Make relationship and fk args customizable

* Add configuration option for relationship args
* Add foreign_key_args parameter to translation_base function

CHANGES.rst

@@ -4,6 +4,13 @@ Changelog
 Here you can see the full list of changes between each SQLAlchemy-i18n release.
 
 
+1.0.2 (2016-03-06)
+^^^^^^^^^^^^^^^^^^
+
+- Added ``translations_relationship_args`` configuration option
+- Added ``foreign_key_args`` parameter to ``translations_base`` function
+
+
 1.0.1 (2014-10-21)
 ^^^^^^^^^^^^^^^^^^
 

docs/config.rst

@@ -75,3 +75,31 @@ Other options
 * fallback_locale
 
     The locale which will be used as a fallback for translation hybrid properties that return None or empty string.
+
+* translations_relationship_args
+
+    Dictionary of arguments passed as defaults for automatically created translations relationship.::
+
+
+    class Article(Base):
+        __tablename__ = 'article'
+        __translatable__ = {
+            'locales': [u'en', u'fi'],
+            'translations_relationship_args': {
+                'passive_deletes': False
+            }
+        }
+
+        id = sa.Column(sa.Integer, primary_key=True, autoincrement=True)
+
+        author = sa.Column(sa.Unicode(255))
+
+        def get_locale(self):
+            return 'en'
+
+
+    class ArticleTranslation(translation_base(Article)):
+        __tablename__ = 'article_translation'
+
+        name = sa.Column(sa.Unicode(255))
+        content = sa.Column(sa.UnicodeText)

sqlalchemy_i18n/__init__.py

@@ -14,7 +14,7 @@
 )
 
 
-__version__ = '1.0.1'
+__version__ = '1.0.2'
 
 
 def make_translatable(

sqlalchemy_i18n/builders.py

@@ -1,3 +1,5 @@
+from copy import copy
+
 import sqlalchemy as sa
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.orm.collections import attribute_mapped_collection
@@ -95,7 +97,8 @@ def __call__(self):
 
 
 class RelationshipBuilder(object):
-    def __init__(self, translation_cls):
+    def __init__(self, manager, translation_cls):
+        self.manager = manager
         self.translation_cls = translation_cls
         self.parent_cls = self.translation_cls.__parent_class__
 
@@ -180,21 +183,35 @@ def assign_translations(self):
         """
         mapper = sa.orm.class_mapper(self.parent_cls)
         if not mapper.has_property('_translations'):
-            foreign_keys = [
-                getattr(self.translation_cls, column_key)
-                for column_key in get_primary_keys(self.parent_cls).keys()
-            ]
-
             mapper.add_property('_translations', sa.orm.relationship(
                 self.translation_cls,
-                primaryjoin=sa.and_(*self.primary_key_conditions),
-                foreign_keys=foreign_keys,
-                collection_class=attribute_mapped_collection('locale'),
-                comparator_factory=TranslationComparator,
-                cascade='all, delete-orphan',
-                passive_deletes=True,
+                **self.get_translations_relationship_args()
             ))
 
+    def get_translations_relationship_args(self):
+        foreign_keys = [
+            getattr(self.translation_cls, column_key)
+            for column_key in get_primary_keys(self.parent_cls).keys()
+        ]
+
+        relationship_args = copy(
+            self.manager.option(
+                self.parent_cls,
+                'translations_relationship_args'
+            )
+        )
+        defaults = dict(
+            primaryjoin=sa.and_(*self.primary_key_conditions),
+            foreign_keys=foreign_keys,
+            collection_class=attribute_mapped_collection('locale'),
+            comparator_factory=TranslationComparator,
+            cascade='all, delete-orphan',
+            passive_deletes=True,
+        )
+        for key, value in defaults.items():
+            relationship_args.setdefault(key, value)
+        return relationship_args
+
     def assign_translation_parent(self):
         mapper = sa.orm.class_mapper(self.translation_cls)
         if not mapper.has_property('translation_parent'):

sqlalchemy_i18n/manager.py

@@ -12,10 +12,18 @@ class BaseTranslationMixin(object):
     pass
 
 
-def translation_base(parent_cls, base_class_factory=None):
+def translation_base(
+    parent_cls,
+    base_class_factory=None,
+    foreign_key_args=None
+):
     if base_class_factory is None:
         base_class_factory = get_declarative_base
 
+    if foreign_key_args is None:
+        foreign_key_args = {}
+        foreign_key_args.setdefault('ondelete', 'CASCADE')
+
     class TranslationMixin(
         base_class_factory(parent_cls),
         BaseTranslationMixin
@@ -37,7 +45,7 @@ def __table_args__(cls):
                             '%s.%s' % (parent_cls.__tablename__, name)
                             for name in names
                         ],
-                        ondelete='CASCADE'
+                        **foreign_key_args
                     ),
                 )
 
@@ -64,7 +72,8 @@ def __init__(self):
             'locales': [],
             'auto_create_locales': True,
             'fallback_locale': 'en',
-            'exclude_hybrid_properties': []
+            'exclude_hybrid_properties': [],
+            'translations_relationship_args': {}
         }
 
     def instrument_translation_classes(self, mapper, cls):
@@ -96,7 +105,7 @@ def configure_translatable_classes(self):
             parent_cls.__translatable__['class'] = cls
 
             HybridPropertyBuilder(self, cls)()
-            RelationshipBuilder(cls)()
+            RelationshipBuilder(self, cls)()
 
         self.pending_classes = []
 

tests/test_configuration.py

@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+
+import sqlalchemy as sa
+
+from sqlalchemy_i18n import Translatable, translation_base
+from tests import DeclarativeTestCase
+
+
+class TestTranslationBaseCustomization(DeclarativeTestCase):
+    def create_models(self):
+        class Article(self.Model, Translatable):
+            __tablename__ = 'article'
+            __translatable__ = {
+                'locales': ['fi', 'en'],
+                'auto_create_locales': True,
+                'translations_relationship_args': {
+                    'collection_class': list,
+                }
+            }
+
+            id = sa.Column(sa.Integer, primary_key=True)
+
+            locale = 'en'
+
+        TranslationBase = translation_base(
+            Article,
+            foreign_key_args={'onupdate': 'SET NULL'}
+        )
+
+        class ArticleTranslation(TranslationBase):
+            __tablename__ = 'article_translation'
+
+            name = sa.Column(sa.Unicode(255))
+
+        self.Article = Article
+        self.ArticleTranslation = ArticleTranslation
+
+    def test_customize_foreign_key_args(self):
+        assert (
+            self.ArticleTranslation.__table__.foreign_keys.pop().onupdate ==
+            'SET NULL'
+        )
+
+    def test_customize_relationships_args(self):
+        assert self.Article._translations.property.collection_class == list