There is currently no proper way to do "re-root" a polymodel the way
you are describing. However, there may be a solution for your
particular problem. I don't know enough about your actual
implementation however you might get away with simply doing a non-
Model based mix-in. So, write your memcache utility class AS IF it
inherits from PolyModel, but don't actually allow it to do so. Like
this:
class CoolFeature(object):
def put(self):
... clear memcache ...
super(CoolFeature, self).put()
Now define your root class:
class MyModel(CoolFeature, polymodel.PolyModel):
...
Here comes the Python lesson, so forgive me if you already know all
this ;)
The key is that you use 'super' correctly and that you have
CoolFeature be the first class your model class inherits from.
'super' allows you to traverse your objects functionality correctly
according to the python "method resolution order". You can see this
order by for any class by studying MyModel.__mro__. This indicates
the order which calls to super will traverse your class definitions.
If you do:
class A(object):
def p(self):
print 'A'
class B(object):
def p(self):
print 'B'
super(B, self).p()
class C(B, A):
def p(self):
print 'C'
super(C, self).p()
...calling C().p() will print:
C
B
A
You should be able to implement whatever functionality you need this
way. Let me know if there are issues with doing that.
On Mar 3, 7:40 pm, Nickolas Daskalou <[email protected]> wrote:
> I should state that I can set the entity kind that's saved in the
> Datastore by adding a kind() method on my "real" models, however the
> class list property of the saved entities still includes the "special"
> PolyModel subclass in it, and I'm not sure if that's a bad thing or
> not.
>
> On Mar 4, 2:16 pm, Nickolas Daskalou <[email protected]> wrote:
>
> > I've been trying to create a "special" subclass of PolyModel (that does cool
> > stuff like update Memcache after an entity put()) which my polymodel models
> > can inherit from (instead of inheriting from db.polymodel.PolyModel).
>
> > This has the nasty side effect though of making that "special" subclass of
> > PolyModel the root class for my polymodel models.
>
> > Is there a way around this?
>
> > Eg. Telling db.polymodel.PolyModel to NOT include the first direct subclass
> > in the class hierarchy that is saved to the Datastore? Or writing my own
> > PolyModel by basically copying db.polymodel and changing code where
> > appropriate?
>
> > Appreciate any help.
>
> > Nick
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