Commit c8873bbb authored by Russell Keith-Magee's avatar Russell Keith-Magee
Browse files

Made the database master router tolerant of router definitions that omit... 

Made the database master router tolerant of router definitions that omit individual routing methods.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12304 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent b0d218e9

django/db/utils.py

+21 −9
Original line number Diff line number Diff line
@@ -103,9 +103,13 @@ class ConnectionRouter(object): 
        def _route_db(self, model, **hints):

            chosen_db = None

            for router in self.routers:

                try:

                    chosen_db = getattr(router, action)(model, **hints)

                    if chosen_db:

                        return chosen_db

                except AttributeError:

                    # If the router doesn't have a method, skip to the next one.

                    pass

            try:

                return hints['instance']._state.db or DEFAULT_DB_ALIAS

            except KeyError:
@@ -117,14 +121,22 @@ class ConnectionRouter(object): 


    def allow_relation(self, obj1, obj2, **hints):

        for router in self.routers:

            try:

                allow = router.allow_relation(obj1, obj2, **hints)

                if allow is not None:

                    return allow

            except AttributeError:

                # If the router doesn't have a method, skip to the next one.

                pass

        return obj1._state.db == obj2._state.db



    def allow_syncdb(self, db, model):

        for router in self.routers:

            try:

                allow = router.allow_syncdb(db, model)

                if allow is not None:

                    return allow

            except AttributeError:

                # If the router doesn't have a method, skip to the next one.

                pass

        return True

docs/topics/db/multi-db.txt

+5 −1
Original line number Diff line number Diff line
@@ -99,7 +99,7 @@ routing scheme. 
Database routers

----------------



A database Router is a class that provides four methods:

A database Router is a class that provides up to four methods:



.. method:: db_for_read(model, **hints)
@@ -141,6 +141,10 @@ A database Router is a class that provides four methods: 
    the router has no opinion. This method can be used to determine

    the availability of a model on a given database.



A router doesn't have to provide *all* these methods - it omit one or

more of them. If one of the methods is omitted, Django will skip that

router when performing the relevant check.



.. _topics-db-multi-db-hints:



Hints

tests/regressiontests/multiple_database/tests.py

+36 −0
Original line number Diff line number Diff line
@@ -674,6 +674,11 @@ class AuthRouter(object): 
            return False

        return None



class WriteRouter(object):

    # A router that only expresses an opinion on writes

    def db_for_write(self, model, **hints):

        return 'writer'



class RouterTestCase(TestCase):

    multi_db = True
@@ -724,6 +729,37 @@ class RouterTestCase(TestCase): 
        self.assertTrue(router.allow_syncdb('other', User))

        self.assertFalse(router.allow_syncdb('other', Book))



    def test_partial_router(self):

        "A router can choose to implement a subset of methods"

        dive = Book.objects.using('other').create(title="Dive into Python",

                                                  published=datetime.date(2009, 5, 4))



        # First check the baseline behaviour



        self.assertEquals(router.db_for_read(User), 'other')

        self.assertEquals(router.db_for_read(Book), 'other')



        self.assertEquals(router.db_for_write(User), 'default')

        self.assertEquals(router.db_for_write(Book), 'default')



        self.assertTrue(router.allow_relation(dive, dive))



        self.assertTrue(router.allow_syncdb('default', User))

        self.assertTrue(router.allow_syncdb('default', Book))



        router.routers = [WriteRouter(), AuthRouter(), TestRouter()]



        self.assertEquals(router.db_for_read(User), 'other')

        self.assertEquals(router.db_for_read(Book), 'other')



        self.assertEquals(router.db_for_write(User), 'writer')

        self.assertEquals(router.db_for_write(Book), 'writer')



        self.assertTrue(router.allow_relation(dive, dive))



        self.assertFalse(router.allow_syncdb('default', User))

        self.assertTrue(router.allow_syncdb('default', Book))





    def test_database_routing(self):

        marty = Person.objects.using('default').create(name="Marty Alchin")