Redis Caching

When your application grows beyond a single server, Redis is the gold standard for distributed caching. It’s fast, scalable, and accessible from anywhere—perfect for microservices, cloud deployments, and high-availability scenarios.

REN.Kit.CacheKit makes using Redis cache in your .NET 8 or .NET 9 projects not only straightforward, but enterprise-ready. You get high performance, reliability, and all the power of Redis, with a developer-friendly interface.

---

1. Configuration: Define Redis Settings in appsettings.json

Before using Redis, add the following configuration block to your appsettings.json:

"CacheConfiguration": {
  "RedisConfiguration": {
    "Url": "localhost:6379",
    "TimeConfiguration": {
      "AbsoluteExpirationInHours": 12
    },
    "DatabaseId": 4,
    "Username": "default",
    "Password": "ofqa9YpQ6iw5tmDsoH5EW1OTMJtKs2Gs",
    "AbortOnConnectFail": false,
    "IsAdmin":  false
  }
}

• Url: Address of your Redis server (can be remote or localhost)

• AbsoluteExpirationInHours: The max lifetime for a cache entry

• DatabaseId: Redis logical database (usually 0)

• Username/Password: For secured Redis clusters

• AbortOnConnectFail: Should connections be retried or fail fast

• IsAdmin: (Optional) Set to true if you want to allow administrative operations like FlushDb.

⚠️ Security Tip:

Only enable IsAdmin if your use case requires it—such as calling Clear() to flush all keys.

---

2. Service Registration

After configuring your Redis cache, register REN.Kit for Redis in your Program.cs:

builder.Services.AddRENCaching(RegisterRENCaching.CacheType.Redis);

You can now inject IRENCacheService into your classes and use Redis for high-performance, distributed caching.

Here’s how the core registration works under the hood:

public static void AddRENCaching(this IServiceCollection services, CacheType cacheType)
{
    switch (cacheType)
    {
        case CacheType.InMemory:
            AddInMemoryRENCache<RENInMemoryCacheService>(services);
            break;
        case CacheType.Redis:
            AddRedisRENCache<RENRedisCacheService>(services);
            break;
        default:
            throw new ArgumentOutOfRangeException(nameof(cacheType), cacheType, null);
    }
}

---

Why Choose Redis Cache?

• Scalable: Multiple app instances can share the same cache instantly.

• High Availability: Use with Redis Sentinel or clustering for failover.

• Lightning Fast: Network lookups in microseconds, with optional persistence.

• Perfect for:

  • Distributed session storage

  • User authentication tokens

  • Large data objects shared across services

  • Rate limiting, leaderboards, and more

Pro Tips:

• Use Redis when your application runs on more than one server, container, or instance.

• For cloud or Kubernetes deployments, Redis is almost always the right choice for distributed caching.

• Don’t forget: You can override or extend any REN.Kit cache service for custom logic!

Why is Clear() supported for Redis, but not for In-Memory?

Because Redis supports the FLUSHDB operation natively, while IMemoryCache does not support clearing all entries at once. In distributed environments, this allows you to quickly reset the cache for all connected app instances. Remember to enable "IsAdmin": true if you plan to use this feature.