用于ActiveStorage::DiskController的#show方法是difficult to override，但它可以完成。
一种更简单的方法是为现有的#show方法添加一个after_action回调函数，以便在调用Cache-Control方法时插入其头：

# config/initializers/active_storage.rb

require 'active_storage/current'

ActiveStorage::Current.url_options = { host: 'localhost', port: 3000 }

require 'active_storage/set_current'
require 'active_storage/base_controller'
require 'active_storage/file_server'
require 'active_storage/disk_controller'

class ActiveStorage::DiskController < ActiveStorage::BaseController
  after_action do
    response.set_header('Cache-Control', 'max-age=3600, public') if action_name == 'show'
  end
end

然后，请求ActiveStorage URL会在响应中返回自定义的Cache-Control标头值：

HTTP/1.1 200 OK
Cache-Control: max-age=3600, public
...