Thanks guys, both great suggestions. I'll try and get PreCallHook working because that would allow me to add a "pre_put()" method to my Models, and then using these PreCallHooks I can call pre_put() for each of the entities being put into the Datastore.
Failing that, I'll create a new derived property for my Model and do as Devel63 said. 2010/1/15 Devel63 <danstic...@gmail.com> > Nick, > > I've been faced with your exact situation. I have to say I don't > understand PreCallHook, and maybe that would be the best approach, but > here's what I do know. > > Overriding "put" is a bad idea, and as you point out, the override > will not be called in a batch put. > > I found that the most elegant solution was to derive a new type of > db.Property, and override its get_value_for_datastore. Then GAE will > automatically do what you want regardless of how the entity is being > put. > > > On Jan 14, 1:51 am, Eric Ka Ka Ng <ngk...@gmail.com> wrote: > > would a PreCallHook works for your case? > > > > http://code.google.com/appengine/articles/hooks.html > > > > - eric > > > > 2010/1/14 Nickolas Daskalou <n...@daskalou.com>: > > > > > I have a property of a Model that is a hash of another property of the > same > > > Model, eg: > > > > > class MyModel(db.Model): > > > something = db.StringProperty() > > > something_hash = db.StringProperty() > > > def generate_hash(self): > > > self.something_hash = sha1(self.something) > > > > > I want generate_hash() to be automatically called just before the > entity is > > > put() into the Datastore, without the developer having to explicitly > call > > > entity.generate_hash(). > > > > > I know I can create a put() method that makes such a call and then > calls > > > put() on the superclass, but (a) is that the best way to do it, and (b) > if > > > the put() is part of a batch put (eg. via db.put(entities)), will the > put() > > > method of each model instance still be called? > > > > > 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-appengine@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<google-appengine%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > > >--
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