X-Git-Url: http://git.veekun.com/zzz-pokedex.git/blobdiff_plain/383eac97a0a1ebe61787b3276b675222826ba6ef..2c94dcb72535499c43958ceb9d1ca6af25740995:/pokedex/db/multilang.py?ds=sidebyside diff --git a/pokedex/db/multilang.py b/pokedex/db/multilang.py index 96d70d6..dcbe489 100644 --- a/pokedex/db/multilang.py +++ b/pokedex/db/multilang.py @@ -3,13 +3,14 @@ from functools import partial 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 from sqlalchemy.types import Integer def create_translation_table(_table_name, foreign_class, relation_name, - language_class, **kwargs): + language_class, relation_lazy='select', **kwargs): """Creates a table that represents some kind of data attached to the given foreign class, but translated across several languages. Returns the new table's mapped class. It won't be declarative, but it will have a @@ -17,7 +18,6 @@ def create_translation_table(_table_name, foreign_class, relation_name, `foreign_class` must have a `__singlename__`, currently only used to create the name of the foreign key column. -TODO remove this requirement Also supports the notion of a default language, which is attached to the session. This is English by default, for historical and practical reasons. @@ -69,22 +69,19 @@ TODO remove this requirement # want to create tables entirely separate from the pokedex metadata foreign_key_name = foreign_class.__singlename__ + '_id' - # A foreign key "language_id" will clash with the language_id we naturally - # put in every table. Rename it something else - if foreign_key_name == 'language_id': - # TODO change language_id below instead and rename this - foreign_key_name = 'lang_id' Translations = type(_table_name, (object,), { - '_language_identifier': association_proxy('language', 'identifier'), + '_language_identifier': association_proxy('local_language', 'identifier'), }) # 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), - Column('language_id', Integer, ForeignKey(language_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, + info=dict(description="Language these texts are in")), ) Translations.__table__ = table @@ -99,14 +96,11 @@ TODO remove this requirement # Construct ye mapper mapper(Translations, table, properties={ - # TODO change to foreign_id - 'object_id': synonym(foreign_key_name), - # TODO change this as appropriate - 'language': relationship(language_class, - primaryjoin=table.c.language_id == language_class.id, - lazy='joined', - innerjoin=True), - # TODO does this need to join to the original table? + 'foreign_id': synonym(foreign_key_name), + 'local_language': relationship(language_class, + primaryjoin=table.c.local_language_id == language_class.id, + innerjoin=True, + lazy='joined'), }) # Add full-table relations to the original class @@ -114,31 +108,27 @@ TODO remove this requirement setattr(foreign_class, relation_name + '_table', Translations) # Foo.bars setattr(foreign_class, relation_name, relationship(Translations, - primaryjoin=foreign_class.id == Translations.object_id, - collection_class=attribute_mapped_collection('language'), - # TODO - lazy='select', + primaryjoin=foreign_class.id == Translations.foreign_id, + collection_class=attribute_mapped_collection('local_language'), )) # 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.object_id, - Translations.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, - # TODO MORESO HERE - lazy='select', + #innerjoin=True, + lazy=relation_lazy, )) # Add per-column proxies to the original class @@ -152,22 +142,56 @@ TODO remove this requirement # these are passed as *args anyway def creator(language, value): row = Translations() - row.language = language + row.local_language = language setattr(row, name, value) return row 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' + _default_language_id = 9 # English. XXX magic constant + + @property + def default_language(self): + # XXX need to get the right mapped class for this to work + raise NotImplementedError + + @default_language.setter + def default_language(self, new): + self._default_language_id = new#.id + + @default_language.deleter + def default_language(self): + try: + del self._default_language_id + except AttributeError: + pass 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.""" + + @property + def default_language(self): + return self.registry().default_language + + @default_language.setter + def default_language(self, new): + self.registry().default_language = new + + def remove(self): + del self.registry().default_language + super(MultilangScopedSession, self).remove()