Rails Action Caching用于用户特定的记录 [英] Rails Action Caching for user specific records

问题描述

我是Rails新手，正在尝试为我的应用程序实现缓存. 我安装了memcached并将其配置在我的development.rb中，如下所示:

I am a rails newbie trying to implement caching for my app. I installed memcached and configured it in my development.rb as follows:

config.action_controller.perform_caching             = true
config.cache_store = :mem_cache_store

我有一个控制器ProductsController，可以在用户登录时显示特定于用户的产品.

I have a controller ProductsController that shows user specific products when they are logged in.

class ProductsController < ApplicationController
  caches_action :index, :layout => false
  before_filter :require_user

  def index
    @user.products              
  end
end

The route for index action is: /products

问题是，当我以

1)第一次用户A，rails击中了我的控制器并缓存了产品操作.

1) User A for the first time, rails hits my controller and caches the products action.

2)我以用户B的身份注销并登录，它仍然以用户A的身份登录，并显示了用户A而非用户B的产品. 它甚至没有击中我的控制器.

2) I logout and login as User B, it still logs me in as User A and shows products for User A and not User B. It doesn't even hit my controller.

关键可能是路由，在我的内存缓存控制台中，我看到它是基于同一密钥获取的.

The key probably is the route, in my memcached console I see that it's fetching based on the same key.

20 get views/localhost:3000/products
20 sending key views/localhost:3000/products

动作缓存不是我应该使用的缓存吗?我将如何缓存和显示特定于用户的产品?

Is action caching not what I should use? How would I cache and display user specific products?

感谢您的帮助.

推荐答案

第一个问题是，您的require_user的before_filter在操作缓存之后，因此不会运行.要解决此问题，请使用以下控制器代码:

The first problem is that your before_filter for require_user is after the action caching, so that won't run. To fix that, use this controller code:

class ProductsController < ApplicationController
  before_filter :require_user
  caches_action :index, :layout => false

  def index
    @products = @user.products              
  end
end

第二，对于动作缓存，您正在执行与页面缓存完全相同的操作，但是在运行过滤器之后，您的@ user.products代码将不会运行.有两种方法可以解决此问题.

Second, for action caching you are doing the exact same thing as page caching, but after filters are run, so your @user.products code won't run. There are a couple of ways to fix this.

首先，如果需要，您可以根据传递给页面的参数来缓存操作.例如，如果传递user_id参数，则可以基于该参数进行缓存，如下所示:

First, if you want you can cache the action based on the parameters that are passed to the page. For example, if you pass a user_id parameter, you could cache based on that parameter like this:

caches_action :index, :layout => false, :cache_path => Proc.new { |c| c.params[:user_id] }

第二，如果要仅缓存查询而不是整个页面，则应完全删除操作缓存，而仅缓存查询，如下所示:

Second, if you want to simply cache the query and not the entire page, you should remove action caching entirely and only cache the query, like this:

def index
  @products = Rails.cache.fetch("products/#{@user.id}"){ @user.products }
end

这应该有助于您为每个用户使用单独的缓存.

This should help you get on your way to having a separate cache for each user.

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