text: <?php
  /**
   * Zend Framework
   *
   * LICENSE
   *
   * This source file is subject to the new BSD license that is bundled
   * with this package in the file LICENSE.txt.
   * It is also available through the world-wide-web at this URL:
   * http://framework.zend.com/license/new-bsd
   * 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@zend.com so we can send you a copy immediately.
   *
   * @category   Zend
   * @package    Zend_Service_Amazon
   * @subpackage Ec2
   * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
   * @license    http://framework.zend.com/license/new-bsd     New BSD License
   * @version    $Id: Abstract.php 23775 2011-03-01 17:25:24Z ralph $
   */
  
  /**
   * @see Zend_Service_Amazon_Abstract
   */
  require_once 'Zend/Service/Amazon/Abstract.php';
  
  /**
   * @see Zend_Service_Amazon_Ec2_Response
   */
  require_once 'Zend/Service/Amazon/Ec2/Response.php';
  
  /**
   * @see Zend_Service_Amazon_Ec2_Exception
   */
  require_once 'Zend/Service/Amazon/Ec2/Exception.php';
  
  /**
   * Provides the basic functionality to send a request to the Amazon Ec2 Query API
   *
   * @category   Zend
   * @package    Zend_Service_Amazon
   * @subpackage Ec2
   * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
   * @license    http://framework.zend.com/license/new-bsd     New BSD License
   */
  abstract class Zend_Service_Amazon_Ec2_Abstract extends Zend_Service_Amazon_Abstract
  {
      /**
       * The HTTP query server
       */
      protected $_ec2Endpoint = 'ec2.amazonaws.com';
  
      /**
       * The API version to use
       */
      protected $_ec2ApiVersion = '2009-04-04';
  
      /**
       * Signature Version
       */
      protected $_ec2SignatureVersion = '2';
  
      /**
       * Signature Encoding Method
       */
      protected $_ec2SignatureMethod = 'HmacSHA256';
  
      /**
       * Period after which HTTP request will timeout in seconds
       */
      protected $_httpTimeout = 10;
  
      /**
       * @var string Amazon Region
       */
      protected static $_defaultRegion = null;
  
      /**
       * @var string Amazon Region
       */
      protected $_region;
  
      /**
       * An array that contains all the valid Amazon Ec2 Regions.
       *
       * @var array
       */
      protected static $_validEc2Regions = array('eu-west-1', 'us-east-1');
  
      /**
       * Create Amazon client.
       *
       * @param  string $access_key       Override the default Access Key
       * @param  string $secret_key       Override the default Secret Key
       * @param  string $region           Sets the AWS Region
       * @return void
       */
      public function __construct($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);
      }
  
      /**
       * Set which region you are working in.  It will append the
       * end point automaticly
       *
       * @param string $region
       */
      public static function setRegion($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');
          }
      }
  
      /**
       * Method to fetch the AWS Region
       *
       * @return string
       */
      protected function _getRegion()
      {
          return (!empty($this->_region)) ? $this->_region . '.' : '';
      }
  
      /**
       * Sends a HTTP request to the queue service using Zend_Http_Client
       *
       * @param array $params         List of parameters to send with the request
       * @return Zend_Service_Amazon_Ec2_Response
       * @throws Zend_Service_Amazon_Ec2_Exception
       */
      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;
      }
  
      /**
       * Adds required authentication and version parameters to an array of
       * parameters
       *
       * The required parameters are:
       * - AWSAccessKey
       * - SignatureVersion
       * - Timestamp
       * - Version and
       * - Signature
       *
       * If a required parameter is already set in the <tt>$parameters</tt> array,
       * it is overwritten.
       *
       * @param array $parameters the array to which to add the required
       *                          parameters.
       *
       * @return array
       */
      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;
      }
  
      /**
       * Computes the RFC 2104-compliant HMAC signature for request parameters
       *
       * This implements the Amazon Web Services signature, as per the following
       * specification:
       *
       * 1. Sort all request parameters (including <tt>SignatureVersion</tt> and
       *    excluding <tt>Signature</tt>, the value of which is being created),
       *    ignoring case.
       *
       * 2. Iterate over the sorted list and append the parameter name (in its
       *    original case) and then its value. Do not URL-encode the parameter
       *    values before constructing this string. Do not use any separator
       *    characters when appending strings.
       *
       * @param array  $parameters the parameters for which to get the signature.
       * @param string $secretKey  the secret key to use to sign the parameters.
       *
       * @return string the signed data.
       */
      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);
      }
  
      /**
       * Checks for errors responses from Amazon
       *
       * @param Zend_Service_Amazon_Ec2_Response $response the response object to
       *                                                   check.
       *
       * @return void
       *
       * @throws Zend_Service_Amazon_Ec2_Exception if one or more errors are
       *         returned from Amazon.
       */
      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);
          }
  
      }
  }
  