An OCSP POST request contains the DER encoded OCSP request in the HTTP
        request body.

def _handle_post(self):
        """
        An OCSP POST request contains the DER encoded OCSP request in the HTTP
        request body.
        """
        der = request.body.read()
        ocsp_request = self._parse_ocsp_request(der)
        return self._build_http_response(ocsp_request)