about summary refs log tree commit diff
path: root/app/lib/feed_manager.rb
blob: 98d5105f2d8d4d1db34803bed4c7c604eaea030a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
# frozen_string_literal: true

require 'singleton'

# rubocop:disable Metrics/ClassLength
class FeedManager
  include Singleton
  include Redisable

  MAX_ITEMS = 1000

  # Must be <= MAX_ITEMS or the tracking sets will grow forever
  REBLOG_FALLOFF = 50

  def with_active_accounts(&block)
    Account.joins(:user).where('users.current_sign_in_at > ?', User::ACTIVE_DURATION.ago).find_each(&block)
  end

  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 [:home, :list].include?(timeline_type)
      filter_from_home?(status, receiver_id, build_crutches(receiver_id, [status]), filter_options_for(receiver_id))
    elsif timeline_type == :mentions
      filter_from_mentions?(status, receiver_id)
    elsif timeline_type == :direct
      filter_from_direct?(status, receiver_id)
    else
      false
    end
  end

  def push_to_home(account, status)
    return false unless add_to_feed(:home, account.id, status, account.user&.aggregates_reblogs?)

    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, account.user&.aggregates_reblogs?)

    redis.publish("timeline:#{account.id}", Oj.dump(event: :delete, payload: status.id.to_s))
    true
  end

  def push_to_list(list, status)
    return false if status.reblog?

    if status.reply? && status.in_reply_to_account_id != status.account_id
      should_filter = status.in_reply_to_account_id != list.account_id
      should_filter &&= status.account_id == list.account_id
      should_filter &&= !list.show_all_replies?
      should_filter &&= !(list.show_list_replies? && ListAccount.where(list_id: list.id, account_id: status.in_reply_to_account_id).exists?)
      return false if should_filter
    end

    return false unless add_to_feed(:list, list.id, status, list.account.user&.aggregates_reblogs?)

    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, list.account.user&.aggregates_reblogs?)

    redis.publish("timeline:list:#{list.id}", Oj.dump(event: :delete, payload: status.id.to_s))
    true
  end

  def push_to_direct(account, status)
    return false unless add_to_feed(:direct, account.id, status)

    trim(:direct, account.id)
    PushUpdateWorker.perform_async(account.id, status.id, "timeline:direct:#{account.id}")
    true
  end

  def unpush_from_direct(account, status)
    return false unless remove_from_feed(:direct, account.id, status)

    redis.publish("timeline:direct:#{account.id}", Oj.dump(event: :delete, payload: status.id.to_s))
  end

  def unpush_status(account, status)
    return if account.blank? || status.blank?

    unpush_from_home(account, status)
    unpush_from_direct(account, status) if status.direct_visibility?

    account.lists_for_local_distribution.select(:id, :account_id).each do |list|
      unpush_from_list(list, status)
    end
  end

  def unpush_conversation(account, conversation)
    return if account.blank? || conversation.blank?

    conversation.statuses.reorder(nil).find_each do |status|
      unpush_status(account, status)
    end
  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))

    # 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)
    aggregate    = into_account.user&.aggregates_reblogs?
    query        = from_account.statuses.where(visibility: [:public, :unlisted, :private]).includes(:preloadable_poll, reblog: :account).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
      query = query.where('id > ?', oldest_home_score)
    end

    statuses = query.to_a
    crutches = build_crutches(into_account.id, statuses)
    filter_options = filter_options_for(into_account.id)

    statuses.each do |status|
      next if filter_from_home?(status, into_account.id, crutches, filter_options)

      add_to_feed(:home, into_account.id, status, aggregate)
    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, into_account.user&.aggregates_reblogs?)
    end
  end

  def clear_from_timeline(account, target_account)
    # Clear from timeline all statuses from or mentionning target_account
    timeline_key        = key(:home, account.id)
    timeline_status_ids = redis.zrange(timeline_key, 0, -1)
    statuses            = Status.where(id: timeline_status_ids).select(:id, :reblog_of_id, :account_id).to_a
    reblogged_ids       = Status.where(id: statuses.map(&:reblog_of_id).compact, account: target_account).pluck(:id)
    with_mentions_ids   = Mention.active.where(status_id: statuses.flat_map { |s| [s.id, s.reblog_of_id] }.compact, account: target_account).pluck(:status_id)
    target_statuses     = statuses.filter do |status|
      status.account_id == target_account.id || reblogged_ids.include?(status.reblog_of_id) || with_mentions_ids.include?(status.id) || with_mentions_ids.include?(status.reblog_of_id)
    end

    target_statuses.each do |status|
      unpush_from_home(account, status)
    end
  end

  def populate_feed(account)
    limit        = FeedManager::MAX_ITEMS / 2
    aggregate    = account.user&.aggregates_reblogs?
    timeline_key = key(:home, account.id)

    account.statuses.where.not(visibility: :direct).limit(limit).each do |status|
      add_to_feed(:home, account.id, status, aggregate)
    end

    account.following.includes(:account_stat).find_each do |target_account|
      if redis.zcard(timeline_key) >= limit
        oldest_home_score = redis.zrange(timeline_key, 0, 0, with_scores: true).first.last.to_i
        last_status_score = Mastodon::Snowflake.id_at(account.last_status_at)

        # If the feed is full and this account has not posted more recently
        # than the last item on the feed, then we can skip the whole account
        # because none of its statuses would stay on the feed anyway
        next if last_status_score < oldest_home_score
      end

      statuses = target_account.statuses.published.without_replies.where(visibility: [:public, :unlisted, :private]).includes(:preloadable_poll, reblog: :account).limit(limit)
      crutches = build_crutches(account.id, statuses)
      filter_options = filter_options_for(account.id)

      statuses.each do |status|
        next if filter_from_home?(status, account.id, crutches, filter_options)

        add_to_feed(:home, account.id, status, aggregate)
      end

      trim(:home, account.id)
    end
  end

  def populate_direct_feed(account)
    added  = 0
    limit  = FeedManager::MAX_ITEMS / 2
    max_id = nil

    loop do
      statuses = Status.as_direct_timeline(account, limit, max_id)

      break if statuses.empty?

      statuses.each do |status|
        next if filter_from_direct?(status, account)

        added += 1 if add_to_feed(:direct, account.id, status)
      end

      break unless added.zero?

      max_id = statuses.last.id
    end
  end

  private

  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, crutches, filter_options)
    conversation = status.conversation
    reblog_conversation = status.reblog&.conversation

    return false if receiver_id == status.account_id
    return true  unless status.published?
    return true  if crutches[:hiding_thread][status.conversation_id] if conversation.present?
    return true  if status.reply? && (status.in_reply_to_id.nil? || status.in_reply_to_account_id.nil?)
    return true  if phrase_filtered?(status, receiver_id, :home)

    check_for_blocks = crutches[:active_mentions][status.id] || []
    check_for_blocks.concat([status.account_id, conversation&.account_id])
    check_for_blocks.concat([status.in_reply_to_account_id]) if status.reply?

    if status.reblog?
      check_for_blocks.concat([status.reblog.account_id, reblog_conversation&.account_id])
      check_for_blocks.concat(crutches[:active_mentions][status.reblog_of_id] || [])
      check_for_blocks.concat([status.reblog.in_reply_to_account_id]) if status.reblog.reply?
    end

    check_for_blocks.uniq!
    check_for_blocks.compact!
    return true if check_for_blocks.any? { |target_account_id| crutches[:blocking][target_account_id] || crutches[:muting][target_account_id] }

    # Filter if...
    if status.reply? # ...it's a reply and...
      # ...you're not following the author...
      should_filter   = !crutches[:following][status.in_reply_to_account_id]
      # (optional) ...or the owner(s) of the thread...
      should_filter ||= !crutches[:following][conversation.account_id] if filter_options[:to_unknown] && conversation&.account_id.present?
      # ...and the author isn't replying to a post you wrote...
      should_filter &&= receiver_id != status.in_reply_to_account_id
      # ...and the author isn't mentioning you.
      should_filter &&= !crutches[:active_mentions][receiver_id]

      return !!should_filter
    elsif status.reblog? # ...it's a boost and...
      should_filter = false

      # ...it's a reply...
      if status.reblog.reply? && !status.reblog.in_reply_to_account_id.nil?
        # ...and you don't follow the author if:
        # - you're filtering replies to parent authors you don't follow
        # - they're silenced on this server
        should_filter ||= !crutches[:following][status.reblog.in_reply_to_account_id] if filter_options[:to_unknown] || status.reblog.in_reply_to_account.silenced?
        # - you're filtering replies to threads whose owners you don't follow
        should_filter ||= !crutches[:following][reblog_conversation.account_id] if filter_options[:to_unknown] && reblog_conversation&.account_id.present?
        # ...or you're blocking their domain...
        should_filter ||= crutches[:domain_blocking][status.reblog.thread.account.domain] if status.reblog.thread.present?
      end

      # ...or it's a post from a thread's trunk and you don't follow the author if:
      # - you're filtering boosts of authors you don't follow
      # - they're silenced on this server
      should_filter ||= !crutches[:following][status.reblog.account_id] if filter_options[:from_unknown] || status.reblog.account.silenced?

      # ..or you're hiding boosts from them...
      should_filter ||= crutches[:hiding_reblogs][status.account_id]
      # ...or they're blocking you...
      should_filter ||= crutches[:blocked_by][status.reblog.account_id]
      # ...or you're blocking their domain...
      should_filter ||= crutches[:domain_blocking][status.reblog.account.domain]

      return !!should_filter
    end

    crutches[:following][status.account_id]
  end

  def filter_from_mentions?(status, receiver_id)
    return true if receiver_id == status.account_id
    return true if phrase_filtered?(status, receiver_id, :notifications)

    # 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.active_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)
    should_filter ||= (status.account.silenced? && !relationship_exists?(receiver_id, status.account_id))

    should_filter
  end

  def relationship_exists?(account_id, target_account_id)
    Follow.where(account_id: account_id, target_account_id: target_account_id)
          .or(Follow.where(account_id: target_account_id, target_account_id: account_id))
          .exists?
  end

  def filter_from_direct?(status, receiver_id)
    return false if receiver_id == status.account_id

    filter_from_mentions?(status, receiver_id)
  end

  def phrase_filtered?(status, receiver_id, context)
    active_filters = Rails.cache.fetch("filters:#{receiver_id}") { CustomFilter.where(account_id: receiver_id).active_irreversible.to_a }.to_a

    active_filters.select! { |filter| filter.context.include?(context.to_s) && !filter.expired? }

    active_filters.map! do |filter|
      if filter.whole_word
        sb = filter.phrase =~ /\A[[:word:]]/ ? '\b' : ''
        eb = filter.phrase =~ /[[:word:]]\z/ ? '\b' : ''

        /(?mix:#{sb}#{Regexp.escape(filter.phrase)}#{eb})/
      else
        /#{Regexp.escape(filter.phrase)}/i
      end
    end

    return false if active_filters.empty?

    combined_regex = active_filters.reduce { |memo, obj| Regexp.union(memo, obj) }
    status         = status.reblog if status.reblog?

    combined_text = [
      Formatter.instance.plaintext(status),
      status.spoiler_text,
      status.preloadable_poll ? status.preloadable_poll.options.join("\n\n") : nil,
      status.media_attachments.map(&:description).join("\n\n"),
    ].compact.join("\n\n")

    !combined_regex.match(combined_text).nil?
  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, aggregate_reblogs = true)
    timeline_key = key(timeline_type, account_id)
    reblog_key   = key(timeline_type, account_id, 'reblogs')

    if status.reblog? && (aggregate_reblogs.nil? || aggregate_reblogs)
      # 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, aggregate_reblogs = true)
    timeline_key = key(timeline_type, account_id)
    reblog_key   = key(timeline_type, account_id, 'reblogs')

    if status.reblog? && (aggregate_reblogs.nil? || aggregate_reblogs)
      # 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)
      redis.zrem(reblog_key, status.reblog_of_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).min

      redis.zadd(timeline_key, other_reblog, other_reblog) if other_reblog
      redis.zadd(reblog_key, other_reblog, status.reblog_of_id) 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}"))
      redis.zrem(reblog_key, status.id)
    end

    redis.zrem(timeline_key, status.id)
  end

  def filter_options_for(receiver_id)
    Rails.cache.fetch("filter_settings:#{receiver_id}", expires_in: 1.month) do
      return {} if (settings = User.find_by(account_id: receiver_id)&.settings).blank?

      {
        to_unknown: settings.filter_to_unknown,
        from_unknown: settings.filter_from_unknown,
      }
    end
  end

  def build_crutches(receiver_id, statuses)
    crutches = {}

    crutches[:active_mentions] = Mention.active.where(status_id: statuses.flat_map { |s| [s.id, s.reblog_of_id] }.compact).pluck(:status_id, :account_id).each_with_object({}) { |(id, account_id), mapping| (mapping[id] ||= []).push(account_id) }

    check_for_blocks = statuses.flat_map do |s|
      arr = crutches[:active_mentions][s.id] || []
      arr.concat([s.account_id])

      if s.reblog?
        arr.concat([s.reblog.account_id])
        arr.concat(crutches[:active_mentions][s.reblog_of_id] || [])
      end

      arr
    end

    crutches[:following]       = Follow.where(account_id: receiver_id, target_account_id: statuses.map(&:in_reply_to_account_id).compact).pluck(:target_account_id).each_with_object({}) { |id, mapping| mapping[id] = true }
    crutches[:hiding_reblogs]  = Follow.where(account_id: receiver_id, target_account_id: statuses.map { |s| s.account_id if s.reblog? }.compact, show_reblogs: false).pluck(:target_account_id).each_with_object({}) { |id, mapping| mapping[id] = true }
    crutches[:blocking]        = Block.where(account_id: receiver_id, target_account_id: check_for_blocks).pluck(:target_account_id).each_with_object({}) { |id, mapping| mapping[id] = true }
    crutches[:muting]          = Mute.where(account_id: receiver_id, target_account_id: check_for_blocks).pluck(:target_account_id).each_with_object({}) { |id, mapping| mapping[id] = true }
    crutches[:domain_blocking] = AccountDomainBlock.where(account_id: receiver_id, domain: statuses.map { |s| s.reblog&.account&.domain }.compact).pluck(:domain).each_with_object({}) { |domain, mapping| mapping[domain] = true }
    crutches[:blocked_by]      = Block.where(target_account_id: receiver_id, account_id: statuses.map { |s| s.reblog&.account_id }.compact).pluck(:account_id).each_with_object({}) { |id, mapping| mapping[id] = true }
    crutches[:hiding_thread]   = ConversationMute.where(account_id: receiver_id, conversation_id: statuses.map(&:conversation_id).compact, hidden: true).pluck(:conversation_id).each_with_object({}) { |id, mapping| mapping[id] = true }

    crutches
  end
end
# rubocop:enable Metrics/ClassLength