ez_setup.py 文件源码

def _resolve_version(version):
    """
    Resolve LATEST version
    """
    if version is not LATEST:
        return version

    meta_url = urljoin(DEFAULT_URL, '/pypi/setuptools/json')
    resp = urlopen(meta_url)
    with contextlib.closing(resp):
        try:
            charset = resp.info().get_content_charset()
        except Exception:
            # Python 2 compat; assume UTF-8
            charset = 'UTF-8'
        reader = codecs.getreader(charset)
        doc = json.load(reader(resp))

    return str(doc['info']['version'])