decode_csrf_token

# File actionpack/lib/action_controller/metal/request_forgery_protection.rb, line 535
      def decode_csrf_token(encoded_csrf_token) # :nodoc:
        if urlsafe_csrf_tokens
          Base64.urlsafe_decode64(encoded_csrf_token)
        else
          begin
            Base64.strict_decode64(encoded_csrf_token)
          rescue ArgumentError
            Base64.urlsafe_decode64(encoded_csrf_token)
          end
        end
      end