request.py 文件源码

def get_host(self):
        """Returns the HTTP host using the environment or request headers."""
        # We try three options, in order of decreasing preference.
        if settings.USE_X_FORWARDED_HOST and (
                'HTTP_X_FORWARDED_HOST' in self.META):
            host = self.META['HTTP_X_FORWARDED_HOST']
        elif 'HTTP_HOST' in self.META:
            host = self.META['HTTP_HOST']
        else:
            # Reconstruct the host using the algorithm from PEP 333.
            host = self.META['SERVER_NAME']
            server_port = str(self.META['SERVER_PORT'])
            if server_port != ('443' if self.is_secure() else '80'):
                host = '%s:%s' % (host, server_port)

        # 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)