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core/model/aws/sdk.class.php

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<?php
/*
 * Copyright 2010-2011 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */


/*%******************************************************************************************%*/
// CORE DEPENDENCIES

// Look for include file in the same directory (e.g. `./config.inc.php`).
if (file_exists(dirname(__FILE__) . DIRECTORY_SEPARATOR . 'config.inc.php'))
{
    include_once dirname(__FILE__) . DIRECTORY_SEPARATOR . 'config.inc.php';
}
// Fallback to `~/.aws/sdk/config.inc.php`
elseif (getenv('HOME') && file_exists(getenv('HOME') . DIRECTORY_SEPARATOR . '.aws' . DIRECTORY_SEPARATOR . 'sdk' . DIRECTORY_SEPARATOR . 'config.inc.php'))
{
    include_once getenv('HOME') . DIRECTORY_SEPARATOR . '.aws' . DIRECTORY_SEPARATOR . 'sdk' . DIRECTORY_SEPARATOR . 'config.inc.php';
}


/*%******************************************************************************************%*/
// EXCEPTIONS

/**
 * Default CFRuntime Exception.
 */
class CFRuntime_Exception extends Exception {}


/*%******************************************************************************************%*/
// DETERMINE WHAT ENVIRONMENT DATA TO ADD TO THE USERAGENT FOR METRIC TRACKING

/*
    Define a temporary callback function for this calculation. Get the PHP version and any
    required/optional extensions that are leveraged.

    Tracking this data gives Amazon better metrics about what configurations are being used
    so that forward-looking plans for the code can be made with more certainty (e.g. What
    version of PHP are most people running? Do they tend to have the latest PCRE?).
*/
function __aws_sdk_ua_callback()
{
    $ua_append = '';
    $extensions = get_loaded_extensions();
    $sorted_extensions = array();

    if ($extensions)
    {
        foreach ($extensions as $extension)
        {
            if ($extension === 'curl' && function_exists('curl_version'))
            {
                $curl_version = curl_version();
                $sorted_extensions[strtolower($extension)] = $curl_version['version'];
            }
            elseif ($extension === 'pcre' && defined('PCRE_VERSION'))
            {
                $pcre_version = explode(' ', PCRE_VERSION);
                $sorted_extensions[strtolower($extension)] = $pcre_version[0];
            }
            elseif ($extension === 'openssl' && defined('OPENSSL_VERSION_TEXT'))
            {
                $openssl_version = explode(' ', OPENSSL_VERSION_TEXT);
                $sorted_extensions[strtolower($extension)] = $openssl_version[1];
            }
            else
            {
                $sorted_extensions[strtolower($extension)] = phpversion($extension);
            }
        }
    }

    foreach (array('simplexml', 'json', 'pcre', 'spl', 'curl', 'openssl', 'apc', 'xcache', 'memcache', 'memcached', 'pdo', 'pdo_sqlite', 'sqlite', 'sqlite3', 'zlib', 'xdebug') as $ua_ext)
    {
        if (isset($sorted_extensions[$ua_ext]) && $sorted_extensions[$ua_ext])
        {
            $ua_append .= ' ' . $ua_ext . '/' . $sorted_extensions[$ua_ext];
        }
        elseif (isset($sorted_extensions[$ua_ext]))
        {
            $ua_append .= ' ' . $ua_ext . '/0';
        }
    }

    foreach (array('memory_limit', 'date.timezone', 'open_basedir', 'safe_mode', 'zend.enable_gc') as $cfg)
    {
        $cfg_value = get_cfg_var($cfg);

        if (in_array($cfg, array('memory_limit', 'date.timezone'), true))
        {
            $ua_append .= ' ' . $cfg . '/' . str_replace('/', '.', $cfg_value);
        }
        elseif (in_array($cfg, array('open_basedir', 'safe_mode', 'zend.enable_gc'), true))
        {
            if ($cfg_value === false || $cfg_value === '' || $cfg_value === 0)
            {
                $cfg_value = 'off';
            }
            elseif ($cfg_value === true || $cfg_value === '1' || $cfg_value === 1)
            {
                $cfg_value = 'on';
            }

            $ua_append .= ' ' . $cfg . '/' . $cfg_value;
        }
    }

    return $ua_append;
}


/*%******************************************************************************************%*/
// INTERMEDIARY CONSTANTS

define('CFRUNTIME_NAME', 'aws-sdk-php');
define('CFRUNTIME_VERSION', '1.4.1');
// define('CFRUNTIME_BUILD', gmdate('YmdHis', filemtime(__FILE__))); // @todo: Hardcode for release.
define('CFRUNTIME_BUILD', '20110823204245');
define('CFRUNTIME_USERAGENT', CFRUNTIME_NAME . '/' . CFRUNTIME_VERSION . ' PHP/' . PHP_VERSION . ' ' . str_replace(' ', '_', php_uname('s')) . '/' . str_replace(' ', '_', php_uname('r')) . ' Arch/' . php_uname('m') . ' SAPI/' . php_sapi_name() . ' Integer/' . PHP_INT_MAX . ' Build/' . CFRUNTIME_BUILD . __aws_sdk_ua_callback());


/*%******************************************************************************************%*/
// CLASS

/**
 * Core functionality and default settings shared across all SDK classes. All methods and properties in this
 * class are inherited by the service-specific classes.
 *
 * @version 2011.07.28
 * @license See the included NOTICE.md file for more information.
 * @copyright See the included NOTICE.md file for more information.
 * @link http://aws.amazon.com/php/ PHP Developer Center
 */
class CFRuntime
{
    /*%******************************************************************************************%*/
    // CONSTANTS

    /**
     * Name of the software.
     */
    const NAME = CFRUNTIME_NAME;

    /**
     * Version of the software.
     */
    const VERSION = CFRUNTIME_VERSION;

    /**
     * Build ID of the software.
     */
    const BUILD = CFRUNTIME_BUILD;

    /**
     * User agent string used to identify the software.
     */
    const USERAGENT = CFRUNTIME_USERAGENT;


    /*%******************************************************************************************%*/
    // PROPERTIES

    /**
     * The Amazon API Key.
     */
    public $key;

    /**
     * The Amazon API Secret Key.
     */
    public $secret_key;

    /**
     * The Amazon Authentication Token.
     */
    public $auth_token;

    /**
     * The Amazon Account ID, without hyphens.
     */
    public $account_id;

    /**
     * The Amazon Associates ID.
     */
    public $assoc_id;

    /**
     * Handle for the utility functions.
     */
    public $util;

    /**
     * An identifier for the current AWS service.
     */
    public $service = null;

    /**
     * The supported API version.
     */
    public $api_version = null;

    /**
     * The state of whether auth should be handled as AWS Query.
     */
    public $use_aws_query = true;

    /**
     * The default class to use for utilities (defaults to <CFUtilities>).
     */
    public $utilities_class = 'CFUtilities';

    /**
     * The default class to use for HTTP requests (defaults to <CFRequest>).
     */
    public $request_class = 'CFRequest';

    /**
     * The default class to use for HTTP responses (defaults to <CFResponse>).
     */
    public $response_class = 'CFResponse';

    /**
     * The default class to use for parsing XML (defaults to <CFSimpleXML>).
     */
    public $parser_class = 'CFSimpleXML';

    /**
     * The default class to use for handling batch requests (defaults to <CFBatchRequest>).
     */
    public $batch_class = 'CFBatchRequest';

    /**
     * The number of seconds to adjust the request timestamp by (defaults to 0).
     */
    public $adjust_offset = 0;

    /**
     * The state of SSL/HTTPS use.
     */
    public $use_ssl = true;

    /**
     * The state of SSL certificate verification.
     */
    public $ssl_verification = true;

    /**
     * The proxy to use for connecting.
     */
    public $proxy = null;

    /**
     * The alternate hostname to use, if any.
     */
    public $hostname = null;

    /**
     * The state of the capability to override the hostname with <set_hostname()>.
     */
    public $override_hostname = true;

    /**
     * The alternate port number to use, if any.
     */
    public $port_number = null;

    /**
     * The alternate resource prefix to use, if any.
     */
    public $resource_prefix = null;

    /**
     * The state of cache flow usage.
     */
    public $use_cache_flow = false;

    /**
     * The caching class to use.
     */
    public $cache_class = null;

    /**
     * The caching location to use.
     */
    public $cache_location = null;

    /**
     * When the cache should be considered stale.
     */
    public $cache_expires = null;

    /**
     * The state of cache compression.
     */
    public $cache_compress = null;

    /**
     * The current instantiated cache object.
     */
    public $cache_object = null;

    /**
     * The current instantiated batch request object.
     */
    public $batch_object = null;

    /**
     * The internally instantiated batch request object.
     */
    public $internal_batch_object = null;

    /**
     * The state of batch flow usage.
     */
    public $use_batch_flow = false;

    /**
     * The state of the cache deletion setting.
     */
    public $delete_cache = false;

    /**
     * The state of the debug mode setting.
     */
    public $debug_mode = false;

    /**
     * The number of times to retry failed requests.
     */
    public $max_retries = 3;

    /**
     * The user-defined callback function to call when a stream is read from.
     */
    public $registered_streaming_read_callback = null;

    /**
     * The user-defined callback function to call when a stream is written to.
     */
    public $registered_streaming_write_callback = null;


    /*%******************************************************************************************%*/
    // CONSTRUCTOR

    /**
     * The constructor. You would not normally instantiate this class directly. Rather, you would instantiate
     * a service-specific class.
     *
     * @param string $key (Optional) Your AWS key, or a session key. If blank, it will look for the <code>AWS_KEY</code> constant.
     * @param string $secret_key (Optional) Your AWS secret key, or a session secret key. If blank, it will look for the <code>AWS_SECRET_KEY</code> constant.
     * @param string $token (optional) An AWS session token. If blank, a request will be made to the AWS Secure Token Service to fetch a set of session credentials.
     * @return boolean A value of `false` if no valid values are set, otherwise `true`.
     */
    public function __construct($key = null, $secret_key = null, $token = null)
    {
        // Instantiate the utilities class.
        $this->util = new $this->utilities_class();

        // Determine the current service.
        $this->service = get_class($this);

        // Set default values
        $this->key = null;
        $this->secret_key = null;

        // If both a key and secret key are passed in, use those.
        if ($key && $secret_key)
        {
            $this->key = $key;
            $this->secret_key = $secret_key;
            return true;
        }
        // If neither are passed in, look for the constants instead.
        elseif (defined('AWS_KEY') && defined('AWS_SECRET_KEY'))
        {
            $this->key = AWS_KEY;
            $this->secret_key = AWS_SECRET_KEY;
            return true;
        }

        // Otherwise set the values to blank and return false.
        else
        {
            throw new CFRuntime_Exception('No valid credentials were used to authenticate with AWS.');
        }
    }

    /**
     * Handle session-based authentication for services that support it.
     *
     * @param string $key (Optional) Your AWS key, or a session key. If blank, it will look for the <code>AWS_KEY</code> constant.
     * @param string $secret_key (Optional) Your AWS secret key, or a session secret key. If blank, it will look for the <code>AWS_SECRET_KEY</code> constant.
     * @param string $token (optional) An AWS session token. If blank, a request will be made to the AWS Secure Token Service to fetch a set of session credentials.
     * @return boolean A value of `false` if no valid values are set, otherwise `true`.
     */
    public function session_based_auth($key = null, $secret_key = null, $token = null)
    {
        // Instantiate the utilities class.
        $this->util = new $this->utilities_class();

        // Use 'em if we've got 'em
        if ($key && $secret_key && $token)
        {
            $this->key = $key;
            $this->secret_key = $secret_key;
            $this->auth_token = $token;
            return true;
        }
        else
        {
            if (!$key && !defined('AWS_KEY'))
            {
                // @codeCoverageIgnoreStart
                throw new CFRuntime_Exception('No account key was passed into the constructor, nor was it set in the AWS_KEY constant.');
                // @codeCoverageIgnoreEnd
            }

            if (!$secret_key && !defined('AWS_SECRET_KEY'))
            {
                // @codeCoverageIgnoreStart
                throw new CFRuntime_Exception('No account secret was passed into the constructor, nor was it set in the AWS_SECRET_KEY constant.');
                // @codeCoverageIgnoreEnd
            }

            // If both a key and secret key are passed in, use those.
            if ($key && $secret_key)
            {
                $this->key = $key;
                $this->secret_key = $secret_key;
            }
            // If neither are passed in, look for the constants instead.
            elseif (defined('AWS_KEY') && defined('AWS_SECRET_KEY'))
            {
                $this->key = AWS_KEY;
                $this->secret_key = AWS_SECRET_KEY;
            }

            // Determine storage type.
            $this->set_cache_config(AWS_DEFAULT_CACHE_CONFIG);
            $cache_class = $this->cache_class;
            $cache_object = new $cache_class('aws_active_session_credentials_' . get_class($this) . '_' . $this->key, AWS_DEFAULT_CACHE_CONFIG, 3600); // AWS_DEFAULT_CACHE_CONFIG only matters if it's a file system path.

            // Fetch session credentials
            $session_credentials = $cache_object->response_manager(array($this, 'cache_token'), array($this->key, $this->secret_key));
            $this->auth_token = $session_credentials['SessionToken'];

            // If both a key and secret key are passed in, use those.
            if (isset($session_credentials['AccessKeyId']) && isset($session_credentials['SecretAccessKey']))
            {
                $this->key = $session_credentials['AccessKeyId'];
                $this->secret_key = $session_credentials['SecretAccessKey'];
                return true;
            }
            // Otherwise set the values to blank and return false.
            else
            {
                throw new CFRuntime_Exception('No valid credentials were used to authenticate with AWS.');
            }
        }
    }

    /**
     * The callback function that is executed  while caching the session credentials.
     *
     * @param string $key (Optional) Your AWS key, or a session key. If blank, it will look for the <code>AWS_KEY</code> constant.
     * @param string $secret_key (Optional) Your AWS secret key, or a session secret key. If blank, it will look for the <code>AWS_SECRET_KEY</code> constant.
     * @return mixed The data to be cached or null.
     */
    public function cache_token($key, $secret_key)
    {
        $token = new AmazonSTS($key, $secret_key);
        $response = $token->get_session_token();

        if ($response->isOK())
        {
            /*
            Array
            (
                [AccessKeyId] => ******
                [Expiration] => ******
                [SecretAccessKey] => ******
                [SessionToken] => ******
            )
            */
            return $response->body->GetSessionTokenResult->Credentials->to_array()->getArrayCopy();
        }

        return null;
    }

    /**
     * Alternate approach to constructing a new instance. Supports chaining.
     *
     * @param string $key (Optional) Your AWS key, or a session key. If blank, it will look for the <code>AWS_KEY</code> constant.
     * @param string $secret_key (Optional) Your AWS secret key, or a session secret key. If blank, it will look for the <code>AWS_SECRET_KEY</code> constant.
     * @param string $token (optional) An AWS session token. If blank, a request will be made to the AWS Secure Token Service to fetch a set of session credentials.
     * @return boolean A value of `false` if no valid values are set, otherwise `true`.
     */
    public static function init($key = null, $secret_key = null, $token = null)
    {
        if (version_compare(PHP_VERSION, '5.3.0', '<'))
        {
            throw new Exception('PHP 5.3 or newer is required to instantiate a new class with CLASS::init().');
        }

        $self = get_called_class();
        return new $self($key, $secret_key, $token);
    }


    /*%******************************************************************************************%*/
    // MAGIC METHODS

    /**
     * A magic method that allows `camelCase` method names to be translated into `snake_case` names.
     *
     * @param string $name (Required) The name of the method.
     * @param array $arguments (Required) The arguments passed to the method.
     * @return mixed The results of the intended method.
     */
    public function  __call($name, $arguments)
    {
        // Convert camelCase method calls to snake_case.
        $method_name = strtolower(preg_replace('/([a-z])([A-Z])/', '$1_$2', $name));

        if (method_exists($this, $method_name))
        {
            return call_user_func_array(array($this, $method_name), $arguments);
        }

        throw new CFRuntime_Exception('The method ' . $name . '() is undefined. Attempted to map to ' . $method_name . '() which is also undefined. Error occurred');
    }


    /*%******************************************************************************************%*/
    // SET CUSTOM SETTINGS

    /**
     * Adjusts the current time. Use this method for occasions when a server is out of sync with Amazon
     * servers.
     *
     * @param integer $seconds (Required) The number of seconds to adjust the sent timestamp by.
     * @return $this A reference to the current instance.
     */
    public function adjust_offset($seconds)
    {
        $this->adjust_offset = $seconds;
        return $this;
    }

    /**
     * Set the proxy settings to use.
     *
     * @param string $proxy (Required) Accepts proxy credentials in the following format: `proxy://user:pass@hostname:port`
     * @return $this A reference to the current instance.
     */
    public function set_proxy($proxy)
    {
        $this->proxy = $proxy;
        return $this;
    }

    /**
     * Set the hostname to connect to. This is useful for alternate services that are API-compatible with
     * AWS, but run from a different hostname.
     *
     * @param string $hostname (Required) The alternate hostname to use in place of the default one. Useful for mock or test applications living on different hostnames.
     * @param integer $port_number (Optional) The alternate port number to use in place of the default one. Useful for mock or test applications living on different port numbers.
     * @return $this A reference to the current instance.
     */
    public function set_hostname($hostname, $port_number = null)
    {
        if ($this->override_hostname)
        {
            $this->hostname = $hostname;

            if ($port_number)
            {
                $this->port_number = $port_number;
                $this->hostname .= ':' . (string) $this->port_number;
            }
        }

        return $this;
    }

    /**
     * Set the resource prefix to use. This method is useful for alternate services that are API-compatible
     * with AWS.
     *
     * @param string $prefix (Required) An alternate prefix to prepend to the resource path. Useful for mock or test applications.
     * @return $this A reference to the current instance.
     */
    public function set_resource_prefix($prefix)
    {
        $this->resource_prefix = $prefix;
        return $this;
    }

    /**
     * Disables any subsequent use of the <set_hostname()> method.
     *
     * @param boolean $override (Optional) Whether or not subsequent calls to <set_hostname()> should be obeyed. A `false` value disables the further effectiveness of <set_hostname()>. Defaults to `true`.
     * @return $this A reference to the current instance.
     */
    public function allow_hostname_override($override = true)
    {
        $this->override_hostname = $override;
        return $this;
    }

    /**
     * Disables SSL/HTTPS connections for hosts that don't support them. Some services, however, still
     * require SSL support.
     *
     * This method will throw a user warning when invoked, which can be hidden by changing your
     * <php:error_reporting()> settings.
     *
     * @return $this A reference to the current instance.
     */
    public function disable_ssl()
    {
        trigger_error('Disabling SSL connections is potentially unsafe and highly discouraged.', E_USER_WARNING);
        $this->use_ssl = false;
        return $this;
    }

    /**
     * Disables the verification of the SSL Certificate Authority. Doing so can enable an attacker to carry
     * out a man-in-the-middle attack.
     *
     * https://secure.wikimedia.org/wikipedia/en/wiki/Man-in-the-middle_attack
     *
     * This method will throw a user warning when invoked, which can be hidden by changing your
     * <php:error_reporting()> settings.
     *
     * @return $this A reference to the current instance.
     */
    public function disable_ssl_verification($ssl_verification = false)
    {
        trigger_error('Disabling the verification of SSL certificates can lead to man-in-the-middle attacks. It is potentially unsafe and highly discouraged.', E_USER_WARNING);
        $this->ssl_verification = $ssl_verification;
        return $this;
    }

    /**
     * Enables HTTP request/response header logging to `STDERR`.
     *
     * @param boolean $enabled (Optional) Whether or not to enable debug mode. Defaults to `true`.
     * @return $this A reference to the current instance.
     */
    public function enable_debug_mode($enabled = true)
    {
        $this->debug_mode = $enabled;
        return $this;
    }

    /**
     * Sets the maximum number of times to retry failed requests.
     *
     * @param integer $retries (Optional) The maximum number of times to retry failed requests. Defaults to `3`.
     * @return $this A reference to the current instance.
     */
    public function set_max_retries($retries = 3)
    {
        $this->max_retries = $retries;
        return $this;
    }

    /**
     * Set the caching configuration to use for response caching.
     *
     * @param string $location (Required) <p>The location to store the cache object in. This may vary by cache method.</p><ul><li>File - The local file system paths such as <code>./cache</code> (relative) or <code>/tmp/cache/</code> (absolute). The location must be server-writable.</li><li>APC - Pass in <code>apc</code> to use this lightweight cache. You must have the <a href="http://php.net/apc">APC extension</a> installed.</li><li>XCache - Pass in <code>xcache</code> to use this lightweight cache. You must have the <a href="http://xcache.lighttpd.net">XCache</a> extension installed.</li><li>Memcached - Pass in an indexed array of associative arrays. Each associative array should have a <code>host</code> and a <code>port</code> value representing a <a href="http://php.net/memcached">Memcached</a> server to connect to.</li><li>PDO - A URL-style string (e.g. <code>pdo.mysql://user:pass@localhost/cache</code>) or a standard DSN-style string (e.g. <code>pdo.sqlite:/sqlite/cache.db</code>). MUST be prefixed with <code>pdo.</code>. See <code>CachePDO</code> and <a href="http://php.net/pdo">PDO</a> for more details.</li></ul>
     * @param boolean $gzip (Optional) Whether or not data should be gzipped before being stored. A value of `true` will compress the contents before caching them. A value of `false` will leave the contents uncompressed. Defaults to `true`.
     * @return $this A reference to the current instance.
     */
    public function set_cache_config($location, $gzip = true)
    {
        // If we have an array, we're probably passing in Memcached servers and ports.
        if (is_array($location))
        {
            $this->cache_class = 'CacheMC';
        }
        else
        {
            // I would expect locations like `/tmp/cache`, `pdo.mysql://user:pass@hostname:port`, `pdo.sqlite:memory:`, and `apc`.
            $type = strtolower(substr($location, 0, 3));
            switch ($type)
            {
                case 'apc':
                    $this->cache_class = 'CacheAPC';
                    break;

                case 'xca': // First three letters of `xcache`
                    $this->cache_class = 'CacheXCache';
                    break;

                case 'pdo':
                    $this->cache_class = 'CachePDO';
                    $location = substr($location, 4);
                    break;

                default:
                    $this->cache_class = 'CacheFile';
                    break;
            }
        }

        // Set the remaining cache information.
        $this->cache_location = $location;
        $this->cache_compress = $gzip;

        return $this;
    }

    /**
     * Register a callback function to execute whenever a data stream is read from using
     * <CFRequest::streaming_read_callback()>.
     *
     * The user-defined callback function should accept three arguments:
     *
     * <ul>
     *     <li><code>$curl_handle</code> - <code>resource</code> - Required - The cURL handle resource that represents the in-progress transfer.</li>
     *     <li><code>$file_handle</code> - <code>resource</code> - Required - The file handle resource that represents the file on the local file system.</li>
     *     <li><code>$length</code> - <code>integer</code> - Required - The length in kilobytes of the data chunk that was transferred.</li>
     * </ul>
     *
     * @param string|array|function $callback (Required) The callback function is called by <php:call_user_func()>, so you can pass the following values: <ul>
     *     <li>The name of a global function to execute, passed as a string.</li>
     *     <li>A method to execute, passed as <code>array('ClassName', 'MethodName')</code>.</li>
     *     <li>An anonymous function (PHP 5.3+).</li></ul>
     * @return $this A reference to the current instance.
     */
    public function register_streaming_read_callback($callback)
    {
        $this->registered_streaming_read_callback = $callback;
        return $this;
    }

    /**
     * Register a callback function to execute whenever a data stream is written to using
     * <CFRequest::streaming_write_callback()>.
     *
     * The user-defined callback function should accept two arguments:
     *
     * <ul>
     *     <li><code>$curl_handle</code> - <code>resource</code> - Required - The cURL handle resource that represents the in-progress transfer.</li>
     *     <li><code>$length</code> - <code>integer</code> - Required - The length in kilobytes of the data chunk that was transferred.</li>
     * </ul>
     *
     * @param string|array|function $callback (Required) The callback function is called by <php:call_user_func()>, so you can pass the following values: <ul>
     *     <li>The name of a global function to execute, passed as a string.</li>
     *     <li>A method to execute, passed as <code>array('ClassName', 'MethodName')</code>.</li>
     *     <li>An anonymous function (PHP 5.3+).</li></ul>
     * @return $this A reference to the current instance.
     */
    public function register_streaming_write_callback($callback)
    {
        $this->registered_streaming_write_callback = $callback;
        return $this;
    }


    /*%******************************************************************************************%*/
    // SET CUSTOM CLASSES

    /**
     * Set a custom class for this functionality. Use this method when extending/overriding existing classes
     * with new functionality.
     *
     * The replacement class must extend from <CFUtilities>.
     *
     * @param string $class (Optional) The name of the new class to use for this functionality.
     * @return $this A reference to the current instance.
     */
    public function set_utilities_class($class = 'CFUtilities')
    {
        $this->utilities_class = $class;
        $this->util = new $this->utilities_class();
        return $this;
    }

    /**
     * Set a custom class for this functionality. Use this method when extending/overriding existing classes
     * with new functionality.
     *
     * The replacement class must extend from <CFRequest>.
     *
     * @param string $class (Optional) The name of the new class to use for this functionality.
     * @param $this A reference to the current instance.
     */
    public function set_request_class($class = 'CFRequest')
    {
        $this->request_class = $class;
        return $this;
    }

    /**
     * Set a custom class for this functionality. Use this method when extending/overriding existing classes
     * with new functionality.
     *
     * The replacement class must extend from <CFResponse>.
     *
     * @param string $class (Optional) The name of the new class to use for this functionality.
     * @return $this A reference to the current instance.
     */
    public function set_response_class($class = 'CFResponse')
    {
        $this->response_class = $class;
        return $this;
    }

    /**
     * Set a custom class for this functionality. Use this method when extending/overriding existing classes
     * with new functionality.
     *
     * The replacement class must extend from <CFSimpleXML>.
     *
     * @param string $class (Optional) The name of the new class to use for this functionality.
     * @return $this A reference to the current instance.
     */
    public function set_parser_class($class = 'CFSimpleXML')
    {
        $this->parser_class = $class;
        return $this;
    }

    /**
     * Set a custom class for this functionality. Use this method when extending/overriding existing classes
     * with new functionality.
     *
     * The replacement class must extend from <CFBatchRequest>.
     *
     * @param string $class (Optional) The name of the new class to use for this functionality.
     * @return $this A reference to the current instance.
     */
    public function set_batch_class($class = 'CFBatchRequest')
    {
        $this->batch_class = $class;
        return $this;
    }


    /*%******************************************************************************************%*/
    // AUTHENTICATION

    /**
     * Default, shared method for authenticating a connection to AWS. Overridden on a class-by-class basis
     * as necessary.
     *
     * @param string $action (Required) Indicates the action to perform.
     * @param array $opt (Optional) An associative array of parameters for authenticating. See the individual methods for allowed keys.
     * @param string $domain (Optional) The URL of the queue to perform the action on.
     * @param integer $signature_version (Optional) The signature version to use. Defaults to 2.
     * @param integer $redirects (Do Not Use) Used internally by this function on occasions when Amazon S3 returns a redirect code and it needs to call itself recursively.
     * @return CFResponse Object containing a parsed HTTP response.
     */
    public function authenticate($action, $opt = null, $domain = null, $signature_version = 2, $redirects = 0)
    {
        // Handle nulls
        if (is_null($signature_version))
        {
            $signature_version = 2;
        }

        $method_arguments = func_get_args();
        $headers = array();
        $signed_headers = array();

        // Use the caching flow to determine if we need to do a round-trip to the server.
        if ($this->use_cache_flow)
        {
            // Generate an identifier specific to this particular set of arguments.
            $cache_id = $this->key . '_' . get_class($this) . '_' . $action . '_' . sha1(serialize($method_arguments));

            // Instantiate the appropriate caching object.
            $this->cache_object = new $this->cache_class($cache_id, $this->cache_location, $this->cache_expires, $this->cache_compress);

            if ($this->delete_cache)
            {
                $this->use_cache_flow = false;
                $this->delete_cache = false;
                return $this->cache_object->delete();
            }

            // Invoke the cache callback function to determine whether to pull data from the cache or make a fresh request.
            $data = $this->cache_object->response_manager(array($this, 'cache_callback'), $method_arguments);

            // Parse the XML body
            $data = $this->parse_callback($data);

            // End!
            return $data;
        }

        $return_curl_handle = false;
        $x_amz_target = null;

        // Do we have a custom resource prefix?
        if ($this->resource_prefix)
        {
            $domain .= $this->resource_prefix;
        }

        // Determine signing values
        $current_time = time() + $this->adjust_offset;
        $date = gmdate(CFUtilities::DATE_FORMAT_RFC2616, $current_time);
        $timestamp = gmdate(CFUtilities::DATE_FORMAT_ISO8601, $current_time);
        $nonce = $this->util->generate_guid();

        // Do we have an authentication token?
        if ($this->auth_token)
        {
            $headers['X-Amz-Security-Token'] = $this->auth_token;
            $query['SecurityToken'] = $this->auth_token;
        }

        // Manage the key-value pairs that are used in the query.
        if (stripos($action, 'x-amz-target') !== false)
        {
            $x_amz_target = trim(str_ireplace('x-amz-target:', '', $action));
        }
        else
        {
            $query['Action'] = $action;
        }

        // Only add it if it exists.
        if ($this->api_version)
        {
            $query['Version'] = $this->api_version;
        }

        // Only Signature v2
        if ($signature_version === 2)
        {
            $query['AWSAccessKeyId'] = $this->key;
            $query['SignatureMethod'] = 'HmacSHA256';
            $query['SignatureVersion'] = 2;
            $query['Timestamp'] = $timestamp;
        }

        $curlopts = array();

        // Set custom CURLOPT settings
        if (is_array($opt) && isset($opt['curlopts']))
        {
            $curlopts = $opt['curlopts'];
            unset($opt['curlopts']);
        }

        // Merge in any options that were passed in
        if (is_array($opt))
        {
            $query = array_merge($query, $opt);
        }

        $return_curl_handle = isset($query['returnCurlHandle']) ? $query['returnCurlHandle'] : false;
        unset($query['returnCurlHandle']);

        // Do a case-sensitive, natural order sort on the array keys.
        uksort($query, 'strcmp');

        // Normalize JSON input
        if (isset($query['body']) && $query['body'] === '[]')
        {
            $query['body'] = '{}';
        }

        if ($this->use_aws_query)
        {
            // Create the string that needs to be hashed.
            $canonical_query_string = $this->util->to_signable_string($query);
        }
        else
        {
            // Create the string that needs to be hashed.
            $canonical_query_string = $this->util->encode_signature2($query['body']);
        }

        // Remove the default scheme from the domain.
        $domain = str_replace(array('http://', 'https://'), '', $domain);

        // Parse our request.
        $parsed_url = parse_url('http://' . $domain);

        // Set the proper host header.
        if (isset($parsed_url['port']) && (integer) $parsed_url['port'] !== 80 && (integer) $parsed_url['port'] !== 443)
        {
            $host_header = strtolower($parsed_url['host']) . ':' . $parsed_url['port'];
        }
        else
        {
            $host_header = strtolower($parsed_url['host']);
        }

        // Set the proper request URI.
        $request_uri = isset($parsed_url['path']) ? $parsed_url['path'] : '/';

        if ($signature_version === 2)
        {
            // Prepare the string to sign
            $string_to_sign = "POST\n$host_header\n$request_uri\n$canonical_query_string";

            // Hash the AWS secret key and generate a signature for the request.
            $query['Signature'] = base64_encode(hash_hmac('sha256', $string_to_sign, $this->secret_key, true));
        }

        // Generate the querystring from $query
        $querystring = $this->util->to_query_string($query);

        // Gather information to pass along to other classes.
        $helpers = array(
            'utilities' => $this->utilities_class,
            'request' => $this->request_class,
            'response' => $this->response_class,
        );

        // Compose the request.
        $request_url = ($this->use_ssl ? 'https://' : 'http://') . $domain;
        $request_url .= !isset($parsed_url['path']) ? '/' : '';

        // Instantiate the request class
        $request = new $this->request_class($request_url, $this->proxy, $helpers);
        $request->set_method('POST');
        $request->set_body($querystring);
        $headers['Content-Type'] = 'application/x-www-form-urlencoded; charset=utf-8';

        // Signing using X-Amz-Target is handled differently.
        if ($signature_version === 3 && $x_amz_target)
        {
            $headers['X-Amz-Target'] = $x_amz_target;
            $headers['Content-Type'] = 'application/json; amzn-1.0';
            $headers['Content-Encoding'] = 'amz-1.0';

            $request->set_body($query['body']);
            $querystring = $query['body'];
        }

        // Pass along registered stream callbacks
        if ($this->registered_streaming_read_callback)
        {
            $request->register_streaming_read_callback($this->registered_streaming_read_callback);
        }

        if ($this->registered_streaming_write_callback)
        {
            $request->register_streaming_write_callback($this->registered_streaming_write_callback);
        }

        // Add authentication headers
        if ($signature_version === 3)
        {
            $headers['X-Amz-Nonce'] = $nonce;
            $headers['Date'] = $date;
            $headers['Content-Length'] = strlen($querystring);
            $headers['Content-MD5'] = $this->util->hex_to_base64(md5($querystring));
            $headers['Host'] = $host_header;
        }

        // Sort headers
        uksort($headers, 'strnatcasecmp');

        if ($signature_version === 3 && $this->use_ssl)
        {
            // Prepare the string to sign (HTTPS)
            $string_to_sign = $date . $nonce;
        }
        elseif ($signature_version === 3 && !$this->use_ssl)
        {
            // Prepare the string to sign (HTTP)
            $string_to_sign = "POST\n$request_uri\n\n";
        }

        // Add headers to request and compute the string to sign
        foreach ($headers as $header_key => $header_value)
        {
            // Strip linebreaks from header values as they're illegal and can allow for security issues
            $header_value = str_replace(array("\r", "\n"), '', $header_value);

            // Add the header if it has a value
            if ($header_value !== '')
            {
                $request->add_header($header_key, $header_value);
            }

            // Signature v3 over HTTP
            if ($signature_version === 3 && !$this->use_ssl)
            {
                // Generate the string to sign
                if (
                    substr(strtolower($header_key), 0, 8) === 'content-' ||
                    strtolower($header_key) === 'date' ||
                    strtolower($header_key) === 'expires' ||
                    strtolower($header_key) === 'host' ||
                    substr(strtolower($header_key), 0, 6) === 'x-amz-'
                )
                {
                    $string_to_sign .= strtolower($header_key) . ':' . $header_value . "\n";
                    $signed_headers[] = $header_key;
                }
            }
        }

        if ($signature_version === 3)
        {
            if (!$this->use_ssl)
            {
                $string_to_sign .= "\n";

                if (isset($query['body']) && $query['body'] !== '')
                {
                    $string_to_sign .= $query['body'];
                }

                // Convert from string-to-sign to bytes-to-sign
                $bytes_to_sign = hash('sha256', $string_to_sign, true);

                // Hash the AWS secret key and generate a signature for the request.
                $signature = base64_encode(hash_hmac('sha256', $bytes_to_sign, $this->secret_key, true));
            }
            else
            {
                // Hash the AWS secret key and generate a signature for the request.
                $signature = base64_encode(hash_hmac('sha256', $string_to_sign, $this->secret_key, true));
            }

            $headers['X-Amzn-Authorization'] = 'AWS3' . ($this->use_ssl ? '-HTTPS' : '')
                . ' AWSAccessKeyId=' . $this->key
                . ',Algorithm=HmacSHA256'
                . ',SignedHeaders=' . implode(';', $signed_headers)
                . ',Signature=' . $signature;

            $request->add_header('X-Amzn-Authorization', $headers['X-Amzn-Authorization']);
        }

        // Update RequestCore settings
        $request->request_class = $this->request_class;
        $request->response_class = $this->response_class;
        $request->ssl_verification = $this->ssl_verification;

        // Debug mode
        if ($this->debug_mode)
        {
            $request->debug_mode = $this->debug_mode;
        }

        if (count($curlopts))
        {
            $request->set_curlopts($curlopts);
        }

        // Manage the (newer) batch request API or the (older) returnCurlHandle setting.
        if ($this->use_batch_flow)
        {
            $handle = $request->prep_request();
            $this->batch_object->add($handle);
            $this->use_batch_flow = false;

            return $handle;
        }
        elseif ($return_curl_handle)
        {
            return $request->prep_request();
        }

        // Send!
        $request->send_request();

        $request_headers = $headers;

        // Prepare the response.
        $headers = $request->get_response_header();
        $headers['x-aws-stringtosign'] = $string_to_sign;
        $headers['x-aws-request-headers'] = $request_headers;
        $headers['x-aws-body'] = $querystring;

        $data = new $this->response_class($headers, $this->parse_callback($request->get_response_body(), $headers), $request->get_response_code());

        // Was it Amazon's fault the request failed? Retry the request until we reach $max_retries.
        if ((integer) $request->get_response_code() === 500 || (integer) $request->get_response_code() === 503)
        {
            if ($redirects <= $this->max_retries)
            {
                // Exponential backoff
                $delay = (integer) (pow(4, $redirects) * 100000);
                usleep($delay);
                $data = $this->authenticate($action, $opt, $domain, $signature_version, ++$redirects);
            }
        }

        return $data;
    }


    /*%******************************************************************************************%*/
    // BATCH REQUEST LAYER

    /**
     * Specifies that the intended request should be queued for a later batch request.
     *
     * @param CFBatchRequest $queue (Optional) The <CFBatchRequest> instance to use for managing batch requests. If not available, it generates a new instance of <CFBatchRequest>.
     * @return $this A reference to the current instance.
     */
    public function batch(CFBatchRequest &$queue = null)
    {
        if ($queue)
        {
            $this->batch_object = $queue;
        }
        elseif ($this->internal_batch_object)
        {
            $this->batch_object = &$this->internal_batch_object;
        }
        else
        {
            $this->internal_batch_object = new $this->batch_class();
            $this->batch_object = &$this->internal_batch_object;
        }

        $this->use_batch_flow = true;

        return $this;
    }

    /**
     * Executes the batch request queue by sending all queued requests.
     *
     * @param boolean $clear_after_send (Optional) Whether or not to clear the batch queue after sending a request. Defaults to `true`. Set this to `false` if you are caching batch responses and want to retrieve results later.
     * @return array An array of <CFResponse> objects.
     */
    public function send($clear_after_send = true)
    {
        if ($this->use_batch_flow)
        {
            // When we send the request, disable batch flow.
            $this->use_batch_flow = false;

            // If we're not caching, simply send the request.
            if (!$this->use_cache_flow)
            {
                $response = $this->batch_object->send();
                $parsed_data = array_map(array($this, 'parse_callback'), $response);
                $parsed_data = new CFArray($parsed_data);

                // Clear the queue
                if ($clear_after_send)
                {
                    $this->batch_object->queue = array();
                }

                return $parsed_data;
            }

            // Generate an identifier specific to this particular set of arguments.
            $cache_id = $this->key . '_' . get_class($this) . '_' . sha1(serialize($this->batch_object));

            // Instantiate the appropriate caching object.
            $this->cache_object = new $this->cache_class($cache_id, $this->cache_location, $this->cache_expires, $this->cache_compress);

            if ($this->delete_cache)
            {
                $this->use_cache_flow = false;
                $this->delete_cache = false;
                return $this->cache_object->delete();
            }

            // Invoke the cache callback function to determine whether to pull data from the cache or make a fresh request.
            $data_set = $this->cache_object->response_manager(array($this, 'cache_callback_batch'), array($this->batch_object));
            $parsed_data = array_map(array($this, 'parse_callback'), $data_set);
            $parsed_data = new CFArray($parsed_data);

            // Clear the queue
            if ($clear_after_send)
            {
                $this->batch_object->queue = array();
            }

            // End!
            return $parsed_data;
        }

        // Load the class
        $null = new CFBatchRequest();
        unset($null);

        throw new CFBatchRequest_Exception('You must use $object->batch()->send()');
    }

    /**
     * Parses a response body into a PHP object if appropriate.
     *
     * @param CFResponse|string $response (Required) The <CFResponse> object to parse, or an XML string that would otherwise be a response body.
     * @param string $content_type (Optional) The content-type to use when determining how to parse the content.
     * @return CFResponse|string A parsed <CFResponse> object, or parsed XML.
     */
    public function parse_callback($response, $headers = null)
    {
        // Shorten this so we have a (mostly) single code path
        if (isset($response->body))
        {
            if (is_string($response->body))
            {
                $body = $response->body;
            }
            else
            {
                return $response;
            }
        }
        elseif (is_string($response))
        {
            $body = $response;
        }
        else
        {
            return $response;
        }

        // Decompress gzipped content
        if (isset($headers['content-encoding']))
        {
            switch (strtolower(trim($headers['content-encoding'], "\x09\x0A\x0D\x20")))
            {
                case 'gzip':
                case 'x-gzip':
                    if (strpos($headers['_info']['url'], 'monitoring.') !== false)
                    {
                        // CloudWatch incorrectly uses the deflate algorithm when they say gzip.
                        if (($uncompressed = gzuncompress($body)) !== false)
                        {
                            $body = $uncompressed;
                        }
                        elseif (($uncompressed = gzinflate($body)) !== false)
                        {
                            $body = $uncompressed;
                        }
                        break;
                    }
                    else
                    {
                        // Everyone else uses gzip correctly.
                        $decoder = new CFGzipDecode($body);
                        if ($decoder->parse())
                        {
                            $body = $decoder->data;
                        }
                        break;
                    }

                case 'deflate':
                    if (strpos($headers['_info']['url'], 'monitoring.') !== false)
                    {
                        // CloudWatchWatch incorrectly does nothing when they say deflate.
                        continue;
                    }
                    else
                    {
                        // Everyone else uses deflate correctly.
                        if (($uncompressed = gzuncompress($body)) !== false)
                        {
                            $body = $uncompressed;
                        }
                        elseif (($uncompressed = gzinflate($body)) !== false)
                        {
                            $body = $uncompressed;
                        }
                    }
                    break;
            }
        }

        // Look for XML cues
        if (
            (isset($headers['content-type']) && ($headers['content-type'] === 'text/xml' || $headers['content-type'] === 'application/xml')) || // We know it's XML
            (!isset($headers['content-type']) && (stripos($body, '<?xml') === 0 || strpos($body, '<Error>') === 0) || preg_match('/^<(\w*) xmlns="http(s?):\/\/(\w*).amazon(aws)?.com/im', $body)) // Sniff for XML
        )
        {
            // Strip the default XML namespace to simplify XPath expressions
            $body = str_replace("xmlns=", "ns=", $body);

            // Parse the XML body
            $body = new $this->parser_class($body);
        }
        // Look for JSON cues
        elseif (
            (isset($headers['content-type']) && $headers['content-type'] === 'application/json') || // We know it's JSON
            (!isset($headers['content-type']) && $this->util->is_json($body)) // Sniff for JSON
        )
        {
            // Normalize JSON to a CFSimpleXML object
            $body = CFJSON::to_xml($body);
        }

        // Put the parsed data back where it goes
        if (isset($response->body))
        {
            $response->body = $body;
        }
        else
        {
            $response = $body;
        }

        return $response;
    }


    /*%******************************************************************************************%*/
    // CACHING LAYER

    /**
     * Specifies that the resulting <CFResponse> object should be cached according to the settings from
     * <set_cache_config()>.
     *
     * @param string|integer $expires (Required) The time the cache is to expire. Accepts a number of seconds as an integer, or an amount of time, as a string, that is understood by <php:strtotime()> (e.g. "1 hour").
     * @param $this A reference to the current instance.
     * @return $this
     */
    public function cache($expires)
    {
        // Die if they haven't used set_cache_config().
        if (!$this->cache_class)
        {
            throw new CFRuntime_Exception('Must call set_cache_config() before using cache()');
        }

        if (is_string($expires))
        {
            $expires = strtotime($expires);
            $this->cache_expires = $expires - time();
        }
        elseif (is_int($expires))
        {
            $this->cache_expires = $expires;
        }

        $this->use_cache_flow = true;

        return $this;
    }

    /**
     * The callback function that is executed when the cache doesn't exist or has expired. The response of
     * this method is cached. Accepts identical parameters as the <authenticate()> method. Never call this
     * method directly -- it is used internally by the caching system.
     *
     * @param string $action (Required) Indicates the action to perform.
     * @param array $opt (Optional) An associative array of parameters for authenticating. See the individual methods for allowed keys.
     * @param string $domain (Optional) The URL of the queue to perform the action on.
     * @param integer $signature_version (Optional) The signature version to use. Defaults to 2.
     * @return CFResponse A parsed HTTP response.
     */
    public function cache_callback($action, $opt = null, $domain = null, $signature_version = 2)
    {
        // Disable the cache flow since it's already been handled.
        $this->use_cache_flow = false;

        // Make the request
        $response = $this->authenticate($action, $opt, $domain, $signature_version);

        // If this is an XML document, convert it back to a string.
        if (isset($response->body) && ($response->body instanceof SimpleXMLElement))
        {
            $response->body = $response->body->asXML();
        }

        return $response;
    }

    /**
     * Used for caching the results of a batch request. Never call this method directly; it is used
     * internally by the caching system.
     *
     * @param CFBatchRequest $batch (Required) The batch request object to send.
     * @return CFResponse A parsed HTTP response.
     */
    public function cache_callback_batch(CFBatchRequest $batch)
    {
        return $batch->send();
    }

    /**
     * Deletes a cached <CFResponse> object using the specified cache storage type.
     *
     * @return boolean A value of `true` if cached object exists and is successfully deleted, otherwise `false`.
     */
    public function delete_cache()
    {
        $this->use_cache_flow = true;
        $this->delete_cache = true;

        return $this;
    }
}


/**
 * Contains the functionality for auto-loading service classes.
 */
class CFLoader
{

    /*%******************************************************************************************%*/
    // AUTO-LOADER

    /**
     * Automatically load classes that aren't included.
     *
     * @param string $class (Required) The classname to load.
     * @return void
     */
    public static function autoloader($class)
    {
        $path = dirname(__FILE__) . DIRECTORY_SEPARATOR;

        // Amazon SDK classes
        if (strstr($class, 'Amazon'))
        {
            $path .= 'services' . DIRECTORY_SEPARATOR . str_ireplace('Amazon', '', strtolower($class)) . '.class.php';
        }

        // Utility classes
        elseif (strstr($class, 'CF'))
        {
            $path .= 'utilities' . DIRECTORY_SEPARATOR . str_ireplace('CF', '', strtolower($class)) . '.class.php';
        }

        // Load CacheCore
        elseif (strstr($class, 'Cache'))
        {
            if (file_exists($ipath = 'lib' . DIRECTORY_SEPARATOR . 'cachecore' . DIRECTORY_SEPARATOR . 'icachecore.interface.php'))
            {
                require_once($ipath);
            }

            $path .= 'lib' . DIRECTORY_SEPARATOR . 'cachecore' . DIRECTORY_SEPARATOR . strtolower($class) . '.class.php';
        }

        // Load RequestCore
        elseif (strstr($class, 'RequestCore') || strstr($class, 'ResponseCore'))
        {
            $path .= 'lib' . DIRECTORY_SEPARATOR . 'requestcore' . DIRECTORY_SEPARATOR . 'requestcore.class.php';
        }

        // Load Symfony YAML classes
        elseif (strstr($class, 'sfYaml'))
        {
            $path .= 'lib' . DIRECTORY_SEPARATOR . 'yaml' . DIRECTORY_SEPARATOR . 'lib' . DIRECTORY_SEPARATOR . 'sfYaml.php';
        }

        // Fall back to the 'extensions' directory.
        elseif (defined('AWS_ENABLE_EXTENSIONS') && AWS_ENABLE_EXTENSIONS)
        {
            $path .= 'extensions' . DIRECTORY_SEPARATOR . strtolower($class) . '.class.php';
        }

        if (file_exists($path) && !is_dir($path))
        {
            require_once($path);
        }
    }
}

// Register the autoloader.
spl_autoload_register(array('CFLoader', 'autoloader'));