private async Task <SpotlightFeedReader> InitializeAsync_(IFeedCache <string> cache)
{
// DEBUGGING ONLY: a hardcoded delay to make sure the loading page is working correctly
//await Task.Run(() =>
//{
// Thread.Sleep(5000);
//});
// if the cache has not yet been initialized, initialize it
if (cache == null)
{
cache = await SpotlightFeedCacheFactory.CreateSpotlightFeedCache();
}
m_cache = cache;
SpotlightItemRoot root = null;
// try to load the feed from the web first
var json = await LoadJsonFromWeb_(m_url);
if (json != null)
{
// try to deserialize
root = await DeserializeJson_(json);
if (root == null)
{
// invalid json, clear it and try to fetch from cache
json = null;
}
else
{
// if there are web-based images, download them and re-serialize to json
json = await SerializeJsonWithLocalImages_(root);
// store the result back in cache; at this point we know we have valid json
await cache.PutFeedAsync(json);
}
}
// if we didn't get a valid feed from the web, try to fetch from cache
if (json == null)
{
json = cache.GetFeed();
if (json != null)
{
// try to deserialize
root = await DeserializeJson_(json);
if (root == null)
{
json = null;
}
}
}
m_root = root;
return(this);
}