require "active_storage/variant" class ActiveStorage::VariantsController < ActionController::Base def show if blob = find_signed_blob redirect_to ActiveStorage::Variant.new(blob, decoded_variation).processed.url(disposition: disposition_param) else head :not_found end end private def find_signed_blob ActiveStorage::Blob.find_signed(params[:signed_blob_id]) end def decoded_variation ActiveStorage::Variation.decode(params[:variation_key]) end def disposition_param params[:disposition].presence_in(%w( inline attachment )) || "inline" end end