Thanks for the reply! I'll add the info property. Glad to see I wasn't
going about this completely the wrong way
On Sun, Feb 23, 2014 at 1:16 PM, Michael Bayer <mike...@zzzcomputing.com>wrote:
>
> On Feb 23, 2014, at 12:59 AM, Josh Kuhn <deontologic...@gmail.com> wrote:
>
> > I'm writing some code to serialize some SA models to JSON, and for
> columns and relationships, it's convenient to tag which fields should be
> serialized with the info dictionary like so:
> >
> > class Thing(Base):
> > id = Column(Integer, primary_key=True, info={'jsonify': False})
> > name = Column(String, info={'jsonify': True})
> > relationship(SomeModel, info={'jsonify': True}
> >
> > Then in the Base class, you can iterate over properties like:
> >
> > for attr, column in inspect(self.__class__).columns.items():
> > if column.info.get('jsonify', False):
> > json_output[attr] = getattr(self, attr)
> > for attr, rel in inspect(self.__class__).relationships.items():
> > # similar, with some recursion depending on rel.uselist etc...
> >
> > But for association_proxies, there is no info property, nor is there any
> mapper.association_proxies attribute.
> >
> > I can obviously hack around this in some way, but I'm wondering if I'm
> going about it wrong. Is the best way to get the association_proxies from
> the mapper to filter through .all_orm_descriptors?
>
> yes, from that point of view an association proxy is in a different class
> of attribute than something like a column or relationship. The hierarchy
> of “attributes that are mapped” is called MapperProperty. Association
> proxy isn’t in that hierarchy, but the .all_orm_descriptors collection was
> added so that things like hybrid attributes and association proxies can be
> found, based on their membership in the much more general “_InspectionAttr”
> hierarchy.
>
> >
> > Also, why don't association_proxies have an info property?
>
> no particular reason. Do you think .info would be independent of the
> .info that’s present on the proxies attributes? Or it could have a copy
> (or be the same collection) as that of the “left” or “right” attributes its
> proxying (probably not though). Perhaps we’d want to have .info,
> .local_info, .remote_info. It might be something that we just want to
> stick on the base “_InsepctionAttr” so that everything gets an info, hybrid
> attributes, etc.
>
>
> >
> > What would be the recommended way to do this kind of annotation on the
> models for json serialization?
>
> Probably assume we’ll add .info to these attributes and for now just tack
> an .info dictionary onto your association proxy.
>
> I’ve added
> https://bitbucket.org/zzzeek/sqlalchemy/issue/2971/move-info-from-mapperproperty-down-tofor
> that.
>
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