C:/xampp/htdocs/moodle/lib/zend/Zend/Service/Amazon/Ec2/Abstract.php

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<?php
require_once 'Zend/Service/Amazon/Abstract.php';

require_once 'Zend/Service/Amazon/Ec2/Response.php';

require_once 'Zend/Service/Amazon/Ec2/Exception.php';

abstract class Zend_Service_Amazon_Ec2_Abstract extends Zend_Service_Amazon_Abstract
{
    protected $_ec2Endpoint = 'ec2.amazonaws.com';

    protected $_ec2ApiVersion = '2009-04-04';

    protected $_ec2SignatureVersion = '2';

    protected $_ec2SignatureMethod = 'HmacSHA256';

    protected $_httpTimeout = 10;

    protected static $_defaultRegion = null;

    protected $_region;

    protected static $_validEc2Regions = array('eu-west-1', 'us-east-1');

    public function __construct($accessKey=null, $secretKey=null, $region=null)
    {
        if(!$region) {
            $region = self::$_defaultRegion;
        } else {
            // make rue the region is valid
            if(!empty($region) && !in_array(strtolower($region), self::$_validEc2Regions, true)) {
                require_once 'Zend/Service/Amazon/Exception.php';
                throw new Zend_Service_Amazon_Exception('Invalid Amazon Ec2 Region');
            }
        }

        $this->_region = $region;

        parent::__construct($accessKey, $secretKey);
    }

    public static function setRegion($region)
    {
        if(in_array(strtolower($region), self::$_validEc2Regions, true)) {
            self::$_defaultRegion = $region;
        } else {
            require_once 'Zend/Service/Amazon/Exception.php';
            throw new Zend_Service_Amazon_Exception('Invalid Amazon Ec2 Region');
        }
    }

    protected function _getRegion()
    {
        return (!empty($this->_region)) ? $this->_region . '.' : '';
    }

    protected function sendRequest(array $params = array())
    {
        $url = 'https://' . $this->_getRegion() . $this->_ec2Endpoint . '/';

        $params = $this->addRequiredParameters($params);

        try {
            /* @var $request Zend_Http_Client */
            $request = self::getHttpClient();
            $request->resetParameters();

            $request->setConfig(array(
                'timeout' => $this->_httpTimeout
            ));

            $request->setUri($url);
            $request->setMethod(Zend_Http_Client::POST);
            $request->setParameterPost($params);

            $httpResponse = $request->request();


        } catch (Zend_Http_Client_Exception $zhce) {
            $message = 'Error in request to AWS service: ' . $zhce->getMessage();
            throw new Zend_Service_Amazon_Ec2_Exception($message, $zhce->getCode(), $zhce);
        }
        $response = new Zend_Service_Amazon_Ec2_Response($httpResponse);
        $this->checkForErrors($response);

        return $response;
    }

    protected function addRequiredParameters(array $parameters)
    {
        $parameters['AWSAccessKeyId']   = $this->_getAccessKey();
        $parameters['SignatureVersion'] = $this->_ec2SignatureVersion;
        $parameters['Timestamp']        = gmdate('Y-m-d\TH:i:s\Z');
        $parameters['Version']          = $this->_ec2ApiVersion;
        $parameters['SignatureMethod']  = $this->_ec2SignatureMethod;
        $parameters['Signature']        = $this->signParameters($parameters);

        return $parameters;
    }

    protected function signParameters(array $paramaters)
    {
        $data = "POST\n";
        $data .= $this->_getRegion() . $this->_ec2Endpoint . "\n";
        $data .= "/\n";

        uksort($paramaters, 'strcmp');
        unset($paramaters['Signature']);

        $arrData = array();
        foreach($paramaters as $key => $value) {
            $arrData[] = $key . '=' . str_replace("%7E", "~", rawurlencode($value));
        }

        $data .= implode('&', $arrData);

        require_once 'Zend/Crypt/Hmac.php';
        $hmac = Zend_Crypt_Hmac::compute($this->_getSecretKey(), 'SHA256', $data, Zend_Crypt_Hmac::BINARY);

        return base64_encode($hmac);
    }

    private function checkForErrors(Zend_Service_Amazon_Ec2_Response $response)
    {
        $xpath = new DOMXPath($response->getDocument());
        $list  = $xpath->query('//Error');
        if ($list->length > 0) {
            $node    = $list->item(0);
            $code    = $xpath->evaluate('string(Code/text())', $node);
            $message = $xpath->evaluate('string(Message/text())', $node);
            throw new Zend_Service_Amazon_Ec2_Exception($message, 0, $code);
        }

    }
}