# -*- coding: cp1252 -*-
# <PythonProxy.py>
#
#Copyright (c) <2009> <Fbio 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> <Fbio Domingues - fnds3000 in gmail.com> <MIT Licence>

 **************************************
 *** Python Proxy - A Fast HTTP proxy ***
 **************************************

Neste momento este proxy um Elie Proxy.

Suporta os mtodos HTTP:
 - OPTIONS;
 - GET;
 - HEAD;
 - POST;
 - PUT;
 - DELETE;
 - TRACE;
 - CONENCT.

Suporta:
 - Conex?es dos cliente em IPv4 ou IPv6;
 - Conex?es ao alvo em IPv4 e IPv6;
 - Conex?es todo o tipo de transmiss?o de dados TCP (CONNECT tunneling),
 p.e. liga??es SSL, como o caso do HTTPS.

A fazer:
 - Verificar se o input vindo do cliente est correcto;
 - Enviar os devidos HTTP erros se n?o, ou simplesmente quebrar a liga??o;
 - Criar um gestor de erros;
 - Criar ficheiro log de erros;
 - Colocar excep??es nos stios onde previsvel a ocorrncia de erros,
 p.e.sockets e ficheiros;
 - Rever tudo e melhorar a estrutura do programar e colocar nomes adequados nas
 variveis e mtodos;
 - Comentar o programa decentemente;
 - Doc Strings.

Funcionalidades futuras:
 - Adiconar a funcionalidade de proxy annimo e transparente;
 - Suportar FTP?.


(!) Aten??o o que se segue s tem efeito em conex?es n?o CONNECT, para estas o
 proxy sempre Elite.

Qual a diferen?a entre um proxy Elite, Annimo e Transparente?
 - Um proxy elite totalmente annimo, o servidor que o recebe n?o consegue ter
 conhecimento da existncia do proxy e n?o recebe o endere?o IP do cliente;
 - Quando usado um proxy annimo o servidor sabe que o cliente est a usar um
 proxy mas n?o sabe o endere?o IP do cliente;
 enviado o cabe?alho HTTP "Proxy-agent".
 - Um proxy transparente fornece ao servidor o IP do cliente e um informa??o que
 se est a usar um proxy.
 S?o enviados os cabe?alhos HTTP "Proxy-agent" e "HTTP_X_FORWARDED_FOR".

"""

import socket, thread, select

__version__ = '0.1.0 Draft 1'
BUFLEN = 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()
 self.client.close()
 self.target.close()

 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
 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 = ''
 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 = ''
 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
 #TODO:if error, use nslookup on proxy server
 try:
 (soc_family, _, _, _, address) = socket.getaddrinfo(host, port)[0]
 except:
 print "error when call sockt.getaddrinfo()"
 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
 while 1:
 count += 1
 (recv, _, error) = select.select(socs, [], socs, 3)
 if error:
 break
 if recv:
 for in_ in recv:
 data = in_.recv(BUFLEN)
 if in_ is self.client:
 out = self.target
 else:
 out = self.client
 if data:
 out.send(data)
 count = 0
 if count == time_out_max:
 break

def start_server(host='localhost', port=8080, IPv6=False, timeout=60,
 handler=ConnectionHandler):
 if IPv6==True:
 soc_type=socket.AF_INET6
 else:
 soc_type=socket.AF_INET
 soc = socket.socket(soc_type)
 soc.bind((host, port))
 print "Serving on %s:%d."%(host, port)#debug
 soc.listen(0)
 while 1:
 thread.start_new_thread(handler, soc.accept()+(timeout,))

if __name__ == '__main__':
 start_server()