Reject incoming QuoteRequest activities (#34480)

app/lib/activitypub/activity.rb

@@ -57,6 +57,8 @@ class ActivityPub::Activity
         ActivityPub::Activity::Remove
       when 'Move'
         ActivityPub::Activity::Move
+      when 'QuoteRequest'
+        ActivityPub::Activity::QuoteRequest
       end
     end
   end

app/lib/activitypub/activity/quote_request.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+class ActivityPub::Activity::QuoteRequest < ActivityPub::Activity
+  include Payloadable
+
+  def perform
+    return unless Mastodon::Feature.inbound_quotes_enabled?
+    return if non_matching_uri_hosts?(@account.uri, @json['id'])
+
+    quoted_status = status_from_uri(object_uri)
+    return if quoted_status.nil? || !quoted_status.account.local? || !quoted_status.distributable?
+
+    # For now, we don't support being quoted by external servers
+    reject_quote_request!(quoted_status)
+  end
+
+  private
+
+  def reject_quote_request!(quoted_status)
+    quote = Quote.new(
+      quoted_status: quoted_status,
+      quoted_account: quoted_status.account,
+      status: Status.new(account: @account, uri: @json['instrument']),
+      account: @account,
+      activity_uri: @json['id']
+    )
+    json = Oj.dump(serialize_payload(quote, ActivityPub::RejectQuoteRequestSerializer))
+    ActivityPub::DeliveryWorker.perform_async(json, quoted_status.account_id, @account.inbox_url)
+  end
+end