扭曲网络代理

1 投票
1 回答
3420 浏览
提问于 2025-04-16 02:17

我一直在运行这段代码(来自:http://blog.somethingaboutcode.com/?p=155):

from twisted.internet import reactor
from twisted.web import http
from twisted.web.proxy import Proxy, ProxyRequest, ProxyClientFactory, ProxyClient
from ImageFile import Parser
from StringIO import StringIO

class InterceptingProxyClient(ProxyClient):
    def __init__(self, *args, **kwargs):
        ProxyClient.__init__(self, *args, **kwargs)
        self.image_parser = None

    def handleHeader(self, key, value):
        if key == "Content-Type" and value in ["image/jpeg", "image/gif", "image/png"]:
            self.image_parser = Parser()
        if key == "Content-Length" and self.image_parser:
            pass
        else:
            ProxyClient.handleHeader(self, key, value)

    def handleEndHeaders(self):
        if self.image_parser:
            pass #Need to calculate and send Content-Length first
        else:
            ProxyClient.handleEndHeaders(self)

    def handleResponsePart(self, buffer):
        print buffer
        if self.image_parser:
            self.image_parser.feed(buffer)
        else:
            ProxyClient.handleResponsePart(self, buffer)

    def handleResponseEnd(self):
        if self.image_parser:
            image = self.image_parser.close()
            try:
                format = image.format
                image = image.rotate(180)
                s = StringIO()
                image.save(s, format)
                buffer = s.getvalue()
            except:
                buffer = ""
            ProxyClient.handleHeader(self, "Content-Length", len(buffer))
            ProxyClient.handleEndHeaders(self)
            ProxyClient.handleResponsePart(self, buffer)
        ProxyClient.handleResponseEnd(self)

class InterceptingProxyClientFactory(ProxyClientFactory):
    protocol = InterceptingProxyClient

class InterceptingProxyRequest(ProxyRequest):
    protocols = {'http': InterceptingProxyClientFactory}
    ports = {"http" : 80}

class InterceptingProxy(Proxy):
    requestFactory = InterceptingProxyRequest

factory = http.HTTPFactory()
factory.protocol = InterceptingProxy

reactor.listenTCP(8000, factory)
reactor.run()

每当我访问127.0.0.1:8000时,我会看到这个:

Traceback (most recent call last):
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\python\log.py",
line 84, in callWithLogger
    return callWithContext({"system": lp}, func, *args, **kw)
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\python\log.py",
line 69, in callWithContext
    return context.call({ILogContext: newCtx}, func, *args, **kw)
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\python\context.p
y", line 59, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\python\context.p
y", line 37, in callWithContext
    return func(*args,**kw)
--- <exception caught here> ---
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\internet\selectr
eactor.py", line 146, in _doReadOrWrite
    why = getattr(selectable, method)()
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\internet\tcp.py"
, line 460, in doRead
    return self.protocol.dataReceived(data)
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\protocols\basic.
py", line 251, in dataReceived
    why = self.lineReceived(line)
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\web\http.py", li
ne 1573, in lineReceived
    self.allContentReceived()
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\web\http.py", li
ne 1641, in allContentReceived
    req.requestReceived(command, path, version)
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\web\http.py", li
ne 807, in requestReceived
    self.process()
  File "C:\Program Files\Python 2.6.2\lib\site-packages\twisted\web\proxy.py", l
ine 147, in process
    port = self.ports[protocol]
exceptions.KeyError: ''

每次我设置火狐、谷歌浏览器或欧朋浏览器使用localhost:8000的代理时,都没有连接到代理(而且我也无法访问任何页面,这可能是因为没有连接到代理)。


好吧,它还是失败了,通过日志我发现,当我把火狐设置为使用localhost:8000的代理,并且没有直接在浏览器中访问代理(比如在火狐的地址栏输入localhost:8000)时,我得到了这个输出:

2010-08-04 12:31:18-0400 [-] Log opened.
2010-08-04 12:31:29-0400 [-] twisted.web.http.HTTPFactory starting on 8000
2010-08-04 12:31:29-0400 [-] Starting factory <twisted.web.http.HTTPFactory inst
ance at 0x010B3EE0>
2010-08-04 12:33:55-0400 [-] Received SIGINT, shutting down.
2010-08-04 12:33:55-0400 [twisted.web.http.HTTPFactory] (Port 8000 Closed)
2010-08-04 12:33:55-0400 [twisted.web.http.HTTPFactory] Stopping factory <twiste
d.web.http.HTTPFactory instance at 0x010B3EE0>
2010-08-04 12:33:55-0400 [-] Main loop terminated.

但是当我直接访问代理时,我会遇到关键错误。

另外,我无法进行流量监控;Wireshark似乎无法监控本地流量,而如果我使用Fiddler 2,它会自己设置为代理(这样我就不再使用我的代理服务器),然后就能工作(因为它使用的是Fiddler 2的代理)。

1 个回答

1

你看到的 KeyError 错误是因为连接代理时,发送的请求必须包含完整的网址,而不是简短的相对网址。如果你的浏览器不知道它在和代理通信,它会请求像 /foo/bar 这样的地址。如果它知道是在和代理通信,它就会请求类似 http://example.com/foo/bar 的完整地址。这里的 http://example.com/ 部分很重要,因为这是代理知道要去哪里获取数据的唯一方式。

至于为什么 Firefox、Chrome 和 Opera 在你配置它们连接代理后却无法连接,这就有点复杂了。确保你配置的是“HTTP 代理”,而不是其他类型的代理。一旦你确认了这一点,你可能需要使用像 Wireshark 这样的工具,来更好地查看网络层发生了什么。

有可能连接实际上是成功建立到代理的,但由于其他原因导致连接无法完成。在这种情况下,如果没有开启日志记录,你可能无法仅通过查看输出就知道代理是否收到了连接。要开启日志记录,可以尝试:

from sys import stdout
from twisted.python.log import startLogging
startLogging(stdout)

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