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#!/usr/bin/env python
# Copyright 2009 Facebook
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""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:
* `WSGIApplication` is a version of `tornado.web.Application` that can run
inside a WSGI server. This is useful for running a Tornado app on another
HTTP server, such as Google App Engine. See the `WSGIApplication` 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.
from __future__ import absolute_import, division, print_function, with_statement
import sys
import time
import tornado
from tornado import escape
from tornado import httputil
from tornado.log import access_log
from tornado import web
from tornado.escape import native_str, parse_qs_bytes
from tornado.util import bytes_type, unicode_type
from io import BytesIO # python 3
except ImportError:
from cStringIO import StringIO as BytesIO # python 2
import Cookie # py2
except ImportError:
import http.cookies as Cookie # py3
import urllib.parse as urllib_parse # py3
except ImportError:
import urllib as urllib_parse
# PEP 3333 specifies that WSGI on python 3 generally deals with byte strings
# that are smuggled inside objects of type unicode (via the latin1 encoding).
# These functions are like those in the tornado.escape module, but defined
# here to minimize the temptation to use them in non-wsgi contexts.
if str is unicode_type:
def to_wsgi_str(s):
assert isinstance(s, bytes_type)
return s.decode('latin1')
def from_wsgi_str(s):
assert isinstance(s, str)
return s.encode('latin1')
def to_wsgi_str(s):
assert isinstance(s, bytes_type)
return s
def from_wsgi_str(s):
assert isinstance(s, str)
return s
class WSGIApplication(web.Application):
"""A WSGI equivalent of `tornado.web.Application`.
`WSGIApplication` is very similar to `tornado.web.Application`,
except no asynchronous methods are supported (since WSGI does not
support non-blocking requests properly). If you call
``self.flush()`` or other asynchronous methods in your request
handlers running in a `WSGIApplication`, we throw an exception.
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.wsgi.WSGIApplication([
(r"/", MainHandler),
server = wsgiref.simple_server.make_server('', 8888, application)
See the `appengine demo
for an example of using this module to run a Tornado app on Google
App Engine.
WSGI applications use the same `.RequestHandler` class, but not
``@asynchronous`` methods or ``flush()``. This means that it is
not possible to use `.AsyncHTTPClient`, or the `tornado.auth` or
`tornado.websocket` modules.
def __init__(self, handlers=None, default_host="", **settings):
web.Application.__init__(self, handlers, default_host, transforms=[],
wsgi=True, **settings)
def __call__(self, environ, start_response):
handler = web.Application.__call__(self, HTTPRequest(environ))
assert handler._finished
reason = handler._reason
status = str(handler._status_code) + " " + reason
headers = list(handler._headers.get_all())
if hasattr(handler, "_new_cookie"):
for cookie in handler._new_cookie.values():
headers.append(("Set-Cookie", cookie.OutputString(None)))
[(native_str(k), native_str(v)) for (k, v) in headers])
return handler._write_buffer
class HTTPRequest(object):
"""Mimics `tornado.httpserver.HTTPRequest` for WSGI applications."""
def __init__(self, environ):
"""Parses the given WSGI environment to construct the request."""
self.method = environ["REQUEST_METHOD"]
self.path = urllib_parse.quote(from_wsgi_str(environ.get("SCRIPT_NAME", "")))
self.path += urllib_parse.quote(from_wsgi_str(environ.get("PATH_INFO", "")))
self.uri = self.path
self.arguments = {}
self.query = environ.get("QUERY_STRING", "")
if self.query:
self.uri += "?" + self.query
self.arguments = parse_qs_bytes(native_str(self.query),
self.version = "HTTP/1.1"
self.headers = httputil.HTTPHeaders()
if environ.get("CONTENT_TYPE"):
self.headers["Content-Type"] = environ["CONTENT_TYPE"]
if environ.get("CONTENT_LENGTH"):
self.headers["Content-Length"] = environ["CONTENT_LENGTH"]
for key in environ:
if key.startswith("HTTP_"):
self.headers[key[5:].replace("_", "-")] = environ[key]
if self.headers.get("Content-Length"):
self.body = environ["wsgi.input"].read(
self.body = ""
self.protocol = environ["wsgi.url_scheme"]
self.remote_ip = environ.get("REMOTE_ADDR", "")
if environ.get("HTTP_HOST"): = environ["HTTP_HOST"]
else: = environ["SERVER_NAME"]
# Parse request body
self.files = {}
httputil.parse_body_arguments(self.headers.get("Content-Type", ""),
self.body, self.arguments, self.files)
self._start_time = time.time()
self._finish_time = None
def supports_http_1_1(self):
"""Returns True if this request supports HTTP/1.1 semantics"""
return self.version == "HTTP/1.1"
def cookies(self):
"""A dictionary of Cookie.Morsel objects."""
if not hasattr(self, "_cookies"):
self._cookies = Cookie.SimpleCookie()
if "Cookie" in self.headers:
except Exception:
self._cookies = None
return self._cookies
def full_url(self):
"""Reconstructs the full URL for this request."""
return self.protocol + "://" + + self.uri
def request_time(self):
"""Returns the amount of time it took for this request to execute."""
if self._finish_time is None:
return time.time() - self._start_time
return self._finish_time - self._start_time
class WSGIContainer(object):
r"""Makes a WSGI-compatible function runnable on Tornado's HTTP server.
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.
def __init__(self, wsgi_application):
self.wsgi_application = wsgi_application
def __call__(self, request):
data = {}
response = []
def start_response(status, response_headers, exc_info=None):
data["status"] = status
data["headers"] = response_headers
return response.append
app_response = self.wsgi_application(
WSGIContainer.environ(request), start_response)
body = b"".join(response)
if hasattr(app_response, "close"):
if not data:
raise Exception("WSGI app did not call start_response")
status_code = int(data["status"].split()[0])
headers = data["headers"]
header_set = set(k.lower() for (k, v) in headers)
body = escape.utf8(body)
if status_code != 304:
if "content-length" not in header_set:
headers.append(("Content-Length", str(len(body))))
if "content-type" not in header_set:
headers.append(("Content-Type", "text/html; charset=UTF-8"))
if "server" not in header_set:
headers.append(("Server", "TornadoServer/%s" % tornado.version))
parts = [escape.utf8("HTTP/1.1 " + data["status"] + "\r\n")]
for key, value in headers:
parts.append(escape.utf8(key) + b": " + escape.utf8(value) + b"\r\n")
self._log(status_code, request)
def environ(request):
"""Converts a `tornado.httpserver.HTTPRequest` to a WSGI environment.
hostport =":")
if len(hostport) == 2:
host = hostport[0]
port = int(hostport[1])
host =
port = 443 if request.protocol == "https" else 80
environ = {
"REQUEST_METHOD": request.method,
"PATH_INFO": to_wsgi_str(escape.url_unescape(request.path, encoding=None)),
"QUERY_STRING": request.query,
"REMOTE_ADDR": request.remote_ip,
"SERVER_NAME": host,
"SERVER_PORT": str(port),
"SERVER_PROTOCOL": request.version,
"wsgi.version": (1, 0),
"wsgi.url_scheme": request.protocol,
"wsgi.input": BytesIO(escape.utf8(request.body)),
"wsgi.errors": sys.stderr,
"wsgi.multithread": False,
"wsgi.multiprocess": True,
"wsgi.run_once": False,
if "Content-Type" in request.headers:
environ["CONTENT_TYPE"] = request.headers.pop("Content-Type")
if "Content-Length" in request.headers:
environ["CONTENT_LENGTH"] = request.headers.pop("Content-Length")
for key, value in request.headers.items():
environ["HTTP_" + key.replace("-", "_").upper()] = value
return environ
def _log(self, status_code, request):
if status_code < 400:
log_method =
elif status_code < 500:
log_method = access_log.warning
log_method = access_log.error
request_time = 1000.0 * request.request_time()
summary = request.method + " " + request.uri + " (" + \
request.remote_ip + ")"
log_method("%d %s %.2fms", status_code, summary, request_time)
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