django1/docs/releases/1.2.txt

.. _releases-1.2:

============================================
Django 1.2 release notes — UNDER DEVELOPMENT
============================================

This page documents release notes for the as-yet-unreleased Django 1.2.  As such
it is tentative and subject to change.  It provides up-to-date information for
those who are following trunk.

Django 1.2 includes a number of nifty `new features`_, lots of bug
fixes, and an easy upgrade path from Django 1.1.

.. _new features: `What's new in Django 1.2`_

.. _backwards-incompatible-changes-1.2:

Backwards-incompatible changes in 1.2
=====================================

CSRF Protection
---------------

There have been large changes to the way that CSRF protection works, detailed in
:ref:`the CSRF documentaton <ref-contrib-csrf>`.  The following are the major
changes that developers must be aware of:

 * ``CsrfResponseMiddleware`` and ``CsrfMiddleware`` have been deprecated, and
   will be removed completely in Django 1.4, in favor of a template tag that
   should be inserted into forms.

 * All contrib apps use a ``csrf_protect`` decorator to protect the view.  This
   requires the use of the csrf_token template tag in the template, so if you
   have used custom templates for contrib views, you MUST READ THE :ref:`UPGRADE
   INSTRUCTIONS <ref-csrf-upgrading-notes>` to fix those templates.

 * ``CsrfViewMiddleware`` is included in :setting:`MIDDLEWARE_CLASSES` by
   default. This turns on CSRF protection by default, so that views that accept
   POST requests need to be written to work with the middleware.  Instructions
   on how to do this are found in the CSRF docs.

 * All of the CSRF has moved from contrib to core (with backwards compatible
   imports in the old locations, which are deprecated).

:ttag:`if` tag changes
----------------------

Due to new features in the :ttag:`if` template tag, it no longer accepts 'and',
'or' and 'not' as valid **variable** names.  Previously that worked in some
cases even though these strings were normally treated as keywords.  Now, the
keyword status is always enforced, and template code like ``{% if not %}`` or
``{% if and %}`` will throw a TemplateSyntaxError.

``LazyObject``
--------------

``LazyObject`` is an undocumented utility class used for lazily wrapping other
objects of unknown type.  In Django 1.1 and earlier, it handled introspection in
a non-standard way, depending on wrapped objects implementing a public method
``get_all_members()``. Since this could easily lead to name clashes, it has been
changed to use the standard method, involving ``__members__`` and ``__dir__()``.
If you used ``LazyObject`` in your own code, and implemented the
``get_all_members()`` method for wrapped objects, you need to make the following
changes:

 * If your class does not have special requirements for introspection (i.e. you
   have not implemented ``__getattr__()`` or other methods that allow for
   attributes not discoverable by normal mechanisms), you can simply remove the
   ``get_all_members()`` method.  The default implementation on ``LazyObject``
   will do the right thing.

 * If you have more complex requirements for introspection, first rename the
   ``get_all_members()`` method to ``__dir__()``.  This is the standard method,
   from Python 2.6 onwards, for supporting introspection.  If you are require
   support for Python < 2.6, add the following code to the class::

       __members__ = property(lambda self: self.__dir__())

Stateful template tags
----------------------

Template tags that store rendering state on the node itself may experience
problems if they are used with the new :ref:`cached
template loader<template-loaders>`.

All of the built-in Django template tags are safe to use with the cached
loader, but if you're using custom template tags that come from third
party packages, or that you wrote yourself, you should ensure that the
``Node`` implementation for each tag is thread-safe. For more
information, see
:ref:`template tag thread safety considerations<template_tag_thread_safety>`.

.. _deprecated-features-1.2:

Features deprecated in 1.2
==========================

CSRF response rewriting middleware
----------------------------------

``CsrfResponseMiddleware``, the middleware that automatically inserted CSRF
tokens into POST forms in outgoing pages, has been deprecated in favor of a
template tag method (see above), and will be removed completely in Django
1.4. ``CsrfMiddleware``, which includes the functionality of
``CsrfResponseMiddleware`` and ``CsrfViewMiddleware`` has likewise been
deprecated.

Also, the CSRF module has moved from contrib to core, and the old imports are
deprecated, as described in the :ref:`upgrading notes <ref-csrf-upgrading-notes>`.

``SMTPConnection``
------------------

The ``SMTPConnection`` class has been deprecated in favor of a generic
E-mail backend API. Old code that explicitly instantiated an instance
of an SMTPConnection::

    from django.core.mail import SMTPConnection
    connection = SMTPConnection()
    messages = get_notification_email()
    connection.send_messages(messages)

should now call :meth:`~django.core.mail.get_connection()` to
instantiate a generic e-mail connection::

    from django.core.mail import get_connection
    connection = get_connection()
    messages = get_notification_email()
    connection.send_messages(messages)

Depending on the value of the :setting:`EMAIL_BACKEND` setting, this
may not return an SMTP connection. If you explicitly require an SMTP
connection with which to send e-mail, you can explicitly request an
SMTP connection::

    from django.core.mail import get_connection
    connection = get_connection('django.core.mail.backends.smtp')
    messages = get_notification_email()
    connection.send_messages(messages)

If your call to construct an instance of ``SMTPConnection`` required
additional arguments, those arguments can be passed to the
:meth:`~django.core.mail.get_connection()` call::

    connection = get_connection('django.core.mail.backends.smtp', hostname='localhost', port=1234)

User Messages API
-----------------

The API for storing messages in the user ``Message`` model (via
``user.message_set.create``) is now deprecated and will be removed in Django
1.4 according to the standard :ref:`release process <internals-release-process>`.

To upgrade your code, you need to replace any instances of::

    user.message_set.create('a message')

with the following::

    from django.contrib import messages
    messages.add_message(request, messages.INFO, 'a message')

Additionally, if you make use of the method, you need to replace the
following::

    for message in user.get_and_delete_messages():
        ...

with::

    from django.contrib import messages
    for message in messages.get_messages(request):
        ...

For more information, see the full
:ref:`messages documentation <ref-contrib-messages>`. You should begin to
update your code to use the new API immediately.

What's new in Django 1.2
========================

CSRF support
------------

Django now has much improved protection against :ref:`Cross-Site
Request Forgery (CSRF) attacks<ref-contrib-csrf>`. This type of attack
occurs when a malicious Web site contains a link, a form button or
some javascript that is intended to perform some action on your Web
site, using the credentials of a logged-in user who visits the
malicious site in their browser. A related type of attack, 'login
CSRF', where an attacking site tricks a user's browser into logging
into a site with someone else's credentials, is also covered.

E-mail Backends
---------------

You can now :ref:`configure the way that Django sends e-mail
<topic-email-backends>`. Instead of using SMTP to send all e-mail, you
can now choose a configurable e-mail backend to send messages. If your
hosting provider uses a sandbox or some other non-SMTP technique for
sending mail, you can now construct an e-mail backend that will allow
Django's standard :ref:`mail sending methods<topics-email>` to use
those facilities.

This also makes it easier to debug mail sending - Django ships with
backend implementations that allow you to send e-mail to a
:ref:`file<topic-email-file-backend>`, to the
:ref:`console<topic-email-console-backend>`, or to
:ref:`memory<topic-email-memory-backend>` - you can even configure all
e-mail to be :ref:`thrown away<topic-email-dummy-backend>`.

Messages Framework
------------------

Django now includes a robust and configurable :ref:`messages framework
<ref-contrib-messages>` with built-in support for cookie- and session-based
messaging, for both anonymous and authenticated clients. The messages framework
replaces the deprecated user message API and allows you to temporarily store
messages in one request and retrieve them for display in a subsequent request
(usually the next one).

'Smart' if tag
--------------

The :ttag:`if` tag has been upgraded to be much more powerful.  First, support
for comparison operators has been added. No longer will you have to type:

.. code-block:: html+django

    {% ifnotequal a b %}
     ...
    {% endifnotequal %}

...as you can now do:

.. code-block:: html+django

    {% if a != b %}
     ...
    {% endif %}

The operators supported are ``==``, ``!=``, ``<``, ``>``, ``<=``, ``>=`` and
``in``, all of which work like the Python operators, in addition to ``and``,
``or`` and ``not`` which were already supported.

Also, filters may now be used in the ``if`` expression. For example:

.. code-block:: html+django

      <div
        {% if user.email|lower == message.recipient|lower %}
          class="highlight"
        {% endif %}
      >{{ message }}</div>

Template caching
----------------

In previous versions of Django, every time you rendered a template it
would be reloaded from disk. In Django 1.2, you can use a :ref:`cached
template loader <template-loaders>` to load templates once, then use a
cached the result for every subsequent render. This can lead to a
significant performance improvement if your templates are broken into
lots of smaller subtemplates (using the ``{% extends %}`` or ``{%
include %}`` tags).

As a side effect, it is now much easier to support non-Django template
languages. For more details, see the :ref:`notes on supporting
non-Django template languages<topic-template-alternate-language>`.