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See Release Notes

  • Bug fixes for general core bugs in 3.10.x will end 8 November 2021 (12 months).
  • Bug fixes for security issues in 3.10.x will end 9 May 2022 (18 months).
  • PHP version: minimum PHP 7.2.0 Note: minimum PHP version has increased since Moodle 3.8. PHP 7.3.x and 7.4.x are supported too.
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 *  Media plugin filtering
 *
 *  This filter will replace any links to a media file with
 *  a media plugin that plays that media inline
 *
 * @package    filter
 * @subpackage mediaplugin
 * @copyright  2004 onwards Martin Dougiamas  {@link http://moodle.com}
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die();

/**
 * Automatic media embedding filter class.
 *
 * It is highly recommended to configure servers to be compatible with our slasharguments,
 * otherwise the "?d=600x400" may not work.
 *
 * @package    filter
 * @subpackage mediaplugin
 * @copyright  2004 onwards Martin Dougiamas  {@link http://moodle.com}
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class filter_mediaplugin extends moodle_text_filter {
    /** @var bool True if currently filtering trusted text */
    private $trusted;

    /**
     * Setup page with filter requirements and other prepare stuff.
     *
     * @param moodle_page $page The page we are going to add requirements to.
     * @param context $context The context which contents are going to be filtered.
     */
    public function setup($page, $context) {
        // This only requires execution once per request.
        static $jsinitialised = false;
        if ($jsinitialised) {
            return;
        }
        $jsinitialised = true;

        // Set up the media manager so that media plugins requiring JS are initialised.
        $mediamanager = core_media_manager::instance($page);
    }

    public function filter($text, array $options = array()) {
        global $CFG, $PAGE;

        if (!is_string($text) or empty($text)) {
            // non string data can not be filtered anyway
            return $text;
        }

        if (stripos($text, '</a>') === false && stripos($text, '</video>') === false && stripos($text, '</audio>') === false) {
            // Performance shortcut - if there are no </a>, </video> or </audio> tags, nothing can match.
            return $text;
        }

< // Check SWF permissions.
> // Check permissions.
$this->trusted = !empty($options['noclean']) or !empty($CFG->allowobjectembed); // Looking for tags. $matches = preg_split('/(<[^>]*>)/i', $text, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE); if (!$matches) { return $text; } // Regex to find media extensions in an <a> tag. $embedmarkers = core_media_manager::instance()->get_embeddable_markers(); $re = '~<a\s[^>]*href="([^"]*(?:' . $embedmarkers . ')[^"]*)"[^>]*>([^>]*)</a>~is'; $newtext = ''; $validtag = ''; $tagname = ''; $sizeofmatches = count($matches); // We iterate through the given string to find valid <a> tags // and build them so that the callback function can check it for // embedded content. Then we rebuild the string. foreach ($matches as $idx => $tag) { if (preg_match('|</'.$tagname.'>|', $tag) && !empty($validtag)) { $validtag .= $tag; // Given we now have a valid <a> tag to process it's time for // ReDoS protection. Stop processing if a word is too large. if (strlen($validtag) < 4096) { if ($tagname === 'a') { $processed = preg_replace_callback($re, array($this, 'callback'), $validtag); } else { // For audio and video tags we just process them without precheck for embeddable markers. $processed = $this->process_media_tag($validtag); } } // Rebuilding the string with our new processed text. $newtext .= !empty($processed) ? $processed : $validtag; // Wipe it so we can catch any more instances to filter. $validtag = ''; $processed = ''; } else if (preg_match('/<(a|video|audio)\s[^>]*/', $tag, $tagmatches) && $sizeofmatches > 1 && (empty($validtag) || $tagname === strtolower($tagmatches[1]))) { // Looking for a starting tag. Ignore tags embedded into each other. $validtag = $tag; $tagname = strtolower($tagmatches[1]); } else { // If we have a validtag add to that to process later, // else add straight onto our newtext string. if (!empty($validtag)) { $validtag .= $tag; } else { $newtext .= $tag; } } } // Return the same string except processed by the above. return $newtext; } /** * Replace link with embedded content, if supported. * * @param array $matches * @return string */ private function callback(array $matches) { $mediamanager = core_media_manager::instance(); global $CFG, $PAGE; // Check if we ignore it. if (preg_match('/class="[^"]*nomediaplugin/i', $matches[0])) { return $matches[0]; } // Get name. $name = trim($matches[2]); if (empty($name) or strpos($name, 'http') === 0) { $name = ''; // Use default name. } // Split provided URL into alternatives. $urls = $mediamanager->split_alternatives($matches[1], $width, $height); $options = [core_media_manager::OPTION_ORIGINAL_TEXT => $matches[0]]; return $this->embed_alternatives($urls, $name, $width, $height, $options); } /** * Renders media files (audio or video) using suitable embedded player. * * Wrapper for {@link core_media_manager::embed_alternatives()} * * @param array $urls Array of moodle_url to media files * @param string $name Optional user-readable name to display in download link * @param int $width Width in pixels (optional) * @param int $height Height in pixels (optional) * @param array $options Array of key/value pairs * @return string HTML content of embed */ protected function embed_alternatives($urls, $name, $width, $height, $options) {
< // Allow SWF (or not).
> // Allow trusted content (or not).
if ($this->trusted) { $options[core_media_manager::OPTION_TRUSTED] = true; } // We could test whether embed is possible using can_embed, but to save // time, let's just embed it with the 'fallback to blank' option which // does most of the same stuff anyhow. $options[core_media_manager::OPTION_FALLBACK_TO_BLANK] = true; // NOTE: Options are not passed through from filter because the 'embed' // code does not recognise filter options (it's a different kind of // option-space) as it can be used in non-filter situations. $result = core_media_manager::instance()->embed_alternatives($urls, $name, $width, $height, $options); // If something was embedded, return it, otherwise return original. if ($result !== '') { return $result; } else { return $options[core_media_manager::OPTION_ORIGINAL_TEXT]; } } /** * Replaces <video> or <audio> tag with processed contents * * @param string $fulltext complete HTML snipped "<video ...>...</video>" or "<audio ...>....</audio>" * @return string */ protected function process_media_tag($fulltext) { // Check if we ignore it. if (preg_match('/^<[^>]*class="[^"]*nomediaplugin/im', $fulltext)) { return $fulltext; } // Find all sources both as <video src=""> and as embedded <source> tags. $urls = []; if (preg_match('/^<[^>]*\bsrc="(.*?)"/im', $fulltext, $matches)) { $urls[] = new moodle_url($matches[1]); } if (preg_match_all('/<source\b[^>]*\bsrc="(.*?)"/im', $fulltext, $matches)) { foreach ($matches[1] as $url) { $urls[] = new moodle_url($url); } } // Extract width/height/title attributes and call embed_alternatives to find a suitable media player. if ($urls) { $options = [core_media_manager::OPTION_ORIGINAL_TEXT => $fulltext]; $width = core_media_player_native::get_attribute($fulltext, 'width', PARAM_INT); $height = core_media_player_native::get_attribute($fulltext, 'height', PARAM_INT); $name = core_media_player_native::get_attribute($fulltext, 'title'); return $this->embed_alternatives($urls, $name, $width, $height, $options); } return $fulltext; } }