<?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

 * @subpackage Amazon_Sqs

 * @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: Sqs.php 22984 2010-09-21 02:52:48Z matthew $

 */

/**

 * @see Zend_Service_Amazon_Abstract

 */

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

/**

 * @see Zend_Crypt_Hmac

 */

require_once 'Zend/Crypt/Hmac.php';

/**

 * Class for connecting to the Amazon Simple Queue Service (SQS)

 *

 * @category   Zend

 * @package    Zend_Service

 * @subpackage Amazon_Sqs

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

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

 * @see        http://aws.amazon.com/sqs/ Amazon Simple Queue Service

 */

class Zend_Service_Amazon_Sqs extends Zend_Service_Amazon_Abstract

{

    /**

     * Default timeout for createQueue() function

     */

    const CREATE_TIMEOUT_DEFAULT = 30;

    /**

     * HTTP end point for the Amazon SQS service

     */

    protected $_sqsEndpoint = 'queue.amazonaws.com';

    /**

     * The API version to use

     */

    protected $_sqsApiVersion = '2009-02-01';

    /**

     * Signature Version

     */

    protected $_sqsSignatureVersion = '2';

    /**

     * Signature Encoding Method

     */

    protected $_sqsSignatureMethod = 'HmacSHA256';

    /**

     * Constructor

     *

     * @param string $accessKey

     * @param string $secretKey

     * @param string $region

     */

    public function __construct($accessKey = null, $secretKey = null, $region = null)

    {

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

    }

    /**

     * Create a new queue

     *

     * Visibility timeout is how long a message is left in the queue "invisible"

     * to other readers.  If the message is acknowleged (deleted) before the

     * timeout, then the message is deleted.  However, if the timeout expires

     * then the message will be made available to other queue readers.

     *

     * @param  string  $queue_name queue name

     * @param  integer $timeout    default visibility timeout

     * @return string|boolean

     * @throws Zend_Service_Amazon_Sqs_Exception

     */

    public function create($queue_name, $timeout = null)

    {

        $params = array();

        $params['QueueName'] = $queue_name;

        $timeout = ($timeout === null) ? self::CREATE_TIMEOUT_DEFAULT : (int)$timeout;

        $params['DefaultVisibilityTimeout'] = $timeout;

        $retry_count = 0;

        do {

            $retry  = false;

            $result = $this->_makeRequest(null, 'CreateQueue', $params);

            if (!isset($result->CreateQueueResult->QueueUrl)

                || empty($result->CreateQueueResult->QueueUrl)

            ) {

                if ($result->Error->Code == 'AWS.SimpleQueueService.QueueNameExists') {

                    return false;

                } elseif ($result->Error->Code == 'AWS.SimpleQueueService.QueueDeletedRecently') {

                    // Must sleep for 60 seconds, then try re-creating the queue

                    sleep(60);

                    $retry = true;

                    $retry_count++;

                } else {

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

                    throw new Zend_Service_Amazon_Sqs_Exception($result->Error->Code);

                }

            } else {

                return (string) $result->CreateQueueResult->QueueUrl;

            }

        } while ($retry);

        return false;

    }

    /**

     * Delete a queue and all of it's messages

     *

     * Returns false if the queue is not found, true if the queue exists

     *

     * @param  string  $queue_url queue URL

     * @return boolean

     * @throws Zend_Service_Amazon_Sqs_Exception

     */

    public function delete($queue_url)

    {

        $result = $this->_makeRequest($queue_url, 'DeleteQueue');

        if ($result->Error->Code !== null) {

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

            throw new Zend_Service_Amazon_Sqs_Exception($result->Error->Code);

        }

        return true;

    }

    /**

     * Get an array of all available queues

     *

     * @return array

     * @throws Zend_Service_Amazon_Sqs_Exception

     */

    public function getQueues()

    {

        $result = $this->_makeRequest(null, 'ListQueues');

        if (isset($result->Error)) {

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

            throw new Zend_Service_Amazon_Sqs_Exception($result->Error->Code);

        }

        if (!isset($result->ListQueuesResult->QueueUrl)

            || empty($result->ListQueuesResult->QueueUrl)

        ) {

            return array();

        }

        $queues = array();

        foreach ($result->ListQueuesResult->QueueUrl as $queue_url) {

            $queues[] = (string)$queue_url;

        }

        return $queues;

    }

    /**

     * Return the approximate number of messages in the queue

     *

     * @param  string  $queue_url Queue URL

     * @return integer

     * @throws Zend_Service_Amazon_Sqs_Exception

     */

    public function count($queue_url)

    {

        return (int)$this->getAttribute($queue_url, 'ApproximateNumberOfMessages');

    }

    /**

     * Send a message to the queue

     *

     * @param  string $queue_url Queue URL

     * @param  string $message   Message to send to the queue

     * @return string            Message ID

     * @throws Zend_Service_Amazon_Sqs_Exception

     */

    public function send($queue_url, $message)

    {

        $params = array();

        $params['MessageBody'] = urlencode($message);

        $checksum = md5($params['MessageBody']);

        $result = $this->_makeRequest($queue_url, 'SendMessage', $params);

        if (!isset($result->SendMessageResult->MessageId)

            || empty($result->SendMessageResult->MessageId)

        ) {

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

            throw new Zend_Service_Amazon_Sqs_Exception($result->Error->Code);

        } else if ((string) $result->SendMessageResult->MD5OfMessageBody != $checksum) {

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

            throw new Zend_Service_Amazon_Sqs_Exception('MD5 of body does not match message sent');

        }

        return (string) $result->SendMessageResult->MessageId;

    }

    /**

     * Get messages in the queue

     *

     * @param  string  $queue_url    Queue name

     * @param  integer $max_messages Maximum number of messages to return

     * @param  integer $timeout      Visibility timeout for these messages

     * @return array

     * @throws Zend_Service_Amazon_Sqs_Exception

     */

    public function receive($queue_url, $max_messages = null, $timeout = null)

    {

        $params = array();

        // If not set, the visibility timeout on the queue is used

        if ($timeout !== null) {

            $params['VisibilityTimeout'] = (int)$timeout;

        }

        // SQS will default to only returning one message

        if ($max_messages !== null) {

            $params['MaxNumberOfMessages'] = (int)$max_messages;

        }

        $result = $this->_makeRequest($queue_url, 'ReceiveMessage', $params);

        if (isset($result->Error)) {

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

            throw new Zend_Service_Amazon_Sqs_Exception($result->Error->Code);

        }

        if (!isset($result->ReceiveMessageResult->Message)

            || empty($result->ReceiveMessageResult->Message)

        ) {

            // no messages found

            return array();

        }

        $data = array();

        foreach ($result->ReceiveMessageResult->Message as $message) {

            $data[] = array(

                'message_id' => (string)$message->MessageId,

                'handle'     => (string)$message->ReceiptHandle,

                'md5'        => (string)$message->MD5OfBody,

                'body'       => urldecode((string)$message->Body),

            );

        }

        return $data;

    }

    /**

     * Delete a message from the queue

     *

     * Returns true if the message is deleted, false if the deletion is

     * unsuccessful.

     *

     * @param  string $queue_url  Queue URL

     * @param  string $handle     Message handle as returned by SQS

     * @return boolean

     * @throws Zend_Service_Amazon_Sqs_Exception

     */

    public function deleteMessage($queue_url, $handle)

    {

        $params = array();

        $params['ReceiptHandle'] = (string)$handle;

        $result = $this->_makeRequest($queue_url, 'DeleteMessage', $params);

        if (isset($result->Error->Code) 

            && !empty($result->Error->Code)

        ) {

            return false;

        }

        // Will always return true unless ReceiptHandle is malformed

        return true;

    }

    /**

     * Get the attributes for the queue

     *

     * @param  string $queue_url  Queue URL

     * @param  string $attribute

     * @return string

     * @throws Zend_Service_Amazon_Sqs_Exception

     */

    public function getAttribute($queue_url, $attribute = 'All')

    {

        $params = array();

        $params['AttributeName'] = $attribute;

        $result = $this->_makeRequest($queue_url, 'GetQueueAttributes', $params);

        if (!isset($result->GetQueueAttributesResult->Attribute)

            || empty($result->GetQueueAttributesResult->Attribute)

        ) {

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

            throw new Zend_Service_Amazon_Sqs_Exception($result->Error->Code);

        }

        if(count($result->GetQueueAttributesResult->Attribute) > 1) {

            $attr_result = array();

            foreach($result->GetQueueAttributesResult->Attribute as $attribute) {

                $attr_result[(string)$attribute->Name] = (string)$attribute->Value;

            }

            return $attr_result;

        } else {

            return (string) $result->GetQueueAttributesResult->Attribute->Value;

        }

    }

    /**

     * Make a request to Amazon SQS

     *

     * @param  string           $queue  Queue Name

     * @param  string           $action SQS action

     * @param  array            $params

     * @return SimpleXMLElement

     */

    private function _makeRequest($queue_url, $action, $params = array())

    {

        $params['Action'] = $action;

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

        if ($queue_url === null) {

            $queue_url = '/';

        }

        $client = self::getHttpClient();

        switch ($action) {

            case 'ListQueues':

            case 'CreateQueue':

                $client->setUri('http://'.$this->_sqsEndpoint);

                break;

            default:

                $client->setUri($queue_url);

                break;

        }

        $retry_count = 0;

        do {

            $retry = false;

            $client->resetParameters();

            $client->setParameterGet($params);

            $response = $client->request('GET');

            $response_code = $response->getStatus();

            // Some 5xx errors are expected, so retry automatically

            if ($response_code >= 500 && $response_code < 600 && $retry_count <= 5) {

                $retry = true;

                $retry_count++;

                sleep($retry_count / 4 * $retry_count);

            }

        } while ($retry);

        unset($client);

        return new SimpleXMLElement($response->getBody());

    }

    /**

     * 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  string $queue_url  Queue URL

     * @param  array  $parameters the array to which to add the required

     *                            parameters.

     * @return array

     */

    protected function addRequiredParameters($queue_url, array $parameters)

    {

        $parameters['AWSAccessKeyId']   = $this->_getAccessKey();

        $parameters['SignatureVersion'] = $this->_sqsSignatureVersion;

        $parameters['Timestamp']        = gmdate('Y-m-d\TH:i:s\Z', time()+10);

        $parameters['Version']          = $this->_sqsApiVersion;

        $parameters['SignatureMethod']  = $this->_sqsSignatureMethod;

        $parameters['Signature']        = $this->_signParameters($queue_url, $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  string $queue_url  Queue URL

     * @param  array  $parameters the parameters for which to get the signature.

     *

     * @return string the signed data.

     */

    protected function _signParameters($queue_url, array $paramaters)

    {

        $data = "GET\n";