quick and dirty cache for popular tags result

Gemfile

@@ -38,6 +38,7 @@ gem 'will_paginate'
 gem 'simpleidn'
 gem 'gandi'
 gem 'hoe', '3.14.2', require: nil
+gem 'msgpack'
 
 platform :mri, :rbx do
   gem 'magic' # sudo apt-get install file, For OSX: brew install libmagic

Gemfile.lock

@@ -101,6 +101,7 @@ GEM
       ruby-progressbar
     mocha (1.1.0)
       metaclass (~> 0.0.1)
+    msgpack (0.7.5)
     multi_json (1.11.2)
     net-scp (1.2.1)
       net-ssh (>= 2.6.5)
@@ -259,6 +260,7 @@ DEPENDENCIES
   minitest
   minitest-reporters
   mocha
+  msgpack
   paypal-recurring
   pg
   poltergeist
@@ -297,3 +299,6 @@ DEPENDENCIES
   webmock
   will_paginate
   zipruby
+
+BUNDLED WITH
+   1.11.2

environment.rb

@@ -62,6 +62,9 @@ Sidekiq.configure_client do |config|
   config.redis = sidekiq_redis_config
 end
 
+$redis = Redis.new
+$redis_cache = Redis::Namespace.new :cache, redis: $redis
+
 # :nocov:
 if ENV['RACK_ENV'] == 'development'
   # Run async jobs immediately in development.

models/tag.rb

@@ -23,6 +23,14 @@ class Tag < Sequel::Model
   end
 
   def self.popular_names(limit=10)
-    DB["select tags.name,count(*) as c from sites_tags inner join tags on tags.id=sites_tags.tag_id where tags.name != '' and tags.is_nsfw='f' group by tags.name having count(*) > 1 order by c desc LIMIT ?", limit].all
+    cache = $redis_cache.get :tag_popular_names
+    if cache.nil?
+      res = DB["select tags.name,count(*) as c from sites_tags inner join tags on tags.id=sites_tags.tag_id where tags.name != '' and tags.is_nsfw='f' group by tags.name having count(*) > 1 order by c desc LIMIT ?", limit].all
+      $redis_cache.set :tag_popular_names, res.to_msgpack
+      $redis_cache.expire :tag_popular_names, 86400 # 24 hours
+    else
+      res = MessagePack.unpack cache, symbolize_keys: true
+    end
+    res
   end
 end