Caching asynchronous operations

Question

I am looking for an elegant way of caching the results of my asynchronous operations.

I first had a synchronous method like this:

public String GetSt         


        

Answer 1

It's actually reasonable (and depending on your design and performance, crucial) to keep those failed tasks as a Negative Cache. Otherwise, if a url always fails, using it again and again defeats the point of using a cache altogether.

What you do need is a way to clear the cache from time to time. The simplest way is to have a timer that replaces the ConcurrentDictionarry instance. The more robust solution is to build your own LruDictionary or something similar.