Question

For example, I have some repositories to grab some data I need:

Addressrepository.GetAddress(string para1, string para2)

UserRepository.GetUserDetail(string userName)

FinancialRepository.GetFinancialInfo(int userId)

To apply a cache aside pattern, I would like to do this:

base on parameters passing in and some identifier for each repository, construct a key.
Check Memory cache(or redis cache if we do down that route).
If info can't be found or expired, call the repository function to grab data and put into cache.

Ideally I would like to write a generic helper class to do this for all data loading functions.Something like the cache aside pattern described here: https://blog.cdemi.io/design-patterns-cache-aside-pattern/

However, in my case, I need to pass different parameters to different methods. In this case, is it possible to use Func and pass different parameters?

I checked msdn about this:

Func<T1, T2, T3, T4, T5, T6, T7, T8, TResult> Delegate

But how do I pass different type parameter and different number of parameters?

Answer 1

The easiest way is by not passing the parameters in at all and instead doing variable capture.

public T GetOrAdd<T>(string key, Func<T> builder)
{
    var result = _someCache.Get<T>(key);
    if(result != null)
       return result;

    result = builder();
    _someCache.Add(key, result);
    return result;
}

used like

var address = myCache.GetOrAdd<Address>(AddressKeyBuilder(para1, para2), 
                                        () => Addressrepository.GetAddress(para1, para2)
                                       );

This is the same pattern ConcurrentDictionary uses for it's GetOrAdd method.

What is a good way to implement cache aside pattern?

1 个答案: