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 via the WSGIContainer class, which makes it possible to run applications using other WSGI frameworks on the Tornado HTTP server. The reverse is not supported; the Tornado Application and RequestHandler classes are designed for use with the Tornado HTTPServer and cannot be used in a generic WSGI container.

class tornado.wsgi.WSGIContainer(wsgi_application: WSGIAppType)[source]

Makes a WSGI-compatible function runnable on Tornado’s HTTP server.


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 like gunicorn or uwsgi. Use WSGIContainer 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 to HTTPServer 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)

This class is intended to let other frameworks (Django,, 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 for a complete example.

static environ(request: tornado.httputil.HTTPServerRequest) → Dict[str, Any][source]

Converts a tornado.httputil.HTTPServerRequest to a WSGI environment.