Tornado is a Python web framework and asynchronous networking library, originally developed at FriendFeed. By using non-blocking network I/O, Tornado can scale to tens of thousands of open connections, making it ideal for long polling, WebSockets, and other applications that require a long-lived connection to each user.
Here is a simple "Hello, world" example web app for Tornado:
import tornado.ioloop import tornado.web class MainHandler(tornado.web.RequestHandler): def get(self): self.write("Hello, world") application = tornado.web.Application([ (r"/", MainHandler), ]) if __name__ == "__main__": application.listen(8888) tornado.ioloop.IOLoop.instance().start()
This example does not use any of Tornado's asynchronous features; for that see this simple chat room.
pip install tornado
Tornado is listed in PyPI and
can be installed with
easy_install. Note that the
source distribution includes demo applications that are not present
when Tornado is installed in this way, so you may wish to download a
copy of the source tarball as well.
Manual installation: Download the latest source from PyPI.
tar xvzf tornado-$VERSION.tar.gz cd tornado-$VERSION python setup.py build sudo python setup.py install
The Tornado source code is hosted on GitHub.
Prerequisites: Tornado runs on Python 2.6, 2.7, 3.2, and 3.3. It has no strict dependencies outside the Python standard library, although some features may require one of the following libraries:
tornado.netutil.ThreadedResolver. It is needed only on Python 2; Python 3 includes this package in the standard library.
tornado.curl_httpclient. Libcurl version 7.18.2 or higher is required; version 7.21.1 or higher is recommended.
Platforms: Tornado should run on any Unix-like platform, although
for the best performance and scalability only Linux (with
and BSD (with
kqueue) are recommended (even though Mac OS X is
derived from BSD and supports kqueue, its networking performance is
generally poor so it is recommended only for development use).
This web site and all documentation is licensed under Creative Commons 3.0.