comment_counter.rb

require 'nokogiri'

class CommentCounter
  
  def self.num_comments(params, xids)
    count = 0
    facemask = Facemask.new(:api_key => ENV['FACEBOOK_API_KEY'], :session_key => params[:fb_sig_session_key], :secret_key => ENV['FACEBOOK_SECRET_KEY'])

    xids.each do | xid |
      result = facemask.post('facebook.comments.get', {:xid=>xid})      
      doc = Nokogiri::XML(result)
      current_count = doc.search('comment').size
      puts "xid: #{xid} count: #{current_count}"
      count += current_count
    end    
    puts "total: #{count}"
    count
  end
  
end