PairTree is a technique from the digital preservation community for safely mapping identifiers to file paths, and back again. It can be helpful when writing resources to disk so that they can be identified later on by merely looking at the file system layout.
The ptree module has two functions to help you work with PairTree identifiers
and file paths: id2ptree
and ptree2id
.
>>> import ptree
>>> ptree.id2ptree("info:lccn/12345678")
'/in/fo/+l/cc/n=/12/34/56/78/'
>>> ptree.ptree2id('/in/fo/+l/cc/n=/12/34/56/78/')
u'info:lccn/12345678'
ptree draws from Ben O'Steen's PairTree Python module, which provides a lot more functionality for storing bitstreams on disk. For better or worse ptree focuses solely on the identifier/path mapping, and leaves IO operations up to you. The unit tests were shamelessly stolen from John Kunze's File::PairTree.