#!/usr/bin/env python
#
# Copyright 2014 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# 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.
"""Client and server implementations of HTTP/1.x.
.. versionadded:: 4.0
"""
from __future__ import absolute_import, division, print_function, with_statement
import re
from tornado.concurrent import Future
from tornado.escape import native_str, utf8
from tornado import gen
from tornado import httputil
from tornado import iostream
from tornado.log import gen_log, app_log
from tornado import stack_context
from tornado.util import GzipDecompressor
class _QuietException(Exception):
def __init__(self):
pass
class _ExceptionLoggingContext(object):
"""Used with the ``with`` statement when calling delegate methods to
log any exceptions with the given logger. Any exceptions caught are
converted to _QuietException
"""
def __init__(self, logger):
self.logger = logger
def __enter__(self):
pass
def __exit__(self, typ, value, tb):
if value is not None:
self.logger.error("Uncaught exception", exc_info=(typ, value, tb))
raise _QuietException
class HTTP1ConnectionParameters(object):
"""Parameters for `.HTTP1Connection` and `.HTTP1ServerConnection`.
"""
def __init__(self, no_keep_alive=False, chunk_size=None,
max_header_size=None, header_timeout=None, max_body_size=None,
body_timeout=None, decompress=False):
"""
:arg bool no_keep_alive: If true, always close the connection after
one request.
:arg int chunk_size: how much data to read into memory at once
:arg int max_header_size: maximum amount of data for HTTP headers
:arg float header_timeout: how long to wait for all headers (seconds)
:arg int max_body_size: maximum amount of data for body
:arg float body_timeout: how long to wait while reading body (seconds)
:arg bool decompress: if true, decode incoming
``Content-Encoding: gzip``
"""
self.no_keep_alive = no_keep_alive
self.chunk_size = chunk_size or 65536
self.max_header_size = max_header_size or 65536
self.header_timeout = header_timeout
self.max_body_size = max_body_size
self.body_timeout = body_timeout
self.decompress = decompress
class HTTP1Connection(httputil.HTTPConnection):
"""Implements the HTTP/1.x protocol.
This class can be on its own for clients, or via `HTTP1ServerConnection`
for servers.
"""
def __init__(self, stream, is_client, params=None, context=None):
"""
:arg stream: an `.IOStream`
:arg bool is_client: client or server
:arg params: a `.HTTP1ConnectionParameters` instance or ``None``
:arg context: an opaque application-defined object that can be accessed
as ``connection.context``.
"""
self.is_client = is_client
self.stream = stream
if params is None:
params = HTTP1ConnectionParameters()
self.params = params
self.context = context
self.no_keep_alive = params.no_keep_alive
# The body limits can be altered by the delegate, so save them
# here instead of just referencing self.params later.
self._max_body_size = (self.params.max_body_size or
self.stream.max_buffer_size)
self._body_timeout = self.params.body_timeout
# _write_finished is set to True when finish() has been called,
# i.e. there will be no more data sent. Data may still be in the
# stream's write buffer.
self._write_finished = False
# True when we have read the entire incoming body.
self._read_finished = False
# _finish_future resolves when all data has been written and flushed
# to the IOStream.
self._finish_future = Future()
# If true, the connection should be closed after this request
# (after the response has been written in the server side,
# and after it has been read in the client)
self._disconnect_on_finish = False
self._clear_callbacks()
# Save the start lines after we read or write them; they
# affect later processing (e.g. 304 responses and HEAD methods
# have content-length but no bodies)
self._request_start_line = None
self._response_start_line = None
self._request_headers = None
# True if we are writing output with chunked encoding.
self._chunking_output = None
# While reading a body with a content-length, this is the
# amount left to read.
self._expected_content_remaining = None
# A Future for our outgoing writes, returned by IOStream.write.
self._pending_write = None
def read_response(self, delegate):
"""Read a single HTTP response.
Typical client-mode usage is to write a request using `write_headers`,
`write`, and `finish`, and then call ``read_response``.
:arg delegate: a `.HTTPMessageDelegate`
Returns a `.Future` that resolves to None after the full response has
been read.
"""
if self.params.decompress:
delegate = _GzipMessageDelegate(delegate, self.params.chunk_size)
return self._read_message(delegate)
@gen.coroutine
def _read_message(self, delegate):
need_delegate_close = False
try:
header_future = self.stream.read_until_regex(
b"\r?\n\r?\n",
max_bytes=self.params.max_header_size)
if self.params.header_timeout is None:
header_data = yield header_future
else:
try:
header_data = yield gen.with_timeout(
self.stream.io_loop.time() + self.params.header_timeout,
header_future,
io_loop=self.stream.io_loop,
quiet_exceptions=iostream.StreamClosedError)
except gen.TimeoutError:
self.close()
raise gen.Return(False)
start_line, headers = self._parse_headers(header_data)
if self.is_client:
start_line = httputil.parse_response_start_line(start_line)
self._response_start_line = start_line
else:
start_line = httputil.parse_request_start_line(start_line)
self._request_start_line = start_line
self._request_headers = headers
self._disconnect_on_finish = not self._can_keep_alive(
start_line, headers)
need_delegate_close = True
with _ExceptionLoggingContext(app_log):
header_future = delegate.headers_received(start_line, headers)
if header_future is not None:
yield header_future
if self.stream is None:
# We've been detached.
need_delegate_close = False
raise gen.Return(False)
skip_body = False
if self.is_client:
if (self._request_start_line is not None and
self._request_start_line.method == 'HEAD'):
skip_body = True
code = start_line.code
if code == 304:
# 304 responses may include the content-length header
# but do not actually have a body.
# http://tools.ietf.org/html/rfc7230#section-3.3
skip_body = True
if code >= 100 and code < 200:
# 1xx responses should never indicate the presence of
# a body.
if ('Content-Length' in headers or
'Transfer-Encoding' in headers):
raise httputil.HTTPInputError(
"Response code %d cannot have body" % code)
# TODO: client delegates will get headers_received twice
# in the case of a 100-continue. Document or change?
yield self._read_message(delegate)
else:
if (headers.get("Expect") == "100-continue" and
not self._write_finished):
self.stream.write(b"HTTP/1.1 100 (Continue)\r\n\r\n")
if not skip_body:
body_future = self._read_body(
start_line.code if self.is_client else 0, headers, delegate)
if body_future is not None:
if self._body_timeout is None:
yield body_future
else:
try:
yield gen.with_timeout(
self.stream.io_loop.time() + self._body_timeout,
body_future, self.stream.io_loop,
quiet_exceptions=iostream.StreamClosedError)
except gen.TimeoutError:
gen_log.info("Timeout reading body from %s",
self.context)
self.stream.close()
raise gen.Return(False)
self._read_finished = True
if not self._write_finished or self.is_client:
need_delegate_close = False
with _ExceptionLoggingContext(app_log):
delegate.finish()
# If we're waiting for the application to produce an asynchronous
# response, and we're not detached, register a close callback
# on the stream (we didn't need one while we were reading)
if (not self._finish_future.done() and
self.stream is not None and
not self.stream.closed()):
self.stream.set_close_callback(self._on_connection_close)
yield self._finish_future
if self.is_client and self._disconnect_on_finish:
self.close()
if self.stream is None:
raise gen.Return(False)
except httputil.HTTPInputError as e:
gen_log.info("Malformed HTTP message from %s: %s",
self.context, e)
self.close()
raise gen.Return(False)
finally:
if need_delegate_close:
with _ExceptionLoggingContext(app_log):
delegate.on_connection_close()
self._clear_callbacks()
raise gen.Return(True)
def _clear_callbacks(self):
"""Clears the callback attributes.
This allows the request handler to be garbage collected more
quickly in CPython by breaking up reference cycles.
"""
self._write_callback = None
self._write_future = None
self._close_callback = None
if self.stream is not None:
self.stream.set_close_callback(None)
def set_close_callback(self, callback):
"""Sets a callback that will be run when the connection is closed.
.. deprecated:: 4.0
Use `.HTTPMessageDelegate.on_connection_close` instead.
"""
self._close_callback = stack_context.wrap(callback)
def _on_connection_close(self):
# Note that this callback is only registered on the IOStream
# when we have finished reading the request and are waiting for
# the application to produce its response.
if self._close_callback is not None:
callback = self._close_callback
self._close_callback = None
callback()
if not self._finish_future.done():
self._finish_future.set_result(None)
self._clear_callbacks()
def close(self):
if self.stream is not None:
self.stream.close()
self._clear_callbacks()
if not self._finish_future.done():
self._finish_future.set_result(None)
def detach(self):
"""Take control of the underlying stream.
Returns the underlying `.IOStream` object and stops all further
HTTP processing. May only be called during
`.HTTPMessageDelegate.headers_received`. Intended for implementing
protocols like websockets that tunnel over an HTTP handshake.
"""
self._clear_callbacks()
stream = self.stream
self.stream = None
if not self._finish_future.done():
self._finish_future.set_result(None)
return stream
def set_body_timeout(self, timeout):
"""Sets the body timeout for a single request.
Overrides the value from `.HTTP1ConnectionParameters`.
"""
self._body_timeout = timeout
def set_max_body_size(self, max_body_size):
"""Sets the body size limit for a single request.
Overrides the value from `.HTTP1ConnectionParameters`.
"""
self._max_body_size = max_body_size
def write_headers(self, start_line, headers, chunk=None, callback=None):
"""Implements `.HTTPConnection.write_headers`."""
lines = []
if self.is_client:
self._request_start_line = start_line
lines.append(utf8('%s %s HTTP/1.1' % (start_line[0], start_line[1])))
# Client requests with a non-empty body must have either a
# Content-Length or a Transfer-Encoding.
self._chunking_output = (
start_line.method in ('POST', 'PUT', 'PATCH') and
'Content-Length' not in headers and
'Transfer-Encoding' not in headers)
else:
self._response_start_line = start_line
lines.append(utf8('HTTP/1.1 %s %s' % (start_line[1], start_line[2])))
self._chunking_output = (
# TODO: should this use
# self._request_start_line.version or
# start_line.version?
self._request_start_line.version == 'HTTP/1.1' and
# 304 responses have no body (not even a zero-length body), and so
# should not have either Content-Length or Transfer-Encoding.
# headers.
start_line.code != 304 and
# No need to chunk the output if a Content-Length is specified.
'Content-Length' not in headers and
# Applications are discouraged from touching Transfer-Encoding,
# but if they do, leave it alone.
'Transfer-Encoding' not in headers)
# If a 1.0 client asked for keep-alive, add the header.
if (self._request_start_line.version == 'HTTP/1.0' and
(self._request_headers.get('Connection', '').lower()
== 'keep-alive')):
headers['Connection'] = 'Keep-Alive'
if self._chunking_output:
headers['Transfer-Encoding'] = 'chunked'
if (not self.is_client and
(self._request_start_line.method == 'HEAD' or
start_line.code == 304)):
self._expected_content_remaining = 0
elif 'Content-Length' in headers:
self._expected_content_remaining = int(headers['Content-Length'])
else:
self._expected_content_remaining = None
lines.extend([utf8(n) + b": " + utf8(v) for n, v in headers.get_all()])
for line in lines:
if b'\n' in line:
raise ValueError('Newline in header: ' + repr(line))
future = None
if self.stream.closed():
future = self._write_future = Future()
future.set_exception(iostream.StreamClosedError())
future.exception()
else:
if callback is not None:
self._write_callback = stack_context.wrap(callback)
else:
future = self._write_future = Future()
data = b"\r\n".join(lines) + b"\r\n\r\n"
if chunk:
data += self._format_chunk(chunk)
self._pending_write = self.stream.write(data)
self._pending_write.add_done_callback(self._on_write_complete)
return future
def _format_chunk(self, chunk):
if self._expected_content_remaining is not None:
self._expected_content_remaining -= len(chunk)
if self._expected_content_remaining < 0:
# Close the stream now to stop further framing errors.
self.stream.close()
raise httputil.HTTPOutputError(
"Tried to write more data than Content-Length")
if self._chunking_output and chunk:
# Don't write out empty chunks because that means END-OF-STREAM
# with chunked encoding
return utf8("%x" % len(chunk)) + b"\r\n" + chunk + b"\r\n"
else:
return chunk
def write(self, chunk, callback=None):
"""Implements `.HTTPConnection.write`.
For backwards compatibility is is allowed but deprecated to
skip `write_headers` and instead call `write()` with a
pre-encoded header block.
"""
future = None
if self.stream.closed():
future = self._write_future = Future()
self._write_future.set_exception(iostream.StreamClosedError())
self._write_future.exception()
else:
if callback is not None:
self._write_callback = stack_context.wrap(callback)
else:
future = self._write_future = Future()
self._pending_write = self.stream.write(self._format_chunk(chunk))
self._pending_write.add_done_callback(self._on_write_complete)
return future
def finish(self):
"""Implements `.HTTPConnection.finish`."""
if (self._expected_content_remaining is not None and
self._expected_content_remaining != 0 and
not self.stream.closed()):
self.stream.close()
raise httputil.HTTPOutputError(
"Tried to write %d bytes less than Content-Length" %
self._expected_content_remaining)
if self._chunking_output:
if not self.stream.closed():
self._pending_write = self.stream.write(b"0\r\n\r\n")
self._pending_write.add_done_callback(self._on_write_complete)
self._write_finished = True
# If the app finished the request while we're still reading,
# divert any remaining data away from the delegate and
# close the connection when we're done sending our response.
# Closing the connection is the only way to avoid reading the
# whole input body.
if not self._read_finished:
self._disconnect_on_finish = True
# No more data is coming, so instruct TCP to send any remaining
# data immediately instead of waiting for a full packet or ack.
self.stream.set_nodelay(True)
if self._pending_write is None:
self._finish_request(None)
else:
self._pending_write.add_done_callback(self._finish_request)
def _on_write_complete(self, future):
exc = future.exception()
if exc is not None and not isinstance(exc, iostream.StreamClosedError):
future.result()
if self._write_callback is not None:
callback = self._write_callback
self._write_callback = None
self.stream.io_loop.add_callback(callback)
if self._write_future is not None:
future = self._write_future
self._write_future = None
future.set_result(None)
def _can_keep_alive(self, start_line, headers):
if self.params.no_keep_alive:
return False
connection_header = headers.get("Connection")
if connection_header is not None:
connection_header = connection_header.lower()
if start_line.version == "HTTP/1.1":
return connection_header != "close"
elif ("Content-Length" in headers
or headers.get("Transfer-Encoding", "").lower() == "chunked"
or start_line.method in ("HEAD", "GET")):
return connection_header == "keep-alive"
return False
def _finish_request(self, future):
self._clear_callbacks()
if not self.is_client and self._disconnect_on_finish:
self.close()
return
# Turn Nagle's algorithm back on, leaving the stream in its
# default state for the next request.
self.stream.set_nodelay(False)
if not self._finish_future.done():
self._finish_future.set_result(None)
def _parse_headers(self, data):
# The lstrip removes newlines that some implementations sometimes
# insert between messages of a reused connection. Per RFC 7230,
# we SHOULD ignore at least one empty line before the request.
# http://tools.ietf.org/html/rfc7230#section-3.5
data = native_str(data.decode('latin1')).lstrip("\r\n")
# RFC 7230 section allows for both CRLF and bare LF.
eol = data.find("\n")
start_line = data[:eol].rstrip("\r")
try:
headers = httputil.HTTPHeaders.parse(data[eol:])
except ValueError:
# probably form split() if there was no ':' in the line
raise httputil.HTTPInputError("Malformed HTTP headers: %r" %
data[eol:100])
return start_line, headers
def _read_body(self, code, headers, delegate):
if "Content-Length" in headers:
if "Transfer-Encoding" in headers:
# Response cannot contain both Content-Length and
# Transfer-Encoding headers.
# http://tools.ietf.org/html/rfc7230#section-3.3.3
raise httputil.HTTPInputError(
"Response with both Transfer-Encoding and Content-Length")
if "," in headers["Content-Length"]:
# Proxies sometimes cause Content-Length headers to get
# duplicated. If all the values are identical then we can
# use them but if they differ it's an error.
pieces = re.split(r',\s*', headers["Content-Length"])
if any(i != pieces[0] for i in pieces):
raise httputil.HTTPInputError(
"Multiple unequal Content-Lengths: %r" %
headers["Content-Length"])
headers["Content-Length"] = pieces[0]
content_length = int(headers["Content-Length"])
if content_length > self._max_body_size:
raise httputil.HTTPInputError("Content-Length too long")
else:
content_length = None
if code == 204:
# This response code is not allowed to have a non-empty body,
# and has an implicit length of zero instead of read-until-close.
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.3
if ("Transfer-Encoding" in headers or
content_length not in (None, 0)):
raise httputil.HTTPInputError(
"Response with code %d should not have body" % code)
content_length = 0
if content_length is not None:
return self._read_fixed_body(content_length, delegate)
if headers.get("Transfer-Encoding") == "chunked":
return self._read_chunked_body(delegate)
if self.is_client:
return self._read_body_until_close(delegate)
return None
@gen.coroutine
def _read_fixed_body(self, content_length, delegate):
while content_length > 0:
body = yield self.stream.read_bytes(
min(self.params.chunk_size, content_length), partial=True)
content_length -= len(body)
if not self._write_finished or self.is_client:
with _ExceptionLoggingContext(app_log):
ret = delegate.data_received(body)
if ret is not None:
yield ret
@gen.coroutine
def _read_chunked_body(self, delegate):
# TODO: "chunk extensions" http://tools.ietf.org/html/rfc2616#section-3.6.1
total_size = 0
while True:
chunk_len = yield self.stream.read_until(b"\r\n", max_bytes=64)
chunk_len = int(chunk_len.strip(), 16)
if chunk_len == 0:
return
total_size += chunk_len
if total_size > self._max_body_size:
raise httputil.HTTPInputError("chunked body too large")
bytes_to_read = chunk_len
while bytes_to_read:
chunk = yield self.stream.read_bytes(
min(bytes_to_read, self.params.chunk_size), partial=True)
bytes_to_read -= len(chunk)
if not self._write_finished or self.is_client:
with _ExceptionLoggingContext(app_log):
ret = delegate.data_received(chunk)
if ret is not None:
yield ret
# chunk ends with \r\n
crlf = yield self.stream.read_bytes(2)
assert crlf == b"\r\n"
@gen.coroutine
def _read_body_until_close(self, delegate):
body = yield self.stream.read_until_close()
if not self._write_finished or self.is_client:
with _ExceptionLoggingContext(app_log):
delegate.data_received(body)
class _GzipMessageDelegate(httputil.HTTPMessageDelegate):
"""Wraps an `HTTPMessageDelegate` to decode ``Content-Encoding: gzip``.
"""
def __init__(self, delegate, chunk_size):
self._delegate = delegate
self._chunk_size = chunk_size
self._decompressor = None
def headers_received(self, start_line, headers):
if headers.get("Content-Encoding") == "gzip":
self._decompressor = GzipDecompressor()
# Downstream delegates will only see uncompressed data,
# so rename the content-encoding header.
# (but note that curl_httpclient doesn't do this).
headers.add("X-Consumed-Content-Encoding",
headers["Content-Encoding"])
del headers["Content-Encoding"]
return self._delegate.headers_received(start_line, headers)
@gen.coroutine
def data_received(self, chunk):
if self._decompressor:
compressed_data = chunk
while compressed_data:
decompressed = self._decompressor.decompress(
compressed_data, self._chunk_size)
if decompressed:
ret = self._delegate.data_received(decompressed)
if ret is not None:
yield ret
compressed_data = self._decompressor.unconsumed_tail
else:
ret = self._delegate.data_received(chunk)
if ret is not None:
yield ret
def finish(self):
if self._decompressor is not None:
tail = self._decompressor.flush()
if tail:
# I believe the tail will always be empty (i.e.
# decompress will return all it can). The purpose
# of the flush call is to detect errors such
# as truncated input. But in case it ever returns
# anything, treat it as an extra chunk
self._delegate.data_received(tail)
return self._delegate.finish()
def on_connection_close(self):
return self._delegate.on_connection_close()
class HTTP1ServerConnection(object):
"""An HTTP/1.x server."""
def __init__(self, stream, params=None, context=None):
"""
:arg stream: an `.IOStream`
:arg params: a `.HTTP1ConnectionParameters` or None
:arg context: an opaque application-defined object that is accessible
as ``connection.context``
"""
self.stream = stream
if params is None:
params = HTTP1ConnectionParameters()
self.params = params
self.context = context
self._serving_future = None
@gen.coroutine
def close(self):
"""Closes the connection.
Returns a `.Future` that resolves after the serving loop has exited.
"""
self.stream.close()
# Block until the serving loop is done, but ignore any exceptions
# (start_serving is already responsible for logging them).
try:
yield self._serving_future
except Exception:
pass
def start_serving(self, delegate):
"""Starts serving requests on this connection.
:arg delegate: a `.HTTPServerConnectionDelegate`
"""
assert isinstance(delegate, httputil.HTTPServerConnectionDelegate)
self._serving_future = self._server_request_loop(delegate)
# Register the future on the IOLoop so its errors get logged.
self.stream.io_loop.add_future(self._serving_future,
lambda f: f.result())
@gen.coroutine
def _server_request_loop(self, delegate):
try:
while True:
conn = HTTP1Connection(self.stream, False,
self.params, self.context)
request_delegate = delegate.start_request(self, conn)
try:
ret = yield conn.read_response(request_delegate)
except (iostream.StreamClosedError,
iostream.UnsatisfiableReadError):
return
except _QuietException:
# This exception was already logged.
conn.close()
return
except Exception:
gen_log.error("Uncaught exception", exc_info=True)
conn.close()
return
if not ret:
return
yield gen.moment
finally:
delegate.on_close(self)
