Program.cs

using System.Text;
using System.Text.Json.Serialization;
using CollabDocs.Api.Hubs;
using CollabDocs.Infrastructure.Database;
using CollabDocs.Services;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.EntityFrameworkCore;
using Microsoft.IdentityModel.Tokens;
using StackExchange.Redis;
using Serilog;
using Prometheus;
using System.Threading.RateLimiting;

Log.Logger = new LoggerConfiguration()
    .WriteTo.Console()
    .CreateBootstrapLogger();

var builder = WebApplication.CreateBuilder(args);

builder.Host.UseSerilog((context, services, configuration) => configuration
    .ReadFrom.Configuration(context.Configuration)
    .ReadFrom.Services(services)
    .Enrich.FromLogContext()
    .WriteTo.Console());

// Add services to the container.
var redisConnectionString = builder.Configuration.GetConnectionString("RedisConnection") ?? "localhost:6379";
builder.Services.AddSingleton<IConnectionMultiplexer>(sp => ConnectionMultiplexer.Connect(redisConnectionString));
builder.Services.AddMemoryCache();
// Learn more about configuring OpenAPI at https://aka.ms/aspnet/openapi
builder.Services.AddControllers().AddJsonOptions(options => 
{
    options.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles;
});
builder.Services.AddScoped<AuthService>();
builder.Services.AddScoped<JwtService>();
builder.Services.AddScoped<PermissionService>();
builder.Services.AddScoped<DocumentService>();
builder.Services.AddSingleton<CollabDocs.Services.DocumentEditQueue>();
builder.Services.AddHostedService<CollabDocs.Infrastructure.BackgroundServices.EditProcessingService>();
builder.Services.AddHostedService<CollabDocs.Infrastructure.Redis.RedisCacheInvalidator>();

builder.Services.AddRateLimiter(options =>
{
    options.GlobalLimiter = PartitionedRateLimiter.Create<HttpContext, string>(httpContext =>
        RateLimitPartition.GetFixedWindowLimiter(
            partitionKey: httpContext.User.Identity?.Name ?? httpContext.Request.Headers.Host.ToString() ?? "anon",
            factory: partition => new FixedWindowRateLimiterOptions
            {
                AutoReplenishment = true,
                PermitLimit = 100,
                QueueLimit = 0,
                Window = TimeSpan.FromMinutes(1)
            }));
    options.RejectionStatusCode = 429;
});

builder.Services.AddHealthChecks().ForwardToPrometheus();
builder.Services.AddOpenApi();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseNpgsql(
        builder.Configuration.GetConnectionString("DefaultConnection")));
builder.Services.AddAuthentication(options =>
{
    options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultScheme = JwtBearerDefaults.AuthenticationScheme;
}).AddJwtBearer(options =>
{
    var jwtSection = builder.Configuration.GetSection("Jwt");
    var key = jwtSection["Key"]!;
    
    options.RequireHttpsMetadata = false;
    options.SaveToken = true;
    options.TokenValidationParameters = new TokenValidationParameters
    {
        ValidIssuer = jwtSection["Issuer"],
        ValidAudience = jwtSection["Audience"],
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(key)),
        ValidateIssuer = true,
        ValidateAudience = true,
        ValidateLifetime = true,
        ValidateIssuerSigningKey = true
    };
});
builder.Services.AddAuthorization();
builder.Services.AddSignalR().AddStackExchangeRedis(redisConnectionString);

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.MapHub<DocumentHub>("/hubs/document");

app.UseSerilogRequestLogging();
app.UseRateLimiter();

app.UseAuthentication();
app.UseAuthorization();

app.UseMetricServer();
app.UseHttpMetrics();

app.MapHealthChecks("/health");
app.UseHttpsRedirection();
app.MapControllers();
app.Run();