529 lines
20 KiB
Python
529 lines
20 KiB
Python
#!/usr/bin/env python
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#
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# Copyright 2009 Facebook
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""A non-blocking, single-threaded HTTP server.
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Typical applications have little direct interaction with the `HTTPServer`
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class except to start a server at the beginning of the process
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(and even that is often done indirectly via `tornado.web.Application.listen`).
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This module also defines the `HTTPRequest` class which is exposed via
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`tornado.web.RequestHandler.request`.
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"""
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from __future__ import absolute_import, division, print_function, with_statement
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import socket
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import ssl
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import time
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from tornado.escape import native_str, parse_qs_bytes
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from tornado import httputil
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from tornado import iostream
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from tornado.log import gen_log
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from tornado import netutil
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from tornado.tcpserver import TCPServer
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from tornado import stack_context
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from tornado.util import bytes_type
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try:
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import Cookie # py2
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except ImportError:
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import http.cookies as Cookie # py3
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class HTTPServer(TCPServer):
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r"""A non-blocking, single-threaded HTTP server.
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A server is defined by a request callback that takes an HTTPRequest
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instance as an argument and writes a valid HTTP response with
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`HTTPRequest.write`. `HTTPRequest.finish` finishes the request (but does
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not necessarily close the connection in the case of HTTP/1.1 keep-alive
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requests). A simple example server that echoes back the URI you
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requested::
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import tornado.httpserver
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import tornado.ioloop
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def handle_request(request):
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message = "You requested %s\n" % request.uri
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request.write("HTTP/1.1 200 OK\r\nContent-Length: %d\r\n\r\n%s" % (
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len(message), message))
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request.finish()
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http_server = tornado.httpserver.HTTPServer(handle_request)
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http_server.listen(8888)
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tornado.ioloop.IOLoop.instance().start()
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`HTTPServer` is a very basic connection handler. It parses the request
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headers and body, but the request callback is responsible for producing
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the response exactly as it will appear on the wire. This affords
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maximum flexibility for applications to implement whatever parts
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of HTTP responses are required.
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`HTTPServer` supports keep-alive connections by default
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(automatically for HTTP/1.1, or for HTTP/1.0 when the client
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requests ``Connection: keep-alive``). This means that the request
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callback must generate a properly-framed response, using either
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the ``Content-Length`` header or ``Transfer-Encoding: chunked``.
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Applications that are unable to frame their responses properly
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should instead return a ``Connection: close`` header in each
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response and pass ``no_keep_alive=True`` to the `HTTPServer`
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constructor.
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If ``xheaders`` is ``True``, we support the
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``X-Real-Ip``/``X-Forwarded-For`` and
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``X-Scheme``/``X-Forwarded-Proto`` headers, which override the
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remote IP and URI scheme/protocol for all requests. These headers
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are useful when running Tornado behind a reverse proxy or load
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balancer. The ``protocol`` argument can also be set to ``https``
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if Tornado is run behind an SSL-decoding proxy that does not set one of
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the supported ``xheaders``.
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To make this server serve SSL traffic, send the ``ssl_options`` dictionary
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argument with the arguments required for the `ssl.wrap_socket` method,
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including ``certfile`` and ``keyfile``. (In Python 3.2+ you can pass
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an `ssl.SSLContext` object instead of a dict)::
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HTTPServer(applicaton, ssl_options={
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"certfile": os.path.join(data_dir, "mydomain.crt"),
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"keyfile": os.path.join(data_dir, "mydomain.key"),
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})
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`HTTPServer` initialization follows one of three patterns (the
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initialization methods are defined on `tornado.tcpserver.TCPServer`):
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1. `~tornado.tcpserver.TCPServer.listen`: simple single-process::
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server = HTTPServer(app)
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server.listen(8888)
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IOLoop.instance().start()
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In many cases, `tornado.web.Application.listen` can be used to avoid
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the need to explicitly create the `HTTPServer`.
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2. `~tornado.tcpserver.TCPServer.bind`/`~tornado.tcpserver.TCPServer.start`:
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simple multi-process::
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server = HTTPServer(app)
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server.bind(8888)
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server.start(0) # Forks multiple sub-processes
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IOLoop.instance().start()
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When using this interface, an `.IOLoop` must *not* be passed
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to the `HTTPServer` constructor. `~.TCPServer.start` will always start
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the server on the default singleton `.IOLoop`.
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3. `~tornado.tcpserver.TCPServer.add_sockets`: advanced multi-process::
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sockets = tornado.netutil.bind_sockets(8888)
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tornado.process.fork_processes(0)
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server = HTTPServer(app)
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server.add_sockets(sockets)
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IOLoop.instance().start()
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The `~.TCPServer.add_sockets` interface is more complicated,
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but it can be used with `tornado.process.fork_processes` to
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give you more flexibility in when the fork happens.
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`~.TCPServer.add_sockets` can also be used in single-process
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servers if you want to create your listening sockets in some
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way other than `tornado.netutil.bind_sockets`.
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"""
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def __init__(self, request_callback, no_keep_alive=False, io_loop=None,
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xheaders=False, ssl_options=None, protocol=None, **kwargs):
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self.request_callback = request_callback
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self.no_keep_alive = no_keep_alive
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self.xheaders = xheaders
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self.protocol = protocol
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TCPServer.__init__(self, io_loop=io_loop, ssl_options=ssl_options,
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**kwargs)
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def handle_stream(self, stream, address):
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HTTPConnection(stream, address, self.request_callback,
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self.no_keep_alive, self.xheaders, self.protocol)
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class _BadRequestException(Exception):
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"""Exception class for malformed HTTP requests."""
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pass
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class HTTPConnection(object):
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"""Handles a connection to an HTTP client, executing HTTP requests.
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We parse HTTP headers and bodies, and execute the request callback
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until the HTTP conection is closed.
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"""
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def __init__(self, stream, address, request_callback, no_keep_alive=False,
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xheaders=False, protocol=None):
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self.stream = stream
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self.address = address
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# Save the socket's address family now so we know how to
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# interpret self.address even after the stream is closed
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# and its socket attribute replaced with None.
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self.address_family = stream.socket.family
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self.request_callback = request_callback
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self.no_keep_alive = no_keep_alive
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self.xheaders = xheaders
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self.protocol = protocol
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self._clear_request_state()
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# Save stack context here, outside of any request. This keeps
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# contexts from one request from leaking into the next.
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self._header_callback = stack_context.wrap(self._on_headers)
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self.stream.set_close_callback(self._on_connection_close)
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self.stream.read_until(b"\r\n\r\n", self._header_callback)
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def _clear_request_state(self):
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"""Clears the per-request state.
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This is run in between requests to allow the previous handler
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to be garbage collected (and prevent spurious close callbacks),
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and when the connection is closed (to break up cycles and
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facilitate garbage collection in cpython).
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"""
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self._request = None
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self._request_finished = False
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self._write_callback = None
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self._close_callback = None
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def set_close_callback(self, callback):
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"""Sets a callback that will be run when the connection is closed.
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Use this instead of accessing
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`HTTPConnection.stream.set_close_callback
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<.BaseIOStream.set_close_callback>` directly (which was the
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recommended approach prior to Tornado 3.0).
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"""
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self._close_callback = stack_context.wrap(callback)
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def _on_connection_close(self):
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if self._close_callback is not None:
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callback = self._close_callback
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self._close_callback = None
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callback()
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# Delete any unfinished callbacks to break up reference cycles.
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self._header_callback = None
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self._clear_request_state()
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def close(self):
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self.stream.close()
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# Remove this reference to self, which would otherwise cause a
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# cycle and delay garbage collection of this connection.
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self._header_callback = None
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self._clear_request_state()
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def write(self, chunk, callback=None):
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"""Writes a chunk of output to the stream."""
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if not self.stream.closed():
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self._write_callback = stack_context.wrap(callback)
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self.stream.write(chunk, self._on_write_complete)
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def finish(self):
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"""Finishes the request."""
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self._request_finished = True
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# No more data is coming, so instruct TCP to send any remaining
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# data immediately instead of waiting for a full packet or ack.
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self.stream.set_nodelay(True)
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if not self.stream.writing():
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self._finish_request()
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def _on_write_complete(self):
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if self._write_callback is not None:
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callback = self._write_callback
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self._write_callback = None
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callback()
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# _on_write_complete is enqueued on the IOLoop whenever the
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# IOStream's write buffer becomes empty, but it's possible for
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# another callback that runs on the IOLoop before it to
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# simultaneously write more data and finish the request. If
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# there is still data in the IOStream, a future
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# _on_write_complete will be responsible for calling
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# _finish_request.
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if self._request_finished and not self.stream.writing():
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self._finish_request()
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def _finish_request(self):
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if self.no_keep_alive or self._request is None:
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disconnect = True
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else:
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connection_header = self._request.headers.get("Connection")
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if connection_header is not None:
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connection_header = connection_header.lower()
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if self._request.supports_http_1_1():
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disconnect = connection_header == "close"
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elif ("Content-Length" in self._request.headers
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or self._request.method in ("HEAD", "GET")):
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disconnect = connection_header != "keep-alive"
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else:
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disconnect = True
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self._clear_request_state()
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if disconnect:
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self.close()
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return
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try:
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# Use a try/except instead of checking stream.closed()
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# directly, because in some cases the stream doesn't discover
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# that it's closed until you try to read from it.
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self.stream.read_until(b"\r\n\r\n", self._header_callback)
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# Turn Nagle's algorithm back on, leaving the stream in its
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# default state for the next request.
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self.stream.set_nodelay(False)
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except iostream.StreamClosedError:
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self.close()
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def _on_headers(self, data):
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try:
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data = native_str(data.decode('latin1'))
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eol = data.find("\r\n")
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start_line = data[:eol]
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try:
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method, uri, version = start_line.split(" ")
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except ValueError:
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raise _BadRequestException("Malformed HTTP request line")
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if not version.startswith("HTTP/"):
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raise _BadRequestException("Malformed HTTP version in HTTP Request-Line")
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try:
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headers = httputil.HTTPHeaders.parse(data[eol:])
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except ValueError:
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# Probably from split() if there was no ':' in the line
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raise _BadRequestException("Malformed HTTP headers")
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# HTTPRequest wants an IP, not a full socket address
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if self.address_family in (socket.AF_INET, socket.AF_INET6):
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remote_ip = self.address[0]
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else:
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# Unix (or other) socket; fake the remote address
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remote_ip = '0.0.0.0'
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self._request = HTTPRequest(
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connection=self, method=method, uri=uri, version=version,
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headers=headers, remote_ip=remote_ip, protocol=self.protocol)
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content_length = headers.get("Content-Length")
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if content_length:
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content_length = int(content_length)
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if content_length > self.stream.max_buffer_size:
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raise _BadRequestException("Content-Length too long")
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if headers.get("Expect") == "100-continue":
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self.stream.write(b"HTTP/1.1 100 (Continue)\r\n\r\n")
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self.stream.read_bytes(content_length, self._on_request_body)
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return
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self.request_callback(self._request)
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except _BadRequestException as e:
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gen_log.info("Malformed HTTP request from %s: %s",
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self.address[0], e)
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self.close()
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return
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def _on_request_body(self, data):
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self._request.body = data
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if self._request.method in ("POST", "PATCH", "PUT"):
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httputil.parse_body_arguments(
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self._request.headers.get("Content-Type", ""), data,
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self._request.arguments, self._request.files)
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self.request_callback(self._request)
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class HTTPRequest(object):
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"""A single HTTP request.
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All attributes are type `str` unless otherwise noted.
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.. attribute:: method
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HTTP request method, e.g. "GET" or "POST"
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.. attribute:: uri
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The requested uri.
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.. attribute:: path
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The path portion of `uri`
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.. attribute:: query
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The query portion of `uri`
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.. attribute:: version
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HTTP version specified in request, e.g. "HTTP/1.1"
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.. attribute:: headers
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`.HTTPHeaders` dictionary-like object for request headers. Acts like
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a case-insensitive dictionary with additional methods for repeated
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headers.
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.. attribute:: body
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Request body, if present, as a byte string.
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.. attribute:: remote_ip
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Client's IP address as a string. If ``HTTPServer.xheaders`` is set,
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will pass along the real IP address provided by a load balancer
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in the ``X-Real-Ip`` or ``X-Forwarded-For`` header.
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.. versionchanged:: 3.1
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The list format of ``X-Forwarded-For`` is now supported.
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.. attribute:: protocol
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The protocol used, either "http" or "https". If ``HTTPServer.xheaders``
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is set, will pass along the protocol used by a load balancer if
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reported via an ``X-Scheme`` header.
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.. attribute:: host
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The requested hostname, usually taken from the ``Host`` header.
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.. attribute:: arguments
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GET/POST arguments are available in the arguments property, which
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maps arguments names to lists of values (to support multiple values
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for individual names). Names are of type `str`, while arguments
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are byte strings. Note that this is different from
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`.RequestHandler.get_argument`, which returns argument values as
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unicode strings.
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.. attribute:: files
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File uploads are available in the files property, which maps file
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names to lists of `.HTTPFile`.
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.. attribute:: connection
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An HTTP request is attached to a single HTTP connection, which can
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be accessed through the "connection" attribute. Since connections
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are typically kept open in HTTP/1.1, multiple requests can be handled
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sequentially on a single connection.
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"""
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def __init__(self, method, uri, version="HTTP/1.0", headers=None,
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body=None, remote_ip=None, protocol=None, host=None,
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files=None, connection=None):
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self.method = method
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self.uri = uri
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self.version = version
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self.headers = headers or httputil.HTTPHeaders()
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self.body = body or ""
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# set remote IP and protocol
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self.remote_ip = remote_ip
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if protocol:
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self.protocol = protocol
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elif connection and isinstance(connection.stream,
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iostream.SSLIOStream):
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self.protocol = "https"
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else:
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self.protocol = "http"
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# xheaders can override the defaults
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if connection and connection.xheaders:
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# Squid uses X-Forwarded-For, others use X-Real-Ip
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ip = self.headers.get("X-Forwarded-For", self.remote_ip)
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ip = ip.split(',')[-1].strip()
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ip = self.headers.get(
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"X-Real-Ip", ip)
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if netutil.is_valid_ip(ip):
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self.remote_ip = ip
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# AWS uses X-Forwarded-Proto
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proto = self.headers.get(
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"X-Scheme", self.headers.get("X-Forwarded-Proto", self.protocol))
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if proto in ("http", "https"):
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self.protocol = proto
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self.host = host or self.headers.get("Host") or "127.0.0.1"
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self.files = files or {}
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self.connection = connection
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self._start_time = time.time()
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self._finish_time = None
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self.path, sep, self.query = uri.partition('?')
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self.arguments = parse_qs_bytes(self.query, keep_blank_values=True)
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def supports_http_1_1(self):
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"""Returns True if this request supports HTTP/1.1 semantics"""
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return self.version == "HTTP/1.1"
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@property
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def cookies(self):
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"""A dictionary of Cookie.Morsel objects."""
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if not hasattr(self, "_cookies"):
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self._cookies = Cookie.SimpleCookie()
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if "Cookie" in self.headers:
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try:
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self._cookies.load(
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native_str(self.headers["Cookie"]))
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except Exception:
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self._cookies = {}
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return self._cookies
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def write(self, chunk, callback=None):
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"""Writes the given chunk to the response stream."""
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assert isinstance(chunk, bytes_type)
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self.connection.write(chunk, callback=callback)
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def finish(self):
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"""Finishes this HTTP request on the open connection."""
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self.connection.finish()
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self._finish_time = time.time()
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def full_url(self):
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"""Reconstructs the full URL for this request."""
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return self.protocol + "://" + self.host + self.uri
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def request_time(self):
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"""Returns the amount of time it took for this request to execute."""
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if self._finish_time is None:
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return time.time() - self._start_time
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else:
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return self._finish_time - self._start_time
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def get_ssl_certificate(self, binary_form=False):
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"""Returns the client's SSL certificate, if any.
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To use client certificates, the HTTPServer must have been constructed
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with cert_reqs set in ssl_options, e.g.::
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server = HTTPServer(app,
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ssl_options=dict(
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certfile="foo.crt",
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|
keyfile="foo.key",
|
|
cert_reqs=ssl.CERT_REQUIRED,
|
|
ca_certs="cacert.crt"))
|
|
|
|
By default, the return value is a dictionary (or None, if no
|
|
client certificate is present). If ``binary_form`` is true, a
|
|
DER-encoded form of the certificate is returned instead. See
|
|
SSLSocket.getpeercert() in the standard library for more
|
|
details.
|
|
http://docs.python.org/library/ssl.html#sslsocket-objects
|
|
"""
|
|
try:
|
|
return self.connection.stream.socket.getpeercert(
|
|
binary_form=binary_form)
|
|
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))
|