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What’s new in Tornado 1.2

Feb 20, 2011

We are pleased to announce the release of Tornado 1.2, available from

Backwards compatibility notes:
* This release includes the backwards-incompatible security change from
  version 1.1.1.  Users upgrading from 1.1 or earlier should read the
  release notes from that release:
* StackContexts that do something other than catch exceptions may need to
  be modified to be reentrant.
* When XSRF tokens are used, the token must also be present on PUT and
  DELETE requests (anything but GET and HEAD)

New features:
* A new HTTP client implementation is available in the module
  tornado.simple_httpclient.  This HTTP client does not depend on pycurl.
  It has not yet been tested extensively in production, but is intended
  to eventually replace the pycurl-based HTTP client in a future release of
  Tornado.  To transparently replace tornado.httpclient.AsyncHTTPClient with
  this new implementation, you can set the environment variable
  USE_SIMPLE_HTTPCLIENT=1 (note that the next release of Tornado will
  likely include a different way to select HTTP client implementations)
* Request logging is now done by the Application rather than the
  RequestHandler.  Logging behavior may be customized by either overriding
  Application.log_request in a subclass or by passing log_function
  as an Application setting
* Application.listen(port): Convenience method as an alternative to
  explicitly creating an HTTPServer
* tornado.escape.linkify(): Wrap urls in <a> tags
* RequestHandler.create_signed_value(): Create signatures like the
  secure_cookie methods without setting cookies.
* tornado.testing.get_unused_port(): Returns a port selected in the same
  way as inAsyncHTTPTestCase
* AsyncHTTPTestCase.fetch(): Convenience method for synchronous fetches
* IOLoop.set_blocking_signal_threshold(): Set a callback to be run when
  the IOLoop is blocked.
* IOStream.connect(): Asynchronously connect a client socket
* AsyncHTTPClient.handle_callback_exception(): May be overridden
  in subclass for custom error handling
* httpclient.HTTPRequest has two new keyword arguments, validate_cert and
  ca_certs. Setting validate_cert=False will disable all certificate checks
  when fetching https urls.  ca_certs may be set to a filename containing
  trusted certificate authorities (defaults will be used if this is
* HTTPRequest.get_ssl_certificate(): Returns the client's SSL certificate
  (if client certificates were requested in the server's ssl_options
* StaticFileHandler can be configured to return a default file (e.g.
  index.html) when a directory is requested
* Template directives of the form "{% from x import y %}" are now
  supported (in addition to the existing support for "{% import x
* FacebookGraphMixin.get_authenticated_user now accepts a new
  parameter 'extra_fields' which may be used to request additional
  information about the user

Bug fixes:
* auth: Fixed KeyError with Facebook offline_access
* auth: Uses request.uri instead of request.path as the default redirect
  so that parameters are preserved.
* escape: xhtml_escape() now returns a unicode string, not
  utf8-encoded bytes
* ioloop: Callbacks added with add_callback are now run in the order they
  were added
* ioloop: PeriodicCallback.stop can now be called from inside the callback.
* iostream: Fixed several bugs in SSLIOStream
* iostream: Detect when the other side has closed the connection even with
  the select()-based IOLoop
* iostream: read_bytes(0) now works as expected
* iostream: Fixed bug when writing large amounts of data on windows
* iostream: Fixed infinite loop that could occur with unhandled exceptions
* httpclient: Fix bugs when some requests use proxies and others don't
* httpserver: HTTPRequest.protocol is now set correctly when using the
  built-in SSL support
* httpserver: When using multiple processes, the standard library's
  random number generator is re-seeded in each child process
* httpserver: With xheaders enabled, X-Forwarded-Proto is supported as an
  alternative to X-Scheme
* httpserver: Fixed bugs in multipart/form-data parsing
* locale: format_date() now behaves sanely with dates in the future
* locale: Updates to the language list
* stack_context: Fixed bug with contexts leaking through reused IOStreams
* stack_context: Simplified semantics and improved performance
* web: The order of css_files from UIModules is now preserved
* web: Fixed error with default_host redirect
* web: StaticFileHandler works when os.path.sep != '/' (i.e. on Windows)
* web: Fixed a caching-related bug in StaticFileHandler when a file's
  timestamp has changed but its contents have not.
* web: Fixed bugs with HEAD requests and e.g. Etag headers
* web: Fix bugs when different handlers have different static_paths
* web: @removeslash will no longer cause a redirect loop when applied to the
  root path
* websocket: Now works over SSL
* websocket: Improved compatibility with proxies

Many thanks to everyone who contributed patches, bug reports, and feedback
that went into this release!