Django 3.0 版本发行说明

    Welcome to Django 3.0!

    These release notes cover the new features, as well as some you’ll want to be aware of when upgrading from Django 2.2 or earlier. We’ve dropped some features that have reached the end of their deprecation cycle, and we’ve .

    如果你要更新现有的项目，请看 How to upgrade Django to a newer version 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 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 documentation on deploying with ASGI 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 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 in ModelAdmin.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.

    • The new reset_url_token attribute in PasswordResetConfirmView allows specifying a token parameter displayed as a component of password reset URLs.
    • Added class to ease customization of authentication backends.
    • Added get_user_permissions() method to mirror the existing method.
    • Added HTML autocomplete attribute to widgets of username, email, and password fields in django.contrib.auth.forms for better interaction with browser password managers.
    • 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 UserManager.with_perm() 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 in Distance.
    • The setting now supports pathlib.Path.
    • The class now accepts pathlib.Path path.

    django.contrib.postgres

    • The new helps to avoid typos in SQL operators that can be used together with RangeField.
    • The new expression represents the range boundaries.
    • The new AddIndexConcurrently and classes allow creating and dropping indexes CONCURRENTLY on PostgreSQL.

    django.contrib.syndication

    • Added the language class attribute to the to customize a feed language. The default value is get_language() instead of .

    缓存

    • and never_cache() now add the private directive to Cache-Control headers.

    文件存储

    • The new Storage.get_alternative_name() method allows customizing the algorithm for generating filenames if a file with the uploaded name already exists.

    表单

    国际化

    • Added the LANGUAGE_COOKIE_HTTPONLY, , and LANGUAGE_COOKIE_SECURE settings to set the HttpOnly, SameSite, and Secure 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 of AdminEmailHandler allows providing an django.views.debug.ExceptionReporter subclass to customize the traceback text sent to site when DEBUG is False.

    管理命令

    • The new compilemessages —ignore option allows ignoring specific directories when searching for .po files to compile.
    • now shows the applied datetimes when --verbosity is 2 and above.
    • On PostgreSQL, dbshell now supports client-side TLS certificates.
    • now introspects OneToOneField when a foreign key has a unique or primary key constraint.
    • The new option skips running system checks prior to running the command.
    • The startapp —template and 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, , and SHA512.

    • Added the database function.

    • The new is_dst parameter of the Trunc database functions determines the treatment of nonexistent and ambiguous datetimes.

    • connection.queries now shows COPY … 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 the distinct argument.

    • Added SmallAutoField which acts much like an except that it only allows values under a certain (database-dependent) limit. Values from 1 to 32767 are safe in all databases supported by Django.

    • AutoField, , and SmallAutoField now inherit from IntegerField, BigIntegerField and SmallIntegerField 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 of django.db.backends.base.BaseDatabaseFeatures allows optimization of GROUP 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 to be initialized with memoryview content.
    • For use in, for example, Django templates, now allows lookups using underscores (e.g. user_agent) in place of hyphens.

    安全

    • now defaults to 'DENY'. In older versions, the X_FRAME_OPTIONS setting defaults to 'SAMEORIGIN'. If your site uses frames of itself, you will need to explicitly set X_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 argument raise_request_exception allows controlling whether or not exceptions raised during the request should also be raised in the test. The value defaults to for backwards compatibility. If it is False and an exception occurs, the test client will return a 500 response with the attribute exc_info, 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 option.
    • HTML comparison, as used by assertHTMLEqual(), 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, set DatabaseFeatures.can_create_inline_fk = False.
    • DatabaseFeatures.can_return_id_from_insert and can_return_ids_from_bulk_insert are renamed to can_return_columns_from_insert and can_return_rows_from_bulk_insert.
    • Database functions now handle datetime.timezone formats when created using instances (e.g. timezone(timedelta(hours=5)), which would output 'UTC+05:00'). Third-party backends should handle this format when preparing DateTimeField in datetime_cast_date_sql(), datetime_extract_sql(), etc.
    • Entries for AutoField, BigAutoField, and SmallAutoField are added to DatabaseOperations.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 by fetch_returned_insert_columns() which returns a list of values returned by the INSERT … RETURNING statement, instead of a single value.
    • DatabaseOperations.return_insert_id() is replaced by return_insert_columns() that accepts a fields 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.

    django.contrib.gis

    • 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() - Use instead.
    • django.utils.lru_cache.lru_cache() - Alias of functools.lru_cache().
    • django.utils.decorators.available_attrs() - This function returns functools.WRAPPER_ASSIGNMENTS.
    • django.utils.decorators.ContextDecorator - Alias of .
    • django.utils._os.abspathu() - Alias of os.path.abspath().
    • django.utils._os.upath() and npath() - These functions do nothing on Python 3.
    • django.utils.six - Remove usage of this vendored library or switch to .
    • django.utils.encoding.python_2_unicode_compatible() - Alias of six.python_2_unicode_compatible().
    • django.utils.functional.curry() - Use functools.partial() or . See 5b1c389603a353625ae1603ba345147356336afb.
    • 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:

    See the What’s New above for more details on these changes.

    杂项

    • ContentType.__str__() now includes the model’s app_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 the unittest -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 library urllib.parse.urlencode() function.
    • intword template filter now translates 1.0 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 afterward 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 the Vary header will consist of a single asterisk '*'.
    • On MySQL 8.0.16+, PositiveIntegerField and PositiveSmallIntegerField now include a check constraint to prevent negative values in the database.
    • alias=None is added to the signature of .
    • RegexPattern, used by re_path(), no longer returns keyword arguments with None 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(), and urlunquote_plus() are deprecated in favor of the functions that they’re aliases for: , quote_plus(), , and unquote_plus().
    • django.utils.translation.ugettext(), ugettext_lazy(), ugettext_noop(), ungettext(), and ungettext_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 of html.unescape(). Note that unlike unescape_entities(), html.unescape() evaluates lazy strings immediately.
    • To avoid possible confusion as to effective scope, the private internal utility is_safe_url() is renamed to url_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 of Field.from_db_value() and Expression.convert_value() is removed.
    • The field_name keyword argument of QuerySet.earliest() and latest() is removed.

    See 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.