Merged multi-auth branch to trunk. See the authentication docs for the ramifications of this change. Many, many thanks to Joseph Kocherhans for the hard work!

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3226 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/auth/backends.py

@@ -0,0 +1,21 @@
+from django.contrib.auth.models import User, check_password
+
+class ModelBackend:
+    """
+    Authenticate 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_user(self, user_id):
+        try:
+            return User.objects.get(pk=user_id)
+        except User.DoesNotExist:
+            return None