Django documentation

Porting your apps from Django 0.96 to 1.0

Django 1.0 breaks compatibility with 0.96 in some areas.

This guide will help you port 0.96 projects and apps to 1.0. The first part of this document includes the common changes needed to run with 1.0. If after going through the first part your code still breaks, check the section Less-common Changes for a list of a bunch of less-common compatibility issues.

See also

The 1.0 release notes. That document explains the new features in 1.0 more deeply; the porting guide is more concerned with helping you quickly update your code.

Common changes

This section describes the changes between 0.96 and 1.0 that most users will need to make.

Use Unicode

Change string literals ('foo') into Unicode literals (u'foo'). Django now uses Unicode strings throughout. In most places, raw strings will continue to work, but updating to use Unicode literals will prevent some obscure problems.

See Unicode data for full details.

Models

Common changes to your models file:

Rename maxlength to max_length

Rename your maxlength argument to max_length (this was changed to be consistent with form fields):

Replace __str__ with __unicode__

Replace your model’s __str__ function with a __unicode__ method, and make sure you use Unicode (u'foo') in that method.

Remove prepopulated_from

Remove the prepopulated_from argument on model fields. It’s no longer valid and has been moved to the ModelAdmin class in admin.py. See the admin, below, for more details about changes to the admin.

Remove core

Remove the core argument from your model fields. It is no longer necessary, since the equivalent functionality (part of inline editing) is handled differently by the admin interface now. You don’t have to worry about inline editing until you get to the admin section, below. For now, remove all references to core.

Replace class Admin: with admin.py

Remove all your inner class Admin declarations from your models. They won’t break anything if you leave them, but they also won’t do anything. To register apps with the admin you’ll move those declarations to an admin.py file; see the admin below for more details.

See also

A contributor to djangosnippets has written a script that’ll scan your models.py and generate a corresponding admin.py.

Example

Below is an example models.py file with all the changes you’ll need to make:

Old (0.96) models.py:

class Author(models.Model):
    first_name = models.CharField(maxlength=30)
    last_name = models.CharField(maxlength=30)
    slug = models.CharField(maxlength=60, prepopulate_from=('first_name', 'last_name'))

    class Admin:
        list_display = ['first_name', 'last_name']

    def __str__(self):
        return '%s %s' % (self.first_name, self.last_name)

New (1.0) models.py:

class Author(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)
    slug = models.CharField(max_length=60)

    def __unicode__(self):
        return u'%s %s' % (self.first_name, self.last_name)

New (1.0) admin.py:

from django.contrib import admin
from models import Author

class AuthorAdmin(admin.ModelAdmin):
    list_display = ['first_name', 'last_name']
    prepopulated_fields = {
        'slug': ('first_name', 'last_name')
    }

admin.site.register(Author, AuthorAdmin)

The Admin

One of the biggest changes in 1.0 is the new admin. The Django administrative interface (django.contrib.admin) has been completely refactored; admin definitions are now completely decoupled from model definitions, the framework has been rewritten to use Django’s new form-handling library and redesigned with extensibility and customization in mind.

Practically, this means you’ll need to rewrite all of your class Admin declarations. You’ve already seen in models above how to replace your class Admin with a admin.site.register() call in an admin.py file. Below are some more details on how to rewrite that Admin declaration into the new syntax.

Use new inline syntax

The new edit_inline options have all been moved to admin.py. Here’s an example:

Old (0.96):

class Parent(models.Model):
    ...

class Child(models.Model):
    parent = models.ForeignKey(Parent, edit_inline=models.STACKED, num_in_admin=3)

New (1.0):

class ChildInline(admin.StackedInline):
    model = Child
    extra = 3

class ParentAdmin(admin.ModelAdmin):
    model = Parent
    inlines = [ChildInline]

admin.site.register(Parent, ParentAdmin)

See InlineModelAdmin objects for more details.

Simplify fields, or use fieldsets

The old fields syntax was quite confusing, and has been simplified. The old syntax still works, but you’ll need to use fieldsets instead.

Old (0.96):

class ModelOne(models.Model):
    ...

    class Admin:
        fields = (
            (None, {'fields': ('foo','bar')}),
        )

class ModelTwo(models.Model):
    ...

    class Admin:
        fields = (
            ('group1', {'fields': ('foo','bar'),   'classes': 'collapse'}),
            ('group2', {'fields': ('spam','eggs'), 'classes': 'collapse wide'}),
        )

New (1.0):

class ModelOneAdmin(admin.ModelAdmin):
    fields = ('foo', 'bar')

class ModelTwoAdmin(admin.ModelAdmin):
    fieldsets = (
        ('group1', {'fields': ('foo','bar'),   'classes': 'collapse'}),
        ('group2', {'fields': ('spam','eggs'), 'classes': 'collapse wide'}),
    )

See also

URLs

Update your root urls.py

If you’re using the admin site, you need to update your root urls.py.

Old (0.96) urls.py:

from django.conf.urls.defaults import *

urlpatterns = patterns('',
    (r'^admin/', include('django.contrib.admin.urls')),

    # ... the rest of your URLs here ...
)

New (1.0) urls.py:

from django.conf.urls.defaults import *

# The next two lines enable the admin and load each admin.py file:
from django.contrib import admin
admin.autodiscover()

urlpatterns = patterns('',
    (r'^admin/(.*)', admin.site.root),

    # ... the rest of your URLs here ...
)

Views

Use django.forms instead of newforms

Replace django.newforms with django.forms – Django 1.0 renamed the newforms module (introduced in 0.96) to plain old forms. The oldforms module was also removed.

If you’re already using the newforms library, and you used our recommended import statement syntax, all you have to do is change your import statements.

Old:

from django import newforms as forms

New:

from django import forms

If you’re using the old forms system (formerly known as django.forms and django.oldforms), you’ll have to rewrite your forms. A good place to start is the forms documentation

Handle uploaded files using the new API

Replace use of uploaded files – that is, entries in request.FILES – as simple dictionaries with the new UploadedFile. The old dictionary syntax no longer works.

Thus, in a view like:

def my_view(request):
    f = request.FILES['file_field_name']
    ...

...you’d need to make the following changes:

Old (0.96) New (1.0)
f['content'] f.read()
f['filename'] f.name
f['content-type'] f.content_type

Work with file fields using the new API

The internal implementation of django.db.models.FileField have changed. A visible result of this is that the way you access special attributes (URL, filename, image size, etc) of these model fields has changed. You will need to make the following changes, assuming your model’s FileField is called myfile:

Old (0.96) New (1.0)
myfile.get_content_filename() myfile.content.path
myfile.get_content_url() myfile.content.url
myfile.get_content_size() myfile.content.size
myfile.save_content_file() myfile.content.save()
myfile.get_content_width() myfile.content.width
myfile.get_content_height() myfile.content.height

Note that the width and height attributes only make sense for ImageField fields. More details can be found in the model API documentation.

Use Paginator instead of ObjectPaginator

The ObjectPaginator in 0.96 has been removed and replaced with an improved version, django.core.paginator.Paginator.

Templates

Learn to love autoescaping

By default, the template system now automatically HTML-escapes the output of every variable. To learn more, see Automatic HTML escaping.

To disable auto-escaping for an individual variable, use the safe filter:

This will be escaped: {{ data }}
This will not be escaped: {{ data|safe }}

To disable auto-escaping for an entire template, wrap the template (or just a particular section of the template) in the autoescape tag:

{% autoescape off %}
   ... unescaped template content here ...
{% endautoescape %}

Less-common changes

The following changes are smaller, more localized changes. They should only affect more advanced users, but it’s probably worth reading through the list and checking your code for these things.

Signals

  • Add **kwargs to any registered signal handlers.
  • Connect, disconnect, and send signals via methods on the Signal object instead of through module methods in django.dispatch.dispatcher.
  • Remove any use of the Anonymous and Any sender options; they no longer exist. You can still receive signals sent by any sender by using sender=None
  • Make any custom signals you’ve declared into instances of django.dispatch.Signal instead of anonymous objects.

Here’s quick summary of the code changes you’ll need to make:

Old (0.96) New (1.0)
def callback(sender) def callback(sender, **kwargs)
sig = object() sig = django.dispatch.Signal()
dispatcher.connect(callback, sig) sig.connect(callback)
dispatcher.send(sig, sender) sig.send(sender)
dispatcher.connect(callback, sig, sender=Any) sig.connect(callback, sender=None)

Comments

If you were using Django 0.96’s django.contrib.comments app, you’ll need to upgrade to the new comments app introduced in 1.0. See Upgrading from Django’s previous comment system for details.

Template tags

spaceless tag

The spaceless template tag now removes all spaces between HTML tags, instead of preserving a single space.

Local flavors

U.S. local flavor

django.contrib.localflavor.usa has been renamed to django.contrib.localflavor.us. This change was made to match the naming scheme of other local flavors. To migrate your code, all you need to do is change the imports.

Sessions

Getting a new session key

SessionBase.get_new_session_key() has been renamed to _get_new_session_key(). get_new_session_object() no longer exists.

Fixtures

Loading a row no longer calls save()

Previously, loading a row automatically ran the model’s save() method. This is no longer the case, so any fields (for example: timestamps) that were auto-populated by a save() now need explicit values in any fixture.

Settings

Better exceptions

The old EnvironmentError has split into an ImportError when Django fails to find the settings module and a RuntimeError when you try to reconfigure settings after having already used them

LOGIN_URL has moved

The LOGIN_URL constant moved from django.contrib.auth into the settings module. Instead of using from django.contrib.auth import LOGIN_URL refer to settings.LOGIN_URL.

APPEND_SLASH behavior has been updated

In 0.96, if a URL didn’t end in a slash or have a period in the final component of its path, and APPEND_SLASH was True, Django would redirect to the same URL, but with a slash appended to the end. Now, Django checks to see whether the pattern without the trailing slash would be matched by something in your URL patterns. If so, no redirection takes place, because it is assumed you deliberately wanted to catch that pattern.

For most people, this won’t require any changes. Some people, though, have URL patterns that look like this:

r'/some_prefix/(.*)$'

Previously, those patterns would have been redirected to have a trailing slash. If you always want a slash on such URLs, rewrite the pattern as:

r'/some_prefix/(.*/)$'

Smaller model changes

Different exception from get()

Managers now return a MultipleObjectsReturned exception instead of AssertionError:

Old (0.96):

try:
    Model.objects.get(...)
except AssertionError:
    handle_the_error()

New (1.0):

try:
    Model.objects.get(...)
except Model.MultipleObjectsReturned:
    handle_the_error()

LazyDate has been fired

The LazyDate helper class no longer exists.

Default field values and query arguments can both be callable objects, so instances of LazyDate can be replaced with a reference to datetime.datetime.now:

Old (0.96):

class Article(models.Model):
    title = models.CharField(maxlength=100)
    published = models.DateField(default=LazyDate())

New (1.0):

import datetime

class Article(models.Model):
    title = models.CharField(max_length=100)
    published = models.DateField(default=datetime.datetime.now)

DecimalField is new, and FloatField is now a proper float

Old (0.96):

class MyModel(models.Model):
    field_name = models.FloatField(max_digits=10, decimal_places=3)
    ...

New (1.0):

class MyModel(models.Model):
    field_name = models.DecimalField(max_digits=10, decimal_places=3)
    ...

If you forget to make this change, you will see errors about FloatField not taking a max_digits attribute in __init__, because the new FloatField takes no precision-related arguments.

If you’re using MySQL or PostgreSQL, no further changes are needed. The database column types for DecimalField are the same as for the old FloatField.

If you’re using SQLite, you need to force the database to view the appropriate columns as decimal types, rather than floats. To do this, you’ll need to reload your data. Do this after you have made the change to using DecimalField in your code and updated the Django code.

Warning

Back up your database first!

For SQLite, this means making a copy of the single file that stores the database (the name of that file is the DATABASE_NAME in your settings.py file).

To upgrade each application to use a DecimalField, you can do the following, replacing <app> in the code below with each app’s name:

$ ./manage.py dumpdata --format=xml <app> > data-dump.xml
$ ./manage.py reset <app>
$ ./manage.py loaddata data-dump.xml

Notes:

  1. It’s important that you remember to use XML format in the first step of this process. We are exploiting a feature of the XML data dumps that makes porting floats to decimals with SQLite possible.
  2. In the second step you will be asked to confirm that you are prepared to lose the data for the application(s) in question. Say yes; we’ll restore this data in the third step, of course.
  3. DecimalField is not used in any of the apps shipped with Django prior to this change being made, so you do not need to worry about performing this procedure for any of the standard Django models.

If something goes wrong in the above process, just copy your backed up database file over the original file and start again.

Internationalization

django.views.i18n.set_language() now requires a POST request

Previously, a GET request was used. The old behavior meant that state (the locale used to display the site) could be changed by a GET request, which is against the HTTP specification’s recommendations. Code calling this view must ensure that a POST request is now made, instead of a GET. This means you can no longer use a link to access the view, but must use a form submission of some kind (e.g. a button).

_() is no longer in builtins

_() (the callable object whose name is a single underscore) is no longer monkeypatched into builtins – that is, it’s no longer available magically in every module.

If you were previously relying on _() always being present, you should now explicitly import ugettext or ugettext_lazy, if appropriate, and alias it to _ yourself:

from django.utils.translation import ugettext as _

HTTP request/response objects

Dictionary access to HttpRequest

HttpRequest objects no longer directly support dictionary-style access; previously, both GET and POST data were directly available on the HttpRequest object (e.g., you could check for a piece of form data by using if 'some_form_key' in request or by reading request['some_form_key']. This is no longer supported; if you need access to the combined GET and POST data, use request.REQUEST instead.

It is strongly suggested, however, that you always explicitly look in the appropriate dictionary for the type of request you expect to receive (request.GET or request.POST); relying on the combined request.REQUEST dictionary can mask the origin of incoming data.

Accessing HTTPResponse headers

django.http.HttpResponse.headers has been renamed to _headers and HttpResponse now supports containment checking directly. So use if header in response: instead of if header in response.headers:.

Generic relations

Generic relations have been moved out of core

The generic relation classes – GenericForeignKey and GenericRelation – have moved into the django.contrib.contenttypes module.

Testing

django.test.Client.login() has changed

Old (0.96):

from django.test import Client
c = Client()
c.login('/path/to/login','myuser','mypassword')

New (1.0):

# ... same as above, but then:
c.login(username='myuser', password='mypassword')

Management commands

Running management commands from your code

django.core.management has been greatly refactored.

Calls to management services in your code now need to use call_command. For example, if you have some test code that calls flush and load_data:

from django.core import management
management.flush(verbosity=0, interactive=False)
management.load_data(['test_data'], verbosity=0)

...you’ll need to change this code to read:

from django.core import management
management.call_command('flush', verbosity=0, interactive=False)
management.call_command('loaddata', 'test_data', verbosity=0)

Subcommands must now precede options

django-admin.py and manage.py now require subcommands to precede options. So:

$ django-admin.py --settings=foo.bar runserver

...no longer works and should be changed to:

$ django-admin.py runserver --settings=foo.bar

Syndication

Feed.__init__ has changed

The __init__() method of the syndication framework’s Feed class now takes an HttpRequest object as its second parameter, instead of the feed’s URL. This allows the syndication framework to work without requiring the sites framework. This only affects code that subclasses Feed and overrides the __init__() method, and code that calls Feed.__init__() directly.

Data structures

SortedDictFromList is gone

django.newforms.forms.SortedDictFromList was removed. django.utils.datastructures.SortedDict can now be instantiated with a sequence of tuples.

To update your code:

  1. Use django.utils.datastructures.SortedDict wherever you were using django.newforms.forms.SortedDictFromList.
  2. Because django.utils.datastructures.SortedDict.copy() doesn’t return a deepcopy as SortedDictFromList.copy() did, you will need to update your code if you were relying on a deepcopy. Do this by using copy.deepcopy directly.

Database backend functions

Database backend functions have been renamed

Almost all of the database backend-level functions have been renamed and/or relocated. None of these were documented, but you’ll need to change your code if you’re using any of these functions, all of which are in django.db:

Old (0.96) New (1.0)
backend.get_autoinc_sql connection.ops.autoinc_sql
backend.get_date_extract_sql connection.ops.date_extract_sql
backend.get_date_trunc_sql connection.ops.date_trunc_sql
backend.get_datetime_cast_sql connection.ops.datetime_cast_sql
backend.get_deferrable_sql connection.ops.deferrable_sql
backend.get_drop_foreignkey_sql connection.ops.drop_foreignkey_sql
backend.get_fulltext_search_sql connection.ops.fulltext_search_sql
backend.get_last_insert_id connection.ops.last_insert_id
backend.get_limit_offset_sql connection.ops.limit_offset_sql
backend.get_max_name_length connection.ops.max_name_length
backend.get_pk_default_value connection.ops.pk_default_value
backend.get_random_function_sql connection.ops.random_function_sql
backend.get_sql_flush connection.ops.sql_flush
backend.get_sql_sequence_reset connection.ops.sequence_reset_sql
backend.get_start_transaction_sql connection.ops.start_transaction_sql
backend.get_tablespace_sql connection.ops.tablespace_sql
backend.quote_name connection.ops.quote_name
backend.get_query_set_class connection.ops.query_set_class
backend.get_field_cast_sql connection.ops.field_cast_sql
backend.get_drop_sequence connection.ops.drop_sequence_sql
backend.OPERATOR_MAPPING connection.operators
backend.allows_group_by_ordinal connection.features.allows_group_by_ordinal
backend.allows_unique_and_pk connection.features.allows_unique_and_pk
backend.autoindexes_primary_keys connection.features.autoindexes_primary_keys
backend.needs_datetime_string_cast connection.features.needs_datetime_string_cast
backend.needs_upper_for_iops connection.features.needs_upper_for_iops
backend.supports_constraints connection.features.supports_constraints
backend.supports_tablespaces connection.features.supports_tablespaces
backend.uses_case_insensitive_names connection.features.uses_case_insensitive_names
backend.uses_custom_queryset connection.features.uses_custom_queryset

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