# Django 3.2.11.dev 文档

# Django 1.7 版本发行说明

2014 年 9 月 2 日

Welcome to Django 1.7!

These release notes cover the new features, as well as some backwards incompatible changes you'll want to be aware of when upgrading from Django 1.6 or older versions. We've begun the deprecation process for some features, and some features have reached the end of their deprecation process and have been removed.

## Python 兼容性

Django 1.7 requires Python 2.7, 3.2, 3.3, or 3.4. We highly recommend and only officially support the latest release of each series.

The Django 1.6 series is the last to support Python 2.6. Django 1.7 is the first release to support Python 3.4.

This change should affect only a small number of Django users, as most operating-system vendors today are shipping Python 2.7 or newer as their default version. If you're still using Python 2.6, however, you'll need to stick to Django 1.6 until you can upgrade your Python version. Per our support policy, Django 1.6 will continue to receive security support until the release of Django 1.8.

## What's new in Django 1.7

### Schema migrations

Django now has built-in support for schema migrations. It allows models to be updated, changed, and deleted by creating migration files that represent the model changes and which can be run on any development, staging or production database.

Migrations are covered in their own documentation, but a few of the key features are:

- `syncdb` has been deprecated and replaced by `migrate`. Don't worry - calls to `syncdb` will still work as before.

- A new `makemigrations` command provides an easy way to autodetect changes to your models and make migrations for them.

  `django.db.models.signals.pre_syncdb` and `django.db.models.signals.post_syncdb` have been deprecated, to be replaced by `pre_migrate` and `post_migrate` respectively. These new signals have slightly different arguments. Check the documentation for details.

- The `allow_syncdb` method on database routers is now called `allow_migrate`, but still performs the same function. Routers with `allow_syncdb` methods will still work, but that method name is deprecated and you should change it as soon as possible (nothing more than renaming is required).

- `initial_data` fixtures are no longer loaded for apps with migrations; if you want to load initial data for an app, we suggest you create a migration for your application and define a `RunPython` or `RunSQL` operation in the `operations` section of the migration.

- Test rollback behavior is different for apps with migrations; in particular, Django will no longer emulate rollbacks on non-transactional databases or inside `TransactionTestCase` unless specifically requested.

- It is not advised to have apps without migrations depend on (have a `ForeignKey` or `ManyToManyField` to) apps with migrations.

### App-loading refactor

Historically, Django applications were tightly linked to models. A singleton known as the "app cache" dealt with both installed applications and models. The models module was used as an identifier for applications in many APIs.

As the concept of Django applications matured, this code showed some shortcomings. It has been refactored into an "app registry" where models modules no longer have a central role and where it's possible to attach configuration data to applications.

Improvements thus far include:

- Applications can run code at startup, before Django does anything else, with the `ready()` method of their configuration.
- Application labels are assigned correctly to models even when they're defined outside of `models.py`. You don't have to set `app_label` explicitly any more.
- It is possible to omit `models.py` entirely if an application doesn't have any models.
- Applications can be relabeled with the `label` attribute of application configurations, to work around label conflicts.
- The name of applications can be customized in the admin with the `verbose_name` of application configurations.
- The admin automatically calls `autodiscover()` when Django starts. You can consequently remove this line from your URLconf.
- Django imports all application configurations and models as soon as it starts, through a deterministic and straightforward process. This should make it easier to diagnose import issues such as import loops.

### New method on Field subclasses

To help power both schema migrations and to enable easier addition of composite keys in future releases of Django, the `Field` API now has a new required method: `deconstruct()`.

This method takes no arguments, and returns a tuple of four items:

- `name`: The field's attribute name on its parent model, or `None` if it is not part of a model
- `path`: A dotted, Python path to the class of this field, including the class name.
- `args`: Positional arguments, as a list
- `kwargs`: Keyword arguments, as a dict

These four values allow any field to be serialized into a file, as well as allowing the field to be copied safely, both essential parts of these new features.

This change should not affect you unless you write custom Field subclasses; if you do, you may need to reimplement the `deconstruct()` method if your subclass changes the method signature of `__init__` in any way. If your field just inherits from a built-in Django field and doesn't override `__init__`, no changes are necessary.

If you do need to override `deconstruct()`, a good place to start is the built-in Django fields (`django/db/models/fields/__init__.py`) as several fields, including `DecimalField` and `DateField`, override it and show how to call the method on the superclass and simply add or remove extra arguments.

This also means that all arguments to fields must themselves be serializable; to see what we consider serializable, and to find out how to make your own classes serializable, read the migration serialization documentation.

### Calling custom `QuerySet` methods from the `Manager`

Historically, the recommended way to make reusable model queries was to create methods on a custom `Manager` class. The problem with this approach was that after the first method call, you'd get back a `QuerySet` instance and couldn't call additional custom manager methods.

Though not documented, it was common to work around this issue by creating a custom `QuerySet` so that custom methods could be chained; but the solution had a number of drawbacks:

- The custom `QuerySet` and its custom methods were lost after the first call to `values()` or `values_list()`.
- Writing a custom `Manager` was still necessary to return the custom `QuerySet` class and all methods that were desired on the `Manager` had to be proxied to the `QuerySet`. The whole process went against the DRY principle.

The `QuerySet.as_manager()` class method can now directly create Manager with QuerySet methods:

    class FoodQuerySet(models.QuerySet):
        def pizzas(self):
            return self.filter(kind='pizza')

        def vegetarian(self):
            return self.filter(vegetarian=True)

    class Food(models.Model):
        kind = models.CharField(max_length=50)
        vegetarian = models.BooleanField(default=False)
        objects = FoodQuerySet.as_manager()

    Food.objects.pizzas().vegetarian()

### Using a custom manager when traversing reverse relations

It is now possible to specify a custom manager when traversing a reverse relationship:

    class Blog(models.Model):
        pass

    class Entry(models.Model):
        blog = models.ForeignKey(Blog)

        objects = models.Manager()  # Default Manager
        entries = EntryManager()    # Custom Manager

    b = Blog.objects.get(id=1)
    b.entry_set(manager='entries').all()

### New system check framework

We've added a new System check framework for detecting common problems (like invalid models) and providing hints for resolving those problems. The framework is extensible so you can add your own checks for your own apps and libraries.

To perform system checks, you use the `check` management command. This command replaces the older `validate` management command.

### New `Prefetch` object for advanced `prefetch_related` operations.

The new `Prefetch` object allows customizing prefetch operations.

You can specify the `QuerySet` used to traverse a given relation or customize the storage location of prefetch results.

This enables things like filtering prefetched relations, calling `select_related()` from a prefetched relation, or prefetching the same relation multiple times with different querysets. See `prefetch_related()` for more details.

### Admin shortcuts support time zones

The "today" and "now" shortcuts next to date and time input widgets in the admin are now operating in the current time zone. Previously, they used the browser time zone, which could result in saving the wrong value when it didn't match the current time zone on the server.

In addition, the widgets now display a help message when the browser and server time zone are different, to clarify how the value inserted in the field will be interpreted.

### Using database cursors as context managers

Prior to Python 2.7, database cursors could be used as a context manager. The specific backend's cursor defined the behavior of the context manager. The behavior of magic method lookups was changed with Python 2.7 and cursors were no longer usable as context managers.

Django 1.7 allows a cursor to be used as a context manager. That is, the following can be used:

    with connection.cursor() as c:
        c.execute(...)

替换成：

    c = connection.cursor()
    try:
        c.execute(...)
    finally:
        c.close()

### Custom lookups

It is now possible to write custom lookups and transforms for the ORM. Custom lookups work just like Django's built-in lookups (e.g. `lte`, `icontains`) while transforms are a new concept.

The `django.db.models.Lookup` class provides a way to add lookup operators for model fields. As an example it is possible to add `day_lte` operator for `DateFields`.

The `django.db.models.Transform` class allows transformations of database values prior to the final lookup. For example it is possible to write a `year` transform that extracts year from the field's value. Transforms allow for chaining. After the `year` transform has been added to `DateField` it is possible to filter on the transformed value, for example `qs.filter(author__birthdate__year__lte=1981)`.

For more information about both custom lookups and transforms refer to the custom lookups documentation.

### Improvements to `Form` error handling

#### `Form.add_error()`

Previously there were two main patterns for handling errors in forms:

- Raising a `ValidationError` from within certain functions (e.g. `Field.clean()`, `Form.clean_<fieldname>()`, or `Form.clean()` for non-field errors.)
- Fiddling with `Form._errors` when targeting a specific field in `Form.clean()` or adding errors from outside of a "clean" method (e.g. directly from a view).

Using the former pattern was straightforward since the form can guess from the context (i.e. which method raised the exception) where the errors belong and automatically process them. This remains the canonical way of adding errors when possible. However the latter was fiddly and error-prone, since the burden of handling edge cases fell on the user.

The new `add_error()` method allows adding errors to specific form fields from anywhere without having to worry about the details such as creating instances of `django.forms.utils.ErrorList` or dealing with `Form.cleaned_data`. This new API replaces manipulating `Form._errors` which now becomes a private API.

See 清理和验证相互依赖的字段 for an example using `Form.add_error()`.

#### Error metadata

The `ValidationError` constructor accepts metadata such as error `code` or `params` which are then available for interpolating into the error message (see 引发 ValidationError for more details); however, before Django 1.7 those metadata were discarded as soon as the errors were added to `Form.errors`.

`Form.errors` and `django.forms.utils.ErrorList` now store the `ValidationError` instances so these metadata can be retrieved at any time through the new `Form.errors.as_data` method.

The retrieved `ValidationError` instances can then be identified thanks to their error `code` which enables things like rewriting the error's message or writing custom logic in a view when a given error is present. It can also be used to serialize the errors in a custom format such as XML.

The new `Form.errors.as_json()` method is a convenience method which returns error messages along with error codes serialized as JSON. `as_json()` uses `as_data()` and gives an idea of how the new system could be extended.

#### Error containers and backward compatibility

Heavy changes to the various error containers were necessary in order to support the features above, specifically `Form.errors`, `django.forms.utils.ErrorList`, and the internal storages of `ValidationError`. These containers which used to store error strings now store `ValidationError` instances and public APIs have been adapted to make this as transparent as possible, but if you've been using private APIs, some of the changes are backwards incompatible; see ValidationError constructor and internal storage for more details.

### 次要特性

#### `django.contrib.admin`

- You can now implement `site_header`, `site_title`, and `index_title` attributes on a custom `AdminSite` in order to easily change the admin site's page title and header text. No more needing to override templates!
- Buttons in `django.contrib.admin` now use the `border-radius` CSS property for rounded corners rather than GIF background images.
- Some admin templates now have `app-<app_name>` and `model-<model_name>` classes in their `<body>` tag to allow customizing the CSS per app or per model.
- The admin changelist cells now have a `field-<field_name>` class in the HTML to enable style customizations.
- The admin's search fields can now be customized per-request thanks to the new `django.contrib.admin.ModelAdmin.get_search_fields()` method.
- The `ModelAdmin.get_fields()` method may be overridden to customize the value of `ModelAdmin.fields`.
- In addition to the existing `admin.site.register` syntax, you can use the new `register()` decorator to register a `ModelAdmin`.
- You may specify `ModelAdmin.list_display_links` `= None` to disable links on the change list page grid.
- You may now specify `ModelAdmin.view_on_site` to control whether or not to display the "View on site" link.
- You can specify a descending ordering for a `ModelAdmin.list_display` value by prefixing the `admin_order_field` value with a hyphen.
- The `ModelAdmin.get_changeform_initial_data()` method may be overridden to define custom behavior for setting initial change form data.

#### `django.contrib.auth`

- Any `**kwargs` passed to `email_user()` are passed to the underlying `send_mail()` call.
- The `permission_required()` decorator can take a list of permissions as well as a single permission.
- You can override the new `AuthenticationForm.confirm_login_allowed()` method to more easily customize the login policy.
- `django.contrib.auth.views.password_reset()` takes an optional `html_email_template_name` parameter used to send a multipart HTML email for password resets.
- The `AbstractBaseUser.get_session_auth_hash()` method was added and if your `AUTH_USER_MODEL` inherits from `AbstractBaseUser`, changing a user's password now invalidates old sessions if the `django.contrib.auth.middleware.SessionAuthenticationMiddleware` is enabled. See 密码更改时会话失效 for more details.

#### `django.contrib.formtools`

- Calls to `WizardView.done()` now include a `form_dict` to allow easier access to forms by their step name.

#### `django.contrib.gis`

- The default OpenLayers library version included in widgets has been updated from 2.11 to 2.13.
- Prepared geometries now also support the `crosses`, `disjoint`, `overlaps`, `touches` and `within` predicates, if GEOS 3.3 or later is installed.

#### `django.contrib.messages`

- The backends for `django.contrib.messages` that use cookies, will now follow the `SESSION_COOKIE_SECURE` and `SESSION_COOKIE_HTTPONLY` settings.
- The messages context processor now adds a dictionary of default levels under the name `DEFAULT_MESSAGE_LEVELS`.
- `Message` objects now have a `level_tag` attribute that contains the string representation of the message level.

#### `django.contrib.redirects`

- `RedirectFallbackMiddleware` has two new attributes (`response_gone_class` and `response_redirect_class`) that specify the types of `HttpResponse` instances the middleware returns.

#### `django.contrib.sessions`

- The `"django.contrib.sessions.backends.cached_db"` session backend now respects `SESSION_CACHE_ALIAS`. In previous versions, it always used the `default` cache.

#### `django.contrib.sitemaps`

- The `sitemap framework` now makes use of `lastmod` to set a `Last-Modified` header in the response. This makes it possible for the `ConditionalGetMiddleware` to handle conditional `GET` requests for sitemaps which set `lastmod`.

#### `django.contrib.sites`

- The new `django.contrib.sites.middleware.CurrentSiteMiddleware` allows setting the current site on each request.

#### `django.contrib.staticfiles`

- The static files storage classes may be subclassed to override the permissions that collected static files and directories receive by setting the `file_permissions_mode` and `directory_permissions_mode` parameters. See `collectstatic` for example usage.

- The `CachedStaticFilesStorage` backend gets a sibling class called `ManifestStaticFilesStorage` that doesn't use the cache system at all but instead a JSON file called `staticfiles.json` for storing the mapping between the original file name (e.g. `css/styles.css`) and the hashed file name (e.g. `css/styles.55e7cbb9ba48.css`). The `staticfiles.json` file is created when running the `collectstatic` management command and should be a less expensive alternative for remote storages such as Amazon S3.

  See the `ManifestStaticFilesStorage` docs for more information.

- `findstatic` now accepts verbosity flag level 2, meaning it will show the relative paths of the directories it searched. See `findstatic` for example output.

#### `django.contrib.syndication`

- The `Atom1Feed` syndication feed's `updated` element now utilizes `updateddate` instead of `pubdate`, allowing the `published` element to be included in the feed (which relies on `pubdate`).

#### 缓存

- Access to caches configured in `CACHES` is now available via `django.core.cache.caches`. This dict-like object provides a different instance per thread. It supersedes `django.core.cache.get_cache()` which is now deprecated.
- If you instantiate cache backends directly, be aware that they aren't thread-safe any more, as `django.core.cache.caches` now yields different instances per thread.
- Defining the `TIMEOUT` argument of the `CACHES` setting as `None` will set the cache keys as "non-expiring" by default. Previously, it was only possible to pass `timeout=None` to the cache backend's `set()` method.

#### Cross Site Request Forgery

- The `CSRF_COOKIE_AGE` setting facilitates the use of session-based CSRF cookies.

#### 电子邮件

- `send_mail()` now accepts an `html_message` parameter for sending a multipart text/plain and text/html email.
- The SMTP `EmailBackend` now accepts a `timeout` parameter.

#### 文件存储

- File locking on Windows previously depended on the PyWin32 package; if it wasn't installed, file locking failed silently. That dependency has been removed, and file locking is now implemented natively on both Windows and Unix.

#### 文件上传

- The new `UploadedFile.content_type_extra` attribute contains extra parameters passed to the `content-type` header on a file upload.
- The new `FILE_UPLOAD_DIRECTORY_PERMISSIONS` setting controls the file system permissions of directories created during file upload, like `FILE_UPLOAD_PERMISSIONS` does for the files themselves.
- The `FileField.upload_to` attribute is now optional. If it is omitted or given `None` or an empty string, a subdirectory won't be used for storing the uploaded files.
- Uploaded files are now explicitly closed before the response is delivered to the client. Partially uploaded files are also closed as long as they are named `file` in the upload handler.
- `Storage.get_available_name()` now appends an underscore plus a random 7 character alphanumeric string (e.g. `"_x3a1gho"`), rather than iterating through an underscore followed by a number (e.g. `"_1"`, `"_2"`, etc.) to prevent a denial-of-service attack. This change was also made in the 1.6.6, 1.5.9, and 1.4.14 security releases.

#### 表单

- The `<label>` and `<input>` tags rendered by `RadioSelect` and `CheckboxSelectMultiple` when looping over the radio buttons or checkboxes now include `for` and `id` attributes, respectively. Each radio button or checkbox includes an `id_for_label` attribute to output the element's ID.
- The `<textarea>` tags rendered by `Textarea` now include a `maxlength` attribute if the `TextField` model field has a `max_length`.
- `Field.choices` now allows you to customize the "empty choice" label by including a tuple with an empty string or `None` for the key and the custom label as the value. The default blank option `"----------"` will be omitted in this case.
- `MultiValueField` allows optional subfields by setting the `require_all_fields` argument to `False`. The `required` attribute for each individual field will be respected, and a new `incomplete` validation error will be raised when any required fields are empty.
- The `clean()` method on a form no longer needs to return `self.cleaned_data`. If it does return a changed dictionary then that will still be used.
- After a temporary regression in Django 1.6, it's now possible again to make `TypedChoiceField` `coerce` method return an arbitrary value.
- `SelectDateWidget.months` can be used to customize the wording of the months displayed in the select widget.
- The `min_num` and `validate_min` parameters were added to `formset_factory()` to allow validating a minimum number of submitted forms.
- The metaclasses used by `Form` and `ModelForm` have been reworked to support more inheritance scenarios. The previous limitation that prevented inheriting from both `Form` and `ModelForm` simultaneously have been removed as long as `ModelForm` appears first in the MRO.
- It's now possible to remove a field from a `Form` when subclassing by setting the name to `None`.
- It's now possible to customize the error messages for `ModelForm`’s `unique`, `unique_for_date`, and `unique_together` constraints. In order to support `unique_together` or any other `NON_FIELD_ERROR`, `ModelForm` now looks for the `NON_FIELD_ERROR` key in the `error_messages` dictionary of the `ModelForm`’s inner `Meta` class. See considerations regarding model's error_messages for more details.

#### 国际化

- The `django.middleware.locale.LocaleMiddleware.response_redirect_class` attribute allows you to customize the redirects issued by the middleware.
- The `LocaleMiddleware` now stores the user's selected language with the session key `_language`. This should only be accessed using the `LANGUAGE_SESSION_KEY` constant. Previously it was stored with the key `django_language` and the `LANGUAGE_SESSION_KEY` constant did not exist, but keys reserved for Django should start with an underscore. For backwards compatibility `django_language` is still read from in 1.7. Sessions will be migrated to the new key as they are written.
- The `blocktrans` tag now supports a `trimmed` option. This option will remove newline characters from the beginning and the end of the content of the `{% blocktrans %}` tag, replace any whitespace at the beginning and end of a line and merge all lines into one using a space character to separate them. This is quite useful for indenting the content of a `{% blocktrans %}` tag without having the indentation characters end up in the corresponding entry in the PO file, which makes the translation process easier.
- When you run `makemessages` from the root directory of your project, any extracted strings will now be automatically distributed to the proper app or project message file. See 本地化：如何创建语言文件 for details.
- The `makemessages` command now always adds the `--previous` command line flag to the `msgmerge` command, keeping previously translated strings in po files for fuzzy strings.
- The following settings to adjust the language cookie options were introduced: `LANGUAGE_COOKIE_AGE`, `LANGUAGE_COOKIE_DOMAIN` and `LANGUAGE_COOKIE_PATH`.
- Added 本地格式化 for Esperanto.

#### 管理命令

- The new `--no-color` option for `django-admin` disables the colorization of management command output.

- The new `dumpdata --natural-foreign` and `dumpdata --natural-primary` options, and the new `use_natural_foreign_keys` and `use_natural_primary_keys` arguments for `serializers.serialize()`, allow the use of natural primary keys when serializing.

- It is no longer necessary to provide the cache table name or the `--database` option for the `createcachetable` command. Django takes this information from your settings file. If you have configured multiple caches or multiple databases, all cache tables are created.

- The `runserver` command received several improvements:

  - On Linux systems, if pyinotify is installed, the development server will reload immediately when a file is changed. Previously, it polled the filesystem for changes every second. That caused a small delay before reloads and reduced battery life on laptops.
  - In addition, the development server automatically reloads when a translation file is updated, i.e. after running `compilemessages`.
  - All HTTP requests are logged to the console, including requests for static files or `favicon.ico` that used to be filtered out.

- Management commands can now produce syntax colored output under Windows if the ANSICON third-party tool is installed and active.

- `collectstatic` command with symlink option is now supported on Windows NT 6 (Windows Vista and newer).

- Initial SQL data now works better if the sqlparse Python library is installed.

  Note that it's deprecated in favor of the `RunSQL` operation of migrations, which benefits from the improved behavior.

#### 模型

- The `QuerySet.update_or_create()` method was added.
- The new `default_permissions` model `Meta` option allows you to customize (or disable) creation of the default add, change, and delete permissions.
- Explicit `OneToOneField` for 多表继承 are now discovered in abstract classes.
- It is now possible to avoid creating a backward relation for `OneToOneField` by setting its `related_name` to `'+'` or ending it with `'+'`.
- `F expressions` support the power operator (`**`).
- The `remove()` and `clear()` methods of the related managers created by `ForeignKey` and `GenericForeignKey` now accept the `bulk` keyword argument to control whether or not to perform operations in bulk (i.e. using `QuerySet.update()`). Defaults to `True`.
- It is now possible to use `None` as a query value for the `iexact` lookup.
- It is now possible to pass a callable as value for the attribute `limit_choices_to` when defining a `ForeignKey` or `ManyToManyField`.
- Calling `only()` and `defer()` on the result of `QuerySet.values()` now raises an error (before that, it would either result in a database error or incorrect data).
- You can use a single list for `index_together` (rather than a list of lists) when specifying a single set of fields.
- Custom intermediate models having more than one foreign key to any of the models participating in a many-to-many relationship are now permitted, provided you explicitly specify which foreign keys should be used by setting the new `ManyToManyField.through_fields` argument.
- Assigning a model instance to a non-relation field will now throw an error. Previously this used to work if the field accepted integers as input as it took the primary key.
- Integer fields are now validated against database backend specific min and max values based on their `internal_type`. Previously model field validation didn't prevent values out of their associated column data type range from being saved resulting in an integrity error.
- It is now possible to explicitly `order_by()` a relation `_id` field by using its attribute name.

#### 信号

- The `enter` argument was added to the `setting_changed` signal.
- The model signals can be now be connected to using a `str` of the `'app_label.ModelName'` form – just like related fields – to lazily reference their senders.

#### 模板

- The `Context.push()` method now returns a context manager which automatically calls `pop()` upon exiting the `with` statement. Additionally, `push()` now accepts parameters that are passed to the `dict` constructor used to build the new context level.
- The new `Context.flatten()` method returns a `Context`'s stack as one flat dictionary.
- `Context` objects can now be compared for equality (internally, this uses `Context.flatten()` so the internal structure of each `Context`'s stack doesn't matter as long as their flattened version is identical).
- The `widthratio` template tag now accepts an `"as"` parameter to capture the result in a variable.
- The `include` template tag will now also accept anything with a `render()` method (such as a `Template`) as an argument. String arguments will be looked up using `get_template()` as always.
- It is now possible to `include` templates recursively.
- Template objects now have an origin attribute set when `TEMPLATE_DEBUG` is `True`. This allows template origins to be inspected and logged outside of the `django.template` infrastructure.
- `TypeError` exceptions are no longer silenced when raised during the rendering of a template.
- The following functions now accept a `dirs` parameter which is a list or tuple to override `TEMPLATE_DIRS`:
  - `django.template.loader.get_template()`
  - `django.template.loader.select_template()`
  - `django.shortcuts.render()`
  - `django.shortcuts.render_to_response()`
- The `time` filter now accepts timezone-related format specifiers `'e'`, `'O'` , `'T'` and `'Z'` and is able to digest time-zone-aware `datetime` instances performing the expected rendering.
- The `cache` tag will now try to use the cache called "template_fragments" if it exists and fall back to using the default cache otherwise. It also now accepts an optional `using` keyword argument to control which cache it uses.
- The new `truncatechars_html` filter truncates a string to be no longer than the specified number of characters, taking HTML into account.

#### 请求和响应

- The new `HttpRequest.scheme` attribute specifies the scheme of the request (`http` or `https` normally).
- The shortcut `redirect()` now supports relative URLs.
- The new `JsonResponse` subclass of `HttpResponse` helps easily create JSON-encoded responses.

#### 测试

- `DiscoverRunner` has two new attributes, `test_suite` and `test_runner`, which facilitate overriding the way tests are collected and run.
- The `fetch_redirect_response` argument was added to `assertRedirects()`. Since the test client can't fetch externals URLs, this allows you to use `assertRedirects` with redirects that aren't part of your Django app.
- Correct handling of scheme when making comparisons in `assertRedirects()`.
- The `secure` argument was added to all the request methods of `Client`. If `True`, the request will be made through HTTPS.
- `assertNumQueries()` now prints out the list of executed queries if the assertion fails.
- The `WSGIRequest` instance generated by the test handler is now attached to the `django.test.Response.wsgi_request` attribute.
- The database settings for testing have been collected into a dictionary named `TEST`.

#### 实用程序

- Improved `strip_tags()` accuracy (but it still cannot guarantee an HTML-safe result, as stated in the documentation).

#### 验证器

- `RegexValidator` now accepts the optional `flags` and Boolean `inverse_match` arguments. The `inverse_match` attribute determines if the `ValidationError` should be raised when the regular expression pattern matches (`True`) or does not match (`False`, by default) the provided `value`. The `flags` attribute sets the flags used when compiling a regular expression string.
- `URLValidator` now accepts an optional `schemes` argument which allows customization of the accepted URI schemes (instead of the defaults `http(s)` and `ftp(s)`).
- `validate_email()` now accepts addresses with IPv6 literals, like `example@[2001:db8::1]`, as specified in RFC 5321.

## Backwards incompatible changes in 1.7

警告

In addition to the changes outlined in this section, be sure to review the deprecation plan for any features that have been removed. If you haven't updated your code within the deprecation timeline for a given feature, its removal may appear as a backwards incompatible change.

### `allow_syncdb` / `allow_migrate`

While Django will still look at `allow_syncdb` methods even though they should be renamed to `allow_migrate`, there is a subtle difference in which models get passed to these methods.

For apps with migrations, `allow_migrate` will now get passed historical models, which are special versioned models without custom attributes, methods or managers. Make sure your `allow_migrate` methods are only referring to fields or other items in `model._meta`.

### initial_data

Apps with migrations will not load `initial_data` fixtures when they have finished migrating. Apps without migrations will continue to load these fixtures during the phase of `migrate` which emulates the old `syncdb` behavior, but any new apps will not have this support.

Instead, you are encouraged to load initial data in migrations if you need it (using the `RunPython` operation and your model classes); this has the added advantage that your initial data will not need updating every time you change the schema.

Additionally, like the rest of Django's old `syncdb` code, `initial_data` has been started down the deprecation path and will be removed in Django 1.9.

### deconstruct() and serializability

Django now requires all Field classes and all of their constructor arguments to be serializable. If you modify the constructor signature in your custom Field in any way, you'll need to implement a deconstruct() method; we've expanded the custom field documentation with instructions on implementing this method.

The requirement for all field arguments to be serializable means that any custom class instances being passed into Field constructors - things like custom Storage subclasses, for instance - need to have a deconstruct method defined on them as well, though Django provides a handy class decorator that will work for most applications.

### App-loading changes

#### Start-up sequence

Django 1.7 loads application configurations and models as soon as it starts. While this behavior is more straightforward and is believed to be more robust, regressions cannot be ruled out. See 错误调试 for solutions to some problems you may encounter.

#### 独一无二的脚本

If you're using Django in a plain Python script — rather than a management command — and you rely on the `DJANGO_SETTINGS_MODULE` environment variable, you must now explicitly initialize Django at the beginning of your script with:

    >>> import django
    >>> django.setup()

Otherwise, you will hit an `AppRegistryNotReady` exception.

#### WSGI scripts

Until Django 1.3, the recommended way to create a WSGI application was:

    import django.core.handlers.wsgi
    application = django.core.handlers.wsgi.WSGIHandler()

In Django 1.4, support for WSGI was improved and the API changed to:

    from django.core.wsgi import get_wsgi_application
    application = get_wsgi_application()

If you're still using the former style in your WSGI script, you need to upgrade to the latter, or you will hit an `AppRegistryNotReady` exception.

#### App registry consistency

It is no longer possible to have multiple installed applications with the same label. In previous versions of Django, this didn't always work correctly, but didn't crash outright either.

If you have two apps with the same label, you should create an `AppConfig` for one of them and override its `label` there. You should then adjust your code wherever it references this application or its models with the old label.

It isn't possible to import the same model twice through different paths any more. As of Django 1.6, this may happen only if you're manually putting a directory and a subdirectory on `PYTHONPATH`. Refer to the section on the new project layout in the 1.4 release notes for migration instructions.

You should make sure that:

- All models are defined in applications that are listed in `INSTALLED_APPS` or have an explicit `app_label`.
- Models aren't imported as a side-effect of loading their application. Specifically, you shouldn't import models in the root module of an application nor in the module that define its configuration class.

Django will enforce these requirements as of version 1.9, after a deprecation period.

#### Subclassing AppCommand

Subclasses of `AppCommand` must now implement a `handle_app_config()` method instead of `handle_app()`. This method receives an `AppConfig` instance instead of a models module.

#### Introspecting applications

Since `INSTALLED_APPS` now supports application configuration classes in addition to application modules, you should review code that accesses this setting directly and use the app registry (`django.apps.apps`) instead.

The app registry has preserved some features of the old app cache. Even though the app cache was a private API, obsolete methods and arguments will be removed through a standard deprecation path, with the exception of the following changes that take effect immediately:

- `get_model` raises `LookupError` instead of returning `None` when no model is found.
- The `only_installed` argument of `get_model` and `get_models` no longer exists, nor does the `seed_cache` argument of `get_model`.

### Management commands and order of `INSTALLED_APPS`

When several applications provide management commands with the same name, Django loads the command from the application that comes first in `INSTALLED_APPS`. Previous versions loaded the command from the application that came last.

This brings discovery of management commands in line with other parts of Django that rely on the order of `INSTALLED_APPS`, such as static files, templates, and translations.

### `ValidationError` constructor and internal storage

The behavior of the `ValidationError` constructor has changed when it receives a container of errors as an argument (e.g. a `list` or an `ErrorList`):

- It converts any strings it finds to instances of `ValidationError` before adding them to its internal storage.
- It doesn't store the given container but rather copies its content to its own internal storage; previously the container itself was added to the `ValidationError` instance and used as internal storage.

This means that if you access the `ValidationError` internal storages, such as `error_list`; `error_dict`; or the return value of `update_error_dict()` you may find instances of `ValidationError` where you would have previously found strings.

Also if you directly assigned the return value of `update_error_dict()` to `Form._errors` you may inadvertently add `list` instances where `ErrorList` instances are expected. This is a problem because unlike a simple `list`, an `ErrorList` knows how to handle instances of `ValidationError`.

Most use-cases that warranted using these private APIs are now covered by the newly introduced `Form.add_error()` method:

    # Old pattern:
    try:
        # ...
    except ValidationError as e:
        self._errors = e.update_error_dict(self._errors)

    # New pattern:
    try:
        # ...
    except ValidationError as e:
        self.add_error(None, e)

If you need both Django <= 1.6 and 1.7 compatibility you can't use `Form.add_error()` since it wasn't available before Django 1.7, but you can use the following workaround to convert any `list` into `ErrorList`:

    try:
        # ...
    except ValidationError as e:
        self._errors = e.update_error_dict(self._errors)

    # Additional code to ensure ``ErrorDict`` is exclusively
    # composed of ``ErrorList`` instances.
    for field, error_list in self._errors.items():
        if not isinstance(error_list, self.error_class):
            self._errors[field] = self.error_class(error_list)

### Behavior of `LocMemCache` regarding pickle errors

An inconsistency existed in previous versions of Django regarding how pickle errors are handled by different cache backends. `django.core.cache.backends.locmem.LocMemCache` used to fail silently when such an error occurs, which is inconsistent with other backends and leads to cache-specific errors. This has been fixed in Django 1.7, see #21200 for more details.

### Cache keys are now generated from the request's absolute URL

Previous versions of Django generated cache keys using a request's path and query string but not the scheme or host. If a Django application was serving multiple subdomains or domains, cache keys could collide. In Django 1.7, cache keys vary by the absolute URL of the request including scheme, host, path, and query string. For example, the URL portion of a cache key is now generated from `https://www.example.com/path/to/?key=val` rather than `/path/to/?key=val`. The cache keys generated by Django 1.7 will be different from the keys generated by older versions of Django. After upgrading to Django 1.7, the first request to any previously cached URL will be a cache miss.

### Passing `None` to `Manager.db_manager()`

In previous versions of Django, it was possible to use `db_manager(using=None)` on a model manager instance to obtain a manager instance using default routing behavior, overriding any manually specified database routing. In Django 1.7, a value of `None` passed to db_manager will produce a router that retains any manually assigned database routing -- the manager will not be reset. This was necessary to resolve an inconsistency in the way routing information cascaded over joins. See #13724 for more details.

### pytz may be required

If your project handles datetimes before 1970 or after 2037 and Django raises a `ValueError` when encountering them, you will have to install pytz. You may be affected by this problem if you use Django's time zone-related date formats or `django.contrib.syndication`.

### `remove()` and `clear()` methods of related managers

The `remove()` and `clear()` methods of the related managers created by `ForeignKey`, `GenericForeignKey`, and `ManyToManyField` suffered from a number of issues. Some operations ran multiple data modifying queries without wrapping them in a transaction, and some operations didn't respect default filtering when it was present (i.e. when the default manager on the related model implemented a custom `get_queryset()`).

Fixing the issues introduced some backward incompatible changes:

- The default implementation of `remove()` for `ForeignKey` related managers changed from a series of `Model.save()` calls to a single `QuerySet.update()` call. The change means that `pre_save` and `post_save` signals aren't sent anymore. You can use the `bulk=False` keyword argument to revert to the previous behavior.
- The `remove()` and `clear()` methods for `GenericForeignKey` related managers now perform bulk delete. The `Model.delete()` method isn't called on each instance anymore. You can use the `bulk=False` keyword argument to revert to the previous behavior.
- The `remove()` and `clear()` methods for `ManyToManyField` related managers perform nested queries when filtering is involved, which may or may not be an issue depending on your database and your data itself. See this note for more details.

### Admin login redirection strategy

Historically, the Django admin site passed the request from an unauthorized or unauthenticated user directly to the login view, without HTTP redirection. In Django 1.7, this behavior changed to conform to a more traditional workflow where any unauthorized request to an admin page will be redirected (by HTTP status code 302) to the login page, with the `next` parameter set to the referring path. The user will be redirected there after a successful login.

Note also that the admin login form has been updated to not contain the `this_is_the_login_form` field (now unused) and the `ValidationError` code has been set to the more regular `invalid_login` key.

### `select_for_update()` requires a transaction

Historically, queries that use `select_for_update()` could be executed in autocommit mode, outside of a transaction. Before Django 1.6, Django's automatic transactions mode allowed this to be used to lock records until the next write operation. Django 1.6 introduced database-level autocommit; since then, execution in such a context voids the effect of `select_for_update()`. It is, therefore, assumed now to be an error and raises an exception.

This change was made because such errors can be caused by including an app which expects global transactions (e.g. `ATOMIC_REQUESTS` set to `True`), or Django's old autocommit behavior, in a project which runs without them; and further, such errors may manifest as data-corruption bugs. It was also made in Django 1.6.3.

This change may cause test failures if you use `select_for_update()` in a test class which is a subclass of `TransactionTestCase` rather than `TestCase`.

### Contrib middleware removed from default `MIDDLEWARE_CLASSES`

The app-loading refactor deprecated using models from apps which are not part of the `INSTALLED_APPS` setting. This exposed an incompatibility between the default `INSTALLED_APPS` and `MIDDLEWARE_CLASSES` in the global defaults (`django.conf.global_settings`). To bring these settings in sync and prevent deprecation warnings when doing things like testing reusable apps with minimal settings, `SessionMiddleware`, `AuthenticationMiddleware`, and `MessageMiddleware` were removed from the defaults. These classes will still be included in the default settings generated by `startproject`. Most projects will not be affected by this change but if you were not previously declaring the `MIDDLEWARE_CLASSES` in your project settings and relying on the global default you should ensure that the new defaults are in line with your project's needs. You should also check for any code that accesses `django.conf.global_settings.MIDDLEWARE_CLASSES` directly.

### 杂项

- The `django.core.files.uploadhandler.FileUploadHandler.new_file()` method is now passed an additional `content_type_extra` parameter. If you have a custom `FileUploadHandler` that implements `new_file()`, be sure it accepts this new parameter.

- `ModelFormSet`s no longer delete instances when `save(commit=False)` is called. See `can_delete` for instructions on how to manually delete objects from deleted forms.

- Loading empty fixtures emits a `RuntimeWarning` rather than raising `CommandError`.

- `django.contrib.staticfiles.views.serve()` will now raise an `Http404` exception instead of `ImproperlyConfigured` when `DEBUG` is `False`. This change removes the need to conditionally add the view to your root URLconf, which in turn makes it safe to reverse by name. It also removes the ability for visitors to generate spurious HTTP 500 errors by requesting static files that don't exist or haven't been collected yet.

- The `django.db.models.Model.__eq__()` method is now defined in a way where instances of a proxy model and its base model are considered equal when primary keys match. Previously only instances of exact same class were considered equal on primary key match.

- The `django.db.models.Model.__eq__()` method has changed such that two `Model` instances without primary key values won't be considered equal (unless they are the same instance).

- The `django.db.models.Model.__hash__()` method will now raise `TypeError` when called on an instance without a primary key value. This is done to avoid mutable `__hash__` values in containers.

- `AutoField` columns in SQLite databases will now be created using the `AUTOINCREMENT` option, which guarantees monotonic increments. This will cause primary key numbering behavior to change on SQLite, becoming consistent with most other SQL databases. This will only apply to newly created tables. If you have a database created with an older version of Django, you will need to migrate it to take advantage of this feature. For example, you could do the following:

  1. Use `dumpdata` to save your data.
  2. Rename the existing database file (keep it as a backup).
  3. Run `migrate` to create the updated schema.
  4. Use `loaddata` to import the fixtures you exported in (1).

- `django.contrib.auth.models.AbstractUser` no longer defines a `get_absolute_url()` method. The old definition returned `"/users/%s/" % urlquote(self.username)` which was arbitrary since applications may or may not define such a url in `urlpatterns`. Define a `get_absolute_url()` method on your own custom user object or use `ABSOLUTE_URL_OVERRIDES` if you want a URL for your user.

- The static asset-serving functionality of the `django.test.LiveServerTestCase` class has been simplified: Now it's only able to serve content already present in `STATIC_ROOT` when tests are run. The ability to transparently serve all the static assets (similarly to what one gets with `DEBUG = True` at development-time) has been moved to a new class that lives in the `staticfiles` application (the one actually in charge of such feature): `django.contrib.staticfiles.testing.StaticLiveServerTestCase`. In other words, `LiveServerTestCase` itself is less powerful but at the same time has less magic.

  Rationale behind this is removal of dependency of non-contrib code on contrib applications.

- The old cache URI syntax (e.g. `"locmem://"`) is no longer supported. It still worked, even though it was not documented or officially supported. If you're still using it, please update to the current `CACHES` syntax.

- The default ordering of `Form` fields in case of inheritance has changed to follow normal Python MRO. Fields are now discovered by iterating through the MRO in reverse with the topmost class coming last. This only affects you if you relied on the default field ordering while having fields defined on both the current class and on a parent `Form`.

- The `required` argument of `SelectDateWidget` has been removed. This widget now respects the form field's `is_required` attribute like other widgets.

- `Widget.is_hidden` is now a read-only property, getting its value by introspecting the presence of `input_type == 'hidden'`.

- `select_related()` now chains in the same way as other similar calls like `prefetch_related`. That is, `select_related('foo', 'bar')` is equivalent to `select_related('foo').select_related('bar')`. Previously the latter would have been equivalent to `select_related('bar')`.

- GeoDjango dropped support for GEOS < 3.1.

- The `init_connection_state` method of database backends now executes in autocommit mode (unless you set `AUTOCOMMIT` to `False`). If you maintain a custom database backend, you should check that method.

- The `django.db.backends.BaseDatabaseFeatures.allows_primary_key_0` attribute has been renamed to `allows_auto_pk_0` to better describe it. It's `True` for all database backends included with Django except MySQL which does allow primary keys with value 0. It only forbids autoincrement primary keys with value 0.

- Shadowing model fields defined in a parent model has been forbidden as this creates ambiguity in the expected model behavior. In addition, clashing fields in the model inheritance hierarchy result in a system check error. For example, if you use multi-inheritance, you need to define custom primary key fields on parent models, otherwise the default `id` fields will clash. See 多重继承 for details.

- `django.utils.translation.parse_accept_lang_header()` now returns lowercase locales, instead of the case as it was provided. As locales should be treated case-insensitive this allows us to speed up locale detection.

- `django.utils.translation.get_language_from_path()` and `django.utils.translation.trans_real.get_supported_language_variant()` now no longer have a `supported` argument.

- The `shortcut` view in `django.contrib.contenttypes.views` now supports protocol-relative URLs (e.g. `//example.com`).

- `GenericRelation` now supports an optional `related_query_name` argument. Setting `related_query_name` adds a relation from the related object back to the content type for filtering, ordering and other query operations.

- When running tests on PostgreSQL, the `USER` will need read access to the built-in `postgres` database. This is in lieu of the previous behavior of connecting to the actual non-test database.

- As part of the System check framework, fields, models, and model managers all implement a `check()` method that is registered with the check framework. If you have an existing method called `check()` on one of these objects, you will need to rename it.

- As noted above in the "Cache" section of "Minor Features", defining the `TIMEOUT` argument of the `CACHES` setting as `None` will set the cache keys as "non-expiring". Previously, with the memcache backend, a `TIMEOUT` of `0` would set non-expiring keys, but this was inconsistent with the set-and-expire (i.e. no caching) behavior of `set("key", "value", timeout=0)`. If you want non-expiring keys, please update your settings to use `None` instead of `0` as the latter now designates set-and-expire in the settings as well.

- The `sql*` management commands now respect the `allow_migrate()` method of `DATABASE_ROUTERS`. If you have models synced to non-default databases, use the `--database` flag to get SQL for those models (previously they would always be included in the output).

- Decoding the query string from URLs now falls back to the ISO-8859-1 encoding when the input is not valid UTF-8.

- With the addition of the `django.contrib.auth.middleware.SessionAuthenticationMiddleware` to the default project template (pre-1.7.2 only), a database must be created before accessing a page using `runserver`.

- The addition of the `schemes` argument to `URLValidator` will appear as a backwards-incompatible change if you were previously using a custom regular expression to validate schemes. Any scheme not listed in `schemes` will fail validation, even if the regular expression matches the given URL.

## 在 1.7 中被废弃的功能

### `django.core.cache.get_cache`

`django.core.cache.get_cache` has been supplanted by `django.core.cache.caches`.

### `django.utils.dictconfig`/`django.utils.importlib`

`django.utils.dictconfig` and `django.utils.importlib` were copies of respectively `logging.config` and `importlib` provided for Python versions prior to 2.7. They have been deprecated.

### `django.utils.module_loading.import_by_path`

The current `django.utils.module_loading.import_by_path` function catches `AttributeError`, `ImportError`, and `ValueError` exceptions, and re-raises `ImproperlyConfigured`. Such exception masking makes it needlessly hard to diagnose circular import problems, because it makes it look like the problem comes from inside Django. It has been deprecated in favor of `import_string()`.

### `django.utils.tzinfo`

`django.utils.tzinfo` provided two `tzinfo` subclasses, `LocalTimezone` and `FixedOffset`. They've been deprecated in favor of more correct alternatives provided by `django.utils.timezone`, `django.utils.timezone.get_default_timezone()` and `django.utils.timezone.get_fixed_timezone()`.

### `django.utils.unittest`

`django.utils.unittest` provided uniform access to the `unittest2` library on all Python versions. Since `unittest2` became the standard library's `unittest` module in Python 2.7, and Django 1.7 drops support for older Python versions, this module isn't useful anymore. It has been deprecated. Use `unittest` instead.

### `django.utils.datastructures.SortedDict`

As `OrderedDict` was added to the standard library in Python 2.7, `SortedDict` is no longer needed and has been deprecated.

The two additional, deprecated methods provided by `SortedDict` (`insert()` and `value_for_index()`) have been removed. If you relied on these methods to alter structures like form fields, you should now treat these `OrderedDict`s as immutable objects and override them to change their content.

For example, you might want to override `MyFormClass.base_fields` (although this attribute isn't considered a public API) to change the ordering of fields for all `MyFormClass` instances; or similarly, you could override `self.fields` from inside `MyFormClass.__init__()`, to change the fields for a particular form instance. For example (from Django itself):

    PasswordChangeForm.base_fields = OrderedDict(
        (k, PasswordChangeForm.base_fields[k])
        for k in ['old_password', 'new_password1', 'new_password2']
    )

### Custom SQL location for models package

Previously, if models were organized in a package (`myapp/models/`) rather than simply `myapp/models.py`, Django would look for initial SQL data in `myapp/models/sql/`. This bug has been fixed so that Django will search `myapp/sql/` as documented. After this issue was fixed, migrations were added which deprecates initial SQL data. Thus, while this change still exists, the deprecation is irrelevant as the entire feature will be removed in Django 1.9.

### Reorganization of `django.contrib.sites`

`django.contrib.sites` provides reduced functionality when it isn't in `INSTALLED_APPS`. The app-loading refactor adds some constraints in that situation. As a consequence, two objects were moved, and the old locations are deprecated:

- `RequestSite` now lives in `django.contrib.sites.requests`.
- `get_current_site()` now lives in `django.contrib.sites.shortcuts`.

### `declared_fieldsets` attribute on `ModelAdmin`

`ModelAdmin.declared_fieldsets` has been deprecated. Despite being a private API, it will go through a regular deprecation path. This attribute was mostly used by methods that bypassed `ModelAdmin.get_fieldsets()` but this was considered a bug and has been addressed.

### Reorganization of `django.contrib.contenttypes`

Since `django.contrib.contenttypes.generic` defined both admin and model related objects, an import of this module could trigger unexpected side effects. As a consequence, its contents were split into `contenttypes` submodules and the `django.contrib.contenttypes.generic` module is deprecated:

- `GenericForeignKey` and `GenericRelation` now live in `fields`.
- `BaseGenericInlineFormSet` and `generic_inlineformset_factory()` now live in `forms`.
- `GenericInlineModelAdmin`, `GenericStackedInline` and `GenericTabularInline` now live in `admin`.

### `syncdb`

The `syncdb` command has been deprecated in favor of the new `migrate` command. `migrate` takes the same arguments as `syncdb` used to plus a few more, so it's safe to just change the name you're calling and nothing else.

### `util` modules renamed to `utils`

The following instances of `util.py` in the Django codebase have been renamed to `utils.py` in an effort to unify all util and utils references:

- `django.contrib.admin.util`
- `django.contrib.gis.db.backends.util`
- `django.db.backends.util`
- `django.forms.util`

### `get_formsets` method on `ModelAdmin`

`ModelAdmin.get_formsets` has been deprecated in favor of the new `get_formsets_with_inlines()`, in order to better handle the case of selectively showing inlines on a `ModelAdmin`.

### `IPAddressField`

The `django.db.models.IPAddressField` and `django.forms.IPAddressField` fields have been deprecated in favor of `django.db.models.GenericIPAddressField` and `django.forms.GenericIPAddressField`.

### `BaseMemcachedCache._get_memcache_timeout` method

The `BaseMemcachedCache._get_memcache_timeout()` method has been renamed to `get_backend_timeout()`. Despite being a private API, it will go through the normal deprecation.

### Natural key serialization options

The `--natural` and `-n` options for `dumpdata` have been deprecated. Use `dumpdata --natural-foreign` instead.

Similarly, the `use_natural_keys` argument for `serializers.serialize()` has been deprecated. Use `use_natural_foreign_keys` instead.

### Merging of `POST` and `GET` arguments into `WSGIRequest.REQUEST`

It was already strongly suggested that you use `GET` and `POST` instead of `REQUEST`, because the former are more explicit. The property `REQUEST` is deprecated and will be removed in Django 1.9.

### `django.utils.datastructures.MergeDict` class

`MergeDict` exists primarily to support merging `POST` and `GET` arguments into a `REQUEST` property on `WSGIRequest`. To merge dictionaries, use `dict.update()` instead. The class `MergeDict` is deprecated and will be removed in Django 1.9.

### Language codes `zh-cn`, `zh-tw` and `fy-nl`

The currently used language codes for Simplified Chinese `zh-cn`, Traditional Chinese `zh-tw` and (Western) Frysian `fy-nl` are deprecated and should be replaced by the language codes `zh-hans`, `zh-hant` and `fy` respectively. If you use these language codes, you should rename the locale directories and update your settings to reflect these changes. The deprecated language codes will be removed in Django 1.9.

### `django.utils.functional.memoize` function

The function `memoize` is deprecated and should be replaced by the `functools.lru_cache` decorator (available from Python 3.2 onwards).

Django ships a backport of this decorator for older Python versions and it's available at `django.utils.lru_cache.lru_cache`. The deprecated function will be removed in Django 1.9.

### Geo Sitemaps

Google has retired support for the Geo Sitemaps format. Hence Django support for Geo Sitemaps is deprecated and will be removed in Django 1.8.

### Passing callable arguments to queryset methods

Callable arguments for querysets were an undocumented feature that was unreliable. It's been deprecated and will be removed in Django 1.9.

Callable arguments were evaluated when a queryset was constructed rather than when it was evaluated, thus this feature didn't offer any benefit compared to evaluating arguments before passing them to queryset and created confusion that the arguments may have been evaluated at query time.

### `ADMIN_FOR` setting

The `ADMIN_FOR` feature, part of the admindocs, has been removed. You can remove the setting from your configuration at your convenience.

### `SplitDateTimeWidget` with `DateTimeField`

`SplitDateTimeWidget` support in `DateTimeField` is deprecated, use `SplitDateTimeWidget` with `SplitDateTimeField` instead.

### `validate`

The `validate` management command is deprecated in favor of the `check` command.

### `django.core.management.BaseCommand`

`requires_model_validation` is deprecated in favor of a new `requires_system_checks` flag. If the latter flag is missing, then the value of the former flag is used. Defining both `requires_system_checks` and `requires_model_validation` results in an error.

The `check()` method has replaced the old `validate()` method.

### `ModelAdmin` validators

The `ModelAdmin.validator_class` and `default_validator_class` attributes are deprecated in favor of the new `checks_class` attribute.

The `ModelAdmin.validate()` method is deprecated in favor of `ModelAdmin.check()`.

The `django.contrib.admin.validation` module is deprecated.

### `django.db.backends.DatabaseValidation.validate_field`

This method is deprecated in favor of a new `check_field` method. The functionality required by `check_field()` is the same as that provided by `validate_field()`, but the output format is different. Third-party database backends needing this functionality should provide an implementation of `check_field()`.

### Loading `ssi` and `url` template tags from `future` library

Django 1.3 introduced `{% load ssi from future %}` and `{% load url from future %}` syntax for forward compatibility of the `ssi` and `url` template tags. This syntax is now deprecated and will be removed in Django 1.9. You can simply remove the `{% load ... from future %}` tags.

### `django.utils.text.javascript_quote`

`javascript_quote()` was an undocumented function present in `django.utils.text`. It was used internally in the `javascript_catalog()` view whose implementation was changed to make use of `json.dumps()` instead. If you were relying on this function to provide safe output from untrusted strings, you should use `django.utils.html.escapejs` or the `escapejs` template filter. If all you need is to generate valid JavaScript strings, you can simply use `json.dumps()`.

### `fix_ampersands` utils method and template filter

The `django.utils.html.fix_ampersands` method and the `fix_ampersands` template filter are deprecated, as the escaping of ampersands is already taken care of by Django's standard HTML escaping features. Combining this with `fix_ampersands` would either result in double escaping, or, if the output is assumed to be safe, a risk of introducing XSS vulnerabilities. Along with `fix_ampersands`, `django.utils.html.clean_html` is deprecated, an undocumented function that calls `fix_ampersands`. As this is an accelerated deprecation, `fix_ampersands` and `clean_html` will be removed in Django 1.8.

### Reorganization of database test settings

All database settings with a `TEST_` prefix have been deprecated in favor of entries in a `TEST` dictionary in the database settings. The old settings will be supported until Django 1.9. For backwards compatibility with older versions of Django, you can define both versions of the settings as long as they match.

### FastCGI support

FastCGI support via the `runfcgi` management command will be removed in Django 1.9. Please deploy your project using WSGI.

### Moved objects in `contrib.sites`

Following the app-loading refactor, two objects in `django.contrib.sites.models` needed to be moved because they must be available without importing `django.contrib.sites.models` when `django.contrib.sites` isn't installed. Import `RequestSite` from `django.contrib.sites.requests` and `get_current_site()` from `django.contrib.sites.shortcuts`. The old import locations will work until Django 1.9.

### `django.forms.forms.get_declared_fields()`

Django no longer uses this functional internally. Even though it's a private API, it'll go through the normal deprecation cycle.

### Private Query Lookup APIs

Private APIs `django.db.models.sql.where.WhereNode.make_atom()` and `django.db.models.sql.where.Constraint` are deprecated in favor of the new custom lookups API.

## Features removed in 1.7

These features have reached the end of their deprecation cycle and are removed in Django 1.7. See 在 1.5 中被废弃的功能 for details, including how to remove usage of these features.

- `django.utils.simplejson` is removed.
- `django.utils.itercompat.product` is removed.
- INSTALLED_APPS and TEMPLATE_DIRS are no longer corrected from a plain string into a tuple.
- `HttpResponse`, `SimpleTemplateResponse`, `TemplateResponse`, `render_to_response()`, `index()`, and `sitemap()` no longer take a `mimetype` argument
- `HttpResponse` immediately consumes its content if it's an iterator.
- The `AUTH_PROFILE_MODULE` setting, and the `get_profile()` method on the User model are removed.
- The `cleanup` management command is removed.
- The `daily_cleanup.py` script is removed.
- `select_related()` no longer has a `depth` keyword argument.
- The `get_warnings_state()`/`restore_warnings_state()` functions from `django.test.utils` and the `save_warnings_state()`/ `restore_warnings_state()` django.test.*TestCase are removed.
- The `check_for_test_cookie` method in `AuthenticationForm` is removed.
- The version of `django.contrib.auth.views.password_reset_confirm()` that supports base36 encoded user IDs (`django.contrib.auth.views.password_reset_confirm_uidb36`) is removed.
- The `django.utils.encoding.StrAndUnicode` mix-in is removed.