Fixed #11010 - Add a foundation for object permissions to authentication backends. Thanks to Florian Apolloner for writing the initial patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11807 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/auth/__init__.py

@@ -1,4 +1,5 @@
 import datetime
+from warnings import warn
 from django.core.exceptions import ImproperlyConfigured
 from django.utils.importlib import import_module
 
@@ -19,6 +20,12 @@ def load_backend(path):
         cls = getattr(mod, attr)
     except AttributeError:
         raise ImproperlyConfigured, 'Module "%s" does not define a "%s" authentication backend' % (module, attr)
+    try:
+        getattr(cls, 'supports_object_permissions')
+    except AttributeError:
+        warn("Authentication backends without a `supports_object_permissions` attribute are deprecated. Please define it in %s." % cls,
+             PendingDeprecationWarning)
+        cls.supports_object_permissions = False
     return cls()
 
 def get_backends():

django/contrib/auth/backends.py

@@ -11,6 +11,8 @@ class ModelBackend(object):
     """
     Authenticates against django.contrib.auth.models.User.
     """
+    supports_object_permissions = False
+
     # TODO: Model, login attribute name and password attribute name should be
     # configurable.
     def authenticate(self, username=None, password=None):

django/contrib/auth/models.py

@@ -121,7 +121,8 @@ class UserManager(models.Manager):
         return ''.join([choice(allowed_chars) for i in range(length)])
 
 class User(models.Model):
-    """Users within the Django authentication system are represented by this model.
+    """
+    Users within the Django authentication system are represented by this model.
 
     Username and password are required. Other fields are optional.
     """
@@ -151,11 +152,16 @@ class User(models.Model):
         return "/users/%s/" % urllib.quote(smart_str(self.username))
 
     def is_anonymous(self):
-        "Always returns False. This is a way of comparing User objects to anonymous users."
+        """
+        Always returns False. This is a way of comparing User objects to
+        anonymous users.
+        """
         return False
 
     def is_authenticated(self):
-        """Always return True. This is a way to tell if the user has been authenticated in templates.
+        """
+        Always return True. This is a way to tell if the user has been
+        authenticated in templates.
         """
         return True
 
@@ -194,30 +200,41 @@ class User(models.Model):
     def has_usable_password(self):
         return self.password != UNUSABLE_PASSWORD
 
-    def get_group_permissions(self):
+    def get_group_permissions(self, obj=None):
         """
         Returns a list of permission strings that this user has through
         his/her groups. This method queries all available auth backends.
+        If an object is passed in, only permissions matching this object
+        are returned.
         """
         permissions = set()
         for backend in auth.get_backends():
             if hasattr(backend, "get_group_permissions"):
-                permissions.update(backend.get_group_permissions(self))
+                if obj is not None and backend.supports_object_permissions:
+                    group_permissions = backend.get_group_permissions(self, obj)
+                else:
+                    group_permissions = backend.get_group_permissions(self)
+                permissions.update(group_permissions)
         return permissions
 
-    def get_all_permissions(self):
+    def get_all_permissions(self, obj=None):
         permissions = set()
         for backend in auth.get_backends():
             if hasattr(backend, "get_all_permissions"):
-                permissions.update(backend.get_all_permissions(self))
+                if obj is not None and backend.supports_object_permissions:
+                    all_permissions = backend.get_all_permissions(self, obj)
+                else:
+                    all_permissions = backend.get_all_permissions(self)
+                permissions.update(all_permissions)
         return permissions
 
-    def has_perm(self, perm):
+    def has_perm(self, perm, obj=None):
         """
         Returns True if the user has the specified permission. This method
         queries all available auth backends, but returns immediately if any
         backend returns True. Thus, a user who has permission from a single
-        auth backend is assumed to have permission in general.
+        auth backend is assumed to have permission in general. If an object
+        is provided, permissions for this specific object are checked.
         """
         # Inactive users have no permissions.
         if not self.is_active:
@@ -230,14 +247,22 @@ class User(models.Model):
         # Otherwise we need to check the backends.
         for backend in auth.get_backends():
             if hasattr(backend, "has_perm"):
-                if backend.has_perm(self, perm):
+                if obj is not None and backend.supports_object_permissions:
-                    return True
+                    if backend.has_perm(self, perm, obj):
+                        return True
+                else:
+                    if backend.has_perm(self, perm):
+                        return True
         return False
 
-    def has_perms(self, perm_list):
+    def has_perms(self, perm_list, obj=None):
-        """Returns True if the user has each of the specified permissions."""
+        """
+        Returns True if the user has each of the specified permissions.
+        If object is passed, it checks if the user has all required perms
+        for this object.
+        """
         for perm in perm_list:
-            if not self.has_perm(perm):
+            if not self.has_perm(perm, obj):
                 return False
         return True
 
@@ -358,10 +383,10 @@ class AnonymousUser(object):
         return self._user_permissions
     user_permissions = property(_get_user_permissions)
 
-    def has_perm(self, perm):
+    def has_perm(self, perm, obj=None):
         return False
 
-    def has_perms(self, perm_list):
+    def has_perms(self, perm_list, obj=None):
         return False
 
     def has_module_perms(self, module):

django/contrib/auth/tests/__init__.py

@@ -4,6 +4,7 @@ from django.contrib.auth.tests.views \
 from django.contrib.auth.tests.forms import FORM_TESTS
 from django.contrib.auth.tests.remote_user \
         import RemoteUserTest, RemoteUserNoCreateTest, RemoteUserCustomTest
+from django.contrib.auth.tests.auth_backends import BackendTest, RowlevelBackendTest
 from django.contrib.auth.tests.tokens import TOKEN_GENERATOR_TESTS
 
 # The password for the fixture data users is 'password'

django/contrib/auth/tests/auth_backends.py

@@ -0,0 +1,149 @@
+from django.conf import settings
+from django.contrib.auth.models import User, Group, Permission, AnonymousUser
+from django.contrib.contenttypes.models import ContentType
+from django.test import TestCase
+
+
+class BackendTest(TestCase):
+
+    backend = 'django.contrib.auth.backends.ModelBackend'
+
+    def setUp(self):
+        self.curr_auth = settings.AUTHENTICATION_BACKENDS
+        settings.AUTHENTICATION_BACKENDS = (self.backend,)
+        User.objects.create_user('test', 'test@example.com', 'test')
+
+    def tearDown(self):
+        settings.AUTHENTICATION_BACKENDS = self.curr_auth
+
+    def test_has_perm(self):
+        user = User.objects.get(username='test')
+        self.assertEqual(user.has_perm('auth.test'), False)
+        user.is_staff = True
+        user.save()
+        self.assertEqual(user.has_perm('auth.test'), False)
+        user.is_superuser = True
+        user.save()
+        self.assertEqual(user.has_perm('auth.test'), True)
+        user.is_staff = False
+        user.is_superuser = False
+        user.save()
+        self.assertEqual(user.has_perm('auth.test'), False)
+
+    def test_custom_perms(self):
+        user = User.objects.get(username='test')
+        content_type=ContentType.objects.get_for_model(Group)
+        perm = Permission.objects.create(name='test', content_type=content_type, codename='test')
+        user.user_permissions.add(perm)
+        user.save()
+
+        # reloading user to purge the _perm_cache
+        user = User.objects.get(username='test')
+        self.assertEqual(user.get_all_permissions() == set([u'auth.test']), True)
+        self.assertEqual(user.get_group_permissions(), set([]))
+        self.assertEqual(user.has_module_perms('Group'), False)
+        self.assertEqual(user.has_module_perms('auth'), True)
+        perm = Permission.objects.create(name='test2', content_type=content_type, codename='test2')
+        user.user_permissions.add(perm)
+        user.save()
+        perm = Permission.objects.create(name='test3', content_type=content_type, codename='test3')
+        user.user_permissions.add(perm)
+        user.save()
+        user = User.objects.get(username='test')
+        self.assertEqual(user.get_all_permissions(), set([u'auth.test2', u'auth.test', u'auth.test3']))
+        self.assertEqual(user.has_perm('test'), False)
+        self.assertEqual(user.has_perm('auth.test'), True)
+        self.assertEqual(user.has_perms(['auth.test2', 'auth.test3']), True)
+        perm = Permission.objects.create(name='test_group', content_type=content_type, codename='test_group')
+        group = Group.objects.create(name='test_group')
+        group.permissions.add(perm)
+        group.save()
+        user.groups.add(group)
+        user = User.objects.get(username='test')
+        exp = set([u'auth.test2', u'auth.test', u'auth.test3', u'auth.test_group'])
+        self.assertEqual(user.get_all_permissions(), exp)
+        self.assertEqual(user.get_group_permissions(), set([u'auth.test_group']))
+        self.assertEqual(user.has_perms(['auth.test3', 'auth.test_group']), True)
+
+        user = AnonymousUser()
+        self.assertEqual(user.has_perm('test'), False)
+        self.assertEqual(user.has_perms(['auth.test2', 'auth.test3']), False)
+
+
+class TestObj(object):
+    pass
+
+
+class SimpleRowlevelBackend(object):
+    supports_object_permissions = True
+
+    def has_perm(self, user, perm, obj=None):
+        if not obj:
+            return # We only support row level perms
+
+        if isinstance(obj, TestObj):
+            if user.username == 'test2':
+                return True
+            elif isinstance(user, AnonymousUser) and perm == 'anon':
+                return True
+        return False
+
+    def get_all_permissions(self, user, obj=None):
+        if not obj:
+            return [] # We only support row level perms
+
+        if not isinstance(obj, TestObj):
+            return ['none']
+
+        if user.username == 'test2':
+            return ['simple', 'advanced']
+        else:
+            return ['simple']
+
+    def get_group_permissions(self, user, obj=None):
+        if not obj:
+            return # We only support row level perms
+
+        if not isinstance(obj, TestObj):
+            return ['none']
+
+        if 'test_group' in [group.name for group in user.groups.all()]:
+            return ['group_perm']
+        else:
+            return ['none']
+
+
+class RowlevelBackendTest(TestCase):
+
+    backend = 'django.contrib.auth.tests.auth_backends.SimpleRowlevelBackend'
+
+    def setUp(self):
+        self.curr_auth = settings.AUTHENTICATION_BACKENDS
+        settings.AUTHENTICATION_BACKENDS = self.curr_auth + (self.backend,)
+        self.user1 = User.objects.create_user('test', 'test@example.com', 'test')
+        self.user2 = User.objects.create_user('test2', 'test2@example.com', 'test')
+        self.user3 = AnonymousUser()
+        self.user4 = User.objects.create_user('test4', 'test4@example.com', 'test')
+
+    def tearDown(self):
+        settings.AUTHENTICATION_BACKENDS = self.curr_auth
+
+    def test_has_perm(self):
+        self.assertEqual(self.user1.has_perm('perm', TestObj()), False)
+        self.assertEqual(self.user2.has_perm('perm', TestObj()), True)
+        self.assertEqual(self.user2.has_perm('perm'), False)
+        self.assertEqual(self.user2.has_perms(['simple', 'advanced'], TestObj()), True)
+        self.assertEqual(self.user3.has_perm('perm', TestObj()), False)
+        self.assertEqual(self.user3.has_perm('anon', TestObj()), False)
+        self.assertEqual(self.user3.has_perms(['simple', 'advanced'], TestObj()), False)
+
+    def test_get_all_permissions(self):
+        self.assertEqual(self.user1.get_all_permissions(TestObj()), set(['simple']))
+        self.assertEqual(self.user2.get_all_permissions(TestObj()), set(['simple', 'advanced']))
+        self.assertEqual(self.user2.get_all_permissions(), set([]))
+
+    def test_get_group_permissions(self):
+        content_type=ContentType.objects.get_for_model(Group)
+        group = Group.objects.create(name='test_group')
+        self.user4.groups.add(group)
+        self.assertEqual(self.user4.get_group_permissions(TestObj()), set(['group_perm']))

docs/internals/deprecation.txt

@@ -13,6 +13,10 @@ their deprecation, as per the :ref:`Django deprecation policy
           hooking up admin URLs.  This has been deprecated since the 1.1
           release.
 
+        * Authentication backends need to define the boolean attribute
+          ``supports_object_permissions``. The old backend style is deprecated
+          since the 1.2 release.
+
     * 1.4
         * ``CsrfResponseMiddleware``.  This has been deprecated since the 1.2
           release, in favour of the template tag method for inserting the CSRF
@@ -36,6 +40,10 @@ their deprecation, as per the :ref:`Django deprecation policy
           :ref:`messages framework <ref-contrib-messages>` should be used 
           instead.
 
+        * Authentication backends need to support the ``obj`` parameter for
+          permission checking. The ``supports_object_permissions`` variable
+          is not checked any longer and can be removed.
+
     * 2.0
         * ``django.views.defaults.shortcut()``. This function has been moved
           to ``django.contrib.contenttypes.views.shortcut()`` as part of the

docs/topics/auth.txt

@@ -202,29 +202,49 @@ Methods
         :meth:`~django.contrib.auth.models.User.set_unusable_password()` has
         been called for this user.
 
-    .. method:: models.User.get_group_permissions()
+    .. method:: models.User.get_group_permissions(obj=None)
 
         Returns a list of permission strings that the user has, through his/her
         groups.
 
-    .. method:: models.User.get_all_permissions()
+        .. versionadded:: 1.2
+
+        If ``obj`` is passed in, only returns the group permissions for
+        this specific object.
+
+    .. method:: models.User.get_all_permissions(obj=None)
 
         Returns a list of permission strings that the user has, both through
         group and user permissions.
 
-    .. method:: models.User.has_perm(perm)
+        .. versionadded:: 1.2
+
+        If ``obj`` is passed in, only returns the permissions for this
+        specific object.
+
+    .. method:: models.User.has_perm(perm, obj=None)
 
         Returns ``True`` if the user has the specified permission, where perm is
         in the format ``"<app label>.<permission codename>"``.
         If the user is inactive, this method will always return ``False``.
 
-    .. method:: models.User.has_perms(perm_list)
+        .. versionadded:: 1.2
+
+        If ``obj`` is passed in, this method won't check for a permission for
+        the model, but for this specific object.
+
+    .. method:: models.User.has_perms(perm_list, obj=None)
 
         Returns ``True`` if the user has each of the specified permissions,
         where each perm is in the format 
         ``"<app label>.<permission codename>"``. If the user is inactive,
         this method will always return ``False``.
 
+        .. versionadded:: 1.2
+
+        If ``obj`` is passed in, this method won't check for permissions for
+        the model, but for the specific object.
+
     .. method:: models.User.has_module_perms(package_name)
 
         Returns ``True`` if the user has any permissions in the given package
@@ -1521,3 +1541,24 @@ A full authorization implementation can be found in
 the ``auth_permission`` table most of the time.
 
 .. _django/contrib/auth/backends.py: http://code.djangoproject.com/browser/django/trunk/django/contrib/auth/backends.py
+
+Handling object permissions
+---------------------------
+
+Django's permission framework has a foundation for object permissions, though
+there is no implementation for it in the core. That means that checking for
+object permissions will always return ``False`` or an empty list (depending on
+the check performed).
+
+To enable object permissions in your own
+:ref:`authentication backend <ref-authentication-backends>` you'll just have
+to allow passing an ``obj`` parameter to the permission methods and set the
+``supports_objects_permissions`` class attribute to ``True``.
+
+A nonexistent ``supports_objects_permissions`` will raise a hidden
+``PendingDeprecationWarning`` if used in Django 1.2. In Django 1.3, this
+warning will be upgraded to a ``DeprecationWarning``, which will be displayed
+loudly. Additionally ``supports_objects_permissions`` will be set to ``False``.
+Django 1.4 will assume that every backend supports object permissions and
+won't check for the existence of ``supports_objects_permissions``, which
+means not supporting ``obj`` as a parameter will raise a ``TypeError``.

tests/regressiontests/auth_backends/tests.py

@@ -1,78 +0,0 @@
-try:
-    set
-except NameError:
-    from sets import Set as set     # Python 2.3 fallback
-
-__test__ = {'API_TESTS': """
->>> from django.contrib.auth.models import User, Group, Permission, AnonymousUser
->>> from django.contrib.contenttypes.models import ContentType
-
-# No Permissions assigned yet, should return False except for superuser
-
->>> user = User.objects.create_user('test', 'test@example.com', 'test')
->>> user.has_perm("auth.test")
-False
->>> user.is_staff=True
->>> user.save()
->>> user.has_perm("auth.test")
-False
->>> user.is_superuser=True
->>> user.save()
->>> user.has_perm("auth.test")
-True
->>> user.is_staff = False
->>> user.is_superuser = False
->>> user.save()
->>> user.has_perm("auth.test")
-False
->>> content_type=ContentType.objects.get_for_model(Group)
->>> perm = Permission.objects.create(name="test", content_type=content_type, codename="test")
->>> user.user_permissions.add(perm)
->>> user.save()
-
-# reloading user to purge the _perm_cache
-
->>> user = User.objects.get(username="test")
->>> user.get_all_permissions() == set([u'auth.test'])
-True
->>> user.get_group_permissions() == set([])
-True
->>> user.has_module_perms("Group")
-False
->>> user.has_module_perms("auth")
-True
->>> perm = Permission.objects.create(name="test2", content_type=content_type, codename="test2")
->>> user.user_permissions.add(perm)
->>> user.save()
->>> perm = Permission.objects.create(name="test3", content_type=content_type, codename="test3")
->>> user.user_permissions.add(perm)
->>> user.save()
->>> user = User.objects.get(username="test")
->>> user.get_all_permissions() == set([u'auth.test2', u'auth.test', u'auth.test3'])
-True
->>> user.has_perm('test')
-False
->>> user.has_perm('auth.test')
-True
->>> user.has_perms(['auth.test2', 'auth.test3'])
-True
->>> perm = Permission.objects.create(name="test_group", content_type=content_type, codename="test_group")
->>> group = Group.objects.create(name='test_group')
->>> group.permissions.add(perm)
->>> group.save()
->>> user.groups.add(group)
->>> user = User.objects.get(username="test")
->>> exp = set([u'auth.test2', u'auth.test', u'auth.test3', u'auth.test_group'])
->>> user.get_all_permissions() == exp
-True
->>> user.get_group_permissions() == set([u'auth.test_group'])
-True
->>> user.has_perms(['auth.test3', 'auth.test_group'])
-True
-
->>> user = AnonymousUser()
->>> user.has_perm('test')
-False
->>> user.has_perms(['auth.test2', 'auth.test3'])
-False
-"""}