<?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) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: Abstract.php 20096 2010-01-06 02:05:09Z bkarwin $

 */

/**

 * @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) 2005-2010 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);

        }

    }

}