What’s new in Tornado 4.5.3

Jan 6, 2018

`tornado.curl_httpclient`

Improved debug logging on Python 3.

`tornado.httpserver`

Content-Length and Transfer-Encoding headers are no longer sent with 1xx or 204 responses (this was already true of 304 responses).
Reading chunked requests no longer leaves the connection in a broken state.

`tornado.iostream`

Writing a memoryview can no longer result in “BufferError: Existing exports of data: object cannot be re-sized”.

`tornado.options`

Duplicate option names are now detected properly whether they use hyphens or underscores.

`tornado.testing`

AsyncHTTPTestCase.fetch now uses 127.0.0.1 instead of localhost, improving compatibility with systems that have partially-working ipv6 stacks.

`tornado.web`

It is no longer allowed to send a body with 1xx or 204 responses.

`tornado.websocket`

Requests with invalid websocket headers now get a response with status code 400 instead of a closed connection.