'Attempt to fetch mapping from the data server.'

def _FetchMapping(self):

    try:
        self.conn.request('POST', '/client/mapping')
        res = self.conn.getresponse()
        if (res.status != constants.RESPONSE_OK):
            return None
        return res.read()
    except httplib.HTTPException:
        logging.warning('Could    not    connect    server    %s:%d', self.Address(), self.Port())
        return None
