gistfile1.py

#! /usr/bin/python
import sys
import signal
from json import dumps, loads
from platform import platform
from urlparse import urlparse
from socket import gethostbyaddr
from SocketServer import TCPServer, ForkingTCPServer
from SimpleHTTPServer import SimpleHTTPRequestHandler

#need to run as root for ports lower than 1024, usually
PORT = 8000

try:
    PRE_LOOKUP = loads(open('cached_lookup', 'r').read())
except:
    PRE_LOOKUP = {}

SE_KEYWORDS = ['google', 'yahoo', 'msn', 'bing']

class Host():
    def __init__(self, ip):
        self.ip = ip
        self.name = gethostbyaddr(ip)[0]

class Handler(SimpleHTTPRequestHandler):
    def do_GET(self):
        try:
            # index 4 is always querystring
            query_string = urlparse(self.path)[4]
            # we don't care what it's called, just the first value passed
            ip = query_string.split('=')[1]
            try:
                hostname = PRE_LOOKUP[ip].name
            except KeyError:
                hn = Host(ip)
                PRE_LOOKUP[ip] = hn
            hostname = hn.name
            print str(PRE_LOOKUP)
            self.wfile.write(hostname)
        except:
            pass

def signal_handler(signal, frame):
    fp = open('cached_lookup', 'w+')
    fp.write(dumps(PRE_LOOKUP))
    fp.close()
    sys.exit(0)

if __name__ == '__main__':
    signal.signal(signal.SIGINT, signal_handler)
    if len(sys.argv) > 1:
        PORT = int(sys.argv[1])
    # Windows doesn't support process forking
    if 'Windows' in platform():
        httpd = TCPServer(("", PORT), Handler)
    else:
        httpd = ForkingTCPServer(("", PORT), Handler)
    print "Serving HTTP at port: %i" % PORT
    httpd.serve_forever()