[python-win32] python sockets/proxy

Randy Syring rsyring at inteli-com.com
Thu Dec 16 20:46:51 CET 2010


Googling "http proxy python" turned up:

http://proxies.xhaus.com/python/

among other things.

--------------------------------------
Randy Syring
Intelicom
Direct: 502-276-0459
Office: 502-212-9913

For the wages of sin is death, but the
free gift of God is eternal life in
Christ Jesus our Lord (Rom 6:23)


On 12/16/2010 02:18 PM, RayS wrote:
> I was playing with some simple code I found for a proxy server, made 
> some mods to trap exceptions it had etc, but still have odd behavior; 
> one that (with Firefox at least) when the browser proxy is set to 
> 127.0.0.1:8080, DNS seems to be cached, or ?.
> I run the script locally and browse through it to a web site - mostly 
> OK. But sometimes going to a new site just brings up the home page of 
> the last site, ie, the base URL. I tried forcing gc, but no help 
> there. The script seems to take a request for a new URL and simple 
> return the host of the last URL.
>
> Also, craigslist.org fails entirely.
> Suggestions?
> Links to better proxy code to study?
>
> -Ray
>
>
>
> ==============================================
> # -*- coding: cp1252 -*-
> # <PythonProxy.py>
> #
> #Copyright (c) <2009> <Fábio Domingues - fnds3000 in gmail.com>
> #
> #Permission is hereby granted, free of charge, to any person
> #obtaining a copy of this software and associated documentation
> #files (the "Software"), to deal in the Software without
> #restriction, including without limitation the rights to use,
> #copy, modify, merge, publish, distribute, sublicense, and/or sell
> #copies of the Software, and to permit persons to whom the
> #Software is furnished to do so, subject to the following
> #conditions:
> #
> #The above copyright notice and this permission notice shall be
> #included in all copies or substantial portions of the Software.
> #
> #THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> #EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
> #OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
> #NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
> #HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
> #WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> #FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> #OTHER DEALINGS IN THE SOFTWARE.
>
> """\
> Copyright (c) <2009> <Fábio Domingues - fnds3000 in gmail.com> <MIT 
> Licence>
>
>                   **************************************
>                  *** Python Proxy - A Fast HTTP proxy ***
>                   **************************************
>
> Neste momento este proxy é um Elie Proxy.
>
> Suporta os métodos HTTP:
>  - OPTIONS;
>  - GET;
>  - HEAD;
>  - POST;
>  - PUT;
>  - DELETE;
>  - TRACE;
>  - CONENCT.
>
> Suporta:
>  - Conexões dos cliente em IPv4 ou IPv6;
>  - Conexões ao alvo em IPv4 e IPv6;
>  - Conexões todo o tipo de transmissão de dados TCP (CONNECT tunneling),
>      p.e. ligações SSL, como é o caso do HTTPS.
>
> A fazer:
>  - Verificar se o input vindo do cliente está correcto;
>    - Enviar os devidos HTTP erros se não, ou simplesmente quebrar a 
> ligação;
>  - Criar um gestor de erros;
>  - Criar ficheiro log de erros;
>  - Colocar excepções nos sítios onde é previsível a ocorrência de erros,
>      p.e.sockets e ficheiros;
>  - Rever tudo e melhorar a estrutura do programar e colocar nomes 
> adequados nas
>      variáveis e métodos;
>  - Comentar o programa decentemente;
>  - Doc Strings.
>
> Funcionalidades futuras:
>  - Adiconar a funcionalidade de proxy anónimo e transparente;
>  - Suportar FTP?.
>
>
> (!) Atenção o que se segue só tem efeito em conexões não CONNECT, para 
> estas o
>  proxy é sempre Elite.
>
> Qual a diferença entre um proxy Elite, Anónimo e Transparente?
>  - Um proxy elite é totalmente anónimo, o servidor que o recebe não 
> consegue ter
>      conhecimento da existência do proxy e não recebe o endereço IP do 
> cliente;
>  - Quando é usado um proxy anónimo o servidor sabe que o cliente está 
> a usar um
>      proxy mas não sabe o endereço IP do cliente;
>      É enviado o cabeçalho HTTP "Proxy-agent".
>  - Um proxy transparente fornece ao servidor o IP do cliente e um 
> informação que
>      se está a usar um proxy.
>      São enviados os cabeçalhos HTTP "Proxy-agent" e 
> "HTTP_X_FORWARDED_FOR".
>
> """
>
> import socket, thread, select, sys, gc
>
> __version__ = '0.1.0 Draft 1'
> BUFLEN = 4196 #8192
> VERSION = 'Python Proxy/'+__version__
> HTTPVER = 'HTTP/1.1'
>
> class ConnectionHandler:
>     def __init__(self, connection, address, timeout):
>         self.client = connection
>         self.client_buffer = ''
>         self.timeout = timeout
>         self.method, self.path, self.protocol = self.get_base_header()
>         if self.method=='CONNECT':
>             self.method_CONNECT()
>         elif self.method in ('OPTIONS', 'GET', 'HEAD', 'POST', 'PUT',
>                              'DELETE', 'TRACE'):
>             self.method_others()
>         #print '  closing client', self.client
>         self.client.close()
>         #print '  closing target', self.target
>         self.target.close()
>         #print '  closed'#, self.client, self.target
>
>     def get_base_header(self):
>         while 1:
>             self.client_buffer += self.client.recv(BUFLEN)
>             end = self.client_buffer.find('\n')
>             if end!=-1:
>                 break
>         #print '%s'%self.client_buffer[:end]#debug
>         print ' bs %s...'%self.client_buffer[:40]#debug
>         data = (self.client_buffer[:end+1]).split()
>         self.client_buffer = self.client_buffer[end+1:]
>         return data
>
>     def method_CONNECT(self):
>         self._connect_target(self.path)
>         self.client.send(HTTPVER+' 200 Connection established\n'+
>                          'Proxy-agent: %s\n\n'%VERSION)
>         self.client_buffer = ''
>         print "CONNECT", self.path[:35]
>         self._read_write()
>
>     def method_others(self):
>         self.path = self.path[7:]
>         i = self.path.find('/')
>         host = self.path[:i]
>         path = self.path[i:]
>         self._connect_target(host)
>         self.target.send('%s %s %s\n'%(self.method, path, self.protocol)+
>                          self.client_buffer)
>         self.client_buffer = ''
>         #print " M", self.method, host, 'pth:', self.path[:10]
>         self._read_write()
>
>     def _connect_target(self, host):
>         i = host.find(':')
>         if i!=-1:
>             port = int(host[i+1:])
>             host = host[:i]
>         else:
>             port = 80
>         (soc_family, _, _, _, address) = socket.getaddrinfo(host, port)[0]
>         self.target = socket.socket(soc_family)
>         self.target.connect(address)
>
>     def _read_write(self):
>         time_out_max = self.timeout#/3
>         socs = [self.client, self.target]
>         count = 0
>         data = ''
>         while 1:
>             count += 1
>             (recv, _, error) = select.select(socs, [], socs, 3)
>             if error:
>                 break
>             if recv:
>                 for in_ in recv:
>                     try:
>                         data = in_.recv(BUFLEN)
>                         #print "    OK:recv data:'%s'..., len:%d, 
> BUF:%d" % \
>                         #   (data[11:35], len(data), BUFLEN)
>                     except socket.error, (errno, strerror):
>                         if errno!=10053 and errno!=10054: ## 'Software 
> caused connection abort' or reset
>                             print "    recv error", (errno, strerror)
>                             print "      data:'%s'..., len:%d, BUF:%d" % \
>                                     (data[11:35], len(data), BUFLEN)
>                             pass
>                         else:
>                             break
>                     except:
>                         print ' ERR', sys.exc_info()[0]
>                     if in_ is self.client:
>                         out = self.target
>                     else:
>                         out = self.client
>                     if data:
>                         try:
>                             out.send(data)
>                         except socket.error, (errno, strerror):
>                             if errno!=10053 and errno!=10054: ## 
> 'Software caused connection abort' or reset
>                                 print "    send error", (errno, strerror)
>                                 print "      data:'%s'..., len:%d" % \
>                                         (data[:35], len(data))
>                                 pass
>                             else:
>                                 break
>                         except:
>                             print ' ERR', sys.exc_info()[0]
>                         count = 0
>             if count == time_out_max:
>                 break
>
> def start_server(host='localhost', port=8080, IPv6=False, timeout=10,
>                   handler=ConnectionHandler):
>     gc.enable()
>     if IPv6==True:
>         soc_type=socket.AF_INET6
>     else:
>         soc_type=socket.AF_INET
>     socket.setdefaulttimeout(3)
>     soc = socket.socket(soc_type)
>     soc.setblocking(1)
>     #print dir(soc)
>     soc.bind((host, port))
>     print "Serving on %s:%d."%(host, port)#debug
>     soc.listen(0)
>     while 1:
>         print 'new thread, collected', gc.collect(), gc.garbage
>         thread.start_new_thread(handler, soc.accept()+(timeout,))
>
> if __name__ == '__main__':
>     start_server()
>
>
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