Tuesday, December 16, 2008

HTTP Proxy Script in Python


The following is an HTTP proxy script written by Suzuki Hisao using the Python programming language. I lifted this post from the original posting at http://mail.python.org/pipermail/python-list/2003-June/210343.html since I may have need for this script in the future. I have tested this script and it works great. Its even better than the one I wrote using the Ruby programming language. Thanks Mr. Suzuki Hisao for sharing this with us.





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#!/bin/sh -
"exec" "python" "-O" "$0" "$@"

__doc__ = """Tiny HTTP Proxy.

This module implements GET, HEAD, POST, PUT and DELETE methods
on BaseHTTPServer, and behaves as an HTTP proxy. The CONNECT
method is also implemented experimentally, but has not been
tested yet.

Any help will be greatly appreciated. SUZUKI Hisao
"""

__version__ = "0.2.1"

import BaseHTTPServer, select, socket, SocketServer, urlparse

class ProxyHandler (BaseHTTPServer.BaseHTTPRequestHandler):
__base = BaseHTTPServer.BaseHTTPRequestHandler
__base_handle = __base.handle

server_version = "TinyHTTPProxy/" + __version__
rbufsize = 0 # self.rfile Be unbuffered

def handle(self):
(ip, port) = self.client_address
if hasattr(self, 'allowed_clients') and ip not in self.allowed_clients:
self.raw_requestline = self.rfile.readline()
if self.parse_request(): self.send_error(403)
else:
self.__base_handle()

def _connect_to(self, netloc, soc):
i = netloc.find(':')
if i >= 0:
host_port = netloc[:i], int(netloc[i+1:])
else:
host_port = netloc, 80
print "\t" "connect to %s:%d" % host_port
try: soc.connect(host_port)
except socket.error, arg:
try: msg = arg[1]
except: msg = arg
self.send_error(404, msg)
return 0
return 1

def do_CONNECT(self):
soc = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
if self._connect_to(self.path, soc):
self.log_request(200)
self.wfile.write(self.protocol_version +
" 200 Connection established\r\n")
self.wfile.write("Proxy-agent: %s\r\n" % self.version_string())
self.wfile.write("\r\n")
self._read_write(soc, 300)
finally:
print "\t" "bye"
soc.close()
self.connection.close()

def do_GET(self):
(scm, netloc, path, params, query, fragment) = urlparse.urlparse(
self.path, 'http')
if scm != 'http' or fragment or not netloc:
self.send_error(400, "bad url %s" % self.path)
return
soc = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
if self._connect_to(netloc, soc):
self.log_request()
soc.send("%s %s %s\r\n" % (
self.command,
urlparse.urlunparse(('', '', path, params, query, '')),
self.request_version))
self.headers['Connection'] = 'close'
del self.headers['Proxy-Connection']
for key_val in self.headers.items():
soc.send("%s: %s\r\n" % key_val)
soc.send("\r\n")
self._read_write(soc)
finally:
print "\t" "bye"
soc.close()
self.connection.close()

def _read_write(self, soc, max_idling=20):
iw = [self.connection, soc]
ow = []
count = 0
while 1:
count += 1
(ins, _, exs) = select.select(iw, ow, iw, 3)
if exs: break
if ins:
for i in ins:
if i is soc:
out = self.connection
else:
out = soc
data = i.recv(8192)
if data:
out.send(data)
count = 0
else:
print "\t" "idle", count
if count == max_idling: break

do_HEAD = do_GET
do_POST = do_GET
do_PUT = do_GET
do_DELETE=do_GET

class ThreadingHTTPServer (SocketServer.ThreadingMixIn,
BaseHTTPServer.HTTPServer): pass

if __name__ == '__main__':
from sys import argv
if argv[1:] and argv[1] in ('-h', '--help'):
print argv[0], "[port [allowed_client_name ...]]"
else:
if argv[2:]:
allowed = []
for name in argv[2:]:
client = socket.gethostbyname(name)
allowed.append(client)
print "Accept: %s (%s)" % (client, name)
ProxyHandler.allowed_clients = allowed
del argv[2:]
else:
print "Any clients will be served..."
BaseHTTPServer.test(ProxyHandler, ThreadingHTTPServer)
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