[sqlalchemy] Re: post-populate extension (2)
Also be aware that the API to populate_instance() has changed (ironically,
the very thing that I was worrying about in the thread)
Update this:
def populate_instance(self, mapper, selectcontext, row, instance,
identitykey, isnew):
if isnew:
mapper.populate_instance(selectcontext, instance, row,
identitykey, isnew)
instance.onload()
return None
return EXT_PASS
to this:
def populate_instance(self, mapper, selectcontext, row, instance,
**kwargs):
if kwargs.get('isnew') and hasattr(instance, 'onload'):
mapper.populate_instance(selectcontext, instance, row, **kwargs)
instance.onload()
return None
return EXT_CONTINUE
On Tue, Mar 25, 2008 at 12:57 PM, Michael Bayer [EMAIL PROTECTED]
wrote:
we have a new hook that will be coming soon called something like
__reconstitute__(), which will be called on instances after they've
been created and had their initial population from the result row.
Note that eagerly-loaded collections might not be fully loaded at this
stage.
at the moment the populate_instance() hook is what works in the
current version of 0.4.
On Mar 25, 2008, at 7:05 AM, Nebur wrote:
I'm going to post-populate an instance, and there's a thread which is
exactly about my question but fairly old:
http://groups.google.de/group/sqlalchemy/browse_thread/thread/7467f8e9d86b1749/
Is there a post_populate hook in the current SA 0.4.x, or is Ricks way
(using populate_instance) still the best ?
Ruben
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[sqlalchemy] Re: post-populate extension (2)
we have a new hook that will be coming soon called something like __reconstitute__(), which will be called on instances after they've been created and had their initial population from the result row. Note that eagerly-loaded collections might not be fully loaded at this stage. at the moment the populate_instance() hook is what works in the current version of 0.4. On Mar 25, 2008, at 7:05 AM, Nebur wrote: I'm going to post-populate an instance, and there's a thread which is exactly about my question but fairly old: http://groups.google.de/group/sqlalchemy/browse_thread/thread/7467f8e9d86b1749/ Is there a post_populate hook in the current SA 0.4.x, or is Ricks way (using populate_instance) still the best ? Ruben --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: post-populate extension
Ya, the post_populate hook w/b great -- getting the callback to work was kinda tricky, and I'm worried calling back to internals like that. Calling signatures often change on internals. On 1/25/07, Michael Bayer [EMAIL PROTECTED] wrote: yup that would be how you can do that right now. i mean, I had this vision of SA being used inside of frameworks which would provide their own hooks for these kinds of things, i.e. post- query etc. which is why i dont like to add too many hooks *inside* unless absolutely necessary. but yah if populate_instance() is doing it for you I dont see anything wrong with that(did you want a post_populate_instance() hook or something like that ?) On Jan 24, 2007, at 11:07 PM, Rick Morrison wrote: What's the best way to perfom a bit of manipulation on a mapper-loaded instance just AFTER it's been populated? Right now I'm using a mapper extension to override populate_instance and then calling back to the mapper argument to do the actual population, then adding my changes, but is that the best way? Thx, Rick --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: post-populate extension
ok show me how youre doing it and ill see if i should make something more solid for that. On Jan 25, 2007, at 11:52 AM, Rick Morrison wrote: Ya, the post_populate hook w/b great -- getting the callback to work was kinda tricky, and I'm worried calling back to internals like that. Calling signatures often change on internals. On 1/25/07, Michael Bayer [EMAIL PROTECTED] wrote: yup that would be how you can do that right now. i mean, I had this vision of SA being used inside of frameworks which would provide their own hooks for these kinds of things, i.e. post- query etc. which is why i dont like to add too many hooks *inside* unless absolutely necessary. but yah if populate_instance() is doing it for you I dont see anything wrong with that(did you want a post_populate_instance() hook or something like that ?) On Jan 24, 2007, at 11:07 PM, Rick Morrison wrote: What's the best way to perfom a bit of manipulation on a mapper- loaded instance just AFTER it's been populated? Right now I'm using a mapper extension to override populate_instance and then calling back to the mapper argument to do the actual population, then adding my changes, but is that the best way? Thx, Rick --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: post-populate extension
K, here's a snipppet that shows the populate_instance catch. It's pretty straightforward, but the way that the hook takes (row, instance) in that order, while the callback to the mapper takes (instance, row) got me thinking about calling back to internals and API stability. def populate_instance(self, mapper, selectcontext, row, instance, identitykey, isnew): if isnew: mapper.populate_instance(selectcontext, instance, row, identitykey, isnew) instance.onload() return None return EXT_PASS --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
