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194 lines
4.4 KiB
194 lines
4.4 KiB
<?php
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/**
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* @copyright Copyright (c) 2020, Lukas Stabe (lukas@stabe.de)
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*
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* @author Lukas Stabe <lukas@stabe.de>
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* @author Robin Appelman <robin@icewind.nl>
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*
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* @license GNU AGPL version 3 or any later version
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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namespace OC\Files\Stream;
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use Icewind\Streams\File;
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/**
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* A stream wrapper that uses http range requests to provide a seekable stream for http reading
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*/
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class SeekableHttpStream implements File {
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private const PROTOCOL = 'httpseek';
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private static $registered = false;
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/**
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* Registers the stream wrapper using the `httpseek://` url scheme
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* $return void
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*/
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private static function registerIfNeeded() {
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if (!self::$registered) {
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stream_wrapper_register(
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self::PROTOCOL,
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self::class
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);
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self::$registered = true;
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}
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}
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/**
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* Open a readonly-seekable http stream
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*
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* The provided callback will be called with byte range and should return an http stream for the requested range
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*
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* @param callable $callback
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* @return false|resource
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*/
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public static function open(callable $callback) {
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$context = stream_context_create([
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SeekableHttpStream::PROTOCOL => [
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'callback' => $callback
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],
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]);
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SeekableHttpStream::registerIfNeeded();
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return fopen(SeekableHttpStream::PROTOCOL . '://', 'r', false, $context);
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}
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/** @var resource */
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public $context;
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/** @var callable */
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private $openCallback;
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/** @var resource */
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private $current;
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/** @var int */
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private $offset = 0;
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private function reconnect(int $start) {
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$range = $start . '-';
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if ($this->current != null) {
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fclose($this->current);
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}
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$this->current = ($this->openCallback)($range);
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if ($this->current === false) {
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return false;
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}
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$responseHead = stream_get_meta_data($this->current)['wrapper_data'];
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$rangeHeaders = array_values(array_filter($responseHead, function ($v) {
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return preg_match('#^content-range:#i', $v) === 1;
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}));
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if (!$rangeHeaders) {
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return false;
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}
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$contentRange = $rangeHeaders[0];
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$content = trim(explode(':', $contentRange)[1]);
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$range = trim(explode(' ', $content)[1]);
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$begin = intval(explode('-', $range)[0]);
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if ($begin !== $start) {
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return false;
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}
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$this->offset = $begin;
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return true;
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}
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public function stream_open($path, $mode, $options, &$opened_path) {
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$options = stream_context_get_options($this->context)[self::PROTOCOL];
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$this->openCallback = $options['callback'];
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return $this->reconnect(0);
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}
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public function stream_read($count) {
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if (!$this->current) {
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return false;
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}
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$ret = fread($this->current, $count);
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$this->offset += strlen($ret);
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return $ret;
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}
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public function stream_seek($offset, $whence = SEEK_SET) {
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switch ($whence) {
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case SEEK_SET:
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if ($offset === $this->offset) {
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return true;
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}
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return $this->reconnect($offset);
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case SEEK_CUR:
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if ($offset === 0) {
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return true;
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}
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return $this->reconnect($this->offset + $offset);
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case SEEK_END:
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return false;
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}
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return false;
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}
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public function stream_tell() {
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return $this->offset;
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}
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public function stream_stat() {
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if (is_resource($this->current)) {
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return fstat($this->current);
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} else {
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return false;
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}
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}
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public function stream_eof() {
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if (is_resource($this->current)) {
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return feof($this->current);
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} else {
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return true;
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}
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}
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public function stream_close() {
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if (is_resource($this->current)) {
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fclose($this->current);
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}
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}
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public function stream_write($data) {
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return false;
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}
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public function stream_set_option($option, $arg1, $arg2) {
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return false;
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}
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public function stream_truncate($size) {
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return false;
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}
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public function stream_lock($operation) {
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return false;
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}
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public function stream_flush() {
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return; //noop because readonly stream
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}
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}
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