Andrew Channels Dexter Pinion

Wherein I write some stuff that you may like to read. Or not, its up to you really.

July 19, 2004

Acquiring Stock Prices and Exchange Rates

Via a convoluted series of links I came across Ruby/Finance, an in progress port of Perl's Finance::Quote module. My immediate reaction was that this is a module which could usefully be ported to Python. I even entertained the thought of doing it myself, it would be an interesting exercise to learn a bit more about Perl and Ruby. But given my (lack of) progress on the other items on my to-do list it would never get done.

It wouldn't scratch my itch in the short term, either, as I already have perfectly serviceable Python functions to do these things for me. Unlike the Perl and Python code they don't go directly to Yahoo! Finance (the currency converter actually parses the HTML - yeuch) but rely on a SOAP service published by the nice people at www.xmethods.net (who do the scraping for us).

To get an exchange rate between currencies give this one a whirl;

def getFXRate(currencyFrom, currencyTo):
    "Get conversion rate between <currencyFrom> and <currencyTo>"
    rate = -1
    try:
        server = SOAP.SOAPProxy('http://services.xmethods.net/soap', \
                         namespace='urn:xmethods-CurrencyExchange')
        rate = server.getRate(currencyFrom, currencyTo)
    except:
        print "Exception getting rate between %s and %s" % ( currencyFrom, currencyTo )
    return rate

To get the latest price of a stock, try this function;

def getQuote(symbol):
    "Get latest price for <symbol>"
    price = -1
    try:
        server = SOAP.SOAPProxy('http://services.xmethods.net/soap', \
                        namespace='urn:xmethods-delayed-quotes')
        price = server.getQuote(symbol)
    except:
        print "Exception getting price for %s" % symbol
    return price

For the functions to work you will need the SOAP.py module from the Python Web Services project.

Posted by Andy Todd at July 19, 2004 09:48 PM

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