Tiny HTTP Proxy in Python

28 November 2006
SUZUKI Hisao

I wrote a tiny HTTP proxy in Python in September, 2001.
It was for Python 2.1 on
BeOS R5 originally,
and has been working well ever since in every version of Python on
almost every platform, including Mac OS X and Windows 2000/XP.
I posted it to python-list on 17 June, 2003.
It had been available publicly as
http://mail.python.org/pipermail/python-list/2003-June/168957.html.

Now the page is gone and not found;
you cannot get the code conveniently.
So I write this page as its home.

TinyHTTPProxy-0.2.1.zip

MD5: f0bcffd54ce8e8fb286c23966d5b1ba6

To make the code open explicitly,
I put LICENSE.txt in the zip file.
It is based on
http://www.opensource.org/licenses/mit-license.html.
The text is as follows:

Copyright (c) 2001 SUZUKI Hisao

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.

The code of the proxy is as follows.
I hope it is short enough to be self-explanatory.
If your LAN is narrow or unstable, it would be better to increase
the default value of max_idling in _read_write()
from 20 to, say, 100.

The doc-string says that the CONNECT method has not been tested yet;
however, I can say now it has been tested and works well.

The first line of the code begins with #!/bin/sh.
The primary reason is that one of the targets is
BeOS R5
where there is no /usr/bin/env.

#!/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)

Copyright (c) 2001 SUZUKI Hisao

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.