venv/lib/python3.8/site-packages/pip/_internal/models/index.py

from pip._vendor.six.moves.urllib import parse as urllib_parse


class PackageIndex(object):
    """Represents a Package Index and provides easier access to endpoints
    """

    __slots__ = ['url', 'netloc', 'simple_url', 'pypi_url',
                 'file_storage_domain']

    def __init__(self, url, file_storage_domain):
        # type: (str, str) -> None
        super(PackageIndex, self).__init__()
        self.url = url
        self.netloc = urllib_parse.urlsplit(url).netloc
        self.simple_url = self._url_for_path('simple')
        self.pypi_url = self._url_for_path('pypi')

        # This is part of a temporary hack used to block installs of PyPI
        # packages which depend on external urls only necessary until PyPI can
        # block such packages themselves
        self.file_storage_domain = file_storage_domain

    def _url_for_path(self, path):
        # type: (str) -> str
        return urllib_parse.urljoin(self.url, path)


PyPI = PackageIndex(
    'https://pypi.org/', file_storage_domain='files.pythonhosted.org'
)
TestPyPI = PackageIndex(
    'https://test.pypi.org/', file_storage_domain='test-files.pythonhosted.org'
)