Refactor controllers for statuses, accounts, and more (#11249)

41 files changed, 299 insertions, 289 deletions

diff --git a/app/controllers/about_controller.rb b/app/controllers/about_controller.rb
index 52a51fd62..761c7f5cd 100644
--- a/app/controllers/about_controller.rb
+++ b/app/controllers/about_controller.rb
@@ -3,11 +3,11 @@
 class AboutController < ApplicationController
   layout 'public'
 
-  before_action :set_instance_presenter, only: [:show, :more, :terms]
+  before_action :set_body_classes, only: :show
+  before_action :set_instance_presenter
+  before_action :set_expires_in
 
-  def show
-    @hide_navbar = true
-  end
+  def show; end
 
   def more; end
 
@@ -27,4 +27,12 @@ class AboutController < ApplicationController
   def set_instance_presenter
     @instance_presenter = InstancePresenter.new
   end
+
+  def set_body_classes
+    @hide_navbar = true
+  end
+
+  def set_expires_in
+    expires_in 0, public: true
+  end
 end
diff --git a/app/controllers/accounts_controller.rb b/app/controllers/accounts_controller.rb
index 065707378..3184a73cb 100644
--- a/app/controllers/accounts_controller.rb
+++ b/app/controllers/accounts_controller.rb
@@ -6,13 +6,13 @@ class AccountsController < ApplicationController
   include AccountControllerConcern
 
   before_action :set_cache_headers
+  before_action :set_body_classes
 
   def show
     respond_to do |format|
       format.html do
-        mark_cacheable! unless user_signed_in?
+        expires_in 0, public: true unless user_signed_in?
 
-        @body_classes      = 'with-modals'
         @pinned_statuses   = []
         @endorsed_accounts = @account.endorsed_accounts.to_a.sample(4)
 
@@ -32,22 +32,25 @@ class AccountsController < ApplicationController
       end
 
       format.rss do
-        mark_cacheable!
+        expires_in 0, public: true
 
         @statuses = cache_collection(default_statuses.without_reblogs.without_replies.limit(PAGE_SIZE), Status)
         render xml: RSS::AccountSerializer.render(@account, @statuses)
       end
 
       format.json do
-        render_cached_json(['activitypub', 'actor', @account], content_type: 'application/activity+json') do
-          ActiveModelSerializers::SerializableResource.new(@account, serializer: ActivityPub::ActorSerializer, adapter: ActivityPub::Adapter)
-        end
+        expires_in 3.minutes, public: true
+        render json: @account, content_type: 'application/activity+json', serializer: ActivityPub::ActorSerializer, adapter: ActivityPub::Adapter
       end
     end
   end
 
   private
 
+  def set_body_classes
+    @body_classes = 'with-modals'
+  end
+
   def show_pinned_statuses?
     [replies_requested?, media_requested?, tag_requested?, params[:max_id].present?, params[:min_id].present?].none?
   end
diff --git a/app/controllers/activitypub/collections_controller.rb b/app/controllers/activitypub/collections_controller.rb
index 012c3c538..dd2f111b0 100644
--- a/app/controllers/activitypub/collections_controller.rb
+++ b/app/controllers/activitypub/collections_controller.rb
@@ -2,29 +2,19 @@
 
 class ActivityPub::CollectionsController < Api::BaseController
   include SignatureVerification
+  include AccountOwnedConcern
 
-  before_action :set_account
   before_action :set_size
   before_action :set_statuses
   before_action :set_cache_headers
 
   def show
-    render_cached_json(['activitypub', 'collection', @account, params[:id]], content_type: 'application/activity+json') do
-      ActiveModelSerializers::SerializableResource.new(
-        collection_presenter,
-        serializer: ActivityPub::CollectionSerializer,
-        adapter: ActivityPub::Adapter,
-        skip_activities: true
-      )
-    end
+    expires_in 3.minutes, public: true
+    render json: collection_presenter, content_type: 'application/activity+json', serializer: ActivityPub::CollectionSerializer, adapter: ActivityPub::Adapter, skip_activities: true
   end
 
   private
 
-  def set_account
-    @account = Account.find_local!(params[:account_username])
-  end
-
   def set_statuses
     @statuses = scope_for_collection
     @statuses = cache_collection(@statuses, Status)
diff --git a/app/controllers/activitypub/inboxes_controller.rb b/app/controllers/activitypub/inboxes_controller.rb
index e2cd8eaed..9be0676e1 100644
--- a/app/controllers/activitypub/inboxes_controller.rb
+++ b/app/controllers/activitypub/inboxes_controller.rb
@@ -3,8 +3,7 @@
 class ActivityPub::InboxesController < Api::BaseController
   include SignatureVerification
   include JsonLdHelper
-
-  before_action :set_account
+  include AccountOwnedConcern
 
   def create
     if unknown_deleted_account?
@@ -27,8 +26,8 @@ class ActivityPub::InboxesController < Api::BaseController
     false
   end
 
-  def set_account
-    @account = Account.find_local!(params[:account_username]) if params[:account_username]
+  def account_required?
+    params[:account_username].present?
   end
 
   def body
diff --git a/app/controllers/activitypub/outboxes_controller.rb b/app/controllers/activitypub/outboxes_controller.rb
index 5147afbf7..4c0b769f0 100644
--- a/app/controllers/activitypub/outboxes_controller.rb
+++ b/app/controllers/activitypub/outboxes_controller.rb
@@ -4,8 +4,8 @@ class ActivityPub::OutboxesController < Api::BaseController
   LIMIT = 20
 
   include SignatureVerification
+  include AccountOwnedConcern
 
-  before_action :set_account
   before_action :set_statuses
   before_action :set_cache_headers
 
@@ -17,10 +17,6 @@ class ActivityPub::OutboxesController < Api::BaseController
 
   private
 
-  def set_account
-    @account = Account.find_local!(params[:account_username])
-  end
-
   def outbox_presenter
     if page_requested?
       ActivityPub::CollectionPresenter.new(
diff --git a/app/controllers/activitypub/replies_controller.rb b/app/controllers/activitypub/replies_controller.rb
new file mode 100644
index 000000000..99b7b310f
--- /dev/null
+++ b/app/controllers/activitypub/replies_controller.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+class ActivityPub::RepliesController < Api::BaseController
+  include SignatureAuthentication
+  include Authorization
+  include AccountOwnedConcern
+
+  DESCENDANTS_LIMIT = 60
+
+  before_action :set_status
+  before_action :set_cache_headers
+  before_action :set_replies
+
+  def index
+    render json: replies_collection_presenter, serializer: ActivityPub::CollectionSerializer, adapter: ActivityPub::Adapter, content_type: 'application/activity+json', skip_activities: true
+  end
+
+  private
+
+  def set_status
+    @status = @account.statuses.find(params[:status_id])
+    authorize @status, :show?
+  rescue Mastodon::NotPermittedError
+    raise ActiveRecord::RecordNotFound
+  end
+
+  def set_replies
+    @replies = page_params[:other_accounts] ? Status.where.not(account_id: @account.id) : @account.statuses
+    @replies = @replies.where(in_reply_to_id: @status.id, visibility: [:public, :unlisted])
+    @replies = @replies.paginate_by_min_id(DESCENDANTS_LIMIT, params[:min_id])
+  end
+
+  def replies_collection_presenter
+    page = ActivityPub::CollectionPresenter.new(
+      id: account_status_replies_url(@account, @status, page_params),
+      type: :unordered,
+      part_of: account_status_replies_url(@account, @status),
+      next: next_page,
+      items: @replies.map { |status| status.local ? status : status.id }
+    )
+
+    return page if page_requested?
+
+    ActivityPub::CollectionPresenter.new(
+      id: account_status_replies_url(@account, @status),
+      type: :unordered,
+      first: page
+    )
+  end
+
+  def page_requested?
+    params[:page] == 'true'
+  end
+
+  def next_page
+    account_status_replies_url(
+      @account,
+      @status,
+      page: true,
+      min_id: @replies&.last&.id,
+      other_accounts: !(@replies&.last&.account_id == @account.id && @replies.size == DESCENDANTS_LIMIT)
+    )
+  end
+
+  def page_params
+    params_slice(:other_accounts, :min_id).merge(page: true)
+  end
+end
diff --git a/app/controllers/api/proofs_controller.rb b/app/controllers/api/proofs_controller.rb
index a84ad2014..a98599eee 100644
--- a/app/controllers/api/proofs_controller.rb
+++ b/app/controllers/api/proofs_controller.rb
@@ -1,10 +1,9 @@
 # frozen_string_literal: true
 
 class Api::ProofsController < Api::BaseController
-  before_action :set_account
+  include AccountOwnedConcern
+
   before_action :set_provider
-  before_action :check_account_approval
-  before_action :check_account_suspension
 
   def index
     render json: @account, serializer: @provider.serializer_class
@@ -16,15 +15,7 @@ class Api::ProofsController < Api::BaseController
     @provider = ProofProvider.find(params[:provider]) || raise(ActiveRecord::RecordNotFound)
   end
 
-  def set_account
-    @account = Account.find_local!(params[:username])
-  end
-
-  def check_account_approval
-    not_found if @account.user_pending?
-  end
-
-  def check_account_suspension
-    gone if @account.suspended?
+  def username_param
+    params[:username]
   end
 end
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index bd8000db0..cc8b8e4da 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -154,8 +154,4 @@ class ApplicationController < ActionController::Base
   def set_cache_headers
     response.headers['Vary'] = 'Accept'
   end
-
-  def mark_cacheable!
-    expires_in 0, public: true
-  end
 end
diff --git a/app/controllers/concerns/account_controller_concern.rb b/app/controllers/concerns/account_controller_concern.rb
index 1c422096c..287a930da 100644
--- a/app/controllers/concerns/account_controller_concern.rb
+++ b/app/controllers/concerns/account_controller_concern.rb
@@ -3,24 +3,19 @@
 module AccountControllerConcern
   extend ActiveSupport::Concern
 
+  include AccountOwnedConcern
+
   FOLLOW_PER_PAGE = 12
 
   included do
     layout 'public'
 
-    before_action :set_account
-    before_action :check_account_approval
-    before_action :check_account_suspension
     before_action :set_instance_presenter
     before_action :set_link_headers
   end
 
   private
 
-  def set_account
-    @account = Account.find_local!(username_param)
-  end
-
   def set_instance_presenter
     @instance_presenter = InstancePresenter.new
   end
@@ -29,27 +24,15 @@ module AccountControllerConcern
     response.headers['Link'] = LinkHeader.new(
       [
         webfinger_account_link,
-        atom_account_url_link,
         actor_url_link,
       ]
     )
   end
 
-  def username_param
-    params[:account_username]
-  end
-
   def webfinger_account_link
     [
       webfinger_account_url,
-      [%w(rel lrdd), %w(type application/xrd+xml)],
-    ]
-  end
-
-  def atom_account_url_link
-    [
-      account_url(@account, format: 'atom'),
-      [%w(rel alternate), %w(type application/atom+xml)],
+      [%w(rel lrdd), %w(type application/jrd+json)],
     ]
   end
 
@@ -63,15 +46,4 @@ module AccountControllerConcern
   def webfinger_account_url
     webfinger_url(resource: @account.to_webfinger_s)
   end
-
-  def check_account_approval
-    not_found if @account.user_pending?
-  end
-
-  def check_account_suspension
-    if @account.suspended?
-      expires_in(3.minutes, public: true)
-      gone
-    end
-  end
 end
diff --git a/app/controllers/concerns/account_owned_concern.rb b/app/controllers/concerns/account_owned_concern.rb
new file mode 100644
index 000000000..99c240fe9
--- /dev/null
+++ b/app/controllers/concerns/account_owned_concern.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module AccountOwnedConcern
+  extend ActiveSupport::Concern
+
+  included do
+    before_action :set_account, if: :account_required?
+    before_action :check_account_approval, if: :account_required?
+    before_action :check_account_suspension, if: :account_required?
+  end
+
+  private
+
+  def account_required?
+    true
+  end
+
+  def set_account
+    @account = Account.find_local!(username_param)
+  end
+
+  def username_param
+    params[:account_username]
+  end
+
+  def check_account_approval
+    not_found if @account.local? && @account.user_pending?
+  end
+
+  def check_account_suspension
+    expires_in(3.minutes, public: true) && gone if @account.suspended?
+  end
+end
diff --git a/app/controllers/concerns/status_controller_concern.rb b/app/controllers/concerns/status_controller_concern.rb
new file mode 100644
index 000000000..62a7cf508
--- /dev/null
+++ b/app/controllers/concerns/status_controller_concern.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+module StatusControllerConcern
+  extend ActiveSupport::Concern
+
+  ANCESTORS_LIMIT         = 40
+  DESCENDANTS_LIMIT       = 60
+  DESCENDANTS_DEPTH_LIMIT = 20
+
+  def create_descendant_thread(starting_depth, statuses)
+    depth = starting_depth + statuses.size
+
+    if depth < DESCENDANTS_DEPTH_LIMIT
+      {
+        statuses: statuses,
+        starting_depth: starting_depth,
+      }
+    else
+      next_status = statuses.pop
+
+      {
+        statuses: statuses,
+        starting_depth: starting_depth,
+        next_status: next_status,
+      }
+    end
+  end
+
+  def set_ancestors
+    @ancestors     = @status.reply? ? cache_collection(@status.ancestors(ANCESTORS_LIMIT, current_account), Status) : []
+    @next_ancestor = @ancestors.size < ANCESTORS_LIMIT ? nil : @ancestors.shift
+  end
+
+  def set_descendants
+    @max_descendant_thread_id   = params[:max_descendant_thread_id]&.to_i
+    @since_descendant_thread_id = params[:since_descendant_thread_id]&.to_i
+
+    descendants = cache_collection(
+      @status.descendants(
+        DESCENDANTS_LIMIT,
+        current_account,
+        @max_descendant_thread_id,
+        @since_descendant_thread_id,
+        DESCENDANTS_DEPTH_LIMIT
+      ),
+      Status
+    )
+
+    @descendant_threads = []
+
+    if descendants.present?
+      statuses       = [descendants.first]
+      starting_depth = 0
+
+      descendants.drop(1).each_with_index do |descendant, index|
+        if descendants[index].id == descendant.in_reply_to_id
+          statuses << descendant
+        else
+          @descendant_threads << create_descendant_thread(starting_depth, statuses)
+
+          # The thread is broken, assume it's a reply to the root status
+          starting_depth = 0
+
+          # ... unless we can find its ancestor in one of the already-processed threads
+          @descendant_threads.reverse_each do |descendant_thread|
+            statuses = descendant_thread[:statuses]
+
+            index = statuses.find_index do |thread_status|
+              thread_status.id == descendant.in_reply_to_id
+            end
+
+            if index.present?
+              starting_depth = descendant_thread[:starting_depth] + index + 1
+              break
+            end
+          end
+
+          statuses = [descendant]
+        end
+      end
+
+      @descendant_threads << create_descendant_thread(starting_depth, statuses)
+    end
+
+    @max_descendant_thread_id = @descendant_threads.pop[:statuses].first.id if descendants.size >= DESCENDANTS_LIMIT
+  end
+end
diff --git a/app/controllers/custom_css_controller.rb b/app/controllers/custom_css_controller.rb
index 6e80feaf8..7f4dcfcfe 100644
--- a/app/controllers/custom_css_controller.rb
+++ b/app/controllers/custom_css_controller.rb
@@ -6,6 +6,7 @@ class CustomCssController < ApplicationController
   before_action :set_cache_headers
 
   def show
+    expires 3.minutes, public: true
     render plain: Setting.custom_css || '', content_type: 'text/css'
   end
 end
diff --git a/app/controllers/emojis_controller.rb b/app/controllers/emojis_controller.rb
index 3feb08132..fe4c19cad 100644
--- a/app/controllers/emojis_controller.rb
+++ b/app/controllers/emojis_controller.rb
@@ -7,9 +7,8 @@ class EmojisController < ApplicationController
   def show
     respond_to do |format|
       format.json do
-        render_cached_json(['activitypub', 'emoji', @emoji], content_type: 'application/activity+json') do
-          ActiveModelSerializers::SerializableResource.new(@emoji, serializer: ActivityPub::EmojiSerializer, adapter: ActivityPub::Adapter)
-        end
+        expires_in 3.minutes, public: true
+        render json: @emoji, content_type: 'application/activity+json', serializer: ActivityPub::EmojiSerializer, adapter: ActivityPub::Adapter
       end
     end
   end
diff --git a/app/controllers/follower_accounts_controller.rb b/app/controllers/follower_accounts_controller.rb
index 415abe10c..8baa64490 100644
--- a/app/controllers/follower_accounts_controller.rb
+++ b/app/controllers/follower_accounts_controller.rb
@@ -8,7 +8,7 @@ class FollowerAccountsController < ApplicationController
   def index
     respond_to do |format|
       format.html do
-        mark_cacheable! unless user_signed_in?
+        expires_in 0, public: true unless user_signed_in?
 
         next if @account.user_hides_network?
 
diff --git a/app/controllers/following_accounts_controller.rb b/app/controllers/following_accounts_controller.rb
index 948725664..4d1ea4594 100644
--- a/app/controllers/following_accounts_controller.rb
+++ b/app/controllers/following_accounts_controller.rb
@@ -8,7 +8,7 @@ class FollowingAccountsController < ApplicationController
   def index
     respond_to do |format|
       format.html do
-        mark_cacheable! unless user_signed_in?
+        expires_in 0, public: true unless user_signed_in?
 
         next if @account.user_hides_network?
 
diff --git a/app/controllers/home_controller.rb b/app/controllers/home_controller.rb
index 85622a7b5..d1c525134 100644
--- a/app/controllers/home_controller.rb
+++ b/app/controllers/home_controller.rb
@@ -21,7 +21,7 @@ class HomeController < ApplicationController
       when 'statuses'
         status = Status.find_by(id: matches[2])
 
-        if status && (status.public_visibility? || status.unlisted_visibility?)
+        if status&.distributable?
           redirect_to(ActivityPub::TagManager.instance.url_for(status))
           return
         end
diff --git a/app/controllers/intents_controller.rb b/app/controllers/intents_controller.rb
index 9f41cf48a..ca89fc7fe 100644
--- a/app/controllers/intents_controller.rb
+++ b/app/controllers/intents_controller.rb
@@ -2,6 +2,7 @@
 
 class IntentsController < ApplicationController
   before_action :check_uri
+
   rescue_from Addressable::URI::InvalidURIError, with: :handle_invalid_uri
 
   def show
diff --git a/app/controllers/manifests_controller.rb b/app/controllers/manifests_controller.rb
index 332d845d8..1e5db4393 100644
--- a/app/controllers/manifests_controller.rb
+++ b/app/controllers/manifests_controller.rb
@@ -4,6 +4,7 @@ class ManifestsController < ApplicationController
   skip_before_action :store_current_location
 
   def show
+    expires_in 3.minutes, public: true
     render json: InstancePresenter.new, serializer: ManifestSerializer
   end
 end
diff --git a/app/controllers/media_controller.rb b/app/controllers/media_controller.rb
index d44b52d26..b3b7519a1 100644
--- a/app/controllers/media_controller.rb
+++ b/app/controllers/media_controller.rb
@@ -31,7 +31,6 @@ class MediaController < ApplicationController
   def verify_permitted_status!
     authorize @media_attachment.status, :show?
   rescue Mastodon::NotPermittedError
-    # Reraise in order to get a 404 instead of a 403 error code
     raise ActiveRecord::RecordNotFound
   end
 
diff --git a/app/controllers/public_timelines_controller.rb b/app/controllers/public_timelines_controller.rb
index 53d4472d8..23506b990 100644
--- a/app/controllers/public_timelines_controller.rb
+++ b/app/controllers/public_timelines_controller.rb
@@ -8,20 +8,16 @@ class PublicTimelinesController < ApplicationController
   before_action :set_instance_presenter
 
   def show
-    respond_to do |format|
-      format.html do
-        @initial_state_json = ActiveModelSerializers::SerializableResource.new(
-          InitialStatePresenter.new(settings: { known_fediverse: Setting.show_known_fediverse_at_about_page }, token: current_session&.token),
-          serializer: InitialStateSerializer
-        ).to_json
-      end
-    end
+    @initial_state_json = ActiveModelSerializers::SerializableResource.new(
+      InitialStatePresenter.new(settings: { known_fediverse: Setting.show_known_fediverse_at_about_page }, token: current_session&.token),
+      serializer: InitialStateSerializer
+    ).to_json
   end
 
   private
 
   def check_enabled
-    raise ActiveRecord::RecordNotFound unless Setting.timeline_preview
+    not_found unless Setting.timeline_preview
   end
 
   def set_body_classes
diff --git a/app/controllers/remote_follow_controller.rb b/app/controllers/remote_follow_controller.rb
index 8ba331cd1..0fb71d335 100644
--- a/app/controllers/remote_follow_controller.rb
+++ b/app/controllers/remote_follow_controller.rb
@@ -1,10 +1,10 @@
 # frozen_string_literal: true
 
 class RemoteFollowController < ApplicationController
+  include AccountOwnedConcern
+
   layout 'modal'
 
-  before_action :set_account
-  before_action :gone, if: :suspended_account?
   before_action :set_body_classes
 
   def new
@@ -32,14 +32,6 @@ class RemoteFollowController < ApplicationController
     { acct: session[:remote_follow] }
   end
 
-  def set_account
-    @account = Account.find_local!(params[:account_username])
-  end
-
-  def suspended_account?
-    @account.suspended?
-  end
-
   def set_body_classes
     @body_classes = 'modal-layout'
     @hide_header  = true
diff --git a/app/controllers/statuses_controller.rb b/app/controllers/statuses_controller.rb
index 776099ca8..13ce5c691 100644
--- a/app/controllers/statuses_controller.rb
+++ b/app/controllers/statuses_controller.rb
@@ -1,24 +1,21 @@
 # frozen_string_literal: true
 
 class StatusesController < ApplicationController
+  include StatusControllerConcern
   include SignatureAuthentication
   include Authorization
-
-  ANCESTORS_LIMIT         = 40
-  DESCENDANTS_LIMIT       = 60
-  DESCENDANTS_DEPTH_LIMIT = 20
+  include AccountOwnedConcern
 
   layout 'public'
 
-  before_action :set_account
   before_action :set_status
   before_action :set_instance_presenter
   before_action :set_link_headers
-  before_action :check_account_suspension
   before_action :redirect_to_original, only: [:show]
   before_action :set_referrer_policy_header, only: [:show]
   before_action :set_cache_headers
-  before_action :set_replies, only: [:replies]
+  before_action :set_body_classes
+  before_action :set_autoplay, only: :embed
 
   content_security_policy only: :embed do |p|
     p.frame_ancestors(false)
@@ -28,25 +25,20 @@ class StatusesController < ApplicationController
     respond_to do |format|
       format.html do
         expires_in 10.seconds, public: true if current_account.nil?
-
-        @body_classes = 'with-modals'
-
         set_ancestors
         set_descendants
       end
 
       format.json do
-        render_cached_json(['activitypub', 'note', @status], content_type: 'application/activity+json', public: @status.distributable?) do
-          ActiveModelSerializers::SerializableResource.new(@status, serializer: ActivityPub::NoteSerializer, adapter: ActivityPub::Adapter)
-        end
+        expires_in 3.minutes, public: @status.distributable?
+        render json: @status, content_type: 'application/activity+json', serializer: ActivityPub::NoteSerializer, adapter: ActivityPub::Adapter
       end
     end
   end
 
   def activity
-    render_cached_json(['activitypub', 'activity', @status], content_type: 'application/activity+json', public: @status.distributable?) do
-      ActiveModelSerializers::SerializableResource.new(@status, serializer: ActivityPub::ActivitySerializer, adapter: ActivityPub::Adapter)
-    end
+    expires_in 3.minutes, public: @status.distributable?
+    render json: @status, content_type: 'application/activity+json', serializer: ActivityPub::ActivitySerializer, adapter: ActivityPub::Adapter
   end
 
   def embed
@@ -54,120 +46,14 @@ class StatusesController < ApplicationController
 
     expires_in 180, public: true
     response.headers['X-Frame-Options'] = 'ALLOWALL'
-    @autoplay = ActiveModel::Type::Boolean.new.cast(params[:autoplay])
 
     render layout: 'embedded'
   end
 
-  def replies
-    render json: replies_collection_presenter,
-           serializer: ActivityPub::CollectionSerializer,
-           adapter: ActivityPub::Adapter,
-           content_type: 'application/activity+json',
-           skip_activities: true
-  end
-
   private
 
-  def replies_collection_presenter
-    page = ActivityPub::CollectionPresenter.new(
-      id: replies_account_status_url(@account, @status, page_params),
-      type: :unordered,
-      part_of: replies_account_status_url(@account, @status),
-      next: next_page,
-      items: @replies.map { |status| status.local ? status : status.id }
-    )
-    if page_requested?
-      page
-    else
-      ActivityPub::CollectionPresenter.new(
-        id: replies_account_status_url(@account, @status),
-        type: :unordered,
-        first: page
-      )
-    end
-  end
-
-  def create_descendant_thread(starting_depth, statuses)
-    depth = starting_depth + statuses.size
-
-    if depth < DESCENDANTS_DEPTH_LIMIT
-      {
-        statuses: statuses,
-        starting_depth: starting_depth,
-      }
-    else
-      next_status = statuses.pop
-
-      {
-        statuses: statuses,
-        starting_depth: starting_depth,
-        next_status: next_status,
-      }
-    end
-  end
-
-  def set_account
-    @account = Account.find_local!(params[:account_username])
-  end
-
-  def set_ancestors
-    @ancestors     = @status.reply? ? cache_collection(@status.ancestors(ANCESTORS_LIMIT, current_account), Status) : []
-    @next_ancestor = @ancestors.size < ANCESTORS_LIMIT ? nil : @ancestors.shift
-  end
-
-  def set_descendants
-    @max_descendant_thread_id   = params[:max_descendant_thread_id]&.to_i
-    @since_descendant_thread_id = params[:since_descendant_thread_id]&.to_i
-
-    descendants = cache_collection(
-      @status.descendants(
-        DESCENDANTS_LIMIT,
-        current_account,
-        @max_descendant_thread_id,
-        @since_descendant_thread_id,
-        DESCENDANTS_DEPTH_LIMIT
-      ),
-      Status
-    )
-
-    @descendant_threads = []
-
-    if descendants.present?
-      statuses       = [descendants.first]
-      starting_depth = 0
-
-      descendants.drop(1).each_with_index do |descendant, index|
-        if descendants[index].id == descendant.in_reply_to_id
-          statuses << descendant
-        else
-          @descendant_threads << create_descendant_thread(starting_depth, statuses)
-
-          # The thread is broken, assume it's a reply to the root status
-          starting_depth = 0
-
-          # ... unless we can find its ancestor in one of the already-processed threads
-          @descendant_threads.reverse_each do |descendant_thread|
-            statuses = descendant_thread[:statuses]
-
-            index = statuses.find_index do |thread_status|
-              thread_status.id == descendant.in_reply_to_id
-            end
-
-            if index.present?
-              starting_depth = descendant_thread[:starting_depth] + index + 1
-              break
-            end
-          end
-
-          statuses = [descendant]
-        end
-      end
-
-      @descendant_threads << create_descendant_thread(starting_depth, statuses)
-    end
-
-    @max_descendant_thread_id = @descendant_threads.pop[:statuses].first.id if descendants.size >= DESCENDANTS_LIMIT
+  def set_body_classes
+    @body_classes = 'with-modals'
   end
 
   def set_link_headers
@@ -185,39 +71,15 @@ class StatusesController < ApplicationController
     @instance_presenter = InstancePresenter.new
   end
 
-  def check_account_suspension
-    gone if @account.suspended?
-  end
-
   def redirect_to_original
     redirect_to ActivityPub::TagManager.instance.url_for(@status.reblog) if @status.reblog?
   end
 
   def set_referrer_policy_header
-    return if @status.public_visibility? || @status.unlisted_visibility?
-    response.headers['Referrer-Policy'] = 'origin'
-  end
-
-  def page_requested?
-    params[:page] == 'true'
-  end
-
-  def set_replies
-    @replies = page_params[:other_accounts] ? Status.where.not(account_id: @account.id) : @account.statuses
-    @replies = @replies.where(in_reply_to_id: @status.id, visibility: [:public, :unlisted])
-    @replies = @replies.paginate_by_min_id(DESCENDANTS_LIMIT, params[:min_id])
-  end
-
-  def next_page
-    last_reply = @replies.last
-    return if last_reply.nil?
-    same_account = last_reply.account_id == @account.id
-    return unless same_account || @replies.size == DESCENDANTS_LIMIT
-    same_account = false unless @replies.size == DESCENDANTS_LIMIT
-    replies_account_status_url(@account, @status, page: true, min_id: last_reply.id, other_accounts: !same_account)
+    response.headers['Referrer-Policy'] = 'origin' unless @status.distributable?
   end
 
-  def page_params
-    { page: true, other_accounts: params[:other_accounts], min_id: params[:min_id] }.compact
+  def set_autoplay
+    @autoplay = truthy_param?(:autoplay)
   end
 end
diff --git a/app/controllers/tags_controller.rb b/app/controllers/tags_controller.rb
index 66b184901..2ecce0ca2 100644
--- a/app/controllers/tags_controller.rb
+++ b/app/controllers/tags_controller.rb
@@ -5,14 +5,15 @@ class TagsController < ApplicationController
 
   layout 'public'
 
+  before_action :set_tag
   before_action :set_body_classes
   before_action :set_instance_presenter
 
   def show
-    @tag = Tag.find_normalized!(params[:id])
-
     respond_to do |format|
       format.html do
+        expires_in 0, public: true
+
         @initial_state_json = ActiveModelSerializers::SerializableResource.new(
           InitialStatePresenter.new(settings: {}, token: current_session&.token),
           serializer: InitialStateSerializer
@@ -20,6 +21,8 @@ class TagsController < ApplicationController
       end
 
       format.rss do
+        expires_in 0, public: true
+
         @statuses = HashtagQueryService.new.call(@tag, params.slice(:any, :all, :none)).limit(PAGE_SIZE)
         @statuses = cache_collection(@statuses, Status)
 
@@ -27,19 +30,22 @@ class TagsController < ApplicationController
       end
 
       format.json do
+        expires_in 3.minutes, public: true
+
         @statuses = HashtagQueryService.new.call(@tag, params.slice(:any, :all, :none), current_account, params[:local]).paginate_by_max_id(PAGE_SIZE, params[:max_id])
         @statuses = cache_collection(@statuses, Status)
 
-        render json: collection_presenter,
-               serializer: ActivityPub::CollectionSerializer,
-               adapter: ActivityPub::Adapter,
-               content_type: 'application/activity+json'
+        render json: collection_presenter, serializer: ActivityPub::CollectionSerializer, adapter: ActivityPub::Adapter, content_type: 'application/activity+json'
       end
     end
   end
 
   private
 
+  def set_tag
+    @tag = Tag.find_normalized!(params[:id])
+  end
+
   def set_body_classes
     @body_classes = 'with-modals'
   end
diff --git a/app/controllers/well_known/host_meta_controller.rb b/app/controllers/well_known/host_meta_controller.rb
index 5fb70288a..2e9298c4a 100644
--- a/app/controllers/well_known/host_meta_controller.rb
+++ b/app/controllers/well_known/host_meta_controller.rb
@@ -13,7 +13,7 @@ module WellKnown
         format.xml { render content_type: 'application/xrd+xml' }
       end
 
-      expires_in(3.days, public: true)
+      expires_in 3.days, public: true
     end
   end
 end
diff --git a/app/controllers/well_known/webfinger_controller.rb b/app/controllers/well_known/webfinger_controller.rb
index 28654b61d..53f7f1e27 100644
--- a/app/controllers/well_known/webfinger_controller.rb
+++ b/app/controllers/well_known/webfinger_controller.rb
@@ -19,7 +19,7 @@ module WellKnown
         end
       end
 
-      expires_in(3.days, public: true)
+      expires_in 3.days, public: true
     rescue ActiveRecord::RecordNotFound
       head 404
     end
@@ -27,12 +27,9 @@ module WellKnown
     private
 
     def username_from_resource
-      resource_user = resource_param
-
+      resource_user    = resource_param
       username, domain = resource_user.split('@')
-      if Rails.configuration.x.alternate_domains.include?(domain)
-        resource_user = "#{username}@#{Rails.configuration.x.local_domain}"
-      end
+      resource_user    = "#{username}@#{Rails.configuration.x.local_domain}" if Rails.configuration.x.alternate_domains.include?(domain)
 
       WebfingerResource.new(resource_user).username
     end
diff --git a/app/lib/activitypub/activity/announce.rb b/app/lib/activitypub/activity/announce.rb
index 1aa6ee9ec..34c646668 100644
--- a/app/lib/activitypub/activity/announce.rb
+++ b/app/lib/activitypub/activity/announce.rb
@@ -40,7 +40,7 @@ class ActivityPub::Activity::Announce < ActivityPub::Activity
   end
 
   def announceable?(status)
-    status.account_id == @account.id || status.public_visibility? || status.unlisted_visibility?
+    status.account_id == @account.id || status.distributable?
   end
 
   def related_to_local_activity?
diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 00f0dd42d..5849c20d7 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -42,7 +42,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     resolve_thread(@status)
     fetch_replies(@status)
     distribute(@status)
-    forward_for_reply if @status.public_visibility? || @status.unlisted_visibility?
+    forward_for_reply if @status.distributable?
   end
 
   def find_existing_status
diff --git a/app/lib/activitypub/activity/delete.rb b/app/lib/activitypub/activity/delete.rb
index 0eb14b89c..1f2b40c15 100644
--- a/app/lib/activitypub/activity/delete.rb
+++ b/app/lib/activitypub/activity/delete.rb
@@ -31,7 +31,7 @@ class ActivityPub::Activity::Delete < ActivityPub::Activity
 
     return if @status.nil?
 
-    if @status.public_visibility? || @status.unlisted_visibility?
+    if @status.distributable?
       forward_for_reply
       forward_for_reblogs
     end
diff --git a/app/lib/activitypub/tag_manager.rb b/app/lib/activitypub/tag_manager.rb
index 595291342..4d452f290 100644
--- a/app/lib/activitypub/tag_manager.rb
+++ b/app/lib/activitypub/tag_manager.rb
@@ -51,7 +51,7 @@ class ActivityPub::TagManager
   def replies_uri_for(target, page_params = nil)
     raise ArgumentError, 'target must be a local activity' unless %i(note comment activity).include?(target.object_type) && target.local?
 
-    replies_account_status_url(target.account, target, page_params)
+    account_status_replies_url(target.account, target, page_params)
   end
 
   # Primary audience of a status
diff --git a/app/models/status.rb b/app/models/status.rb
index 906756e85..6f1e35e4a 100644
--- a/app/models/status.rb
+++ b/app/models/status.rb
@@ -193,7 +193,7 @@ class Status < ApplicationRecord
   end
 
   def hidden?
-    private_visibility? || direct_visibility? || limited_visibility?
+    !distributable?
   end
 
   def distributable?
@@ -446,7 +446,8 @@ class Status < ApplicationRecord
   end
 
   def update_statistics
-    return unless public_visibility? || unlisted_visibility?
+    return unless distributable?
+
     ActivityTracker.increment('activity:statuses:local')
   end
 
@@ -455,7 +456,7 @@ class Status < ApplicationRecord
 
     account&.increment_count!(:statuses_count)
     reblog&.increment_count!(:reblogs_count) if reblog?
-    thread&.increment_count!(:replies_count) if in_reply_to_id.present? && (public_visibility? || unlisted_visibility?)
+    thread&.increment_count!(:replies_count) if in_reply_to_id.present? && distributable?
   end
 
   def decrement_counter_caches
@@ -463,7 +464,7 @@ class Status < ApplicationRecord
 
     account&.decrement_count!(:statuses_count)
     reblog&.decrement_count!(:reblogs_count) if reblog?
-    thread&.decrement_count!(:replies_count) if in_reply_to_id.present? && (public_visibility? || unlisted_visibility?)
+    thread&.decrement_count!(:replies_count) if in_reply_to_id.present? && distributable?
   end
 
   def unlink_from_conversations
diff --git a/app/serializers/activitypub/activity_serializer.rb b/app/serializers/activitypub/activity_serializer.rb
index c06d5c87c..fdedbc9d1 100644
--- a/app/serializers/activitypub/activity_serializer.rb
+++ b/app/serializers/activitypub/activity_serializer.rb
@@ -1,9 +1,12 @@
 # frozen_string_literal: true
 
 class ActivityPub::ActivitySerializer < ActivityPub::Serializer
+  cache key: 'activity', expires_in: 3.minutes
+
   attributes :id, :type, :actor, :published, :to, :cc
 
   has_one :proper, key: :object, serializer: ActivityPub::NoteSerializer, if: :serialize_object?
+
   attribute :proper_uri, key: :object, unless: :serialize_object?
   attribute :atom_uri, if: :announce?
 
diff --git a/app/serializers/activitypub/actor_serializer.rb b/app/serializers/activitypub/actor_serializer.rb
index 0644219fb..ab7be27f6 100644
--- a/app/serializers/activitypub/actor_serializer.rb
+++ b/app/serializers/activitypub/actor_serializer.rb
@@ -3,6 +3,8 @@
 class ActivityPub::ActorSerializer < ActivityPub::Serializer
   include RoutingHelper
 
+  cache key: 'actor', expires_in: 3.minutes
+
   context :security
 
   context_extensions :manually_approves_followers, :featured, :also_known_as,
diff --git a/app/serializers/activitypub/collection_serializer.rb b/app/serializers/activitypub/collection_serializer.rb
index da1ba735f..9dd8134d3 100644
--- a/app/serializers/activitypub/collection_serializer.rb
+++ b/app/serializers/activitypub/collection_serializer.rb
@@ -7,6 +7,8 @@ class ActivityPub::CollectionSerializer < ActivityPub::Serializer
     super
   end
 
+  cache key: 'collection', expires_in: 3.minutes
+
   attribute :id, if: -> { object.id.present? }
   attribute :type
   attribute :total_items, if: -> { object.size.present? }
diff --git a/app/serializers/activitypub/emoji_serializer.rb b/app/serializers/activitypub/emoji_serializer.rb
index 4dc38f3ea..08df25d7d 100644
--- a/app/serializers/activitypub/emoji_serializer.rb
+++ b/app/serializers/activitypub/emoji_serializer.rb
@@ -3,6 +3,8 @@
 class ActivityPub::EmojiSerializer < ActivityPub::Serializer
   include RoutingHelper
 
+  cache key: 'emoji', expires_in: 3.minutes
+
   context_extensions :emoji
 
   attributes :id, :type, :name, :updated
diff --git a/app/serializers/activitypub/note_serializer.rb b/app/serializers/activitypub/note_serializer.rb
index 67f596e78..87acc5429 100644
--- a/app/serializers/activitypub/note_serializer.rb
+++ b/app/serializers/activitypub/note_serializer.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class ActivityPub::NoteSerializer < ActivityPub::Serializer
+  cache key: 'note', expires_in: 3.minutes
+
   context_extensions :atom_uri, :conversation, :sensitive,
                      :hashtag, :emoji, :focal_point, :blurhash
 
diff --git a/app/services/process_hashtags_service.rb b/app/services/process_hashtags_service.rb
index d5ec076a8..b6974e598 100644
--- a/app/services/process_hashtags_service.rb
+++ b/app/services/process_hashtags_service.rb
@@ -14,7 +14,7 @@ class ProcessHashtagsService < BaseService
       TrendingTags.record_use!(tag, status.account, status.created_at) if status.public_visibility?
     end
 
-    return unless status.public_visibility? || status.unlisted_visibility?
+    return unless status.distributable?
 
     status.account.featured_tags.where(tag_id: records.map(&:id)).each do |featured_tag|
       featured_tag.increment(status.created_at)
diff --git a/app/views/statuses/_simple_status.html.haml b/app/views/statuses/_simple_status.html.haml
index 11220dfcb..38fde1be8 100644
--- a/app/views/statuses/_simple_status.html.haml
+++ b/app/views/statuses/_simple_status.html.haml
@@ -50,9 +50,9 @@
           = fa_icon 'reply-all fw'
       .status__action-bar__counter__label= obscured_counter status.replies_count
     = link_to remote_interaction_path(status, type: :reblog), class: 'status__action-bar-button icon-button modal-button', style: 'font-size: 18px; width: 23.1429px; height: 23.1429px; line-height: 23.15px;' do
-      - if status.public_visibility? || status.unlisted_visibility?
+      - if status.distributable?
         = fa_icon 'retweet fw'
-      - elsif status.private_visibility?
+      - elsif status.private_visibility? || status.limited_visibility?
         = fa_icon 'lock fw'
       - else
         = fa_icon 'envelope fw'
diff --git a/config/routes.rb b/config/routes.rb
index 69b495a96..115e7bb44 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -52,8 +52,9 @@ Rails.application.routes.draw do
       member do
         get :activity
         get :embed
-        get :replies
       end
+
+      resources :replies, only: [:index], module: :activitypub
     end
 
     resources :followers, only: [:index], controller: :follower_accounts
diff --git a/spec/controllers/concerns/account_controller_concern_spec.rb b/spec/controllers/concerns/account_controller_concern_spec.rb
index ea2b4a2a1..7ea214a7d 100644
--- a/spec/controllers/concerns/account_controller_concern_spec.rb
+++ b/spec/controllers/concerns/account_controller_concern_spec.rb
@@ -41,7 +41,7 @@ describe ApplicationController, type: :controller do
     it 'sets link headers' do
       account = Fabricate(:account, username: 'username', user: Fabricate(:user))
       get 'success', params: { account_username: 'username' }
-      expect(response.headers['Link'].to_s).to eq '<http://test.host/.well-known/webfinger?resource=acct%3Ausername%40cb6e6126.ngrok.io>; rel="lrdd"; type="application/xrd+xml", <http://test.host/users/username.atom>; rel="alternate"; type="application/atom+xml", <https://cb6e6126.ngrok.io/users/username>; rel="alternate"; type="application/activity+json"'
+      expect(response.headers['Link'].to_s).to eq '<http://test.host/.well-known/webfinger?resource=acct%3Ausername%40cb6e6126.ngrok.io>; rel="lrdd"; type="application/jrd+json", <https://cb6e6126.ngrok.io/users/username>; rel="alternate"; type="application/activity+json"'
     end
 
     it 'returns http success' do
diff --git a/spec/controllers/statuses_controller_spec.rb b/spec/controllers/statuses_controller_spec.rb
index 95e5c363c..6905dae10 100644
--- a/spec/controllers/statuses_controller_spec.rb
+++ b/spec/controllers/statuses_controller_spec.rb
@@ -92,7 +92,7 @@ describe StatusesController do
       end
 
       it 'assigns @max_descendant_thread_id for the last thread if it is hitting the status limit' do
-        stub_const 'StatusesController::DESCENDANTS_LIMIT', 1
+        stub_const 'StatusControllerConcern::DESCENDANTS_LIMIT', 1
         status = Fabricate(:status)
         child = Fabricate(:status, in_reply_to_id: status.id)
 
@@ -103,7 +103,7 @@ describe StatusesController do
       end
 
       it 'assigns @descendant_threads for threads with :next_status key if they are hitting the depth limit' do
-        stub_const 'StatusesController::DESCENDANTS_DEPTH_LIMIT', 2
+        stub_const 'StatusControllerConcern::DESCENDANTS_DEPTH_LIMIT', 2
         status = Fabricate(:status)
         child0 = Fabricate(:status, in_reply_to_id: status.id)
         child1 = Fabricate(:status, in_reply_to_id: child0.id)
diff --git a/spec/requests/link_headers_spec.rb b/spec/requests/link_headers_spec.rb
index 3dc408d92..712ee262b 100644
--- a/spec/requests/link_headers_spec.rb
+++ b/spec/requests/link_headers_spec.rb
@@ -11,16 +11,16 @@ describe 'Link headers' do
     end
 
     it 'contains webfinger url in link header' do
-      link_header = link_header_with_type('application/xrd+xml')
+      link_header = link_header_with_type('application/jrd+json')
 
       expect(link_header.href).to match 'http://www.example.com/.well-known/webfinger?resource=acct%3Atest%40cb6e6126.ngrok.io'
       expect(link_header.attr_pairs.first).to eq %w(rel lrdd)
     end
 
-    it 'contains atom url in link header' do
-      link_header = link_header_with_type('application/atom+xml')
+    it 'contains activitypub url in link header' do
+      link_header = link_header_with_type('application/activity+json')
 
-      expect(link_header.href).to eq 'http://www.example.com/users/test.atom'
+      expect(link_header.href).to eq 'https://cb6e6126.ngrok.io/users/test'
       expect(link_header.attr_pairs.first).to eq %w(rel alternate)
     end