What’s new in Tornado 6.4.0

Nov 28, 2023

General Changes

• Python 3.12 is now supported. Older versions of Tornado will work on Python 3.12 but may log deprecation warnings.

Deprecation Notices

• IOLoop.add_callback_from_signal is suspected to have been broken since Tornado 5.0 and will be removed in version 7.0. Use asyncio.loop.add_signal_handler instead.

• The client_secret argument to OAuth2Mixin.authorize_redirect is deprecated and will be removed in Tornado 7.0. This argument has never been used and other similar methods in this module don’t have it.

• TwitterMixin is deprecated and will be removed in the future.

tornado.auth

• The client_secret argument to OAuth2Mixin.authorize_redirect is deprecated and will be removed in Tornado 7.0. This argument has never been used and other similar methods in this module don’t have it.

• TwitterMixin is deprecated and will be removed in the future.

tornado.autoreload

• Autoreload can now be used when the program is run as a directory rather than a file or module.

• New CLI flag --until-success re-runs the program on any failure but stops after the first successful run.

tornado.concurrent

• Fixed reference cycles that could lead to increased memory usage.

tornado.escape

• Several methods in this module now simply pass through to their equivalents in the standard library.

tornado.gen

• This module now holds a strong reference to all running asyncio.Task objects it creates. This prevents premature garbage collection which could cause warnings like “Task was destroyed but it is pending!”.

tornado.ioloop

• IOLoop.add_callback_from_signal is suspected to have been broken since Tornado 5.0 and will be removed in version 7.0. Use asyncio.loop.add_signal_handler instead.

• The type annotation for IOLoop.run_in_executor has been updated to match the updated signature of asyncio.loop.run_in_executor.

• Fixed reference cycles that could lead to increased memory usage.

tornado.locale

• format_timestamp now supports “aware” datetime objects.

tornado.platform.asyncio

• The shutdown protocol for AddThreadSelectorEventLoop now requires the use of asyncio.run or asyncio.loop.shutdown_asyncgens to avoid leaking the thread.

• Introduced SelectorThread class containing the core functionality of AddThreadSelectorEventLoop.

• The close() method of AddThreadSelectorEventLoop is now idempotent.

tornado.web

• StaticFileHandler.get_modified_time now supports “aware” datetime objects and the default implementation now returns aware objects.

tornado.websocket

• Unclosed client connections now reliably log a warning. Previously the warning was dependent on garbage collection and whether the ping_interval option was used.

• The subprotocols argument to WebSocketClientConnection now defaults to None instead of an empty list (which was mutable and reused)