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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