A simple solution would be to use SemaphoreSlim.WaitAsync()
instead of a lock, and then you could get around the issue of awaiting inside a lock. Although, all other methods of MemoryCache
are thread-safe.
private SemaphoreSlim semaphoreSlim = new SemaphoreSlim(1);
public async Task<T> GetAsync(
string key, Func<Task<T>> populator, TimeSpan expire, object parameters)
{
if (parameters != null)
key += JsonConvert.SerializeObject(parameters);
if (!_cache.Contains(key))
{
await semaphoreSlim.WaitAsync();
try
{
if (!_cache.Contains(key))
{
var data = await populator();
_cache.Add(key, data, DateTimeOffset.Now.Add(expire));
}
}
finally
{
semaphoreSlim.Release();
}
}
return (T)_cache.Get(key);
}