============================================ Django 1.4 release notes - UNDER DEVELOPMENT ============================================ This page documents release notes for the as-yet-unreleased Django 1.4. As such, it's tentative and subject to change. It provides up-to-date information for those who are following trunk. Django 1.4 includes various `new features`_ and some minor `backwards incompatible changes`_. There are also some features that have been dropped, which are detailed in :doc:`our deprecation plan `, and we've `begun the deprecation process for some features`_. .. _new features: `What's new in Django 1.4`_ .. _backwards incompatible changes: backwards-incompatible-changes-1.4_ .. _begun the deprecation process for some features: deprecated-features-1.4_ Python compatibility ==================== While not a new feature, it's important to note that Django 1.4 introduces the second shift in our Python compatibility policy since Django's initial public debut. Django 1.2 dropped support for Python 2.3; now Django 1.4 drops support for Python 2.4. As such, the minimum Python version required for Django is now 2.5, and Django is tested and supported on Python 2.5, 2.6 and 2.7. This change should affect only a small number of Django users, as most operating-system vendors today are shipping Python 2.5 or newer as their default version. If you're still using Python 2.4, however, you'll need to stick to Django 1.3 until you can upgrade; per :doc:`our support policy `, Django 1.3 will continue to receive security support until the release of Django 1.5. Django does not support Python 3.x at this time. A document outlining our full timeline for deprecating Python 2.x and moving to Python 3.x will be published before the release of Django 1.4. What's new in Django 1.4 ======================== ``SELECT FOR UPDATE`` support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Django 1.4 now includes a :meth:`QuerySet.select_for_update() ` method which generates a ``SELECT ... FOR UPDATE`` SQL query. This will lock rows until the end of the transaction, meaning that other transactions cannot modify or delete rows matched by a ``FOR UPDATE`` query. For more details, see the documentation for :meth:`~django.db.models.query.QuerySet.select_for_update`. HTML5 ~~~~~ We've switched the admin and other bundled templates to use the HTML5 doctype. While Django will be careful in its use of HTML5 features, to maintain compatibility with old browsers, this change means that you can use any HTML5 features you need in admin pages without having to lose HTML validity or override the provided templates to change the doctype. List filters in admin interface ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Prior to Django 1.4, the Django admin app allowed specifying change list filters by specifying a field lookup (including spanning relations), and not custom filters. This has been rectified with a simple API previously known as "FilterSpec" which was used internally. For more details, see the documentation for :attr:`~django.contrib.admin.ModelAdmin.list_filter`. Multiple sort in admin interface ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The admin change list now supports sorting on multiple columns. It respects all elements of the :attr:`~django.contrib.admin.ModelAdmin.ordering` attribute, and sorting on multiple columns by clicking on headers is designed to work similarly to how desktop GUIs do it. The new hook :meth:`~django.contrib.admin.ModelAdmin.get_ordering` for specifying the ordering dynamically (e.g. depending on the request) has also been added. Tools for cryptographic signing ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Django 1.4 adds both a low-level API for signing values and a high-level API for setting and reading signed cookies, one of the most common uses of signing in Web applications. See :doc:`cryptographic signing ` docs for more information. New form wizard ~~~~~~~~~~~~~~~ The previously shipped ``FormWizard`` of the formtools contrib app has been replaced with a new implementation that is based on the class based views introduced in Django 1.3. It features a pluggable storage API and doesn't require the wizard to pass around hidden fields for every previous step. Django 1.4 ships with a session based storage backend and a cookie based storage backend. The latter uses the tools for :doc:`cryptographic signing ` also introduced in Django 1.4 to store the wizard state in the user's cookies. See the :doc:`form wizard ` docs for more information. Simple clickjacking protection ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We've added a middleware to provide easy protection against `clickjacking `_ using the X-Frame-Options header. It's not enabled by default for backwards compatibility reasons, but you'll almost certainly want to :doc:`enable it ` to help plug that security hole for browsers that support the header. ``reverse_lazy`` ~~~~~~~~~~~~~~~~ A lazily evaluated version of :func:`django.core.urlresolvers.reverse` was added to allow using URL reversals before the project's URLConf gets loaded. Assignment template tags ~~~~~~~~~~~~~~~~~~~~~~~~ A new helper function, :ref:`assignment_tag`, was added to ``template.Library`` to ease the creation of template tags that store some data in a specified context variable. CSRF improvements ~~~~~~~~~~~~~~~~~ We've made various improvements to our CSRF features, including the :func:`~django.views.decorators.csrf.ensure_csrf_cookie` decorator which can help with AJAX heavy sites, protection for PUT and DELETE, and settings :setting:`CSRF_COOKIE_SECURE` and :setting:`CSRF_COOKIE_PATH` which can improve the security and usefulness of the CSRF protection. See the :doc:`CSRF docs ` for more information. Error report filtering ~~~~~~~~~~~~~~~~~~~~~~ Two new function decorators, :func:`sensitive_variables` and :func:`sensitive_post_parameters`, were added to allow designating the traceback frames' local variables and request's POST parameters susceptible to contain sensitive information and that should be filtered out of error reports. All POST parameters are now systematically filtered out of error reports for certain :mod:`contrib.views.auth` views (``login``, ``password_reset_confirm``, ``password_change``, and ``add_view`` and ``user_change_password`` in the ``auth`` admin) to prevent the leaking of sensitive information such as user passwords. You may override or customize the default filtering by writing a :ref:`custom filter`. Learn more on :ref:`Filtering error reports`. Extended IPv6 support ~~~~~~~~~~~~~~~~~~~~~ The previously added support for IPv6 addresses when using the runserver management command in Django 1.3 has now been further extended by adding a :class:`~django.db.models.fields.GenericIPAddressField` model field, a :class:`~django.forms.fields.GenericIPAddressField` form field and the validators :data:`~django.core.validators.validate_ipv46_address` and :data:`~django.core.validators.validate_ipv6_address` Minor features ~~~~~~~~~~~~~~ Django 1.4 also includes several smaller improvements worth noting: * A more usable stacktrace in the technical 500 page: frames in the stack trace which reference Django's code are dimmed out, while frames in user code are slightly emphasized. This change makes it easier to scan a stacktrace for issues in user code. * Customizable names for :meth:`~django.template.Library.simple_tag`. .. _backwards-incompatible-changes-1.4: Backwards incompatible changes in 1.4 ===================================== Compatibility with old signed data ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Django 1.3 changed the cryptographic signing mechanisms used in a number of places in Django. While Django 1.3 kept fallbacks that would accept hashes produced by the previous methods, these fallbacks are removed in Django 1.4. So, if you upgrade to Django 1.4 directly from 1.2 or earlier, you may lose/invalidate certain pieces of data that have been cryptographically signed using an old method. To avoid this, use Django 1.3 first, for a period of time, to allow the signed data to expire naturally. The affected parts are detailed below, with 1) the consequences of ignoring this advice and 2) the amount of time you need to run Django 1.3 for the data to expire or become irrelevant. * contrib.sessions data integrity check * consequences: the user will be logged out, and session data will be lost. * time period: defined by SESSION_COOKIE_AGE. * contrib.auth password reset hash * consequences: password reset links from before the upgrade will not work. * time period: defined by PASSWORD_RESET_TIMEOUT_DAYS. Form related hashes — these are much shorter lifetime, and are relevant only for the short window where a user might fill in a form generated by the pre-upgrade Django instance, and try to submit it to the upgraded Django instance: * contrib.comments form security hash * consequences: the user will see a validation error "Security hash failed". * time period: the amount of time you expect users to take filling out comment forms. * FormWizard security hash * consequences: the user will see an error about the form having expired, and will be sent back to the first page of the wizard, losing the data they have inputted so far. * time period: the amount of time you expect users to take filling out the affected forms. * CSRF check * Note: This is actually a Django 1.1 fallback, not Django 1.2, and applies only if you are upgrading from 1.1. * consequences: the user will see a 403 error with any CSRF protected POST form. * time period: the amount of time you expect user to take filling out such forms. django.contrib.flatpages ~~~~~~~~~~~~~~~~~~~~~~~~ Starting in the 1.4 release the :class:`~django.contrib.flatpages.middleware.FlatpageFallbackMiddleware` only adds a trailing slash and redirects if the resulting URL refers to an existing flatpage. For example, requesting ``/notaflatpageoravalidurl`` in a previous version would redirect to ``/notaflatpageoravalidurl/``, which would subsequently raise a 404. Requesting ``/notaflatpageoravalidurl`` now will immediately raise a 404. Additionally redirects returned by flatpages are now permanent (301 status code) to match the behavior of the :class:`~django.middleware.common.CommonMiddleware`. `COMMENTS_BANNED_USERS_GROUP` setting ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Django's :doc:`comments app ` has historically supported excluding the comments of a special user group, but we've never documented the feature properly and didn't enforce the exclusion in other parts of the app, e.g., the template tags. To fix this problem, we removed the code from the feed class. If you rely on the feature and want to restore the old behavior, simply use a custom comment model manager to exclude the user group, like this:: from django.conf import settings from django.contrib.comments.managers import CommentManager class BanningCommentManager(CommentManager): def get_query_set(self): qs = super(BanningCommentManager, self).get_query_set() if getattr(settings, 'COMMENTS_BANNED_USERS_GROUP', None): where = ['user_id NOT IN (SELECT user_id FROM auth_user_groups WHERE group_id = %s)'] params = [settings.COMMENTS_BANNED_USERS_GROUP] qs = qs.extra(where=where, params=params) return qs Save this model manager in your custom comment app (e.g. in ``my_comments_app/managers.py``) and add it your :ref:`custom comment app model `:: from django.db import models from django.contrib.comments.models import Comment from my_comments_app.managers import BanningCommentManager class CommentWithTitle(Comment): title = models.CharField(max_length=300) objects = BanningCommentManager() For more details, see the documentation about :doc:`customizing the comments framework `. `IGNORABLE_404_STARTS` and `IGNORABLE_404_ENDS` settings ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Django can report 404 errors: see :doc:`/howto/error-reporting`. Until Django 1.3, it was possible to exclude some URLs from the reporting by adding prefixes to :setting:`IGNORABLE_404_STARTS` and suffixes to :setting:`IGNORABLE_404_ENDS`. In Django 1.4, these two settings are superseded by :setting:`IGNORABLE_404_URLS`, which is a list of compiled regular expressions. Django won't send an email for 404 errors on URLs that match any of them. Furthermore, the previous settings had some rather arbitrary default values:: IGNORABLE_404_STARTS = ('/cgi-bin/', '/_vti_bin', '/_vti_inf') IGNORABLE_404_ENDS = ('mail.pl', 'mailform.pl', 'mail.cgi', 'mailform.cgi', 'favicon.ico', '.php') It's not Django's role to decide if your website has a legacy ``/cgi-bin/`` section or a ``favicon.ico``. As a consequence, the default values of :setting:`IGNORABLE_404_URLS`, :setting:`IGNORABLE_404_STARTS` and :setting:`IGNORABLE_404_ENDS` are all now empty. If you have customized :setting:`IGNORABLE_404_STARTS` or :setting:`IGNORABLE_404_ENDS`, or if you want to keep the old default value, you should add the following lines in your settings file:: import re IGNORABLE_404_URLS = ( # for each in IGNORABLE_404_STARTS re.compile(r'^'), # for each in IGNORABLE_404_ENDS re.compile(r'$'), ) Don't forget to escape characters that have a special meaning in a regular expression. CSRF protection extended to PUT and DELETE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Previously, Django's :doc:`CSRF protection ` provided protection against only POST requests. Since use of PUT and DELETE methods in AJAX applications is becoming more common, we now protect all methods not defined as safe by RFC 2616 i.e. we exempt GET, HEAD, OPTIONS and TRACE, and enforce protection on everything. If you using PUT or DELETE methods in AJAX applications, please see the :ref:`instructions about using AJAX and CSRF `. ``django.core.template_loaders`` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This was an alias to ``django.template.loader`` since 2005, it has been removed without emitting a warning due to the length of the deprecation. If your code still referenced this please use ``django.template.loader`` instead. .. _deprecated-features-1.4: Features deprecated in 1.4 ========================== Old styles of calling ``cache_page`` decorator ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Some legacy ways of calling :func:`~django.views.decorators.cache.cache_page` have been deprecated, please see the docs for the correct way to use this decorator.