+
−try:
+
−    set
+
−except NameError:
+
−    from sets import Set as set # Python 2.3 fallback
+
−
+
−from django.db import connection
+
−from django.contrib.auth.models import User
+
−
+
−
+
−class ModelBackend(object):
+
−    """
+
−    Authenticates against django.contrib.auth.models.User.
+
−    """
+
−    # TODO: Model, login attribute name and password attribute name should be
+
−    # configurable.
+
−    def authenticate(self, username=None, password=None):
+
−        try:
+
−            user = User.objects.get(username=username)
+
−            if user.check_password(password):
+
−                return user
+
−        except User.DoesNotExist:
+
−            return None
+
−
+
−    def get_group_permissions(self, user_obj):
+
−        """
+
−        Returns a set of permission strings that this user has through his/her
+
−        groups.
+
−        """
+
−        if not hasattr(user_obj, '_group_perm_cache'):
+
−            cursor = connection.cursor()
+
−            # The SQL below works out to the following, after DB quoting:
+
−            # cursor.execute("""
+
−            #     SELECT ct."app_label", p."codename"
+
−            #     FROM "auth_permission" p, "auth_group_permissions" gp, "auth_user_groups" ug, "django_content_type" ct
+
−            #     WHERE p."id" = gp."permission_id"
+
−            #         AND gp."group_id" = ug."group_id"
+
−            #         AND ct."id" = p."content_type_id"
+
−            #         AND ug."user_id" = %s, [self.id])
+
−            qn = connection.ops.quote_name
+
−            sql = """
+
−                SELECT ct.%s, p.%s
+
−                FROM %s p, %s gp, %s ug, %s ct
+
−                WHERE p.%s = gp.%s
+
−                    AND gp.%s = ug.%s
+
−                    AND ct.%s = p.%s
+
−                    AND ug.%s = %%s""" % (
+
−                qn('app_label'), qn('codename'),
+
−                qn('auth_permission'), qn('auth_group_permissions'),
+
−                qn('auth_user_groups'), qn('django_content_type'),
+
−                qn('id'), qn('permission_id'),
+
−                qn('group_id'), qn('group_id'),
+
−                qn('id'), qn('content_type_id'),
+
−                qn('user_id'),)
+
−            cursor.execute(sql, [user_obj.id])
+
−            user_obj._group_perm_cache = set(["%s.%s" % (row[0], row[1]) for row in cursor.fetchall()])
+
−        return user_obj._group_perm_cache
+
−
+
−    def get_all_permissions(self, user_obj):
+
−        if not hasattr(user_obj, '_perm_cache'):
+
−            user_obj._perm_cache = set([u"%s.%s" % (p.content_type.app_label, p.codename) for p in user_obj.user_permissions.select_related()])
+
−            user_obj._perm_cache.update(self.get_group_permissions(user_obj))
+
−        return user_obj._perm_cache
+
−
+
−    def has_perm(self, user_obj, perm):
+
−        return perm in self.get_all_permissions(user_obj)
+
−
+
−    def has_module_perms(self, user_obj, app_label):
+
−        """
+
−        Returns True if user_obj has any permissions in the given app_label.
+
−        """
+
−        for perm in self.get_all_permissions(user_obj):
+
−            if perm[:perm.index('.')] == app_label:
+
−                return True
+
−        return False
+
−
+
−    def get_user(self, user_id):
+
−        try:
+
−            return User.objects.get(pk=user_id)
+
−        except User.DoesNotExist:
+
−            return None