Ex2 (integrado): decorator de cache para IWorkshopRepository + TTL por Options

Controllers/DiDemoController.cs

@@ -0,0 +1,59 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using CampusWorkshops.Api.Services;
+
+namespace CampusWorkshops.Api.Controllers;
+
+[ApiController]
+[AllowAnonymous] // Deixe aberto para facilitar o teste
+[Route("api/[controller]")]
+public class DiDemoController : ControllerBase
+{
+    // Visualiza os IDs por lifetime
+    [HttpGet("lifetimes")]
+    public IActionResult Lifetimes(
+        [FromServices] IRequestIdTransient t1,
+        [FromServices] IRequestIdTransient t2,
+        [FromServices] IRequestIdScoped    s1,
+        [FromServices] IRequestIdScoped    s2,
+        [FromServices] IRequestIdSingleton g1,
+        [FromServices] IRequestIdSingleton g2)
+    {
+        return Ok(new {
+            transient1 = t1.Id, transient2 = t2.Id,    // normalmente diferentes NA MESMA chamada
+            scoped1 = s1.Id, scoped2 = s2.Id,          // iguais NA MESMA chamada; mudam entre chamadas
+            singleton1 = g1.Id, singleton2 = g2.Id     // sempre iguais
+        });
+    }
+
+    // Demonstra o "cativeiro" do transient dentro de um singleton
+    [HttpGet("captive-transient")]
+    public IActionResult Captive(
+        [FromServices] ReportingSingleton singleton,
+        [FromServices] IPerRequestClock clockTransient)
+    {
+        // clockTransient é Transient: CreatedAt muda entre requisições
+        var transientCreatedAtNow = clockTransient.CreatedAt;
+
+        // GetClockCreatedAt (TODO) deveria retornar o CreatedAt visto pelo singleton
+        DateTimeOffset? singletonClockCreatedAt = null;
+        string? error = null;
+        try
+        {
+            singletonClockCreatedAt = singleton.GetClockCreatedAt();
+        }
+        catch (Exception ex)
+        {
+            error = $"{ex.GetType().Name}: {ex.Message}";
+        }
+
+        return Ok(new {
+            transientCreatedAtNow,
+            singletonClockCreatedAt,
+            esperado = "Valores DIFERENTES por requisição",
+            observacao = "Mas como o transient foi resolvido DENTRO do singleton, ele congelou e não muda",
+            todoImplementado = error is null,
+            errorAoChamarSingleton = error
+        });
+    }
+}

Program.cs

@@ -8,6 +8,9 @@ using System.Text;
 using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.IdentityModel.Tokens;
 using Microsoft.OpenApi.Models;
+using CampusWorkshops.Api.Services;
+using Microsoft.Extensions.Options;
+using Microsoft.Extensions.Caching.Memory;
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -44,7 +47,32 @@ builder.Services.AddAuthorization(options =>
 builder.Services.AddDbContext<WorkshopsDbContext>(options =>
     options.UseSqlite(builder.Configuration.GetConnectionString("WorkshopsDb")));
 
-builder.Services.AddScoped<IWorkshopRepository, EfWorkshopRepository>();
+builder.Services.AddMemoryCache();
+builder.Services.Configure<CacheSettings>(builder.Configuration.GetSection("Cache"));
+
+
+// Primeiro registramos a implementação EF concreta
+builder.Services.AddScoped<EfWorkshopRepository>();
+
+// Depois expomos IWorkshopRepository como o "EF envelopado por cache"
+builder.Services.AddScoped<IWorkshopRepository>(sp =>
+    new CachedWorkshopRepository(
+        sp.GetRequiredService<EfWorkshopRepository>(),
+        sp.GetRequiredService<IMemoryCache>(),
+        sp.GetRequiredService<IOptionsSnapshot<CacheSettings>>()));
+
+// Lifetimes de exemplo
+builder.Services.AddTransient<IRequestIdTransient, RequestIdTransient>();
+builder.Services.AddScoped<IRequestIdScoped, RequestIdScoped>();
+builder.Services.AddSingleton<IRequestIdSingleton, RequestIdSingleton>();
+
+// Exemplo de "captive dependency"
+builder.Services.AddTransient<IPerRequestClock, PerRequestClock>(); // Transient
+builder.Services.AddSingleton<ReportingSingleton>();
+
+
+// Removendo para ativar o cached repository
+// builder.Services.AddScoped<IWorkshopRepository, EfWorkshopRepository>();
 builder.Services.AddControllers();
 builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen(o =>

Repositories/CachedWorkshopRepository.cs

@@ -0,0 +1,82 @@
+using CampusWorkshops.Api.Models;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Options;
+
+namespace CampusWorkshops.Api.Repositories;
+
+public sealed class CachedWorkshopRepository : IWorkshopRepository
+{
+    private readonly IWorkshopRepository _inner;
+    private readonly IMemoryCache _cache;
+    private readonly TimeSpan _ttl;
+
+    public CachedWorkshopRepository(
+        IWorkshopRepository inner,
+        IMemoryCache cache,
+        IOptionsSnapshot<CampusWorkshops.Api.Services.CacheSettings> opts)
+    {
+        _inner = inner;
+        _cache = cache;
+        _ttl = TimeSpan.FromSeconds(opts.Value.DefaultTtlSeconds);
+    }
+
+    private static string KeyById(Guid id) => $"workshops:byId:{id}";
+    private static string KeyList(DateTimeOffset? from, DateTimeOffset? to, string? q)
+        => $"workshops:list:{from?.ToUnixTimeSeconds()}:{to?.ToUnixTimeSeconds()}:{q?.Trim().ToLowerInvariant()}";
+    public async Task<IReadOnlyList<Workshop>> GetAllAsync(
+        DateTimeOffset? from, DateTimeOffset? to, string? q, CancellationToken ct)
+    {   
+        // Implementação final
+        var key = KeyList(from, to, q);
+        if (_cache.TryGetValue(key, out IReadOnlyList<Workshop>? cached) && cached is not null)
+            return cached;
+
+        var data = await _inner.GetAllAsync(from, to, q, ct);
+        _cache.Set(key, data, _ttl);
+        return data;
+    }
+
+
+    public async Task<Workshop?> GetByIdAsync(Guid id, CancellationToken ct)
+    {
+        var key = KeyById(id);
+        if (_cache.TryGetValue(key, out Workshop? cached) && cached is not null)
+            return cached;
+
+        var w = await _inner.GetByIdAsync(id, ct);
+        if (w is not null) _cache.Set(key, w, _ttl);
+        return w;
+    }
+
+    // Ações de escrita: apenas encaminham e limpam entradas simples
+    public async Task<Workshop> AddAsync(Workshop workshop, CancellationToken ct)
+    {
+        var w = await _inner.AddAsync(workshop, ct);
+        _cache.Remove(KeyById(w.Id));
+        return w;
+    }
+
+    public async Task<Workshop?> UpdateAsync(Workshop workshop, CancellationToken ct)
+    {
+        var w = await _inner.UpdateAsync(workshop, ct);
+        if (w is not null) _cache.Remove(KeyById(w.Id));
+        return w;
+    }
+
+    public async Task<bool> DeleteAsync(Guid id, CancellationToken ct)
+    {
+        var ok = await _inner.DeleteAsync(id, ct);
+        if (ok) _cache.Remove(KeyById(id));
+        return ok;
+    }
+
+    public Task<bool> ExistsAsync(Guid id, CancellationToken ct)
+        => _inner.ExistsAsync(id, ct);
+
+    public async Task<Workshop?> UpdatePartialAsync(Guid id, Action<Workshop> updateAction, CancellationToken ct)
+    {
+        var w = await _inner.UpdatePartialAsync(id, updateAction, ct);
+        if (w is not null) _cache.Remove(KeyById(w.Id));
+        return w;
+    }
+}

Services/CacheSettings.cs

@@ -0,0 +1,6 @@
+namespace CampusWorkshops.Api.Services;
+
+public sealed class CacheSettings
+{
+    public int DefaultTtlSeconds { get; set; } = 15;
+}

Services/PerRequestClock.cs

@@ -0,0 +1,12 @@
+namespace CampusWorkshops.Api.Services;
+
+public interface IPerRequestClock
+{
+    // Carimbo criado no CONSTRUTOR (não muda depois)
+    DateTimeOffset CreatedAt { get; }
+}
+
+public sealed class PerRequestClock : IPerRequestClock
+{
+    public DateTimeOffset CreatedAt { get; } = DateTimeOffset.UtcNow;
+}

Services/ReportingSingleton.cs

@@ -0,0 +1,23 @@
+using System;
+
+namespace CampusWorkshops.Api.Services;
+
+/// <summary>
+/// Singleton que recebe um Transient (IPerRequestClock).
+/// Na prática, o Transient é resolvido uma única vez, na construção do Singleton,
+/// e "vira" efetivamente singleton dentro dele.
+/// </summary>
+public sealed class ReportingSingleton
+{
+    private readonly IPerRequestClock _clock;
+
+    public ReportingSingleton(IPerRequestClock clock)
+    {
+        _clock = clock;
+    }
+
+    public DateTimeOffset GetClockCreatedAt()
+    {
+        return _clock.CreatedAt;
+    }
+}

Services/RequestId.cs

@@ -0,0 +1,9 @@
+namespace CampusWorkshops.Api.Services;
+
+public interface IRequestIdTransient { Guid Id { get; } }
+public interface IRequestIdScoped    { Guid Id { get; } }
+public interface IRequestIdSingleton { Guid Id { get; } }
+
+internal sealed class RequestIdTransient : IRequestIdTransient { public Guid Id { get; } = Guid.NewGuid(); }
+internal sealed class RequestIdScoped    : IRequestIdScoped    { public Guid Id { get; } = Guid.NewGuid(); }
+internal sealed class RequestIdSingleton : IRequestIdSingleton { public Guid Id { get; } = Guid.NewGuid(); }

appsettings.json

@@ -8,7 +8,8 @@
   "Jwt": {
     "Issuer": "CampusWorkshops",
     "Audience": "CampusWorkshops.Api",
-    "Key": "some-key"
+    "Key": "some-key-that-is-super-secret-always-secured"
   },
+  "Cache": { "DefaultTtlSeconds": 15 },
   "AllowedHosts": "*"
 }