from sqlalchemy.ext.associationproxy import association_proxy
from sqlalchemy.orm import aliased, compile_mappers, mapper, relationship, synonym
from sqlalchemy.orm.collections import attribute_mapped_collection
+from sqlalchemy.orm.scoping import ScopedSession
from sqlalchemy.orm.session import Session, object_session
from sqlalchemy.schema import Column, ForeignKey, Table
from sqlalchemy.sql.expression import and_, bindparam, select
# Create the table object
table = Table(_table_name, foreign_class.__table__.metadata,
Column(foreign_key_name, Integer, ForeignKey(foreign_class.id),
- primary_key=True, nullable=False),
+ primary_key=True, nullable=False,
+ info=dict(description="ID of the %s these texts relate to" % foreign_class.__singlename__)),
Column('local_language_id', Integer, ForeignKey(language_class.id),
- primary_key=True, nullable=False),
+ primary_key=True, nullable=False,
+ info=dict(description="Language these texts are in")),
)
Translations.__table__ = table
'foreign_id': synonym(foreign_key_name),
'local_language': relationship(language_class,
primaryjoin=table.c.local_language_id == language_class.id,
- lazy='joined',
- innerjoin=True),
+ innerjoin=True,
+ lazy='joined'),
})
# Add full-table relations to the original class
))
# Foo.bars_local
# This is a bit clever; it uses bindparam() to make the join clause
- # modifiable on the fly. db sessions know the current language identifier
- # populates the bindparam. The manual alias and join are (a) to make the
- # condition nice (sqla prefers an EXISTS) and to make the columns play nice
- # when foreign_class == language_class.
+ # modifiable on the fly. db sessions know the current language and
+ # populate the bindparam.
+ # The 'dummy' value is to trick SQLA; without it, SQLA thinks this
+ # bindparam is just its own auto-generated clause and everything gets
+ # fucked up.
local_relation_name = relation_name + '_local'
- language_class_a = aliased(language_class)
setattr(foreign_class, local_relation_name, relationship(Translations,
primaryjoin=and_(
- foreign_class.id == Translations.foreign_id,
- Translations.local_language_id == select(
- [language_class_a.id],
- language_class_a.identifier ==
- bindparam('_default_language', required=True),
- ),
+ Translations.foreign_id == foreign_class.id,
+ Translations.local_language_id == bindparam('_default_language_id',
+ value='dummy', type_=Integer, required=True),
),
+ foreign_keys=[Translations.foreign_id, Translations.local_language_id],
uselist=False,
#innerjoin=True,
lazy=relation_lazy,
setattr(foreign_class, name + '_map',
association_proxy(relation_name, name, creator=creator))
+ # Add to the list of translation classes
+ foreign_class.translation_classes.append(Translations)
+
# Done
return Translations
class MultilangSession(Session):
- """A tiny Session subclass that adds support for a default language."""
- default_language = 'en'
+ """A tiny Session subclass that adds support for a default language.
+
+ Needs to be used with `MultilangScopedSession`, below.
+ """
+ default_language_id = None
+
+ def __init__(self, *args, **kwargs):
+ if 'default_language_id' in kwargs:
+ self.default_language_id = kwargs.pop('default_language_id')
+
+ super(MultilangSession, self).__init__(*args, **kwargs)
def execute(self, clause, params=None, *args, **kwargs):
if not params:
params = {}
- params.setdefault('_default_language', self.default_language)
+ params.setdefault('_default_language_id', self.default_language_id)
+
return super(MultilangSession, self).execute(
clause, params, *args, **kwargs)
+
+class MultilangScopedSession(ScopedSession):
+ """Dispatches language selection to the attached Session."""
+
+ def __init__(self, *args, **kwargs):
+ super(MultilangScopedSession, self).__init__(*args, **kwargs)
+
+ @property
+ def default_language_id(self):
+ """Passes the new default language id through to the current session.
+ """
+ return self.registry().default_language_id
+
+ @default_language_id.setter
+ def default_language_id(self, new):
+ self.registry().default_language_id = new