setup.py 文件源码

def download_setuptools(packagename, to_dir):
    # making sure we use the absolute path
    to_dir = os.path.abspath(to_dir)
    try:
        from urllib.request import urlopen
    except ImportError:
        from urllib2 import urlopen

    chksum, url = get_pypi_src_download(packagename)
    tgz_name = os.path.basename(url)
    saveto = os.path.join(to_dir, tgz_name)

    src = dst = None
    if not os.path.exists(saveto):  # Avoid repeated downloads
        try:
            log.warn("Downloading %s", url)
            src = urlopen(url)
            # Read/write all in one block, so we don't create a corrupt file
            # if the download is interrupted.
            data = src.read()

            if chksum is not None:
                data_sum = md5(data).hexdigest()
                if data_sum != chksum:
                    raise RuntimeError("Downloading %s failed: corrupt checksum"%(url,))


            dst = open(saveto, "wb")
            dst.write(data)
        finally:
            if src:
                src.close()
            if dst:
                dst.close()
    return os.path.realpath(saveto)