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metu.life/app/lib/feed_manager.rb

273 lines
11 KiB

# frozen_string_literal: true
require 'singleton'
class FeedManager
include Singleton
MAX_ITEMS = 400
# Must be <= MAX_ITEMS or the tracking sets will grow forever
REBLOG_FALLOFF = 40
def key(type, id, subtype = nil)
return "feed:#{type}:#{id}" unless subtype
"feed:#{type}:#{id}:#{subtype}"
end
def filter?(timeline_type, status, receiver_id)
if timeline_type == :home
filter_from_home?(status, receiver_id)
elsif timeline_type == :mentions
filter_from_mentions?(status, receiver_id)
else
false
end
end
def push_to_home(account, status)
return false unless add_to_feed(:home, account.id, status)
trim(:home, account.id)
PushUpdateWorker.perform_async(account.id, status.id, "timeline:#{account.id}") if push_update_required?("timeline:#{account.id}")
true
end
def unpush_from_home(account, status)
return false unless remove_from_feed(:home, account.id, status)
Redis.current.publish("timeline:#{account.id}", Oj.dump(event: :delete, payload: status.id.to_s))
true
end
def push_to_list(list, status)
return false unless add_to_feed(:list, list.id, status)
trim(:list, list.id)
PushUpdateWorker.perform_async(list.account_id, status.id, "timeline:list:#{list.id}") if push_update_required?("timeline:list:#{list.id}")
true
end
def unpush_from_list(list, status)
return false unless remove_from_feed(:list, list.id, status)
Redis.current.publish("timeline:list:#{list.id}", Oj.dump(event: :delete, payload: status.id.to_s))
true
end
def trim(type, account_id)
timeline_key = key(type, account_id)
reblog_key = key(type, account_id, 'reblogs')
# Remove any items past the MAX_ITEMS'th entry in our feed
redis.zremrangebyrank(timeline_key, '0', (-(FeedManager::MAX_ITEMS + 1)).to_s)
# Get the score of the REBLOG_FALLOFF'th item in our feed, and stop
# tracking anything after it for deduplication purposes.
falloff_rank = FeedManager::REBLOG_FALLOFF - 1
falloff_range = redis.zrevrange(timeline_key, falloff_rank, falloff_rank, with_scores: true)
falloff_score = falloff_range&.first&.last&.to_i || 0
# Get any reblogs we might have to clean up after.
redis.zrangebyscore(reblog_key, 0, falloff_score).each do |reblogged_id|
# Remove it from the set of reblogs we're tracking *first* to avoid races.
redis.zrem(reblog_key, reblogged_id)
# Just drop any set we might have created to track additional reblogs.
# This means that if this reblog is deleted, we won't automatically insert
# another reblog, but also that any new reblog can be inserted into the
# feed.
redis.del(key(type, account_id, "reblogs:#{reblogged_id}"))
end
end
def merge_into_timeline(from_account, into_account)
timeline_key = key(:home, into_account.id)
query = from_account.statuses.limit(FeedManager::MAX_ITEMS / 4)
if redis.zcard(timeline_key) >= FeedManager::MAX_ITEMS / 4
oldest_home_score = redis.zrange(timeline_key, 0, 0, with_scores: true)&.first&.last&.to_i || 0
query = query.where('id > ?', oldest_home_score)
end
query.each do |status|
next if status.direct_visibility? || filter?(:home, status, into_account)
add_to_feed(:home, into_account.id, status)
end
trim(:home, into_account.id)
end
def unmerge_from_timeline(from_account, into_account)
timeline_key = key(:home, into_account.id)
oldest_home_score = redis.zrange(timeline_key, 0, 0, with_scores: true)&.first&.last&.to_i || 0
from_account.statuses.select('id, reblog_of_id').where('id > ?', oldest_home_score).reorder(nil).find_each do |status|
remove_from_feed(:home, into_account.id, status)
end
end
def clear_from_timeline(account, target_account)
timeline_key = key(:home, account.id)
timeline_status_ids = redis.zrange(timeline_key, 0, -1)
target_statuses = Status.where(id: timeline_status_ids, account: target_account)
target_statuses.each do |status|
unpush_from_home(account, status)
end
end
def populate_feed(account)
added = 0
limit = FeedManager::MAX_ITEMS / 2
max_id = nil
loop do
statuses = Status.as_home_timeline(account)
.paginate_by_max_id(limit, max_id)
break if statuses.empty?
statuses.each do |status|
next if filter_from_home?(status, account)
added += 1 if add_to_feed(:home, account.id, status)
end
break unless added.zero?
max_id = statuses.last.id
end
end
private
def redis
Redis.current
end
def push_update_required?(timeline_id)
redis.exists("subscribed:#{timeline_id}")
end
def blocks_or_mutes?(receiver_id, account_ids, context)
Block.where(account_id: receiver_id, target_account_id: account_ids).any? ||
(context == :home ? Mute.where(account_id: receiver_id, target_account_id: account_ids).any? : Mute.where(account_id: receiver_id, target_account_id: account_ids, hide_notifications: true).any?)
end
def filter_from_home?(status, receiver_id)
return false if receiver_id == status.account_id
return true if status.reply? && (status.in_reply_to_id.nil? || status.in_reply_to_account_id.nil?)
check_for_blocks = status.mentions.pluck(:account_id)
check_for_blocks.concat([status.account_id])
check_for_blocks.concat([status.reblog.account_id]) if status.reblog?
return true if blocks_or_mutes?(receiver_id, check_for_blocks, :home)
if status.reply? && !status.in_reply_to_account_id.nil? # Filter out if it's a reply
should_filter = !Follow.where(account_id: receiver_id, target_account_id: status.in_reply_to_account_id).exists? # and I'm not following the person it's a reply to
should_filter &&= receiver_id != status.in_reply_to_account_id # and it's not a reply to me
should_filter &&= status.account_id != status.in_reply_to_account_id # and it's not a self-reply
return should_filter
elsif status.reblog? # Filter out a reblog
should_filter = Follow.where(account_id: receiver_id, target_account_id: status.account_id, show_reblogs: false).exists? # if the reblogger's reblogs are suppressed
should_filter ||= Block.where(account_id: status.reblog.account_id, target_account_id: receiver_id).exists? # or if the author of the reblogged status is blocking me
should_filter ||= AccountDomainBlock.where(account_id: receiver_id, domain: status.reblog.account.domain).exists? # or the author's domain is blocked
return should_filter
end
false
end
def filter_from_mentions?(status, receiver_id)
return true if receiver_id == status.account_id
# This filter is called from NotifyService, but already after the sender of
# the notification has been checked for mute/block. Therefore, it's not
# necessary to check the author of the toot for mute/block again
check_for_blocks = status.mentions.pluck(:account_id)
check_for_blocks.concat([status.in_reply_to_account]) if status.reply? && !status.in_reply_to_account_id.nil?
should_filter = blocks_or_mutes?(receiver_id, check_for_blocks, :mentions) # Filter if it's from someone I blocked, in reply to someone I blocked, or mentioning someone I blocked (or muted)
should_filter ||= (status.account.silenced? && !Follow.where(account_id: receiver_id, target_account_id: status.account_id).exists?) # of if the account is silenced and I'm not following them
should_filter
end
# Adds a status to an account's feed, returning true if a status was
# added, and false if it was not added to the feed. Note that this is
# an internal helper: callers must call trim or push updates if
# either action is appropriate.
def add_to_feed(timeline_type, account_id, status)
timeline_key = key(timeline_type, account_id)
reblog_key = key(timeline_type, account_id, 'reblogs')
if status.reblog?
# If the original status or a reblog of it is within
# REBLOG_FALLOFF statuses from the top, do not re-insert it into
# the feed
rank = redis.zrevrank(timeline_key, status.reblog_of_id)
return false if !rank.nil? && rank < FeedManager::REBLOG_FALLOFF
reblog_rank = redis.zrevrank(reblog_key, status.reblog_of_id)
if reblog_rank.nil?
# This is not something we've already seen reblogged, so we
# can just add it to the feed (and note that we're
# reblogging it).
redis.zadd(timeline_key, status.id, status.id)
redis.zadd(reblog_key, status.id, status.reblog_of_id)
else
# Another reblog of the same status was already in the
# REBLOG_FALLOFF most recent statuses, so we note that this
# is an "extra" reblog, by storing it in reblog_set_key.
reblog_set_key = key(timeline_type, account_id, "reblogs:#{status.reblog_of_id}")
redis.sadd(reblog_set_key, status.id)
return false
end
else
# A reblog may reach earlier than the original status because of the
# delay of the worker deliverying the original status, the late addition
# by merging timelines, and other reasons.
# If such a reblog already exists, just do not re-insert it into the feed.
rank = redis.zrevrank(reblog_key, status.id)
return false unless rank.nil?
redis.zadd(timeline_key, status.id, status.id)
end
true
end
# Removes an individual status from a feed, correctly handling cases
# with reblogs, and returning true if a status was removed. As with
# `add_to_feed`, this does not trigger push updates, so callers must
# do so if appropriate.
def remove_from_feed(timeline_type, account_id, status)
timeline_key = key(timeline_type, account_id)
if status.reblog?
# 1. If the reblogging status is not in the feed, stop.
status_rank = redis.zrevrank(timeline_key, status.id)
return false if status_rank.nil?
# 2. Remove reblog from set of this status's reblogs.
reblog_set_key = key(timeline_type, account_id, "reblogs:#{status.reblog_of_id}")
redis.srem(reblog_set_key, status.id)
# 3. Re-insert another reblog or original into the feed if one
# remains in the set. We could pick a random element, but this
# set should generally be small, and it seems ideal to show the
# oldest potential such reblog.
other_reblog = redis.smembers(reblog_set_key).map(&:to_i).sort.first
redis.zadd(timeline_key, other_reblog, other_reblog) if other_reblog
# 4. Remove the reblogging status from the feed (as normal)
# (outside conditional)
else
# If the original is getting deleted, no use for reblog references
redis.del(key(timeline_type, account_id, "reblogs:#{status.id}"))
end
redis.zrem(timeline_key, status.id)
end
end