/// <summary>
/// Gets the personalized video suggestions for a specific user.
/// </summary>
public async Task <Dtos.SuggestedVideos> GetSuggestions(SuggestedVideosQuery query)
{
// Return the output of a Spark job that runs periodically in the background to populate the video_recommendations table
// (see the /data/spark folder in the repo for more information)
PreparedStatement prepared = await _statementCache.NoContext.GetOrAddAsync(
"SELECT videoid, authorid, name, added_date, preview_image_location FROM video_recommendations WHERE userid=?");
IStatement bound = prepared.Bind(query.UserId)
.SetAutoPage(false)
.SetPageSize(query.PageSize);
// The initial query won't have a paging state, but subsequent calls should if there are more pages
if (string.IsNullOrEmpty(query.PagingState) == false)
{
bound.SetPagingState(Convert.FromBase64String(query.PagingState));
}
RowSet rows = await _session.ExecuteAsync(bound).ConfigureAwait(false);
return(new Dtos.SuggestedVideos()
{
UserId = query.UserId,
Videos = rows.Select(MapRowToVideoPreview).ToList(),
PagingState = rows.PagingState != null && rows.PagingState.Length > 0 ? Convert.ToBase64String(rows.PagingState) : null
});
}
/// <summary>
/// Gets the personalized video suggestions for a specific user.
/// </summary>
public Task <Dtos.SuggestedVideos> GetSuggestions(SuggestedVideosQuery query)
{
// TODO: Can we implement suggestions without DSE and Spark?
var result = new Dtos.SuggestedVideos()
{
UserId = query.UserId,
Videos = Enumerable.Empty <VideoPreview>(),
PagingState = null
};
return(Task.FromResult(result));
}
