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#!/usr/bin/env python
from __future__ import absolute_import, division, print_function, with_statement
from tornado.escape import utf8, _unicode
from tornado import gen
from tornado.httpclient import HTTPResponse, HTTPError, AsyncHTTPClient, main, _RequestProxy
from tornado import httputil
from tornado.http1connection import HTTP1Connection, HTTP1ConnectionParameters
from tornado.iostream import StreamClosedError
from tornado.netutil import Resolver, OverrideResolver, _client_ssl_defaults
from tornado.log import gen_log
from tornado import stack_context
from tornado.tcpclient import TCPClient
from tornado.util import PY3
import base64
import collections
import copy
import functools
import re
import socket
import sys
from io import BytesIO
if PY3:
import urllib.parse as urlparse
else:
import urlparse
try:
import ssl
except ImportError:
# ssl is not available on Google App Engine.
ssl = None
try:
import certifi
except ImportError:
certifi = None
def _default_ca_certs():
if certifi is None:
raise Exception("The 'certifi' package is required to use https "
"in simple_httpclient")
return certifi.where()
class SimpleAsyncHTTPClient(AsyncHTTPClient):
"""Non-blocking HTTP client with no external dependencies.
This class implements an HTTP 1.1 client on top of Tornado's IOStreams.
Some features found in the curl-based AsyncHTTPClient are not yet
supported. In particular, proxies are not supported, connections
are not reused, and callers cannot select the network interface to be
used.
"""
def initialize(self, io_loop, max_clients=10,
hostname_mapping=None, max_buffer_size=104857600,
resolver=None, defaults=None, max_header_size=None,
max_body_size=None):
"""Creates a AsyncHTTPClient.
Only a single AsyncHTTPClient instance exists per IOLoop
in order to provide limitations on the number of pending connections.
``force_instance=True`` may be used to suppress this behavior.
Note that because of this implicit reuse, unless ``force_instance``
is used, only the first call to the constructor actually uses
its arguments. It is recommended to use the ``configure`` method
instead of the constructor to ensure that arguments take effect.
``max_clients`` is the number of concurrent requests that can be
in progress; when this limit is reached additional requests will be
queued. Note that time spent waiting in this queue still counts
against the ``request_timeout``.
``hostname_mapping`` is a dictionary mapping hostnames to IP addresses.
It can be used to make local DNS changes when modifying system-wide
settings like ``/etc/hosts`` is not possible or desirable (e.g. in
unittests).
``max_buffer_size`` (default 100MB) is the number of bytes
that can be read into memory at once. ``max_body_size``
(defaults to ``max_buffer_size``) is the largest response body
that the client will accept. Without a
``streaming_callback``, the smaller of these two limits
applies; with a ``streaming_callback`` only ``max_body_size``
does.
.. versionchanged:: 4.2
Added the ``max_body_size`` argument.
"""
super(SimpleAsyncHTTPClient, self).initialize(io_loop,
defaults=defaults)
self.max_clients = max_clients
self.queue = collections.deque()
self.active = {}
self.waiting = {}
self.max_buffer_size = max_buffer_size
self.max_header_size = max_header_size
self.max_body_size = max_body_size
# TCPClient could create a Resolver for us, but we have to do it
# ourselves to support hostname_mapping.
if resolver:
self.resolver = resolver
self.own_resolver = False
else:
self.resolver = Resolver(io_loop=io_loop)
self.own_resolver = True
if hostname_mapping is not None:
self.resolver = OverrideResolver(resolver=self.resolver,
mapping=hostname_mapping)
self.tcp_client = TCPClient(resolver=self.resolver, io_loop=io_loop)
def close(self):
super(SimpleAsyncHTTPClient, self).close()
if self.own_resolver:
self.resolver.close()
self.tcp_client.close()
def fetch_impl(self, request, callback):
key = object()
self.queue.append((key, request, callback))
if not len(self.active) < self.max_clients:
timeout_handle = self.io_loop.add_timeout(
self.io_loop.time() + min(request.connect_timeout,
request.request_timeout),
functools.partial(self._on_timeout, key, "in request queue"))
else:
timeout_handle = None
self.waiting[key] = (request, callback, timeout_handle)
self._process_queue()
if self.queue:
gen_log.debug("max_clients limit reached, request queued. "
"%d active, %d queued requests." % (
len(self.active), len(self.queue)))
def _process_queue(self):
with stack_context.NullContext():
while self.queue and len(self.active) < self.max_clients:
key, request, callback = self.queue.popleft()
if key not in self.waiting:
continue
self._remove_timeout(key)
self.active[key] = (request, callback)
release_callback = functools.partial(self._release_fetch, key)
self._handle_request(request, release_callback, callback)
def _connection_class(self):
return _HTTPConnection
def _handle_request(self, request, release_callback, final_callback):
self._connection_class()(
self.io_loop, self, request, release_callback,
final_callback, self.max_buffer_size, self.tcp_client,
self.max_header_size, self.max_body_size)
def _release_fetch(self, key):
del self.active[key]
self._process_queue()
def _remove_timeout(self, key):
if key in self.waiting:
request, callback, timeout_handle = self.waiting[key]
if timeout_handle is not None:
self.io_loop.remove_timeout(timeout_handle)
del self.waiting[key]
def _on_timeout(self, key, info=None):
"""Timeout callback of request.
Construct a timeout HTTPResponse when a timeout occurs.
:arg object key: A simple object to mark the request.
:info string key: More detailed timeout information.
"""
request, callback, timeout_handle = self.waiting[key]
self.queue.remove((key, request, callback))
error_message = "Timeout {0}".format(info) if info else "Timeout"
timeout_response = HTTPResponse(
request, 599, error=HTTPError(599, error_message),
request_time=self.io_loop.time() - request.start_time)
self.io_loop.add_callback(callback, timeout_response)
del self.waiting[key]
class _HTTPConnection(httputil.HTTPMessageDelegate):
_SUPPORTED_METHODS = set(["GET", "HEAD", "POST", "PUT", "DELETE", "PATCH", "OPTIONS"])
def __init__(self, io_loop, client, request, release_callback,
final_callback, max_buffer_size, tcp_client,
max_header_size, max_body_size):
self.start_time = io_loop.time()
self.io_loop = io_loop
self.client = client
self.request = request
self.release_callback = release_callback
self.final_callback = final_callback
self.max_buffer_size = max_buffer_size
self.tcp_client = tcp_client
self.max_header_size = max_header_size
self.max_body_size = max_body_size
self.code = None
self.headers = None
self.chunks = []
self._decompressor = None
# Timeout handle returned by IOLoop.add_timeout
self._timeout = None
self._sockaddr = None
with stack_context.ExceptionStackContext(self._handle_exception):
self.parsed = urlparse.urlsplit(_unicode(self.request.url))
if self.parsed.scheme not in ("http", "https"):
raise ValueError("Unsupported url scheme: %s" %
self.request.url)
# urlsplit results have hostname and port results, but they
# didn't support ipv6 literals until python 2.7.
netloc = self.parsed.netloc
if "@" in netloc:
userpass, _, netloc = netloc.rpartition("@")
host, port = httputil.split_host_and_port(netloc)
if port is None:
port = 443 if self.parsed.scheme == "https" else 80
if re.match(r'^\[.*\]$', host):
# raw ipv6 addresses in urls are enclosed in brackets
host = host[1:-1]
self.parsed_hostname = host # save final host for _on_connect
if request.allow_ipv6 is False:
af = socket.AF_INET
else:
af = socket.AF_UNSPEC
ssl_options = self._get_ssl_options(self.parsed.scheme)
timeout = min(self.request.connect_timeout, self.request.request_timeout)
if timeout:
self._timeout = self.io_loop.add_timeout(
self.start_time + timeout,
stack_context.wrap(functools.partial(self._on_timeout, "while connecting")))
self.tcp_client.connect(host, port, af=af,
ssl_options=ssl_options,
max_buffer_size=self.max_buffer_size,
callback=self._on_connect)
def _get_ssl_options(self, scheme):
if scheme == "https":
if self.request.ssl_options is not None:
return self.request.ssl_options
# If we are using the defaults, don't construct a
# new SSLContext.
if (self.request.validate_cert and
self.request.ca_certs is None and
self.request.client_cert is None and
self.request.client_key is None):
return _client_ssl_defaults
ssl_options = {}
if self.request.validate_cert:
ssl_options["cert_reqs"] = ssl.CERT_REQUIRED
if self.request.ca_certs is not None:
ssl_options["ca_certs"] = self.request.ca_certs
elif not hasattr(ssl, 'create_default_context'):
# When create_default_context is present,
# we can omit the "ca_certs" parameter entirely,
# which avoids the dependency on "certifi" for py34.
ssl_options["ca_certs"] = _default_ca_certs()
if self.request.client_key is not None:
ssl_options["keyfile"] = self.request.client_key
if self.request.client_cert is not None:
ssl_options["certfile"] = self.request.client_cert
# SSL interoperability is tricky. We want to disable
# SSLv2 for security reasons; it wasn't disabled by default
# until openssl 1.0. The best way to do this is to use
# the SSL_OP_NO_SSLv2, but that wasn't exposed to python
# until 3.2. Python 2.7 adds the ciphers argument, which
# can also be used to disable SSLv2. As a last resort
# on python 2.6, we set ssl_version to TLSv1. This is
# more narrow than we'd like since it also breaks
# compatibility with servers configured for SSLv3 only,
# but nearly all servers support both SSLv3 and TLSv1:
# http://blog.ivanristic.com/2011/09/ssl-survey-protocol-support.html
if sys.version_info >= (2, 7):
# In addition to disabling SSLv2, we also exclude certain
# classes of insecure ciphers.
ssl_options["ciphers"] = "DEFAULT:!SSLv2:!EXPORT:!DES"
else:
# This is really only necessary for pre-1.0 versions
# of openssl, but python 2.6 doesn't expose version
# information.
ssl_options["ssl_version"] = ssl.PROTOCOL_TLSv1
return ssl_options
return None
def _on_timeout(self, info=None):
"""Timeout callback of _HTTPConnection instance.
Raise a timeout HTTPError when a timeout occurs.
:info string key: More detailed timeout information.
"""
self._timeout = None
error_message = "Timeout {0}".format(info) if info else "Timeout"
if self.final_callback is not None:
raise HTTPError(599, error_message)
def _remove_timeout(self):
if self._timeout is not None:
self.io_loop.remove_timeout(self._timeout)
self._timeout = None
def _on_connect(self, stream):
if self.final_callback is None:
# final_callback is cleared if we've hit our timeout.
stream.close()
return
self.stream = stream
self.stream.set_close_callback(self.on_connection_close)
self._remove_timeout()
if self.final_callback is None:
return
if self.request.request_timeout:
self._timeout = self.io_loop.add_timeout(
self.start_time + self.request.request_timeout,
stack_context.wrap(functools.partial(self._on_timeout, "during request")))
if (self.request.method not in self._SUPPORTED_METHODS and
not self.request.allow_nonstandard_methods):
raise KeyError("unknown method %s" % self.request.method)
for key in ('network_interface',
'proxy_host', 'proxy_port',
'proxy_username', 'proxy_password',
'proxy_auth_mode'):
if getattr(self.request, key, None):
raise NotImplementedError('%s not supported' % key)
if "Connection" not in self.request.headers:
self.request.headers["Connection"] = "close"
if "Host" not in self.request.headers:
if '@' in self.parsed.netloc:
self.request.headers["Host"] = self.parsed.netloc.rpartition('@')[-1]
else:
self.request.headers["Host"] = self.parsed.netloc
username, password = None, None
if self.parsed.username is not None:
username, password = self.parsed.username, self.parsed.password
elif self.request.auth_username is not None:
username = self.request.auth_username
password = self.request.auth_password or ''
if username is not None:
if self.request.auth_mode not in (None, "basic"):
raise ValueError("unsupported auth_mode %s",
self.request.auth_mode)
auth = utf8(username) + b":" + utf8(password)
self.request.headers["Authorization"] = (b"Basic " +
base64.b64encode(auth))
if self.request.user_agent:
self.request.headers["User-Agent"] = self.request.user_agent
if not self.request.allow_nonstandard_methods:
# Some HTTP methods nearly always have bodies while others
# almost never do. Fail in this case unless the user has
# opted out of sanity checks with allow_nonstandard_methods.
body_expected = self.request.method in ("POST", "PATCH", "PUT")
body_present = (self.request.body is not None or
self.request.body_producer is not None)
if ((body_expected and not body_present) or
(body_present and not body_expected)):
raise ValueError(
'Body must %sbe None for method %s (unless '
'allow_nonstandard_methods is true)' %
('not ' if body_expected else '', self.request.method))
if self.request.expect_100_continue:
self.request.headers["Expect"] = "100-continue"
if self.request.body is not None:
# When body_producer is used the caller is responsible for
# setting Content-Length (or else chunked encoding will be used).
self.request.headers["Content-Length"] = str(len(
self.request.body))
if (self.request.method == "POST" and
"Content-Type" not in self.request.headers):
self.request.headers["Content-Type"] = "application/x-www-form-urlencoded"
if self.request.decompress_response:
self.request.headers["Accept-Encoding"] = "gzip"
req_path = ((self.parsed.path or '/') +
(('?' + self.parsed.query) if self.parsed.query else ''))
self.connection = self._create_connection(stream)
start_line = httputil.RequestStartLine(self.request.method,
req_path, '')
self.connection.write_headers(start_line, self.request.headers)
if self.request.expect_100_continue:
self._read_response()
else:
self._write_body(True)
def _create_connection(self, stream):
stream.set_nodelay(True)
connection = HTTP1Connection(
stream, True,
HTTP1ConnectionParameters(
no_keep_alive=True,
max_header_size=self.max_header_size,
max_body_size=self.max_body_size,
decompress=self.request.decompress_response),
self._sockaddr)
return connection
def _write_body(self, start_read):
if self.request.body is not None:
self.connection.write(self.request.body)
elif self.request.body_producer is not None:
fut = self.request.body_producer(self.connection.write)
if fut is not None:
fut = gen.convert_yielded(fut)
def on_body_written(fut):
fut.result()
self.connection.finish()
if start_read:
self._read_response()
self.io_loop.add_future(fut, on_body_written)
return
self.connection.finish()
if start_read:
self._read_response()
def _read_response(self):
# Ensure that any exception raised in read_response ends up in our
# stack context.
self.io_loop.add_future(
self.connection.read_response(self),
lambda f: f.result())
def _release(self):
if self.release_callback is not None:
release_callback = self.release_callback
self.release_callback = None
release_callback()
def _run_callback(self, response):
self._release()
if self.final_callback is not None:
final_callback = self.final_callback
self.final_callback = None
self.io_loop.add_callback(final_callback, response)
def _handle_exception(self, typ, value, tb):
if self.final_callback:
self._remove_timeout()
if isinstance(value, StreamClosedError):
if value.real_error is None:
value = HTTPError(599, "Stream closed")
else:
value = value.real_error
self._run_callback(HTTPResponse(self.request, 599, error=value,
request_time=self.io_loop.time() - self.start_time,
))
if hasattr(self, "stream"):
# TODO: this may cause a StreamClosedError to be raised
# by the connection's Future. Should we cancel the
# connection more gracefully?
self.stream.close()
return True
else:
# If our callback has already been called, we are probably
# catching an exception that is not caused by us but rather
# some child of our callback. Rather than drop it on the floor,
# pass it along, unless it's just the stream being closed.
return isinstance(value, StreamClosedError)
def on_connection_close(self):
if self.final_callback is not None:
message = "Connection closed"
if self.stream.error:
raise self.stream.error
try:
raise HTTPError(599, message)
except HTTPError:
self._handle_exception(*sys.exc_info())
def headers_received(self, first_line, headers):
if self.request.expect_100_continue and first_line.code == 100:
self._write_body(False)
return
self.code = first_line.code
self.reason = first_line.reason
self.headers = headers
if self._should_follow_redirect():
return
if self.request.header_callback is not None:
# Reassemble the start line.
self.request.header_callback('%s %s %s\r\n' % first_line)
for k, v in self.headers.get_all():
self.request.header_callback("%s: %s\r\n" % (k, v))
self.request.header_callback('\r\n')
def _should_follow_redirect(self):
return (self.request.follow_redirects and
self.request.max_redirects > 0 and
self.code in (301, 302, 303, 307))
def finish(self):
data = b''.join(self.chunks)
self._remove_timeout()
original_request = getattr(self.request, "original_request",
self.request)
if self._should_follow_redirect():
assert isinstance(self.request, _RequestProxy)
new_request = copy.copy(self.request.request)
new_request.url = urlparse.urljoin(self.request.url,
self.headers["Location"])
new_request.max_redirects = self.request.max_redirects - 1
del new_request.headers["Host"]
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.4
# Client SHOULD make a GET request after a 303.
# According to the spec, 302 should be followed by the same
# method as the original request, but in practice browsers
# treat 302 the same as 303, and many servers use 302 for
# compatibility with pre-HTTP/1.1 user agents which don't
# understand the 303 status.
if self.code in (302, 303):
new_request.method = "GET"
new_request.body = None
for h in ["Content-Length", "Content-Type",
"Content-Encoding", "Transfer-Encoding"]:
try:
del self.request.headers[h]
except KeyError:
pass
new_request.original_request = original_request
final_callback = self.final_callback
self.final_callback = None
self._release()
self.client.fetch(new_request, final_callback)
self._on_end_request()
return
if self.request.streaming_callback:
buffer = BytesIO()
else:
buffer = BytesIO(data) # TODO: don't require one big string?
response = HTTPResponse(original_request,
self.code, reason=getattr(self, 'reason', None),
headers=self.headers,
request_time=self.io_loop.time() - self.start_time,
buffer=buffer,
effective_url=self.request.url)
self._run_callback(response)
self._on_end_request()
def _on_end_request(self):
self.stream.close()
def data_received(self, chunk):
if self._should_follow_redirect():
# We're going to follow a redirect so just discard the body.
return
if self.request.streaming_callback is not None:
self.request.streaming_callback(chunk)
else:
self.chunks.append(chunk)
if __name__ == "__main__":
AsyncHTTPClient.configure(SimpleAsyncHTTPClient)
main()