File: C:/Users/fred/anaconda3/Lib/site-packages/scrapy/core/downloader/handlers/http11.py
"""Download handlers for http and https schemes"""
import ipaddress
import logging
import re
from contextlib import suppress
from io import BytesIO
from time import time
from urllib.parse import urldefrag, urlunparse
from twisted.internet import defer, protocol, ssl
from twisted.internet.endpoints import TCP4ClientEndpoint
from twisted.internet.error import TimeoutError
from twisted.python.failure import Failure
from twisted.web.client import (
URI,
Agent,
HTTPConnectionPool,
ResponseDone,
ResponseFailed,
)
from twisted.web.http import PotentialDataLoss, _DataLoss
from twisted.web.http_headers import Headers as TxHeaders
from twisted.web.iweb import UNKNOWN_LENGTH, IBodyProducer
from zope.interface import implementer
from scrapy import signals
from scrapy.core.downloader.contextfactory import load_context_factory_from_settings
from scrapy.core.downloader.webclient import _parse
from scrapy.exceptions import StopDownload
from scrapy.http import Headers
from scrapy.responsetypes import responsetypes
from scrapy.utils.python import to_bytes, to_unicode
logger = logging.getLogger(__name__)
class HTTP11DownloadHandler:
lazy = False
def __init__(self, settings, crawler=None):
self._crawler = crawler
from twisted.internet import reactor
self._pool = HTTPConnectionPool(reactor, persistent=True)
self._pool.maxPersistentPerHost = settings.getint(
"CONCURRENT_REQUESTS_PER_DOMAIN"
)
self._pool._factory.noisy = False
self._contextFactory = load_context_factory_from_settings(settings, crawler)
self._default_maxsize = settings.getint("DOWNLOAD_MAXSIZE")
self._default_warnsize = settings.getint("DOWNLOAD_WARNSIZE")
self._fail_on_dataloss = settings.getbool("DOWNLOAD_FAIL_ON_DATALOSS")
self._disconnect_timeout = 1
@classmethod
def from_crawler(cls, crawler):
return cls(crawler.settings, crawler)
def download_request(self, request, spider):
"""Return a deferred for the HTTP download"""
agent = ScrapyAgent(
contextFactory=self._contextFactory,
pool=self._pool,
maxsize=getattr(spider, "download_maxsize", self._default_maxsize),
warnsize=getattr(spider, "download_warnsize", self._default_warnsize),
fail_on_dataloss=self._fail_on_dataloss,
crawler=self._crawler,
)
return agent.download_request(request)
def close(self):
from twisted.internet import reactor
d = self._pool.closeCachedConnections()
# closeCachedConnections will hang on network or server issues, so
# we'll manually timeout the deferred.
#
# Twisted issue addressing this problem can be found here:
# https://twistedmatrix.com/trac/ticket/7738.
#
# closeCachedConnections doesn't handle external errbacks, so we'll
# issue a callback after `_disconnect_timeout` seconds.
delayed_call = reactor.callLater(self._disconnect_timeout, d.callback, [])
def cancel_delayed_call(result):
if delayed_call.active():
delayed_call.cancel()
return result
d.addBoth(cancel_delayed_call)
return d
class TunnelError(Exception):
"""An HTTP CONNECT tunnel could not be established by the proxy."""
class TunnelingTCP4ClientEndpoint(TCP4ClientEndpoint):
"""An endpoint that tunnels through proxies to allow HTTPS downloads. To
accomplish that, this endpoint sends an HTTP CONNECT to the proxy.
The HTTP CONNECT is always sent when using this endpoint, I think this could
be improved as the CONNECT will be redundant if the connection associated
with this endpoint comes from the pool and a CONNECT has already been issued
for it.
"""
_truncatedLength = 1000
_responseAnswer = (
r"HTTP/1\.. (?P<status>\d{3})(?P<reason>.{," + str(_truncatedLength) + r"})"
)
_responseMatcher = re.compile(_responseAnswer.encode())
def __init__(
self,
reactor,
host,
port,
proxyConf,
contextFactory,
timeout=30,
bindAddress=None,
):
proxyHost, proxyPort, self._proxyAuthHeader = proxyConf
super().__init__(reactor, proxyHost, proxyPort, timeout, bindAddress)
self._tunnelReadyDeferred = defer.Deferred()
self._tunneledHost = host
self._tunneledPort = port
self._contextFactory = contextFactory
self._connectBuffer = bytearray()
def requestTunnel(self, protocol):
"""Asks the proxy to open a tunnel."""
tunnelReq = tunnel_request_data(
self._tunneledHost, self._tunneledPort, self._proxyAuthHeader
)
protocol.transport.write(tunnelReq)
self._protocolDataReceived = protocol.dataReceived
protocol.dataReceived = self.processProxyResponse
self._protocol = protocol
return protocol
def processProxyResponse(self, rcvd_bytes):
"""Processes the response from the proxy. If the tunnel is successfully
created, notifies the client that we are ready to send requests. If not
raises a TunnelError.
"""
self._connectBuffer += rcvd_bytes
# make sure that enough (all) bytes are consumed
# and that we've got all HTTP headers (ending with a blank line)
# from the proxy so that we don't send those bytes to the TLS layer
#
# see https://github.com/scrapy/scrapy/issues/2491
if b"\r\n\r\n" not in self._connectBuffer:
return
self._protocol.dataReceived = self._protocolDataReceived
respm = TunnelingTCP4ClientEndpoint._responseMatcher.match(self._connectBuffer)
if respm and int(respm.group("status")) == 200:
# set proper Server Name Indication extension
sslOptions = self._contextFactory.creatorForNetloc(
self._tunneledHost, self._tunneledPort
)
self._protocol.transport.startTLS(sslOptions, self._protocolFactory)
self._tunnelReadyDeferred.callback(self._protocol)
else:
if respm:
extra = {
"status": int(respm.group("status")),
"reason": respm.group("reason").strip(),
}
else:
extra = rcvd_bytes[: self._truncatedLength]
self._tunnelReadyDeferred.errback(
TunnelError(
"Could not open CONNECT tunnel with proxy "
f"{self._host}:{self._port} [{extra!r}]"
)
)
def connectFailed(self, reason):
"""Propagates the errback to the appropriate deferred."""
self._tunnelReadyDeferred.errback(reason)
def connect(self, protocolFactory):
self._protocolFactory = protocolFactory
connectDeferred = super().connect(protocolFactory)
connectDeferred.addCallback(self.requestTunnel)
connectDeferred.addErrback(self.connectFailed)
return self._tunnelReadyDeferred
def tunnel_request_data(host, port, proxy_auth_header=None):
r"""
Return binary content of a CONNECT request.
>>> from scrapy.utils.python import to_unicode as s
>>> s(tunnel_request_data("example.com", 8080))
'CONNECT example.com:8080 HTTP/1.1\r\nHost: example.com:8080\r\n\r\n'
>>> s(tunnel_request_data("example.com", 8080, b"123"))
'CONNECT example.com:8080 HTTP/1.1\r\nHost: example.com:8080\r\nProxy-Authorization: 123\r\n\r\n'
>>> s(tunnel_request_data(b"example.com", "8090"))
'CONNECT example.com:8090 HTTP/1.1\r\nHost: example.com:8090\r\n\r\n'
"""
host_value = to_bytes(host, encoding="ascii") + b":" + to_bytes(str(port))
tunnel_req = b"CONNECT " + host_value + b" HTTP/1.1\r\n"
tunnel_req += b"Host: " + host_value + b"\r\n"
if proxy_auth_header:
tunnel_req += b"Proxy-Authorization: " + proxy_auth_header + b"\r\n"
tunnel_req += b"\r\n"
return tunnel_req
class TunnelingAgent(Agent):
"""An agent that uses a L{TunnelingTCP4ClientEndpoint} to make HTTPS
downloads. It may look strange that we have chosen to subclass Agent and not
ProxyAgent but consider that after the tunnel is opened the proxy is
transparent to the client; thus the agent should behave like there is no
proxy involved.
"""
def __init__(
self,
reactor,
proxyConf,
contextFactory=None,
connectTimeout=None,
bindAddress=None,
pool=None,
):
super().__init__(reactor, contextFactory, connectTimeout, bindAddress, pool)
self._proxyConf = proxyConf
self._contextFactory = contextFactory
def _getEndpoint(self, uri):
return TunnelingTCP4ClientEndpoint(
reactor=self._reactor,
host=uri.host,
port=uri.port,
proxyConf=self._proxyConf,
contextFactory=self._contextFactory,
timeout=self._endpointFactory._connectTimeout,
bindAddress=self._endpointFactory._bindAddress,
)
def _requestWithEndpoint(
self, key, endpoint, method, parsedURI, headers, bodyProducer, requestPath
):
# proxy host and port are required for HTTP pool `key`
# otherwise, same remote host connection request could reuse
# a cached tunneled connection to a different proxy
key += self._proxyConf
return super()._requestWithEndpoint(
key=key,
endpoint=endpoint,
method=method,
parsedURI=parsedURI,
headers=headers,
bodyProducer=bodyProducer,
requestPath=requestPath,
)
class ScrapyProxyAgent(Agent):
def __init__(
self, reactor, proxyURI, connectTimeout=None, bindAddress=None, pool=None
):
super().__init__(
reactor=reactor,
connectTimeout=connectTimeout,
bindAddress=bindAddress,
pool=pool,
)
self._proxyURI = URI.fromBytes(proxyURI)
def request(self, method, uri, headers=None, bodyProducer=None):
"""
Issue a new request via the configured proxy.
"""
# Cache *all* connections under the same key, since we are only
# connecting to a single destination, the proxy:
return self._requestWithEndpoint(
key=("http-proxy", self._proxyURI.host, self._proxyURI.port),
endpoint=self._getEndpoint(self._proxyURI),
method=method,
parsedURI=URI.fromBytes(uri),
headers=headers,
bodyProducer=bodyProducer,
requestPath=uri,
)
class ScrapyAgent:
_Agent = Agent
_ProxyAgent = ScrapyProxyAgent
_TunnelingAgent = TunnelingAgent
def __init__(
self,
contextFactory=None,
connectTimeout=10,
bindAddress=None,
pool=None,
maxsize=0,
warnsize=0,
fail_on_dataloss=True,
crawler=None,
):
self._contextFactory = contextFactory
self._connectTimeout = connectTimeout
self._bindAddress = bindAddress
self._pool = pool
self._maxsize = maxsize
self._warnsize = warnsize
self._fail_on_dataloss = fail_on_dataloss
self._txresponse = None
self._crawler = crawler
def _get_agent(self, request, timeout):
from twisted.internet import reactor
bindaddress = request.meta.get("bindaddress") or self._bindAddress
proxy = request.meta.get("proxy")
if proxy:
proxyScheme, proxyNetloc, proxyHost, proxyPort, proxyParams = _parse(proxy)
scheme = _parse(request.url)[0]
proxyHost = to_unicode(proxyHost)
if scheme == b"https":
proxyAuth = request.headers.get(b"Proxy-Authorization", None)
proxyConf = (proxyHost, proxyPort, proxyAuth)
return self._TunnelingAgent(
reactor=reactor,
proxyConf=proxyConf,
contextFactory=self._contextFactory,
connectTimeout=timeout,
bindAddress=bindaddress,
pool=self._pool,
)
proxyScheme = proxyScheme or b"http"
proxyURI = urlunparse((proxyScheme, proxyNetloc, proxyParams, "", "", ""))
return self._ProxyAgent(
reactor=reactor,
proxyURI=to_bytes(proxyURI, encoding="ascii"),
connectTimeout=timeout,
bindAddress=bindaddress,
pool=self._pool,
)
return self._Agent(
reactor=reactor,
contextFactory=self._contextFactory,
connectTimeout=timeout,
bindAddress=bindaddress,
pool=self._pool,
)
def download_request(self, request):
from twisted.internet import reactor
timeout = request.meta.get("download_timeout") or self._connectTimeout
agent = self._get_agent(request, timeout)
# request details
url = urldefrag(request.url)[0]
method = to_bytes(request.method)
headers = TxHeaders(request.headers)
if isinstance(agent, self._TunnelingAgent):
headers.removeHeader(b"Proxy-Authorization")
if request.body:
bodyproducer = _RequestBodyProducer(request.body)
else:
bodyproducer = None
start_time = time()
d = agent.request(
method, to_bytes(url, encoding="ascii"), headers, bodyproducer
)
# set download latency
d.addCallback(self._cb_latency, request, start_time)
# response body is ready to be consumed
d.addCallback(self._cb_bodyready, request)
d.addCallback(self._cb_bodydone, request, url)
# check download timeout
self._timeout_cl = reactor.callLater(timeout, d.cancel)
d.addBoth(self._cb_timeout, request, url, timeout)
return d
def _cb_timeout(self, result, request, url, timeout):
if self._timeout_cl.active():
self._timeout_cl.cancel()
return result
# needed for HTTPS requests, otherwise _ResponseReader doesn't
# receive connectionLost()
if self._txresponse:
self._txresponse._transport.stopProducing()
raise TimeoutError(f"Getting {url} took longer than {timeout} seconds.")
def _cb_latency(self, result, request, start_time):
request.meta["download_latency"] = time() - start_time
return result
@staticmethod
def _headers_from_twisted_response(response):
headers = Headers()
if response.length != UNKNOWN_LENGTH:
headers[b"Content-Length"] = str(response.length).encode()
headers.update(response.headers.getAllRawHeaders())
return headers
def _cb_bodyready(self, txresponse, request):
headers_received_result = self._crawler.signals.send_catch_log(
signal=signals.headers_received,
headers=self._headers_from_twisted_response(txresponse),
body_length=txresponse.length,
request=request,
spider=self._crawler.spider,
)
for handler, result in headers_received_result:
if isinstance(result, Failure) and isinstance(result.value, StopDownload):
logger.debug(
"Download stopped for %(request)s from signal handler %(handler)s",
{"request": request, "handler": handler.__qualname__},
)
txresponse._transport.stopProducing()
txresponse._transport.loseConnection()
return {
"txresponse": txresponse,
"body": b"",
"flags": ["download_stopped"],
"certificate": None,
"ip_address": None,
"failure": result if result.value.fail else None,
}
# deliverBody hangs for responses without body
if txresponse.length == 0:
return {
"txresponse": txresponse,
"body": b"",
"flags": None,
"certificate": None,
"ip_address": None,
}
maxsize = request.meta.get("download_maxsize", self._maxsize)
warnsize = request.meta.get("download_warnsize", self._warnsize)
expected_size = txresponse.length if txresponse.length != UNKNOWN_LENGTH else -1
fail_on_dataloss = request.meta.get(
"download_fail_on_dataloss", self._fail_on_dataloss
)
if maxsize and expected_size > maxsize:
warning_msg = (
"Cancelling download of %(url)s: expected response "
"size (%(size)s) larger than download max size (%(maxsize)s)."
)
warning_args = {
"url": request.url,
"size": expected_size,
"maxsize": maxsize,
}
logger.warning(warning_msg, warning_args)
txresponse._transport.loseConnection()
raise defer.CancelledError(warning_msg % warning_args)
if warnsize and expected_size > warnsize:
logger.warning(
"Expected response size (%(size)s) larger than "
"download warn size (%(warnsize)s) in request %(request)s.",
{"size": expected_size, "warnsize": warnsize, "request": request},
)
def _cancel(_):
# Abort connection immediately.
txresponse._transport._producer.abortConnection()
d = defer.Deferred(_cancel)
txresponse.deliverBody(
_ResponseReader(
finished=d,
txresponse=txresponse,
request=request,
maxsize=maxsize,
warnsize=warnsize,
fail_on_dataloss=fail_on_dataloss,
crawler=self._crawler,
)
)
# save response for timeouts
self._txresponse = txresponse
return d
def _cb_bodydone(self, result, request, url):
headers = self._headers_from_twisted_response(result["txresponse"])
respcls = responsetypes.from_args(headers=headers, url=url, body=result["body"])
try:
version = result["txresponse"].version
protocol = f"{to_unicode(version[0])}/{version[1]}.{version[2]}"
except (AttributeError, TypeError, IndexError):
protocol = None
response = respcls(
url=url,
status=int(result["txresponse"].code),
headers=headers,
body=result["body"],
flags=result["flags"],
certificate=result["certificate"],
ip_address=result["ip_address"],
protocol=protocol,
)
if result.get("failure"):
result["failure"].value.response = response
return result["failure"]
return response
@implementer(IBodyProducer)
class _RequestBodyProducer:
def __init__(self, body):
self.body = body
self.length = len(body)
def startProducing(self, consumer):
consumer.write(self.body)
return defer.succeed(None)
def pauseProducing(self):
pass
def stopProducing(self):
pass
class _ResponseReader(protocol.Protocol):
def __init__(
self,
finished,
txresponse,
request,
maxsize,
warnsize,
fail_on_dataloss,
crawler,
):
self._finished = finished
self._txresponse = txresponse
self._request = request
self._bodybuf = BytesIO()
self._maxsize = maxsize
self._warnsize = warnsize
self._fail_on_dataloss = fail_on_dataloss
self._fail_on_dataloss_warned = False
self._reached_warnsize = False
self._bytes_received = 0
self._certificate = None
self._ip_address = None
self._crawler = crawler
def _finish_response(self, flags=None, failure=None):
self._finished.callback(
{
"txresponse": self._txresponse,
"body": self._bodybuf.getvalue(),
"flags": flags,
"certificate": self._certificate,
"ip_address": self._ip_address,
"failure": failure,
}
)
def connectionMade(self):
if self._certificate is None:
with suppress(AttributeError):
self._certificate = ssl.Certificate(
self.transport._producer.getPeerCertificate()
)
if self._ip_address is None:
self._ip_address = ipaddress.ip_address(
self.transport._producer.getPeer().host
)
def dataReceived(self, bodyBytes):
# This maybe called several times after cancel was called with buffered data.
if self._finished.called:
return
self._bodybuf.write(bodyBytes)
self._bytes_received += len(bodyBytes)
bytes_received_result = self._crawler.signals.send_catch_log(
signal=signals.bytes_received,
data=bodyBytes,
request=self._request,
spider=self._crawler.spider,
)
for handler, result in bytes_received_result:
if isinstance(result, Failure) and isinstance(result.value, StopDownload):
logger.debug(
"Download stopped for %(request)s from signal handler %(handler)s",
{"request": self._request, "handler": handler.__qualname__},
)
self.transport.stopProducing()
self.transport.loseConnection()
failure = result if result.value.fail else None
self._finish_response(flags=["download_stopped"], failure=failure)
if self._maxsize and self._bytes_received > self._maxsize:
logger.warning(
"Received (%(bytes)s) bytes larger than download "
"max size (%(maxsize)s) in request %(request)s.",
{
"bytes": self._bytes_received,
"maxsize": self._maxsize,
"request": self._request,
},
)
# Clear buffer earlier to avoid keeping data in memory for a long time.
self._bodybuf.truncate(0)
self._finished.cancel()
if (
self._warnsize
and self._bytes_received > self._warnsize
and not self._reached_warnsize
):
self._reached_warnsize = True
logger.warning(
"Received more bytes than download "
"warn size (%(warnsize)s) in request %(request)s.",
{"warnsize": self._warnsize, "request": self._request},
)
def connectionLost(self, reason):
if self._finished.called:
return
if reason.check(ResponseDone):
self._finish_response()
return
if reason.check(PotentialDataLoss):
self._finish_response(flags=["partial"])
return
if reason.check(ResponseFailed) and any(
r.check(_DataLoss) for r in reason.value.reasons
):
if not self._fail_on_dataloss:
self._finish_response(flags=["dataloss"])
return
if not self._fail_on_dataloss_warned:
logger.warning(
"Got data loss in %s. If you want to process broken "
"responses set the setting DOWNLOAD_FAIL_ON_DATALOSS = False"
" -- This message won't be shown in further requests",
self._txresponse.request.absoluteURI.decode(),
)
self._fail_on_dataloss_warned = True
self._finished.errback(reason)