gistfile1.rb

class Image < ActiveRecord::Base
  COMMON_ATTACHMENT_OPTIONS = {
    :content_type => :image,
    :max_size => 1.megabyte,
    :thumbnails => {
      :thumbnail => "75x75!",
      :small => "100x",
      :medium => "240x",
      :large => "500x",
    }
  }

  has_attachment({
    :storage => :s3,
    :s3_access => :private
    }.merge(COMMON_ATTACHMENT_OPTIONS)
  )

  validates_as_attachment

  def self.new(args={})
    raise "use TempImage.new or TempImage.build instead" if self == Image
    super(args)
  end
  
  def public_filename(thumbnail = nil, expiration = 1.hour)
    authenticated_s3_url(thumbnail, :expires_in => expiration)
  end

  def proxy_public_filename(thumbnail = nil, expiration = 1.hour)
    unless self.thumbnail? # self é img original
      if thumbnail # quer algum thumb, outro registro
        img = TempImage.first(
          :conditions => {:parent_id => self.id, :thumbnail => thumbnail.to_s}
        ) # img é um thumbnail
        img.temporary? ?
          img.public_filename(nil) :
          self.public_filename(thumbnail, expiration)
      else # quer original
        self.temporary? ?
          TempImage.find(self.id).public_filename(thumbnail) :
          self.public_filename(thumbnail, expiration)
      end
    else # self é thumbnail
      self.temporary? ?
          TempImage.find(self.id).public_filename(nil) :
          self.public_filename(nil, expiration)
    end
  end

  def proxy
    temporary? ? TempImage.find(id) : self
  end

  def all_temporary?
    if thumbnail?
      ([parent.temporary?] + parent.thumbnails.map(&:temporary?)).uniq == [true]
    else
      ([temporary?] + thumbnails.map(&:temporary?)).uniq == [true]
    end
  end
  
end