Thanks for your reply Rafe. Using non-Model mix-ins seems like the way to go.
As with many App Engine developers, my Python experience is equivalent to my App Engine experience, so I appreciated the Python lesson ;) Nick On 5 March 2010 08:52, Rafe <slobberch...@gmail.com> wrote: > 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 <n...@daskalou.com> 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 <n...@daskalou.com> 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 > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to google-appeng...@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com<google-appengine%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appeng...@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
