context.HttpContext.Response.WriteAsync("Too many requests.", token);
    };

    options.AddPolicy(RateLimitPolicyNames.PublicAuthLogin, context =>
        CreateFixedWindowLimiter(context, "web-auth-login", permitLimit: 10, TimeSpan.FromMinutes(5)));

    options.AddPolicy(RateLimitPolicyNames.PublicAuthRegister, context =>
        CreateFixedWindowLimiter(context, "web-auth-register", permitLimit: 5, TimeSpan.FromMinutes(15)));

    options.AddPolicy(RateLimitPolicyNames.PublicAuthRecovery, context =>
        CreateFixedWindowLimiter(context, "web-auth-recovery", permitLimit: 5, TimeSpan.FromMinutes(15)));
});

builder.Services.AddScoped<INewsletterService, NewsletterService>();
builder.Services.AddScoped<IEmailBlacklistService, EmailBlacklistService>();
builder.Services.AddScoped<ITenantService, TenantService>();
builder.Services.AddScoped<INewsletterListService, NewsletterListService>();
builder.Services.AddScoped<IAuditLogService, AuditLogService>();
builder.Services.AddScoped<IAuditLogWriter, AuditLogWriter>();
builder.Services.AddScoped<IAccountGovernanceService, AccountGovernanceService>();
builder.Services.AddScoped<IAccountEmailTemplateService, AccountEmailTemplateService>();
builder.Services.AddScoped<IEmailSender, SmtpEmailSender>();
builder.Services.AddScoped<IAccountEmailService, AccountEmailService>();
builder.Services.AddScoped<ISecuritySettingsService, SecuritySettingsService>();
builder.Services.AddScoped<ISubscriptionAdminService, SubscriptionAdminService>();
builder.Services.AddScoped<IAccountProvisioningService, AccountProvisioningService>();
builder.Services.AddScoped<IProfileService, ProfileService>();
builder.Services.Configure<SendEngineWebhookOptions>(builder.Configuration.GetSection("SendEngine"));
builder.Services.AddHttpClient<SendEngineWebhookPublisher>();
builder.Services.AddScoped<ISendEngineWebhookPublisher, SendEngineWebhookPublisher>();

builder.Services.AddOpenIddict()
    .AddCore(options =>
    {
        options.UseEntityFrameworkCore()
            .UseDbContext<MemberCenterDbContext>();
    });

builder.Services.AddControllersWithViews();
builder.Services.AddHttpContextAccessor();

var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    app.UseHsts();
}

app.UseRouting();
app.UseRateLimiter();
app.UseAuthentication();
app.UseAuthorization();

app.MapControllerRoute(
    name: "admin",
    pattern: "admin/{controller=Home}/{action=Index}/{id?}",
    defaults: new { area = "Admin" });

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

app.Run();

static Task HandleAdminAuthRedirectAsync(RedirectContext<CookieAuthenticationOptions> context)
{
    if (context.Request.Path.StartsWithSegments("/admin", StringComparison.OrdinalIgnoreCase))
    {
        context.Response.StatusCode = StatusCodes.Status404NotFound;
        return Task.CompletedTask;
    }

    context.Response.Redirect(context.RedirectUri);
    return Task.CompletedTask;
}

static async Task ValidatePrincipalAsync(CookieValidatePrincipalContext context)
{
    var userId = context.Principal?.FindFirstValue(ClaimTypes.NameIdentifier);
    if (!Guid.TryParse(userId, out var parsedUserId))
    {
        return;
    }

    var userManager = context.HttpContext.RequestServices.GetRequiredService<UserManager<ApplicationUser>>();
    var user = await userManager.FindByIdAsync(parsedUserId.ToString());
    if (user is null || user.DisabledAt.HasValue)
    {
        context.RejectPrincipal();
        await context.HttpContext.SignOutAsync();
    }
}

static RateLimitPartition<string> CreateFixedWindowLimiter(
    HttpContext context,
    string policyPrefix,
    int permitLimit,
    TimeSpan window)
{
    var identifier = context.User.Identity?.IsAuthenticated == true
        ? context.User.FindFirstValue(ClaimTypes.NameIdentifier)
            ?? context.User.Identity?.Name
            ?? context.Connection.RemoteIpAddress?.ToString()
            ?? "unknown"
        : context.Connection.RemoteIpAddress?.ToString() ?? "unknown";

    var partitionKey = $"{policyPrefix}:{identifier}";
    return RateLimitPartition.GetFixedWindowLimiter(partitionKey, _ => new FixedWindowRateLimiterOptions
    {
        PermitLimit = permitLimit,
        Window = window,
        QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
        QueueLimit = 0,
        AutoReplenishment = true
    });
}