What’s new in Tornado 2.1

Sep 20, 2011

Support for secure cookies written by pre-1.0 releases of Tornado has been removed. The RequestHandler.get_secure_cookie method no longer takes an include_name parameter.
The debug application setting now causes stack traces to be displayed in the browser on uncaught exceptions. Since this may leak sensitive information, debug mode is not recommended for public-facing servers.

Diginotar has been removed from the default CA certificates file used by SimpleAsyncHTTPClient.

tornado.gen: A generator-based interface to simplify writing asynchronous functions.
tornado.netutil: Parts of tornado.httpserver have been extracted into a new module for use with non-HTTP protocols.
tornado.platform.twisted: A bridge between the Tornado IOLoop and the Twisted Reactor, allowing code written for Twisted to be run on Tornado.
tornado.process: Multi-process mode has been improved, and can now restart crashed child processes. A new entry point has been added at tornado.process.fork_processes, although tornado.httpserver.HTTPServer.start is still supported.

tornado.web.RequestHandler.write_error replaces get_error_html as the preferred way to generate custom error pages (get_error_html is still supported, but deprecated)
In tornado.web.Application, handlers may be specified by (fully-qualified) name instead of importing and passing the class object itself.
It is now possible to use a custom subclass of StaticFileHandler with the static_handler_class application setting, and this subclass can override the behavior of the static_url method.
StaticFileHandler subclasses can now override get_cache_time to customize cache control behavior.
tornado.web.RequestHandler.get_secure_cookie now has a max_age_days parameter to allow applications to override the default one-month expiration.
set_cookie now accepts a max_age keyword argument to set the max-age cookie attribute (note underscore vs dash)
tornado.web.RequestHandler.set_default_headers may be overridden to set headers in a way that does not get reset during error handling.
RequestHandler.add_header can now be used to set a header that can appear multiple times in the response.
RequestHandler.flush can now take a callback for flow control.
The application/json content type can now be gzipped.
The cookie-signing functions are now accessible as static functions tornado.web.create_signed_value and tornado.web.decode_signed_value.

To facilitate some advanced multi-process scenarios, HTTPServer has a new method add_sockets, and socket-opening code is available separately as tornado.netutil.bind_sockets.
The cookies property is now available on tornado.httpserver.HTTPRequest (it is also available in its old location as a property of RequestHandler)
tornado.httpserver.HTTPServer.bind now takes a backlog argument with the same meaning as socket.listen.
HTTPServer can now be run on a unix socket as well as TCP.
Fixed exception at startup when socket.AI_ADDRCONFIG is not available, as on Windows XP

IOStream performance has been improved, especially for small synchronous requests.
New methods tornado.iostream.IOStream.read_until_close and tornado.iostream.IOStream.read_until_regex.
IOStream.read_bytes and IOStream.read_until_close now take a streaming_callback argument to return data as it is received rather than all at once.
IOLoop.add_timeout now accepts datetime.timedelta objects in addition to absolute timestamps.
PeriodicCallback now sticks to the specified period instead of creeping later due to accumulated errors.
tornado.ioloop.IOLoop and tornado.httpclient.HTTPClient now have close() methods that should be used in applications that create and destroy many of these objects.
IOLoop.install can now be used to use a custom subclass of IOLoop as the singleton without monkey-patching.
IOStream should now always call the close callback instead of the connect callback on a connection error.
The IOStream close callback will no longer be called while there are pending read callbacks that can be satisfied with buffered data.

Now supports client SSL certificates with the client_key and client_cert parameters to tornado.httpclient.HTTPRequest
Now takes a maximum buffer size, to allow reading files larger than 100MB
Now works with HTTP 1.0 servers that don’t send a Content-Length header
The allow_nonstandard_methods flag on HTTP client requests now permits methods other than POST and PUT to contain bodies.
Fixed file descriptor leaks and multiple callback invocations in SimpleAsyncHTTPClient
No longer consumes extra connection resources when following redirects.
Now works with buggy web servers that separate headers with \n instead of \r\n\r\n.
Now sets response.request_time correctly.
Connect timeouts now work correctly.

tornado.auth.OpenIdMixin now uses the correct realm when the callback URI is on a different domain.
tornado.autoreload has a new command-line interface which can be used to wrap any script. This replaces the --autoreload argument to tornado.testing.main and is more robust against syntax errors.
tornado.autoreload.watch can be used to watch files other than the sources of imported modules.
tornado.database.Connection has new variants of execute and executemany that return the number of rows affected instead of the last inserted row id.
tornado.locale.load_translations now accepts any properly-formatted locale name, not just those in the predefined LOCALE_NAMES list.
tornado.options.define now takes a group parameter to group options in --help output.
Template loaders now take a namespace constructor argument to add entries to the template namespace.
tornado.websocket now supports the latest (“hybi-10”) version of the protocol (the old version, “hixie-76” is still supported; the correct version is detected automatically).
tornado.websocket now works on Python 3

Windows support has been improved. Windows is still not an officially supported platform, but the test suite now passes and tornado.autoreload works.
Uploading files whose names contain special characters will now work.
Cookie values containing special characters are now properly quoted and unquoted.
Multi-line headers are now supported.
Repeated Content-Length headers (which may be added by certain proxies) are now supported in HTTPServer.
Unicode string literals now work in template expressions.
The template {% module %} directive now works even if applications use a template variable named modules.
Requests with “Expect: 100-continue” now work on python 3