module RedisStore
  module Rack
    module Session
      # Redis session storage for Rails, and for Rails only. Derived from
      # the MemCacheStore code, simply dropping in Redis instead.
      #
      # Options:
      #  :key     => Same as with the other cookie stores, key name
      #  :secret  => Encryption secret for the key
      #  :host    => Redis host name, default is localhost
      #  :port    => Redis port, default is 6379
      #  :db      => Database number, defaults to 0. Useful to separate your session storage from other data
      #  :key_prefix  => Prefix for keys used in Redis, e.g. myapp-. Useful to separate session storage keys visibly from others
      #  :expire_after => A number in seconds to set the timeout interval for the session. Will map directly to expiry in Redis
      module Rails
        def initialize(app, options = {})
          # Support old :expires option
          options[:expire_after] ||= options[:expires]

          super

          @options = { :key_prefix => "" }.update(options)
          servers = [options[:servers]].flatten.compact.map do |server_options|
            {
              :namespace => 'rack:session',
              :host => 'localhost',
              :port => '6379',
              :db => 0
            }.update(Redis::Factory.convert_to_redis_client_options(server_options))
          end

          @pool = Redis::Factory.create(*servers)
        end

        private
        def prefixed(sid)
          "#{@options[:key_prefix]}#{sid}"
        end

        def get_session(env, sid)
          sid ||= generate_sid
          begin
            session = @pool.marshalled_get(prefixed(sid)) || {}
          rescue Errno::ECONNREFUSED
            session = {}
          end
          [sid, session]
        end

        def set_session(env, sid, session_data)
          options = env['rack.session.options']
          @pool.marshalled_set(prefixed(sid), session_data, options)
          return true
        rescue Errno::ECONNREFUSED
          return false
        end
      end
    end
  end
end

unless defined?(ActionDispatch) # rails 2.3.x
  class ActionController::Session::RedisSessionStore < ActionController::Session::AbstractStore
    include RedisStore::Rack::Session::Rails
  end
else # rails 3.x
  class ActionDispatch::Session::RedisSessionStore < ActionDispatch::Session::AbstractStore
    include RedisStore::Rack::Session::Rails
  end
end