# frozen_string_literal: true module Gitlab module Search # This is an abstract class used for storing/searching recently viewed # items. The #type and #finder methods are the only ones needed to be # implemented by classes inheriting from this. class RecentItems ITEMS_LIMIT = 100 EXPIRES_AFTER = 7.days def initialize(user:, items_limit: ITEMS_LIMIT, expires_after: EXPIRES_AFTER) @user = user @items_limit = items_limit @expires_after = expires_after end def log_view(item) with_redis do |redis| redis.zadd(key, Time.now.to_f, item.id) redis.expire(key, @expires_after) # There is a race condition here where we could end up removing an # item from 2 places concurrently but this is fine since worst case # scenario we remove an extra item from the end of the list. if redis.zcard(key) > @items_limit redis.zremrangebyrank(key, 0, 0) # Remove least recent end end end def search(term) ids = with_redis do |redis| redis.zrevrange(key, 0, @items_limit - 1) end.map(&:to_i) finder.new(@user, search: term, in: 'title').execute.reorder(nil).id_in_ordered(ids) # rubocop: disable CodeReuse/ActiveRecord end private def with_redis(&blk) Gitlab::Redis::SharedState.with(&blk) # rubocop: disable CodeReuse/ActiveRecord end def key "recent_items:#{type.name.downcase}:#{@user.id}" end def type raise NotImplementedError end def finder raise NotImplementedError end end end end