download.py 文件源码

def unpack_http_url(link, location, download_dir=None,
                    session=None, hashes=None):
    if session is None:
        raise TypeError(
            "unpack_http_url() missing 1 required keyword argument: 'session'"
        )

    temp_dir = tempfile.mkdtemp('-unpack', 'pip-')

    # If a download dir is specified, is the file already downloaded there?
    already_downloaded_path = None
    if download_dir:
        already_downloaded_path = _check_download_dir(link,
                                                      download_dir,
                                                      hashes)

    if already_downloaded_path:
        from_path = already_downloaded_path
        content_type = mimetypes.guess_type(from_path)[0]
    else:
        # let's download to a tmp dir
        from_path, content_type = _download_http_url(link,
                                                     session,
                                                     temp_dir,
                                                     hashes)

    # unpack the archive to the build dir location. even when only downloading
    # archives, they have to be unpacked to parse dependencies
    unpack_file(from_path, location, content_type, link)

    # a download dir is specified; let's copy the archive there
    if download_dir and not already_downloaded_path:
        _copy_file(from_path, download_dir, link)

    if not already_downloaded_path:
        os.unlink(from_path)
    rmtree(temp_dir)