I've managed to get this going, with the help of the comments in this thread
and Nick Johnson's blog post (
http://blog.notdot.net/2009/11/API-call-hooks-for-fun-and-profit).
My hook code now looks like this:
def hook(service, call, request, response):
assert service == 'datastore_v3'
if call == 'Put':
for i in range(request.entity_size()):
entity_pb = request.mutable_entity(i)
entity = db.model_from_protobuf(entity_pb)
try:
entity.pre_put()
entity_pb.CopyFrom(db.model_to_protobuf(entity))
except:
pass
This seems highly inefficient though, because before an entity is put into
the Datastore, it's converted from a Model instance to an EntityProto
instance, then back to a Model instance and finally back to an EntityProto
instance (Model->EntityProto->Model->EntityProto).
Google guys, is there a more efficient way to do this?
2010/1/18 Nickolas Daskalou <[email protected]>
> Will do, thanks Andy.
>
>
> 2010/1/18 Andy Freeman <[email protected]>
>
>> I asked that question wrt db.class_for_kind and was told that it was
>> safe to assume that it would always be there.
>>
>> I'd guess that model_from_protobuf should be safe as well.
>>
>> File a bug requesting that it be added to the documented function
>> list.
>>
>> On Jan 17, 6:26 pm, Nickolas Daskalou <[email protected]> wrote:
>> > Since these are not documented online anywhere, is it possible these
>> > functions may change in the future (and hence break my code)?
>> >
>> > 2010/1/18 Andy Freeman <[email protected]>
>> >
>> >
>> >
>> > > Search in google/appengine/ext/db/__init__.py for protobuf functions.
>> >
>> > > On Jan 16, 9:21 pm, Nickolas Daskalou <[email protected]> wrote:
>> > > > Does anyone have an answer for this? Google guys?
>> >
>> > > > 2010/1/15 Kapil Kaisare <[email protected]>
>> >
>> > > > > As an aside: what is an EntityProto, and is there a link in the
>> GAE
>> > > > > documentation for it?
>> >
>> > > > > Regards,
>> > > > > Kaisare, Kapil Sadashiv
>> >
>> > > > > On Fri, Jan 15, 2010 at 09:37, Nickolas Daskalou <
>> [email protected]
>> > > >wrote:
>> >
>> > > > >> How can I convert an EntityProto to a Model instance?
>> >
>> > > > >> I have a Model method, pre_put(), that I want to call on each
>> Model
>> > > > >> instance before it's Put into the Datastore, using hooks (eg:
>> > > > >>http://code.google.com/appengine/articles/hooks.html).
>> >
>> > > > >> My hook code looks like this:
>> >
>> > > > >> def hook(service, call, request, response):
>> > > > >> assert service == 'datastore_v3'
>> > > > >> if call == 'Put':
>> > > > >> for entity in request.entity_list():
>> > > > >> entity.pre_put()
>> >
>> > > > >> When the hook is called and runs, I get this error:
>> >
>> > > > >> AttributeError: EntityProto instance has no attribute 'pre_put'
>> >
>> > > > >> Is there any way to convert the entities in request.entity_list()
>> to
>> > > their
>> > > > >> original Models, manipulate them, and then convert them back to
>> an
>> > > > >> EntityProto instance? Or even better, if the EntityProto
>> instances
>> > > have
>> > > > >> references to the actual Model instances which we can access and
>> > > manipulate?
>> >
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