public IObservable <IReadOnlyList <SoundCloudSong> > GetSongsAsync(string searchTerm = null)
{
searchTerm = searchTerm ?? string.Empty;
IObservable <IReadOnlyList <SoundCloudSong> > retrievalFunc = Observable.Defer(() =>
requestCache.GetOrFetchObject(BlobCacheKeys.GetKeyForSoundCloudCache(searchTerm), () =>
string.IsNullOrWhiteSpace(searchTerm) ? GetPopularSongs() : SearchSongs(searchTerm), DateTimeOffset.Now + CacheDuration));
return(retrievalFunc.Catch <IReadOnlyList <SoundCloudSong>, Exception>(ex =>
Observable.Throw <IReadOnlyList <SoundCloudSong> >(new NetworkSongFinderException("SoundCloud search failed", ex)))
.Select(x => x.Where(y => y.IsStreamable || y.IsDownloadable).ToList())
.Do(SetupSongUrls));
}
