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| 1 | +<?php |
| 2 | +/** |
| 3 | + * |
| 4 | + * @copyright Copyright (c) 2020, Lukas Stabe (lukas@stabe.de) |
| 5 | + * |
| 6 | + * @license GNU AGPL version 3 or any later version |
| 7 | + * |
| 8 | + * This program is free software: you can redistribute it and/or modify |
| 9 | + * it under the terms of the GNU Affero General Public License as |
| 10 | + * published by the Free Software Foundation, either version 3 of the |
| 11 | + * License, or (at your option) any later version. |
| 12 | + * |
| 13 | + * This program is distributed in the hope that it will be useful, |
| 14 | + * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | + * GNU Affero General Public License for more details. |
| 17 | + * |
| 18 | + * You should have received a copy of the GNU Affero General Public License |
| 19 | + * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 20 | + * |
| 21 | + */ |
| 22 | + |
| 23 | +namespace OC\Files\Stream; |
| 24 | + |
| 25 | +use Icewind\Streams\File; |
| 26 | + |
| 27 | +/** |
| 28 | + * A stream wrapper that uses http range requests to provide a seekable stream for http reading |
| 29 | + */ |
| 30 | +class SeekableHttpStream implements File { |
| 31 | + private const PROTOCOL = 'httpseek'; |
| 32 | + |
| 33 | + private static $registered = false; |
| 34 | + |
| 35 | + /** |
| 36 | + * Registers the stream wrapper using the `httpseek://` url scheme |
| 37 | + * $return void |
| 38 | + */ |
| 39 | + private static function registerIfNeeded() { |
| 40 | + if (!self::$registered) { |
| 41 | + stream_wrapper_register( |
| 42 | + self::PROTOCOL, |
| 43 | + self::class |
| 44 | + ); |
| 45 | + self::$registered = true; |
| 46 | + } |
| 47 | + } |
| 48 | + |
| 49 | + /** |
| 50 | + * Open a readonly-seekable http stream |
| 51 | + * |
| 52 | + * The provided callback will be called with byte range and should return an http stream for the requested range |
| 53 | + * |
| 54 | + * @param callable $callback |
| 55 | + * @return false|resource |
| 56 | + */ |
| 57 | + public static function open(callable $callback) { |
| 58 | + $context = stream_context_create([ |
| 59 | + SeekableHttpStream::PROTOCOL => [ |
| 60 | + 'callback' => $callback |
| 61 | + ], |
| 62 | + ]); |
| 63 | + |
| 64 | + SeekableHttpStream::registerIfNeeded(); |
| 65 | + return fopen(SeekableHttpStream::PROTOCOL . '://', 'r', false, $context); |
| 66 | + } |
| 67 | + |
| 68 | + /** @var resource */ |
| 69 | + public $context; |
| 70 | + |
| 71 | + /** @var callable */ |
| 72 | + private $openCallback; |
| 73 | + |
| 74 | + /** @var resource */ |
| 75 | + private $current; |
| 76 | + /** @var int */ |
| 77 | + private $offset = 0; |
| 78 | + |
| 79 | + private function reconnect(int $start) { |
| 80 | + $range = $start . '-'; |
| 81 | + if ($this->current != null) { |
| 82 | + fclose($this->current); |
| 83 | + } |
| 84 | + |
| 85 | + $this->current = ($this->openCallback)($range); |
| 86 | + |
| 87 | + if ($this->current === false) { |
| 88 | + return false; |
| 89 | + } |
| 90 | + |
| 91 | + $responseHead = stream_get_meta_data($this->current)['wrapper_data']; |
| 92 | + $rangeHeaders = array_values(array_filter($responseHead, function ($v) { |
| 93 | + return preg_match('#^content-range:#i', $v) === 1; |
| 94 | + })); |
| 95 | + if (!$rangeHeaders) { |
| 96 | + return false; |
| 97 | + } |
| 98 | + $contentRange = $rangeHeaders[0]; |
| 99 | + |
| 100 | + $content = trim(explode(':', $contentRange)[1]); |
| 101 | + $range = trim(explode(' ', $content)[1]); |
| 102 | + $begin = intval(explode('-', $range)[0]); |
| 103 | + |
| 104 | + if ($begin !== $start) { |
| 105 | + return false; |
| 106 | + } |
| 107 | + |
| 108 | + $this->offset = $begin; |
| 109 | + |
| 110 | + return true; |
| 111 | + } |
| 112 | + |
| 113 | + public function stream_open($path, $mode, $options, &$opened_path) { |
| 114 | + $options = stream_context_get_options($this->context)[self::PROTOCOL]; |
| 115 | + $this->openCallback = $options['callback']; |
| 116 | + |
| 117 | + return $this->reconnect(0); |
| 118 | + } |
| 119 | + |
| 120 | + public function stream_read($count) { |
| 121 | + if (!$this->current) { |
| 122 | + return false; |
| 123 | + } |
| 124 | + $ret = fread($this->current, $count); |
| 125 | + $this->offset += strlen($ret); |
| 126 | + return $ret; |
| 127 | + } |
| 128 | + |
| 129 | + public function stream_seek($offset, $whence = SEEK_SET) { |
| 130 | + switch ($whence) { |
| 131 | + case SEEK_SET: |
| 132 | + if ($offset === $this->offset) { |
| 133 | + return true; |
| 134 | + } |
| 135 | + return $this->reconnect($offset); |
| 136 | + case SEEK_CUR: |
| 137 | + if ($offset === 0) { |
| 138 | + return true; |
| 139 | + } |
| 140 | + return $this->reconnect($this->offset + $offset); |
| 141 | + case SEEK_END: |
| 142 | + return false; |
| 143 | + } |
| 144 | + return false; |
| 145 | + } |
| 146 | + |
| 147 | + public function stream_tell() { |
| 148 | + return $this->offset; |
| 149 | + } |
| 150 | + |
| 151 | + public function stream_stat() { |
| 152 | + return fstat($this->current); |
| 153 | + } |
| 154 | + |
| 155 | + public function stream_eof() { |
| 156 | + return feof($this->current); |
| 157 | + } |
| 158 | + |
| 159 | + public function stream_close() { |
| 160 | + fclose($this->current); |
| 161 | + } |
| 162 | + |
| 163 | + public function stream_write($data) { |
| 164 | + return false; |
| 165 | + } |
| 166 | + |
| 167 | + public function stream_set_option($option, $arg1, $arg2) { |
| 168 | + return false; |
| 169 | + } |
| 170 | + |
| 171 | + public function stream_truncate($size) { |
| 172 | + return false; |
| 173 | + } |
| 174 | + |
| 175 | + public function stream_lock($operation) { |
| 176 | + return false; |
| 177 | + } |
| 178 | + |
| 179 | + public function stream_flush() { |
| 180 | + return; //noop because readonly stream |
| 181 | + } |
| 182 | +} |
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