Add emoji reaction cache

app/controllers/api/v1/accounts_controller.rb

@@ -8,13 +8,19 @@ class Api::V1::AccountsController < Api::BaseController
   before_action -> { doorkeeper_authorize! :write, :'write:accounts' }, only: [:create]
 
   before_action :require_user!, except: [:show, :create]
-  before_action :set_account, except: [:create]
+  before_action :set_account, except: [:index, :create]
   before_action :check_enabled_registrations, only: [:create]
 
   skip_before_action :require_authenticated_user!, only: :create
 
   override_rate_limit_headers :follow, family: :follows
 
+  def index
+    accounts = Account.where(id: account_ids)
+
+    render json: accounts, each_serializer: REST::AccountSerializer
+  end
+
   def show
     render json: @account, serializer: REST::AccountSerializer
   end
@@ -83,6 +89,10 @@ class Api::V1::AccountsController < Api::BaseController
     AccountRelationshipsPresenter.new([@account.id], current_user.account_id, **options)
   end
 
+  def account_ids
+    Array(params[:id]).map(&:to_i)
+  end
+
   def account_params
     params.permit(:username, :email, :password, :agreement, :locale, :reason)
   end

app/models/emoji_reaction.rb

@@ -18,6 +18,7 @@ class EmojiReaction < ApplicationRecord
   include Paginable
 
   after_commit :queue_publish
+  after_commit :refresh_status
 
   belongs_to :account
   belongs_to :status, inverse_of: :emoji_reactions 
@@ -37,4 +38,8 @@ class EmojiReaction < ApplicationRecord
   def queue_publish
     PublishEmojiReactionWorker.perform_async(status_id, name, custom_emoji_id) unless status.destroyed?
   end
+
+  def refresh_status
+    status.refresh_grouped_emoji_reactions! unless status.destroyed?
+  end
 end

app/models/status.rb

@@ -129,6 +129,7 @@ class Status < ApplicationRecord
 
   cache_associated :application,
                    :media_attachments,
+                   :emoji_reactions,
                    :conversation,
                    :status_stat,
                    :tags,
@@ -141,6 +142,7 @@ class Status < ApplicationRecord
                      :tags,
                      :preview_cards,
                      :media_attachments,
+                     :emoji_reactions,
                      :conversation,
                      :status_stat,
                      :preloadable_poll,
@@ -290,17 +292,25 @@ class Status < ApplicationRecord
     status_stat&.favourites_count || 0
   end
 
-  def grouped_reactions(account = nil)
-    records = begin
-      scope = emoji_reactions.group(:status_id, :name, :custom_emoji_id).order(Arel.sql('MIN(created_at) ASC'))
-      if account.nil?
-        scope.select('name, custom_emoji_id, count(*) as count, false as me')
-      else
-        scope.select(ActiveRecord::Base.sanitize_sql_array(["name, custom_emoji_id, count(*) as count, exists(select 1 from emoji_reactions r where r.account_id = :account_id and r.status_id = emoji_reactions.status_id and r.name = emoji_reactions.name and (r.custom_emoji_id IS NULL and emoji_reactions.custom_emoji_id IS NULL or r.custom_emoji_id = emoji_reactions.custom_emoji_id)) as me", account_id: account.id]))
+  def grouped_emoji_reactions(account = nil)
+    (Oj.load(status_stat&.emoji_reactions_cache || '', mode: :strict) || []).tap do |emoji_reactions|
+      if account.present?
+        emoji_reactions.each do |emoji_reaction|
+          emoji_reaction['me'] = emoji_reaction['account_ids'].include?(account.id.to_s)
         end
       end
-    ActiveRecord::Associations::Preloader.new.preload(records, :custom_emoji)
-    records
+    end
+  end
+
+  def generate_grouped_emoji_reactions
+    records = emoji_reactions.group(:status_id, :name, :custom_emoji_id).order(Arel.sql('MIN(created_at) ASC')).select('name, custom_emoji_id, count(*) as count, array_agg(account_id::text order by created_at) as account_ids')
+    ActiveModelSerializers::SerializableResource.new(records, each_serializer: REST::EmojiReactionSerializer, scope: nil, scope_name: :current_user).to_json
+  end
+
+  def refresh_grouped_emoji_reactions!
+    generate_grouped_emoji_reactions.tap do |emoji_reactions_cache|
+      update_status_stat!(emoji_reactions_cache: emoji_reactions_cache)
+    end
   end
 
   def increment_count!(key)

app/models/status_stat.rb

@@ -10,6 +10,7 @@
 #  favourites_count      :bigint(8)        default(0), not null
 #  created_at            :datetime         not null
 #  updated_at            :datetime         not null
+#  emoji_reactions_cache :string           default(""), not null
 #
 
 class StatusStat < ApplicationRecord

app/serializers/rest/emoji_reaction_serializer.rb

@@ -1,4 +1,42 @@
 # frozen_string_literal: true
 
-class REST::EmojiReactionSerializer < REST::ReactionSerializer
+class REST::EmojiReactionSerializer < ActiveModel::Serializer
+  include RoutingHelper
+  
+  attributes :name, :count
+
+  attribute :me, if: :current_user?
+  attribute :url, if: :custom_emoji?
+  attribute :static_url, if: :custom_emoji?
+  attribute :domain, if: :custom_emoji?
+  attribute :account_ids, if: :has_account_ids?
+
+  def count
+    object.respond_to?(:count) ? object.count : 0
   end
+
+  def current_user?
+    !current_user.nil?
+  end
+
+  def custom_emoji?
+    object.custom_emoji.present?
+  end
+
+  def has_account_ids?
+    object.respond_to?(:account_ids)
+  end
+
+  def url
+    full_asset_url(object.custom_emoji.image.url)
+  end
+
+  def static_url
+    full_asset_url(object.custom_emoji.image.url(:static))
+  end
+
+  def domain
+    object.custom_emoji.domain
+  end
+end
+  

app/serializers/rest/status_serializer.rb

@@ -4,7 +4,7 @@ class REST::StatusSerializer < ActiveModel::Serializer
   attributes :id, :created_at, :in_reply_to_id, :in_reply_to_account_id,
              :sensitive, :spoiler_text, :visibility, :language,
              :uri, :url, :replies_count, :reblogs_count,
-             :favourites_count
+             :favourites_count, :emoji_reactions
 
   attribute :favourited, if: :current_user?
   attribute :reblogged, if: :current_user?
@@ -30,7 +30,6 @@ class REST::StatusSerializer < ActiveModel::Serializer
   has_many :ordered_mentions, key: :mentions
   has_many :tags
   has_many :emojis, serializer: REST::CustomEmojiSerializer
-  has_many :emoji_reactions, serializer: REST::EmojiReactionSerializer
 
   has_one :preview_card, key: :card, serializer: REST::PreviewCardSerializer
   has_one :preloadable_poll, key: :poll, serializer: REST::PollSerializer
@@ -127,7 +126,7 @@ class REST::StatusSerializer < ActiveModel::Serializer
   end
 
   def emoji_reactions
-    object.grouped_reactions(current_user&.account)
+    object.grouped_emoji_reactions(current_user&.account)
   end
 
   def reblogged

config/routes.rb

@@ -465,7 +465,7 @@ Rails.application.routes.draw do
         resources :subscribing, only: :index, controller: 'subscribing_accounts'
       end
 
-      resources :accounts, only: [:create, :show] do
+      resources :accounts, only: [:index, :create, :show] do
         resources :statuses, only: :index, controller: 'accounts/statuses'
         resources :followers, only: :index, controller: 'accounts/follower_accounts'
         resources :following, only: :index, controller: 'accounts/following_accounts'

db/migrate/20210628130510_add_emoji_reactions_json_to_status_stat.rb

@@ -0,0 +1,15 @@
+require Rails.root.join('lib', 'mastodon', 'migration_helpers')
+
+class AddEmojiReactionsJsonToStatusStat < ActiveRecord::Migration[6.1]
+  include Mastodon::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  def up
+    safety_assured { add_column_with_default :status_stats, :emoji_reactions_cache, :string, default: '', allow_null: false }
+  end
+
+  def down
+    remove_column :status_stats, :emoji_reactions_cache
+  end
+end

db/schema.rb

@@ -941,6 +941,7 @@ ActiveRecord::Schema.define(version: 2021_08_08_071221) do
     t.bigint "favourites_count", default: 0, null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.string "emoji_reactions_cache", default: "", null: false
     t.index ["status_id"], name: "index_status_stats_on_status_id", unique: true
   end
 

lib/mastodon/cache_cli.rb

@@ -20,6 +20,7 @@ module Mastodon
 
     option :concurrency, type: :numeric, default: 5, aliases: [:c]
     option :verbose, type: :boolean, aliases: [:v]
+    option :reaction_only, type: :boolean
     desc 'recount TYPE', 'Update hard-cached counters'
     long_desc <<~LONG_DESC
       Update hard-cached counters of TYPE by counting referenced
@@ -41,11 +42,15 @@ module Mastodon
           account_stat.save if account_stat.changed?
         end
       when 'statuses'
-        processed, = parallelize_with_progress(Status.includes(:status_stat)) do |status|
+        statuses = Status.includes(:status_stat)
+        statuses = statuses.joins(:emoji_reactions).distinct if options[:reaction_only]
+
+        processed, = parallelize_with_progress(statuses) do |status|
           status_stat                       = status.status_stat
           status_stat.replies_count         = status.replies.where.not(visibility: :direct).count
           status_stat.reblogs_count         = status.reblogs.count
           status_stat.favourites_count      = status.favourites.count
+          status_stat.emoji_reactions_cache = status.generate_grouped_emoji_reactions
 
           status_stat.save if status_stat.changed?
         end