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, 42 insertions, 7 deletions

diff --git a/app/services/remove_status_service.rb b/app/services/remove_status_service.rb
index a5281f586..fcccbaa24 100644
--- a/app/services/remove_status_service.rb
+++ b/app/services/remove_status_service.rb
@@ -22,8 +22,10 @@ class RemoveStatusService < BaseService
 
     return unless @account.local?
 
-    remove_from_mentioned(@stream_entry.reload)
-    Pubsubhubbub::DistributionWorker.perform_async(@stream_entry.id)
+    @stream_entry = @stream_entry.reload
+
+    remove_from_remote_followers
+    remove_from_remote_affected
   end
 
   private
@@ -38,15 +40,48 @@ class RemoveStatusService < BaseService
     end
   end
 
-  def remove_from_mentioned(stream_entry)
-    salmon_xml       = stream_entry_to_xml(stream_entry)
-    target_accounts  = @mentions.map(&:account).reject(&:local?).uniq(&:domain)
+  def remove_from_remote_affected
+    # People who got mentioned in the status, or who
+    # reblogged it from someone else might not follow
+    # the author and wouldn't normally receive the
+    # delete notification - so here, we explicitly
+    # send it to them
+
+    target_accounts = (@mentions.map(&:account).reject(&:local?) + @reblogs.map(&:account).reject(&:local?)).uniq(&:id)
+
+    # Ostatus
+    NotificationWorker.push_bulk(target_accounts.select(&:ostatus?).uniq(&:domain)) do |target_account|
+      [salmon_xml, @account.id, target_account.id]
+    end
+
+    # ActivityPub
+    ActivityPub::DeliveryWorker.push_bulk(target_accounts.select(&:activitypub?).uniq(&:inbox_url)) do |inbox_url|
+      [activity_json, @account.id, inbox_url]
+    end
+  end
+
+  def remove_from_remote_followers
+    # OStatus
+    Pubsubhubbub::DistributionWorker.perform_async(@stream_entry.id)
 
-    NotificationWorker.push_bulk(target_accounts) do |target_account|
-      [salmon_xml, stream_entry.account_id, target_account.id]
+    # ActivityPub
+    ActivityPub::DeliveryWorker.push_bulk(@account.followers.inboxes) do |inbox_url|
+      [activity_json, @account.id, inbox_url]
     end
   end
 
+  def salmon_xml
+    @salmon_xml ||= stream_entry_to_xml(@stream_entry)
+  end
+
+  def activity_json
+    @activity_json ||= ActiveModelSerializers::SerializableResource.new(
+      @status,
+      serializer: ActivityPub::DeleteSerializer,
+      adapter: ActivityPub::Adapter
+    ).to_json
+  end
+
   def remove_reblogs
     # We delete reblogs of the status before the original status,
     # because once original status is gone, reblogs will disappear