jam-cloud/ruby/lib/jam_ruby/models/jam_track_right.rb

module JamRuby

  # describes what users have rights to which tracks
  class JamTrackRight < ActiveRecord::Base
    include JamRuby::S3ManagerMixin
  	attr_accessible :user, :jam_track, :user_id, :jam_track_id, :url, :md5, :length, :download_count
    belongs_to :user, class_name: "JamRuby::User"  # the owner, or purchaser of the jam_track
    belongs_to :jam_track, class_name: "JamRuby::JamTrack"

    validates :user, presence:true
    validates :jam_track, presence:true
    validate :verify_download_count

    validates_uniqueness_of     :user_id, scope: :jam_track_id
    
    # Uploads the JKZ:
    mount_uploader :url, JamTrackRightUploader
    before_destroy :delete_s3_files

    MAX_JAM_TRACK_DOWNLOADS = 1000

    def store_dir
      "#{jam_track.store_dir}/rights"
    end

    # create name of the file
    def filename
      "#{jam_track.name}.jkz"
    end
    
    def verify_download_count
      if (self.download_count < 0 || self.download_count > MAX_JAM_TRACK_DOWNLOADS) && !@current_user.admin
        errors.add(:download_count, "must be less than or equal to #{MAX_JAM_TRACK_DOWNLOADS}")
      end
    end

    def self.ready_to_clean
      JamTrackRight.where("downloaded_since_sign=? AND updated_at <= ?", true, 5.minutes.ago).limit(1000)      
    end

    def finish_sign(length, md5)
      self.last_signed_at = Time.now
      self.length = length
      self.md5 = md5
      self.signed = true
      if save
        Notification.send_jam_track_sign_complete(self)
      else
        raise "Error sending notification #{self.errors}"
      end      
    end

    # creates a short-lived URL that has access to the object.
    # the idea is that this is used when a user who has the rights to this tries to download this JamTrack
    # we would verify their rights (can_download?), and generates a URL in response to the click so that they can download
    # but the url is short lived enough so that it wouldn't be easily shared
    def sign_url(expiration_time = 120)
      s3_manager.sign_url(self[:url], {:expires => expiration_time, :secure => false})
    end

    def delete_s3_files
      remove_url!      
    end

    def enqueue
      begin
        Resque.enqueue(JamTracksBuilder, self.id)
      rescue Exception => e
        # implies redis is down. we don't update started_at by bailing out here
        false
      end

      # avoid db validations
      JamTrackRight.where(:id => self.id).update_all(:last_downloaded_at => Time.now)

      true
    end

    def update_download_count(count=1)
      self.download_count = self.download_count + count
      self.last_downloaded_at = Time.now
    end
    
  end
end