python stock price real time data feed (script debug)

i’m just beginning to learn to code and i want to apologize in advance if this question is trivial.

ive been trying to find a way to feed stock market data into python real time and came across this blog http://www.quantatrisk.com/2015/05/07/hacking-google-finance-in-pre-market-trading-python/

Below is the script i copied and pasted.

import urllib2  # works fine with Python 2.7.9 (not 3.4.+)
import json
import time

def fetchPreMarket(symbol, exchange):
    link = "http://finance.google.com/finance/info?client=ig&q="
    url = link+"%s:%s" % (exchange, symbol)
    u = urllib2.urlopen(url)
    content = u.read()
    data = json.loads(content[3:])
    info = data[0]
    t = str(info["elt"])    # time stamp
    l = float(info["l"])    # close price (previous trading day)
    p = float(info["el"])   # stock price in pre-market (after-hours)
    return (t,l,p)


p0 = 0
while True:
    t, l, p = fetchPreMarket("AAPL","NASDAQ")
    if(p!=p0):
        p0 = p
        print("%st%.2ft%.2ft%+.2ft%+.2f%%" % (t, l, p, p-l,
                                                 (p/l-1)*100.))
    time.sleep(60)

it seems to be a great code except when i run it, i get the following error message

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-11-012ec6dc7b0c> in <module>()
     18 p0 = 0
     19 while True:
---> 20     t, l, p = fetchPreMarket("AAPL","NASDAQ")
     21     if(p!=p0):
     22         p0 = p

<ipython-input-11-012ec6dc7b0c> in fetchPreMarket(symbol, exchange)
     10     data = json.loads(content[3:])
     11     info = data[0]
---> 12     t = str(info["elt"])    # time stamp
     13     l = float(info["l"])    # close price (previous trading day)
     14     p = float(info["el"])   # stock price in pre-market (after-hours)

KeyError: 'elt'

I tried modifying fetchPreMarket such that it just outputs info = data[0] but when i tried ‘print info’, nothing came of it.

Thanks in advance

Answer

So… The Google Finance API has been discontinued. I am surprised that link works, but there is no "etl" (or "el") key in the data.

And so, you’ll get KeyError: 'elt' at info["elt"]

For reference,

{
"id": "22144"
,"t" : "AAPL"
,"e" : "NASDAQ"
,"l" : "95.52"
,"l_fix" : "95.52"
,"l_cur" : "95.52"
,"s": "0"
,"ltt":"2:34PM EST"
,"lt" : "Feb 24, 2:34PM EST"
,"lt_dts" : "2016-02-24T14:34:54Z"
,"c" : "+0.83"
,"c_fix" : "0.83"
,"cp" : "0.88"
,"cp_fix" : "0.88"
,"ccol" : "chg"
,"pcls_fix" : "94.69"
}

You may have better luck with the googlefinance or yahoo-finance python modules rather than directly calling the API address.

It is worth noting that the Yahoo API is not “realtime”, though. It is about a 15 minute delayed quote.