Question

I’ve inherited an app which has entity keys stored as strings rather than actual Keys so of course they are not updated by the automatic tool for migration to the HRD datastore.

Can I programmatically (and if so, how) convert the keys stored as strings into strings which represent the new keys for the new app ID? (setting aside the fact that they should not be stored as strings in the first place).

Answer 1

If you are using ndb:

new_key = ndb.Key(urlsafe=string_value_of_key)

and to change the app ID, you can access the protected attribute __app via the public attribute _Key__app

new_key._Key__app = 'new-app-id'

If you are using db:

old_key = db.Key(encoded=string_value_of_key)

Then to convert the key to one with your new app ID, you can use

new_key = db.Key.from_path(*old_key.to_path(), 
                           _app='new-app-id',
                           parent=old_key.parent(), 
                           namespace=old_key.namespace())