Task <StorageItemDownloadInfo?> IStorageCache.GetItemAsync(string path,
CancellationToken?cancellationToken = null)
{
if (_cache == null)
{
throw new Exception("Cache is not initialized");
}
var cacheEntry = CacheExtensions.Get <TRecord?>(_cache, NormalizePath(path));
return(Task.FromResult <StorageItemDownloadInfo?>(cacheEntry is null
? null
: new StorageItemDownloadInfo(cacheEntry.FileSize, cacheEntry.Date,
() => cacheEntry.OpenRead())));
}
async Task <StorageItemDownloadInfo?> IStorageCache.GetOrAddItemAsync(string path,
Func <Task <StorageItemDownloadInfo?> > addItem, CancellationToken?cancellationToken = null)
{
if (_cache == null)
{
throw new Exception("Cache is not initialized");
}
var key = NormalizePath(path);
if (!CacheExtensions.TryGetValue(_cache, key, out TRecord? cacheEntry)) // Look for cache key.
{
var itemLock = _locks.GetOrAdd(key, _ => new SemaphoreSlim(1, 1));
await itemLock.WaitAsync(cancellationToken ?? CancellationToken.None);
try
{
if (!CacheExtensions.TryGetValue(_cache, key, out cacheEntry))
{
var result = await addItem();
if (result == null)
{
Logger.LogDebug("File {File} not found", key);
return(null);
}
if (Options.MaxFileSizeToStore > 0 &&
result.FileSize > Options.MaxFileSizeToStore)
{
Logger.LogWarning(
"File {Key} exceed maximum cache file size. File size: {FleSize}. Maximum size: {MaximumSize}",
key, result.FileSize,
Helpers.HumanSize(Options.MaxFileSizeToStore));
return(result);
}
var stream = result.GetStream();
await using (stream)
{
Logger.LogDebug("Download file {Key}", key);
cacheEntry = await GetEntryAsync(result, stream, cancellationToken);
var options = new MemoryCacheEntryOptions {
SlidingExpiration = Options.Ttl
};
options.RegisterPostEvictionCallback((_, value, _, _) =>
{
if (value is TRecord deletedRecord)
{
DisposeItem(deletedRecord);
}
Logger.LogDebug("Remove file {ObjKey} from cache", key);
});
if (Options.MaxCacheSize > 0)
{
options.Size = result.FileSize;
}
Logger.LogDebug("Add file {Key} to cache", key);
_cache.Set(key, cacheEntry, options);
}
}
}
catch (Exception ex)
{
Logger.LogError(ex, "Error caching file {File}: {ErrorText}", key, ex.ToString());
return(null);
}
finally
{
itemLock.Release();
}
}
return(cacheEntry is null
? null
: new StorageItemDownloadInfo(/*cacheEntry.Metadata, */ cacheEntry.FileSize, cacheEntry.Date,
() => cacheEntry.OpenRead()));
}
