main.py 文件源码

def download(url, target, expected_hash):
    if filesystem.calculate_hash(target) == expected_hash:
        return
    count = 0

    while filesystem.calculate_hash(TEMP_FILE) != expected_hash:
        count += 1
        if count > 5:
            os.remove(TEMP_FILE)
            raise OSError("Aborting download of %s after 5 unsuccessful attempts" % url)
        try:
            http_client.get(url).raise_for_status().download_to(TEMP_FILE)
        except OSError:
            pass

    # If it already exists the rename will fail
    try:
        os.remove(target)
    except OSError:
        pass
    os.rename(TEMP_FILE, target)