django - Ndb models: assure uniqueness in datastore using custom key_name -

i'm trying mimic django's unique_together feature, can't seem straight

class myclass(ndb.model):     name = 'name'     surname = 'surname'     phone = 'phone'      def get_unique_key(self):         return self.name + "|" + self.surname + "|" + self.phone 

"yeah, pretty easy" not

according accepted answer in this post, assigning id param in obj constructor enough. don't want handle in view. ideally, i'd this:

object = myclass() object = object.custom_populating_method(form.cleaned_data) object.id = object.get_unique_key() object.put() 

or better, place in _pre_put_hook, id set last thing before saving (and maybe checking enforcing uniqueness of data across datastore).

apparently, wrong. way achieve hacking view:

unique_id = "|" + form.cleaned_data['bla'] + "|" + form.cleaned_data ... object = myclass(id=unique_id) 

which awful , wrong (since every change model's requirements needs inspected in views). plus, i'd end doing couple of ugly calls fetch related data. i've spent time, probably, on problem see exit , hope i'm missing obvious here, can't find example nor proper documentation around subject. has hint or experience similar?

tl;dr: there nice way achieve without adding unnecessary code views?

(i'm "using" django , ndb's models on datastore)

thanks

use factory or class method construct instance.

class myclass(ndb.model):     name = ndb.stringproperty()     surname = ndb.stringproperty()     phone = ndb.stringproperty()      @staticmethod     def get_unique_key(name,surname,phone):         return '|'.join((name,surname,phone))      @classmethod     @transactional     def create_entity(cls,keyname,name,surname,phone):         key = ndb.key(cls, cls.get_uniquekey())         ent = key.get()         if ent:              raise someduplicateerror()          else:             ent = cls(key=key, name=name,surname=surname,phone=phone)             ent.put() 

newobj = myclass.create_entity(somename, somesurname, somephone)

doing way allows ensure key unique creatin key , tring fetch first.