/// <summary>
/// Query popular topics today
/// </summary>
/// <param name="timeRange">Time range</param>
/// <param name="hostAppHandle">Hosting app handle: Master app or client app</param>
/// <param name="cursor">Read cursor</param>
/// <param name="limit">Number of items to return</param>
/// <returns>Topic feed entities</returns>
public async Task <IList <ITopicFeedEntity> > QueryPopularTopics(TimeRange timeRange, string hostAppHandle, int cursor, int limit)
{
CTStore store = await this.tableStoreManager.GetStore(ContainerIdentifier.PopularTopics);
RankFeedTable table = this.tableStoreManager.GetTable(ContainerIdentifier.PopularTopics, TableIdentifier.PopularTopicsFeed) as RankFeedTable;
string feedKey = this.GetPopularTopicsFeedKey(timeRange, hostAppHandle);
// convert our current API cursor (an int) to a CTStore cursor (a string). Note that CTStore cursors
// are offset by 1 from API cursors. This hack will be removed when we change our API to use string-based
// cursors.
string ctCursor;
if (cursor == 0)
{
ctCursor = null;
}
else
{
ctCursor = (cursor - 1).ToString();
}
var result = await store.QueryRankFeedReverseAsync(table, ContainerIdentifier.PopularTopics.ToString(), feedKey, ctCursor, limit);
var convertedResults = result.Select(item => StoreSerializers.MinimalTopicRankFeedEntityDeserialize(item.ItemKey));
return(convertedResults.ToList <ITopicFeedEntity>());
}
/// <summary>
/// Query popular topics min score
/// </summary>
/// <param name="timeRange">Time range</param>
/// <param name="hostAppHandle">Hosting app handle: Master app or client app</param>
/// <returns>Score of the last entity in popular topics feed</returns>
public async Task <long?> QueryPopularTopicsMinScore(TimeRange timeRange, string hostAppHandle)
{
CTStore store = await this.tableStoreManager.GetStore(ContainerIdentifier.PopularTopics);
RankFeedTable table = this.tableStoreManager.GetTable(ContainerIdentifier.PopularTopics, TableIdentifier.PopularTopicsFeed) as RankFeedTable;
string feedKey = this.GetPopularTopicsFeedKey(timeRange, hostAppHandle);
// querying the rank feed in reverse order with a null cursor and a limit of 1 extracts the min entry in the feed
var result = await store.QueryRankFeedReverseAsync(table, ContainerIdentifier.PopularTopics.ToString(), feedKey, null, 1);
if (result.Count > 0)
{
return((long)result.First().Score);
}
return(null);
}