Django 3.0 release notes
Welcome to Django 3.0!
These release notes cover the , as well as some backwards incompatible changes you’ll want to be aware of when upgrading from Django 2.2 or earlier. We’ve that have reached the end of their deprecation cycle, and we’ve begun the deprecation process for some features.
如果你要更新现有的项目,请看 指南。
Django 3.0 supports Python 3.6, 3.7, 3.8, and 3.9 (as of 3.0.11). We highly recommend and only officially support the latest release of each series.
The Django 2.2.x series is the last to support Python 3.5.
Third-party library support for older version of Django
Following the release of Django 3.0, we suggest that third-party app authors drop support for all versions of Django prior to 2.2. At that time, you should be able to run your package’s tests using python -Wd
so that deprecation warnings appear. After making the deprecation warning fixes, your app should be compatible with Django 3.0.
Django now officially supports MariaDB 10.1 and higher. See for more details.
ASGI support
Django 3.0 begins our journey to making Django fully async-capable by providing support for running as an ASGI application.
This is in addition to our existing WSGI support. Django intends to support both for the foreseeable future. Async features will only be available to applications that run under ASGI, however.
At this stage async support only applies to the outer ASGI application. Internally everything remains synchronous. Asynchronous middleware, views, etc. are not yet supported. You can, however, use ASGI middleware around Django’s application, allowing you to combine Django with other ASGI frameworks.
There is no need to switch your applications over unless you want to start experimenting with asynchronous code, but we have if you want to learn more.
Note that as a side-effect of this change, Django is now aware of asynchronous event loops and will block you calling code marked as “async unsafe” - such as ORM operations - from an asynchronous context. If you were using Django from async code before, this may trigger if you were doing it incorrectly. If you see a SynchronousOnlyOperation
error, then closely examine your code and move any database operations to be in a synchronous child thread.
Exclusion constraints on PostgreSQL
The new ExclusionConstraint
class enable adding exclusion constraints on PostgreSQL. Constraints are added to models using the option.
Filter expressions
Expressions that output BooleanField
may now be used directly in QuerySet
filters, without having to first annotate and then filter against the annotation.
Enumerations for model field choices
次要特性
- Added support for the
admin_order_field
attribute on properties inModelAdmin.list_display
. - The new method allows specifying the inlines based on the request or model instance.
- Select2 library is upgraded from version 4.0.3 to 4.0.7.
- jQuery is upgraded from version 3.3.1 to 3.4.1.
django.contrib.auth
- The new
reset_url_token
attribute in allows specifying a token parameter displayed as a component of password reset URLs. - Added
BaseBackend
class to ease customization of authentication backends. - Added method to mirror the existing
get_group_permissions()
method. - Added HTML
autocomplete
attribute to widgets of username, email, and password fields in for better interaction with browser password managers. createsuperuser
now falls back to environment variables for password and required fields, when a corresponding command line argument isn’t provided in non-interactive mode.- The new method returns users that have the specified permission.
- The default iteration count for the PBKDF2 password hasher is increased from 150,000 to 180,000.
django.contrib.gis
- Allowed MySQL spatial lookup functions to operate on real geometries. Previous support was limited to bounding boxes.
- Added the function, supported on PostGIS.
- Added support for the
furlong
unit inDistance
. - The setting now supports
pathlib.Path
. - The class now accepts
pathlib.Path
path
.
- The new
RangeOperators
helps to avoid typos in SQL operators that can be used together with . - The new
RangeBoundary
expression represents the range boundaries. - The new and
RemoveIndexConcurrently
classes allow creating and dropping indexesCONCURRENTLY
on PostgreSQL.
- The new
get_session_cookie_age()
method allows dynamically specifying the session cookie age.
- Added the
language
class attribute to thedjango.contrib.syndication.views.Feed
to customize a feed language. The default value is instead ofLANGUAGE_CODE
.
缓存
- and
never_cache()
now add theprivate
directive toCache-Control
headers.
文件存储
- The new method allows customizing the algorithm for generating filenames if a file with the uploaded name already exists.
表单
- Formsets may control the widget used when ordering forms via
can_order
by setting the attribute or overridingget_ordering_widget()
.
国际化
- Added the ,
LANGUAGE_COOKIE_SAMESITE
, and settings to set theHttpOnly
,SameSite
, andSecure
flags on language cookies. The default values of these settings preserve the previous behavior. - Added support and translations for the Uzbek language.
日志
- The new
reporter_class
parameter ofAdminEmailHandler
allows providing andjango.views.debug.ExceptionReporter
subclass to customize the traceback text sent to site whenDEBUG
isFalse
.
管理命令
- The new option allows ignoring specific directories when searching for
.po
files to compile. showmigrations --list
now shows the applied datetimes when--verbosity
is 2 and above.- On PostgreSQL, now supports client-side TLS certificates.
inspectdb
now introspects when a foreign key has a unique or primary key constraint.- The new
--skip-checks
option skips running system checks prior to running the command. - The and
startproject --template
options now support templates stored in XZ archives (.tar.xz
,.txz
) and LZMA archives (.tar.lzma
,.tlz
).
模型
Added hash database functions ,
SHA1
, ,SHA256
, , andSHA512
.Added the database function.
The new parameter of the
Trunc
database functions determines the treatment of nonexistent and ambiguous datetimes.connection.queries
now showsCOPY … TO
statements on PostgreSQL.now accepts a callable for
path
.Allowed symmetrical intermediate table for self-referential
ManyToManyField
.The
name
attributes of ,UniqueConstraint
, and now support app label and class interpolation using the'%(app_label)s'
and'%(class)s'
placeholders.The new
Field.descriptor_class
attribute allows model fields to customize the get and set behavior by overriding their .Avg
and now support thedistinct
argument.Added
SmallAutoField
which acts much like an except that it only allows values under a certain (database-dependent) limit. Values from1
to32767
are safe in all databases supported by Django.AutoField
, , andSmallAutoField
now inherit fromIntegerField
,BigIntegerField
andSmallIntegerField
respectively. System checks and validators are now also properly inherited.now supports
pathlib.Path
.is now supported on MySQL 8.0.16+.
The new
allows_group_by_selected_pks_on_model()
method ofdjango.db.backends.base.BaseDatabaseFeatures
allows optimization ofGROUP BY
clauses to require only the selected models’ primary keys. By default, it’s supported only for managed models on PostgreSQL.
请求和响应
- Allowed
HttpResponse
to be initialized with content. - For use in, for example, Django templates,
HttpRequest.headers
now allows lookups using underscores (e.g.user_agent
) in place of hyphens.
安全
- now defaults to
'DENY'
. In older versions, theX_FRAME_OPTIONS
setting defaults to'SAMEORIGIN'
. If your site uses frames of itself, you will need to explicitly setX_FRAME_OPTIONS = 'SAMEORIGIN'
for them to continue working. - now defaults to
True
. With this enabled,SecurityMiddleware
sets the header on all responses that do not already have it. SecurityMiddleware
can now send the header.
测试
- The new test
Client
argumentraise_request_exception
allows controlling whether or not exceptions raised during the request should also be raised in the test. The value defaults toTrue
for backwards compatibility. If it isFalse
and an exception occurs, the test client will return a 500 response with the attribute , a tuple providing information of the exception that occurred. - Tests and test cases to run can be selected by test name pattern using the new
test -k
option. - HTML comparison, as used by , now treats text, character references, and entity references that refer to the same character as equivalent.
- Django test runner now supports headless mode for selenium tests on supported browsers. Add the
--headless
option to enable this mode. - Django test runner now supports
--start-at
and--start-after
options to run tests starting from a specific top-level module. - Django test runner now supports a
--pdb
option to spawn a debugger at each error or failure.
Backwards incompatible changes in 3.0
Model.save()
no longer attempts to find a row when saving a new Model
instance and a default value for the primary key is provided, and always performs a single INSERT
query. In older Django versions, Model.save()
performed either an INSERT
or an UPDATE
based on whether or not the row exists.
This makes calling Model.save()
while providing a default primary key value equivalent to passing to model’s save()
. Attempts to use a new Model
instance to update an existing row will result in an IntegrityError
.
In order to update an existing model for a specific primary key value, use the update_or_create()
method or QuerySet.filter(pk=…).update(…)
instead. For example:
数据库后端 API
本节介绍了第三方数据库后端可能需要的更改。
DatabaseIntrospection.get_field_type()
may no longer return tuples.- If the database can create foreign keys in the same SQL statement that adds a field, add
SchemaEditor.sql_create_column_inline_fk
with the appropriate SQL; otherwise, setDatabaseFeatures.can_create_inline_fk = False
. DatabaseFeatures.can_return_id_from_insert
andcan_return_ids_from_bulk_insert
are renamed tocan_return_columns_from_insert
andcan_return_rows_from_bulk_insert
.- Database functions now handle formats when created using
datetime.timedelta
instances (e.g.timezone(timedelta(hours=5))
, which would output'UTC+05:00'
). Third-party backends should handle this format when preparing indatetime_cast_date_sql()
,datetime_extract_sql()
, etc. - Entries for
AutoField
,BigAutoField
, andSmallAutoField
are added toDatabaseOperations.integer_field_ranges
to support the integer range validators on these field types. Third-party backends may need to customize the default entries. DatabaseOperations.fetch_returned_insert_id()
is replaced byfetch_returned_insert_columns()
which returns a list of values returned by theINSERT … RETURNING
statement, instead of a single value.DatabaseOperations.return_insert_id()
is replaced byreturn_insert_columns()
that accepts afields
argument, which is an iterable of fields to be returned after insert. Usually this is only the auto-generated primary key.
django.contrib.admin
- Admin’s model history change messages now prefers more readable field labels instead of field names.
- Support for PostGIS 2.1 is removed.
- Support for SpatiaLite 4.1 and 4.2 is removed.
- Support for GDAL 1.11 and GEOS 3.4 is removed.
Dropped support for PostgreSQL 9.4
Upstream support for PostgreSQL 9.4 ends in December 2019. Django 3.0 supports PostgreSQL 9.5 and higher.
Dropped support for Oracle 12.1
Upstream support for Oracle 12.1 ends in July 2021. Django 2.2 will be supported until April 2022. Django 3.0 officially supports Oracle 12.2 and 18c.
While Python 2 support was removed in Django 2.0, some private APIs weren’t removed from Django so that third party apps could continue using them until the Python 2 end-of-life.
Since we expect apps to drop Python 2 compatibility when adding support for Django 3.0, we’re removing these APIs at this time.
django.test.utils.str_prefix()
- Strings don’t have ‘u’ prefixes in Python 3.django.test.utils.patch_logger()
- Useunittest.TestCase.assertLogs()
instead.django.utils.lru_cache.lru_cache()
- Alias of .django.utils.decorators.available_attrs()
- This function returns .django.utils.decorators.ContextDecorator
- Alias ofcontextlib.ContextDecorator
.django.utils._os.abspathu()
- Alias of .django.utils._os.upath()
andnpath()
- These functions do nothing on Python 3.django.utils.six
- Remove usage of this vendored library or switch to six.django.utils.encoding.python_2_unicode_compatible()
- Alias ofsix.python_2_unicode_compatible()
.django.utils.functional.curry()
- Use orfunctools.partialmethod
. See .django.utils.safestring.SafeBytes
- Unused since Django 2.0.
New default value for the FILE_UPLOAD_PERMISSIONS
setting
In older versions, the FILE_UPLOAD_PERMISSIONS
setting defaults to None
. With the default , this results in uploaded files having different permissions depending on their size and which upload handler is used.
FILE_UPLOAD_PERMISSIONS
now defaults to 0o644
to avoid this inconsistency.
New default values for security settings
To make Django projects more secure by default, some security settings now have more secure default values:
X_FRAME_OPTIONS
now defaults to'DENY'
.- now defaults to
True
.
See the What’s New Security section above for more details on these changes.
杂项
ContentType.__str__()
now includes the model’sapp_label
to disambiguate models with the same name in different apps.- Because accessing the language in the session rather than in the cookie is deprecated,
LocaleMiddleware
no longer looks for the user’s language in the session and no longer preserves the session’s language after logout. django.utils.html.escape()
now uses to escape HTML. This converts'
to'
instead of the previous equivalent decimal code'
.- The
django-admin test -k
option now works as theunittest -k
option rather than as a shortcut for--keepdb
. - Support for
pywatchman
< 1.2.0 is removed. - now encodes iterable values as they are when
doseq=False
, rather than iterating them, bringing it into line with the standard libraryurllib.parse.urlencode()
function. intword
template filter now translates1.0
as a singular phrase and all other numeric values as plural. This may be incorrect for some languages.- Assigning a value to a model’s or
OneToOneField
'_id'
attribute now unsets the corresponding field. Accessing the field afterwards will result in a query. - now handles an asterisk
'*'
according to RFC 7231#section-7.1.4, i.e. if a list of header field names contains an asterisk, then theVary
header will consist of a single asterisk'*'
. - On MySQL 8.0.16+,
PositiveIntegerField
andPositiveSmallIntegerField
now include a check constraint to prevent negative values in the database. alias=None
is added to the signature of .RegexPattern
, used byre_path()
, no longer returns keyword arguments withNone
values to be passed to the view for the optional named groups that are missing.
django.utils.encoding.force_text()
and smart_text()
The smart_text()
and force_text()
aliases (since Django 2.0) of smart_str()
and force_str()
are deprecated. Ignore this deprecation if your code supports Python 2 as the behavior of smart_str()
and force_str()
is different there.
杂项
django.utils.http.urlquote()
,urlquote_plus()
,urlunquote()
, andurlunquote_plus()
are deprecated in favor of the functions that they’re aliases for: ,quote_plus()
, , andunquote_plus()
.django.utils.translation.ugettext()
,ugettext_lazy()
,ugettext_noop()
,ungettext()
, andungettext_lazy()
are deprecated in favor of the functions that they’re aliases for: ,gettext_lazy()
, ,ngettext()
, and .- To limit creation of sessions and hence favor some caching strategies,
django.views.i18n.set_language()
will stop setting the user’s language in the session in Django 4.0. Since Django 2.1, the language is always stored in the cookie. django.utils.text.unescape_entities()
is deprecated in favor ofhtml.unescape()
. Note that unlikeunescape_entities()
,html.unescape()
evaluates lazy strings immediately.- To avoid possible confusion as to effective scope, the private internal utility
is_safe_url()
is renamed tourl_has_allowed_host_and_scheme()
. That a URL has an allowed host and scheme doesn’t in general imply that it’s “safe”. It may still be quoted incorrectly, for example. Ensure to also use on the path component of untrusted URLs.
Features removed in 3.0
These features have reached the end of their deprecation cycle and are removed in Django 3.0.
- The
django.db.backends.postgresql_psycopg2
module is removed. django.shortcuts.render_to_response()
is removed.- The
DEFAULT_CONTENT_TYPE
setting is removed. HttpRequest.xreadlines()
is removed.- Support for the
context
argument ofField.from_db_value()
andExpression.convert_value()
is removed. - The
field_name
keyword argument ofQuerySet.earliest()
andlatest()
is removed.
See Features deprecated in 2.1 for details on these changes, including how to remove usage of these features.
- The
ForceRHR
GIS function is removed. django.utils.http.cookie_date()
is removed.- is removed.