asciinema.org/app/models/asciicast.rb

class Asciicast < ActiveRecord::Base
  mount_uploader :stdin, BasicUploader
  mount_uploader :stdin_timing, BasicUploader
  mount_uploader :stdout, BasicUploader
  mount_uploader :stdout_timing, BasicUploader

  validates :stdout, :stdout_timing, :presence => true
  validates :terminal_columns, :terminal_lines, :duration, :presence => true

  belongs_to :user
  has_many :comments, :order => :created_at, :dependent => :destroy

  scope :featured, where(:featured => true)

  before_create :assign_user, :unless => :user

  attr_accessible :meta, :stdout, :stdout_timing, :stdin, :stdin_timing,
                  :title, :description

  def self.assign_user(user_token, user)
    where(:user_id => nil, :user_token => user_token).
    update_all(:user_id => user.id, :user_token => nil)
  end

  def meta=(file)
    data = JSON.parse(file.tempfile.read)

    self.username         = data['username']
    self.user_token       = data['user_token']
    self.duration         = data['duration']
    self.recorded_at      = data['recorded_at']
    self.title            = data['title']
    self.command          = data['command']
    self.shell            = data['shell']
    self.uname            = data['uname']
    self.terminal_lines   = data['term']['lines']
    self.terminal_columns = data['term']['columns']
    self.terminal_type    = data['term']['type']
  end

  def os
    if uname =~ /Linux/
      'Linux'
    elsif uname =~ /Darwin/
      'OSX'
    else
      uname.split(' ', 2)[0]
    end
  end

  def shell_name
    File.basename(shell.to_s)
  end

  def as_json(opts = {})
    super :methods => [:escaped_stdout_data, :stdout_timing_data]
  end

  def escaped_stdout_data
    if data = stdout.read
      data.bytes.map { |b| '\x' + format('%02x', b) }.join
    else
      nil
    end
  end

  def stdout_timing_data
    if data = stdout_timing.read
      Bzip2.uncompress(data).lines.map do |line|
        delay, n = line.split
        [delay.to_f, n.to_i]
      end
    else
      nil
    end
  end

  def assign_user
    if user_token.present?
      if ut = UserToken.find_by_token(user_token)
        self.user = ut.user
        self.user_token = nil
      end
    end
  end
end