Change unauthenticated responses to be cached in REST API (#24348)

app/controllers/concerns/api_caching_concern.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module ApiCachingConcern
+  extend ActiveSupport::Concern
+
+  def cache_if_unauthenticated!
+    expires_in(15.seconds, public: true, stale_while_revalidate: 30.seconds, stale_if_error: 1.day) unless user_signed_in?
+  end
+
+  def cache_even_if_authenticated!
+    expires_in(5.minutes, public: true, stale_while_revalidate: 30.seconds, stale_if_error: 1.day) unless whitelist_mode?
+  end
+end