ruby-on-rails - Heroku Cedar Stack - 机架缓存头文件

Question

我这辈子都想不通。尝试使用 Rack::Cache 来缓存我在 Heroku 上的一些静态公共(public)页面，除了做 Action 缓存以防它通过反向代理。

例如，这是我的“home”操作中的代码:

class StaticPagesController < ApplicationController
  layout 'public'

  caches_action :about, :contact, ......, :home, .....

  ......

  def home
    last_modified = File.mtime("#{Rails.root}/app/views/static_pages/home.html.haml")
    fresh_when last_modified: last_modified , public: true, etag: last_modified
    expires_in 10.seconds, :public => true       
  end

出于所有意图和目的，这应该有一个最大年龄为 10 的公共(public)缓存控制标签，不是吗？

$ curl -I http://myapp-staging.herokuapp.com/

HTTP/1.1 200 OK
Cache-Control: max-age=0, private, must-revalidate
Content-Type: text/html; charset=utf-8
Date: Thu, 24 May 2012 06:50:45 GMT
Etag: "997dacac05aa4c73f5a6861c9f5a9db0"
Status: 200 OK
Vary: Accept-Encoding
X-Rack-Cache: stale, invalid
X-Request-Id: 078d86423f234da1ac41b418825618c2
X-Runtime: 0.005902
X-Ua-Compatible: IE=Edge,chrome=1
Connection: keep-alive

我做错了什么可怕的事情吗？我觉得那个陈旧、无效的缓存响应有些问题……那是我第四次点击该页面。

配置信息:

# Use a different cache store in production
config.cache_store = :dalli_store

config.action_dispatch.rack_cache = {
  :verbose      => true,
  :metastore => "memcached://#{ENV['MEMCACHE_SERVERS']}",
  :entitystore => "memcached://#{ENV['MEMCACHE_SERVERS']}"#,
}

# OLD : Disable Rails's static asset server (Apache or nginx will already do this)
config.serve_static_assets = true
config.static_cache_control = "public, max-age=2592000"

(也许有一种方法可以手动设置缓存控制 header ？似乎应该有一种更简单的方法)。

更新

我什至尝试将 Controller 操作降至最低:

def home
  expires_in 10.seconds, :public => true
  #last_modified = File.mtime("#{Rails.root}/app/views/static_pages/home.html.haml")
  #fresh_when last_modified: last_modified , public: true, etag: last_modified
end

而且它不起作用...

HTTP/1.1 200 OK
Server: nginx
Date: Thu, 24 May 2012 19:15:18 GMT
Content-Type: text/html; charset=utf-8
Connection: keep-alive
Status: 200 OK
X-Ua-Compatible: IE=Edge,chrome=1
Etag: "733798214c652f39ae79b4037e9111dc"
Cache-Control: max-age=0, private, must-revalidate
X-Request-Id: b33087fe0c2ae986c4cac88f14420b7c
X-Runtime: 0.006000
X-Rack-Cache: stale, invalid
Vary: Accept-Encoding
X-Varnish: 349105873
Age: 0
Via: 1.1 varnish

!

Answer 1

也许重新考虑整个事情，只使用rails缓存。新的 cache_digests gem 应该让在 rails 级别做你想做的事情变得微不足道:
https://github.com/rails/cache_digests

我敢打赌，这将击败您的方法，包括执行文件系统调用以每 10 秒检查一次文件时间戳。