orbit-basic/app/models/asset.rb

class Asset

  include MongoMapper::Document
  include Grip::HasAttachment

  key :filename, String, :required => true
  key :description, String

  has_grid_attachment :data, :required => true
  
  before_validation :setup_filename
  after_save :save_static_file
  after_destroy :delete_static_file
  
  def url
    "/assets/#{self.filename}"
  end
  
  def location
    "#{RAILS_ROOT}/public/assets/#{self.filename}"
  end
  
  protected
  
  def setup_filename
    if self.filename.blank? && self.data
      self.filename = self.data.file_name
    end
  end
  
  def save_static_file
    f = File.new(self.location, "wb")
    f.write(self.data.file.read)
    f.close
  end
  
  def delete_static_file
    File.delete(self.location) rescue nil
  end
  
end