request.py 文件源码

def get_host(self):
        """Return the HTTP host using the environment or request headers."""
        host = self._get_raw_host()

        # There is no hostname validation when DEBUG=True
        if settings.DEBUG:
            return host

        domain, port = split_domain_port(host)
        if domain and validate_host(domain, settings.ALLOWED_HOSTS):
            return host
        else:
            msg = "Invalid HTTP_HOST header: %r." % host
            if domain:
                msg += " You may need to add %r to ALLOWED_HOSTS." % domain
            else:
                msg += " The domain name provided is not valid according to RFC 1034/1035."
            raise DisallowedHost(msg)