Hi,
we should provide a way to retrieve [Commons license & author] easily.
This is tracked at [[bugzilla:17503]]
Though it is not as good as what you are looking for, license is well exposed through HTML elements. Author is as well (but fail in many cases).
Some external tools already rely on this machine readable data. More information at [2].
-- Jean-Frédéric
[1] https://bugzilla.wikimedia.org/show_bug.cgi?id=17503 [2] https://commons.wikimedia.org/wiki/Commons:Machine-readable_data