Fixed RedisSessionStore for Rails 3.2

redis_session_store.rb

require 'redis'

# 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
#  :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

class RedisSessionStore < ActionDispatch::Session::AbstractStore

  def initialize(app, options = {})
    super

    @redis = Redis.new(options)
  end

  def get_session(env, sid)
    sid ||= generate_sid
    begin
      data = @redis.get(prefixed(sid))
      session = data.nil? ? {} : Marshal.load(data)
    rescue Errno::ECONNREFUSED
      session = {}
    end
    [sid, session]
  end
  
  def set_session(env, sid, session, options)
    expiry  = options[:expire_after] || nil
    if session
      if expiry
        @redis.setex(prefixed(sid), expiry, Marshal.dump(session))
      else
        @redis.set(prefixed(sid), Marshal.dump(session))
      end
    else
      @redis.del(prefixed(sid))
    end
    sid
  rescue Errno::ECONNREFUSED
    return false
  end
  
  # Remove a session from the cache.
  def destroy_session(env, sid, options)
    @redis.del(prefixed(sid))
    generate_sid
  end

  private

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

end