zulip/tools/python-proxy

#!/usr/bin/env python2.7
# -*- coding: cp1252 -*-
# <PythonProxy.py>
#
#Copyright (c) <2009> <F<>bio 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> <F<>bio Domingues - fnds3000 in gmail.com> <MIT Licence>

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

Neste momento este proxy <20> um Elie Proxy.

Suporta os m<>todos HTTP:
 - OPTIONS;
 - GET;
 - HEAD;
 - POST;
 - PUT;
 - DELETE;
 - TRACE;
 - CONENCT.

Suporta:
 - Conex<65>es dos cliente em IPv4 ou IPv6;
 - Conex<65>es ao alvo em IPv4 e IPv6;
 - Conex<65>es todo o tipo de transmiss<73>o de dados TCP (CONNECT tunneling),
     p.e. liga<67><61>es SSL, como <20> o caso do HTTPS.

A fazer:
 - Verificar se o input vindo do cliente est<73> correcto;
   - Enviar os devidos HTTP erros se n<>o, ou simplesmente quebrar a liga<67><61>o;
 - Criar um gestor de erros;
 - Criar ficheiro log de erros;
 - Colocar excep<65><70>es nos s<>tios onde <20> previs<69>vel a ocorr<72>ncia de erros,
     p.e.sockets e ficheiros;
 - Rever tudo e melhorar a estrutura do programar e colocar nomes adequados nas
     vari<72>veis e m<>todos;
 - Comentar o programa decentemente;
 - Doc Strings.

Funcionalidades futuras:
 - Adiconar a funcionalidade de proxy an<61>nimo e transparente;
 - Suportar FTP?.


(!) Aten<65><6E>o o que se segue s<> tem efeito em conex<65>es n<>o CONNECT, para estas o
 proxy <20> sempre Elite.

Qual a diferen<65>a entre um proxy Elite, An<41>nimo e Transparente?
 - Um proxy elite <20> totalmente an<61>nimo, o servidor que o recebe n<>o consegue ter
     conhecimento da exist<73>ncia do proxy e n<>o recebe o endere<72>o IP do cliente;
 - Quando <20> usado um proxy an<61>nimo o servidor sabe que o cliente est<73> a usar um
     proxy mas n<>o sabe o endere<72>o IP do cliente;
     <20> enviado o cabe<62>alho HTTP "Proxy-agent".
 - Um proxy transparente fornece ao servidor o IP do cliente e um informa<6D><61>o que
     se est<73> a usar um proxy.
     S<>o enviados os cabe<62>alhos HTTP "Proxy-agent" e "HTTP_X_FORWARDED_FOR".

"""
from __future__ import print_function
from __future__ import division

import socket, six.moves._thread, select
PORT = 8085

__version__ = '0.1.0 Draft 1'
BUFLEN = 8192
VERSION = 'Python Proxy/'+__version__
HTTPVER = 'HTTP/1.1'

class ConnectionHandler(object):
    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 True:
            self.client_buffer += self.client.recv(BUFLEN)
            end = self.client_buffer.find('\n')
            if end!=-1:
                break
        data = (self.client_buffer[:end+1]).split()
        self.client_buffer = self.client_buffer[end+1:]
        return data

    def method_CONNECT(self):
        print('self.path', self.path)
        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):
        print()
        print('=====================================')
        print('method', self.method)
        print('protocol', self.protocol)
        print('self.path', self.path)
        print()

        horking = False
        if horking:
            if self.path.endswith('.js'):
                print('HORKING JS!!!!!!!')
                print()
                return

            if self.path.endswith('.png'):
                print('HORKING PNG!!!!!!!')
                print()
                return

            if self.path.endswith('.css'):
                print('HORKING CSS!!!!!!!')
                print()
                return

        self._connect_target()
        payload = '%s %s %s\n' % (self.method, self.path, self.protocol)
        buf = payload
        try:
            headers, rest = self.client_buffer.split('\r\n\r\n')
        except:
            headers = self.client_buffer
            rest = None

        for line in headers.split('\n'):
            line = line.strip()
            if not line:
                continue
            print(repr(line))
            field, value = line.split(':', 1)
            if line.startswith('Host:'):
                line = line.replace(str(PORT), '9991')
            if field in ['Connection']:
                line = 'Connection: close'
            if field in ['If-Modified-Since']:
                continue
            buf += line + '\n'
        buf += '\n'
        buf = buf.replace('\n', '\r\n')
        self.target.send(buf)
        if rest:
            print('REST')
            print(repr(self.client_buffer))
            print(repr(buf))
            print(repr(rest))
            self.target.send(rest)

        self.client_buffer = ''
        self._read_write()

    def _connect_target(self):
        host = '127.0.0.1'
        port = 9991
        (soc_family, _, _, _, address) = socket.getaddrinfo(host, port)[0]
        self.target = socket.socket(soc_family)
        print('Connecting...', host, port)
        self.target.connect(address)
        print('Connected')

    def _read_write(self):
        time_out_max = self.timeout//3
        socs = [self.client, self.target]
        count = 0
        while True:
            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:
                        if data:
                            print()
                            print('OUT')
                            print('path =', self.path)
                            print(len(data))
                            print(repr(data))
                            print()
                        out = self.client
                        # super hacky and fragile
                        data = data.replace('9991', str(PORT))

                    if data:
                        if '400 Bad Request' in data:
                            print('DONE!')
                            import sys; sys.exit(1)
                        out.send(data)
                        count = 0
            if count == time_out_max:
                break

def start_server(host='localhost', port=PORT, 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.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    soc.bind((host, port))
    print("Serving on %s:%d." % (host, port)) #debug
    soc.listen(0)
    while True:
        six.moves._thread.start_new_thread(handler, soc.accept()+(timeout,))

if __name__ == '__main__':
    start_server()