In a bid to find a more reliable source for currency exchange rates and faster servers to boot, I’ve created this Module to get rates from Yahoo! Finance. Note that this may be subject to Yahoo! T’s & C’s so you better read them before using this.

I’ve made this upgrade-proof to the best of my knowledge; it uses local xml and Module code. But of course, do take back-ups and test your back-ups. This is supplied as is and is not implied to work at all. You know the drill.

Please Note This is not available on Magento Connect. Installation consists of just one new file and one local file edit. Command line with vim or any FTP enabled text editor will do the trick nicely.
Step 1 – Create Folders & File Structure

I have mimicked the Webservicex currency retrieval code. That one resides in /app/code/core/Mage/Directory/Model/Currency/Import/Webservicex.php so you can have a look yourself. In line with that code and structure, first create the following folder structure and file:

[code]/app/code/local/JT/Directory/Model/Currency/Import/Yahoofinance.php[/code]

Step 2 – Paste Code into Yahoofinance.php

[code]<?php
/**
* JT
*
* NOTICE OF LICENSE
*
* This source file is subject to the Open Software License (OSL 3.0)
* that is bundled with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://opensource.org/licenses/osl-3.0.php
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@magentocommerce.com so we can send you a copy immediately.
*
* @category   JT
* @package    JT_Directory
* @copyright  Copyright (c) 2009 JT
* @license    http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
*
* All credits to Magento Core Development Team who’s Webservicex code I liberally borrowed
* as well as Mark Alexander Bain’s idea and code as displayed on the following url, accessed Feb 16th 2009
* http://ajax-programming.suite101.com/article.cfm/currency_conversion_with_yahoo_finance
*/
/**
* Currency rate import model (From quote.yahoo.com)
*
* @category   JT
* @package    JT_Directory
* @author      Magento Enthusiast <J.T.>
*/
class JT_Directory_Model_Currency_Import_Yahoofinance extends Mage_Directory_Model_Currency_Import_Abstract
{
protected $_url = ‘http://quote.yahoo.com/d/quotes.csv?s={{CURRENCY_FROM}}{{CURRENCY_TO}}=X&f=l1&e=.csv’;
protected $_messages = array();
protected function _convert($currencyFrom, $currencyTo, $retry=0)
{
$url = str_replace(‘{{CURRENCY_FROM}}’, $currencyFrom, $this->_url);
$url = str_replace(‘{{CURRENCY_TO}}’, $currencyTo, $url);
try {
sleep(1); //Be nice to Yahoo, they don’t have a lot of hi-spec servers
$handle = fopen($url, "r");
$exchange_rate = fread($handle, 2000);
fclose($handle);
if( !$exchange_rate ) {
$this->_messages[] = Mage::<span>helper(‘directory’)->__(‘Cannot retrieve rate from %s’, $url);
return null;
}
return (float) $exchange_rate * 1.0; // change 1.0 to influence rate;
}
catch (Exception $e) {
if( $retry == 0 ) {
$this->_convert($currencyFrom, $currencyTo, 1);
} else {
$this->_messages[] = Mage::<span>helper(‘directory’)->__(‘Cannot retrieve rate from %s’, $url);
}
}
}
} [/code]

Step 3 – Amend local.xml

That’s /app/etc/local.xml – add this inside the <global> tag (at the end of it, before the </global> tag):

[code]
<!– JT Yahoo Finance Integration–>
<currency>
<import>
<services>
<yahoofinance>
<name>Yahoo Finance</name>
<model>JT_Directory_Model_Currency_Import_Yahoofinance</model>
</yahoofinance>
</services>
</import>
</currency>
<!– EOF JT Yahoo Finance Integration–>
[/code]

Step 4 – Run it!

(You may have to flush your Configuration Cache first: System > Cache Management – Untick Configuration > Save > Tick it again > Save)

In your Magento Admin go to System > Manage Currency Rates

In the drop-down, Webservicex is still the top one so simply select Yahoo Finance from there and click the Import button.
Step 5 – Optional – Cron Setup

In Admin under System > Configuration go to Currency Setup under the Default Configuration scope. Enable the cron for Yahoo Finance here under Scheduled Import Settings (I’ve not yet tested this).
Important Notes

Just to not piss off Yahoo, there’s a sleep(1) one second interval built in. If you only use two or three currencies, you won’t even notice this delay. If like me you use 23 currencies, this may make it look slow but at least you’ll avoid potential auto-throttling and/or Yahoo! firewall banning by making requests look more “real”.

Yahoo! supplies these rates in csv files to the public. It’s up to you whether you ass-u-me that you can now use them in an automated fashion for commercial benefit or kindly request permission, or at least read the small print.

Note line 55 where the exchange rate is being returned. By default it’s returned as is, but some may want to influence this. For example, right now Yahoo! reckons one GBP is worth 1.1157 EUR. A 100 Pound item will be displayed as 115.70 Euro. When paying by bank transfer or credit card, they will be surprised when they read their bank statements as the bank’s rate will be more like 1.19 so they get deducted the grand sum of 119 Euro for that product. They may think you are falsely advertising the rates and pocketing the difference, even though your T’s & C’s will mention this possible discrepancy. So with this rate influencer ratio, you can dampen the fun a bit by using for example 1.049 instead of 1.0 (that allows for 4.9% mark-up by the banks). Now the products will look more expensive but there won’t be any surprises on their bank statements.

Source :http://www.magentocommerce.com/