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

Another easy way to do this is to extend Lazy to be AsyncLazy, like so:

public class AsyncLazy : Lazy>
{
    public AsyncLazy(Func> taskFactory, LazyThreadSafetyMode mode) :
        base(() => Task.Factory.StartNew(() => taskFactory()).Unwrap(), mode)
    { }

    public TaskAwaiter GetAwaiter() { return Value.GetAwaiter(); }
}

Then you can do this:

private readonly ConcurrentDictionary> _cache
    = new ConcurrentDictionary>();

public async Task GetStuffAsync(string url)
{
    return await _cache.GetOrAdd(url,
        new AsyncLazy(
            () => GetStuffInternalAsync(url),
            LazyThreadSafetyMode.ExecutionAndPublication));
}