socket.py 文件源码

def gethostbyname(hostname):
        """:func:`socket.gethostbyname` implemented using :mod:`gevent.dns`.

        Differs in the following ways:

        * raises :class:`DNSError` (a subclass of :class:`socket.gaierror`) with dns error
          codes instead of standard socket error codes
        * does not support ``/etc/hosts`` but calls the original :func:`socket.gethostbyname`
          if *hostname* has no dots
        * does not iterate through all addresses, instead picks a random one each time
        """
        # TODO: this is supposed to iterate through all the addresses
        # could use a global dict(hostname, iter)
        # - fix these nasty hacks for localhost, ips, etc.
        if not isinstance(hostname, str) or '.' not in hostname:
            return _socket.gethostbyname(hostname)
        if _ip4_re.match(hostname):
            return hostname
        if hostname == _socket.gethostname():
            return _socket.gethostbyname(hostname)
        addrs = None
        try:
            _ttl, addrs = resolve_ipv4(hostname)
        except:
            _ttl, addrs = resolve_ipv6(hostname)
            return inet_ntop(AF_INET6, random.choice(addrs))
        else:
            return inet_ntop(AF_INET, random.choice(addrs))