/// <summary>
/// Saves a collectionCacheIndex to cache
/// </summary>
/// <param name="config"></param>
/// <param name="lastModified"></param>
public static async Task save( IonConfig config, DateTime lastModified )
{
string collectionURL = PagesURLs.getCollectionURL( config );
CollectionCacheIndex cacheIndex = new CollectionCacheIndex( collectionURL, DateTimeUtils.now().ToUniversalTime(), lastModified );
await CacheIndexStore.save( collectionURL, cacheIndex, config ).ConfigureAwait( false );
}
/// <summary>
/// Gets a collection from the server
/// </summary>
/// <param name="collectionIdentifier"></param>
/// <returns></returns>
private async Task<IonCollection> getCollectionFromServerAsync( CollectionCacheIndex cacheIndex, bool cacheAsBackup )
{
//DateTime lastModified = cacheIndex != null ? cacheIndex.lastModified : DateTime.MinValue;
try
{
// Retrive collecion from server and parse it
HttpResponseMessage response = await _dataClient.getCollectionAsync( _config.collectionIdentifier, cacheIndex != null ? cacheIndex.lastModified : DateTime.MinValue ).ConfigureAwait( false );
// Only parse the answer if it is not newer than the cached version
if( !( response.StatusCode == System.Net.HttpStatusCode.NotModified ) )
{
// Parse collection
IonCollection collection = await DataParser.parseCollectionAsync( response ).ConfigureAwait( false );
// Add collection to memory cache
_memoryCache.collection = collection;
// Save collection to isolated storage
await StorageUtils.saveCollectionToIsolatedStorageAsync( collection, _config ).ConfigureAwait( false );
// save cacheIndex
await saveCollectionCacheIndexAsync( collection.last_changed ).ConfigureAwait( false );
return collection;
}
else
{
// Collection in the server is the same as stored already in isolated storage cache
if( _memoryCache.collection == null )
{
// Only load collection from isolated storage cache, if the memory cache has no collection cached
try
{
// Get collection from isolated storage
IonCollection collection = await StorageUtils.loadCollectionFromIsolatedStorageAsync( _config ).ConfigureAwait( false );
// Add collection to memory cache
if( collection != null )
{
_memoryCache.collection = collection;
}
// change the last-mofied date in the cacheIndex to now
await saveCollectionCacheIndexAsync( collection.last_changed ).ConfigureAwait( false );
return collection;
}
catch( Exception e )
{
IonLogging.log( "Error getting collection from isolated storage. Message: " + e.Message, IonLogMessageTypes.ERROR );
return null;
}
}
else
{
// change the last-mofied date in the cacheIndex to now
await saveCollectionCacheIndexAsync( _memoryCache.collection.last_changed ).ConfigureAwait( false );
return _memoryCache.collection;
}
}
}
catch( Exception e )
{
IonLogging.log( "Error retreiving collection data: " + e.Message, IonLogMessageTypes.ERROR );
return null;
}
}
/// <summary>
/// Gets a collection from the cache
/// </summary>
/// <param name="collectionIdentifier"></param>
/// <returns></returns>
private async Task<IonCollection> getCollectionFromCacheAsync( CollectionCacheIndex cacheIndex, bool serverCallAsBackup )
{
string collectionURL = PagesURLs.getCollectionURL( _config );
// retrieve from memory cache
IonCollection collection = _memoryCache.collection;
if( collection != null )
{
return collection;
}
// try to load collection from isolated storage
try
{
collection = await StorageUtils.loadCollectionFromIsolatedStorageAsync( _config ).ConfigureAwait( false );
// Add collection to memory cache
if( collection != null )
{
_memoryCache.collection = collection;
}
}
catch( Exception e )
{
IonLogging.log( "Error getting collection from isolated storage. Message: " + e.Message, IonLogMessageTypes.ERROR );
}
return collection;
}
/// <summary>
/// Saves a collectionCacheIndex to cache
/// </summary>
/// <param name="config"></param>
/// <param name="lastModified"></param>
public static async Task save(IonConfig config, DateTime lastModified)
{
string collectionURL = PagesURLs.getCollectionURL(config);
CollectionCacheIndex cacheIndex = new CollectionCacheIndex(collectionURL, DateTimeUtils.now().ToUniversalTime(), lastModified);
await CacheIndexStore.save(collectionURL, cacheIndex, config).ConfigureAwait(false);
}