    def xsrf_token(self):
        """Override tornado's xsrf token with further restrictions

        - only set cookie for regular pages
        - include login info in xsrf token
        - verify signature
        """
        return get_xsrf_token(self, cookie_path=self.hub.base_url)
Override tornado's xsrf token with further restrictions

- only set cookie for regular pages
- include login info in xsrf token
- verify signature
jupyterhub/handlers/base.py