How does pip detect URL of archive if version of package is not provided?

Question

When you run pip install somepackage , pip downloads the latest version of somepackage .

All archives on PYPI have names like somepackage-XXtar.gz . How does pip know what X s are? Ie how does it detect the URL of the archive to download?

Answer 1

I believe PIP relies on the containing directory being readable/listable. It then uses that directory listing to know all versions of the package, it's then easy to work out what the latest version is.

For example: https://pypi.python.org/packages/source/D/Django/