source: trunk/lib/Currency.inc.php @ 334

<?php
/**
 * Currency.inc.php
 * code by strangecode :: www.strangecode.com :: this document contains copyrighted information
 *
 * Class to convert currency values.
 *
 * @author  Quinn Comendant <quinn@strangecode.com>
 * @version 1.0
 * 
 * Example of use:
---------------------------------------------------------------------
$currency = new Currency();
echo $currency->getValue(1, 'eur', 'usd');
---------------------------------------------------------------------
 */

require_once 'SOAP/Client.php';
 
class Currency {

    // Configuration parameters for this object.
    var $_params = array(
        'cache_result' => true,
        'cache_dir' => '',
        'cache_age' => 28800, // 8 hours.
        'soap_api_url' => 'http://xurrency.com/servidor_soap.php',
    );
    
    // Object to hold SOAP_Client instance.
    var $_soap_client;

    /**
     * Cart constructor.
     */
    function Currency($params=array())
    {
        $app =& App::getInstance();

        // Initialize.
        if (!isset($_SESSION['_currency'])) {
            $_SESSION['_currency'] = array();
        }

        // Set custom parameters.
        $this->setParam($params);
        
        // Setup cache directory.
        if ($this->getParam('cache_result')) {
            if ('' == $this->getParam('cache_dir')) {
                // Use a sane default cache directory.
                $this->setParam(array('cache_dir' => '/tmp/xcache_' . md5(COMMON_BASE)));
            }
            if (!is_dir($this->getParam('cache_dir'))) {
                $app->logMsg(sprintf('Creating cache_dir: %s', $this->getParam('cache_dir')), LOG_INFO, __FILE__, __LINE__);                
                if (!mkdir($this->getParam('cache_dir'))) {
                    $app->logMsg(sprintf('Could not create cache_dir: %s', $this->getParam('cache_dir')), LOG_WARNING, __FILE__, __LINE__);                
                }
            }
        }
        
        // Setup SOAP object.
        $this->_soap_client = new SOAP_Client($this->getParam('soap_api_url'));
    }

    /**
     * Set the params of this object.
     *
     * @param  array $params   Array of param keys and values to set.
     */
    function setParam($params=null)
    {
        if (isset($params) && is_array($params)) {
            // Merge new parameters with old overriding only those passed.
            $this->_params = array_merge($this->_params, $params);
        }
    }

    /**
     * Return the value of a parameter, if it exists.
     *
     * @access public
     * @param string $param        Which parameter to return.
     * @return mixed               Configured parameter value.
     */
    function getParam($param)
    {
        $app =& App::getInstance();
    
        if (isset($this->_params[$param])) {
            return $this->_params[$param];
        } else {
            $app->logMsg(sprintf('Parameter is not set: %s', $param), LOG_DEBUG, __FILE__, __LINE__);
            return null;
        }
    }
    
    /*
    * Return the exchange value between the two given currencies.
    *
    * @access   public
    * @param    float   Base amount to convert from.
    * @param    string  3-letter currency code to convert from.
    * @param    string  3-letter currency code to convert to.
    * @return   mixed   Float exchange rate value, or false on error. 
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    05 May 2008 23:50:59
    */
    function getValue($amount, $base, $target)
    {
        $app =& App::getInstance();

        $cache_file_path = sprintf('%s/%s-to-%s', $this->getParam('cache_dir'), $base, $target);
        $cache_file_mtime = @filemtime($cache_file_path);
        if (!$this->getParam('cache_result') || !$cache_file_mtime || $cache_file_mtime < time() - $this->getParam('cache_age')) {
            // Get fresh data and create cached file if missing or expired.
            $app->logMsg(sprintf('Getting fresh currency exchange rates: %s-to-%s', $base, $target), LOG_DEBUG, __FILE__, __LINE__);
            $value = $this->_performAPICall('getValue', array(
                'amount' => $amount,
                'base' => $base,
                'target' => $target
            ));
            if (false === $value || !is_numeric($value)) {
                // Failed retrieving SOAP value. Use cached copy for now.
                $app->logMsg(sprintf('Failed getting SOAP currency exchange rates: %s-to-%s, using cached copy', $base, $target), LOG_NOTICE, __FILE__, __LINE__);
                if (!$value = file_get_contents($cache_file_path)) {
                    $app->logMsg(sprintf('Failed reading target rate file: %s', $cache_file_path), LOG_ERR, __FILE__, __LINE__);
                    return false;
                }
            } else if ($this->getParam('cache_result') && !filePutContents($cache_file_path, $value, LOCK_EX)) {
                $app->logMsg(sprintf('Failed writing to target rate file: %s', $cache_file_path), LOG_ERR, __FILE__, __LINE__);
                return false;
            }
        } else {
            $app->logMsg(sprintf('Getting cached currency exchange rates: %s-to-%s', $base, $target), LOG_DEBUG, __FILE__, __LINE__);
            if (!$value = file_get_contents($cache_file_path)) {
                $app->logMsg(sprintf('Failed reading target rate file: %s', $cache_file_path), LOG_ERR, __FILE__, __LINE__);
                return false;
            }
        }
        return trim($value);
    }
    
    /**
     * @param  string
     * @param  array
     * @return mixed
     * @access private
     */
    function _performAPICall($api_call, $parameters=null)
    {
        $app =& App::getInstance();
        
        $result = $this->_soap_client->call($api_call, $parameters);
        
        if (PEAR::isError($result)) {
            $app->logMsg(sprintf('SOAP Pear error: %s', $result->getMessage()), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        return $result;
    }
}


?>