================================ Django 1.2 alpha 1 release notes ================================ January 5, 2010 Welcome to Django 1.2 alpha 1! This is the first in a series of preview/development releases leading up to the eventual release of Django 1.2, currently scheduled to take place in March 2010. This release is primarily targeted at developers who are interested in trying out new features and testing the Django codebase to help identify and resolve bugs prior to the final 1.2 release. As such, this release is *not* intended for production use, and any such use is discouraged. Backwards-incompatible changes in 1.2 ===================================== CSRF Protection --------------- There have been large changes to the way that CSRF protection works, detailed in :doc:`the CSRF documentation `. 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 UPGRADE INSTRUCTIONS to fix those templates. .. admonition:: Documentation removed The upgrade notes have been removed in current Django docs. Please refer to the docs for Django 1.3 or older to find these instructions. * ``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. * CSRF-related code 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__()) ``__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 of out ``__dict__``. ``get_db_prep_*()`` methods on Field ------------------------------------ Prior to v1.2, 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, and 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. Conversion functions has been provided which will transparently convert functions adhering to the old prototype into functions compatible with the new prototype. However, this conversion function will be removed in Django 1.4, so you should upgrade your Field definitions to use the new prototype. 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 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`. 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, since 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. 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 upgrading notes. .. admonition:: Documentation removed The upgrade notes have been removed in current Django docs. Please refer to the docs for Django 1.3 or older to find these instructions. ``SMTPConnection`` ------------------ The ``SMTPConnection`` class has been deprecated in favor of a generic Email 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 email 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 email, 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) 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.** Old-style database settings will be automatically translated to the new-style format. In the old-style (pre 1.2) format, there were a number of ``DATABASE_`` settings at the top level of your settings file. For example:: DATABASE_NAME = 'test_db' DATABASE_ENGINE = 'postgresql_psycopg2' DATABASE_USER = 'myusername' DATABASE_PASSWORD = 's3krit' These settings are now contained inside 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 to reflect the fact that they are stored in a dictionary. The sample settings given previously would now be stored using:: 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``). 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 :doc:`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 :doc:`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:: 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. What's new in Django 1.2 alpha 1 ================================ The following new features are present as of this alpha release; this release also marks the end of major feature development for the 1.2 release cycle. Some minor features will continue development until the 1.2 beta release, however. CSRF support ------------ Django now has much improved protection against :doc:`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. Email Backends -------------- You can now :ref:`configure the way that Django sends email `. Instead of using SMTP to send all email, you can now choose a configurable email 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 email backend that will allow Django's standard :doc:`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 email to a :ref:`file`, to the :ref:`console`, or to :ref:`memory` - you can even configure all email to be :ref:`thrown away`. Messages Framework ------------------ Django now includes a robust and configurable :doc:`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 :doc:`more than one database ` in your Django project. Queries can be issued at a specific database with the `using()` method on querysets; individual objects can be saved to a specific database by providing a ``using`` argument when you save the instance. '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
{{ 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 use the cached 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 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 ---------------------- The :djadmin:`test` subcommand of ``django-admin.py``, and the ``runtests.py`` script used to run Django's own test suite, support a new ``--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 run before the interruption. Improved localization --------------------- Django's :doc:`internationalization framework ` has been expanded by 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. Added ``readonly_fields`` to ``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 along side editable fields. Customizable syntax highlighting -------------------------------- You can now use the ``DJANGO_COLORS`` environment variable to modify or disable the colors used by ``django-admin.py`` to provide :ref:`syntax highlighting `. The Django 1.2 roadmap ====================== Before the final Django 1.2 release, several other preview/development releases will be made available. The current schedule consists of at least the following: * Week of **January 26, 2010**: First Django 1.2 beta release. Final feature freeze for Django 1.2. * Week of **March 2, 2010**: First Django 1.2 release candidate. String freeze for translations. * Week of **March 9, 2010**: Django 1.2 final release. If necessary, additional alpha, beta or release-candidate packages will be issued prior to the final 1.2 release. Django 1.2 will be released approximately one week after the final release candidate. What you can do to help ======================= In order to provide a high-quality 1.2 release, we need your help. Although this alpha release is, again, *not* intended for production use, you can help the Django team by trying out the alpha codebase in a safe test environment and reporting any bugs or issues you encounter. The Django ticket tracker is the central place to search for open issues: * https://code.djangoproject.com/timeline Please open new tickets if no existing ticket corresponds to a problem you're running into. Additionally, discussion of Django development, including progress toward the 1.2 release, takes place daily on the django-developers mailing list: * http://groups.google.com/group/django-developers ... and in the ``#django-dev`` IRC channel on ``irc.freenode.net``. If you're interested in helping out with Django's development, feel free to join the discussions there. Django's online documentation also includes pointers on how to contribute to Django: * :doc:`How to contribute to Django ` Contributions on any level -- developing code, writing documentation or simply triaging tickets and helping to test proposed bugfixes -- are always welcome and appreciated. Development sprints for Django 1.2 will also be taking place at PyCon US 2010, on the dedicated sprint days (February 22 through 25), and anyone who wants to help out is welcome to join in, either in person at PyCon or virtually in the IRC channel or on the mailing list.