source: trunk/plugins/S3.php @ 15512

<?php
/**
* $Id$
*
* Copyright (c) 2011, Donovan Schönknecht.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
*   this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
*   notice, this list of conditions and the following disclaimer in the
*   documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Amazon S3 is a trademark of Amazon.com, Inc. or its affiliates.
*/

/**
* Amazon S3 PHP class
*
* @link http://undesigned.org.za/2007/10/22/amazon-s3-php-class
* @version 0.5.0-dev
*/
class S3
{
    // ACL flags
    const ACL_PRIVATE = 'private';
    const ACL_PUBLIC_READ = 'public-read';
    const ACL_PUBLIC_READ_WRITE = 'public-read-write';
    const ACL_AUTHENTICATED_READ = 'authenticated-read';

    const STORAGE_CLASS_STANDARD = 'STANDARD';
    const STORAGE_CLASS_RRS = 'REDUCED_REDUNDANCY';

    private static $__accessKey = null; // AWS Access key
    private static $__secretKey = null; // AWS Secret key
    private static $__sslKey = null;

    public static $endpoint = 's3.amazonaws.com';
    public static $proxy = null;

    public static $useSSL = false;
    public static $useSSLValidation = true;
    public static $useExceptions = false;

    // SSL CURL SSL options - only needed if you are experiencing problems with your OpenSSL configuration
    public static $sslKey = null;
    public static $sslCert = null;
    public static $sslCACert = null;

    private static $__signingKeyPairId = null; // AWS Key Pair ID
    private static $__signingKeyResource = false; // Key resource, freeSigningKey() must be called to clear it from memory


    /**
    * Constructor - if you're not using the class statically
    *
    * @param string $accessKey Access key
    * @param string $secretKey Secret key
    * @param boolean $useSSL Enable SSL
    * @return void
    */
    public function __construct($accessKey = null, $secretKey = null, $useSSL = false, $endpoint = 's3.amazonaws.com')
    {
        if ($accessKey !== null && $secretKey !== null)
            self::setAuth($accessKey, $secretKey);
        self::$useSSL = $useSSL;
        self::$endpoint = $endpoint;
    }


    /**
    * Set the sertvice endpoint
    *
    * @param string $host Hostname
    * @return void
    */
    public function setEndpoint($host)
    {
        self::$endpoint = $host;
    }

    /**
    * Set AWS access key and secret key
    *
    * @param string $accessKey Access key
    * @param string $secretKey Secret key
    * @return void
    */
    public static function setAuth($accessKey, $secretKey)
    {
        self::$__accessKey = $accessKey;
        self::$__secretKey = $secretKey;
    }


    /**
    * Check if AWS keys have been set
    *
    * @return boolean
    */
    public static function hasAuth() {
        return (self::$__accessKey !== null && self::$__secretKey !== null);
    }


    /**
    * Set SSL on or off
    *
    * @param boolean $enabled SSL enabled
    * @param boolean $validate SSL certificate validation
    * @return void
    */
    public static function setSSL($enabled, $validate = true)
    {
        self::$useSSL = $enabled;
        self::$useSSLValidation = $validate;
    }


    /**
    * Set SSL client certificates (experimental)
    *
    * @param string $sslCert SSL client certificate
    * @param string $sslKey SSL client key
    * @param string $sslCACert SSL CA cert (only required if you are having problems with your system CA cert)
    * @return void
    */
    public static function setSSLAuth($sslCert = null, $sslKey = null, $sslCACert = null)
    {
        self::$sslCert = $sslCert;
        self::$sslKey = $sslKey;
        self::$sslCACert = $sslCACert;
    }


    /**
    * Set proxy information
    *
    * @param string $host Proxy hostname and port (localhost:1234)
    * @param string $user Proxy username
    * @param string $pass Proxy password
    * @param constant $type CURL proxy type
    * @return void
    */
    public static function setProxy($host, $user = null, $pass = null, $type = CURLPROXY_SOCKS5)
    {
        self::$proxy = array('host' => $host, 'type' => $type, 'user' => null, 'pass' => 'null');
    }


    /**
    * Set the error mode to exceptions
    *
    * @param boolean $enabled Enable exceptions
    * @return void
    */
    public static function setExceptions($enabled = true)
    {
        self::$useExceptions = $enabled;
    }


    /**
    * Set signing key
    *
    * @param string $keyPairId AWS Key Pair ID
    * @param string $signingKey Private Key
    * @param boolean $isFile Load private key from file, set to false to load string
    * @return boolean
    */
    public static function setSigningKey($keyPairId, $signingKey, $isFile = true)
    {
        self::$__signingKeyPairId = $keyPairId;
        if ((self::$__signingKeyResource = openssl_pkey_get_private($isFile ?
        file_get_contents($signingKey) : $signingKey)) !== false) return true;
        self::__triggerError('S3::setSigningKey(): Unable to open load private key: '.$signingKey, __FILE__, __LINE__);
        return false;
    }


    /**
    * Free signing key from memory, MUST be called if you are using setSigningKey()
    *
    * @return void
    */
    public static function freeSigningKey()
    {
        if (self::$__signingKeyResource !== false)
            openssl_free_key(self::$__signingKeyResource);
    }


    /**
    * Internal error handler
    *
    * @internal Internal error handler
    * @param string $message Error message
    * @param string $file Filename
    * @param integer $line Line number
    * @param integer $code Error code
    * @return void
    */
    private static function __triggerError($message, $file, $line, $code = 0)
    {
        if (self::$useExceptions)
            throw new S3Exception($message, $file, $line, $code);
        else
            trigger_error($message, E_USER_WARNING);
    }


    /**
    * Get a list of buckets
    *
    * @param boolean $detailed Returns detailed bucket list when true
    * @return array | false
    */
    public static function listBuckets($detailed = false)
    {
        $rest = new S3Request('GET', '', '', self::$endpoint);
        $rest = $rest->getResponse();
        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::listBuckets(): [%s] %s", $rest->error['code'],
            $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        $results = array();
        if (!isset($rest->body->Buckets)) return $results;

        if ($detailed)
        {
            if (isset($rest->body->Owner, $rest->body->Owner->ID, $rest->body->Owner->DisplayName))
            $results['owner'] = array(
                'id' => (string)$rest->body->Owner->ID, 'name' => (string)$rest->body->Owner->ID
            );
            $results['buckets'] = array();
            foreach ($rest->body->Buckets->Bucket as $b)
                $results['buckets'][] = array(
                    'name' => (string)$b->Name, 'time' => strtotime((string)$b->CreationDate)
                );
        } else
            foreach ($rest->body->Buckets->Bucket as $b) $results[] = (string)$b->Name;

        return $results;
    }


    /*
    * Get contents for a bucket
    *
    * If maxKeys is null this method will loop through truncated result sets
    *
    * @param string $bucket Bucket name
    * @param string $prefix Prefix
    * @param string $marker Marker (last file listed)
    * @param string $maxKeys Max keys (maximum number of keys to return)
    * @param string $delimiter Delimiter
    * @param boolean $returnCommonPrefixes Set to true to return CommonPrefixes
    * @return array | false
    */
    public static function getBucket($bucket, $prefix = null, $marker = null, $maxKeys = null, $delimiter = null, $returnCommonPrefixes = false)
    {
        $rest = new S3Request('GET', $bucket, '', self::$endpoint);
        if ($maxKeys == 0) $maxKeys = null;
        if ($prefix !== null && $prefix !== '') $rest->setParameter('prefix', $prefix);
        if ($marker !== null && $marker !== '') $rest->setParameter('marker', $marker);
        if ($maxKeys !== null && $maxKeys !== '') $rest->setParameter('max-keys', $maxKeys);
        if ($delimiter !== null && $delimiter !== '') $rest->setParameter('delimiter', $delimiter);
        $response = $rest->getResponse();
        if ($response->error === false && $response->code !== 200)
            $response->error = array('code' => $response->code, 'message' => 'Unexpected HTTP status');
        if ($response->error !== false)
        {
            self::__triggerError(sprintf("S3::getBucket(): [%s] %s",
            $response->error['code'], $response->error['message']), __FILE__, __LINE__);
            return false;
        }

        $results = array();

        $nextMarker = null;
        if (isset($response->body, $response->body->Contents))
        foreach ($response->body->Contents as $c)
        {
            $results[(string)$c->Key] = array(
                'name' => (string)$c->Key,
                'time' => strtotime((string)$c->LastModified),
                'size' => (int)$c->Size,
                'hash' => substr((string)$c->ETag, 1, -1)
            );
            $nextMarker = (string)$c->Key;
        }

        if ($returnCommonPrefixes && isset($response->body, $response->body->CommonPrefixes))
            foreach ($response->body->CommonPrefixes as $c)
                $results[(string)$c->Prefix] = array('prefix' => (string)$c->Prefix);

        if (isset($response->body, $response->body->IsTruncated) &&
        (string)$response->body->IsTruncated == 'false') return $results;

        if (isset($response->body, $response->body->NextMarker))
            $nextMarker = (string)$response->body->NextMarker;

        // Loop through truncated results if maxKeys isn't specified
        if ($maxKeys == null && $nextMarker !== null && (string)$response->body->IsTruncated == 'true')
        do
        {
            $rest = new S3Request('GET', $bucket, '', self::$endpoint);
            if ($prefix !== null && $prefix !== '') $rest->setParameter('prefix', $prefix);
            $rest->setParameter('marker', $nextMarker);
            if ($delimiter !== null && $delimiter !== '') $rest->setParameter('delimiter', $delimiter);

            if (($response = $rest->getResponse(true)) == false || $response->code !== 200) break;

            if (isset($response->body, $response->body->Contents))
            foreach ($response->body->Contents as $c)
            {
                $results[(string)$c->Key] = array(
                    'name' => (string)$c->Key,
                    'time' => strtotime((string)$c->LastModified),
                    'size' => (int)$c->Size,
                    'hash' => substr((string)$c->ETag, 1, -1)
                );
                $nextMarker = (string)$c->Key;
            }

            if ($returnCommonPrefixes && isset($response->body, $response->body->CommonPrefixes))
                foreach ($response->body->CommonPrefixes as $c)
                    $results[(string)$c->Prefix] = array('prefix' => (string)$c->Prefix);

            if (isset($response->body, $response->body->NextMarker))
                $nextMarker = (string)$response->body->NextMarker;

        } while ($response !== false && (string)$response->body->IsTruncated == 'true');

        return $results;
    }


    /**
    * Put a bucket
    *
    * @param string $bucket Bucket name
    * @param constant $acl ACL flag
    * @param string $location Set as "EU" to create buckets hosted in Europe
    * @return boolean
    */
    public static function putBucket($bucket, $acl = self::ACL_PRIVATE, $location = false)
    {
        $rest = new S3Request('PUT', $bucket, '', self::$endpoint);
        $rest->setAmzHeader('x-amz-acl', $acl);

        if ($location !== false)
        {
            $dom = new DOMDocument;
            $createBucketConfiguration = $dom->createElement('CreateBucketConfiguration');
            $locationConstraint = $dom->createElement('LocationConstraint', strtoupper($location));
            $createBucketConfiguration->appendChild($locationConstraint);
            $dom->appendChild($createBucketConfiguration);
            $rest->data = $dom->saveXML();
            $rest->size = strlen($rest->data);
            $rest->setHeader('Content-Type', 'application/xml');
        }
        $rest = $rest->getResponse();

        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::putBucket({$bucket}, {$acl}, {$location}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        return true;
    }


    /**
    * Delete an empty bucket
    *
    * @param string $bucket Bucket name
    * @return boolean
    */
    public static function deleteBucket($bucket)
    {
        $rest = new S3Request('DELETE', $bucket, '', self::$endpoint);
        $rest = $rest->getResponse();
        if ($rest->error === false && $rest->code !== 204)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::deleteBucket({$bucket}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        return true;
    }


    /**
    * Create input info array for putObject()
    *
    * @param string $file Input file
    * @param mixed $md5sum Use MD5 hash (supply a string if you want to use your own)
    * @return array | false
    */
    public static function inputFile($file, $md5sum = true)
    {
        if (!file_exists($file) || !is_file($file) || !is_readable($file))
        {
            self::__triggerError('S3::inputFile(): Unable to open input file: '.$file, __FILE__, __LINE__);
            return false;
        }
        clearstatcache(true, $file);
        return array('file' => $file, 'size' => filesize($file), 'md5sum' => $md5sum !== false ?
        (is_string($md5sum) ? $md5sum : base64_encode(md5_file($file, true))) : '');
    }


    /**
    * Create input array info for putObject() with a resource
    *
    * @param string $resource Input resource to read from
    * @param integer $bufferSize Input byte size
    * @param string $md5sum MD5 hash to send (optional)
    * @return array | false
    */
    public static function inputResource(&$resource, $bufferSize, $md5sum = '')
    {
        if (!is_resource($resource) || $bufferSize < 0)
        {
            self::__triggerError('S3::inputResource(): Invalid resource or buffer size', __FILE__, __LINE__);
            return false;
        }
        $input = array('size' => $bufferSize, 'md5sum' => $md5sum);
        $input['fp'] =& $resource;
        return $input;
    }


    /**
    * Put an object
    *
    * @param mixed $input Input data
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @param constant $acl ACL constant
    * @param array $metaHeaders Array of x-amz-meta-* headers
    * @param array $requestHeaders Array of request headers or content type as a string
    * @param constant $storageClass Storage class constant
    * @return boolean
    */
    public static function putObject($input, $bucket, $uri, $acl = self::ACL_PRIVATE, $metaHeaders = array(), $requestHeaders = array(), $storageClass = self::STORAGE_CLASS_STANDARD)
    {
        if ($input === false) return false;
        $rest = new S3Request('PUT', $bucket, $uri, self::$endpoint);

        if (is_string($input)) $input = array(
            'data' => $input, 'size' => strlen($input),
            'md5sum' => base64_encode(md5($input, true))
        );

        // Data
        if (isset($input['fp']))
            $rest->fp =& $input['fp'];
        elseif (isset($input['file']))
            $rest->fp = @fopen($input['file'], 'rb');
        elseif (isset($input['data']))
            $rest->data = $input['data'];

        // Content-Length (required)
        if (isset($input['size']) && $input['size'] >= 0)
            $rest->size = $input['size'];
        else {
            if (isset($input['file']))
                $rest->size = filesize($input['file']);
            elseif (isset($input['data']))
                $rest->size = strlen($input['data']);
        }

        // Custom request headers (Content-Type, Content-Disposition, Content-Encoding)
        if (is_array($requestHeaders))
            foreach ($requestHeaders as $h => $v) $rest->setHeader($h, $v);
        elseif (is_string($requestHeaders)) // Support for legacy contentType parameter
            $input['type'] = $requestHeaders;

        // Content-Type
        if (!isset($input['type']))
        {
            if (isset($requestHeaders['Content-Type']))
                $input['type'] =& $requestHeaders['Content-Type'];
            elseif (isset($input['file']))
                $input['type'] = self::__getMimeType($input['file']);
            else
                $input['type'] = 'application/octet-stream';
        }

        if ($storageClass !== self::STORAGE_CLASS_STANDARD) // Storage class
            $rest->setAmzHeader('x-amz-storage-class', $storageClass);

        // We need to post with Content-Length and Content-Type, MD5 is optional
        if ($rest->size >= 0 && ($rest->fp !== false || $rest->data !== false))
        {
            $rest->setHeader('Content-Type', $input['type']);
            if (isset($input['md5sum'])) $rest->setHeader('Content-MD5', $input['md5sum']);

            $rest->setAmzHeader('x-amz-acl', $acl);
            foreach ($metaHeaders as $h => $v) $rest->setAmzHeader('x-amz-meta-'.$h, $v);
            $rest->getResponse();
        } else
            $rest->response->error = array('code' => 0, 'message' => 'Missing input parameters');

        if ($rest->response->error === false && $rest->response->code !== 200)
            $rest->response->error = array('code' => $rest->response->code, 'message' => 'Unexpected HTTP status');
        if ($rest->response->error !== false)
        {
            self::__triggerError(sprintf("S3::putObject(): [%s] %s",
            $rest->response->error['code'], $rest->response->error['message']), __FILE__, __LINE__);
            return false;
        }
        return true;
    }


    /**
    * Put an object from a file (legacy function)
    *
    * @param string $file Input file path
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @param constant $acl ACL constant
    * @param array $metaHeaders Array of x-amz-meta-* headers
    * @param string $contentType Content type
    * @return boolean
    */
    public static function putObjectFile($file, $bucket, $uri, $acl = self::ACL_PRIVATE, $metaHeaders = array(), $contentType = null)
    {
        return self::putObject(self::inputFile($file), $bucket, $uri, $acl, $metaHeaders, $contentType);
    }


    /**
    * Put an object from a string (legacy function)
    *
    * @param string $string Input data
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @param constant $acl ACL constant
    * @param array $metaHeaders Array of x-amz-meta-* headers
    * @param string $contentType Content type
    * @return boolean
    */
    public static function putObjectString($string, $bucket, $uri, $acl = self::ACL_PRIVATE, $metaHeaders = array(), $contentType = 'text/plain')
    {
        return self::putObject($string, $bucket, $uri, $acl, $metaHeaders, $contentType);
    }


    /**
    * Get an object
    *
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @param mixed $saveTo Filename or resource to write to
    * @return mixed
    */
    public static function getObject($bucket, $uri, $saveTo = false)
    {
        $rest = new S3Request('GET', $bucket, $uri, self::$endpoint);
        if ($saveTo !== false)
        {
            if (is_resource($saveTo))
                $rest->fp =& $saveTo;
            else
                if (($rest->fp = @fopen($saveTo, 'wb')) !== false)
                    $rest->file = realpath($saveTo);
                else
                    $rest->response->error = array('code' => 0, 'message' => 'Unable to open save file for writing: '.$saveTo);
        }
        if ($rest->response->error === false) $rest->getResponse();

        if ($rest->response->error === false && $rest->response->code !== 200)
            $rest->response->error = array('code' => $rest->response->code, 'message' => 'Unexpected HTTP status');
        if ($rest->response->error !== false)
        {
            self::__triggerError(sprintf("S3::getObject({$bucket}, {$uri}): [%s] %s",
            $rest->response->error['code'], $rest->response->error['message']), __FILE__, __LINE__);
            return false;
        }
        return $rest->response;
    }


    /**
    * Get object information
    *
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @param boolean $returnInfo Return response information
    * @return mixed | false
    */
    public static function getObjectInfo($bucket, $uri, $returnInfo = true)
    {
        $rest = new S3Request('HEAD', $bucket, $uri, self::$endpoint);
        $rest = $rest->getResponse();
        if ($rest->error === false && ($rest->code !== 200 && $rest->code !== 404))
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::getObjectInfo({$bucket}, {$uri}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        return $rest->code == 200 ? $returnInfo ? $rest->headers : true : false;
    }


    /**
    * Copy an object
    *
    * @param string $bucket Source bucket name
    * @param string $uri Source object URI
    * @param string $bucket Destination bucket name
    * @param string $uri Destination object URI
    * @param constant $acl ACL constant
    * @param array $metaHeaders Optional array of x-amz-meta-* headers
    * @param array $requestHeaders Optional array of request headers (content type, disposition, etc.)
    * @param constant $storageClass Storage class constant
    * @return mixed | false
    */
    public static function copyObject($srcBucket, $srcUri, $bucket, $uri, $acl = self::ACL_PRIVATE, $metaHeaders = array(), $requestHeaders = array(), $storageClass = self::STORAGE_CLASS_STANDARD)
    {
        $rest = new S3Request('PUT', $bucket, $uri, self::$endpoint);
        $rest->setHeader('Content-Length', 0);
        foreach ($requestHeaders as $h => $v) $rest->setHeader($h, $v);
        foreach ($metaHeaders as $h => $v) $rest->setAmzHeader('x-amz-meta-'.$h, $v);
        if ($storageClass !== self::STORAGE_CLASS_STANDARD) // Storage class
            $rest->setAmzHeader('x-amz-storage-class', $storageClass);
        $rest->setAmzHeader('x-amz-acl', $acl); // Added rawurlencode() for $srcUri (thanks a.yamanoi)
        $rest->setAmzHeader('x-amz-copy-source', sprintf('/%s/%s', $srcBucket, rawurlencode($srcUri)));
        if (sizeof($requestHeaders) > 0 || sizeof($metaHeaders) > 0)
            $rest->setAmzHeader('x-amz-metadata-directive', 'REPLACE');

        $rest = $rest->getResponse();
        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::copyObject({$srcBucket}, {$srcUri}, {$bucket}, {$uri}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        return isset($rest->body->LastModified, $rest->body->ETag) ? array(
            'time' => strtotime((string)$rest->body->LastModified),
            'hash' => substr((string)$rest->body->ETag, 1, -1)
        ) : false;
    }


    /**
    * Set logging for a bucket
    *
    * @param string $bucket Bucket name
    * @param string $targetBucket Target bucket (where logs are stored)
    * @param string $targetPrefix Log prefix (e,g; domain.com-)
    * @return boolean
    */
    public static function setBucketLogging($bucket, $targetBucket, $targetPrefix = null)
    {
        // The S3 log delivery group has to be added to the target bucket's ACP
        if ($targetBucket !== null && ($acp = self::getAccessControlPolicy($targetBucket, '')) !== false)
        {
            // Only add permissions to the target bucket when they do not exist
            $aclWriteSet = false;
            $aclReadSet = false;
            foreach ($acp['acl'] as $acl)
            if ($acl['type'] == 'Group' && $acl['uri'] == 'http://acs.amazonaws.com/groups/s3/LogDelivery')
            {
                if ($acl['permission'] == 'WRITE') $aclWriteSet = true;
                elseif ($acl['permission'] == 'READ_ACP') $aclReadSet = true;
            }
            if (!$aclWriteSet) $acp['acl'][] = array(
                'type' => 'Group', 'uri' => 'http://acs.amazonaws.com/groups/s3/LogDelivery', 'permission' => 'WRITE'
            );
            if (!$aclReadSet) $acp['acl'][] = array(
                'type' => 'Group', 'uri' => 'http://acs.amazonaws.com/groups/s3/LogDelivery', 'permission' => 'READ_ACP'
            );
            if (!$aclReadSet || !$aclWriteSet) self::setAccessControlPolicy($targetBucket, '', $acp);
        }

        $dom = new DOMDocument;
        $bucketLoggingStatus = $dom->createElement('BucketLoggingStatus');
        $bucketLoggingStatus->setAttribute('xmlns', 'http://s3.amazonaws.com/doc/2006-03-01/');
        if ($targetBucket !== null)
        {
            if ($targetPrefix == null) $targetPrefix = $bucket . '-';
            $loggingEnabled = $dom->createElement('LoggingEnabled');
            $loggingEnabled->appendChild($dom->createElement('TargetBucket', $targetBucket));
            $loggingEnabled->appendChild($dom->createElement('TargetPrefix', $targetPrefix));
            // TODO: Add TargetGrants?
            $bucketLoggingStatus->appendChild($loggingEnabled);
        }
        $dom->appendChild($bucketLoggingStatus);

        $rest = new S3Request('PUT', $bucket, '', self::$endpoint);
        $rest->setParameter('logging', null);
        $rest->data = $dom->saveXML();
        $rest->size = strlen($rest->data);
        $rest->setHeader('Content-Type', 'application/xml');
        $rest = $rest->getResponse();
        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::setBucketLogging({$bucket}, {$uri}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        return true;
    }


    /**
    * Get logging status for a bucket
    *
    * This will return false if logging is not enabled.
    * Note: To enable logging, you also need to grant write access to the log group
    *
    * @param string $bucket Bucket name
    * @return array | false
    */
    public static function getBucketLogging($bucket)
    {
        $rest = new S3Request('GET', $bucket, '', self::$endpoint);
        $rest->setParameter('logging', null);
        $rest = $rest->getResponse();
        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::getBucketLogging({$bucket}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        if (!isset($rest->body->LoggingEnabled)) return false; // No logging
        return array(
            'targetBucket' => (string)$rest->body->LoggingEnabled->TargetBucket,
            'targetPrefix' => (string)$rest->body->LoggingEnabled->TargetPrefix,
        );
    }


    /**
    * Disable bucket logging
    *
    * @param string $bucket Bucket name
    * @return boolean
    */
    public static function disableBucketLogging($bucket)
    {
        return self::setBucketLogging($bucket, null);
    }


    /**
    * Get a bucket's location
    *
    * @param string $bucket Bucket name
    * @return string | false
    */
    public static function getBucketLocation($bucket)
    {
        $rest = new S3Request('GET', $bucket, '', self::$endpoint);
        $rest->setParameter('location', null);
        $rest = $rest->getResponse();
        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::getBucketLocation({$bucket}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        return (isset($rest->body[0]) && (string)$rest->body[0] !== '') ? (string)$rest->body[0] : 'US';
    }


    /**
    * Set object or bucket Access Control Policy
    *
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @param array $acp Access Control Policy Data (same as the data returned from getAccessControlPolicy)
    * @return boolean
    */
    public static function setAccessControlPolicy($bucket, $uri = '', $acp = array())
    {
        $dom = new DOMDocument;
        $dom->formatOutput = true;
        $accessControlPolicy = $dom->createElement('AccessControlPolicy');
        $accessControlList = $dom->createElement('AccessControlList');

        // It seems the owner has to be passed along too
        $owner = $dom->createElement('Owner');
        $owner->appendChild($dom->createElement('ID', $acp['owner']['id']));
        $owner->appendChild($dom->createElement('DisplayName', $acp['owner']['name']));
        $accessControlPolicy->appendChild($owner);

        foreach ($acp['acl'] as $g)
        {
            $grant = $dom->createElement('Grant');
            $grantee = $dom->createElement('Grantee');
            $grantee->setAttribute('xmlns:xsi', 'http://www.w3.org/2001/XMLSchema-instance');
            if (isset($g['id']))
            { // CanonicalUser (DisplayName is omitted)
                $grantee->setAttribute('xsi:type', 'CanonicalUser');
                $grantee->appendChild($dom->createElement('ID', $g['id']));
            }
            elseif (isset($g['email']))
            { // AmazonCustomerByEmail
                $grantee->setAttribute('xsi:type', 'AmazonCustomerByEmail');
                $grantee->appendChild($dom->createElement('EmailAddress', $g['email']));
            }
            elseif ($g['type'] == 'Group')
            { // Group
                $grantee->setAttribute('xsi:type', 'Group');
                $grantee->appendChild($dom->createElement('URI', $g['uri']));
            }
            $grant->appendChild($grantee);
            $grant->appendChild($dom->createElement('Permission', $g['permission']));
            $accessControlList->appendChild($grant);
        }

        $accessControlPolicy->appendChild($accessControlList);
        $dom->appendChild($accessControlPolicy);

        $rest = new S3Request('PUT', $bucket, $uri, self::$endpoint);
        $rest->setParameter('acl', null);
        $rest->data = $dom->saveXML();
        $rest->size = strlen($rest->data);
        $rest->setHeader('Content-Type', 'application/xml');
        $rest = $rest->getResponse();
        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::setAccessControlPolicy({$bucket}, {$uri}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        return true;
    }


    /**
    * Get object or bucket Access Control Policy
    *
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @return mixed | false
    */
    public static function getAccessControlPolicy($bucket, $uri = '')
    {
        $rest = new S3Request('GET', $bucket, $uri, self::$endpoint);
        $rest->setParameter('acl', null);
        $rest = $rest->getResponse();
        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::getAccessControlPolicy({$bucket}, {$uri}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }

        $acp = array();
        if (isset($rest->body->Owner, $rest->body->Owner->ID, $rest->body->Owner->DisplayName))
            $acp['owner'] = array(
                'id' => (string)$rest->body->Owner->ID, 'name' => (string)$rest->body->Owner->DisplayName
            );

        if (isset($rest->body->AccessControlList))
        {
            $acp['acl'] = array();
            foreach ($rest->body->AccessControlList->Grant as $grant)
            {
                foreach ($grant->Grantee as $grantee)
                {
                    if (isset($grantee->ID, $grantee->DisplayName)) // CanonicalUser
                        $acp['acl'][] = array(
                            'type' => 'CanonicalUser',
                            'id' => (string)$grantee->ID,
                            'name' => (string)$grantee->DisplayName,
                            'permission' => (string)$grant->Permission
                        );
                    elseif (isset($grantee->EmailAddress)) // AmazonCustomerByEmail
                        $acp['acl'][] = array(
                            'type' => 'AmazonCustomerByEmail',
                            'email' => (string)$grantee->EmailAddress,
                            'permission' => (string)$grant->Permission
                        );
                    elseif (isset($grantee->URI)) // Group
                        $acp['acl'][] = array(
                            'type' => 'Group',
                            'uri' => (string)$grantee->URI,
                            'permission' => (string)$grant->Permission
                        );
                    else continue;
                }
            }
        }
        return $acp;
    }


    /**
    * Delete an object
    *
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @return boolean
    */
    public static function deleteObject($bucket, $uri)
    {
        $rest = new S3Request('DELETE', $bucket, $uri, self::$endpoint);
        $rest = $rest->getResponse();
        if ($rest->error === false && $rest->code !== 204)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::deleteObject(): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        return true;
    }


    /**
    * Get a query string authenticated URL
    *
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @param integer $lifetime Lifetime in seconds
    * @param boolean $hostBucket Use the bucket name as the hostname
    * @param boolean $https Use HTTPS ($hostBucket should be false for SSL verification)
    * @return string
    */
    public static function getAuthenticatedURL($bucket, $uri, $lifetime, $hostBucket = false, $https = false)
    {
        $expires = time() + $lifetime;
        $uri = str_replace('%2F', '/', rawurlencode($uri)); // URI should be encoded (thanks Sean O'Dea)
        return sprintf(($https ? 'https' : 'http').'://%s/%s?AWSAccessKeyId=%s&Expires=%u&Signature=%s',
        $hostBucket ? $bucket : $bucket.'.s3.amazonaws.com', $uri, self::$__accessKey, $expires,
        urlencode(self::__getHash("GET\n\n\n{$expires}\n/{$bucket}/{$uri}")));
    }


    /**
    * Get a CloudFront signed policy URL
    *
    * @param array $policy Policy
    * @return string
    */
    public static function getSignedPolicyURL($policy)
    {
        $data = json_encode($policy);
        $signature = '';
        if (!openssl_sign($data, $signature, self::$__signingKeyResource)) return false;

        $encoded = str_replace(array('+', '='), array('-', '_', '~'), base64_encode($data));
        $signature = str_replace(array('+', '='), array('-', '_', '~'), base64_encode($signature));

        $url = $policy['Statement'][0]['Resource'] . '?';

        foreach (array('Policy' => $encoded, 'Signature' => $signature, 'Key-Pair-Id' => self::$__signingKeyPairId) as $k => $v)
            $url .= $k.'='.str_replace('%2F', '/', rawurlencode($v)).'&';
        return substr($url, 0, -1);
    }


    /**
    * Get a CloudFront canned policy URL
    *
    * @param string $string URL to sign
    * @param integer $lifetime URL lifetime
    * @return string
    */
    public static function getSignedCannedURL($url, $lifetime)
    {
        return self::getSignedPolicyURL(array(
            'Statement' => array(
                array('Resource' => $url, 'Condition' => array(
                    'DateLessThan' => array('AWS:EpochTime' => time() + $lifetime)
                ))
            )
        ));
    }


    /**
    * Get upload POST parameters for form uploads
    *
    * @param string $bucket Bucket name
    * @param string $uriPrefix Object URI prefix
    * @param constant $acl ACL constant
    * @param integer $lifetime Lifetime in seconds
    * @param integer $maxFileSize Maximum filesize in bytes (default 5MB)
    * @param string $successRedirect Redirect URL or 200 / 201 status code
    * @param array $amzHeaders Array of x-amz-meta-* headers
    * @param array $headers Array of request headers or content type as a string
    * @param boolean $flashVars Includes additional "Filename" variable posted by Flash
    * @return object
    */
    public static function getHttpUploadPostParams($bucket, $uriPrefix = '', $acl = self::ACL_PRIVATE, $lifetime = 3600,
    $maxFileSize = 5242880, $successRedirect = "201", $amzHeaders = array(), $headers = array(), $flashVars = false)
    {
        // Create policy object
        $policy = new stdClass;
        $policy->expiration = gmdate('Y-m-d\TH:i:s\Z', (time() + $lifetime));
        $policy->conditions = array();
        $obj = new stdClass; $obj->bucket = $bucket; array_push($policy->conditions, $obj);
        $obj = new stdClass; $obj->acl = $acl; array_push($policy->conditions, $obj);

        $obj = new stdClass; // 200 for non-redirect uploads
        if (is_numeric($successRedirect) && in_array((int)$successRedirect, array(200, 201)))
            $obj->success_action_status = (string)$successRedirect;
        else // URL
            $obj->success_action_redirect = $successRedirect;
        array_push($policy->conditions, $obj);

        if ($acl !== self::ACL_PUBLIC_READ)
            array_push($policy->conditions, array('eq', '$acl', $acl));

        array_push($policy->conditions, array('starts-with', '$key', $uriPrefix));
        if ($flashVars) array_push($policy->conditions, array('starts-with', '$Filename', ''));
        foreach (array_keys($headers) as $headerKey)
            array_push($policy->conditions, array('starts-with', '$'.$headerKey, ''));
        foreach ($amzHeaders as $headerKey => $headerVal)
        {
            $obj = new stdClass;
            $obj->{$headerKey} = (string)$headerVal;
            array_push($policy->conditions, $obj);
        }
        array_push($policy->conditions, array('content-length-range', 0, $maxFileSize));
        $policy = base64_encode(str_replace('\/', '/', json_encode($policy)));

        // Create parameters
        $params = new stdClass;
        $params->AWSAccessKeyId = self::$__accessKey;
        $params->key = $uriPrefix.'${filename}';
        $params->acl = $acl;
        $params->policy = $policy; unset($policy);
        $params->signature = self::__getHash($params->policy);
        if (is_numeric($successRedirect) && in_array((int)$successRedirect, array(200, 201)))
            $params->success_action_status = (string)$successRedirect;
        else
            $params->success_action_redirect = $successRedirect;
        foreach ($headers as $headerKey => $headerVal) $params->{$headerKey} = (string)$headerVal;
        foreach ($amzHeaders as $headerKey => $headerVal) $params->{$headerKey} = (string)$headerVal;
        return $params;
    }


    /**
    * Create a CloudFront distribution
    *
    * @param string $bucket Bucket name
    * @param boolean $enabled Enabled (true/false)
    * @param array $cnames Array containing CNAME aliases
    * @param string $comment Use the bucket name as the hostname
    * @param string $defaultRootObject Default root object
    * @param string $originAccessIdentity Origin access identity
    * @param array $trustedSigners Array of trusted signers
    * @return array | false
    */
    public static function createDistribution($bucket, $enabled = true, $cnames = array(), $comment = null, $defaultRootObject = null, $originAccessIdentity = null, $trustedSigners = array())
    {
        if (!extension_loaded('openssl'))
        {
            self::__triggerError(sprintf("S3::createDistribution({$bucket}, ".(int)$enabled.", [], '$comment'): %s",
            "CloudFront functionality requires SSL"), __FILE__, __LINE__);
            return false;
        }
        $useSSL = self::$useSSL;

        self::$useSSL = true; // CloudFront requires SSL
        $rest = new S3Request('POST', '', '2010-11-01/distribution', 'cloudfront.amazonaws.com');
        $rest->data = self::__getCloudFrontDistributionConfigXML(
            $bucket.'.s3.amazonaws.com',
            $enabled,
            (string)$comment,
            (string)microtime(true),
            $cnames,
            $defaultRootObject,
            $originAccessIdentity,
            $trustedSigners
        );

        $rest->size = strlen($rest->data);
        $rest->setHeader('Content-Type', 'application/xml');
        $rest = self::__getCloudFrontResponse($rest);

        self::$useSSL = $useSSL;

        if ($rest->error === false && $rest->code !== 201)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::createDistribution({$bucket}, ".(int)$enabled.", [], '$comment'): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        } elseif ($rest->body instanceof SimpleXMLElement)
            return self::__parseCloudFrontDistributionConfig($rest->body);
        return false;
    }


    /**
    * Get CloudFront distribution info
    *
    * @param string $distributionId Distribution ID from listDistributions()
    * @return array | false
    */
    public static function getDistribution($distributionId)
    {
        if (!extension_loaded('openssl'))
        {
            self::__triggerError(sprintf("S3::getDistribution($distributionId): %s",
            "CloudFront functionality requires SSL"), __FILE__, __LINE__);
            return false;
        }
        $useSSL = self::$useSSL;

        self::$useSSL = true; // CloudFront requires SSL
        $rest = new S3Request('GET', '', '2010-11-01/distribution/'.$distributionId, 'cloudfront.amazonaws.com');
        $rest = self::__getCloudFrontResponse($rest);

        self::$useSSL = $useSSL;

        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::getDistribution($distributionId): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        elseif ($rest->body instanceof SimpleXMLElement)
        {
            $dist = self::__parseCloudFrontDistributionConfig($rest->body);
            $dist['hash'] = $rest->headers['hash'];
            $dist['id'] = $distributionId;
            return $dist;
        }
        return false;
    }


    /**
    * Update a CloudFront distribution
    *
    * @param array $dist Distribution array info identical to output of getDistribution()
    * @return array | false
    */
    public static function updateDistribution($dist)
    {
        if (!extension_loaded('openssl'))
        {
            self::__triggerError(sprintf("S3::updateDistribution({$dist['id']}): %s",
            "CloudFront functionality requires SSL"), __FILE__, __LINE__);
            return false;
        }

        $useSSL = self::$useSSL;

        self::$useSSL = true; // CloudFront requires SSL
        $rest = new S3Request('PUT', '', '2010-11-01/distribution/'.$dist['id'].'/config', 'cloudfront.amazonaws.com');
        $rest->data = self::__getCloudFrontDistributionConfigXML(
            $dist['origin'],
            $dist['enabled'],
            $dist['comment'],
            $dist['callerReference'],
            $dist['cnames'],
            $dist['defaultRootObject'],
            $dist['originAccessIdentity'],
            $dist['trustedSigners']
        );

        $rest->size = strlen($rest->data);
        $rest->setHeader('If-Match', $dist['hash']);
        $rest = self::__getCloudFrontResponse($rest);

        self::$useSSL = $useSSL;

        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::updateDistribution({$dist['id']}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        } else {
            $dist = self::__parseCloudFrontDistributionConfig($rest->body);
            $dist['hash'] = $rest->headers['hash'];
            return $dist;
        }
        return false;
    }


    /**
    * Delete a CloudFront distribution
    *
    * @param array $dist Distribution array info identical to output of getDistribution()
    * @return boolean
    */
    public static function deleteDistribution($dist)
    {
        if (!extension_loaded('openssl'))
        {
            self::__triggerError(sprintf("S3::deleteDistribution({$dist['id']}): %s",
            "CloudFront functionality requires SSL"), __FILE__, __LINE__);
            return false;
        }

        $useSSL = self::$useSSL;

        self::$useSSL = true; // CloudFront requires SSL
        $rest = new S3Request('DELETE', '', '2008-06-30/distribution/'.$dist['id'], 'cloudfront.amazonaws.com');
        $rest->setHeader('If-Match', $dist['hash']);
        $rest = self::__getCloudFrontResponse($rest);

        self::$useSSL = $useSSL;

        if ($rest->error === false && $rest->code !== 204)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::deleteDistribution({$dist['id']}): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        return true;
    }


    /**
    * Get a list of CloudFront distributions
    *
    * @return array
    */
    public static function listDistributions()
    {
        if (!extension_loaded('openssl'))
        {
            self::__triggerError(sprintf("S3::listDistributions(): [%s] %s",
            "CloudFront functionality requires SSL"), __FILE__, __LINE__);
            return false;
        }

        $useSSL = self::$useSSL;
        self::$useSSL = true; // CloudFront requires SSL
        $rest = new S3Request('GET', '', '2010-11-01/distribution', 'cloudfront.amazonaws.com');
        $rest = self::__getCloudFrontResponse($rest);
        self::$useSSL = $useSSL;

        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            self::__triggerError(sprintf("S3::listDistributions(): [%s] %s",
            $rest->error['code'], $rest->error['message']), __FILE__, __LINE__);
            return false;
        }
        elseif ($rest->body instanceof SimpleXMLElement && isset($rest->body->DistributionSummary))
        {
            $list = array();
            if (isset($rest->body->Marker, $rest->body->MaxItems, $rest->body->IsTruncated))
            {
                //$info['marker'] = (string)$rest->body->Marker;
                //$info['maxItems'] = (int)$rest->body->MaxItems;
                //$info['isTruncated'] = (string)$rest->body->IsTruncated == 'true' ? true : false;
            }
            foreach ($rest->body->DistributionSummary as $summary)
                $list[(string)$summary->Id] = self::__parseCloudFrontDistributionConfig($summary);

            return $list;
        }
        return array();
    }

    /**
    * List CloudFront Origin Access Identities
    *
    * @return array
    */
    public static function listOriginAccessIdentities()
    {
        if (!extension_loaded('openssl'))
        {
            self::__triggerError(sprintf("S3::listOriginAccessIdentities(): [%s] %s",
            "CloudFront functionality requires SSL"), __FILE__, __LINE__);
            return false;
        }

        self::$useSSL = true; // CloudFront requires SSL
        $rest = new S3Request('GET', '', '2010-11-01/origin-access-identity/cloudfront', 'cloudfront.amazonaws.com');
        $rest = self::__getCloudFrontResponse($rest);
        $useSSL = self::$useSSL;

        if ($rest->error === false && $rest->code !== 200)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            trigger_error(sprintf("S3::listOriginAccessIdentities(): [%s] %s",
            $rest->error['code'], $rest->error['message']), E_USER_WARNING);
            return false;
        }

        if (isset($rest->body->CloudFrontOriginAccessIdentitySummary))
        {
            $identities = array();
            foreach ($rest->body->CloudFrontOriginAccessIdentitySummary as $identity)
                if (isset($identity->S3CanonicalUserId))
                    $identities[(string)$identity->Id] = array('id' => (string)$identity->Id, 's3CanonicalUserId' => (string)$identity->S3CanonicalUserId);
            return $identities;
        }
        return false;
    }


    /**
    * Invalidate objects in a CloudFront distribution
    *
    * Thanks to Martin Lindkvist for S3::invalidateDistribution()
    *
    * @param string $distributionId Distribution ID from listDistributions()
    * @param array $paths Array of object paths to invalidate
    * @return boolean
    */
    public static function invalidateDistribution($distributionId, $paths)
    {
        if (!extension_loaded('openssl'))
        {
            self::__triggerError(sprintf("S3::invalidateDistribution(): [%s] %s",
            "CloudFront functionality requires SSL"), __FILE__, __LINE__);
            return false;
        }

        $useSSL = self::$useSSL;
        self::$useSSL = true; // CloudFront requires SSL
        $rest = new S3Request('POST', '', '2010-08-01/distribution/'.$distributionId.'/invalidation', 'cloudfront.amazonaws.com');
        $rest->data = self::__getCloudFrontInvalidationBatchXML($paths, (string)microtime(true));
        $rest->size = strlen($rest->data);
        $rest = self::__getCloudFrontResponse($rest);
        self::$useSSL = $useSSL;

        if ($rest->error === false && $rest->code !== 201)
            $rest->error = array('code' => $rest->code, 'message' => 'Unexpected HTTP status');
        if ($rest->error !== false)
        {
            trigger_error(sprintf("S3::invalidate('{$distributionId}',{$paths}): [%s] %s",
            $rest->error['code'], $rest->error['message']), E_USER_WARNING);
            return false;
        }
        return true;
    }


    /**
    * Get a InvalidationBatch DOMDocument
    *
    * @internal Used to create XML in invalidateDistribution()
    * @param array $paths Paths to objects to invalidateDistribution
    * @return string
    */
    private static function __getCloudFrontInvalidationBatchXML($paths, $callerReference = '0') {
        $dom = new DOMDocument('1.0', 'UTF-8');
        $dom->formatOutput = true;
        $invalidationBatch = $dom->createElement('InvalidationBatch');
        foreach ($paths as $path)
            $invalidationBatch->appendChild($dom->createElement('Path', $path));

        $invalidationBatch->appendChild($dom->createElement('CallerReference', $callerReference));
        $dom->appendChild($invalidationBatch);
        return $dom->saveXML();
    }


    /**
    * Get a DistributionConfig DOMDocument
    *
    * http://docs.amazonwebservices.com/AmazonCloudFront/latest/APIReference/index.html?PutConfig.html
    *
    * @internal Used to create XML in createDistribution() and updateDistribution()
    * @param string $bucket S3 Origin bucket
    * @param boolean $enabled Enabled (true/false)
    * @param string $comment Comment to append
    * @param string $callerReference Caller reference
    * @param array $cnames Array of CNAME aliases
    * @param string $defaultRootObject Default root object
    * @param string $originAccessIdentity Origin access identity
    * @param array $trustedSigners Array of trusted signers
    * @return string
    */
    private static function __getCloudFrontDistributionConfigXML($bucket, $enabled, $comment, $callerReference = '0', $cnames = array(), $defaultRootObject = null, $originAccessIdentity = null, $trustedSigners = array())
    {
        $dom = new DOMDocument('1.0', 'UTF-8');
        $dom->formatOutput = true;
        $distributionConfig = $dom->createElement('DistributionConfig');
        $distributionConfig->setAttribute('xmlns', 'http://cloudfront.amazonaws.com/doc/2010-11-01/');

        $origin = $dom->createElement('S3Origin');
        $origin->appendChild($dom->createElement('DNSName', $bucket));
        if ($originAccessIdentity !== null) $origin->appendChild($dom->createElement('OriginAccessIdentity', $originAccessIdentity));
        $distributionConfig->appendChild($origin);

        if ($defaultRootObject !== null) $distributionConfig->appendChild($dom->createElement('DefaultRootObject', $defaultRootObject));

        $distributionConfig->appendChild($dom->createElement('CallerReference', $callerReference));
        foreach ($cnames as $cname)
            $distributionConfig->appendChild($dom->createElement('CNAME', $cname));
        if ($comment !== '') $distributionConfig->appendChild($dom->createElement('Comment', $comment));
        $distributionConfig->appendChild($dom->createElement('Enabled', $enabled ? 'true' : 'false'));

        $trusted = $dom->createElement('TrustedSigners');
        foreach ($trustedSigners as $id => $type)
            $trusted->appendChild($id !== '' ? $dom->createElement($type, $id) : $dom->createElement($type));
        $distributionConfig->appendChild($trusted);

        $dom->appendChild($distributionConfig);
        //var_dump($dom->saveXML());
        return $dom->saveXML();
    }


    /**
    * Parse a CloudFront distribution config
    *
    * See http://docs.amazonwebservices.com/AmazonCloudFront/latest/APIReference/index.html?GetDistribution.html
    *
    * @internal Used to parse the CloudFront DistributionConfig node to an array
    * @param object &$node DOMNode
    * @return array
    */
    private static function __parseCloudFrontDistributionConfig(&$node)
    {
        if (isset($node->DistributionConfig))
            return self::__parseCloudFrontDistributionConfig($node->DistributionConfig);

        $dist = array();
        if (isset($node->Id, $node->Status, $node->LastModifiedTime, $node->DomainName))
        {
            $dist['id'] = (string)$node->Id;
            $dist['status'] = (string)$node->Status;
            $dist['time'] = strtotime((string)$node->LastModifiedTime);
            $dist['domain'] = (string)$node->DomainName;
        }

        if (isset($node->CallerReference))
            $dist['callerReference'] = (string)$node->CallerReference;

        if (isset($node->Enabled))
            $dist['enabled'] = (string)$node->Enabled == 'true' ? true : false;

        if (isset($node->S3Origin))
        {
            if (isset($node->S3Origin->DNSName))
                $dist['origin'] = (string)$node->S3Origin->DNSName;

            $dist['originAccessIdentity'] = isset($node->S3Origin->OriginAccessIdentity) ?
            (string)$node->S3Origin->OriginAccessIdentity : null;
        }

        $dist['defaultRootObject'] = isset($node->DefaultRootObject) ? (string)$node->DefaultRootObject : null;

        $dist['cnames'] = array();
        if (isset($node->CNAME))
            foreach ($node->CNAME as $cname)
                $dist['cnames'][(string)$cname] = (string)$cname;

        $dist['trustedSigners'] = array();
        if (isset($node->TrustedSigners))
            foreach ($node->TrustedSigners as $signer)
            {
                if (isset($signer->Self))
                    $dist['trustedSigners'][''] = 'Self';
                elseif (isset($signer->KeyPairId))
                    $dist['trustedSigners'][(string)$signer->KeyPairId] = 'KeyPairId';
                elseif (isset($signer->AwsAccountNumber))
                    $dist['trustedSigners'][(string)$signer->AwsAccountNumber] = 'AwsAccountNumber';
            }

        $dist['comment'] = isset($node->Comment) ? (string)$node->Comment : null;
        return $dist;
    }


    /**
    * Grab CloudFront response
    *
    * @internal Used to parse the CloudFront S3Request::getResponse() output
    * @param object &$rest S3Request instance
    * @return object
    */
    private static function __getCloudFrontResponse(&$rest)
    {
        $rest->getResponse();
        if ($rest->response->error === false && isset($rest->response->body) &&
        is_string($rest->response->body) && substr($rest->response->body, 0, 5) == '<?xml')
        {
            $rest->response->body = simplexml_load_string($rest->response->body);
            // Grab CloudFront errors
            if (isset($rest->response->body->Error, $rest->response->body->Error->Code,
            $rest->response->body->Error->Message))
            {
                $rest->response->error = array(
                    'code' => (string)$rest->response->body->Error->Code,
                    'message' => (string)$rest->response->body->Error->Message
                );
                unset($rest->response->body);
            }
        }
        return $rest->response;
    }


    /**
    * Get MIME type for file
    *
    * @internal Used to get mime types
    * @param string &$file File path
    * @return string
    */
    public static function __getMimeType(&$file)
    {
        $type = false;
        // Fileinfo documentation says fileinfo_open() will use the
        // MAGIC env var for the magic file
        if (extension_loaded('fileinfo') && isset($_ENV['MAGIC']) &&
        ($finfo = finfo_open(FILEINFO_MIME, $_ENV['MAGIC'])) !== false)
        {
            if (($type = finfo_file($finfo, $file)) !== false)
            {
                // Remove the charset and grab the last content-type
                $type = explode(' ', str_replace('; charset=', ';charset=', $type));
                $type = array_pop($type);
                $type = explode(';', $type);
                $type = trim(array_shift($type));
            }
            finfo_close($finfo);

        // If anyone is still using mime_content_type()
        } elseif (function_exists('mime_content_type'))
            $type = trim(mime_content_type($file));

        if ($type !== false && strlen($type) > 0) return $type;

        // Otherwise do it the old fashioned way
        static $exts = array(
            'jpg' => 'image/jpeg', 'gif' => 'image/gif', 'png' => 'image/png',
            'tif' => 'image/tiff', 'tiff' => 'image/tiff', 'ico' => 'image/x-icon',
            'swf' => 'application/x-shockwave-flash', 'pdf' => 'application/pdf',
            'zip' => 'application/zip', 'gz' => 'application/x-gzip',
            'tar' => 'application/x-tar', 'bz' => 'application/x-bzip',
            'bz2' => 'application/x-bzip2', 'txt' => 'text/plain',
            'asc' => 'text/plain', 'htm' => 'text/html', 'html' => 'text/html',
            'css' => 'text/css', 'js' => 'text/javascript',
            'xml' => 'text/xml', 'xsl' => 'application/xsl+xml',
            'ogg' => 'application/ogg', 'mp3' => 'audio/mpeg', 'wav' => 'audio/x-wav',
            'avi' => 'video/x-msvideo', 'mpg' => 'video/mpeg', 'mpeg' => 'video/mpeg',
            'mov' => 'video/quicktime', 'flv' => 'video/x-flv', 'php' => 'text/x-php'
        );
        $ext = strtolower(pathInfo($file, PATHINFO_EXTENSION));
        return isset($exts[$ext]) ? $exts[$ext] : 'application/octet-stream';
    }


    /**
    * Generate the auth string: "AWS AccessKey:Signature"
    *
    * @internal Used by S3Request::getResponse()
    * @param string $string String to sign
    * @return string
    */
    public static function __getSignature($string)
    {
        return 'AWS '.self::$__accessKey.':'.self::__getHash($string);
    }


    /**
    * Creates a HMAC-SHA1 hash
    *
    * This uses the hash extension if loaded
    *
    * @internal Used by __getSignature()
    * @param string $string String to sign
    * @return string
    */
    private static function __getHash($string)
    {
        return base64_encode(extension_loaded('hash') ?
        hash_hmac('sha1', $string, self::$__secretKey, true) : pack('H*', sha1(
        (str_pad(self::$__secretKey, 64, chr(0x00)) ^ (str_repeat(chr(0x5c), 64))) .
        pack('H*', sha1((str_pad(self::$__secretKey, 64, chr(0x00)) ^
        (str_repeat(chr(0x36), 64))) . $string)))));
    }

}

final class S3Request
{
    private $endpoint, $verb, $bucket, $uri, $resource = '', $parameters = array(),
    $amzHeaders = array(), $headers = array(
        'Host' => '', 'Date' => '', 'Content-MD5' => '', 'Content-Type' => ''
    );
    public $fp = false, $size = 0, $data = false, $response;


    /**
    * Constructor
    *
    * @param string $verb Verb
    * @param string $bucket Bucket name
    * @param string $uri Object URI
    * @return mixed
    */
    function __construct($verb, $bucket = '', $uri = '', $endpoint = 's3.amazonaws.com')
    {
        $this->endpoint = $endpoint;
        $this->verb = $verb;
        $this->bucket = $bucket;
        $this->uri = $uri !== '' ? '/'.str_replace('%2F', '/', rawurlencode($uri)) : '/';

        if ($this->bucket !== '')
        {
            $this->headers['Host'] = $this->bucket.'.'.$this->endpoint;
            $this->resource = '/'.$this->bucket.$this->uri;
        }
        else
        {
            $this->headers['Host'] = $this->endpoint;
            $this->resource = $this->uri;
        }
        $this->headers['Date'] = gmdate('D, d M Y H:i:s T');

        $this->response = new STDClass;
        $this->response->error = false;
    }


    /**
    * Set request parameter
    *
    * @param string $key Key
    * @param string $value Value
    * @return void
    */
    public function setParameter($key, $value)
    {
        $this->parameters[$key] = $value;
    }


    /**
    * Set request header
    *
    * @param string $key Key
    * @param string $value Value
    * @return void
    */
    public function setHeader($key, $value)
    {
        $this->headers[$key] = $value;
    }


    /**
    * Set x-amz-meta-* header
    *
    * @param string $key Key
    * @param string $value Value
    * @return void
    */
    public function setAmzHeader($key, $value)
    {
        $this->amzHeaders[$key] = $value;
    }


    /**
    * Get the S3 response
    *
    * @return object | false
    */
    public function getResponse()
    {
        $query = '';
        if (sizeof($this->parameters) > 0)
        {
            $query = substr($this->uri, -1) !== '?' ? '?' : '&';
            foreach ($this->parameters as $var => $value)
                if ($value == null || $value == '') $query .= $var.'&';
                // Parameters should be encoded (thanks Sean O'Dea)
                else $query .= $var.'='.rawurlencode($value).'&';
            $query = substr($query, 0, -1);
            $this->uri .= $query;

            if (array_key_exists('acl', $this->parameters) ||
            array_key_exists('location', $this->parameters) ||
            array_key_exists('torrent', $this->parameters) ||
            array_key_exists('logging', $this->parameters))
                $this->resource .= $query;
        }
        $url = (S3::$useSSL ? 'https://' : 'http://') . $this->headers['Host'].$this->uri;
        //var_dump($this->bucket, $this->uri, $this->resource, $url);

        // Basic setup
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_USERAGENT, 'S3/php');

        if (S3::$useSSL)
        {
            // SSL Validation can now be optional for those with broken OpenSSL installations
            curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, S3::$useSSLValidation ? 1 : 0);
            curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, S3::$useSSLValidation ? 1 : 0);

            if (S3::$sslKey !== null) curl_setopt($curl, CURLOPT_SSLKEY, S3::$sslKey);
            if (S3::$sslCert !== null) curl_setopt($curl, CURLOPT_SSLCERT, S3::$sslCert);
            if (S3::$sslCACert !== null) curl_setopt($curl, CURLOPT_CAINFO, S3::$sslCACert);
        }

        curl_setopt($curl, CURLOPT_URL, $url);

        if (S3::$proxy != null && isset(S3::$proxy['host']))
        {
            curl_setopt($curl, CURLOPT_PROXY, S3::$proxy['host']);
            curl_setopt($curl, CURLOPT_PROXYTYPE, S3::$proxy['type']);
            if (isset(S3::$proxy['user'], S3::$proxy['pass']) && $proxy['user'] != null && $proxy['pass'] != null)
                curl_setopt($curl, CURLOPT_PROXYUSERPWD, sprintf('%s:%s', S3::$proxy['user'], S3::$proxy['pass']));
        }

        // Headers
        $headers = array(); $amz = array();
        foreach ($this->amzHeaders as $header => $value)
            if (strlen($value) > 0) $headers[] = $header.': '.$value;
        foreach ($this->headers as $header => $value)
            if (strlen($value) > 0) $headers[] = $header.': '.$value;

        // Collect AMZ headers for signature
        foreach ($this->amzHeaders as $header => $value)
            if (strlen($value) > 0) $amz[] = strtolower($header).':'.$value;

        // AMZ headers must be sorted
        if (sizeof($amz) > 0)
        {
            sort($amz);
            $amz = "\n".implode("\n", $amz);
        } else $amz = '';

        if (S3::hasAuth())
        {
            // Authorization string (CloudFront stringToSign should only contain a date)
            $headers[] = 'Authorization: ' . S3::__getSignature(
                $this->headers['Host'] == 'cloudfront.amazonaws.com' ? $this->headers['Date'] :
                $this->verb."\n".$this->headers['Content-MD5']."\n".
                $this->headers['Content-Type']."\n".$this->headers['Date'].$amz."\n".$this->resource
            );
        }

        curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($curl, CURLOPT_HEADER, false);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, false);
        curl_setopt($curl, CURLOPT_WRITEFUNCTION, array(&$this, '__responseWriteCallback'));
        curl_setopt($curl, CURLOPT_HEADERFUNCTION, array(&$this, '__responseHeaderCallback'));
        curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);

        // Request types
        switch ($this->verb)
        {
            case 'GET': break;
            case 'PUT': case 'POST': // POST only used for CloudFront
                if ($this->fp !== false)
                {
                    curl_setopt($curl, CURLOPT_PUT, true);
                    curl_setopt($curl, CURLOPT_INFILE, $this->fp);
                    if ($this->size >= 0)
                        curl_setopt($curl, CURLOPT_INFILESIZE, $this->size);
                }
                elseif ($this->data !== false)
                {
                    curl_setopt($curl, CURLOPT_CUSTOMREQUEST, $this->verb);
                    curl_setopt($curl, CURLOPT_POSTFIELDS, $this->data);
                }
                else
                    curl_setopt($curl, CURLOPT_CUSTOMREQUEST, $this->verb);
            break;
            case 'HEAD':
                curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'HEAD');
                curl_setopt($curl, CURLOPT_NOBODY, true);
            break;
            case 'DELETE':
                curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'DELETE');
            break;
            default: break;
        }

        // Execute, grab errors
        if (curl_exec($curl))
            $this->response->code = curl_getinfo($curl, CURLINFO_HTTP_CODE);
        else
            $this->response->error = array(
                'code' => curl_errno($curl),
                'message' => curl_error($curl),
                'resource' => $this->resource
            );

        @curl_close($curl);

        // Parse body into XML
        if ($this->response->error === false && isset($this->response->headers['type']) &&
        $this->response->headers['type'] == 'application/xml' && isset($this->response->body))
        {
            $this->response->body = simplexml_load_string($this->response->body);

            // Grab S3 errors
            if (!in_array($this->response->code, array(200, 204, 206)) &&
            isset($this->response->body->Code, $this->response->body->Message))
            {
                $this->response->error = array(
                    'code' => (string)$this->response->body->Code,
                    'message' => (string)$this->response->body->Message
                );
                if (isset($this->response->body->Resource))
                    $this->response->error['resource'] = (string)$this->response->body->Resource;
                unset($this->response->body);
            }
        }

        // Clean up file resources
        if ($this->fp !== false && is_resource($this->fp)) fclose($this->fp);

        return $this->response;
    }


    /**
    * CURL write callback
    *
    * @param resource &$curl CURL resource
    * @param string &$data Data
    * @return integer
    */
    private function __responseWriteCallback(&$curl, &$data)
    {
        if (in_array($this->response->code, array(200, 206)) && $this->fp !== false)
            return fwrite($this->fp, $data);
        else
            $this->response->body .= $data;
        return strlen($data);
    }


    /**
    * CURL header callback
    *
    * @param resource &$curl CURL resource
    * @param string &$data Data
    * @return integer
    */
    private function __responseHeaderCallback(&$curl, &$data)
    {
        if (($strlen = strlen($data)) <= 2) return $strlen;
        if (substr($data, 0, 4) == 'HTTP')
            $this->response->code = (int)substr($data, 9, 3);
        else
        {
            $data = trim($data);
            if (strpos($data, ': ') === false) return $strlen;
            list($header, $value) = explode(': ', $data, 2);
            if ($header == 'Last-Modified')
                $this->response->headers['time'] = strtotime($value);
            elseif ($header == 'Content-Length')
                $this->response->headers['size'] = (int)$value;
            elseif ($header == 'Content-Type')
                $this->response->headers['type'] = $value;
            elseif ($header == 'ETag')
                $this->response->headers['hash'] = $value{0} == '"' ? substr($value, 1, -1) : $value;
            elseif (preg_match('/^x-amz-meta-.*$/', $header))
                $this->response->headers[$header] = is_numeric($value) ? (int)$value : $value;
        }
        return $strlen;
    }

}

class S3Exception extends Exception {
    function __construct($message, $file, $line, $code = 0)
    {
        parent::__construct($message, $code);
        $this->file = $file;
        $this->line = $line;
    }
}