Magento currency Converter - php

Question

I am implementing custom filter by price range functionality on product list page in magento
I have multiple currency store, and base currency is INR , with other 6 to 7 currencies
I take input from price range and using following filter on product collection
$this->_productCollection = $layer->getProductCollection();
if($this->getRequest()->getParam('filterPrice')){
$baseCurrency = Mage::app()->getStore()->getBaseCurrencyCode();
$currentCurrency = Mage::app()->getStore()->getCurrentCurrencyCode();
$price = explode('-',$this->getRequest()->getParam('filterPrice'));
$min = str_replace(Mage::app()->getLocale()->currency(Mage::app()->getStore()->getCurrentCurrencyCode())->getSymbol(),'',$price[0]);
$min = $this->currencyConverter($min, $currentCurrency, $baseCurrency);
$max = str_replace(Mage::app()->getLocale()->currency(Mage::app()->getStore()->getCurrentCurrencyCode())->getSymbol(),'',$price[1]);
$max = $this->currencyConverter($max, $currentCurrency, $baseCurrency);
$this->_productCollection->addAttributeToFilter('price',array('from'=>$min,'to'=>$max));
}
Where currencyConverter function is like
public function currencyConverter($amount,$from,$to)
{
if($from!=$to){
$targetCurrency = Mage::getModel('directory/currency')->load($to);
$price = Mage::helper('directory')->currencyConvert($amount, $from, $targetCurrency);
$converted_final_price = Mage::app()->getStore()->roundPrice($price);
return $converted_final_price;
}else{
return $amount;
}
}
but I am getting following error
Undefined rate from "CAD-INR".
From other threads , I get to know that I need to setup currencies and rates from magento backend ,and I implement the same, but still error remains same.

Answer 1

Magento have rates only for pairs "Base currency => Display Currency".
You have Base currency "INR" and you likely have rate for pair "INR => CAD".
Your error say that your code try to get rate for "CAD" currency and in your system you have not rate for "CAD => INR".
Please, make sure, that you try to convert price in base currency to any other currency, and not between two display currencies.
But if you need this, you should use your own convert function, that calculates neccessary rate.