How to create a stock quote fetching app in python

I'm quite new to programming in Python.

I want to make an application which will fetch stock prices from google finance. One example is CSCO (Cisco Sytems). I would then use that data to warn the user when the stock reaches a certain value. It also needs to refresh every 30 seconds.

The problem is I dont have a clue how to fetch the data!

Anyone have any ideas?

Solution

This module comes courtesy of Corey Goldberg.

Program:

import urllib
import re

def get_quote(symbol):
    base_url = 'http://finance.google.com/finance?q='
    content = urllib.urlopen(base_url + symbol).read()
    m = re.search('id="ref_694653_l".*?>(.*?)<', content)
    if m:
        quote = m.group(1)
    else:
        quote = 'no quote available for: ' + symbol
    return quote

Sample Usage:

import stockquote
print stockquote.get_quote('goog')

Update: Changed the regular expression to match Google Finance's latest format (as of 23-Feb-2011). This demonstrates the main issue when relying upon screen scraping.