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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.
"""A non-blocking, single-threaded HTTP server.
Typical applications have little direct interaction with the `HTTPServer`
class except to start a server at the beginning of the process
(and even that is often done indirectly via `tornado.web.Application.listen`).
This module also defines the `HTTPRequest` class which is exposed via
import Cookie
import logging
import socket
import time
import urlparse
from tornado.escape import utf8, native_str, parse_qs_bytes
from tornado import httputil
from tornado import iostream
from tornado.netutil import TCPServer
from tornado import stack_context
from tornado.util import b, bytes_type
import ssl # Python 2.6+
except ImportError:
ssl = None
class HTTPServer(TCPServer):
r"""A non-blocking, single-threaded HTTP server.
A server is defined by a request callback that takes an HTTPRequest
instance as an argument and writes a valid HTTP response with
`HTTPRequest.write`. `HTTPRequest.finish` finishes the request (but does
not necessarily close the connection in the case of HTTP/1.1 keep-alive
requests). A simple example server that echoes back the URI you
import httpserver
import ioloop
def handle_request(request):
message = "You requested %s\n" % request.uri
request.write("HTTP/1.1 200 OK\r\nContent-Length: %d\r\n\r\n%s" % (
len(message), message))
http_server = httpserver.HTTPServer(handle_request)
`HTTPServer` is a very basic connection handler. Beyond parsing the
HTTP request body and headers, the only HTTP semantics implemented
in `HTTPServer` is HTTP/1.1 keep-alive connections. We do not, however,
implement chunked encoding, so the request callback must provide a
``Content-Length`` header or implement chunked encoding for HTTP/1.1
requests for the server to run correctly for HTTP/1.1 clients. If
the request handler is unable to do this, you can provide the
``no_keep_alive`` argument to the `HTTPServer` constructor, which will
ensure the connection is closed on every request no matter what HTTP
version the client is using.
If ``xheaders`` is ``True``, we support the ``X-Real-Ip`` and ``X-Scheme``
headers, which override the remote IP and HTTP scheme for all requests.
These headers are useful when running Tornado behind a reverse proxy or
load balancer.
`HTTPServer` can serve SSL traffic with Python 2.6+ and OpenSSL.
To make this server serve SSL traffic, send the ssl_options dictionary
argument with the arguments required for the `ssl.wrap_socket` method,
including "certfile" and "keyfile"::
HTTPServer(applicaton, ssl_options={
"certfile": os.path.join(data_dir, "mydomain.crt"),
"keyfile": os.path.join(data_dir, "mydomain.key"),
`HTTPServer` initialization follows one of three patterns (the
initialization methods are defined on `tornado.netutil.TCPServer`):
1. `~tornado.netutil.TCPServer.listen`: simple single-process::
server = HTTPServer(app)
In many cases, `tornado.web.Application.listen` can be used to avoid
the need to explicitly create the `HTTPServer`.
2. `~tornado.netutil.TCPServer.bind`/`~tornado.netutil.TCPServer.start`:
simple multi-process::
server = HTTPServer(app)
server.start(0) # Forks multiple sub-processes
When using this interface, an `IOLoop` must *not* be passed
to the `HTTPServer` constructor. `start` will always start
the server on the default singleton `IOLoop`.
3. `~tornado.netutil.TCPServer.add_sockets`: advanced multi-process::
sockets = tornado.netutil.bind_sockets(8888)
server = HTTPServer(app)
The `add_sockets` interface is more complicated, but it can be
used with `tornado.process.fork_processes` to give you more
flexibility in when the fork happens. `add_sockets` can
also be used in single-process servers if you want to create
your listening sockets in some way other than
def __init__(self, request_callback, no_keep_alive=False, io_loop=None,
xheaders=False, ssl_options=None, **kwargs):
self.request_callback = request_callback
self.no_keep_alive = no_keep_alive
self.xheaders = xheaders
TCPServer.__init__(self, io_loop=io_loop, ssl_options=ssl_options,
def handle_stream(self, stream, address):
HTTPConnection(stream, address, self.request_callback,
self.no_keep_alive, self.xheaders)
class _BadRequestException(Exception):
"""Exception class for malformed HTTP requests."""
class HTTPConnection(object):
"""Handles a connection to an HTTP client, executing HTTP requests.
We parse HTTP headers and bodies, and execute the request callback
until the HTTP conection is closed.
def __init__(self, stream, address, request_callback, no_keep_alive=False,
xheaders=False): = stream
if not in (socket.AF_INET, socket.AF_INET6):
# Unix (or other) socket; fake the remote address
address = ('', 0)
self.address = address
self.request_callback = request_callback
self.no_keep_alive = no_keep_alive
self.xheaders = xheaders
self._request = None
self._request_finished = False
# Save stack context here, outside of any request. This keeps
# contexts from one request from leaking into the next.
self._header_callback = stack_context.wrap(self._on_headers)"\r\n\r\n"), self._header_callback)
self._write_callback = None
def write(self, chunk, callback=None):
"""Writes a chunk of output to the stream."""
assert self._request, "Request closed"
if not
self._write_callback = stack_context.wrap(callback), self._on_write_complete)
def finish(self):
"""Finishes the request."""
assert self._request, "Request closed"
self._request_finished = True
if not
def _on_write_complete(self):
if self._write_callback is not None:
callback = self._write_callback
self._write_callback = None
# _on_write_complete is enqueued on the IOLoop whenever the
# IOStream's write buffer becomes empty, but it's possible for
# another callback that runs on the IOLoop before it to
# simultaneously write more data and finish the request. If
# there is still data in the IOStream, a future
# _on_write_complete will be responsible for calling
# _finish_request.
if self._request_finished and not
def _finish_request(self):
if self.no_keep_alive:
disconnect = True
connection_header = self._request.headers.get("Connection")
if connection_header is not None:
connection_header = connection_header.lower()
if self._request.supports_http_1_1():
disconnect = connection_header == "close"
elif ("Content-Length" in self._request.headers
or self._request.method in ("HEAD", "GET")):
disconnect = connection_header != "keep-alive"
disconnect = True
self._request = None
self._request_finished = False
if disconnect:
return"\r\n\r\n"), self._header_callback)
def _on_headers(self, data):
data = native_str(data.decode('latin1'))
eol = data.find("\r\n")
start_line = data[:eol]
method, uri, version = start_line.split(" ")
except ValueError:
raise _BadRequestException("Malformed HTTP request line")
if not version.startswith("HTTP/"):
raise _BadRequestException("Malformed HTTP version in HTTP Request-Line")
headers = httputil.HTTPHeaders.parse(data[eol:])
self._request = HTTPRequest(
connection=self, method=method, uri=uri, version=version,
headers=headers, remote_ip=self.address[0])
content_length = headers.get("Content-Length")
if content_length:
content_length = int(content_length)
if content_length >
raise _BadRequestException("Content-Length too long")
if headers.get("Expect") == "100-continue":"HTTP/1.1 100 (Continue)\r\n\r\n")), self._on_request_body)
except _BadRequestException, e:"Malformed HTTP request from %s: %s",
self.address[0], e)
def _on_request_body(self, data):
self._request.body = data
content_type = self._request.headers.get("Content-Type", "")
if self._request.method in ("POST", "PUT"):
if content_type.startswith("application/x-www-form-urlencoded"):
arguments = parse_qs_bytes(native_str(self._request.body))
for name, values in arguments.iteritems():
values = [v for v in values if v]
if values:
self._request.arguments.setdefault(name, []).extend(
elif content_type.startswith("multipart/form-data"):
fields = content_type.split(";")
for field in fields:
k, sep, v = field.strip().partition("=")
if k == "boundary" and v:
utf8(v), data,
logging.warning("Invalid multipart/form-data")
class HTTPRequest(object):
"""A single HTTP request.
All attributes are type `str` unless otherwise noted.
.. attribute:: method
HTTP request method, e.g. "GET" or "POST"
.. attribute:: uri
The requested uri.
.. attribute:: path
The path portion of `uri`
.. attribute:: query
The query portion of `uri`
.. attribute:: version
HTTP version specified in request, e.g. "HTTP/1.1"
.. attribute:: headers
`HTTPHeader` dictionary-like object for request headers. Acts like
a case-insensitive dictionary with additional methods for repeated
.. attribute:: body
Request body, if present, as a byte string.
.. attribute:: remote_ip
Client's IP address as a string. If `HTTPServer.xheaders` is set,
will pass along the real IP address provided by a load balancer
in the ``X-Real-Ip`` header
.. attribute:: protocol
The protocol used, either "http" or "https". If `HTTPServer.xheaders`
is set, will pass along the protocol used by a load balancer if
reported via an ``X-Scheme`` header.
.. attribute:: host
The requested hostname, usually taken from the ``Host`` header.
.. attribute:: arguments
GET/POST arguments are available in the arguments property, which
maps arguments names to lists of values (to support multiple values
for individual names). Names are of type `str`, while arguments
are byte strings. Note that this is different from
`RequestHandler.get_argument`, which returns argument values as
unicode strings.
.. attribute:: files
File uploads are available in the files property, which maps file
names to lists of :class:`HTTPFile`.
.. attribute:: connection
An HTTP request is attached to a single HTTP connection, which can
be accessed through the "connection" attribute. Since connections
are typically kept open in HTTP/1.1, multiple requests can be handled
sequentially on a single connection.
def __init__(self, method, uri, version="HTTP/1.0", headers=None,
body=None, remote_ip=None, protocol=None, host=None,
files=None, connection=None):
self.method = method
self.uri = uri
self.version = version
self.headers = headers or httputil.HTTPHeaders()
self.body = body or ""
if connection and connection.xheaders:
# Squid uses X-Forwarded-For, others use X-Real-Ip
self.remote_ip = self.headers.get(
"X-Real-Ip", self.headers.get("X-Forwarded-For", remote_ip))
if not self._valid_ip(self.remote_ip):
self.remote_ip = remote_ip
# AWS uses X-Forwarded-Proto
self.protocol = self.headers.get(
"X-Scheme", self.headers.get("X-Forwarded-Proto", protocol))
if self.protocol not in ("http", "https"):
self.protocol = "http"
self.remote_ip = remote_ip
if protocol:
self.protocol = protocol
elif connection and isinstance(,
self.protocol = "https"
self.protocol = "http" = host or self.headers.get("Host") or ""
self.files = files or {}
self.connection = connection
self._start_time = time.time()
self._finish_time = None
scheme, netloc, path, query, fragment = urlparse.urlsplit(native_str(uri))
self.path = path
self.query = query
arguments = parse_qs_bytes(query)
self.arguments = {}
for name, values in arguments.iteritems():
values = [v for v in values if v]
if values: self.arguments[name] = values
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 = {}
return self._cookies
def write(self, chunk, callback=None):
"""Writes the given chunk to the response stream."""
assert isinstance(chunk, bytes_type)
self.connection.write(chunk, callback=callback)
def finish(self):
"""Finishes this HTTP request on the open connection."""
self._finish_time = time.time()
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
def get_ssl_certificate(self):
"""Returns the client's SSL certificate, if any.
To use client certificates, the HTTPServer must have been constructed
with cert_reqs set in ssl_options, e.g.::
server = HTTPServer(app,
The return value is a dictionary, see SSLSocket.getpeercert() in
the standard library for more details.
except ssl.SSLError:
return None
def __repr__(self):
attrs = ("protocol", "host", "method", "uri", "version", "remote_ip",
args = ", ".join(["%s=%r" % (n, getattr(self, n)) for n in attrs])
return "%s(%s, headers=%s)" % (
self.__class__.__name__, args, dict(self.headers))
def _valid_ip(self, ip):
res = socket.getaddrinfo(ip, 0, socket.AF_UNSPEC,
return bool(res)
except socket.gaierror, e:
if e.args[0] == socket.EAI_NONAME:
return False
return True
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