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, 12 insertions, 2 deletions

diff --git a/app/services/follow_service.rb b/app/services/follow_service.rb
index 3155feaa4..2be625cd8 100644
--- a/app/services/follow_service.rb
+++ b/app/services/follow_service.rb
@@ -14,7 +14,7 @@ class FollowService < BaseService
 
     return if source_account.following?(target_account)
 
-    if target_account.locked?
+    if target_account.locked? || target_account.activitypub?
       request_follow(source_account, target_account)
     else
       direct_follow(source_account, target_account)
@@ -28,9 +28,11 @@ class FollowService < BaseService
 
     if target_account.local?
       NotifyService.new.call(target_account, follow_request)
-    else
+    elsif target_account.ostatus?
       NotificationWorker.perform_async(build_follow_request_xml(follow_request), source_account.id, target_account.id)
       AfterRemoteFollowRequestWorker.perform_async(follow_request.id)
+    elsif target_account.activitypub?
+      ActivityPub::DeliveryWorker.perform_async(build_json(follow_request), source_account.id, target_account.inbox_url)
     end
 
     follow_request
@@ -63,4 +65,12 @@ class FollowService < BaseService
   def build_follow_xml(follow)
     OStatus::AtomSerializer.render(OStatus::AtomSerializer.new.follow_salmon(follow))
   end
+
+  def build_json(follow_request)
+    ActiveModelSerializers::SerializableResource.new(
+      follow_request,
+      serializer: ActivityPub::FollowSerializer,
+      adapter: ActivityPub::Adapter
+    ).to_json
+  end
 end