[api] How do I get currency exchange rates via an API such as Google Finance?

I got this content from http://www.scriptarticle.com/2012/05/03/get-live-currency-rates-and-currency-conversion-using-php-and-apis/

<?php

function get_currency($from_Currency, $to_Currency, $amount) {
    $amount = urlencode($amount);
    $from_Currency = urlencode($from_Currency);
    $to_Currency = urlencode($to_Currency);

    $url = "http://www.google.com/finance/converter?a=$amount&from=$from_Currency&to=$to_Currency";

    $ch = curl_init();
    $timeout = 0;
    curl_setopt ($ch, CURLOPT_URL, $url);
    curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);

    curl_setopt ($ch, CURLOPT_USERAGENT,
                 "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)");
    curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
    $rawdata = curl_exec($ch);
    curl_close($ch);
    $data = explode('bld>', $rawdata);
    $data = explode($to_Currency, $data[1]);

    return round($data[0], 2);
}

// Call the function to get the currency converted
echo get_currency('USD', 'INR', 1);

?>