How to find out the current song playing on Spotify from an iOS app?

Question

I'm developing an iOS app that needs to get the artist's name and the song's title from a track playing on Spotify in background.

This is the flow:

1. User is listening something on Spotify (web or native app)
2. User opens my app
3. App finds out which track is playing
4. Another track plays
5. App detects this and get the new track metadata

I tried to get that using the MediaPlayer framework (MPMusicPlayerController class) but nothing happens.

I looked in the Spotify SDK Api reference and found nothing too.

Is it possible ?

Thanks!