May 10th, 2007

Scrobbler: Last.fm For Ruby

I enjoy having my life broadcast on the net and one essential part of that is music. A few weeks ago, I started working on a ruby library for accessing the audioscrobbler web services.

Last night I put the finishing touches on the first release so I thought I would say something here. If you have a last.fm profile and are logging your tunes, you can now access them using ruby with my scrobbler gem.

So how easy is it? Below are a few examples of how to work with users, artists, albums and tracks.

# get recent tracks for a user
user = Scrobbler::User.new('jnunemaker')
user.recent_tracks.each { |t| puts t.name }

# get all the tracks for an album
album = Scrobbler::Album.new('Carrie Underwood', 'Some Hearts', :include_info => true)
album.tracks.each { |t| puts t.name }

# get similar artists
artist = Scrobbler::Artist.new('Carrie Underwood')
artist.similar.each { |a| puts "(#{a.match}%) #{a.name}" }

# top albums for a tag
tag = Scrobbler::Tag.new('country')
tag.top_albums.each { |a| puts "(#{a.count}) #{a.name} by #{a.artist}" }

# top fans for a track
track = Scrobbler::Track.new('Carrie Underwood', 'Before He Cheats')
track.fans.each { |u| puts "(#{u.weight}) #{u.username}" }

I implemented pretty much everything but the group stuff. I don’t use groups so I didn’t feel like throwing it together. It probably would have been pretty easy and patches are welcome (svn repo).

This is my fifth gem and it’s really fun for me to look back and see how far I’ve come in ruby. The first was Magnolia (June 2, 2006) which had 0 tests. Yep, back then I hadn’t even heard of tests. Each gem since then has had more tests and I really feel that Scrobbler is my best to date. I mocked the class that hits audioscrobbler to instead read an xml fixture file which is kind of cool. If the services change in the future, I just have to put in a new xml file and get my tests passing again. I’m thinking in the next web service gem I’ll do something along the lines of this Scott Raymond comment. I really don’t know how I survived without tests back in my PHP and ColdFusion days.

At any rate, enjoy the gem and let me know if you do anything cool with it.

Posted by jnunemaker

Tagged: api, audioscrobbler, lastfm, music, web services

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23 Responses to “Scrobbler: Last.fm For Ruby”

William H. Harle Jr.
May 10, 2007

I can’t wait to use this John. Well done sir.
sol
May 11, 2007

thanks very much!
jeroen
May 16, 2007

sweet
Christian Dalager
May 16, 2007

Cool! I’ll just throw away my inferior wrapper ;-)
Konstantin Tumalevich
May 23, 2007

ooops … i have error.

ruby album.rb /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:404:in `to_constant_name’: Anonymous modules have no name to be referenced by (ArgumentError) from /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:214:in `qualified_name_for’ from /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:476:in `const_missing’ from /usr/local/lib/site_ruby/1.8/scrobbler/base.rb:9:in `connection’ from /usr/local/lib/site_ruby/1.8/scrobbler/base.rb:13:in `fetch_and_parse’ from /usr/local/lib/site_ruby/1.8/scrobbler/album.rb:107:in `load_info’ from /usr/local/lib/site_ruby/1.8/scrobbler/album.rb:99:in `initialize’ from album.rb:4
John Nunemaker
May 23, 2007

@Konstantin – What are you calling to when you get that error. Can you paste the code in?
Jason
May 29, 2007

I removed my dependency on xmlsimple, I stopped parsing out the recenttracks.xml file powering my dynamic “Most Recently Played” sig, and just moved to a call with your library.

It’s down to 34 lines (down from 43 in PHP w/ GD IIRC).

http://vxjasonxv.com/images/lastfm.png

The image uses Ruby (duh), RMagick for all the text annotation and image rendering, and your lib. Hey, I can get rid of my net/http dependency too.

33 lines :).

I do need to work something in in order to see if I should even get the xml file / regenerate the image or not. (I guess this means I have to go curl -I’ing it and see if AudioScrobbler puts out reliable “Last-Modified” headers.)
John Nunemaker
May 30, 2007

@Jason – Sweet. Nice work. Fun to see people using my libs.
Konstantin Tumalevich
Jun 03, 2007

i`m executing example from gem on Ubuntu Linux.
Jason
Jul 17, 2007

John,

I believe I may have found an HTML entity problem. I left a static copy of the image on Webshots:

Take a look at Huey Lewis & the News http://aycu34.webshots.com/image/22313/2006317658898393236_rs.jpg

I don’t think you mean for that literal & to be appearing.

I’m assuming that the library isn’t converting the XML character data to the single character entities?
Jason
Jul 17, 2007

Clearly I meant XML entity, or perhaps character entity, by the way.
Ray
Aug 11, 2007

Were you able to generate the flash player for the music? Thanks.

Nikola

Sep 21, 2007

Hi, thanks for your work…

I’ve found that if profile isn’t complete load_profile() script breakes.

So I modified it: :)

def load_profile
  doc = self.class.fetch_and_parse("#{api_path}/profile.xml")
  @id = (doc).at(:profile)['id']
  @cluster = (doc).at(:profile)['cluster']
  @url = (doc).at(:url).inner_html
  if ((doc).at(:realname)) : @realname = (doc).at(:realname).inner_html end
  if ((doc).at(:mbox_sha1sum)) : @mbox_sha1sum = (doc).at(:mbox_sha1sum).inner_html end
  @registered = (doc).at(:registered).inner_html
  @registered_unixtime = (doc).at(:registered)['unixtime']
  if ((doc).at(:age)) : @age = (doc).at(:age).inner_html end
  if ((doc).at(:gender)) : @gender = (doc).at(:gender).inner_html end
  if ((doc).at(:country)) : @country = (doc).at(:country).inner_html end
  @playcount = (doc).at(:playcount).inner_html
  if ((doc).at(:avatar)) : @avatar = (doc).at(:avatar).inner_html end
end

...but I have another problem, constant timeout… I can’t do more that few requests (I’m sleep()-ing as a real gentleman), how can I solve this?

Thanks again, Nikola

josh
Oct 20, 2007

Awesome John. I started writing this myself until I came to my senses and googled it. Very, very nice implementation!

thx
John Nunemaker
Oct 25, 2007

Glad I could help. Hopefully I’ll get to use it some day. :)
sanjay
Oct 31, 2007

Hiya. Is there a way to see if a band is actually in the scrobbler system?

I can ask for their top albums, to see if anything comes back, but that seems kinda silly.

thanks, sanj
John Nunemaker
Oct 31, 2007

@sanjay – Nope. Scrobbler doesn’t have an API method for that purpose, at least not that they have documented.
Georg Wacker
Jan 26, 2008

I made a little addition to Scrobbler::Artist that will enable getting the artist cover from which you are referencing.

bc. def image doc = self.class.fetch_and_parse(”#{api_path}/similar.xml”) return (doc).at(:similarartists)[‘picture’] end
Leon Bogaert
Apr 28, 2008

Is it also possible to add a song to you “Recently Listened Tracks” with this library?

Thanks in advance!
John Nunemaker
May 02, 2008

@Leon – Nope. Only read, no write.
nic h
Jun 13, 2008

arg, i dont understand how to use this :( it seems like what im looking for, but im clueless about ruby. any hints to get me in the right direction?
John Nunemaker
Jun 15, 2008

@nic – what is confusing you? http://scrobbler.rubyforge.org/ has a bit more on installation and such. not sure i can help unless you are more specific.
nic h
Jun 17, 2008
well im not really familiar with ruby (although i do use your twitter script and its awesome)

im not sure how to use this though. like this:
1. get recent tracks for a user user = Scrobbler::User.new(‘jnunemaker’) user.recent_tracks.each { |t| puts t.name }
what do you do with that? sorry, im just ignorant on this subject lol. i did look at all the documentation. does it go in a text file or what? how do you call it?