What's new in Tornado 4.4
=========================

Jul 15, 2016
------------

General
~~~~~~~

* Tornado now requires Python 2.7 or 3.3+; versions 2.6 and 3.2 are no
  longer supported. Pypy3 is still supported even though its latest
  release is mainly based on Python 3.2.
* The `monotonic <https://pypi.python.org/pypi/monotonic>`_ package is
  now supported as an alternative to `Monotime
  <https://pypi.python.org/pypi/Monotime>`_ for monotonic clock support
  on Python 2.

``tornado.curl_httpclient``
~~~~~~~~~~~~~~~~~~~~~~~~~~~

* Failures in ``_curl_setup_request`` no longer cause the
  ``max_clients`` pool to be exhausted.
* Non-ascii header values are now handled correctly.

`tornado.gen`
~~~~~~~~~~~~~

* `.with_timeout` now accepts any yieldable object (except
  ``YieldPoint``), not just `tornado.concurrent.Future`.

`tornado.httpclient`
~~~~~~~~~~~~~~~~~~~~

* The errors raised by timeouts now indicate what state the request
  was in; the error message is no longer simply "599 Timeout".
* Calling `repr` on a `tornado.httpclient.HTTPError` no longer raises
  an error.

`tornado.httpserver`
~~~~~~~~~~~~~~~~~~~~

* Int-like enums (including `http.HTTPStatus`) can now be used as
  status codes.
* Responses with status code ``204 No Content`` no longer emit a
  ``Content-Length: 0`` header.

`tornado.ioloop`
~~~~~~~~~~~~~~~~

* Improved performance when there are large numbers of active timeouts.

`tornado.netutil`
~~~~~~~~~~~~~~~~~

* All included `.Resolver` implementations raise `IOError` (or a
  subclass) for any resolution failure.

`tornado.options`
~~~~~~~~~~~~~~~~~

* Options can now be modified with subscript syntax in addition to
  attribute syntax.
* The special variable ``__file__`` is now available inside config files.

``tornado.simple_httpclient``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* HTTP/1.0 (not 1.1) responses without a ``Content-Length`` header now
  work correctly.

`tornado.tcpserver`
~~~~~~~~~~~~~~~~~~~

* `.TCPServer.bind` now accepts a ``reuse_port`` argument.

`tornado.testing`
~~~~~~~~~~~~~~~~~

* Test sockets now always use ``127.0.0.1`` instead of ``localhost``.
  This avoids conflicts when the automatically-assigned port is
  available on IPv4 but not IPv6, or in unusual network configurations
  when ``localhost`` has multiple IP addresses.

`tornado.web`
~~~~~~~~~~~~~

* ``image/svg+xml`` is now on the list of compressible mime types.
* Fixed an error on Python 3 when compression is used with multiple
  ``Vary`` headers.

`tornado.websocket`
~~~~~~~~~~~~~~~~~~~

* ``WebSocketHandler.__init__`` now uses `super`, which improves
  support for multiple inheritance.
