Use rdflib to store rdfa statements
At the moment, we are using rdflib to parse the rdfa metadata. But we are using Json to persist the data on disk.
It would make more sense for me to use rdflib for parsing AND storing the data, using the same database as the django project as the storage backend (eg. MySQL). This is possible with SQLAlchemy plugin for RDFlib.
We would also not be limited index manually chosen metadata but could also store them all.
I believe this would be faster as well.