Refactor ActivityPub handling to prepare for non-Account actors (#19212)

* Move ActivityPub::FetchRemoteAccountService to ActivityPub::FetchRemoteActorService

ActivityPub::FetchRemoteAccountService is kept as a wrapper for when the actor is
specifically required to be an Account

* Refactor SignatureVerification to allow non-Account actors

* fixup! Move ActivityPub::FetchRemoteAccountService to ActivityPub::FetchRemoteActorService

* Refactor ActivityPub::FetchRemoteKeyService to potentially return non-Account actors

* Refactor inbound ActivityPub payload processing to accept non-Account actors

* Refactor inbound ActivityPub processing to accept activities relayed through non-Account

* Refactor how Account key URIs are built

* Refactor Request and drop unused key_id_format parameter

* Rename ActivityPub::Dereferencer `signature_account` to `signature_actor`

2 files changed, 9 insertions, 5 deletions

diff --git a/app/workers/activitypub/delivery_worker.rb b/app/workers/activitypub/delivery_worker.rb
index 788f2cf80..d9153132b 100644
--- a/app/workers/activitypub/delivery_worker.rb
+++ b/app/workers/activitypub/delivery_worker.rb
@@ -37,7 +37,7 @@ class ActivityPub::DeliveryWorker
 
   def build_request(http_client)
     Request.new(:post, @inbox_url, body: @json, http_client: http_client).tap do |request|
-      request.on_behalf_of(@source_account, :uri, sign_with: @options[:sign_with])
+      request.on_behalf_of(@source_account, sign_with: @options[:sign_with])
       request.add_headers(HEADERS)
       request.add_headers({ 'Collection-Synchronization' => synchronization_header }) if ENV['DISABLE_FOLLOWERS_SYNCHRONIZATION'] != 'true' && @options[:synchronize_followers]
     end
diff --git a/app/workers/activitypub/processing_worker.rb b/app/workers/activitypub/processing_worker.rb
index 37e316354..4d06ad079 100644
--- a/app/workers/activitypub/processing_worker.rb
+++ b/app/workers/activitypub/processing_worker.rb
@@ -5,11 +5,15 @@ class ActivityPub::ProcessingWorker
 
   sidekiq_options backtrace: true, retry: 8
 
-  def perform(account_id, body, delivered_to_account_id = nil)
-    account = Account.find_by(id: account_id)
-    return if account.nil?
+  def perform(actor_id, body, delivered_to_account_id = nil, actor_type = 'Account')
+    case actor_type
+    when 'Account'
+      actor = Account.find_by(id: actor_id)
+    end
 
-    ActivityPub::ProcessCollectionService.new.call(body, account, override_timestamps: true, delivered_to_account_id: delivered_to_account_id, delivery: true)
+    return if actor.nil?
+
+    ActivityPub::ProcessCollectionService.new.call(body, actor, override_timestamps: true, delivered_to_account_id: delivered_to_account_id, delivery: true)
   rescue ActiveRecord::RecordInvalid => e
     Rails.logger.debug "Error processing incoming ActivityPub object: #{e}"
   end