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- <?php
- /**
- * @copyright Copyright (c) 2020, Lukas Stabe (lukas@stabe.de)
- *
- * @author Lukas Stabe <lukas@stabe.de>
- * @author Robin Appelman <robin@icewind.nl>
- *
- * @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\Stream;
-
- use Icewind\Streams\File;
-
- /**
- * A stream wrapper that uses http range requests to provide a seekable stream for http reading
- */
- class SeekableHttpStream implements File {
- private const PROTOCOL = 'httpseek';
-
- private static $registered = false;
-
- /**
- * Registers the stream wrapper using the `httpseek://` url scheme
- * $return void
- */
- private static function registerIfNeeded() {
- if (!self::$registered) {
- stream_wrapper_register(
- self::PROTOCOL,
- self::class
- );
- self::$registered = true;
- }
- }
-
- /**
- * Open a readonly-seekable http stream
- *
- * The provided callback will be called with byte range and should return an http stream for the requested range
- *
- * @param callable $callback
- * @return false|resource
- */
- public static function open(callable $callback) {
- $context = stream_context_create([
- SeekableHttpStream::PROTOCOL => [
- 'callback' => $callback
- ],
- ]);
-
- SeekableHttpStream::registerIfNeeded();
- return fopen(SeekableHttpStream::PROTOCOL . '://', 'r', false, $context);
- }
-
- /** @var resource */
- public $context;
-
- /** @var callable */
- private $openCallback;
-
- /** @var resource */
- private $current;
- /** @var int */
- private $offset = 0;
-
- private function reconnect(int $start) {
- $range = $start . '-';
- if ($this->current != null) {
- fclose($this->current);
- }
-
- $this->current = ($this->openCallback)($range);
-
- if ($this->current === false) {
- return false;
- }
-
- $responseHead = stream_get_meta_data($this->current)['wrapper_data'];
- $rangeHeaders = array_values(array_filter($responseHead, function ($v) {
- return preg_match('#^content-range:#i', $v) === 1;
- }));
- if (!$rangeHeaders) {
- return false;
- }
- $contentRange = $rangeHeaders[0];
-
- $content = trim(explode(':', $contentRange)[1]);
- $range = trim(explode(' ', $content)[1]);
- $begin = intval(explode('-', $range)[0]);
-
- if ($begin !== $start) {
- return false;
- }
-
- $this->offset = $begin;
-
- return true;
- }
-
- public function stream_open($path, $mode, $options, &$opened_path) {
- $options = stream_context_get_options($this->context)[self::PROTOCOL];
- $this->openCallback = $options['callback'];
-
- return $this->reconnect(0);
- }
-
- public function stream_read($count) {
- if (!$this->current) {
- return false;
- }
- $ret = fread($this->current, $count);
- $this->offset += strlen($ret);
- return $ret;
- }
-
- public function stream_seek($offset, $whence = SEEK_SET) {
- switch ($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;
- }
-
- public function stream_tell() {
- return $this->offset;
- }
-
- public function stream_stat() {
- if (is_resource($this->current)) {
- return fstat($this->current);
- } else {
- return false;
- }
- }
-
- public function stream_eof() {
- if (is_resource($this->current)) {
- return feof($this->current);
- } else {
- return true;
- }
- }
-
- public function stream_close() {
- if (is_resource($this->current)) {
- fclose($this->current);
- }
- }
-
- public function stream_write($data) {
- return false;
- }
-
- public function stream_set_option($option, $arg1, $arg2) {
- return false;
- }
-
- public function stream_truncate($size) {
- return false;
- }
-
- public function stream_lock($operation) {
- return false;
- }
-
- public function stream_flush() {
- return; //noop because readonly stream
- }
- }
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