告诉urllib2使用自定义DNS [英] Tell urllib2 to use custom DNS

问题描述

我想告诉 urllib2.urlopen （或定制开启者）使用 127.0.0.1 （或 :: 1 ）来解析地址。我不会更改我的 /etc/resolv.conf 。

I'd like to tell urllib2.urlopen (or a custom opener) to use 127.0.0.1 (or ::1) to resolve addresses. I wouldn't change my /etc/resolv.conf, however.

一个可能的解决方案是使用工具像 dnspython 查询地址和 httplib 来构建一个自定义url开启器。我喜欢告诉 urlopen 来使用自定义名称服务器。任何建议？

One possible solution is to use a tool like dnspython to query addresses and httplib to build a custom url opener. I'd prefer telling urlopen to use a custom nameserver though. Any suggestions?

推荐答案

看起来像名称解析最终由 socket.create_connection 。

Looks like name resolution is ultimately handled by socket.create_connection.

-> urllib2.urlopen
-> httplib.HTTPConnection
-> socket.create_connection

虽然一旦设置了Host：头，您可以解析主机和传递IP地址到开启者。

Though once the "Host:" header has been set, you can resolve the host and pass on the IP address through down to the opener.

我建议您将 httplib.HTTPConnection 并将 connect 方法包含在之前修改 self.host ，然后再传递给 socket.create_connection 。

I'd suggest that you subclass httplib.HTTPConnection, and wrap the connect method to modify self.host before passing it to socket.create_connection.

然后子类 HTTPHandler （和 HTTPSHandler ）替换 http_open 方法，其中一个将 HTTPConnection 而不是httplib自己的方法传递给 do_open 。

Then subclass HTTPHandler (and HTTPSHandler) to replace the http_open method with one that passes your HTTPConnection instead of httplib's own to do_open.

像这样：

import urllib2
import httplib
import socket

def MyResolver(host):
  if host == 'news.bbc.co.uk':
    return '66.102.9.104' # Google IP
  else:
    return host

class MyHTTPConnection(httplib.HTTPConnection):
  def connect(self):
    self.sock = socket.create_connection((MyResolver(self.host),self.port),self.timeout)
class MyHTTPSConnection(httplib.HTTPSConnection):
  def connect(self):
    sock = socket.create_connection((MyResolver(self.host), self.port), self.timeout)
    self.sock = ssl.wrap_socket(sock, self.key_file, self.cert_file)

class MyHTTPHandler(urllib2.HTTPHandler):
  def http_open(self,req):
    return self.do_open(MyHTTPConnection,req)

class MyHTTPSHandler(urllib2.HTTPSHandler):
  def https_open(self,req):
    return self.do_open(MyHTTPSConnection,req)

opener = urllib2.build_opener(MyHTTPHandler,MyHTTPSHandler)
urllib2.install_opener(opener)

f = urllib2.urlopen('http://news.bbc.co.uk')
data = f.read()
from lxml import etree
doc = etree.HTML(data)

>>> print doc.xpath('//title/text()')
['Google']

如果您使用HTTPS，显然有证书问题，您需要填写MyResolver ...

Obviously there are certificate issues if you use the HTTPS, and you'll need to fill out MyResolver...

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