lib/wasmlib.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * This file contains various Web Assembly related functions,
  19  * all functions here are self-contained and can be used in ABORT_AFTER_CONFIG scripts.
  20  *
  21  * @package core_lib
  22  * @copyright 2021 Huong Nguyen <huongnv13@gmail.com>
  23  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24  */
  25
  26 defined('MOODLE_INTERNAL') || die();
  27
  28 /**
  29  * Send Web Assembly file content with as much caching as possible
  30  *
  31  * @param string $wasmpath Path to Web Assembly file
  32  * @param string $etag Etag
  33  * @param string $filename File name to be served
  34  */
  35 function wasm_send_cached(string $wasmpath, string $etag, string $filename = 'wasm.php'): void {
  36     require(__DIR__ . '/xsendfilelib.php');
  37
  38     // 90 days only - based on Moodle point release cadence being every 3 months.
  39     $lifetime = 60 * 60 * 24 * 90;
  40
  41     header('Etag: "' . $etag . '"');
  42     header('Content-Disposition: inline; filename="' . $filename . '"');
  43     header('Last-Modified: ' . gmdate('D, d M Y H:i:s', filemtime($wasmpath)) . ' GMT');
  44     header('Expires: ' . gmdate('D, d M Y H:i:s', time() + $lifetime) . ' GMT');
  45     header('Pragma: ');
  46     header('Cache-Control: public, max-age=' . $lifetime . ', immutable');
  47     header('Accept-Ranges: none');
  48     header('Content-Type: application/wasm');
  49
  50     if (xsendfile($wasmpath)) {
  51         die;
  52     }
  53
  54     if (!min_enable_zlib_compression()) {
  55         header('Content-Length: ' . filesize($wasmpath));
  56     }
  57
  58     readfile($wasmpath);
  59     die;
  60 }
  61
  62 /**
  63  * Send Web Assembly file without any caching
  64  *
  65  * @param string $wasm Web Assembly file content
  66  * @param string $filename File name to be served
  67  */
  68 function wasm_send_uncached(string $wasm, string $filename = 'wasm.php'): void {
  69     header('Content-Disposition: inline; filename="' . $filename . '"');
  70     header('Last-Modified: ' . gmdate('D, d M Y H:i:s', time()) . ' GMT');
  71     header('Expires: ' . gmdate('D, d M Y H:i:s', time() + 2) . ' GMT');
  72     header('Pragma: ');
  73     header('Accept-Ranges: none');
  74     header('Content-Type: application/wasm');
  75     header('Content-Length: ' . strlen($wasm));
  76
  77     echo $wasm;
  78     die;
  79 }
  80
  81 /**
  82  * Send Web Assembly file not modified headers
  83  *
  84  * @param int $lastmodified Last modified timestamp
  85  * @param string $etag Etag
  86  */
  87 function wasm_send_unmodified(int $lastmodified, string $etag): void {
  88     // 90 days only - based on Moodle point release cadence being every 3 months.
  89     $lifetime = 60 * 60 * 24 * 90;
  90     header('HTTP/1.1 304 Not Modified');
  91     header('Expires: ' . gmdate('D, d M Y H:i:s', time() + $lifetime) . ' GMT');
  92     header('Cache-Control: public, max-age=' . $lifetime);
  93     header('Content-Type: application/wasm');
  94     header('Etag: "' . $etag . '"');
  95     if ($lastmodified) {
  96         header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $lastmodified) . ' GMT');
  97     }
  98     die;
  99 }
 100
 101 /**
 102  * Create cache file for Web Assembly content
 103  *
 104  * @param string $file full file path to cache file
 105  * @param string $content Web Assembly content
 106  */
 107 function wasm_write_cache_file_content(string $file, string $content): void {
 108     global $CFG;
 109
 110     clearstatcache();
 111     if (!file_exists(dirname($file))) {
 112         @mkdir(dirname($file), $CFG->directorypermissions, true);
 113     }
 114
 115     // Prevent serving of incomplete file from concurrent request,
 116     // the rename() should be more atomic than fwrite().
 117     ignore_user_abort(true);
 118     if ($fp = fopen($file . '.tmp', 'xb')) {
 119         fwrite($fp, $content);
 120         fclose($fp);
 121         rename($file . '.tmp', $file);
 122         @chmod($file, $CFG->filepermissions);
 123         @unlink($file . '.tmp'); // Just in case anything fails.
 124     }
 125     ignore_user_abort(false);
 126     if (connection_aborted()) {
 127         die;
 128     }
 129 }