public async Task <object?> GetItem(IBlobCacheKey cacheKey, Type targetType)
{
var blobContainer = cacheKey.Container;
var key = cacheKey.Key;
// Attempt to read blob from the storage container
try
{
return(await _blobStorageService.GetDeserializedJson(cacheKey.Container, cacheKey.Key, targetType));
}
catch (JsonException e)
{
// If there's an error deserializing the blob, we should
// assume it's not salvageable and delete it so that it's re-built.
_logger.LogWarning(e, $"Error deserializing JSON for blobContainer {blobContainer} and cache " +
$"key {key} - deleting cached JSON");
await _blobStorageService.DeleteBlob(blobContainer, key);
}
catch (FileNotFoundException)
{
// Do nothing as the blob just doesn't exist
}
catch (Exception e)
{
_logger.LogError(e, "Caught error fetching cache entry from: {BlobContainer}/{Key}", blobContainer, key);
}
return(default);
public static Mock <IBlobCacheService> SetupGetItemForCacheMiss <TItem>(
this Mock <IBlobCacheService> cacheService,
IBlobCacheKey expectedCacheKey)
where TItem : class
{
cacheService.Setup(mock => mock.GetItem(
It.Is <IBlobCacheKey>(ck =>
ck.Key == expectedCacheKey.Key &&
ck.Container == expectedCacheKey.Container),
It.IsAny <Func <Task <TItem> > >()))
.Returns(async(
IBlobCacheKey _,
Func <Task <TItem> > entityProvider) => await entityProvider());
return(cacheService);
}
public async Task <Either <ActionResult, TItem> > GetItem <TItem>(
IBlobCacheKey cacheKey,
Func <Task <Either <ActionResult, TItem> > > itemSupplier)
where TItem : class
{
// Attempt to read blob from the cache container
var cachedEntity = await GetItem <TItem>(cacheKey);
if (cachedEntity != null)
{
return(cachedEntity);
}
// Cache miss - invoke provider instead
return(await itemSupplier().OnSuccessDo(async entity =>
{
// Write result to cache as a json blob before returning
await SetItem(cacheKey, entity);
}));
}
public async Task <TItem> GetItem <TItem>(
IBlobCacheKey cacheKey,
Func <Task <TItem> > itemSupplier)
where TItem : class
{
// Attempt to read blob from the cache container
var cachedEntity = await GetItem <TItem>(cacheKey);
if (cachedEntity != null)
{
return(cachedEntity);
}
// Cache miss - invoke provider instead
var entity = await itemSupplier();
// Write result to cache as a json blob before returning
await SetItem(cacheKey, entity);
return(entity);
}
public async Task DeleteCacheFolder(IBlobCacheKey cacheFolderKey)
{
await _blobStorageService.DeleteBlobs(cacheFolderKey.Container, cacheFolderKey.Key);
}
public async Task DeleteItem(IBlobCacheKey cacheKey)
{
await _blobStorageService.DeleteBlob(cacheKey.Container, cacheKey.Key);
}
public async Task <TItem?> GetItem <TItem>(IBlobCacheKey cacheKey)
where TItem : class
{
return((TItem?) await GetItem(cacheKey, typeof(TItem)));
}