Refactor activity serialization (#37678)

app/controllers/api/v1/statuses/pins_controller.rb

@@ -26,7 +26,7 @@ class Api::V1::Statuses::PinsController < Api::V1::Statuses::BaseController
   def distribute_add_activity!
     json = ActiveModelSerializers::SerializableResource.new(
       @status,
-      serializer: ActivityPub::AddSerializer,
+      serializer: ActivityPub::AddNoteSerializer,
       adapter: ActivityPub::Adapter
     ).as_json
 
@@ -36,7 +36,7 @@ class Api::V1::Statuses::PinsController < Api::V1::Statuses::BaseController
   def distribute_remove_activity!
     json = ActiveModelSerializers::SerializableResource.new(
       @status,
-      serializer: ActivityPub::RemoveSerializer,
+      serializer: ActivityPub::RemoveNoteSerializer,
       adapter: ActivityPub::Adapter
     ).as_json
 

app/controllers/statuses_controller.rb

@@ -37,7 +37,7 @@ class StatusesController < ApplicationController
 
   def activity
     expires_in 3.minutes, public: @status.distributable? && public_fetch_mode?
-    render_with_cache json: ActivityPub::ActivityPresenter.from_status(@status), content_type: 'application/activity+json', serializer: ActivityPub::ActivitySerializer, adapter: ActivityPub::Adapter
+    render_with_cache json: @status, content_type: 'application/activity+json', serializer: activity_serializer, adapter: ActivityPub::Adapter
   end
 
   def embed
@@ -69,4 +69,8 @@ class StatusesController < ApplicationController
   def redirect_to_original
     redirect_to(ActivityPub::TagManager.instance.url_for(@status.reblog), allow_other_host: true) if @status.reblog?
   end
+
+  def activity_serializer
+    @status.reblog? ? ActivityPub::AnnounceNoteSerializer : ActivityPub::CreateNoteSerializer
+  end
 end

app/presenters/activitypub/activity_presenter.rb

@@ -1,30 +0,0 @@
-# frozen_string_literal: true
-
-class ActivityPub::ActivityPresenter < ActiveModelSerializers::Model
-  attributes :id, :type, :actor, :published, :to, :cc, :virtual_object
-
-  class << self
-    def from_status(status, allow_inlining: true)
-      new.tap do |presenter|
-        presenter.id        = ActivityPub::TagManager.instance.activity_uri_for(status)
-        presenter.type      = status.reblog? ? 'Announce' : 'Create'
-        presenter.actor     = ActivityPub::TagManager.instance.uri_for(status.account)
-        presenter.published = status.created_at
-        presenter.to        = ActivityPub::TagManager.instance.to(status)
-        presenter.cc        = ActivityPub::TagManager.instance.cc(status)
-
-        presenter.virtual_object = begin
-          if status.reblog?
-            if allow_inlining && status.account == status.proper.account && status.proper.private_visibility? && status.local?
-              status.proper
-            else
-              ActivityPub::TagManager.instance.uri_for(status.proper)
-            end
-          else
-            status.proper
-          end
-        end
-      end
-    end
-  end
-end

app/serializers/activitypub/activity_serializer.rb

@@ -1,20 +0,0 @@
-# frozen_string_literal: true
-
-class ActivityPub::ActivitySerializer < ActivityPub::Serializer
-  def self.serializer_for(model, options)
-    case model.class.name
-    when 'Status'
-      ActivityPub::NoteSerializer
-    else
-      super
-    end
-  end
-
-  attributes :id, :type, :actor, :published, :to, :cc
-
-  has_one :virtual_object, key: :object
-
-  def published
-    object.published.iso8601
-  end
-end

app/serializers/activitypub/add_featured_collection_serializer.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class ActivityPub::AddFeaturedCollectionSerializer < ActivityPub::Serializer
+  include RoutingHelper
+
+  attributes :type, :actor, :target
+  has_one :object, serializer: ActivityPub::FeaturedCollectionSerializer
+
+  def type
+    'Add'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+
+  def target
+    ap_account_featured_collections_url(object.account_id)
+  end
+end

app/serializers/activitypub/add_hashtag_serializer.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class ActivityPub::AddHashtagSerializer < ActivityPub::Serializer
+  attributes :type, :actor, :target
+
+  has_one :object, serializer: ActivityPub::HashtagSerializer
+
+  def type
+    'Add'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+
+  def target
+    # Technically this is not correct, as tags have their own collection.
+    # But sadly we do not store the collection URI for tags anywhere so cannot
+    # handle `Add` activities to that properly (yet). The receiving code for
+    # this currently looks at the type of the contained objects to do the
+    # right thing.
+    ActivityPub::TagManager.instance.collection_uri_for(object.account, :featured)
+  end
+end

app/serializers/activitypub/add_note_serializer.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class ActivityPub::AddNoteSerializer < ActivityPub::Serializer
+  attributes :type, :actor, :target
+
+  has_one :proper_object, key: :object
+
+  def type
+    'Add'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+
+  def proper_object
+    ActivityPub::TagManager.instance.uri_for(object)
+  end
+
+  def target
+    ActivityPub::TagManager.instance.collection_uri_for(object.account, :featured)
+  end
+end

app/serializers/activitypub/add_serializer.rb

@@ -1,55 +0,0 @@
-# frozen_string_literal: true
-
-class ActivityPub::AddSerializer < ActivityPub::Serializer
-  class UriSerializer < ActiveModel::Serializer
-    include RoutingHelper
-
-    def serializable_hash(*_args)
-      ActivityPub::TagManager.instance.uri_for(object)
-    end
-  end
-
-  def self.serializer_for(model, options)
-    case model
-    when Status
-      UriSerializer
-    when FeaturedTag
-      ActivityPub::HashtagSerializer
-    when Collection
-      ActivityPub::FeaturedCollectionSerializer
-    else
-      super
-    end
-  end
-
-  include RoutingHelper
-
-  attributes :type, :actor, :target
-  has_one :proper_object, key: :object
-
-  def type
-    'Add'
-  end
-
-  def actor
-    ActivityPub::TagManager.instance.uri_for(object.account)
-  end
-
-  def proper_object
-    object
-  end
-
-  def target
-    case object
-    when Status, FeaturedTag
-      # Technically this is not correct, as tags have their own collection.
-      # But sadly we do not store the collection URI for tags anywhere so cannot
-      # handle `Add` activities to that properly (yet). The receiving code for
-      # this currently looks at the type of the contained objects to do the
-      # right thing.
-      ActivityPub::TagManager.instance.collection_uri_for(object.account, :featured)
-    when Collection
-      ap_account_featured_collections_url(object.account_id)
-    end
-  end
-end

app/serializers/activitypub/announce_note_serializer.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+class ActivityPub::AnnounceNoteSerializer < ActivityPub::Serializer
+  def self.serializer_for(model, options)
+    return ActivityPub::NoteSerializer if model.is_a?(Status)
+
+    super
+  end
+
+  attributes :id, :type, :actor, :published, :to, :cc
+
+  has_one :virtual_object, key: :object
+
+  def id
+    ActivityPub::TagManager.instance.activity_uri_for(object)
+  end
+
+  def type
+    'Announce'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+
+  def to
+    ActivityPub::TagManager.instance.to(object)
+  end
+
+  def cc
+    ActivityPub::TagManager.instance.cc(object)
+  end
+
+  def published
+    object.created_at.iso8601
+  end
+
+  def virtual_object
+    if allow_inlining? && object.account == object.proper.account && object.proper.private_visibility? && object.local?
+      object.proper
+    else
+      ActivityPub::TagManager.instance.uri_for(object.proper)
+    end
+  end
+
+  private
+
+  def allow_inlining?
+    return instance_options[:allow_inlining] if instance_options.key?(:allow_inlining)
+
+    true
+  end
+end

app/serializers/activitypub/create_note_serializer.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class ActivityPub::CreateNoteSerializer < ActivityPub::Serializer
+  attributes :id, :type, :actor, :published, :to, :cc
+
+  has_one :object, serializer: ActivityPub::NoteSerializer
+
+  def id
+    ActivityPub::TagManager.instance.activity_uri_for(object)
+  end
+
+  def type
+    'Create'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+
+  def to
+    ActivityPub::TagManager.instance.to(object)
+  end
+
+  def cc
+    ActivityPub::TagManager.instance.cc(object)
+  end
+
+  def published
+    object.created_at.iso8601
+  end
+end

app/serializers/activitypub/delete_note_serializer.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class ActivityPub::DeleteSerializer < ActivityPub::Serializer
+class ActivityPub::DeleteNoteSerializer < ActivityPub::Serializer
   class TombstoneSerializer < ActivityPub::Serializer
     context_extensions :atom_uri
 

app/serializers/activitypub/outbox_serializer.rb

@@ -2,14 +2,15 @@
 
 class ActivityPub::OutboxSerializer < ActivityPub::CollectionSerializer
   def self.serializer_for(model, options)
-    if model.instance_of?(::ActivityPub::ActivityPresenter)
-      ActivityPub::ActivitySerializer
+    case model
+    when Status
+      model.reblog? ? ActivityPub::AnnounceNoteSerializer : ActivityPub::CreateNoteSerializer
     else
       super
     end
   end
 
   def items
-    object.items.map { |status| ActivityPub::ActivityPresenter.from_status(status) }
+    object.items
   end
 end

app/serializers/activitypub/remove_hashtag_serializer.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+class ActivityPub::RemoveHashtagSerializer < ActivityPub::Serializer
+  attributes :type, :actor, :target
+  has_one :object, serializer: ActivityPub::HashtagSerializer
+
+  def type
+    'Remove'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+
+  def target
+    ActivityPub::TagManager.instance.collection_uri_for(object.account, :featured)
+  end
+end

app/serializers/activitypub/remove_note_serializer.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+class ActivityPub::RemoveNoteSerializer < ActivityPub::Serializer
+  attributes :type, :actor, :target
+  has_one :proper_object, key: :object
+
+  def type
+    'Remove'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+
+  def proper_object
+    ActivityPub::TagManager.instance.uri_for(object)
+  end
+
+  def target
+    ActivityPub::TagManager.instance.collection_uri_for(object.account, :featured)
+  end
+end

app/serializers/activitypub/remove_serializer.rb

@@ -1,43 +0,0 @@
-# frozen_string_literal: true
-
-class ActivityPub::RemoveSerializer < ActivityPub::Serializer
-  class UriSerializer < ActiveModel::Serializer
-    include RoutingHelper
-
-    def serializable_hash(*_args)
-      ActivityPub::TagManager.instance.uri_for(object)
-    end
-  end
-
-  def self.serializer_for(model, options)
-    case model.class.name
-    when 'Status'
-      UriSerializer
-    when 'FeaturedTag'
-      ActivityPub::HashtagSerializer
-    else
-      super
-    end
-  end
-
-  include RoutingHelper
-
-  attributes :type, :actor, :target
-  has_one :proper_object, key: :object
-
-  def type
-    'Remove'
-  end
-
-  def actor
-    ActivityPub::TagManager.instance.uri_for(object.account)
-  end
-
-  def proper_object
-    object
-  end
-
-  def target
-    ActivityPub::TagManager.instance.collection_uri_for(object.account, :featured)
-  end
-end

app/serializers/activitypub/undo_announce_serializer.rb

@@ -3,7 +3,11 @@
 class ActivityPub::UndoAnnounceSerializer < ActivityPub::Serializer
   attributes :id, :type, :actor, :to
 
-  has_one :virtual_object, key: :object, serializer: ActivityPub::ActivitySerializer
+  has_one :virtual_object, key: :object, serializer: ActivityPub::AnnounceNoteSerializer do |serializer|
+    serializer.send(:instance_options)[:allow_inlining] = false
+
+    object
+  end
 
   def id
     [ActivityPub::TagManager.instance.uri_for(object.account), '#announces/', object.id, '/undo'].join
@@ -22,6 +26,6 @@ class ActivityPub::UndoAnnounceSerializer < ActivityPub::Serializer
   end
 
   def virtual_object
-    ActivityPub::ActivityPresenter.from_status(object, allow_inlining: false)
+    object
   end
 end

app/serializers/activitypub/update_actor_serializer.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class ActivityPub::UpdateSerializer < ActivityPub::Serializer
+class ActivityPub::UpdateActorSerializer < ActivityPub::Serializer
   attributes :id, :type, :actor, :to
 
   has_one :object, serializer: ActivityPub::ActorSerializer

app/serializers/activitypub/update_note_serializer.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+class ActivityPub::UpdateNoteSerializer < ActivityPub::Serializer
+  attributes :id, :type, :actor, :published, :to, :cc
+
+  has_one :object, serializer: ActivityPub::NoteSerializer
+
+  def id
+    [ActivityPub::TagManager.instance.uri_for(object), '#updates/', edited_at.to_i].join
+  end
+
+  def type
+    'Update'
+  end
+
+  def actor
+    ActivityPub::TagManager.instance.uri_for(object.account)
+  end
+
+  def to
+    ActivityPub::TagManager.instance.to(object)
+  end
+
+  def cc
+    ActivityPub::TagManager.instance.cc(object)
+  end
+
+  def published
+    edited_at.iso8601
+  end
+
+  private
+
+  def edited_at
+    instance_options[:updated_at]&.to_datetime || object.edited_at
+  end
+end

app/services/backup_service.rb

@@ -34,7 +34,8 @@ class BackupService < BaseService
       add_comma = true
 
       file.write(statuses.map do |status|
-        item = serialize_payload(ActivityPub::ActivityPresenter.from_status(status), ActivityPub::ActivitySerializer)
+        serializer = status.reblog? ? ActivityPub::AnnounceNoteSerializer : ActivityPub::CreateNoteSerializer
+        item = serialize_payload(status, serializer)
         item.delete(:@context)
 
         unless item[:type] == 'Announce' || item[:object][:attachment].blank?

app/services/create_collection_service.rb

@@ -32,6 +32,6 @@ class CreateCollectionService
   end
 
   def activity_json
-    ActiveModelSerializers::SerializableResource.new(@collection, serializer: ActivityPub::AddSerializer, adapter: ActivityPub::Adapter).to_json
+    ActiveModelSerializers::SerializableResource.new(@collection, serializer: ActivityPub::AddFeaturedCollectionSerializer, adapter: ActivityPub::Adapter).to_json
   end
 end

app/services/create_featured_tag_service.rb

@@ -26,6 +26,6 @@ class CreateFeaturedTagService < BaseService
   private
 
   def build_json(featured_tag)
-    Oj.dump(serialize_payload(featured_tag, ActivityPub::AddSerializer, signer: @account))
+    Oj.dump(serialize_payload(featured_tag, ActivityPub::AddHashtagSerializer, signer: @account))
   end
 end

app/services/reblog_service.rb

@@ -49,8 +49,4 @@ class ReblogService < BaseService
   def increment_statistics
     ActivityTracker.increment('activity:interactions')
   end
-
-  def build_json(reblog)
-    Oj.dump(serialize_payload(ActivityPub::ActivityPresenter.from_status(reblog), ActivityPub::ActivitySerializer, signer: reblog.account))
-  end
 end

app/services/remove_featured_tag_service.rb

@@ -26,6 +26,6 @@ class RemoveFeaturedTagService < BaseService
   private
 
   def build_json(featured_tag)
-    Oj.dump(serialize_payload(featured_tag, ActivityPub::RemoveSerializer, signer: @account))
+    Oj.dump(serialize_payload(featured_tag, ActivityPub::RemoveHashtagSerializer, signer: @account))
   end
 end

app/services/remove_status_service.rb

@@ -103,7 +103,7 @@ class RemoveStatusService < BaseService
   end
 
   def signed_activity_json
-    @signed_activity_json ||= Oj.dump(serialize_payload(@status, @status.reblog? ? ActivityPub::UndoAnnounceSerializer : ActivityPub::DeleteSerializer, signer: @account, always_sign: true))
+    @signed_activity_json ||= Oj.dump(serialize_payload(@status, @status.reblog? ? ActivityPub::UndoAnnounceSerializer : ActivityPub::DeleteNoteSerializer, signer: @account, always_sign: true))
   end
 
   def remove_reblogs

app/services/suspend_account_service.rb

@@ -72,6 +72,6 @@ class SuspendAccountService < BaseService
   end
 
   def signed_activity_json
-    @signed_activity_json ||= Oj.dump(serialize_payload(@account, ActivityPub::UpdateSerializer, signer: @account))
+    @signed_activity_json ||= Oj.dump(serialize_payload(@account, ActivityPub::UpdateActorSerializer, signer: @account))
   end
 end

app/services/unsuspend_account_service.rb

@@ -63,6 +63,6 @@ class UnsuspendAccountService < BaseService
   end
 
   def signed_activity_json
-    @signed_activity_json ||= Oj.dump(serialize_payload(@account, ActivityPub::UpdateSerializer, signer: @account))
+    @signed_activity_json ||= Oj.dump(serialize_payload(@account, ActivityPub::UpdateActorSerializer, signer: @account))
   end
 end

app/workers/activitypub/distribution_worker.rb

@@ -24,11 +24,15 @@ class ActivityPub::DistributionWorker < ActivityPub::RawDistributionWorker
   end
 
   def payload
-    @payload ||= Oj.dump(serialize_payload(activity, ActivityPub::ActivitySerializer, signer: @account))
+    @payload ||= Oj.dump(serialize_payload(@status, activity_serializer, serializer_options.merge(signer: @account)))
   end
 
-  def activity
-    ActivityPub::ActivityPresenter.from_status(@status)
+  def activity_serializer
+    @status.reblog? ? ActivityPub::AnnounceNoteSerializer : ActivityPub::CreateNoteSerializer
+  end
+
+  def serializer_options
+    {}
   end
 
   def options

app/workers/activitypub/status_update_distribution_worker.rb

@@ -15,15 +15,11 @@ class ActivityPub::StatusUpdateDistributionWorker < ActivityPub::DistributionWor
 
   protected
 
-  def activity
-    ActivityPub::ActivityPresenter.new(
-      id: [ActivityPub::TagManager.instance.uri_for(@status), '#updates/', @options[:updated_at]&.to_datetime&.to_i || @status.edited_at.to_i].join,
-      type: 'Update',
-      actor: ActivityPub::TagManager.instance.uri_for(@status.account),
-      published: @options[:updated_at]&.to_datetime || @status.edited_at,
-      to: ActivityPub::TagManager.instance.to(@status),
-      cc: ActivityPub::TagManager.instance.cc(@status),
-      virtual_object: @status
-    )
+  def activity_serializer
+    ActivityPub::UpdateNoteSerializer
+  end
+
+  def serializer_options
+    super.merge({ updated_at: @options[:updated_at] })
   end
 end

app/workers/activitypub/update_distribution_worker.rb

@@ -23,6 +23,6 @@ class ActivityPub::UpdateDistributionWorker < ActivityPub::RawDistributionWorker
   end
 
   def payload
-    @payload ||= Oj.dump(serialize_payload(@account, ActivityPub::UpdateSerializer, signer: @account, sign_with: @options[:sign_with]))
+    @payload ||= Oj.dump(serialize_payload(@account, ActivityPub::UpdateActorSerializer, signer: @account, sign_with: @options[:sign_with]))
   end
 end

spec/serializers/activitypub/activity_serializer_spec.rb

@@ -1,102 +0,0 @@
-# frozen_string_literal: true
-
-require 'rails_helper'
-
-RSpec.describe ActivityPub::ActivitySerializer do
-  subject { serialized_record_json(presenter, described_class, adapter: ActivityPub::Adapter) }
-
-  let(:tag_manager) { ActivityPub::TagManager.instance }
-  let(:status) { Fabricate(:status, created_at: Time.utc(2026, 0o1, 27, 15, 29, 31)) }
-
-  context 'with a new status' do
-    let(:presenter) { ActivityPub::ActivityPresenter.from_status(status) }
-
-    it 'serializes to the expected json' do
-      expect(subject).to include({
-        'id' => tag_manager.activity_uri_for(status),
-        'type' => 'Create',
-        'actor' => tag_manager.uri_for(status.account),
-        'published' => '2026-01-27T15:29:31Z',
-        'to' => ['https://www.w3.org/ns/activitystreams#Public'],
-        'cc' => [a_string_matching(/followers$/)],
-        'object' => a_hash_including(
-          'id' => tag_manager.uri_for(status)
-        ),
-      })
-
-      expect(subject).to_not have_key('target')
-    end
-  end
-
-  context 'with a new reblog' do
-    let(:reblog) { Fabricate(:status, reblog: status, created_at: Time.utc(2026, 0o1, 27, 16, 21, 44)) }
-    let(:presenter) { ActivityPub::ActivityPresenter.from_status(reblog) }
-
-    it 'serializes to the expected json' do
-      expect(subject).to include({
-        'id' => tag_manager.activity_uri_for(reblog),
-        'type' => 'Announce',
-        'actor' => tag_manager.uri_for(reblog.account),
-        'published' => '2026-01-27T16:21:44Z',
-        'to' => ['https://www.w3.org/ns/activitystreams#Public'],
-        'cc' => [tag_manager.uri_for(status.account), a_string_matching(/followers$/)],
-        'object' => tag_manager.uri_for(status),
-      })
-
-      expect(subject).to_not have_key('target')
-    end
-
-    context 'when inlining of private local status is allowed' do
-      let(:status) { Fabricate(:status, visibility: :private, created_at: Time.utc(2026, 0o1, 27, 15, 29, 31)) }
-      let(:reblog) { Fabricate(:status, reblog: status, account: status.account, created_at: Time.utc(2026, 0o1, 27, 16, 21, 44)) }
-      let(:presenter) { ActivityPub::ActivityPresenter.from_status(reblog, allow_inlining: true) }
-
-      it 'serializes to the expected json' do
-        expect(subject).to include({
-          'id' => tag_manager.activity_uri_for(reblog),
-          'type' => 'Announce',
-          'actor' => tag_manager.uri_for(reblog.account),
-          'published' => '2026-01-27T16:21:44Z',
-          'to' => ['https://www.w3.org/ns/activitystreams#Public'],
-          'cc' => [tag_manager.uri_for(status.account), a_string_matching(/followers$/)],
-          'object' => a_hash_including(
-            'id' => tag_manager.uri_for(status)
-          ),
-        })
-
-        expect(subject).to_not have_key('target')
-      end
-    end
-  end
-
-  context 'with a custom presenter for a status `Update`' do
-    let(:status) { Fabricate(:status, edited_at: Time.utc(2026, 0o1, 27, 15, 29, 31)) }
-    let(:presenter) do
-      ActivityPub::ActivityPresenter.new(
-        id: 'https://localhost/status/1#updates/1769527771',
-        type: 'Update',
-        actor: 'https://localhost/actor/1',
-        published: status.edited_at,
-        to: ['https://www.w3.org/ns/activitystreams#Public'],
-        cc: ['https://localhost/actor/1/followers'],
-        virtual_object: status
-      )
-    end
-
-    it 'serializes to the expected json' do
-      expect(subject).to include({
-        'id' => 'https://localhost/status/1#updates/1769527771',
-        'type' => 'Update',
-        'actor' => 'https://localhost/actor/1',
-        'published' => '2026-01-27T15:29:31Z',
-        'to' => ['https://www.w3.org/ns/activitystreams#Public'],
-        'cc' => ['https://localhost/actor/1/followers'],
-        'object' => a_hash_including(
-          'id' => tag_manager.uri_for(status)
-        ),
-      })
-
-      expect(subject).to_not have_key('target')
-    end
-  end
-end

spec/serializers/activitypub/add_featured_collection_serializer_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ActivityPub::AddFeaturedCollectionSerializer do
+  subject { serialized_record_json(object, described_class, adapter: ActivityPub::Adapter) }
+
+  let(:tag_manager) { ActivityPub::TagManager.instance }
+  let(:object) { Fabricate(:collection) }
+
+  it 'serializes to the expected json' do
+    expect(subject).to include({
+      'type' => 'Add',
+      'actor' => tag_manager.uri_for(object.account),
+      'target' => a_string_matching(%r{/featured_collections$}),
+      'object' => a_hash_including({
+        'type' => 'FeaturedCollection',
+      }),
+    })
+
+    expect(subject).to_not have_key('id')
+    expect(subject).to_not have_key('published')
+    expect(subject).to_not have_key('to')
+    expect(subject).to_not have_key('cc')
+  end
+end

spec/serializers/activitypub/add_hashtag_serializer_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ActivityPub::AddHashtagSerializer do
+  subject { serialized_record_json(object, described_class, adapter: ActivityPub::Adapter) }
+
+  let(:tag_manager) { ActivityPub::TagManager.instance }
+  let(:object) { Fabricate(:featured_tag) }
+
+  it 'serializes to the expected json' do
+    expect(subject).to include({
+      'type' => 'Add',
+      'actor' => tag_manager.uri_for(object.account),
+      'target' => a_string_matching(%r{/featured$}),
+      'object' => a_hash_including({
+        'type' => 'Hashtag',
+      }),
+    })
+
+    expect(subject).to_not have_key('id')
+    expect(subject).to_not have_key('published')
+    expect(subject).to_not have_key('to')
+    expect(subject).to_not have_key('cc')
+  end
+end

spec/serializers/activitypub/add_note_serializer_spec.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ActivityPub::AddNoteSerializer do
+  subject { serialized_record_json(object, described_class, adapter: ActivityPub::Adapter) }
+
+  let(:tag_manager) { ActivityPub::TagManager.instance }
+  let(:object) { Fabricate(:status) }
+
+  it 'serializes to the expected json' do
+    expect(subject).to include({
+      'type' => 'Add',
+      'actor' => tag_manager.uri_for(object.account),
+      'target' => a_string_matching(%r{/featured$}),
+      'object' => tag_manager.uri_for(object),
+    })
+
+    expect(subject).to_not have_key('id')
+    expect(subject).to_not have_key('published')
+    expect(subject).to_not have_key('to')
+    expect(subject).to_not have_key('cc')
+  end
+end

spec/serializers/activitypub/add_serializer_spec.rb

@@ -1,119 +0,0 @@
-# frozen_string_literal: true
-
-require 'rails_helper'
-
-RSpec.describe ActivityPub::AddSerializer do
-  describe '.serializer_for' do
-    subject { described_class.serializer_for(model, {}) }
-
-    context 'with a Status model' do
-      let(:model) { Status.new }
-
-      it { is_expected.to eq(described_class::UriSerializer) }
-    end
-
-    context 'with a FeaturedTag model' do
-      let(:model) { FeaturedTag.new }
-
-      it { is_expected.to eq(ActivityPub::HashtagSerializer) }
-    end
-
-    context 'with a Collection model' do
-      let(:model) { Collection.new }
-
-      it { is_expected.to eq(ActivityPub::FeaturedCollectionSerializer) }
-    end
-
-    context 'with an Array' do
-      let(:model) { [] }
-
-      it { is_expected.to eq(ActiveModel::Serializer::CollectionSerializer) }
-    end
-  end
-
-  describe '#target' do
-    subject { described_class.new(object).target }
-
-    context 'when object is a Status' do
-      let(:object) { Fabricate(:status) }
-
-      it { is_expected.to match(%r{/#{object.account_id}/collections/featured$}) }
-    end
-
-    context 'when object is a FeaturedTag' do
-      let(:object) { Fabricate(:featured_tag) }
-
-      it { is_expected.to match(%r{/#{object.account_id}/collections/featured$}) }
-    end
-
-    context 'when object is a Collection' do
-      let(:object) { Fabricate(:collection) }
-
-      it { is_expected.to match(%r{/#{object.account_id}/featured_collections$}) }
-    end
-  end
-
-  describe 'Serialization' do
-    subject { serialized_record_json(object, described_class, adapter: ActivityPub::Adapter) }
-
-    let(:tag_manager) { ActivityPub::TagManager.instance }
-
-    context 'with a status' do
-      let(:object) { Fabricate(:status) }
-
-      it 'serializes to the expected json' do
-        expect(subject).to include({
-          'type' => 'Add',
-          'actor' => tag_manager.uri_for(object.account),
-          'target' => a_string_matching(%r{/featured$}),
-          'object' => tag_manager.uri_for(object),
-        })
-
-        expect(subject).to_not have_key('id')
-        expect(subject).to_not have_key('published')
-        expect(subject).to_not have_key('to')
-        expect(subject).to_not have_key('cc')
-      end
-    end
-
-    context 'with a featured tag' do
-      let(:object) { Fabricate(:featured_tag) }
-
-      it 'serializes to the expected json' do
-        expect(subject).to include({
-          'type' => 'Add',
-          'actor' => tag_manager.uri_for(object.account),
-          'target' => a_string_matching(%r{/featured$}),
-          'object' => a_hash_including({
-            'type' => 'Hashtag',
-          }),
-        })
-
-        expect(subject).to_not have_key('id')
-        expect(subject).to_not have_key('published')
-        expect(subject).to_not have_key('to')
-        expect(subject).to_not have_key('cc')
-      end
-    end
-
-    context 'with a collection' do
-      let(:object) { Fabricate(:collection) }
-
-      it 'serializes to the expected json' do
-        expect(subject).to include({
-          'type' => 'Add',
-          'actor' => tag_manager.uri_for(object.account),
-          'target' => a_string_matching(%r{/featured_collections$}),
-          'object' => a_hash_including({
-            'type' => 'FeaturedCollection',
-          }),
-        })
-
-        expect(subject).to_not have_key('id')
-        expect(subject).to_not have_key('published')
-        expect(subject).to_not have_key('to')
-        expect(subject).to_not have_key('cc')
-      end
-    end
-  end
-end

spec/serializers/activitypub/announce_note_serializer_spec.rb

@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ActivityPub::AnnounceNoteSerializer do
+  subject { serialized_record_json(reblog, described_class, adapter: ActivityPub::Adapter, options:) }
+
+  let(:tag_manager) { ActivityPub::TagManager.instance }
+  let(:status) { Fabricate(:status, created_at: Time.utc(2026, 1, 27, 15, 29, 31)) }
+  let(:reblog) { Fabricate(:status, reblog: status, created_at: Time.utc(2026, 1, 27, 16, 21, 44)) }
+  let(:options) { {} }
+
+  it 'serializes to the expected json' do
+    expect(subject).to include({
+      'id' => tag_manager.activity_uri_for(reblog),
+      'type' => 'Announce',
+      'actor' => tag_manager.uri_for(reblog.account),
+      'published' => '2026-01-27T16:21:44Z',
+      'to' => ['https://www.w3.org/ns/activitystreams#Public'],
+      'cc' => [tag_manager.uri_for(status.account), a_string_matching(/followers$/)],
+      'object' => tag_manager.uri_for(status),
+    })
+
+    expect(subject).to_not have_key('target')
+  end
+
+  context 'when status is local and private' do
+    let(:status) { Fabricate(:status, visibility: :private, created_at: Time.utc(2026, 1, 27, 15, 29, 31)) }
+    let(:reblog) { Fabricate(:status, reblog: status, account: status.account, created_at: Time.utc(2026, 1, 27, 16, 21, 44)) }
+
+    context 'when inlining of private local status is allowed' do
+      shared_examples 'serialization with inlining' do
+        it 'serializes to the expected json' do
+          expect(subject).to include({
+            'id' => tag_manager.activity_uri_for(reblog),
+            'type' => 'Announce',
+            'actor' => tag_manager.uri_for(reblog.account),
+            'published' => '2026-01-27T16:21:44Z',
+            'to' => ['https://www.w3.org/ns/activitystreams#Public'],
+            'cc' => [tag_manager.uri_for(status.account), a_string_matching(/followers$/)],
+            'object' => a_hash_including(
+              'id' => tag_manager.uri_for(status)
+            ),
+          })
+
+          expect(subject).to_not have_key('target')
+        end
+      end
+
+      context 'with `allow_inlining` explicitly set to `true`' do
+        let(:options) { { allow_inlining: true } }
+
+        it_behaves_like 'serialization with inlining'
+      end
+
+      context 'with `allow_inlining` unset' do
+        let(:options) { {} }
+
+        it_behaves_like 'serialization with inlining'
+      end
+    end
+
+    context 'when inlining is not allowed' do
+      let(:options) { { allow_inlining: false } }
+
+      it 'serializes to the expected json' do
+        expect(subject).to include({
+          'id' => tag_manager.activity_uri_for(reblog),
+          'type' => 'Announce',
+          'actor' => tag_manager.uri_for(reblog.account),
+          'published' => '2026-01-27T16:21:44Z',
+          'to' => ['https://www.w3.org/ns/activitystreams#Public'],
+          'cc' => [tag_manager.uri_for(status.account), a_string_matching(/followers$/)],
+          'object' => tag_manager.uri_for(status),
+        })
+      end
+    end
+  end
+end

spec/serializers/activitypub/create_note_serializer_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ActivityPub::CreateNoteSerializer do
+  subject { serialized_record_json(status, described_class, adapter: ActivityPub::Adapter) }
+
+  let(:tag_manager) { ActivityPub::TagManager.instance }
+  let(:status) { Fabricate(:status, created_at: Time.utc(2026, 1, 27, 15, 29, 31)) }
+
+  it 'serializes to the expected json' do
+    expect(subject).to include({
+      'id' => tag_manager.activity_uri_for(status),
+      'type' => 'Create',
+      'actor' => tag_manager.uri_for(status.account),
+      'published' => '2026-01-27T15:29:31Z',
+      'to' => ['https://www.w3.org/ns/activitystreams#Public'],
+      'cc' => [a_string_matching(/followers$/)],
+      'object' => a_hash_including(
+        'id' => tag_manager.uri_for(status)
+      ),
+    })
+
+    expect(subject).to_not have_key('target')
+  end
+end

spec/serializers/activitypub/delete_note_serializer_spec.rb

@@ -2,7 +2,7 @@
 
 require 'rails_helper'
 
-RSpec.describe ActivityPub::DeleteSerializer do
+RSpec.describe ActivityPub::DeleteNoteSerializer do
   subject { serialized_record_json(status, described_class, adapter: ActivityPub::Adapter) }
 
   let(:tag_manager) { ActivityPub::TagManager.instance }

spec/serializers/activitypub/remove_hashtag_serializer_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ActivityPub::RemoveHashtagSerializer do
+  subject { serialized_record_json(object, described_class, adapter: ActivityPub::Adapter) }
+
+  let(:tag_manager) { ActivityPub::TagManager.instance }
+  let(:object) { Fabricate(:featured_tag) }
+
+  it 'serializes to the expected json' do
+    expect(subject).to include({
+      'type' => 'Remove',
+      'actor' => tag_manager.uri_for(object.account),
+      'target' => a_string_matching(%r{/featured$}),
+      'object' => a_hash_including({
+        'type' => 'Hashtag',
+      }),
+    })
+
+    expect(subject).to_not have_key('id')
+    expect(subject).to_not have_key('published')
+    expect(subject).to_not have_key('to')
+    expect(subject).to_not have_key('cc')
+  end
+end

spec/serializers/activitypub/remove_note_serializer_spec.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ActivityPub::RemoveNoteSerializer do
+  subject { serialized_record_json(object, described_class, adapter: ActivityPub::Adapter) }
+
+  let(:tag_manager) { ActivityPub::TagManager.instance }
+  let(:object) { Fabricate(:status) }
+
+  it 'serializes to the expected json' do
+    expect(subject).to include({
+      'type' => 'Remove',
+      'actor' => tag_manager.uri_for(object.account),
+      'target' => a_string_matching(%r{/featured$}),
+      'object' => tag_manager.uri_for(object),
+    })
+
+    expect(subject).to_not have_key('id')
+    expect(subject).to_not have_key('published')
+    expect(subject).to_not have_key('to')
+    expect(subject).to_not have_key('cc')
+  end
+end

spec/serializers/activitypub/remove_serializer_spec.rb

@@ -1,71 +0,0 @@
-# frozen_string_literal: true
-
-require 'rails_helper'
-
-RSpec.describe ActivityPub::RemoveSerializer do
-  describe '.serializer_for' do
-    subject { described_class.serializer_for(model, {}) }
-
-    context 'with a Status model' do
-      let(:model) { Status.new }
-
-      it { is_expected.to eq(described_class::UriSerializer) }
-    end
-
-    context 'with a FeaturedTag model' do
-      let(:model) { FeaturedTag.new }
-
-      it { is_expected.to eq(ActivityPub::HashtagSerializer) }
-    end
-
-    context 'with an Array' do
-      let(:model) { [] }
-
-      it { is_expected.to eq(ActiveModel::Serializer::CollectionSerializer) }
-    end
-  end
-
-  describe 'Serialization' do
-    subject { serialized_record_json(object, described_class, adapter: ActivityPub::Adapter) }
-
-    let(:tag_manager) { ActivityPub::TagManager.instance }
-
-    context 'with a status' do
-      let(:object) { Fabricate(:status) }
-
-      it 'serializes to the expected json' do
-        expect(subject).to include({
-          'type' => 'Remove',
-          'actor' => tag_manager.uri_for(object.account),
-          'target' => a_string_matching(%r{/featured$}),
-          'object' => tag_manager.uri_for(object),
-        })
-
-        expect(subject).to_not have_key('id')
-        expect(subject).to_not have_key('published')
-        expect(subject).to_not have_key('to')
-        expect(subject).to_not have_key('cc')
-      end
-    end
-
-    context 'with a featured tag' do
-      let(:object) { Fabricate(:featured_tag) }
-
-      it 'serializes to the expected json' do
-        expect(subject).to include({
-          'type' => 'Remove',
-          'actor' => tag_manager.uri_for(object.account),
-          'target' => a_string_matching(%r{/featured$}),
-          'object' => a_hash_including({
-            'type' => 'Hashtag',
-          }),
-        })
-
-        expect(subject).to_not have_key('id')
-        expect(subject).to_not have_key('published')
-        expect(subject).to_not have_key('to')
-        expect(subject).to_not have_key('cc')
-      end
-    end
-  end
-end

spec/serializers/activitypub/undo_announce_serializer_spec.rb

@@ -26,4 +26,17 @@ RSpec.describe ActivityPub::UndoAnnounceSerializer do
     expect(subject).to_not have_key('cc')
     expect(subject).to_not have_key('target')
   end
+
+  context 'when status is local and private' do
+    let(:status) { Fabricate(:status, visibility: :private) }
+    let(:reblog) { Fabricate(:status, reblog: status, account: status.account) }
+
+    it 'does not inline the status' do
+      expect(subject).to include({
+        'object' => a_hash_including({
+          'object' => tag_manager.uri_for(status),
+        }),
+      })
+    end
+  end
 end

spec/serializers/activitypub/update_actor_serializer_spec.rb

@@ -2,7 +2,7 @@
 
 require 'rails_helper'
 
-RSpec.describe ActivityPub::UpdateSerializer do
+RSpec.describe ActivityPub::UpdateActorSerializer do
   subject { serialized_record_json(account, described_class, adapter: ActivityPub::Adapter) }
 
   let(:tag_manager) { ActivityPub::TagManager.instance }

spec/serializers/activitypub/update_note_serializer_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ActivityPub::UpdateNoteSerializer do
+  subject { serialized_record_json(status, described_class, adapter: ActivityPub::Adapter) }
+
+  let(:tag_manager) { ActivityPub::TagManager.instance }
+  let(:status) { Fabricate(:status, edited_at: Time.utc(2026, 1, 27, 15, 29, 31)) }
+
+  it 'serializes to the expected json' do
+    expect(subject).to include({
+      'id' => "#{tag_manager.uri_for(status)}#updates/1769527771",
+      'type' => 'Update',
+      'actor' => tag_manager.uri_for(status.account),
+      'published' => '2026-01-27T15:29:31Z',
+      'to' => ['https://www.w3.org/ns/activitystreams#Public'],
+      'cc' => [a_string_matching(%r{/followers$})],
+      'object' => a_hash_including(
+        'id' => tag_manager.uri_for(status)
+      ),
+    })
+
+    expect(subject).to_not have_key('target')
+  end
+end

spec/workers/activitypub/distribution_worker_spec.rb

@@ -51,5 +51,46 @@ RSpec.describe ActivityPub::DistributionWorker do
         end
       end
     end
+
+    context 'with a reblog' do
+      before do
+        follower.follow!(reblog.account)
+      end
+
+      context 'when the reblogged status is not private' do
+        let(:status) { Fabricate(:status) }
+        let(:reblog) { Fabricate(:status, reblog: status) }
+
+        it 'delivers an activity without inlining the status' do
+          expected_json = {
+            type: 'Announce',
+            object: ActivityPub::TagManager.instance.uri_for(status),
+          }
+
+          expect_push_bulk_to_match(ActivityPub::DeliveryWorker, [[match_json_values(expected_json), reblog.account.id, 'http://example.com', anything]]) do
+            subject.perform(reblog.id)
+          end
+        end
+      end
+
+      context 'when the reblogged status is private' do
+        let(:status) { Fabricate(:status, visibility: :private) }
+        let(:reblog) { Fabricate(:status, reblog: status, account: status.account) }
+
+        it 'delivers an activity that inlines the status' do
+          expected_json = {
+            type: 'Announce',
+            object: a_hash_including({
+              id: ActivityPub::TagManager.instance.uri_for(status),
+              type: 'Note',
+            }),
+          }
+
+          expect_push_bulk_to_match(ActivityPub::DeliveryWorker, [[match_json_values(expected_json), reblog.account.id, 'http://example.com', anything]]) do
+            subject.perform(reblog.id)
+          end
+        end
+      end
+    end
   end
 end