from __future__ import annotations
import base64
from typing import TYPE_CHECKING, Dict, Optional, Tuple, Union
from urllib.parse import unquote, urlunparse
from urllib.request import ( # type: ignore[attr-defined]
_parse_proxy,
getproxies,
proxy_bypass,
)
from scrapy import Request, Spider
from scrapy.crawler import Crawler
from scrapy.exceptions import NotConfigured
from scrapy.http import Response
from scrapy.utils.httpobj import urlparse_cached
from scrapy.utils.python import to_bytes
if TYPE_CHECKING:
# typing.Self requires Python 3.11
from typing_extensions import Self
[docs]class HttpProxyMiddleware:
def __init__(self, auth_encoding: Optional[str] = "latin-1"):
self.auth_encoding: Optional[str] = auth_encoding
self.proxies: Dict[str, Tuple[Optional[bytes], str]] = {}
for type_, url in getproxies().items():
try:
self.proxies[type_] = self._get_proxy(url, type_)
# some values such as '/var/run/docker.sock' can't be parsed
# by _parse_proxy and as such should be skipped
except ValueError:
continue
@classmethod
def from_crawler(cls, crawler: Crawler) -> Self:
if not crawler.settings.getbool("HTTPPROXY_ENABLED"):
raise NotConfigured
auth_encoding: Optional[str] = crawler.settings.get("HTTPPROXY_AUTH_ENCODING")
return cls(auth_encoding)
def _basic_auth_header(self, username: str, password: str) -> bytes:
user_pass = to_bytes(
f"{unquote(username)}:{unquote(password)}", encoding=self.auth_encoding
)
return base64.b64encode(user_pass)
def _get_proxy(self, url: str, orig_type: str) -> Tuple[Optional[bytes], str]:
proxy_type, user, password, hostport = _parse_proxy(url)
proxy_url = urlunparse((proxy_type or orig_type, hostport, "", "", "", ""))
if user:
creds = self._basic_auth_header(user, password)
else:
creds = None
return creds, proxy_url
def process_request(
self, request: Request, spider: Spider
) -> Union[Request, Response, None]:
creds, proxy_url = None, None
if "proxy" in request.meta:
if request.meta["proxy"] is not None:
creds, proxy_url = self._get_proxy(request.meta["proxy"], "")
elif self.proxies:
parsed = urlparse_cached(request)
scheme = parsed.scheme
if (
# 'no_proxy' is only supported by http schemes
scheme not in ("http", "https")
or (parsed.hostname and not proxy_bypass(parsed.hostname))
) and scheme in self.proxies:
creds, proxy_url = self.proxies[scheme]
self._set_proxy_and_creds(request, proxy_url, creds)
return None
def _set_proxy_and_creds(
self, request: Request, proxy_url: Optional[str], creds: Optional[bytes]
) -> None:
if proxy_url:
request.meta["proxy"] = proxy_url
elif request.meta.get("proxy") is not None:
request.meta["proxy"] = None
if creds:
request.headers[b"Proxy-Authorization"] = b"Basic " + creds
request.meta["_auth_proxy"] = proxy_url
elif "_auth_proxy" in request.meta:
if proxy_url != request.meta["_auth_proxy"]:
if b"Proxy-Authorization" in request.headers:
del request.headers[b"Proxy-Authorization"]
del request.meta["_auth_proxy"]
elif b"Proxy-Authorization" in request.headers:
if proxy_url:
request.meta["_auth_proxy"] = proxy_url
else:
del request.headers[b"Proxy-Authorization"]