def create_presence(role_id, place_id):
''' create a Presence for a Role in a Place '''
profile = _get_my_profile()
if is_present(role_id, place_id):
raise ActionException('Role is already present')
role = _get_role(role_id)
place = _get_place(place_id)
pkey = db.Key(Profile, profile.key.id(), Place, place.key.id(), Presence, role.name)
presence = pkey.get()
if presence is None:
presence = Presence(id=role.name, parent=place.key)
presence.role = role.key
presence.put()
return presence.key.urlsafe()
def delete_role(role_id):
''' delete a Role as long as it is not Present in a Place '''
if len(Presence.query(Presence.role == db.Key(urlsafe=role_id)).fetch()) > 0:
raise ActionException('Role still has presence')
db.Key(urlsafe=role_id).delete()
def _get_presences(place_id):
place = db.Key(urlsafe=place_id)
return [presence for presence in Presence.query(ancestor=place).fetch()]
