Cache featured collections, as well as outbox, followers and following (#10467)

app/controllers/activitypub/collections_controller.rb

@@ -6,13 +6,19 @@ class ActivityPub::CollectionsController < Api::BaseController
   before_action :set_account
   before_action :set_size
   before_action :set_statuses
+  before_action :set_cache_headers
 
   def show
-    render json: collection_presenter,
-           serializer: ActivityPub::CollectionSerializer,
-           adapter: ActivityPub::Adapter,
-           content_type: 'application/activity+json',
-           skip_activities: true
+    skip_session!
+
+    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
   end
 
   private

app/controllers/activitypub/outboxes_controller.rb

@@ -7,8 +7,14 @@ class ActivityPub::OutboxesController < Api::BaseController
 
   before_action :set_account
   before_action :set_statuses
+  before_action :set_cache_headers
 
   def show
+    unless page_requested?
+      skip_session!
+      expires_in 1.minute, public: true
+    end
+
     render json: outbox_presenter, serializer: ActivityPub::OutboxSerializer, adapter: ActivityPub::Adapter, content_type: 'application/activity+json'
   end
 

app/controllers/follower_accounts_controller.rb

@@ -3,6 +3,8 @@
 class FollowerAccountsController < ApplicationController
   include AccountControllerConcern
 
+  before_action :set_cache_headers
+
   def index
     respond_to do |format|
       format.html do
@@ -17,6 +19,11 @@ class FollowerAccountsController < ApplicationController
       format.json do
         raise Mastodon::NotPermittedError if params[:page].present? && @account.user_hides_network?
 
+        if params[:page].blank?
+          skip_session!
+          expires_in 3.minutes, public: true
+        end
+
         render json: collection_presenter,
                serializer: ActivityPub::CollectionSerializer,
                adapter: ActivityPub::Adapter,

app/controllers/following_accounts_controller.rb

@@ -3,9 +3,13 @@
 class FollowingAccountsController < ApplicationController
   include AccountControllerConcern
 
+  before_action :set_cache_headers
+
   def index
     respond_to do |format|
       format.html do
+        mark_cacheable! unless user_signed_in?
+
         next if @account.user_hides_network?
 
         follows
@@ -15,6 +19,11 @@ class FollowingAccountsController < ApplicationController
       format.json do
         raise Mastodon::NotPermittedError if params[:page].present? && @account.user_hides_network?
 
+        if params[:page].blank?
+          skip_session!
+          expires_in 3.minutes, public: true
+        end
+
         render json: collection_presenter,
                serializer: ActivityPub::CollectionSerializer,
                adapter: ActivityPub::Adapter,