Simple memcached helper for Sinatra.

sinatra-memcacher.rb

# Activate in a modular Sinatra app:
#
#  register Sinatra::Memcacher
#  set :memcacher_enabled, true
#  set :memcacher_expiry, 86400 

# Cache an action:
#
#  get '/' do
#    cache "index" do 
#      @articles = Article.public.all(order: 'posted_at DESC', limit: 10)
#      erb :index
#    end
#  end


require 'sinatra/base'
require 'memcached'

module Sinatra
  module Memcacher
    module Helpers
      def cache(key, &block)
        return block.call unless options.memcacher_enabled
                  
        begin
          output = memcached.get(key)
        rescue Memcached::NotFound
          output = block.call
          memcached.set(key, output, options.memcacher_expiry)
        end
        output
      end
      
      def expire(key)
        begin
          memcached.delete key
          true
        rescue Memcached::NotFound
          false
        end
      end
  
      private
  
      def memcached
        options.memcacher_client ||= Memcached.new(options.memcacher_server)
      end
    end
    
    def self.registered(app)
      app.helpers Memcacher::Helpers
      
      app.set :memcacher_client, nil
      app.set :memcacher_enabled, false
      app.set :memcacher_server, "127.0.0.1:11211"
      app.set :memcacher_expiry, 3600
    end
  end
  
  register Memcacher
end