What is the role and purpose of functional interfaces in programming?

To implement caching in C# projects, I used several approaches and tools:

• MemoryCache from the System.Runtime.Caching namespace for in-memory data caching.
• Distributed cache (e.g., Redis) for caching in a distributed environment, useful for scaling.
• Using caching attributes in ASP.NET Core, such as [ResponseCache], for HTTP response caching.
• Implementing a custom cache layer using dictionaries and timeouts for specific tasks.

Example of using MemoryCache:

using System.Runtime.Caching;

MemoryCache cache = MemoryCache.Default;
string cacheKey = "user_123";
var userData = cache.Get(cacheKey);
if (userData == null)
{
    userData = GetUserFromDatabase(123); // method to get data
    cache.Set(cacheKey, userData, DateTimeOffset.Now.AddMinutes(10));
}
// Use userData

This approach helps reduce database load and improve application performance.