miniMitM

import BaseHTTPServer, select, socket, SocketServer, urlparse

#Http server + threading mixin
class ThreadingHTTPServer (SocketServer.ThreadingMixIn, BaseHTTPServer.HTTPServer): pass

class HTTPProxy (BaseHTTPServer.BaseHTTPRequestHandler):
    rbufsize = 0  #Unbuffered file reader


    #Utility function to give a chance to modify self.headers before proxying
    def modifyOutboundHeaders(self):
        #Can add or modify outbound headers here, setting cookies or whatever
        return

    #Utility to modify output data before proxying
    def modifyOutboundData(self,data):
        return data

    #utility function to modify response data(headers and body)
    def modifyResponse(self, data):
        #Modify data as fit
        return data

    #Just a little function to handle output, didn't use it much but thought I might
    def trace(self, msg):
        print msg

    #Performs the actual proxy connection
    def connect(self, location, soc):
            #Parse connection information
            i = location.find(':')
            if i >= 0:
                host = location[:i]
                port = int(location[i+1:])
            else:
                host = location
                port = 80
            self.trace("Connecting to %s:%d" % (host,port))

            #Try to connect
            try:
                soc.connect((host,port))
            except socket.error, arg:
                try: msg = arg[1]
                except: msg = arg
                self.send_error(503, msg)
                return False
            return True

    #Reads data from either proxied connection or client and redirects it to the other
    def redirectData(self, soc, idleCount=50):
        loops = 0 #Tracks loops without reading; if we idle too long kill the connection
        while True:
            loops += 1
            (reads,_,errs) = select.select([self.connection, soc], [], [self.connection, soc])

            #Leave loop once we get an error as there is nothing left
            if errs: break

            #Read the data if anything and send it to the other source
            if reads:
                for i in reads:
                    data = i.recv(8192)
                    if data:
                        loops = 0
                        if i is soc:
                            data = self.modifyResponse(data)
                            self.connection.send(data)
                        else:
                            data = self.modifyOutboundData(data)
                            soc.send(data)
            if loops >= idleCount: break

    def do_CONNECT(self):
        soc = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            if self.connect(self.path, soc):
                #Successful connection
                self.trace("Connected.")
                self.wfile.write(self.protocol_version + " 200 Connection established\r\n")
                self.wfile.write("\r\n")
                self.redirectData(soc, 300)
        finally: soc.close()


    def do_GET(self):
        (proto, host, path, params, query, fragment) = urlparse.urlparse(self.path, 'http')
        if proto != 'http' or not host:
            self.send_error(500, "No support for HTTPS or no host provided.")
            return
        soc = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            if self.connect(host, soc):
                soc.send("%s %s %s\r\n" % (self.command,urlparse.urlunparse(('', '', path, params, query, '')),self.request_version))
                #Don't bother dealing with keep-alives
                self.headers['Connection'] = 'close'

                self.modifyOutboundHeaders()
                #Send the headers to socket
                for key_val in self.headers.items():
                    soc.send("%s: %s\r\n" % key_val)
                soc.send("\r\n")
                self.redirectData(soc)
        finally:
            soc.close()
            self.connection.close()

    #GET is generic enough that it handles everything
    do_POST   = do_GET
    do_HEAD   = do_GET
    do_PUT    = do_GET
    do_DELETE = do_GET

if __name__ == '__main__':
    #Run the server, default is port 8000 but argv[1] is read to determine port
    BaseHTTPServer.test(HTTPProxy, ThreadingHTTPServer)