Django documentation

Django 1.3 alpha 1 release notes

November 11, 2010

Welcome to Django 1.3 alpha 1!

This is the first in a series of preview/development releases leading up to the eventual release of Django 1.3. 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 1.3 release.

As such, this release is not intended for production use, and any such use is discouraged.

As of this alpha release, Django 1.3 contains a number of nifty new features, lots of bug fixes, some minor backwards incompatible changes and an easy upgrade path from Django 1.2.

What’s new in Django 1.3 alpha 1

Class-based views

Django 1.3 adds a framework that allows you to use a class as a view. This means you can compose a view out of a collection of methods that can be subclassed and overridden to provide common views of data without having to write too much code.

Analogs of all the old function-based generic views have been provided, along with a completely generic view base class that can be used as the basis for reusable applications that can be easily extended.

See the documentation on Class-based Generic Views for more details. There is also a document to help you convert your function-based generic views to class-based views.

Logging

Django 1.3 adds framework-level support for Python’s logging module. This means you can now easily configure and control logging as part of your Django project. A number of logging handlers and logging calls have been added to Django’s own code as well – most notably, the error emails sent on a HTTP 500 server error are now handled as a logging activity. See the documentation on Django’s logging interface for more details.

Extended static files handling

Django 1.3 ships with a new contrib app 'django.contrib.staticfiles' to help developers handle the static media files (images, CSS, Javascript, etc.) that are needed to render a complete web page.

In previous versions of Django, it was common to place static assets in MEDIA_ROOT along with user-uploaded files, and serve them both at MEDIA_URL. Part of the purpose of introducing the staticfiles app is to make it easier to keep static files separate from user-uploaded files. Static assets should now go in static/ subdirectories of your apps or in other static assets directories listed in STATICFILES_DIRS, and will be served at STATIC_URL.

See the reference documentation of the app for more details or learn how to manage static files.

unittest2 support

Python 2.7 introduced some major changes to the unittest library, adding some extremely useful features. To ensure that every Django project can benefit from these new features, Django ships with a copy of unittest2, a copy of the Python 2.7 unittest library, backported for Python 2.4 compatibility.

To access this library, Django provides the django.utils.unittest module alias. If you are using Python 2.7, or you have installed unittest2 locally, Django will map the alias to the installed version of the unittest library. Otherwise, Django will use its own bundled version of unittest2.

To use this alias, simply use:

from django.utils import unittest

wherever you would have historically used:

import unittest

If you want to continue to use the base unittest library, you can – you just won’t get any of the nice new unittest2 features.

Transaction context managers

Users of Python 2.5 and above may now use transaction management functions as context managers. For example:

with transaction.autocommit():
    # ...

Configurable delete-cascade

ForeignKey and OneToOneField now accept an on_delete argument to customize behavior when the referenced object is deleted. Previously, deletes were always cascaded; available alternatives now include set null, set default, set to any value, protect, or do nothing.

For more information, see the on_delete documentation.

Contextual markers in translatable strings

For translation strings with ambiguous meaning, you can now use the pgettext function to specify the context of the string.

For more information, see Contextual markers

Everything else

Django 1.1 and 1.2 added lots of big ticket items to Django, like multiple-database support, model validation, and a session-based messages framework. However, this focus on big features came at the cost of lots of smaller features.

To compensate for this, the focus of the Django 1.3 development process has been on adding lots of smaller, long standing feature requests. These include:

  • Improved tools for accessing and manipulating the current Site via django.contrib.sites.models.get_current_site().
  • A RequestFactory for mocking requests in tests.
  • A new test assertion – assertNumQueries() – making it easier to test the database activity associated with a view.

Backwards-incompatible changes in 1.3 alpha 1

PasswordInput default rendering behavior

The PasswordInput form widget, intended for use with form fields which represent passwords, accepts a boolean keyword argument render_value indicating whether to send its data back to the browser when displaying a submitted form with errors. Prior to Django 1.3, this argument defaulted to True, meaning that the submitted password would be sent back to the browser as part of the form. Developers who wished to add a bit of additional security by excluding that value from the redisplayed form could instantiate a PasswordInput passing render_value=False .

Due to the sensitive nature of passwords, however, Django 1.3 takes this step automatically; the default value of render_value is now False, and developers who want the password value returned to the browser on a submission with errors (the previous behavior) must now explicitly indicate this. For example:

class LoginForm(forms.Form):
    username = forms.CharField(max_length=100)
    password = forms.CharField(widget=forms.PasswordInput(render_value=True))

Clearable default widget for FileField

Django 1.3 now includes a ClearableFileInput form widget in addition to FileInput. ClearableFileInput renders with a checkbox to clear the field’s value (if the field has a value and is not required); FileInput provided no means for clearing an existing file from a FileField.

ClearableFileInput is now the default widget for a FileField, so existing forms including FileField without assigning a custom widget will need to account for the possible extra checkbox in the rendered form output.

To return to the previous rendering (without the ability to clear the FileField), use the FileInput widget in place of ClearableFileInput. For instance, in a ModelForm for a hypothetical Document model with a FileField named document:

from django import forms
from myapp.models import Document

class DocumentForm(forms.ModelForm):
    class Meta:
        model = Document
        widgets = {'document': forms.FileInput}

New index on database session table

Prior to Django 1.3, the database table used by the database backend for the sessions app had no index on the expire_date column. As a result, date-based queries on the session table – such as the query that is needed to purge old sessions – would be very slow if there were lots of sessions.

If you have an existing project that is using the database session backend, you don’t have to do anything to accommodate this change. However, you may get a significant performance boost if you manually add the new index to the session table. The SQL that will add the index can be found by running the sqlindexes admin command:

python manage.py sqlindexes sessions

No more naughty words

Django has historically provided (and enforced) a list of profanities. The comments app has enforced this list of profanities, preventing people from submitting comments that contained one of those profanities.

Unfortunately, the technique used to implement this profanities list was woefully naive, and prone to the Scunthorpe problem. Fixing the built in filter to fix this problem would require significant effort, and since natural language processing isn’t the normal domain of a web framework, we have “fixed” the problem by making the list of prohibited words an empty list.

If you want to restore the old behavior, simply put a PROFANITIES_LIST setting in your settings file that includes the words that you want to prohibit (see the commit that implemented this change if you want to see the list of words that was historically prohibited). However, if avoiding profanities is important to you, you would be well advised to seek out a better, less naive approach to the problem.

Localflavor changes

Django 1.3 introduces the following backwards-incompatible changes to local flavors:

  • Indonesia (id) – The province “Nanggroe Aceh Darussalam (NAD)” has been removed from the province list in favor of the new official designation “Aceh (ACE)”.

Features deprecated in 1.3

Django 1.3 deprecates some features from earlier releases. These features are still supported, but will be gradually phased out over the next few release cycles.

Code taking advantage of any of the features below will raise a PendingDeprecationWarning in Django 1.3. This warning will be silent by default, but may be turned on using Python’s warnings module, or by running Python with a -Wd or -Wall flag.

In Django 1.4, these warnings will become a DeprecationWarning, which is not silent. In Django 1.5 support for these features will be removed entirely.

See also

For more details, see the documentation Django’s release process and our deprecation timeline.

mod_python support

The mod_python library has not had a release since 2007 or a commit since 2008. The Apache Foundation board voted to remove mod_python from the set of active projects in its version control repositories, and its lead developer has shifted all of his efforts toward the lighter, slimmer, more stable, and more flexible mod_wsgi backend.

If you are currently using the mod_python request handler, you are strongly encouraged to redeploy your Django instances using mod_wsgi.

Function-based generic views

As a result of the introduction of class-based generic views, the function-based generic views provided by Django have been deprecated. The following modules and the views they contain have been deprecated:

  • django.views.generic.create_update
  • django.views.generic.date_based
  • django.views.generic.list_detail
  • django.views.generic.simple

Test client response template attribute

Django’s test client returns Response objects annotated with extra testing information. In Django versions prior to 1.3, this included a template attribute containing information about templates rendered in generating the response: either None, a single Template object, or a list of Template objects. This inconsistency in return values (sometimes a list, sometimes not) made the attribute difficult to work with.

In Django 1.3 the template attribute is deprecated in favor of a new templates attribute, which is always a list, even if it has only a single element or no elements.

DjangoTestRunner

As a result of the introduction of support for unittest2, the features of django.test.simple.DjangoTestRunner (including fail-fast and Ctrl-C test termination) have been made redundant. In view of this redundancy, DjangoTestRunner has been turned into an empty placeholder class, and will be removed entirely in Django 1.5.

The Django 1.3 roadmap

Before the final Django 1.3 release, several other preview/development releases will be made available. The current schedule consists of at least the following:

  • Week of November 29, 2010: First Django 1.3 beta release. Final feature freeze for Django 1.3.
  • Week of January 10, 2011: First Django 1.3 release candidate. String freeze for translations.
  • Week of January 17, 2011: Django 1.3 final release.

If necessary, additional alpha, beta or release-candidate packages will be issued prior to the final 1.3 release. Django 1.3 will be released approximately one week after the final release candidate.

What you can do to help

In order to provide a high-quality 1.3 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:

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 1.3 release, takes place daily on the django-developers mailing list:

... 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:

Contributions on any level – developing code, writing documentation or simply triaging tickets and helping to test proposed bugfixes – are always welcome and appreciated.

Several development sprints will also be taking place before the 1.3 release; these will typically be announced in advance on the django-developers mailing list, and anyone who wants to help is welcome to join in.

Questions/Feedback

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