ruby on rails 的redis 使用

Posted 2022-06-10 hexudong08

redis 是非常强大的key-value数据库，性能特别高，适合大规模数据处理。不过，据说其数据存在在内存中，所以，还是尽量的少放些数据到其中吧。最好只放一个id号。

1. 下载安装redis
   http://redis.io/download
   安装命令，大同小异
   

   curl -O http://redis.googlecode.com/files/redis-2.2.2.tar.gz
   tar xzf redis-2.2.2.tar.gz
   cd redis-2.2.2
   make
   cp src/redis-server src/redis-cli /usr/bin

2. 启动redis服务器
   

   redis-server

   或者
   

   redis-server   /path/to/redis.conf

   redis.conf的配置文件参看地址  安装目录下可以找到
   
3. redis for rails
   https://github.com/redis/redis-rb
   

4. gem install
   
   gem 'redis'  #rails3
   config.gem 'redis'    #rails2 
   
   

   
   
5. connect redis
   创建 redis.rb
   

   $redis = Redis.new(:host => 'localhost', :port => 6379)
   
   

   
   
6. 如下方法来自参考的链接
   

   class User < ActiveRecord::Base
     # follow a user
     def follow!(user)
       $redis.multi do
         $redis.sadd(self.redis_key(:following), user.id)
         $redis.sadd(user.redis_key(:followers), self.id)
       end
     end
     
     # unfollow a user
     def unfollow!(user)
       $redis.multi do
         $redis.srem(self.redis_key(:following), user.id)
         $redis.srem(user.redis_key(:followers), self.id)
       end
     end
     
     # users that self follows
     def followers
       user_ids = $redis.smembers(self.redis_key(:followers))
       User.where(:id => user_ids)
     end
   
     # users that follow self
     def following
       user_ids = $redis.smembers(self.redis_key(:following))
       User.where(:id => user_ids)
     end
   
     # users who follow and are being followed by self
     def friends
       user_ids = $redis.sinter(self.redis_key(:following), self.redis_key(:followers))
       User.where(:id => user_ids)
     end
   
     # does the user follow self
     def followed_by?(user)
       $redis.sismember(self.redis_key(:followers), user.id)
     end
     
     # does self follow user
     def following?(user)
       $redis.sismember(self.redis_key(:following), user.id)
     end
   
     # number of followers
     def followers_count
       $redis.scard(self.redis_key(:followers))
     end
   
     # number of users being followed
     def following_count
       $redis.scard(self.redis_key(:following))
     end
     
     # helper method to generate redis keys
     def redis_key(str)
       "user:#self.id:#str"
     end
   end
   

   
   follow, following 关系体现在redis 中
7. redis还能用于 缓存
   https://github.com/jodosha/redis-store
   
   
   
   
   
   
   
   
   
   
   

参考：
http://redis.io/

http://jimneath.org/2011/03/24/using-redis-with-ruby-on-rails.html
https://github.com/redis/redis-rb

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