libspotify: sometimes created playlists get no names

Question

I am using the latest version of the libspotify API (12.1.51). And I am coding using C# and libspotify.NET (a simple interop wrapper library for libspotify). I have built a program that creates playlists using the libspotify API. I am using the latest native Spotify client for Windows for checking my created playlists.

I have built a program that waits for a playlist name and a list of track URIs or one album URI and creates the corresponding playlist. If an album URI is supplied then all the tracks from the album will be added to the new playlist otherwise the supplied list of track URIs will be used to create the new playlist. The program waits until the callback

playlist_update_in_progress

is called and the done parameter equals true before accepting new playlists to create.

It works well except that sometimes the playlists are created with no names but do have all the tracks. I can just tell the program to create the exact same playlist that got no name and it might work the second time. It happens randomly but I have noticed that if I create about 200 playlists then maybe 5-10 playlists get no names. I can see the playlists being added in your Spotify client as the program is running and creating the playlists and randomly seeing playlists with no names. The playlists appear almost at the same time the callback is called and done equals true (not always of course, there might be a delay). I tried manually renaming the playlists in the Spotify client for Windows with no problems (the playlist name length was 0 or an empty string if you will). The native Spotify client does not even allow empty playlist names.

I use:

sp_playlistcontainer_add_new_playlist

to add a new playlist and I have tried using IntPtr and a C# string to pass to it. Tried both:

[DllImport("libspotify")]
public static extern IntPtr sp_playlistcontainer_add_new_playlist(IntPtr playlistContainerPtr, string name);

[DllImport("libspotify")]
public static extern IntPtr sp_playlistcontainer_add_new_playlist(IntPtr playlistContainerPtr, IntPtr namePtr);

And I have also tried

sp_playlist_rename

to rename the playlist several times (as some sort of fix) with no success. I do not know exactly what happens at the server when the playlists are created. Is this a bug or what is going on?

I have really tried a lot of hacks to make this work, but to no avail.

More info about the program:

First it connects to Spotify and then waits for some console input. It checks the input for the following strings:

To create a playlist using a name and a list of tracks:

createplaylistfromtracks "Tracks playlist" spotify:track:36MuLw248uzLPtrJ6073ZR spotify:track:5WPkvx0MARhlWhXp1sJg4k spotify:track:1VrdbSFVU9wJkuDM2sWYVe spotify:track:66RG0BBwpQqHxZs06UUyeo spotify:track:0zp3uPuhnARR1XYsgg5JLV

and to create a playlist using a name and a list of tracks from an album URI:

createplaylistfromalbum "Album playlist" spotify:album:5rVwDKRKa1FjDlLofDZyRb

And then the program parses the input and creates the playlist and settings a flag Busy = true so that the console will not read any input until Busy = false, which occurs when the playlist_update_in_progress callback is called and done is true. Then it reads input again...

Any help would be highly appreciated.

Can you check in our desktop client to see if the playlists appear there with the correct names? — iKenndac
That is exactly where I am checking and where I see that they do not have any playlist names. With "in my Spotify client" I meant your Spotify client. — user2050434
Hi again iKenndac. Thanks for taking your time to answer my question. I have attached a printscreen of the Spotify client, clearly showing the problem: dropbox.com/s/2bp7psw0874zvel/playlist_no_name.png I have also after creating the playlists, reading a list of all my playlists in my Spotify account like so: IEnumerable<PlaylistContainer.PlaylistInfo> list = PlaylistContainer.GetSessionContainer().GetAllPlaylists().Where(p => Playlist.Get(p.Pointer) != null && string.IsNullOrWhiteSpace(p.Name) || p.Name == "Playlist test!"); I get only 1 playlist which has Name = "" though! — user2050434
Oh and I am not sure but it just seems like some sort of a bug you have on your end. I did debug, and all my created playlist objects to have names. The same ones if you will. I have been debugging a lot. We really need this fixed as this utility will be very important at our company. — user2050434

iKenndac iKenndac · Accepted Answer · 2013-02-08T11:31:19

We have many applications running libspotify both internally and externally and we've had no problems like this with the library, which would suggest this isn't a bug in libspotify.

A few pointers that might cause this to happen:

Make sure you're managing threads properly. When you get a notify_main_thread() call (which arrives on some background thread), you must asynchronously call sp_sesion_process_events() from the main thread, so you need to make sure you're marshalling this over to the main thread properly. If this process isn't working properly, stuff will start acting weird.
Since you're doing many operations, make sure libspotify has time to synchronise all of your changes with the service. The playlist_update_in_progress is designed to notify you when multiple mutations are happening to the playlist, and is typically useful when changes are coming in from elsewhere. Instead, playlist_state_changed is what you need for listening to changes like that (typically, after a rename, I believe the playlists goes into a "loading" state while the change is applied, then back out (that is, sp_playlist_is_loading returns false again) once it's done.
Also, when you're exiting your application, make sure you perform a sp_session_logout() call and wait until the logged_out callback is fired before exiting. If you don't, some changes might not be synchronised with the service.

libspotify: sometimes created playlists get no names

1 Answers