filter/mediaplugin/filter.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  *  Media plugin filtering
  19  *
  20  *  This filter will replace any links to a media file with
  21  *  a media plugin that plays that media inline
  22  *
  23  * @package    filter
  24  * @subpackage mediaplugin
  25  * @copyright  2004 onwards Martin Dougiamas  {@link http://moodle.com}
  26  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  27  */
  28
  29 defined('MOODLE_INTERNAL') || die();
  30
  31 /**
  32  * Automatic media embedding filter class.
  33  *
  34  * It is highly recommended to configure servers to be compatible with our slasharguments,
  35  * otherwise the "?d=600x400" may not work.
  36  *
  37  * @package    filter
  38  * @subpackage mediaplugin
  39  * @copyright  2004 onwards Martin Dougiamas  {@link http://moodle.com}
  40  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  41  */
  42 class filter_mediaplugin extends moodle_text_filter {
  43     /** @var bool True if currently filtering trusted text */
  44     private $trusted;
  45     /** @var core_media_renderer Media renderer */
  46     private $mediarenderer;
  47     /** @var string Partial regex pattern indicating possible embeddable content */
  48     private $embedmarkers;
  49
  50     public function filter($text, array $options = array()) {
  51         global $CFG, $PAGE;
  52
  53         if (!is_string($text) or empty($text)) {
  54             // non string data can not be filtered anyway
  55             return $text;
  56         }
  57
  58         if (stripos($text, '</a>') === false) {
  59             // Performance shortcut - if not </a> tag, nothing can match.
  60             return $text;
  61         }
  62
  63         if (!$this->mediarenderer) {
  64             $this->mediarenderer = $PAGE->get_renderer('core', 'media');
  65             $this->embedmarkers = $this->mediarenderer->get_embeddable_markers();
  66         }
  67
  68         // Check SWF permissions.
  69         $this->trusted = !empty($options['noclean']) or !empty($CFG->allowobjectembed);
  70
  71         // Handle all links that contain any 'embeddable' marker text (it could
  72         // do all links, but the embeddable markers thing should make it faster
  73         // by meaning for most links it doesn't drop into PHP code).
  74         $newtext = preg_replace_callback($re = '~<a\s[^>]*href="([^"]*(?:' .
  75                 $this->embedmarkers . ')[^"]*)"[^>]*>([^>]*)</a>~is',
  76                 array($this, 'callback'), $text);
  77
  78         if (empty($newtext) or $newtext === $text) {
  79             // error or not filtered
  80             return $text;
  81         }
  82
  83         return $newtext;
  84     }
  85
  86     /**
  87      * Replace link with embedded content, if supported.
  88      *
  89      * @param array $matches
  90      * @return string
  91      */
  92     private function callback(array $matches) {
  93         global $CFG, $PAGE;
  94         // Check if we ignore it.
  95         if (preg_match('/class="[^"]*nomediaplugin/i', $matches[0])) {
  96             return $matches[0];
  97         }
  98
  99         // Get name.
 100         $name = trim($matches[2]);
 101         if (empty($name) or strpos($name, 'http') === 0) {
 102             $name = ''; // Use default name.
 103         }
 104
 105         // Split provided URL into alternatives.
 106         $urls = core_media::split_alternatives($matches[1], $width, $height);
 107
 108         $options = array();
 109
 110         // Allow SWF (or not).
 111         if ($this->trusted) {
 112             $options[core_media::OPTION_TRUSTED] = true;
 113         }
 114
 115         // We could test whether embed is possible using can_embed, but to save
 116         // time, let's just embed it with the 'fallback to blank' option which
 117         // does most of the same stuff anyhow.
 118         $options[core_media::OPTION_FALLBACK_TO_BLANK] = true;
 119
 120         // NOTE: Options are not passed through from filter because the 'embed'
 121         // code does not recognise filter options (it's a different kind of
 122         // option-space) as it can be used in non-filter situations.
 123         $result = $this->mediarenderer->embed_alternatives($urls, $name, $width, $height, $options);
 124
 125         // If something was embedded, return it, otherwise return original.
 126         if ($result !== '') {
 127             return $result;
 128         } else {
 129             return $matches[0];
 130         }
 131     }
 132 }