Process the request before routing it.

def process_request(self, req, resp):  # pylint: disable=unused-argument
        """ Process the request before routing it. """

        try:
            creds = self._get_creds(req)
            self.auth_creds(*creds)
        except (AuthRejected, AuthRequired, InvalidAuthSyntax) as exc:
            exc.headers = self._error_headers
            if not self.optional:
                abort(exc)