443 lines
21 KiB
ReStructuredText
443 lines
21 KiB
ReStructuredText
What's new in Tornado 3.0
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=========================
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Mar 29, 2013
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------------
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Highlights
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^^^^^^^^^^
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* The ``callback`` argument to many asynchronous methods is now
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optional, and these methods return a `.Future`. The `tornado.gen`
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module now understands ``Futures``, and these methods can be used
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directly without a `.gen.Task` wrapper.
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* New function `.IOLoop.current` returns the `.IOLoop` that is running
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on the current thread (as opposed to `.IOLoop.instance`, which
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returns a specific thread's (usually the main thread's) IOLoop.
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* New class `tornado.netutil.Resolver` provides an asynchronous
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interface to DNS resolution. The default implementation is still
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blocking, but non-blocking implementations are available using one
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of three optional dependencies: `~tornado.netutil.ThreadedResolver`
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using the `concurrent.futures` thread pool,
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``tornado.platform.caresresolver.CaresResolver`` using the ``pycares``
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library, or ``tornado.platform.twisted.TwistedResolver`` using ``twisted``
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* Tornado's logging is now less noisy, and it no longer goes directly
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to the root logger, allowing for finer-grained configuration.
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* New class `tornado.process.Subprocess` wraps `subprocess.Popen` with
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`.PipeIOStream` access to the child's file descriptors.
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* `.IOLoop` now has a static `configure <.Configurable.configure>`
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method like the one on `.AsyncHTTPClient`, which can be used to
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select an `.IOLoop` implementation other than the default.
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* `.IOLoop` can now optionally use a monotonic clock if available
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(see below for more details).
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Backwards-incompatible changes
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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* Python 2.5 is no longer supported. Python 3 is now supported in a single
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codebase instead of using ``2to3``
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* The ``tornado.database`` module has been removed. It is now available
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as a separate package, `torndb <https://github.com/bdarnell/torndb>`_
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* Functions that take an ``io_loop`` parameter now default to
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`.IOLoop.current()` instead of `.IOLoop.instance()`.
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* Empty HTTP request arguments are no longer ignored. This applies to
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``HTTPRequest.arguments`` and ``RequestHandler.get_argument[s]``
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in WSGI and non-WSGI modes.
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* On Python 3, `tornado.escape.json_encode` no longer accepts byte strings.
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* On Python 3, the ``get_authenticated_user`` methods in `tornado.auth`
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now return character strings instead of byte strings.
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* ``tornado.netutil.TCPServer`` has moved to its own module,
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`tornado.tcpserver`.
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* The Tornado test suite now requires ``unittest2`` when run on Python 2.6.
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* `tornado.options.options` is no longer a subclass of `dict`; attribute-style
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access is now required.
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Detailed changes by module
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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Multiple modules
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~~~~~~~~~~~~~~~~
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* Tornado no longer logs to the root logger. Details on the new logging
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scheme can be found under the `tornado.log` module. Note that in some
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cases this will require that you add an explicit logging configuration
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in order to see any output (perhaps just calling ``logging.basicConfig()``),
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although both `.IOLoop.start()` and `tornado.options.parse_command_line`
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will do this for you.
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* On python 3.2+, methods that take an ``ssl_options`` argument (on
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`.SSLIOStream`, `.TCPServer`, and `.HTTPServer`) now accept either a
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dictionary of options or an `ssl.SSLContext` object.
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* New optional dependency on `concurrent.futures` to provide better support
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for working with threads. `concurrent.futures` is in the standard library
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for Python 3.2+, and can be installed on older versions with
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``pip install futures``.
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`tornado.autoreload`
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~~~~~~~~~~~~~~~~~~~~
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* `tornado.autoreload` is now more reliable when there are errors at import
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time.
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* Calling `tornado.autoreload.start` (or creating an `.Application` with
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``debug=True``) twice on the same `.IOLoop` now does nothing (instead of
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creating multiple periodic callbacks). Starting autoreload on
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more than one `.IOLoop` in the same process now logs a warning.
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* Scripts run by autoreload no longer inherit ``__future__`` imports
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used by Tornado.
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`tornado.auth`
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~~~~~~~~~~~~~~
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* On Python 3, the ``get_authenticated_user`` method family now returns
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character strings instead of byte strings.
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* Asynchronous methods defined in `tornado.auth` now return a
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`.Future`, and their ``callback`` argument is optional. The
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``Future`` interface is preferred as it offers better error handling
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(the previous interface just logged a warning and returned None).
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* The `tornado.auth` mixin classes now define a method
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``get_auth_http_client``, which can be overridden to use a non-default
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`.AsyncHTTPClient` instance (e.g. to use a different `.IOLoop`)
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* Subclasses of `.OAuthMixin` are encouraged to override
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`.OAuthMixin._oauth_get_user_future` instead of ``_oauth_get_user``,
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although both methods are still supported.
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`tornado.concurrent`
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~~~~~~~~~~~~~~~~~~~~
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* New module `tornado.concurrent` contains code to support working with
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`concurrent.futures`, or to emulate future-based interface when that module
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is not available.
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``tornado.curl_httpclient``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* Preliminary support for ``tornado.curl_httpclient`` on Python 3. The latest
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official release of pycurl only supports Python 2, but Ubuntu has a
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port available in 12.10 (``apt-get install python3-pycurl``). This port
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currently has bugs that prevent it from handling arbitrary binary data
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but it should work for textual (utf8) resources.
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* Fix a crash with libcurl 7.29.0 if a curl object is created and closed
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without being used.
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`tornado.escape`
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~~~~~~~~~~~~~~~~
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* On Python 3, `~tornado.escape.json_encode` no longer accepts byte strings.
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This mirrors the behavior of the underlying json module. Python 2 behavior
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is unchanged but should be faster.
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`tornado.gen`
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~~~~~~~~~~~~~
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* New decorator ``@gen.coroutine`` is available as an alternative to
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``@gen.engine``. It automatically returns a
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`.Future`, and within the function instead of
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calling a callback you return a value with ``raise
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gen.Return(value)`` (or simply ``return value`` in Python 3.3).
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* Generators may now yield `.Future` objects.
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* Callbacks produced by `.gen.Callback` and `.gen.Task` are now automatically
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stack-context-wrapped, to minimize the risk of context leaks when used
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with asynchronous functions that don't do their own wrapping.
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* Fixed a memory leak involving generators, `.RequestHandler.flush`,
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and clients closing connections while output is being written.
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* Yielding a large list no longer has quadratic performance.
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`tornado.httpclient`
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~~~~~~~~~~~~~~~~~~~~
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* `.AsyncHTTPClient.fetch` now returns a `.Future` and its callback argument
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is optional. When the future interface is used, any error will be raised
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automatically, as if `.HTTPResponse.rethrow` was called.
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* `.AsyncHTTPClient.configure` and all `.AsyncHTTPClient` constructors
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now take a ``defaults`` keyword argument. This argument should be a
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dictionary, and its values will be used in place of corresponding
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attributes of `~tornado.httpclient.HTTPRequest` that are not set.
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* All unset attributes of `tornado.httpclient.HTTPRequest` are now
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``None``. The default values of some attributes
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(``connect_timeout``, ``request_timeout``, ``follow_redirects``,
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``max_redirects``, ``use_gzip``, ``proxy_password``,
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``allow_nonstandard_methods``, and ``validate_cert`` have been moved
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from `~tornado.httpclient.HTTPRequest` to the client
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implementations.
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* The ``max_clients`` argument to `.AsyncHTTPClient` is now a keyword-only
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argument.
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* Keyword arguments to `.AsyncHTTPClient.configure` are no longer used
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when instantiating an implementation subclass directly.
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* Secondary `.AsyncHTTPClient` callbacks (``streaming_callback``,
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``header_callback``, and ``prepare_curl_callback``) now respect
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`.StackContext`.
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`tornado.httpserver`
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~~~~~~~~~~~~~~~~~~~~
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* `.HTTPServer` no longer logs an error when it is unable to read a second
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request from an HTTP 1.1 keep-alive connection.
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* `.HTTPServer` now takes a ``protocol`` keyword argument which can be set
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to ``https`` if the server is behind an SSL-decoding proxy that does not
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set any supported X-headers.
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* ``tornado.httpserver.HTTPConnection`` now has a ``set_close_callback``
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method that should be used instead of reaching into its ``stream``
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attribute.
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* Empty HTTP request arguments are no longer ignored. This applies to
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``HTTPRequest.arguments`` and ``RequestHandler.get_argument[s]``
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in WSGI and non-WSGI modes.
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`tornado.ioloop`
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~~~~~~~~~~~~~~~~
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* New function `.IOLoop.current` returns the ``IOLoop`` that is running
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on the current thread (as opposed to `.IOLoop.instance`, which returns a
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specific thread's (usually the main thread's) IOLoop).
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* New method `.IOLoop.add_future` to run a callback on the IOLoop when
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an asynchronous `.Future` finishes.
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* `.IOLoop` now has a static `configure <.Configurable.configure>`
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method like the one on `.AsyncHTTPClient`, which can be used to
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select an `.IOLoop` implementation other than the default.
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* The `.IOLoop` poller implementations (``select``, ``epoll``, ``kqueue``)
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are now available as distinct subclasses of `.IOLoop`. Instantiating
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`.IOLoop` will continue to automatically choose the best available
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implementation.
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* The `.IOLoop` constructor has a new keyword argument ``time_func``,
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which can be used to set the time function used when scheduling callbacks.
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This is most useful with the `time.monotonic` function, introduced
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in Python 3.3 and backported to older versions via the ``monotime``
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module. Using a monotonic clock here avoids problems when the system
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clock is changed.
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* New function `.IOLoop.time` returns the current time according to the
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IOLoop. To use the new monotonic clock functionality, all calls to
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`.IOLoop.add_timeout` must be either pass a `datetime.timedelta` or
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a time relative to `.IOLoop.time`, not `time.time`. (`time.time` will
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continue to work only as long as the IOLoop's ``time_func`` argument
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is not used).
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* New convenience method `.IOLoop.run_sync` can be used to start an IOLoop
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just long enough to run a single coroutine.
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* New method `.IOLoop.add_callback_from_signal` is safe to use in a signal
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handler (the regular `.add_callback` method may deadlock).
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* `.IOLoop` now uses `signal.set_wakeup_fd` where available (Python 2.6+
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on Unix) to avoid a race condition that could result in Python signal
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handlers being delayed.
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* Method ``IOLoop.running()`` has been removed.
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* `.IOLoop` has been refactored to better support subclassing.
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* `.IOLoop.add_callback` and `.add_callback_from_signal` now take
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``*args, **kwargs`` to pass along to the callback.
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`tornado.iostream`
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~~~~~~~~~~~~~~~~~~
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* `.IOStream.connect` now has an optional ``server_hostname`` argument
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which will be used for SSL certificate validation when applicable.
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Additionally, when supported (on Python 3.2+), this hostname
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will be sent via SNI (and this is supported by ``tornado.simple_httpclient``)
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* Much of `.IOStream` has been refactored into a separate class
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`.BaseIOStream`.
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* New class `tornado.iostream.PipeIOStream` provides the IOStream
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interface on pipe file descriptors.
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* `.IOStream` now raises a new exception
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``tornado.iostream.StreamClosedError`` when you attempt to read or
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write after the stream has been closed (by either side).
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* `.IOStream` now simply closes the connection when it gets an
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``ECONNRESET`` error, rather than logging it as an error.
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* ``IOStream.error`` no longer picks up unrelated exceptions.
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* `.BaseIOStream.close` now has an ``exc_info`` argument (similar to the
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one used in the `logging` module) that can be used to set the stream's
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``error`` attribute when closing it.
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* `.BaseIOStream.read_until_close` now works correctly when it is called
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while there is buffered data.
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* Fixed a major performance regression when run on PyPy (introduced in
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Tornado 2.3).
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`tornado.log`
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~~~~~~~~~~~~~
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* New module containing `.enable_pretty_logging` and `.LogFormatter`,
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moved from the options module.
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* `.LogFormatter` now handles non-ascii data in messages and tracebacks better.
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`tornado.netutil`
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~~~~~~~~~~~~~~~~~
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* New class `tornado.netutil.Resolver` provides an asynchronous
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interface to DNS resolution. The default implementation is still
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blocking, but non-blocking implementations are available using one
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of three optional dependencies: `~tornado.netutil.ThreadedResolver`
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using the `concurrent.futures` thread pool,
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`tornado.platform.caresresolver.CaresResolver` using the ``pycares``
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library, or `tornado.platform.twisted.TwistedResolver` using ``twisted``
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* New function `tornado.netutil.is_valid_ip` returns true if a given string
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is a valid IP (v4 or v6) address.
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* `tornado.netutil.bind_sockets` has a new ``flags`` argument that can
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be used to pass additional flags to ``getaddrinfo``.
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* `tornado.netutil.bind_sockets` no longer sets ``AI_ADDRCONFIG``; this will
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cause it to bind to both ipv4 and ipv6 more often than before.
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* `tornado.netutil.bind_sockets` now works when Python was compiled
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with ``--disable-ipv6`` but IPv6 DNS resolution is available on the
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system.
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* ``tornado.netutil.TCPServer`` has moved to its own module, `tornado.tcpserver`.
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`tornado.options`
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~~~~~~~~~~~~~~~~~
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* The class underlying the functions in `tornado.options` is now public
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(`tornado.options.OptionParser`). This can be used to create multiple
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independent option sets, such as for subcommands.
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* `tornado.options.parse_config_file` now configures logging automatically
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by default, in the same way that `~tornado.options.parse_command_line` does.
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* New function `tornado.options.add_parse_callback` schedules a callback
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to be run after the command line or config file has been parsed. The
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keyword argument ``final=False`` can be used on either parsing function
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to supress these callbacks.
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* `tornado.options.define` now takes a ``callback`` argument. This callback
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will be run with the new value whenever the option is changed. This is
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especially useful for options that set other options, such as by reading
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from a config file.
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* `tornado.options.parse_command_line` ``--help`` output now goes to ``stderr``
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rather than ``stdout``.
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* `tornado.options.options` is no longer a subclass of `dict`; attribute-style
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access is now required.
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* `tornado.options.options` (and `.OptionParser` instances generally) now
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have a `.mockable()` method that returns a wrapper object compatible with
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`mock.patch <unittest.mock.patch>`.
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* Function ``tornado.options.enable_pretty_logging`` has been moved to the
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`tornado.log` module.
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`tornado.platform.caresresolver`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* New module containing an asynchronous implementation of the `.Resolver`
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interface, using the ``pycares`` library.
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`tornado.platform.twisted`
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~~~~~~~~~~~~~~~~~~~~~~~~~~
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* New class `tornado.platform.twisted.TwistedIOLoop` allows Tornado
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code to be run on the Twisted reactor (as opposed to the existing
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`.TornadoReactor`, which bridges the gap in the other direction).
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* New class `tornado.platform.twisted.TwistedResolver` is an asynchronous
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implementation of the `.Resolver` interface.
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`tornado.process`
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~~~~~~~~~~~~~~~~~
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* New class `tornado.process.Subprocess` wraps `subprocess.Popen` with
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`.PipeIOStream` access to the child's file descriptors.
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``tornado.simple_httpclient``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* ``SimpleAsyncHTTPClient`` now takes a ``resolver`` keyword argument
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(which may be passed to either the constructor or `configure
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<.Configurable.configure>`), to allow it to use the new non-blocking
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`tornado.netutil.Resolver`.
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* When following redirects, ``SimpleAsyncHTTPClient`` now treats a 302
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response code the same as a 303. This is contrary to the HTTP spec
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but consistent with all browsers and other major HTTP clients
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(including ``CurlAsyncHTTPClient``).
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* The behavior of ``header_callback`` with ``SimpleAsyncHTTPClient`` has
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changed and is now the same as that of ``CurlAsyncHTTPClient``. The
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header callback now receives the first line of the response (e.g.
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``HTTP/1.0 200 OK``) and the final empty line.
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* ``tornado.simple_httpclient`` now accepts responses with a 304
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status code that include a ``Content-Length`` header.
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* Fixed a bug in which ``SimpleAsyncHTTPClient`` callbacks were being run in the
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client's ``stack_context``.
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`tornado.stack_context`
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~~~~~~~~~~~~~~~~~~~~~~~
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* `.stack_context.wrap` now runs the wrapped callback in a more consistent
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environment by recreating contexts even if they already exist on the
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stack.
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* Fixed a bug in which stack contexts could leak from one callback
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chain to another.
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* Yield statements inside a ``with`` statement can cause stack
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contexts to become inconsistent; an exception will now be raised
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when this case is detected.
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`tornado.template`
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~~~~~~~~~~~~~~~~~~
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* Errors while rendering templates no longer log the generated code,
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since the enhanced stack traces (from version 2.1) should make this
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unnecessary.
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* The ``{% apply %}`` directive now works properly with functions that return
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both unicode strings and byte strings (previously only byte strings were
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supported).
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* Code in templates is no longer affected by Tornado's ``__future__`` imports
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(which previously included ``absolute_import`` and ``division``).
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`tornado.testing`
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~~~~~~~~~~~~~~~~~
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* New function `tornado.testing.bind_unused_port` both chooses a port
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and binds a socket to it, so there is no risk of another process
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using the same port. ``get_unused_port`` is now deprecated.
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* New decorator `tornado.testing.gen_test` can be used to allow for
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yielding `tornado.gen` objects in tests, as an alternative to the
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``stop`` and ``wait`` methods of `.AsyncTestCase`.
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* `tornado.testing.AsyncTestCase` and friends now extend ``unittest2.TestCase``
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when it is available (and continue to use the standard ``unittest`` module
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when ``unittest2`` is not available)
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* `tornado.testing.ExpectLog` can be used as a finer-grained alternative
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to `tornado.testing.LogTrapTestCase`
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* The command-line interface to `tornado.testing.main` now supports
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additional arguments from the underlying `unittest` module:
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``verbose``, ``quiet``, ``failfast``, ``catch``, ``buffer``.
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* The deprecated ``--autoreload`` option of `tornado.testing.main` has
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been removed. Use ``python -m tornado.autoreload`` as a prefix command
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instead.
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* The ``--httpclient`` option of `tornado.testing.main` has been moved
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to ``tornado.test.runtests`` so as not to pollute the application
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option namespace. The `tornado.options` module's new callback
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support now makes it easy to add options from a wrapper script
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instead of putting all possible options in `tornado.testing.main`.
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* `.AsyncHTTPTestCase` no longer calls `.AsyncHTTPClient.close` for tests
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that use the singleton `.IOLoop.instance`.
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* `.LogTrapTestCase` no longer fails when run in unknown logging
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configurations. This allows tests to be run under nose, which does its
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own log buffering (`.LogTrapTestCase` doesn't do anything useful in this
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case, but at least it doesn't break things any more).
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``tornado.util``
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~~~~~~~~~~~~~~~~
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* ``tornado.util.b`` (which was only intended for internal use) is gone.
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`tornado.web`
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~~~~~~~~~~~~~
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* `.RequestHandler.set_header` now overwrites previous header values
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case-insensitively.
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* `tornado.web.RequestHandler` has new attributes ``path_args`` and
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``path_kwargs``, which contain the positional and keyword arguments
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that are passed to the ``get``/``post``/etc method. These attributes
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are set before those methods are called, so they are available during
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``prepare()``
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* `tornado.web.ErrorHandler` no longer requires XSRF tokens on ``POST``
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requests, so posts to an unknown url will always return 404 instead of
|
|
complaining about XSRF tokens.
|
|
* Several methods related to HTTP status codes now take a ``reason`` keyword
|
|
argument to specify an alternate "reason" string (i.e. the "Not Found" in
|
|
"HTTP/1.1 404 Not Found"). It is now possible to set status codes other
|
|
than those defined in the spec, as long as a reason string is given.
|
|
* The ``Date`` HTTP header is now set by default on all responses.
|
|
* ``Etag``/``If-None-Match`` requests now work with `.StaticFileHandler`.
|
|
* `.StaticFileHandler` no longer sets ``Cache-Control: public`` unnecessarily.
|
|
* When gzip is enabled in a `tornado.web.Application`, appropriate
|
|
``Vary: Accept-Encoding`` headers are now sent.
|
|
* It is no longer necessary to pass all handlers for a host in a single
|
|
`.Application.add_handlers` call. Now the request will be matched
|
|
against the handlers for any ``host_pattern`` that includes the request's
|
|
``Host`` header.
|
|
|
|
`tornado.websocket`
|
|
~~~~~~~~~~~~~~~~~~~
|
|
|
|
* Client-side WebSocket support is now available:
|
|
`tornado.websocket.websocket_connect`
|
|
* `.WebSocketHandler` has new methods `~.WebSocketHandler.ping` and
|
|
`~.WebSocketHandler.on_pong` to send pings to the browser (not
|
|
supported on the ``draft76`` protocol)
|