private IEnumerable <Album> Filter(ICollection <Album> albums, SearchAlbumsQuery query)
{
if (query.UserId.HasValue)
{
if (query.UserId < 1)
{
// Depending on requirements you may wish to treat 0 as empty or throw a
// custom validation exception that can be caught and handled in the api
// layer, or use model validation/attributes on the query
throw new Exception("Invalid UserId. UserId cannot be less than 1.");
}
_logger.LogDebug("Filtering by userid {UserId}", nameof(query.UserId));
return(albums.Where(a => a.UserId == query.UserId));
}
return(albums);
}
public async Task <ICollection <Album> > ExecuteAsync(SearchAlbumsQuery query)
{
_logger.LogInformation("Executing query {QueryType}", typeof(SearchAlbumsQuery).Name);
if (query == null)
{
throw new ArgumentNullException();
}
var albumTask = _mediaRepository.GetAlbumsAsync();
var photoTask = _mediaRepository.GetPhotosAsync();
await Task.WhenAll(albumTask, photoTask);
var albums = await albumTask;
var photos = await photoTask;
var filteredAlbums = Filter(albums, query);
var mappedResult = Map(filteredAlbums, photos);
_logger.LogDebug("Found {NumAlbums} albums", nameof(mappedResult.Count));
return(mappedResult);
}