python - SQLAlchemy "event.listen" para todos los modelos

pylons

Question

Tengo campos created_by y updated_by en cada modelo. Estos campos se llenan automáticamente con sqlalchemy.event.listen (anteriormente MapperExtension). Para cada modelo, escribo:

event.listen(Equipment, ''before_insert'', get_created_by_id)
event.listen(Equipment, ''before_update'', get_updated_by_id)

Cuando el modelo era un montón de código se pone feo. ¿Es posible aplicar event.listen inmediatamente a todos los modelos o a varios?

UPD: estoy tratando de hacerlo:

import pylons
from sqlalchemy import event, sql
from sqlalchemy import Table, ForeignKey, Column
from sqlalchemy.databases import postgresql
from sqlalchemy.schema import UniqueConstraint, CheckConstraint
from sqlalchemy.types import String, Unicode, UnicodeText, Integer, DateTime,/
                             Boolean, Float
from sqlalchemy.orm import relation, backref, synonym, relationship
from sqlalchemy import func
from sqlalchemy import desc
from sqlalchemy.orm.exc import NoResultFound

from myapp.model.meta import Session as s
from myapp.model.meta import metadata, DeclarativeBase

from pylons import request

def created_by(mapper, connection, target):
    identity = request.environ.get(''repoze.who.identity'')
    if identity:
        id = identity[''user''].user_id
        target.created_by = id

def updated_by(mapper, connection, target):
    identity = request.environ.get(''repoze.who.identity'')
    if identity:
        id = identity[''user''].user_id
        target.updated_by = id

from sqlalchemy.ext.declarative import declared_attr
from sqlalchemy.ext.declarative import has_inherited_table

class TestMixin(DeclarativeBase):
    __tablename__ = ''TestMixin''

    id =  Column(Integer, autoincrement=True, primary_key=True)

event.listen(TestMixin, ''before_insert'', created_by)
event.listen(TestMixin, ''before_update'', updated_by)

class MyClass(TestMixin):
    __tablename__ = ''MyClass''
    __mapper_args__ = {''concrete'':True}

    id =  Column(Integer, autoincrement=True, primary_key=True)

    created_by = Column(Integer, ForeignKey(''user.user_id'',
                        onupdate="cascade", ondelete="restrict"))

    updated_by = Column(Integer, ForeignKey(''user.user_id'',
                        onupdate="cascade", ondelete="restrict"))

Cuando agrego un nuevo objeto MyClass, he created_by = None. Si creo event.listen para MyClass todo está bien. ¿Qué pasa?

Answer 1

Hereda todos sus modelos de la clase base y suscríbase a esa clase base:

event.listen(MyBaseMixin, ''before_insert'', get_created_by_id)
event.listen(MyBaseMixin, ''before_update'', get_updated_by_id)

Ver más en Mixin y Custom Base Classes