.. _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's 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 --------------- We've made large changes to the way CSRF protection works, detailed in :ref:`the CSRF documentaton `. Here are the major changes you should 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. If you have used custom templates for contrib views, you MUST READ THE :ref:`UPGRADE INSTRUCTIONS ` to fix those templates. * ``CsrfViewMiddleware`` is included in :setting:`MIDDLEWARE_CLASSES` by default. This turns on CSRF protection by default, so 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 such as ``{% if not %}`` or ``{% if and %}`` will throw a ``TemplateSyntaxError``. Also, ``in`` is a new keyword and so is not a valid variable name in this context. ``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 require support for Python < 2.6, add the following code to the class:: __members__ = property(lambda self: self.__dir__()) Specifying databases -------------------- Prior to Django 1.1, Django used a number of settings to control access to a single database. Django 1.2 introduces support for multiple databases, and as a result, the way you define database settings has changed. Any existing Django settings file will continue to work as expected until Django 1.4. Until then, old-style database settings will be automatically translated to the new-style format. In the old-style (pre 1.2) format, you had a number of ``DATABASE_`` settings in your settings file. For example:: DATABASE_NAME = 'test_db' DATABASE_ENGINE = 'postgresql_psycopg2' DATABASE_USER = 'myusername' DATABASE_PASSWORD = 's3krit' These settings are now in a dictionary named :setting:`DATABASES`. Each item in the dictionary corresponds to a single database connection, with the name ``'default'`` describing the default database connection. The setting names have also been shortened. The previous sample settings would now look like this:: DATABASES = { 'default': { 'NAME': 'test_db', 'ENGINE': 'django.db.backends.postgresql_psycopg2', 'USER': 'myusername', 'PASSWORD': 's3krit', } } This affects the following settings: ========================================= ========================== Old setting New Setting ========================================= ========================== :setting:`DATABASE_ENGINE` :setting:`ENGINE` :setting:`DATABASE_HOST` :setting:`HOST` :setting:`DATABASE_NAME` :setting:`NAME` :setting:`DATABASE_OPTIONS` :setting:`OPTIONS` :setting:`DATABASE_PASSWORD` :setting:`PASSWORD` :setting:`DATABASE_PORT` :setting:`PORT` :setting:`DATABASE_USER` :setting:`USER` :setting:`TEST_DATABASE_CHARSET` :setting:`TEST_CHARSET` :setting:`TEST_DATABASE_COLLATION` :setting:`TEST_COLLATION` :setting:`TEST_DATABASE_NAME` :setting:`TEST_NAME` ========================================= ========================== These changes are also required if you have manually created a database connection using ``DatabaseWrapper()`` from your database backend of choice. In addition to the change in structure, Django 1.2 removes the special handling for the built-in database backends. All database backends must now be specified by a fully qualified module name (i.e., ``django.db.backends.postgresql_psycopg2``, rather than just ``postgresql_psycopg2``). ``__dict__`` on model instances ------------------------------- Historically, the ``__dict__`` attribute of a model instance has only contained attributes corresponding to the fields on a model. In order to support multiple database configurations, Django 1.2 has added a ``_state`` attribute to object instances. This attribute will appear in ``__dict__`` for a model instance. If your code relies on iterating over __dict__ to obtain a list of fields, you must now filter the ``_state`` attribute out of ``__dict__``. ``get_db_prep_*()`` methods on ``Field`` ---------------------------------------- Prior to 1.2, a custom ``Field`` had the option of defining several functions to support conversion of Python values into database-compatible values. A custom field might look something like:: class CustomModelField(models.Field): # ... def get_db_prep_save(self, value): # ... def get_db_prep_value(self, value): # ... def get_db_prep_lookup(self, lookup_type, value): # ... In 1.2, these three methods have undergone a change in prototype, and two extra methods have been introduced:: class CustomModelField(models.Field): # ... def get_prep_value(self, value): # ... def get_prep_lookup(self, lookup_type, value): # ... def get_db_prep_save(self, value, connection): # ... def get_db_prep_value(self, value, connection, prepared=False): # ... def get_db_prep_lookup(self, lookup_type, value, connection, prepared=False): # ... These changes are required to support multiple databases -- ``get_db_prep_*`` can no longer make any assumptions regarding the database for which it is preparing. The ``connection`` argument now provides the preparation methods with the specific connection for which the value is being prepared. The two new methods exist to differentiate general data-preparation requirements from requirements that are database-specific. The ``prepared`` argument is used to indicate to the database-preparation methods whether generic value preparation has been performed. If an unprepared (i.e., ``prepared=False``) value is provided to the ``get_db_prep_*()`` calls, they should invoke the corresponding ``get_prep_*()`` calls to perform generic data preparation. We've provided conversion functions that will transparently convert functions adhering to the old prototype into functions compatible with the new prototype. However, these conversion functions will be removed in Django 1.4, so you should upgrade your ``Field`` definitions to use the new prototype now, just to get it over with. If your ``get_db_prep_*()`` methods made no use of the database connection, you should be able to upgrade by renaming ``get_db_prep_value()`` to ``get_prep_value()`` and ``get_db_prep_lookup()`` to ``get_prep_lookup()`. If you require database specific conversions, then you will need to provide an implementation ``get_db_prep_*`` that uses the ``connection`` argument to resolve database-specific values. 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`. 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 from your own code, you should ensure that the ``Node`` implementation for each tag is thread-safe. For more information, see :ref:`template tag thread safety considerations`. Test runner exit status code ---------------------------- The exit status code of the test runners (``tests/runtests.py`` and ``python manage.py test``) no longer represents the number of failed tests, because a failure of 256 or more tests resulted in a wrong exit status code. The exit status code for the test runner is now 0 for success (no failing tests) and 1 for any number of test failures. If needed, the number of test failures can be found at the end of the test runner's output. Cookie encoding --------------- To fix bugs with cookies in Internet Explorer, Safari, and possibly other browsers, our encoding of cookie values was changed so that the characters comma and semi-colon are treated as non-safe characters, and are therefore encoded as ``\054`` and ``\073`` respectively. This could produce backwards incompatibilities, especially if you are storing comma or semi-colon in cookies and have javascript code that parses and manipulates cookie values client-side. ``user_passes_test``, ``login_required`` and ``permission_required`` -------------------------------------------------------------------- ``django.contrib.auth.decorators`` provides the decorators ``login_required``, ``permission_required`` and ``user_passes_test``. Previously it was possible to use these decorators both on functions (where the first argument is 'request') and on methods (where the first argument is 'self', and the second argument is 'request'). However, we have found that the trick which enabled this is flawed. It only works in limited circumstances, and produces errors that are very difficult to debug when it does not work. For this reason, the 'auto adapt' behaviour has been removed, and if you are using these decorators on methods, you will need to manually apply :func:`django.utils.decorators.method_decorator` to convert the decorator to one that works with methods. You would change code from this:: class MyClass(object): @login_required def my_view(self, request): pass to this:: from django.utils.decorators import method_decorator class MyClass(object): @method_decorator(login_required) def my_view(self, request): pass or:: from django.utils.decorators import method_decorator login_required_m = method_decorator(login_required) class MyClass(object): @login_required_m def my_view(self, request): pass For those following trunk, this change also applies to other decorators introduced since 1.1, including ``csrf_protect``, ``cache_control`` and anything created using ``decorator_from_middleware``. ``ModelForm.is_valid()`` and ``ModelForm.errors`` ------------------------------------------------- Much of the validation work for ModelForms has been moved down to the model level. As a result, the first time you call ``ModelForm.is_valid()``, access ``ModelForm.errors`` or otherwise trigger form validation, your model will be cleaned in-place. This conversion used to happen when the model was saved. If you need an unmodified instance of your model, you should pass a copy to the ``ModelForm`` constructor. .. _deprecated-features-1.2: ``BooleanField`` on MySQL -------------------------- In previous versions of Django ``BoleanFields`` under MySQL would return their values as either ``1`` or ``0``, instead of ``True`` or ``False``. For most people this shouldn't have been a problem because ``bool`` is a subclass of ``int``, however in Django 1.2 MySQL correctly returns a real ``bool``. The only time this should ever be an issue is if you were expecting printing the ``repr`` of a ``BooleanField`` to print ``1`` or ``0``. Features deprecated in 1.2 ========================== ``postgresql`` database backend ------------------------------- The ``psycopg1`` library has not been updated since October 2005. As a result, the ``postgresql`` database backend, which depends on this library, has been deprecated. If you are currently using the ``postgresql`` backend, you should migrate to using the ``postgresql_psycopg2`` backend. To update your code, install the ``psycopg2`` library and change the ``DATABASE_ENGINE`` setting to read ``postgresql_psycopg2``. 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 `. ``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.EmailBackend') 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.EmailBackend', 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 `. To upgrade your code, you need to replace any instances of this:: 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 `. You should begin to update your code to use the new API immediately. Date format helper functions ---------------------------- ``django.utils.translation.get_date_formats()`` and ``django.utils.translation.get_partial_date_formats()`` have been deprecated in favor of the appropriate calls to ``django.utils.formats.get_format()``, which is locale-aware when :setting:`USE_L10N` is set to ``True``, and falls back to default settings if set to ``False``. To get the different date formats, instead of writing this:: from django.utils.translation import get_date_formats date_format, datetime_format, time_format = get_date_formats() ...use:: from django.utils import formats date_format = formats.get_format('DATE_FORMAT') datetime_format = formats.get_format('DATETIME_FORMAT') time_format = formats.get_format('TIME_FORMAT') Or, when directly formatting a date value:: from django.utils import formats value_formatted = formats.date_format(value, 'DATETIME_FORMAT') The same applies to the globals found in ``django.forms.fields``: * ``DEFAULT_DATE_INPUT_FORMATS`` * ``DEFAULT_TIME_INPUT_FORMATS`` * ``DEFAULT_DATETIME_INPUT_FORMATS`` Use ``django.utils.formats.get_format()`` to get the appropriate formats. email_re -------- An undocumented regex for validating email addresses has been moved from django.form.fields to django.core.validators. You will need to update your imports if you are using it. Function-based test runners --------------------------- Django 1.2 changes the test runner tools to use a class-based approach. Old style function-based test runners will still work, but should be updated to use the new :ref:`class-based runners `. .. _1.2-updating-feeds: ``Feed`` in ``django.contrib.syndication.feeds`` ------------------------------------------------ The :class:`django.contrib.syndication.feeds.Feed` class has been replaced by the :class:`django.contrib.syndication.views.Feed` class. The old ``feeds.Feed`` class is deprecated, and will be removed in Django 1.4. The new class has an almost identical API, but allows instances to be used as views. For example, consider the use of the old framework in the following :ref:`URLconf `:: from django.conf.urls.defaults import * from myproject.feeds import LatestEntries, LatestEntriesByCategory feeds = { 'latest': LatestEntries, 'categories': LatestEntriesByCategory, } urlpatterns = patterns('', # ... (r'^feeds/(?P.*)/$', 'django.contrib.syndication.views.feed', {'feed_dict': feeds}), # ... ) Using the new Feed class, these feeds can be deployed directly as views:: from django.conf.urls.defaults import * from myproject.feeds import LatestEntries, LatestEntriesByCategory urlpatterns = patterns('', # ... (r'^feeds/latest/$', LatestEntries()), (r'^feeds/categories/(?P\d+)/$', LatestEntriesByCategory()), # ... ) If you currently use the ``feed()`` view, the ``LatestEntries`` class would not need to be modified apart from subclassing the new :class:`~django.contrib.syndication.views.Feed` class. However, ``LatestEntriesByCategory`` uses the ``get_object()`` method with the ``bits`` argument to specify a specific category to show. In the new :class:`~django.contrib.syndication.views.Feed` class, ``get_object()`` method takes a ``request`` and arguments from the URL, so it would look like this:: from django.contrib.syndication.views import Feed from django.shortcuts import get_object_or_404 from myproject.models import Category class LatestEntriesByCategory(Feed): def get_object(self, request, category_id): return get_object_or_404(Category, id=category_id) # ... Additionally, the ``get_feed()`` method on ``Feed`` classes now take different arguments, which may impact you if you use the ``Feed`` classes directly. Instead of just taking an optional ``url`` argument, it now takes two arguments: the object returned by its own ``get_object()`` method, and the current ``request`` object. To take into account ``Feed`` classes not being initialized for each request, the ``__init__()`` method now takes no arguments by default. Previously it would have taken the ``slug`` from the URL and the ``request`` object. In accordance with `RSS best practices`_, RSS feeds will now include an ``atom:link`` element. You may need to update your tests to take this into account. For more information, see the full :ref:`syndication framework documentation `. .. _RSS best practices: http://www.rssboard.org/rss-profile Technical message IDs --------------------- Up to version 1.1 Django used :ref:`technical message IDs` to provide localizers the possibility to translate date and time formats. They were translatable :term:`translation strings ` that could be recognized because they were all upper case (for example ``DATETIME_FORMAT``, ``DATE_FORMAT``, ``TIME_FORMAT``). They have been deprecated in favor of the new :ref:`Format localization ` infrastructure that allows localizers to specify that information in a ``formats.py`` file in the corresponding ``django/conf/locale//`` directory. What's new in Django 1.2 ======================== CSRF support ------------ Django now has much improved protection against :ref:`Cross-Site Request Forgery (CSRF) attacks`. 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 `. 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` 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`, to the :ref:`console`, or to :ref:`memory`. You can even configure all e-mail to be :ref:`thrown away`. Messages framework ------------------ Django now includes a robust and configurable :ref:`messages framework ` 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). Support for multiple databases ------------------------------ Django 1.2 adds the ability to use :ref:`more than one database ` in your Django project. Queries can be issued at a specific database with the `using()` method on ``QuerySet`` objects. Individual objects can be saved to a specific database by providing a ``using`` argument when you call ``save()``. 'Smart' if tag -------------- The :ttag:`if` tag has been upgraded to be much more powerful. First, we've added support for comparison operators. No longer will you have to type: .. code-block:: html+django {% ifnotequal a b %} ... {% endifnotequal %} You can now do this: .. code-block:: html+django {% if a != b %} ... {% endif %} There's really no reason to use ``{% ifequal %}`` or ``{% ifnotequal %}`` anymore, unless you're the nostalgic type. 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
{{ message }}
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 ` to load templates once, then cache 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`. Natural keys in fixtures ------------------------ Fixtures can now refer to remote objects using :ref:`topics-serialization-natural-keys`. This lookup scheme is an alternative to the normal primary-key based object references in a fixture, improving readability and resolving problems referring to objects whose primary key value may not be predictable or known. ``BigIntegerField`` ------------------- Models can now use a 64-bit :class:`~django.db.models.BigIntegerField` type. Fast failure for tests ---------------------- Both the :djadmin:`test` subcommand of ``django-admin.py`` and the ``runtests.py`` script used to run Django's own test suite now support a ``--failfast`` option. When specified, this option causes the test runner to exit after encountering a failure instead of continuing with the test run. In addition, the handling of ``Ctrl-C`` during a test run has been improved to trigger a graceful exit from the test run that reports details of the tests that were run before the interruption. Improved localization --------------------- Django's :ref:`internationalization framework ` has been expanded with locale-aware formatting and form processing. That means, if enabled, dates and numbers on templates will be displayed using the format specified for the current locale. Django will also use localized formats when parsing data in forms. See :ref:`Format localization ` for more details. ``readonly_fields`` in ``ModelAdmin`` ------------------------------------- :attr:`django.contrib.admin.ModelAdmin.readonly_fields` has been added to enable non-editable fields in add/change pages for models and inlines. Field and calculated values can be displayed alongside editable fields. Customizable syntax highlighting -------------------------------- You can now use a ``DJANGO_COLORS`` environment variable to modify or disable the colors used by ``django-admin.py`` to provide :ref:`syntax highlighting `. Model validation ---------------- Model instances now have support for :ref:`validating their own data `, and both model and form fields now accept configurable lists of :ref:`validators ` specifying reusable, encapsulated validation behavior. Note, however, that validation must still be performed explicitly. Simply invoking a model instance's ``save()`` method will not perform any validation of the instance's data. Object-level permissions ------------------------ A foundation for specifying permissions at the per-object level has been added. Although there is no implementation of this in core, a custom authentication backend can provide this implementation and it will be used by :class:`django.contrib.auth.models.User`. See the :ref:`authentication docs ` for more information. Permissions for anonymous users ------------------------------- If you provide a custom auth backend with ``supports_anonymous_user`` set to ``True``, AnonymousUser will check the backend for permissions, just like User already did. This is useful for centralizing permission handling - apps can always delegate the question of whether something is allowed or not to the authorization/authentication backend. See the :ref:`authentication docs ` for more details. Syndication feeds as views -------------------------- :ref:`Syndication feeds ` can now be used directly as views in your :ref:`URLconf `. This means that you can maintain complete control over the URL structure of your feeds. Like any other view, feeds views are passed a ``request`` object, so you can do anything you would normally do with a view, like user based access control, or making a feed a named URL. Relaxed requirements for usernames ---------------------------------- The built-in :class:`~django.contrib.auth.models.User` model's :attr:`~django.contrib.auth.models.User.username` field now allows a wider range of characters, including ``@``, ``+``, ``.`` and ``-`` characters.