mirror of
https://github.com/discourse/discourse.git
synced 2024-11-27 21:03:46 +08:00
30990006a9
This reduces chances of errors where consumers of strings mutate inputs and reduces memory usage of the app. Test suite passes now, but there may be some stuff left, so we will run a few sites on a branch prior to merging
101 lines
2.2 KiB
Ruby
101 lines
2.2 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
class RandomTopicSelector
|
|
|
|
BACKFILL_SIZE = 3000
|
|
BACKFILL_LOW_WATER_MARK = 500
|
|
|
|
def self.backfill(category = nil)
|
|
exclude = category&.topic_id
|
|
|
|
options = {
|
|
per_page: category ? category.num_featured_topics : 3,
|
|
visible: true,
|
|
no_definitions: true
|
|
}
|
|
|
|
options[:except_topic_ids] = [category.topic_id] if exclude
|
|
|
|
if category
|
|
options[:category] = category.id
|
|
# NOTE: at the moment this site setting scopes tightly to a category (excluding subcats)
|
|
# this is done so we don't populate a junk cache
|
|
if SiteSetting.limit_suggested_to_category
|
|
options[:no_subcategories] = true
|
|
end
|
|
|
|
# don't leak private categories into the "everything" group
|
|
options[:guardian] = Guardian.new(CategoryFeaturedTopic.fake_admin)
|
|
end
|
|
|
|
query = TopicQuery.new(nil, options)
|
|
|
|
results = query.latest_results.order('RANDOM()')
|
|
.where(closed: false, archived: false)
|
|
.where("topics.created_at > ?", SiteSetting.suggested_topics_max_days_old.days.ago)
|
|
.limit(BACKFILL_SIZE)
|
|
.reorder('RANDOM()')
|
|
.pluck(:id)
|
|
|
|
key = cache_key(category)
|
|
|
|
if results.present?
|
|
$redis.multi do
|
|
$redis.rpush(key, results)
|
|
$redis.expire(key, 2.days)
|
|
end
|
|
end
|
|
|
|
results
|
|
end
|
|
|
|
def self.next(count, category = nil)
|
|
key = cache_key(category)
|
|
|
|
results = []
|
|
|
|
return results if count < 1
|
|
|
|
results = $redis.multi do
|
|
$redis.lrange(key, 0, count - 1)
|
|
$redis.ltrim(key, count, -1)
|
|
end
|
|
|
|
if !results.is_a?(Array) # Redis is in readonly mode
|
|
results = $redis.lrange(key, 0, count - 1)
|
|
else
|
|
results = results[0]
|
|
end
|
|
|
|
results.map!(&:to_i)
|
|
|
|
left = count - results.length
|
|
|
|
backfilled = false
|
|
if left > 0
|
|
ids = backfill(category)
|
|
backfilled = true
|
|
results += ids[0...count]
|
|
results.uniq!
|
|
results = results[0...count]
|
|
end
|
|
|
|
if !backfilled && $redis.llen(key) < BACKFILL_LOW_WATER_MARK
|
|
Scheduler::Defer.later("backfill") do
|
|
backfill(category)
|
|
end
|
|
end
|
|
|
|
results
|
|
end
|
|
|
|
def self.cache_key(category = nil)
|
|
"random_topic_cache_#{category&.id}"
|
|
end
|
|
|
|
def self.clear_cache!
|
|
$redis.delete_prefixed(cache_key)
|
|
end
|
|
|
|
end
|