/filter/mediaplugin/filter.php
PHP | 235 lines | 107 code | 28 blank | 100 comment | 28 complexity | cca998b57476be46d3a2f45dc1700e48 MD5 | raw file
Possible License(s): BSD-3-Clause, MIT, GPL-3.0, Apache-2.0, LGPL-2.1
- <?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 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, $options) {
- // Allow trusted content (or not).
- if ($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;
- }
- }