From 7f21744661069facc88c85f1bd53972c47a0401e Mon Sep 17 00:00:00 2001
From: multiple creatures <dev@multiple-creature.party>
Date: Mon, 18 Nov 2019 08:26:22 -0600
Subject: When a post is delayed or updated, remove the old version from local
 timelines before delivering the new verison.

---
 .../remove_from_local_timelines_service.rb         | 84 ++++++++++++++++++++++
 app/workers/post_status_worker.rb                  |  2 +
 2 files changed, 86 insertions(+)
 create mode 100644 app/services/remove_from_local_timelines_service.rb

(limited to 'app')

diff --git a/app/services/remove_from_local_timelines_service.rb b/app/services/remove_from_local_timelines_service.rb
new file mode 100644
index 000000000..4c9c6bb51
--- /dev/null
+++ b/app/services/remove_from_local_timelines_service.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+class RemoveFromLocalTimelinesService < BaseService
+  include Redisable
+
+  def call(status)
+    @payload      = Oj.dump(event: :delete, payload: status.id.to_s)
+    @status       = status
+    @account      = status.account
+    @tags         = status.tags.pluck(:name).to_a
+    @mentions     = status.active_mentions.includes(:account).to_a
+    @reblogs      = status.reblogs.includes(:account).to_a
+
+    RedisLock.acquire(lock_options) do |lock|
+      if lock.acquired?
+        remove_from_self if status.account.local?
+        remove_from_followers
+        remove_from_lists
+        remove_from_affected
+        remove_from_hashtags
+        remove_from_public
+        remove_from_media if status.media_attachments.any?
+        remove_from_direct if status.direct_visibility?
+      else
+        raise Mastodon::RaceConditionError
+      end
+    end
+  end
+
+  private
+
+  def remove_from_self
+    FeedManager.instance.unpush_from_home(@account, @status)
+  end
+
+  def remove_from_followers
+    @account.followers_for_local_distribution.reorder(nil).find_each do |follower|
+      FeedManager.instance.unpush_from_home(follower, @status)
+    end
+  end
+
+  def remove_from_lists
+    @account.lists_for_local_distribution.select(:id, :account_id).reorder(nil).find_each do |list|
+      FeedManager.instance.unpush_from_list(list, @status)
+    end
+  end
+
+  def remove_from_affected
+    @mentions.map(&:account).select(&:local?).each do |account|
+      redis.publish("timeline:#{account.id}", @payload)
+    end
+  end
+
+  def remove_from_hashtags
+    return unless @status.distributable?
+    @tags.each do |hashtag|
+      redis.publish("timeline:hashtag:#{hashtag}", @payload)
+      redis.publish("timeline:hashtag:#{hashtag}:local", @payload) if @status.local?
+    end
+  end
+
+  def remove_from_public
+    return unless @status.distributable?
+    redis.publish('timeline:public', @payload)
+    redis.publish('timeline:public:local', @payload) if @status.local?
+  end
+
+  def remove_from_media
+    return unless @status.distributable?
+    redis.publish('timeline:public:media', @payload)
+    redis.publish('timeline:public:local:media', @payload) if @status.local?
+  end
+
+  def remove_from_direct
+    @mentions.each do |mention|
+      Redis.current.publish("timeline:direct:#{mention.account.id}", @payload) if mention.account.local?
+    end
+    Redis.current.publish("timeline:direct:#{@account.id}", @payload) if @account.local?
+  end
+
+  def lock_options
+    { redis: Redis.current, key: "distribute:#{@status.id}" }
+  end
+end
diff --git a/app/workers/post_status_worker.rb b/app/workers/post_status_worker.rb
index 7b44c9a54..78e824964 100644
--- a/app/workers/post_status_worker.rb
+++ b/app/workers/post_status_worker.rb
@@ -9,6 +9,8 @@ class PostStatusWorker
     status = Status.find(status_id)
     return false if status.destroyed?
 
+    RemoveFromLocalTimelinesService.new.call(status)
+
     status.visibility = options[:visibility] if options[:visibility]
     status.local_only = options[:local_only] if options[:local_only]
     status.reject_replies = options[:reject_replies] if options[:reject_replies]
-- 
cgit