Compact JSON-LD signed incoming activities

app/helpers/jsonld_helper.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 module JsonLdHelper
+  include ContextHelper
+
   def equals_or_includes?(haystack, needle)
     haystack.is_a?(Array) ? haystack.include?(needle) : haystack == needle
   end
@@ -69,6 +71,12 @@ module JsonLdHelper
     graph.dump(:normalize)
   end
 
+  def compact(json)
+    compacted = JSON::LD::API.compact(json.without('signature'), full_context, documentLoader: method(:load_jsonld_context))
+    compacted['signature'] = json['signature']
+    compacted
+  end
+
   def fetch_resource(uri, id, on_behalf_of = nil)
     unless id
       json = fetch_resource_without_id_validation(uri, on_behalf_of)