How do you implement caching?

Question

Accepted Answer

**IMemoryCache** — in-memory caching.

**Setup:**
```csharp
builder.Services.AddMemoryCache();
```

**Usage:**
```csharp
public class ProductService(IMemoryCache cache)
{
    public async Task<Product> GetProductAsync(int id)
    {
        var key = $"product_{id}";
        if (!cache.TryGetValue(key, out Product product))
        {
            product = await _db.Products.FindAsync(id);
            var options = new MemoryCacheEntryOptions()
                .SetAbsoluteExpiration(TimeSpan.FromMinutes(5));
            cache.Set(key, product, options);
        }
        return product;
    }
}
```

**Distributed cache:**
```csharp
builder.Services.AddStackExchangeRedisCache(options =>
{
    options.Configuration = "localhost:6379";
});
```

**Key:** MemoryCache for local, Redis for distributed.

C#: How do you implement caching?