modxcms/revolution

<?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.
 */


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

/**
 * Simplifies the process of signing JSON policy documents.
 *
 * @version 2011.04.25
 * @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 CFPolicy
{
    /**
     * Stores the object that contains the authentication credentials.
     */
    public $auth;

    /**
     * Stores the policy object that we're working with.
     */
    public $json_policy;

    /**
     * Constructs a new instance of this class.
     *
     * @param CFRuntime $auth (Required) An instance of any authenticated AWS object that is an instance of <CFRuntime> (e.g. <AmazonEC2>, <AmazonS3>).
     * @param string|array $policy (Required) The associative array representing the S3 policy to use, or a string of JSON content.
     * @return $this A reference to the current instance.
     * @link http://docs.amazonwebservices.com/AmazonS3/2006-03-01/dev/index.html?HTTPPOSTForms.html S3 Policies
     * @link http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?AccessPolicyLanguage.html Access Policy Language
     */
    public function __construct($auth, $policy)
    {
        $this->auth = $auth;

        if (is_array($policy)) // We received an associative array...
        {
            $this->json_policy = json_encode($policy);
        }
        else // We received a valid, parseable JSON string...
        {
            $this->json_policy = json_encode(json_decode($policy, true));
        }

        return $this;
    }

    /**
     * Alternate approach to constructing a new instance. Supports chaining.
     *
     * @param CFRuntime $auth (Required) An instance of any authenticated AWS object that is an instance of <CFRuntime> (e.g. <AmazonEC2>, <AmazonS3>).
     * @param string|array $policy (Required) The associative array representing the S3 policy to use, or a string of JSON content.
     * @return $this A reference to the current instance.
     */
    public static function init($auth, $policy)
    {
        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 $self($auth, $policy);
    }

    /**
     * Get the key from the authenticated instance.
     *
     * @return string The key from the authenticated instance.
     */
    public function get_key()
    {
        return $this->auth->key;
    }

    /**
     * Base64-encodes the JSON string.
     *
     * @return string The Base64-encoded version of the JSON string.
     */
    public function get_policy()
    {
        return base64_encode($this->json_policy);
    }

    /**
     * Gets the JSON string with the whitespace removed.
     *
     * @return string The JSON string without extraneous whitespace.
     */
    public function get_json()
    {
        return $this->json_policy;
    }

    /**
     * Gets the JSON string with the whitespace removed.
     *
     * @return string The Base64-encoded, signed JSON string.
     */
    public function get_policy_signature()
    {
        return base64_encode(hash_hmac('sha1', $this->get_policy(), $this->auth->secret_key));
    }

    /**
     * Decode a policy that was returned from the service.
     *
     * @param string $response (Required) The policy returned by AWS that you want to decode into an object.
     * @return string The Base64-encoded, signed JSON string.
     */
    public static function decode_policy($response)
    {
        return json_decode(urldecode($response), true);
    }
}