# File lib/fog/storage/models/aws/file.rb, line 91
        def public_url
          requires :directory, :key
          if connection.get_object_acl(directory.key, key).body['AccessControlList'].detect {|grant| grant['Grantee']['URI'] == 'http://acs.amazonaws.com/groups/global/AllUsers' && grant['Permission'] == 'READ'}
            if directory.key.to_s =~ /^(?:[a-z]|\d(?!\d{0,2}(?:\.\d{1,3}){3}$))(?:[a-z0-9]|\.(?![\.\-])|\-(?![\.])){1,61}[a-z0-9]$/
              "https://#{directory.key}.s3.amazonaws.com/#{key}"
            else
              "https://s3.amazonaws.com/#{directory.key}/#{key}"
            end
          else
            nil
          end
        end