require "active_storage/blob" require "mini_magick" # Image blobs can have variants that are the result of a set of transformations applied to the original. class ActiveStorage::Variant attr_reader :blob, :variation delegate :service, to: :blob def initialize(blob, variation) @blob, @variation = blob, variation end def processed process unless service.exist?(key) self end def key "variants/#{blob.key}/#{variation.key}" end def url(expires_in: 5.minutes, disposition: :inline) service.url key, expires_in: expires_in, disposition: disposition, filename: blob.filename end private def process service.upload key, transform(service.download(blob.key)) end def transform(io) File.open MiniMagick::Image.read(io).tap { |image| variation.transform(image) }.path end end