python - How to get property from ReferenceProperty class when downloading App Engine data using bulkloader? -

i want download app engine data can operate on efficiently locally (i'm generating pdfs based on it). how can define column referenceproperty gets populated particular property of referenced model rather key or id?

here model classes:

 class department(db.model):    name = db.stringproperty()  class user(db.model):    userkey = db.stringproperty(required=true)    secret = db.stringproperty()    dept = db.referenceproperty(department, required=true) 

however, though have described property_map in bulkloader.yaml so:

 - kind: user   connector: csv   connector_options:   property_map:     - property: __key__       external_name: key       export_transform: transform.key_id_or_name_as_string      - property: dept       external_name: dept       import_transform: transform.create_foreign_key('department')       export_transform: transform.key_id_or_name_as_string      - property: secret       external_name: secret      - property: userkey       external_name: userkey 

i end department key in csv

e.g.

    dept     secret    key 1184017  mysecret  mykey 

how can define dept column gets populated 'name' property of department model?

e.g.

    dept     secret    key mydept  mysecret  mykey 

thanks, paul

create file uploadutil.py , add method in it:

def prop_converter(dept):   # load department return property want   return dept.name 

then add in bulkloader.yaml:

add import uploadutil:

import: uploadutil 

and add property:

- property: dept     external_name: dept     import_transform: transform.create_foreign_key('department')     export_transform: uploadutil.prop_converter 

hence above method called on export!