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<?php
/**
*
* @copyright Copyright (c) 2020, Lukas Stabe (lukas@stabe.de)
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
namespace OC\Files\ObjectStore;
/**
* A stream wrapper that uses http range requests to provide a seekable
* stream of a file in S3 storage.
*/
class S3SeekableReadStream {
private static $registered = false;
/**
* Registers the stream wrapper using the `s3seek://` url scheme
* $return void
*/
public static function registerIfNeeded() {
if (!self::$registered) {
stream_wrapper_register(
's3seek',
'OC\Files\ObjectStore\S3SeekableReadStream'
);
self::$registered = true;
}
}
private $client;
private $bucket;
private $urn;
private $current;
private $offset = 0;
private function reconnect($range) {
if ($this->current != null) {
fclose($this->current);
}
$command = $this->client->getCommand('GetObject', [
'Bucket' => $this->bucket,
'Key' => $this->urn,
'Range' => 'bytes=' . $range,
]);
$request = \Aws\serialize($command);
$headers = [];
foreach ($request->getHeaders() as $key => $values) {
foreach ($values as $value) {
$headers[] = "$key: $value";
}
}
$opts = [
'http' => [
'protocol_version' => 1.1,
'header' => $headers,
],
];
$context = stream_context_create($opts);
$this->current = fopen($request->getUri(), 'r', false, $context);
if ($this->current === false) {return false;}
$responseHead = stream_get_meta_data($this->current)['wrapper_data'];
$contentRange = array_values(array_filter($responseHead, function ($v) {
return preg_match('#^content-range:#i', $v) === 1;
}))[0];
$content = trim(explode(':', $contentRange)[1]);
$range = trim(explode(' ', $content)[1]);
$begin = explode('-', $range)[0];
$this->offset = intval($begin);
return true;
}
function stream_open($path, $mode, $options, &$opened_path) {
$o = stream_context_get_options($this->context)['s3seek'];
$this->bucket = $o['bucket'];
$this->urn = $o['urn'];
$this->client = $o['client'];
return $this->reconnect('0-');
}
function stream_read($count) {
$ret = fread($this->current, $count);
$this->offset += strlen($ret);
return $ret;
}
function stream_seek($offset, $whence) {
switch ($whence) {
case SEEK_SET:
if ($offset === $this->offset) {return true;}
return $this->reconnect($offset . '-');
case SEEK_CUR:
if ($offset === 0) {return true;}
return $this->reconnect(($this->offset + $offset) . '-');
case SEEK_END:
return false;
}
return false;
}
function stream_tell() {
return $this->offset;
}
function stream_stat() {
return fstat($this->current);
}
function stream_eof() {
return feof($this->current);
}
function stream_close() {
fclose($this->current);
}
}
|
