memoize

lib/rack_rubygems.rb

@@ -82,6 +82,7 @@ class RackRubygems < Sinatra::Base
   end
 
   def source_index
+    return @source_index if @source_index
     @gem_dir = Gem.dir
     @spec_dir = File.join @gem_dir, 'specifications'
     @source_index = Gem::SourceIndex.from_gems_in @spec_dir