Pianobar/LastFM Integration

pianobar-lastfm.rb

#!/usr/bin/env ruby
# coding: utf-8

require 'digest/md5'
require 'net/http'

class LastFM

  attr_reader :api_key, :secret, :session_key, :base_uri, :namespace

  BASE_URI = URI('http://ws.audioscrobbler.com/2.0')

  # Public: Return a new instance of the API object.
  #
  # api_key     - LastFM API key.
  # secret      - LastFM secret token.
  # session_key - Session token, if it's been cached.
  def initialize(api_key, secret, session_key = nil)
    @api_key     = api_key
    @secret      = secret
    @session_key = session_key unless session_key.nil?
  end

  # Public: Set the namespace for this interface.
  #
  # Returns self (for chaining).
  def namespace!(namespace)
    @namespace = namespace
    self
  end

  def method_missing(method, *args, &block)
    # If @namespace is nil, then we're just setting the namespace
    # and returning self because the next call will have an actual
    # LastFM method.
    if @namespace.nil?
      namespace!(method)
    else
      action = [@namespace, method.to_s].join('.')
      params = args.first.merge(api_key: @api_key, sk: @session_key, method: action)
      @namespace = nil

      Net::HTTP.post_form(BASE_URI, params.merge(api_sig: signature(params)))
    end
  end

  protected
  # Internal: Generate an auth signature from a set of params.
  #
  # Returns a signature string.
  def signature(params)
    Digest::MD5.hexdigest(params.map { |p| p.join }.sort.join + @secret)
  end
end

# Get track info from STDIN.
event = ARGV[0]
track = {}
STDIN.each_line { |l| track.store(*l.chomp.split('=', 2)) }

# Set up LastFM client.
fm = LastFM.new('api_key',
                'secret',
                'session_token')

# Handle events.
case event
# Scrobble songs on finish.
when 'songfinish'
  fm.track.scrobble(artist: track['artist'], track: track['title'],
                    timestamp: Time.now.utc.to_i, chosenByUser: false)

# Love songs on thumbs up.
when 'songlove'
  fm.track.love(artist: track['artist'], track: track['title'])

# Save current song to file for display in tmux and then update the now
# playing in LastFM.
when 'songstart'
  fpath = File.join(File.expand_path(File.dirname(__FILE__)), 'current-song.txt')
  File.open(fpath, 'w') do |f|
    f.write("#[fg=colour39]⮂#[bg=colour39,fg=colour8]♫  #{track['title']} - #{track['artist']} @ #{track['stationName']} #[fg=default,bg=default]")
  end

  fm.track.updateNowPlaying(artist: track['artist'], track: track['title'])
end