tornado.wsgi
— Interoperability with other Python frameworks and servers¶
WSGI support for the Tornado web framework.
WSGI is the Python standard for web servers, and allows for interoperability between Tornado and other Python web frameworks and servers. This module provides WSGI support in two ways:
WSGIAdapter
converts atornado.web.Application
to the WSGI application interface. This is useful for running a Tornado app on another HTTP server, such as Google App Engine. See theWSGIAdapter
class documentation for limitations that apply.WSGIContainer
lets you run other WSGI applications and frameworks on the Tornado HTTP server. For example, with this class you can mix Django and Tornado handlers in a single server.
Running Tornado apps on WSGI servers¶
-
class
tornado.wsgi.
WSGIAdapter
(application)[source]¶ Converts a
tornado.web.Application
instance into a WSGI application.Example usage:
import tornado.web import tornado.wsgi import wsgiref.simple_server class MainHandler(tornado.web.RequestHandler): def get(self): self.write("Hello, world") if __name__ == "__main__": application = tornado.web.Application([ (r"/", MainHandler), ]) wsgi_app = tornado.wsgi.WSGIAdapter(application) server = wsgiref.simple_server.make_server('', 8888, wsgi_app) server.serve_forever()
See the appengine demo for an example of using this module to run a Tornado app on Google App Engine.
In WSGI mode asynchronous methods are not supported. This means that it is not possible to use
AsyncHTTPClient
, or thetornado.auth
ortornado.websocket
modules.In multithreaded WSGI servers on Python 3, it may be necessary to permit
asyncio
to create event loops on any thread. Run the following at startup (typically import time for WSGI applications):import asyncio from tornado.platform.asyncio import AnyThreadEventLoopPolicy asyncio.set_event_loop_policy(AnyThreadEventLoopPolicy())
New in version 4.0.
Deprecated since version 5.1: This class is deprecated and will be removed in Tornado 6.0. Use Tornado’s
HTTPServer
instead of a WSGI container.
-
class
tornado.wsgi.
WSGIApplication
(handlers=None, default_host=None, transforms=None, **settings)[source]¶ A WSGI equivalent of
tornado.web.Application
.Deprecated since version 4.0: Use a regular
Application
and wrap it inWSGIAdapter
instead. This class will be removed in Tornado 6.0.
Running WSGI apps on Tornado servers¶
-
class
tornado.wsgi.
WSGIContainer
(wsgi_application)[source]¶ Makes a WSGI-compatible function runnable on Tornado’s HTTP server.
Warning
WSGI is a synchronous interface, while Tornado’s concurrency model is based on single-threaded asynchronous execution. This means that running a WSGI app with Tornado’s
WSGIContainer
is less scalable than running the same app in a multi-threaded WSGI server likegunicorn
oruwsgi
. UseWSGIContainer
only when there are benefits to combining Tornado and WSGI in the same process that outweigh the reduced scalability.Wrap a WSGI function in a
WSGIContainer
and pass it toHTTPServer
to run it. For example:def simple_app(environ, start_response): status = "200 OK" response_headers = [("Content-type", "text/plain")] start_response(status, response_headers) return ["Hello world!\n"] container = tornado.wsgi.WSGIContainer(simple_app) http_server = tornado.httpserver.HTTPServer(container) http_server.listen(8888) tornado.ioloop.IOLoop.current().start()
This class is intended to let other frameworks (Django, web.py, etc) run on the Tornado HTTP server and I/O loop.
The
tornado.web.FallbackHandler
class is often useful for mixing Tornado and WSGI apps in the same server. See https://github.com/bdarnell/django-tornado-demo for a complete example.-
static
environ
(request)[source]¶ Converts a
tornado.httputil.HTTPServerRequest
to a WSGI environment.
-
static