Rails的Cache分四种:
1，Page Cache - Fastest
2，Action Cache - Next Fastest
3，Fragment Cache - Least Fastest
4，ActiveRecord Cache - Only available in Edge Rails
下面一一介绍上面四种Cache以及Rails如何使用memcached
一、Page Cache
如果开发阶段要使用cache，则需要先设置好config/environments/development.rb:
config.action_controller.perform_caching = true
class BlogController < ApplicationController
caches_page :list, :show
def list
Post.find(:all, \:order => "created_on desc", :limit => 10)
end
def show
@post = Post.find(params[:id])
end
end
Rails::Initializer.run do |config|
# ...
config.load_paths += %w(#{RAILS_ROOT}/app/sweepers)
# ...
class BlogSweeper < ActionController::Caching::Sweeper
observe Post # This sweeper is going to keep an eye on the Post model
# If our sweeper detects that a Post was created call this
def after_create(post)
expire_cache_for(post)
end
# If our sweeper detects that a Post was updated call this
def after_update(post)
expire_cache_for(post)
end
# If our sweeper detects that a Post was deletedcall this
def after_destroy(post)
expire_cache_for(post)
end
private
def expire_cache_for(record)
# Expire the list page now that we posted a new blog entry
expire_page(:controller => 'blog', :action => 'list')
# Also expire the show page, in case we just edit a blog entry
expire_page(:controller => 'blog', :action => 'show', :id => record.id)
end
end
class BlogController < ApplicationController
caches_page :list, :show
cache_sweeper :blog_sweeper, \:only => [:create, :update, :destroy]
# ...
end
config.action_controller.page_cache_directory = RAILS_ROOT + "/public/cache/"
class BlogController < ApplicationController
before_filter :authentication
caches_action :list, :show
cache_sweeper :blog_sweeper, \:only => [:create, :update, :destroy]
<strong>My Blog Posts</strong>
<% cache do %>
<ul>
<% for post in @posts %>
<li><%= link_to post.title, :controller => 'blog', :action => 'show', :id => post %></li>
<% end %>
</ul>
<% end %>
def list
unless read_fragment({})
@post = Post.find(:all, \:order => 'created_on desc', :limit => 10)
end
end
def list
unless read_fragment({:page => params[:page] || 1}) # Add the page param to the cache naming
@post_pages, @post = paginate :posts, :per_page => 10
end
end
<% cache ({:page => params[:page] || 1}) do %>
... All of the html to display the posts ...
<% end %>
cache ("turkey") => "/tmp/cache/turkey.cache"
cache (:controller => 'blog', :action => 'show', :id => 1) => "/tmp/cache/localhost:3000/blog/show/1.cache"
cache ("blog/recent_posts") => "/tmp/cache/blog/recent_posts.cache"
cache ("#{request.host_with_port}/blog/recent_posts") => "/tmp/cache/localhost:3000/blog/recent_posts.cache"
expire_fragment(:controller => 'blog', :action => 'list', :page => 1)
expire_fragment(%r{blog/list.*})
@tags = Tag.find :all
Cache.put 'all_your_tags', @tags
Cache.put 'favorite_skateboarder', 'Tom Penny'
skateboarder = Cache.get 'favorite_skateboarder'
Cache.delete 'all_your_tags'
sudo gem install cached_model
require 'cached_model'
memcache_options = {
:c_threshold => 10_000,
:compression => true,
:debug => false,
:namespace => 'my_rails_app',
:readonly => false,
:urlencode => false
}
CACHE = MemCache.new memcache_options
CACHE.servers = 'localhost:11211'
class Foo < CachedModel
end
all_foo = Foo.find :all
Cache.put 'Foo:all', all_foo
Cache.get 'Foo:all'
5，可以对每个app server启动一个memcached实例，分配128MB的内存对一般的程序来说足够
转载自：http://blog.csdn.net/aabbcc456aa/article/details/7681768
