psdns.py 文件源码

def dns_bulk_resolve(candidates, reverse=False, ip_version=None, threads=50):
    """
    Resolve a list of host names to IPs or, if reverse is true, IPs to
    host names.  Return a map of each result keyed to its candidate.

    WARNING: This function will create a pool of up to 'threads'
    threads.
    """

    # This is based loosely on http://stackoverflow.com/a/34377198

    if reverse and ip_version is not None:
        raise ValueError("Unable to force IP version when reverse-resolving")

    if ip_version is None:
        ip_version = 4
    __check_ip_version__(ip_version)

    result = {}

    if len(candidates) == 0:
        return result

    # Work around a bug in 2.6
    # TODO: Get rid of this when 2.6 is no longer in the picture.
    if not hasattr(threading.current_thread(), "_children"):
        threading.current_thread()._children = weakref.WeakKeyDictionary()

    pool = multiprocessing.dummy.Pool(
        processes=min(len(candidates), threads) )

    candidate_args = [ (candidate, ip_version) for candidate in candidates ]

    for ip, name in pool.imap(
        __reverser__ if reverse else __forwarder__,
        candidate_args,
        chunksize=1):
        result[ip] = name
    pool.close()
    return result