public static IAsyncOperation<IEnumerable<object>> GetFeedsFromDBAsync()
{
return Task.Factory.StartNew(() =>
{
var v = new List<object>();
using (var db = GetUserDB())
{
var stmt = db.PrepareStatement("SELECT id, uri,title, image_uri FROM feeds");
while (stmt.HasMore())
{
int id = stmt.ColumnAsIntAt(0);
var fi = new FeedInfo(
stmt.ColumnAsTextAt(1),
stmt.ColumnAsTextAt(2),
stmt.ColumnAsTextAt(3));
fi.IsLoaded = true;
LoadFeedItemsFor(db, id, fi);
v.Add(fi);
}
return (IEnumerable<object>)v;
}
}).AsAsyncOperation();
}
public void Run(IBackgroundTaskInstance taskInstance)
{
//
// Associate a cancellation handler with the background task.
//
taskInstance.Canceled += OnCanceled;
if (!ViewModelHelper.IsConnected)
{
return;
}
//
// Get the deferral object from the task instance, and take a reference to the taskInstance.
//
_deferral = taskInstance.GetDeferral();
var uris = PersistenceHelper.GetUserFeedsAsync().AsTask().Result;
var feeds = new List<FeedInfo>();
foreach (var uri in uris)
{
try
{
var fi = new FeedInfo(uri);
fi.LoadNonGUI();
feeds.Add(fi);
}
catch
{
Debug.WriteLine("Failed to load FeedInfo");
}
}
PersistenceHelper.SaveFeedsToDBAsync(feeds).AsTask().Wait();
_deferral.Complete();
}
public void LoadFeedsFromTheInternet()
{
_feeds = new ObservableVector<object>();
PersistenceHelper.GetUserFeedsAsync().AsTask().ContinueWith(t =>
{
foreach (var uri in t.Result)
{
try
{
var fi = new FeedInfo(uri);
fi.BeginLoad();
_feeds.Add(fi);
}
catch
{
Debug.WriteLine("Failed to load FeedInfo");
}
}
if (_feeds.Count > 0)
{
SelectedFeed = (FeedInfo)_feeds[0];
}
});
}
private static void SaveFeedToDB(Database db, FeedInfo feed)
{
var stmt = db.PrepareStatement("INSERT INTO feeds (uri, title, image_uri) values (?,?,?)");
stmt.BindText(1, feed.Uri.AbsoluteUri);
stmt.BindText(2, feed.Title);
if (feed.ImageUri != null)
{
stmt.BindText(3, feed.ImageUri.AbsoluteUri);
}
stmt.Execute();
stmt = db.PrepareStatement("SELECT last_insert_rowid()");
int feedId = 0;
if (stmt.HasMore())
{
feedId = stmt.ColumnAsIntAt(0);
}
else
{
throw new Exception("Last inserted row id was not found in sqlite");
}
foreach (var feedItem in feed.FeedItems)
{
var fi = (FeedItem)feedItem;
if (fi.FullTextLoaded)
{
SaveFeedItemToDB(db, feedId, fi);
}
}
}
private static void LoadFeedItemsFor(Database db, int feedId, FeedInfo feedInfo)
{
var stmt = db.PrepareStatement("SELECT title, summary, uri, image_uri, text FROM feed_items where feed_id = ?");
stmt.BindInt(1, feedId);
while (stmt.HasMore())
{
FeedItem fi = new FeedItem(
stmt.ColumnAsTextAt(0),
stmt.ColumnAsTextAt(1),
stmt.ColumnAsTextAt(2),
stmt.ColumnAsTextAt(3),
stmt.ColumnAsTextAt(4));
feedInfo.FeedItems.Add(fi);
}
}