Announcing Tornado 6.1

[Ben Darnell]

I am pleased to announce the release of Tornado 6.1, available from

https://pypi.org/project/tornado/

Release notes:

https://www.tornadoweb.org/en/stable/releases/v6.1.0.html

Deprecation notice

• This is the last release of Tornado to support Python 3.5. Future versions will require Python 3.6 or newer.

General changes

• Windows support has been improved. Tornado is now compatible with the proactor event loop (which became the default in Python 3.8) by automatically falling back to running a selector in a second thread. This means that it is no longer necessary to explicitly configure a selector event loop, although doing so may improve performance. This does not change the fact that Tornado is significantly less scalable on Windows than on other platforms.
• Binary wheels are now provided for Windows, MacOS, and Linux (amd64 and arm64).

tornado.gen

• coroutine now has better support for the Python 3.7+ contextvars module. In particular, the ContextVar.reset method is now supported.

tornado.http1connection

• HEAD requests to handlers that used chunked encoding no longer produce malformed output.
• Certain kinds of malformed gzip data no longer cause an infinite loop.

tornado.httpclient

• Setting decompress_response=False now works correctly with curl_httpclient.
• Mixing requests with and without proxies works correctly in curl_httpclient (assuming the version of pycurl is recent enough).
• A default User-Agent of Tornado/$VERSION is now used if the user_agent parameter is not specified.
• After a 303 redirect, tornado.simple_httpclient always uses GET. Previously this would use GET if the original request was a POST and would otherwise reuse the original request method. For curl_httpclient, the behavior depends on the version of libcurl (with the most recent versions using GET after 303 regardless of the original method).
• Setting request_timeout and/or connect_timeout to zero is now supported to disable the timeout.

tornado.httputil

• Header parsing is now faster.
• parse_body_arguments now accepts incompletely-escaped non-ASCII inputs.

tornado.iostream

• ssl.CertificateError during the SSL handshake is now handled correctly.
• Reads that are resolved while the stream is closing are now handled correctly.

tornado.log

• When colored logging is enabled, logging.CRITICAL messages are now recognized and colored magenta.

tornado.netutil

• EADDRNOTAVAIL is now ignored when binding to localhost with IPv6. This error is common in docker.

tornado.platform.asyncio

• AnyThreadEventLoopPolicy now also configures a selector event loop for these threads (the proactor event loop only works on the main thread)

tornado.platform.auto

• The set_close_exec function has been removed.

tornado.testing

• ExpectLog now has a level argument to ensure that the given log level is enabled.

tornado.web

• RedirectHandler.get now accepts keyword arguments.
• When sending 304 responses, more headers (including Allow) are now preserved.
• reverse_url correctly handles escaped characters in the regex route.
• Default Etag headers are now generated with SHA-512 instead of MD5.

tornado.websocket

• The ping_interval timer is now stopped when the connection is closed.
• websocket_connect now raises an error when it encounters a redirect instead of hanging.