Ruby on rails HTTP缓存与Rails+；机架：：缓存未失效

我的Rails 3应用程序生成的页面将在指定的时间段内更改，然后在其余生中保持静态（无更改）（想想：运动记分板）

这似乎是进行完整页面缓存的绝佳机会，因此我选择了Rack:：Cache，使用响应的最后修改部分来指示缓存何时无效

缓存工作得很好——太好了。即使最后修改的字段更新的日期/时间晚于请求和响应的If-Modified-Since字段生成的状态200（与304相反），浏览器仍然加载缓存在服务器上的页面版本

以下是我在服务器调试日志中看到的内容：

App 16638 stdout: Started GET "/games/2014/2/10" for xx.xx.xx.xxx at 2014-02-11 04:04:11 +0000
App 16638 stdout: Processing by GamesController#index as HTML
App 16638 stdout:   Parameters: {"year"=>"2014", "month"=>"2", "day"=>"10"}
App 16638 stdout:   Game Load (2.8ms)  SELECT "games".* FROM "games" WHERE "games"."date" = '2014-02-10'
App 16638 stdout:   Game Load (2.8ms)  SELECT "games".* FROM "games" WHERE "games"."id" = 877 LIMIT 1
App 16638 stdout:   Team Load (1.3ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 10 LIMIT 1
App 16638 stdout:   Team Load (0.7ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 23 LIMIT 1
App 16638 stdout:   Game Load (4.2ms)  SELECT "games".* FROM "games" WHERE "games"."id" = 875 LIMIT 1
App 16638 stdout:   Team Load (0.6ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 17 LIMIT 1
App 16638 stdout:   Team Load (5.4ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 2 LIMIT 1
App 16638 stdout:   Game Load (7.0ms)  SELECT "games".* FROM "games" WHERE "games"."id" = 874 LIMIT 1
App 16638 stdout:   Team Load (0.7ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 9 LIMIT 1
App 16638 stdout:   Team Load (7.9ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 27 LIMIT 1
App 16638 stdout:   Game Load (0.7ms)  SELECT "games".* FROM "games" WHERE "games"."id" = 876 LIMIT 1
App 16638 stdout:   Team Load (0.4ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 18 LIMIT 1
App 16638 stdout:   Team Load (0.4ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 11 LIMIT 1
App 16638 stdout:   Game Load (0.6ms)  SELECT "games".* FROM "games" WHERE "games"."id" = 873 LIMIT 1
App 16638 stdout:   Team Load (4.0ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 12 LIMIT 1
App 16638 stdout:   Team Load (0.6ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 8 LIMIT 1
App 16638 stdout:   Game Load (5.4ms)  SELECT "games".* FROM "games" WHERE "games"."id" = 872 LIMIT 1
App 16638 stdout:   Team Load (0.6ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 28 LIMIT 1
App 16638 stdout:   Team Load (3.9ms)  SELECT "teams".* FROM "teams" WHERE "teams"."id" = 19 LIMIT 1
App 16638 stdout: Latest game: 2014-02-11 03:44:50 UTC
App 16638 stdout: Cache read: views/xxxx/games/2014/2/10
App 16638 stdout: Dalli::Server#connect 127.0.0.1:11211
App 16638 stdout: Read fragment views/xxxxx/games/2014/2/10 2.6ms
App 16638 stdout: Completed 200 OK in 618.2ms (ActiveRecord: 128.8ms)
App 15100 stderr: cache: [GET /games/2014/2/10] stale, invalid, store
App 16638 stdout: Started GET "/assets/bootstrap.css" for 66.55.150.181 at 2014-02-11 04:04:12 +0000
App 16638 stdout: Served asset /bootstrap.css - 304 Not Modified (12ms)
App 15100 stderr: cache: [GET /assets/bootstrap.css] stale, valid, store
App 15100 stderr: cache: [GET /assets/application-85cd667c6ae785b5d80f452fe6ad811e.js] fresh
App 15100 stderr: cache: [GET /assets/application-50dd9f33494a58a079e7417a68763e42.css] fresh

以下是一个请求/响应示例（请参见200状态）：

在相关的控制器中，我对给定的操作使用before_过滤器，在该过滤器中，我在页面上最后更新的对象上使用fresh_。这似乎在响应中生成了正确的日期/时间，但我包含了所有可能错误的代码（为了简洁起见，我删除了show操作）：

class GamesController[：index]
缓存操作：索引
def set_index_cache_头
@date=今天的日期
如果参数[：年]&参数[：月]&参数[：日]
@日期=日期。新建（参数[：年]。到i，参数[：月]。到i，参数[：天]。到i）
其他的
最新游戏=游戏。其中（状态：[：最终，：进行中]）。顺序（“日期描述”）。首先
如果是最近的游戏！=无
@日期=最近的比赛日期
结束
结束
@games=Game.where（：date=>@date）.compact
@游戏信息=[]
@游戏。每个人都做|
@game_infos.push GameInfo.new（g.id）
结束
@最新游戏=@games.max_by{g|g.updated_at}
Rails.logger.debug“最新游戏：{@Latest_game.updated_at}”
新鲜时（@latest_game，public:true）
结束
def索引
结束
结束

如果我了解您正在尝试什么，我相信您需要将expires\u设置为in（最好设置为after\u筛选器，这样您就不会缓存状态为500的响应）。现在看来，rack cache正在无限期地缓存您的页面（或者不管默认值是什么），并且您的请求永远不会到达rails后端。Rack cache认为您的缓存是“新鲜的”，因此不必麻烦返回重新生成页面。这篇文章很好地解释了它的工作原理：

“fresh_when”仅在您实际通过机架缓存中间件并到达rails层时才被调用。如果您这样做，它将返回304，除非您更新您的记录（@latest_game）

---

希望对你有帮助，祝你好运！缓存失效是一个难题。

结果是控制器中的这一行：

caches_action :index

他是罪魁祸首。我的意图是只使用Rack:：Cache HTTP缓存，但此行激活Rails操作缓存，这不是我的意图。导致问题的原因是两个缓存系统一起运行。拆下此线路后，解决了问题

class GamesController < ApplicationController
  helper ApplicationHelper
  before_filter :set_index_cache_headers, :only => [:index]
  caches_action :index

  def set_index_cache_headers
    @date = Date.today

    if params[:year] && params[:month] && params[:day]
      @date = Date.new(params[:year].to_i, params[:month].to_i, params[:day].to_i)
    else
      most_recent_game = Game.where(status: [:final, :in_progress]).order("date DESC").first

      if most_recent_game != nil
        @date = most_recent_game.date
      end
    end

    @games = Game.where(:date => @date).compact

    @game_infos = []

    @games.each do |g|
      @game_infos.push GameInfo.new(g.id)
    end

    @latest_game = @games.max_by{|g| g.updated_at}

    Rails.logger.debug "Latest game: #{@latest_game.updated_at}"
    fresh_when(@latest_game, public: true)
  end

  def index

  end
end

caches_action :index