ActivityPub delivery (#4566)

* Deliver ActivityPub Like

* Deliver ActivityPub Undo-Like

* Deliver ActivityPub Create/Announce activities

* Deliver ActivityPub creates from mentions

* Deliver ActivityPub Block/Undo-Block

* Deliver ActivityPub Accept/Reject-Follow

* Deliver ActivityPub Undo-Follow

* Deliver ActivityPub Follow

* Deliver ActivityPub Delete activities

Incidentally fix #889

* Adjust BatchedRemoveStatusService for ActivityPub

* Add tests for ActivityPub workers

* Add tests for FollowService

* Add tests for FavouriteService, UnfollowService and PostStatusService

* Add tests for ReblogService, BlockService, UnblockService, ProcessMentionsService

* Add tests for AuthorizeFollowService, RejectFollowService, RemoveStatusService

* Add tests for BatchedRemoveStatusService

* Deliver updates to a local account to ActivityPub followers

* Minor adjustments

1 files changed, 21 insertions, 7 deletions

diff --git a/app/services/process_mentions_service.rb b/app/services/process_mentions_service.rb
index 438033d22..407fa8c18 100644
--- a/app/services/process_mentions_service.rb
+++ b/app/services/process_mentions_service.rb
@@ -28,18 +28,32 @@ class ProcessMentionsService < BaseService
     end
 
     status.mentions.includes(:account).each do |mention|
-      mentioned_account = mention.account
-
-      if mentioned_account.local?
-        NotifyService.new.call(mentioned_account, mention)
-      else
-        NotificationWorker.perform_async(stream_entry_to_xml(status.stream_entry), status.account_id, mentioned_account.id)
-      end
+      create_notification(status, mention)
     end
   end
 
   private
 
+  def create_notification(status, mention)
+    mentioned_account = mention.account
+
+    if mentioned_account.local?
+      NotifyService.new.call(mentioned_account, mention)
+    elsif mentioned_account.ostatus?
+      NotificationWorker.perform_async(stream_entry_to_xml(status.stream_entry), status.account_id, mentioned_account.id)
+    elsif mentioned_account.activitypub?
+      ActivityPub::DeliveryWorker.perform_async(build_json(mention.status), mention.status.account_id, mentioned_account.inbox_url)
+    end
+  end
+
+  def build_json(status)
+    ActiveModelSerializers::SerializableResource.new(
+      status,
+      serializer: ActivityPub::ActivitySerializer,
+      adapter: ActivityPub::Adapter
+    ).to_json
+  end
+
   def follow_remote_account_service
     @follow_remote_account_service ||= ResolveRemoteAccountService.new
   end