Python Wrapper v1.2 Poloniex API, bugs fixed (2014 May 31st)

# Python Wrapper v1.2 Poloniex API, some bugs fixed (2014 May 31st)
#
# Original code copied from https://poloniex.com/api  http://pastebin.com/SB5c4Yr1 (unknown author)
# Some bugs repaired by me. Thank me if you want to - BTC 19ZLhMMyJMAExiLCx3H5fPv9DYDUFsK4Hk

import urllib
import urllib2
import json
import time
import hmac,hashlib

def createTimeStamp(datestr, stampformat="%Y-%m-%d %H:%M:%S"):
    return time.mktime(time.strptime(datestr, stampformat))

class poloniex:
    def __init__(self, APIKey, Secret):
        self.APIKey = APIKey
        self.Secret = Secret

    def post_process(self, before):
        after = before

        # Add timestamps if there isnt one but is a datetime
        if('return' in after):
            if(isinstance(after['return'], list)):
                for x in xrange(0, len(after['return'])):
                    if(isinstance(after['return'][x], dict)):
                        if('datetime' in after['return'][x] and 'timestamp' not in after['return'][x]):
                            after['return'][x]['timestamp'] = float(createTimeStamp(after['return'][x]['datetime']))

        return after

    def api_query(self, command, req={}):

        if(command == "returnTicker" or command == "return24Volume"):
            ret = urllib2.urlopen(urllib2.Request('https://poloniex.com/public?command=' + command))
            return json.loads(ret.read())
        elif(command == "returnOrderBook"):
            ret = urllib2.urlopen(urllib2.Request('http://poloniex.com/public?command=' + command + '&currencyPair=' + str(req['currencyPair'])))
            return json.loads(ret.read())
        elif(command == "returnMarketTradeHistory"):
            ret = urllib2.urlopen(urllib2.Request('http://poloniex.com/public?command=' + "returnTradeHistory" + '&currencyPair=' + str(req['currencyPair'])))
            return json.loads(ret.read())
        else:
            req['command'] = command
            req['nonce'] = int(time.time()*1000)
            post_data = urllib.urlencode(req)

            sign = hmac.new(self.Secret, post_data, hashlib.sha512).hexdigest()
            headers = {
                'Sign': sign,
                'Key': self.APIKey
            }

            ret = urllib2.urlopen(urllib2.Request('https://poloniex.com/tradingApi', post_data, headers))
            jsonRet = json.loads(ret.read())
            return self.post_process(jsonRet)


    def returnTicker(self):
        return self.api_query("returnTicker")

    def return24Volume(self):
        return self.api_query("return24Volume")

    def returnOrderBook (self, currencyPair):
        return self.api_query("returnOrderBook", {'currencyPair': currencyPair})

    def returnMarketTradeHistory (self, currencyPair):
        return self.api_query("returnMarketTradeHistory", {'currencyPair': currencyPair})


    # Returns all of your balances.
    # Outputs:
    # {"BTC":"0.59098578","LTC":"3.31117268", ... }
    def returnBalances(self):
        return self.api_query('returnBalances')


    # Returns all of your deposit addresses. Sample output:
    # {"BTC":"19YqztHmspv2egyD6jQM3yn81x5t5krVdJ","LTC":"LPgf9kjv9H1Vuh4XSaKhzBe8JHdou1WgUB", ... "ITC":"Press Generate.." ... }
    def returnDepositAddresses(self):
        return self.api_query('returnDepositAddresses')

    # Returns your deposit and withdrawal history within a range,
    # specified by the "start" and "end" POST parameters,
    # both of which should be given as UNIX timestamps. Sample output:
    # {"deposits":
    # [{"currency":"BTC","address":"...","amount":"0.01006132","confirmations":10,
    # "txid":"17f819a91369a9ff6c4a34216d434597cfc1b4a3d0489b46bd6f924137a47701","timestamp":1399305798,"status":"COMPLETE"},{"currency":"BTC","address":"...","amount":"0.00404104","confirmations":10,
    # "txid":"7acb90965b252e55a894b535ef0b0b65f45821f2899e4a379d3e43799604695c","timestamp":1399245916,"status":"COMPLETE"}],
    # "withdrawals":[{"withdrawalNumber":134933,"currency":"BTC","address":"1N2i5n8DwTGzUq2Vmn9TUL8J1vdr1XBDFg","amount":"5.00010000",
    # "timestamp":1399267904,"status":"COMPLETE: 36e483efa6aff9fd53a235177579d98451c4eb237c210e66cd2b9a2d4a988f8e","ipAddress":"..."}]}

    def returnDepositsWithdrawals(self, start, end):
        return self.api_query('returnDepositsWithdrawals',{"start":start, "end":end})

    # Returns your open orders for a given market, specified by the "currencyPair" POST parameter, e.g. "BTC_XCP"
    # Inputs:
    # currencyPair  The currency pair e.g. "BTC_XCP"
    # Outputs:
    # orderNumber   The order number
    # type          sell or buy
    # rate          Price the order is selling or buying at
    # Amount        Quantity of order
    # total         Total value of order (price * quantity)
    def returnOpenOrders(self,currencyPair):
        return self.api_query('returnOpenOrders',{"currencyPair":currencyPair})


    # Returns your trade history for a given market, specified by the "currencyPair" POST parameter
    # Inputs:
    # currencyPair  The currency pair e.g. "BTC_XCP"
    # Outputs:
    # date          Date in the form: "2014-02-19 03:44:59"
    # rate          Price the order is selling or buying at
    # amount        Quantity of order
    # total         Total value of order (price * quantity)
    # type          sell or buy
    def returnTradeHistory(self,currencyPair):
        return self.api_query('returnTradeHistory',{"currencyPair":currencyPair})

    # Places a buy order in a given market. Required POST parameters are "currencyPair", "rate", and "amount". If successful, the method will return the order number.
    # Inputs:
    # currencyPair  The curreny pair
    # rate          price the order is buying at
    # amount        Amount of coins to buy
    # Outputs:
    # orderNumber   The order number
    def buy(self,currencyPair,rate,amount):
        return self.api_query('buy',{"currencyPair":currencyPair,"rate":rate,"amount":amount})

    # Places a sell order in a given market. Required POST parameters are "currencyPair", "rate", and "amount". If successful, the method will return the order number.
    # Inputs:
    # currencyPair  The curreny pair
    # rate          price the order is selling at
    # amount        Amount of coins to sell
    # Outputs:
    # orderNumber   The order number
    def sell(self,currencyPair,rate,amount):
        return self.api_query('sell',{"currencyPair":currencyPair,"rate":rate,"amount":amount})

    # Cancels an order you have placed in a given market.
    # Required POST parameters are "currencyPair" and "orderNumber".
    # Inputs:
    # currencyPair  The curreny pair
    # orderNumber   The order number to cancel
    # Outputs:
    # succes        1 or 0
    def cancelOrder(self,currencyPair,orderNumber):
        return self.api_query('cancelOrder',{"currencyPair":currencyPair,"orderNumber":orderNumber})

    # Immediately places a withdrawal for a given currency, with no email confirmation.
    # In order to use this method, the withdrawal privilege must be enabled for your API key.
    # Required POST parameters are "currency", "amount", and "address".
    # Sample output: {"response":"Withdrew 2398 NXT."}
    # Inputs:
    # currency      The currency to withdraw
    # amount        The amount of this coin to withdraw
    # address       The withdrawal address
    # Outputs:
    # response      Text containing message about the withdrawal
    def withdraw(self, currency, amount, address):
        return self.api_query('withdraw',{"currency":currency, "amount":amount, "address":address})