Mt.Gox coupon code redeeming script (redeem.py)

import sys
from urllib import urlencode
import urllib2
import time
from hashlib import sha512
from hmac import HMAC
import base64
import json

from mtgox_config import *

def get_nonce():
    return int(time.time()*100000)

def sign_data(secret, data):
    return base64.b64encode(str(HMAC(secret, data, sha512).digest()))

class requester:
    def __init__(self, auth_key, auth_secret):
        self.auth_key = auth_key
        self.auth_secret = base64.b64decode(auth_secret)

    def build_query(self, req={}):
        req["nonce"] = get_nonce()
        post_data = urlencode(req)
        headers = {}
        headers["User-Agent"] = "GoxApi"
        headers["Rest-Key"] = self.auth_key
        headers["Rest-Sign"] = sign_data(self.auth_secret, post_data)
        return (post_data, headers)

    def perform(self, path, args):
        data, headers = self.build_query(args)
        req = urllib2.Request("https://mtgox.com/api/0/"+path, data, headers)
        res = urllib2.urlopen(req, data)
        return json.load(res)

def redeem(code):
    r = requester(MTGOX_API_KEY, MTGOX_API_SECRET)
    return r.perform("redeemCode.php", {'code' : code})

if __name__=='__main__':
    if len(sys.argv) < 2:
        print "Usage: redeem.py <mtgox redeem code>"
    else:
        print redeem(sys.argv[1])