public NoteDataService(IMvxFileStore mvxFileStorage)
{
filePath = "noteStorage.json";
converter = new MvxJsonConverter();
storage = mvxFileStorage;
if (!storage.Exists(filePath))
{
storage.WriteFile(filePath, converter.SerializeObject(Enumerable.Empty<Note>()));
}
}
/// <summary>
/// Check if a file exists on a certain location
/// </summary>
/// <param name="folder">The name of the folder</param>
/// <param name="fullName">The name of the file</param>
/// <returns>True if the file exists, otherwise false.</returns>
public override bool Exists(string folder, string fullName)
{
var fullPath = _fileStore.PathCombine(folder, fullName);
return(_fileStore.Exists(fullPath));
}
private async Task LoadDataService(IDataService dataService, bool overrideCache = false)
{
List <Item> currentItems = new List <Item>();
bool loadedFromCache = false;
if (fileStore != null)
{
string lastRefreshText;
if (fileStore.TryReadTextFile("LastRefresh-" + dataService.GetType().ToString(), out lastRefreshText))
{
var lastRefreshTime = DateTime.Parse(lastRefreshText);
var timeSinceLastRefreshInMinutes = (DateTime.Now - lastRefreshTime).TotalMinutes;
//has cache expired?
if (overrideCache || timeSinceLastRefreshInMinutes > AppSettings.CacheIntervalInMinutes)
{
currentItems = await dataService.GetItems();
}
else //load from cache
{
string cachedItemsText;
pool.WaitOne();
try
{
if (fileStore.TryReadTextFile("CachedItems-" + dataService.GetType().ToString(), out cachedItemsText))
{
currentItems = mvxJsonConverter.DeserializeObject <List <Item> >(cachedItemsText);
loadedFromCache = true;
}
}
catch
{
ServiceLocator.MessageService.ShowErrorAsync("Error Deserializing " + dataService.GetType().ToString(), "Error loading cache");
}
finally
{
pool.Release();
}
}
}
else
{
currentItems = await dataService.GetItems();
}
}
try
{
if (!loadedFromCache && currentItems.Count > 0)
{
if (fileStore.Exists("CachedItems-" + dataService.GetType().ToString()))
{
fileStore.DeleteFile("CachedItems-" + dataService.GetType().ToString());
}
if (fileStore.Exists("LastRefresh-" + dataService.GetType().ToString()))
{
fileStore.DeleteFile("LastRefresh-" + dataService.GetType().ToString());
}
fileStore.WriteFile("CachedItems-" + dataService.GetType().ToString(), mvxJsonConverter.SerializeObject(currentItems));
fileStore.WriteFile("LastRefresh-" + dataService.GetType().ToString(), DateTime.Now.ToString());
}
items.AddRange(currentItems);
}
catch
{
ServiceLocator.MessageService.ShowErrorAsync("Error retrieving items from " + dataService.GetType().ToString() + "\n\nPossible Causes:\nNo internet connection\nRemote Service unavailable", "Application Error");
}
}
