import base64
from urllib.parse import unquote, urlunparse
from urllib.request import getproxies, proxy_bypass, _parse_proxy
from scrapy.exceptions import NotConfigured
from scrapy.utils.httpobj import urlparse_cached
from scrapy.utils.python import to_bytes
[docs]class HttpProxyMiddleware(object):
def __init__(self, auth_encoding='latin-1'):
self.auth_encoding = auth_encoding
self.proxies = {}
for type_, url in getproxies().items():
self.proxies[type_] = self._get_proxy(url, type_)
@classmethod
def from_crawler(cls, crawler):
if not crawler.settings.getbool('HTTPPROXY_ENABLED'):
raise NotConfigured
auth_encoding = crawler.settings.get('HTTPPROXY_AUTH_ENCODING')
return cls(auth_encoding)
def _basic_auth_header(self, username, password):
user_pass = to_bytes(
'%s:%s' % (unquote(username), unquote(password)),
encoding=self.auth_encoding)
return base64.b64encode(user_pass)
def _get_proxy(self, url, orig_type):
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, spider):
# ignore if proxy is already set
if 'proxy' in request.meta:
if request.meta['proxy'] is None:
return
# extract credentials if present
creds, proxy_url = self._get_proxy(request.meta['proxy'], '')
request.meta['proxy'] = proxy_url
if creds and not request.headers.get('Proxy-Authorization'):
request.headers['Proxy-Authorization'] = b'Basic ' + creds
return
elif not self.proxies:
return
parsed = urlparse_cached(request)
scheme = parsed.scheme
# 'no_proxy' is only supported by http schemes
if scheme in ('http', 'https') and proxy_bypass(parsed.hostname):
return
if scheme in self.proxies:
self._set_proxy(request, scheme)
def _set_proxy(self, request, scheme):
creds, proxy = self.proxies[scheme]
request.meta['proxy'] = proxy
if creds:
request.headers['Proxy-Authorization'] = b'Basic ' + creds