Question

A string representation of entity’s key always have app-id & namespace as a prefix. But in most case they are not required because too obvious.

ex> Key :
ag13YXJjbG91ZC10ZXN0chsLEgVGb3JjZRihnAEMCxIIVW5pdFNsb3QYAgw

after removing appid_namespace part :
chsLEgVGb3JjZRihnAEMCxIIVW5pdFNsb3QYAgw

I know (kind,id or name) pair can be another solution for identifying unique entity but here, I just want to know how to eliminate app-id & namespace prefix and expose rest as a part of REST API…

How can I remove them?

Answer 1

Hey, I’m not sure how you want your REST api to work, but if you do something like

from google.appengine.ext import db

def getRESTPath (entity):
    def addKeyPathRecursive (key):
        restPaths.append('%s/%s' % (key.kind(), key.id_or_name()))
        parentKey = key.parent()
        if parentKey:
            addKeyPathRecursive(parentKey)
    restPaths = []
    addKeyPathRecursive(entity.key())
    return '/'.join(reversed(restPaths))

class Grandpa(db.Model): pass
class Papa(db.Model): pass
class Kid(db.Model): pass

kid = Kid(parent = Papa(parent = Grandpa().put()).put())
kid.put()
print getRESTPath(kid)

you get a string like Grandpa/21386/Papa/21387/Kid/21388.

If you just want (kind, id_or_name) without the ancestor path, I’m not sure why you’re unhappy with '%s/%s' % (key.kind(), key.id_or_name()). You can’t remove namespace info from the way the datastore treats keys internally, but that doesn’t mean you have to display it to users.