-------------
Released 2022-08-01
- Remove previously deprecated code. :pr:`4667`
- Old names for some ``send_file`` parameters have been removed.
``download_name`` replaces ``attachment_filename``, ``max_age``
replaces ``cache_timeout``, and ``etag`` replaces ``add_etags``.
Additionally, ``path`` replaces ``filename`` in
``send_from_directory``.
- The ``RequestContext.g`` property returning ``AppContext.g`` is
removed.
- Update Werkzeug dependency to >= 2.2.
- The app and request contexts are managed using Python context vars
directly rather than Werkzeug's ``LocalStack``. This should result
in better performance and memory use. :pr:`4682`
- Extension maintainers, be aware that ``_app_ctx_stack.top``
and ``_request_ctx_stack.top`` are deprecated. Store data on
``g`` instead using a unique prefix, like
``g._extension_name_attr``.
- The ``FLASK_ENV`` environment variable and ``app.env`` attribute are
deprecated, removing the distinction between development and debug
mode. Debug mode should be controlled directly using the ``--debug``
option or ``app.run(debug=True)``. :issue:`4714`
- Some attributes that proxied config keys on ``app`` are deprecated:
``session_cookie_name``, ``send_file_max_age_default``,
``use_x_sendfile``, ``propagate_exceptions``, and
``templates_auto_reload``. Use the relevant config keys instead.
:issue:`4716`
- Add new customization points to the ``Flask`` app object for many
previously global behaviors.
- ``flask.url_for`` will call ``app.url_for``. :issue:`4568`
- ``flask.abort`` will call ``app.aborter``.
``Flask.aborter_class`` and ``Flask.make_aborter`` can be used
to customize this aborter. :issue:`4567`
- ``flask.redirect`` will call ``app.redirect``. :issue:`4569`
- ``flask.json`` is an instance of ``JSONProvider``. A different
provider can be set to use a different JSON library.
``flask.jsonify`` will call ``app.json.response``, other
functions in ``flask.json`` will call corresponding functions in
``app.json``. :pr:`4692`
- JSON configuration is moved to attributes on the default
``app.json`` provider. ``JSON_AS_ASCII``, ``JSON_SORT_KEYS``,
``JSONIFY_MIMETYPE``, and ``JSONIFY_PRETTYPRINT_REGULAR`` are
deprecated. :pr:`4692`
- Setting custom ``json_encoder`` and ``json_decoder`` classes on the
app or a blueprint, and the corresponding ``json.JSONEncoder`` and
``JSONDecoder`` classes, are deprecated. JSON behavior can now be
overridden using the ``app.json`` provider interface. :pr:`4692`
- ``json.htmlsafe_dumps`` and ``json.htmlsafe_dump`` are deprecated,
the function is built-in to Jinja now. :pr:`4692`
- Refactor ``register_error_handler`` to consolidate error checking.
Rewrite some error messages to be more consistent. :issue:`4559`
- Use Blueprint decorators and functions intended for setup after
registering the blueprint will show a warning. In the next version,
this will become an error just like the application setup methods.
:issue:`4571`
- ``before_first_request`` is deprecated. Run setup code when creating
the application instead. :issue:`4605`
- Added the ``View.init_every_request`` class attribute. If a view
subclass sets this to ``False``, the view will not create a new
instance on every request. :issue:`2520`.
- A ``flask.cli.FlaskGroup`` Click group can be nested as a
sub-command in a custom CLI. :issue:`3263`
- Add ``--app`` and ``--debug`` options to the ``flask`` CLI, instead
of requiring that they are set through environment variables.
:issue:`2836`
- Add ``--env-file`` option to the ``flask`` CLI. This allows
specifying a dotenv file to load in addition to ``.env`` and
``.flaskenv``. :issue:`3108`
- It is no longer required to decorate custom CLI commands on
``app.cli`` or ``blueprint.cli`` with ``with_appcontext``, an app
context will already be active at that point. :issue:`2410`
- ``SessionInterface.get_expiration_time`` uses a timezone-aware
value. :pr:`4645`
- View functions can return generators directly instead of wrapping
them in a ``Response``. :pr:`4629`
- Add ``stream_template`` and ``stream_template_string`` functions to
render a template as a stream of pieces. :pr:`4629`
- A new implementation of context preservation during debugging and
testing. :pr:`4666`
- ``request``, ``g``, and other context-locals point to the
correct data when running code in the interactive debugger
console. :issue:`2836`
- Teardown functions are always run at the end of the request,
even if the context is preserved. They are also run after the
preserved context is popped.
- ``stream_with_context`` preserves context separately from a
``with client`` block. It will be cleaned up when
``response.get_data()`` or ``response.close()`` is called.
- Allow returning a list from a view function, to convert it to a
JSON response like a dict is. :issue:`4672`
- When type checking, allow ``TypedDict`` to be returned from view
functions. :pr:`4695`
- Remove the ``--eager-loading/--lazy-loading`` options from the
``flask run`` command. The app is always eager loaded the first
time, then lazily loaded in the reloader. The reloader always prints
errors immediately but continues serving. Remove the internal
``DispatchingApp`` middleware used by the previous implementation.
:issue:`4715`