lib/medialib.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  * Classes for handling embedded media (mainly audio and video).
  19  *
  20  * These are used only from within the core media renderer.
  21  *
  22  * To embed media from Moodle code, do something like the following:
  23  *
  24  * $mediarenderer = $PAGE->get_renderer('core', 'media');
  25  * echo $mediarenderer->embed_url(new moodle_url('http://example.org/a.mp3'));
  26  *
  27  * You do not need to require this library file manually. Getting the renderer
  28  * (the first line above) requires this library file automatically.
  29  *
  30  * @package core_media
  31  * @copyright 2012 The Open University
  32  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  33  */
  34
  35 defined('MOODLE_INTERNAL') || die();
  36
  37 if (!defined('CORE_MEDIA_VIDEO_WIDTH')) {
  38     // Default video width if no width is specified; some players may do something
  39     // more intelligent such as use real video width.
  40     // May be defined in config.php if required.
  41     define('CORE_MEDIA_VIDEO_WIDTH', 400);
  42 }
  43 if (!defined('CORE_MEDIA_VIDEO_HEIGHT')) {
  44     // Default video height. May be defined in config.php if required.
  45     define('CORE_MEDIA_VIDEO_HEIGHT', 300);
  46 }
  47 if (!defined('CORE_MEDIA_AUDIO_WIDTH')) {
  48     // Default audio width if no width is specified.
  49     // May be defined in config.php if required.
  50     define('CORE_MEDIA_AUDIO_WIDTH', 300);
  51 }
  52
  53
  54 /**
  55  * Constants and static utility functions for use with core_media_renderer.
  56  *
  57  * @copyright 2011 The Open University
  58  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  59  */
  60 abstract class core_media {
  61     /**
  62      * Option: Disable text link fallback.
  63      *
  64      * Use this option if you are going to print a visible link anyway so it is
  65      * pointless to have one as fallback.
  66      *
  67      * To enable, set value to true.
  68      */
  69     const OPTION_NO_LINK = 'nolink';
  70
  71     /**
  72      * Option: When embedding, if there is no matching embed, do not use the
  73      * default link fallback player; instead return blank.
  74      *
  75      * This is different from OPTION_NO_LINK because this option still uses the
  76      * fallback link if there is some kind of embedding. Use this option if you
  77      * are going to check if the return value is blank and handle it specially.
  78      *
  79      * To enable, set value to true.
  80      */
  81     const OPTION_FALLBACK_TO_BLANK = 'embedorblank';
  82
  83     /**
  84      * Option: Enable players which are only suitable for use when we trust the
  85      * user who embedded the content.
  86      *
  87      * At present, this option enables the SWF player.
  88      *
  89      * To enable, set value to true.
  90      */
  91     const OPTION_TRUSTED = 'trusted';
  92
  93     /**
  94      * Option: Put a div around the output (if not blank) so that it displays
  95      * as a block using the 'resourcecontent' CSS class.
  96      *
  97      * To enable, set value to true.
  98      */
  99     const OPTION_BLOCK = 'block';
 100
 101     /**
 102      * Given a string containing multiple URLs separated by #, this will split
 103      * it into an array of moodle_url objects suitable for using when calling
 104      * embed_alternatives.
 105      *
 106      * Note that the input string should NOT be html-escaped (i.e. if it comes
 107      * from html, call html_entity_decode first).
 108      *
 109      * @param string $combinedurl String of 1 or more alternatives separated by #
 110      * @param int $width Output variable: width (will be set to 0 if not specified)
 111      * @param int $height Output variable: height (0 if not specified)
 112      * @return array Array of 1 or more moodle_url objects
 113      */
 114     public static function split_alternatives($combinedurl, &$width, &$height) {
 115         $urls = explode('#', $combinedurl);
 116         $width = 0;
 117         $height = 0;
 118         $returnurls = array();
 119
 120         foreach ($urls as $url) {
 121             $matches = null;
 122
 123             // You can specify the size as a separate part of the array like
 124             // #d=640x480 without actually including a url in it.
 125             if (preg_match('/^d=([\d]{1,4})x([\d]{1,4})$/i', $url, $matches)) {
 126                 $width  = $matches[1];
 127                 $height = $matches[2];
 128                 continue;
 129             }
 130
 131             // Can also include the ?d= as part of one of the URLs (if you use
 132             // more than one they will be ignored except the last).
 133             if (preg_match('/\?d=([\d]{1,4})x([\d]{1,4})$/i', $url, $matches)) {
 134                 $width  = $matches[1];
 135                 $height = $matches[2];
 136
 137                 // Trim from URL.
 138                 $url = str_replace($matches[0], '', $url);
 139             }
 140
 141             // Clean up url.
 142             $url = clean_param($url, PARAM_URL);
 143             if (empty($url)) {
 144                 continue;
 145             }
 146
 147             // Turn it into moodle_url object.
 148             $returnurls[] = new moodle_url($url);
 149         }
 150
 151         return $returnurls;
 152     }
 153
 154     /**
 155      * Returns the file extension for a URL.
 156      * @param moodle_url $url URL
 157      */
 158     public static function get_extension(moodle_url $url) {
 159         // Note: Does not use core_text (. is UTF8-safe).
 160         $filename = self::get_filename($url);
 161         $dot = strrpos($filename, '.');
 162         if ($dot === false) {
 163             return '';
 164         } else {
 165             return strtolower(substr($filename, $dot + 1));
 166         }
 167     }
 168
 169     /**
 170      * Obtains the filename from the moodle_url.
 171      * @param moodle_url $url URL
 172      * @return string Filename only (not escaped)
 173      */
 174     public static function get_filename(moodle_url $url) {
 175         global $CFG;
 176
 177         // Use the 'file' parameter if provided (for links created when
 178         // slasharguments was off). If not present, just use URL path.
 179         $path = $url->get_param('file');
 180         if (!$path) {
 181             $path = $url->get_path();
 182         }
 183
 184         // Remove everything before last / if present. Does not use textlib as / is UTF8-safe.
 185         $slash = strrpos($path, '/');
 186         if ($slash !== false) {
 187             $path = substr($path, $slash + 1);
 188         }
 189         return $path;
 190     }
 191
 192     /**
 193      * Guesses MIME type for a moodle_url based on file extension.
 194      * @param moodle_url $url URL
 195      * @return string MIME type
 196      */
 197     public static function get_mimetype(moodle_url $url) {
 198         return mimeinfo('type', self::get_filename($url));
 199     }
 200 }
 201
 202
 203 /**
 204  * Base class for media players.
 205  *
 206  * Media players return embed HTML for a particular way of playing back audio
 207  * or video (or another file type).
 208  *
 209  * In order to make the code more lightweight, this is not a plugin type
 210  * (players cannot have their own settings, database tables, capabilities, etc).
 211  * These classes are used only by core_media_renderer in outputrenderers.php.
 212  * If you add a new class here (in core code) you must modify the
 213  * get_players_raw function in that file to include it.
 214  *
 215  * If a Moodle installation wishes to add extra player objects they can do so
 216  * by overriding that renderer in theme, and overriding the get_players_raw
 217  * function. The new player class should then of course be defined within the
 218  * custom theme or other suitable location, not in this file.
 219  *
 220  * @copyright 2011 The Open University
 221  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 222  */
 223 abstract class core_media_player {
 224     /**
 225      * Placeholder text used to indicate where the fallback content is placed
 226      * within a result.
 227      */
 228     const PLACEHOLDER = '<!--FALLBACK-->';
 229
 230     /**
 231      * Generates code required to embed the player.
 232      *
 233      * The returned code contains a placeholder comment '<!--FALLBACK-->'
 234      * (constant core_media_player::PLACEHOLDER) which indicates the location
 235      * where fallback content should be placed in the event that this type of
 236      * player is not supported by user browser.
 237      *
 238      * The $urls parameter includes one or more alternative media formats that
 239      * are supported by this player. It does not include formats that aren't
 240      * supported (see list_supported_urls).
 241      *
 242      * The $options array contains key-value pairs. See OPTION_xx constants
 243      * for documentation of standard option(s).
 244      *
 245      * @param array $urls URLs of media files
 246      * @param string $name Display name; '' to use default
 247      * @param int $width Optional width; 0 to use default
 248      * @param int $height Optional height; 0 to use default
 249      * @param array $options Options array
 250      * @return string HTML code for embed
 251      */
 252     public abstract function embed($urls, $name, $width, $height, $options);
 253
 254     /**
 255      * Gets the list of file extensions supported by this media player.
 256      *
 257      * Note: This is only required for the default implementation of
 258      * list_supported_urls. If you override that function to determine
 259      * supported URLs in some way other than by extension, then this function
 260      * is not necessary.
 261      *
 262      * @return array Array of strings (extension not including dot e.g. 'mp3')
 263      */
 264     public function get_supported_extensions() {
 265         return array();
 266     }
 267
 268     /**
 269      * Lists keywords that must be included in a url that can be embedded with
 270      * this player. Any such keywords should be added to the array.
 271      *
 272      * For example if this player supports FLV and F4V files then it should add
 273      * '.flv' and '.f4v' to the array. (The check is not case-sensitive.)
 274      *
 275      * Default handling calls the get_supported_extensions function and adds
 276      * a dot to each of those values, so players only need to override this
 277      * if they don't implement get_supported_extensions.
 278      *
 279      * This is used to improve performance when matching links in the media filter.
 280      *
 281      * @return array Array of keywords to add to the embeddable markers list
 282      */
 283     public function get_embeddable_markers() {
 284         $markers = array();
 285         foreach ($this->get_supported_extensions() as $extension) {
 286             $markers[] = '.' . $extension;
 287         }
 288         return $markers;
 289     }
 290
 291     /**
 292      * Gets the ranking of this player. This is an integer used to decide which
 293      * player to use (after applying other considerations such as which ones
 294      * the user has disabled).
 295      *
 296      * Rank must be unique (no two players should have the same rank).
 297      *
 298      * Rank zero has a special meaning, indicating that this 'player' does not
 299      * really embed the video.
 300      *
 301      * Rank is not a user-configurable value because it needs to be defined
 302      * carefully in order to ensure that the embedding fallbacks actually work.
 303      * It might be possible to have some user options which affect rank, but
 304      * these would be best defined as e.g. checkboxes in settings that have
 305      * a particular effect on the rank of a couple of plugins, rather than
 306      * letting users generally alter rank.
 307      *
 308      * Note: Within medialib.php, players are listed in rank order (highest
 309      * rank first).
 310      *
 311      * @return int Rank (higher is better)
 312      */
 313     public abstract function get_rank();
 314
 315     /**
 316      * @return bool True if player is enabled
 317      */
 318     public function is_enabled() {
 319         global $CFG;
 320
 321         // With the class core_media_player_html5video it is enabled
 322         // based on $CFG->core_media_enable_html5video.
 323         $setting = str_replace('_player_', '_enable_', get_class($this));
 324         return !empty($CFG->{$setting});
 325     }
 326
 327     /**
 328      * Given a list of URLs, returns a reduced array containing only those URLs
 329      * which are supported by this player. (Empty if none.)
 330      * @param array $urls Array of moodle_url
 331      * @param array $options Options (same as will be passed to embed)
 332      * @return array Array of supported moodle_url
 333      */
 334     public function list_supported_urls(array $urls, array $options = array()) {
 335         $extensions = $this->get_supported_extensions();
 336         $result = array();
 337         foreach ($urls as $url) {
 338             if (in_array(core_media::get_extension($url), $extensions)) {
 339                 $result[] = $url;
 340             }
 341         }
 342         return $result;
 343     }
 344
 345     /**
 346      * Obtains suitable name for media. Uses specified name if there is one,
 347      * otherwise makes one up.
 348      * @param string $name User-specified name ('' if none)
 349      * @param array $urls Array of moodle_url used to make up name
 350      * @return string Name
 351      */
 352     protected function get_name($name, $urls) {
 353         // If there is a specified name, use that.
 354         if ($name) {
 355             return $name;
 356         }
 357
 358         // Get filename of first URL.
 359         $url = reset($urls);
 360         $name = core_media::get_filename($url);
 361
 362         // If there is more than one url, strip the extension as we could be
 363         // referring to a different one or several at once.
 364         if (count($urls) > 1) {
 365             $name = preg_replace('~\.[^.]*$~', '', $name);
 366         }
 367
 368         return $name;
 369     }
 370
 371     /**
 372      * Compares by rank order, highest first. Used for sort functions.
 373      * @param core_media_player $a Player A
 374      * @param core_media_player $b Player B
 375      * @return int Negative if A should go before B, positive for vice versa
 376      */
 377     public static function compare_by_rank(core_media_player $a, core_media_player $b) {
 378         return $b->get_rank() - $a->get_rank();
 379     }
 380
 381     /**
 382      * Utility function that sets width and height to defaults if not specified
 383      * as a parameter to the function (will be specified either if, (a) the calling
 384      * code passed it, or (b) the URL included it).
 385      * @param int $width Width passed to function (updated with final value)
 386      * @param int $height Height passed to function (updated with final value)
 387      */
 388     protected static function pick_video_size(&$width, &$height) {
 389         if (!$width) {
 390             $width = CORE_MEDIA_VIDEO_WIDTH;
 391             $height = CORE_MEDIA_VIDEO_HEIGHT;
 392         }
 393     }
 394 }
 395
 396
 397 /**
 398  * Base class for players which handle external links (YouTube etc).
 399  *
 400  * As opposed to media files.
 401  *
 402  * @copyright 2011 The Open University
 403  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 404  */
 405 abstract class core_media_player_external extends core_media_player {
 406     /**
 407      * Array of matches from regular expression - subclass can assume these
 408      * will be valid when the embed function is called, to save it rerunning
 409      * the regex.
 410      * @var array
 411      */
 412     protected $matches;
 413
 414     /**
 415      * Part of a regular expression, including ending ~ symbol (note: these
 416      * regexes use ~ instead of / because URLs and HTML code typically include
 417      * / symbol and makes harder to read if you have to escape it).
 418      * Matches the end part of a link after you have read the 'important' data
 419      * including optional #d=400x300 at end of url, plus content of <a> tag,
 420      * up to </a>.
 421      * @var string
 422      */
 423     const END_LINK_REGEX_PART = '[^#]*(#d=([\d]{1,4})x([\d]{1,4}))?~si';
 424
 425     public function embed($urls, $name, $width, $height, $options) {
 426         return $this->embed_external(reset($urls), $name, $width, $height, $options);
 427     }
 428
 429     /**
 430      * Obtains HTML code to embed the link.
 431      * @param moodle_url $url Single URL to embed
 432      * @param string $name Display name; '' to use default
 433      * @param int $width Optional width; 0 to use default
 434      * @param int $height Optional height; 0 to use default
 435      * @param array $options Options array
 436      * @return string HTML code for embed
 437      */
 438     protected abstract function embed_external(moodle_url $url, $name, $width, $height, $options);
 439
 440     public function list_supported_urls(array $urls, array $options = array()) {
 441         // These only work with a SINGLE url (there is no fallback).
 442         if (count($urls) != 1) {
 443             return array();
 444         }
 445         $url = reset($urls);
 446
 447         // Check against regex.
 448         if (preg_match($this->get_regex(), $url->out(false), $this->matches)) {
 449             return array($url);
 450         }
 451
 452         return array();
 453     }
 454
 455     /**
 456      * Returns regular expression used to match URLs that this player handles
 457      * @return string PHP regular expression e.g. '~^https?://example.org/~'
 458      */
 459     protected function get_regex() {
 460         return '~^unsupported~';
 461     }
 462
 463     /**
 464      * Annoyingly, preg_match $matches result does not always have the same
 465      * number of parameters - it leaves out optional ones at the end. WHAT.
 466      * Anyway, this function can be used to fix it.
 467      * @param array $matches Array that should be adjusted
 468      * @param int $count Number of capturing groups (=6 to make $matches[6] work)
 469      */
 470     protected static function fix_match_count(&$matches, $count) {
 471         for ($i = count($matches); $i <= $count; $i++) {
 472             $matches[$i] = false;
 473         }
 474     }
 475 }
 476
 477
 478 /**
 479  * Player that embeds Vimeo links.
 480  *
 481  * @copyright 2011 The Open University
 482  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 483  */
 484 class core_media_player_vimeo extends core_media_player_external {
 485     protected function embed_external(moodle_url $url, $name, $width, $height, $options) {
 486         $videoid = $this->matches[1];
 487         $info = s($name);
 488
 489         // Note: resizing via url is not supported, user can click the fullscreen
 490         // button instead. iframe embedding is not xhtml strict but it is the only
 491         // option that seems to work on most devices.
 492         self::pick_video_size($width, $height);
 493
 494         $output = <<<OET
 495 <span class="mediaplugin mediaplugin_vimeo">
 496 <iframe title="$info" src="https://player.vimeo.com/video/$videoid"
 497   width="$width" height="$height" frameborder="0"
 498   webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>
 499 </span>
 500 OET;
 501
 502         return $output;
 503     }
 504
 505     protected function get_regex() {
 506         // Initial part of link.
 507         $start = '~^https?://vimeo\.com/';
 508         // Middle bit: either watch?v= or v/.
 509         $middle = '([0-9]+)';
 510         return $start . $middle . core_media_player_external::END_LINK_REGEX_PART;
 511     }
 512
 513     public function get_rank() {
 514         return 1010;
 515     }
 516
 517     public function get_embeddable_markers() {
 518         return array('vimeo.com/');
 519     }
 520 }
 521
 522 /**
 523  * Player that creates YouTube embedding.
 524  *
 525  * @copyright 2011 The Open University
 526  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 527  */
 528 class core_media_player_youtube extends core_media_player_external {
 529     protected function embed_external(moodle_url $url, $name, $width, $height, $options) {
 530         $videoid = end($this->matches);
 531
 532         $info = trim($name);
 533         if (empty($info) or strpos($info, 'http') === 0) {
 534             $info = get_string('siteyoutube', 'core_media');
 535         }
 536         $info = s($info);
 537
 538         self::pick_video_size($width, $height);
 539
 540         $params = '';
 541         $start = self::get_start_time($url);
 542         if ($start > 0) {
 543             $params .= "start=$start&amp;";
 544         }
 545
 546         $listid = $url->param('list');
 547         // Check for non-empty but valid playlist ID.
 548         if (!empty($listid) && !preg_match('/[^a-zA-Z0-9\-_]/', $listid)) {
 549             // This video is part of a playlist, and we want to embed it as such.
 550             $params .= "list=$listid&amp;";
 551         }
 552
 553         return <<<OET
 554 <span class="mediaplugin mediaplugin_youtube">
 555 <iframe title="$info" width="$width" height="$height"
 556   src="https://www.youtube.com/embed/$videoid?{$params}rel=0&amp;wmode=transparent" frameborder="0" allowfullscreen="1"></iframe>
 557 </span>
 558 OET;
 559
 560     }
 561
 562     /**
 563      * Check for start time parameter.  Note that it's in hours/mins/secs in the URL,
 564      * but the embedded player takes only a number of seconds as the "start" parameter.
 565      * @param moodle_url $url URL of video to be embedded.
 566      * @return int Number of seconds video should start at.
 567      */
 568     protected static function get_start_time($url) {
 569         $matches = array();
 570         $seconds = 0;
 571
 572         $rawtime = $url->param('t');
 573         if (empty($rawtime)) {
 574             $rawtime = $url->param('start');
 575         }
 576
 577         if (is_numeric($rawtime)) {
 578             // Start time already specified as a number of seconds; ensure it's an integer.
 579             $seconds = $rawtime;
 580         } else if (preg_match('/(\d+?h)?(\d+?m)?(\d+?s)?/i', $rawtime, $matches)) {
 581             // Convert into a raw number of seconds, as that's all embedded players accept.
 582             for ($i = 1; $i < count($matches); $i++) {
 583                 if (empty($matches[$i])) {
 584                     continue;
 585                 }
 586                 $part = str_split($matches[$i], strlen($matches[$i]) - 1);
 587                 switch ($part[1]) {
 588                     case 'h':
 589                         $seconds += 3600 * $part[0];
 590                         break;
 591                     case 'm':
 592                         $seconds += 60 * $part[0];
 593                         break;
 594                     default:
 595                         $seconds += $part[0];
 596                 }
 597             }
 598         }
 599
 600         return intval($seconds);
 601     }
 602
 603     protected function get_regex() {
 604         // Regex for standard youtube link
 605          $link = '(youtube(-nocookie)?\.com/(?:watch\?v=|v/))';
 606         // Regex for shortened youtube link
 607         $shortlink = '((youtu|y2u)\.be/)';
 608
 609         // Initial part of link.
 610          $start = '~^https?://(www\.)?(' . $link . '|' . $shortlink . ')';
 611         // Middle bit: Video key value
 612         $middle = '([a-z0-9\-_]+)';
 613         return $start . $middle . core_media_player_external::END_LINK_REGEX_PART;
 614     }
 615
 616     public function get_rank() {
 617         // I decided to make the link-embedding ones (that don't handle file
 618         // formats) have ranking in the 1000 range.
 619         return 1001;
 620     }
 621
 622     public function get_embeddable_markers() {
 623         return array('youtube.com', 'youtube-nocookie.com', 'youtu.be', 'y2u.be');
 624     }
 625 }
 626
 627
 628 /**
 629  * Player that creates YouTube playlist embedding.
 630  *
 631  * @copyright 2011 The Open University
 632  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 633  */
 634 class core_media_player_youtube_playlist extends core_media_player_external {
 635     public function is_enabled() {
 636         global $CFG;
 637         // Use the youtube on/off flag.
 638         return $CFG->core_media_enable_youtube;
 639     }
 640
 641     protected function embed_external(moodle_url $url, $name, $width, $height, $options) {
 642         $site = $this->matches[1];
 643         $playlist = $this->matches[3];
 644
 645         $info = trim($name);
 646         if (empty($info) or strpos($info, 'http') === 0) {
 647             $info = get_string('siteyoutube', 'core_media');
 648         }
 649         $info = s($info);
 650
 651         self::pick_video_size($width, $height);
 652
 653         return <<<OET
 654 <span class="mediaplugin mediaplugin_youtube">
 655 <iframe width="$width" height="$height" src="https://$site/embed/videoseries?list=$playlist" frameborder="0" allowfullscreen="1"></iframe>
 656 </span>
 657 OET;
 658     }
 659
 660     protected function get_regex() {
 661         // Initial part of link.
 662         $start = '~^https?://(www\.youtube(-nocookie)?\.com)/';
 663         // Middle bit: either view_play_list?p= or p/ (doesn't work on youtube) or playlist?list=.
 664         $middle = '(?:view_play_list\?p=|p/|playlist\?list=)([a-z0-9\-_]+)';
 665         return $start . $middle . core_media_player_external::END_LINK_REGEX_PART;
 666     }
 667
 668     public function get_rank() {
 669         // I decided to make the link-embedding ones (that don't handle file
 670         // formats) have ranking in the 1000 range.
 671         return 1000;
 672     }
 673
 674     public function get_embeddable_markers() {
 675         return array('youtube');
 676     }
 677 }
 678
 679
 680 /**
 681  * MP3 player inserted using JavaScript.
 682  *
 683  * @copyright 2011 The Open University
 684  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 685  */
 686 class core_media_player_mp3 extends core_media_player {
 687     public function embed($urls, $name, $width, $height, $options) {
 688         // Use first url (there can actually be only one unless some idiot
 689         // enters two mp3 files as alternatives).
 690         $url = reset($urls);
 691
 692         // Unique id even across different http requests made at the same time
 693         // (for AJAX, iframes).
 694         $id = 'core_media_mp3_' . md5(time() . '_' . rand());
 695
 696         // When Flash or JavaScript are not available only the fallback is displayed,
 697         // using span not div because players are inline elements.
 698         $spanparams = array('id' => $id, 'class' => 'mediaplugin mediaplugin_mp3');
 699         if ($width) {
 700             $spanparams['style'] = 'width: ' . $width . 'px';
 701         }
 702         $output = html_writer::tag('span', core_media_player::PLACEHOLDER, $spanparams);
 703         // We can not use standard JS init because this may be cached
 704         // note: use 'small' size unless embedding in block mode.
 705         $output .= html_writer::script(js_writer::function_call(
 706                 'M.util.add_audio_player', array($id, $url->out(false),
 707                 empty($options[core_media::OPTION_BLOCK]))));
 708
 709         return $output;
 710     }
 711
 712     public function get_supported_extensions() {
 713         return array('mp3');
 714     }
 715
 716     public function get_rank() {
 717         return 80;
 718     }
 719 }
 720
 721
 722 /**
 723  * Flash video player inserted using JavaScript.
 724  *
 725  * @copyright 2011 The Open University
 726  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 727  */
 728 class core_media_player_flv extends core_media_player {
 729     public function embed($urls, $name, $width, $height, $options) {
 730         // Use first url (there can actually be only one unless some idiot
 731         // enters two mp3 files as alternatives).
 732         $url = reset($urls);
 733
 734         // Unique id even across different http requests made at the same time
 735         // (for AJAX, iframes).
 736         $id = 'core_media_flv_' . md5(time() . '_' . rand());
 737
 738         // Compute width and height.
 739         $autosize = false;
 740         if (!$width && !$height) {
 741             $width = CORE_MEDIA_VIDEO_WIDTH;
 742             $height = CORE_MEDIA_VIDEO_HEIGHT;
 743             $autosize = true;
 744         }
 745
 746         // Fallback span (will normally contain link).
 747         $output = html_writer::tag('span', core_media_player::PLACEHOLDER,
 748                 array('id'=>$id, 'class'=>'mediaplugin mediaplugin_flv'));
 749         // We can not use standard JS init because this may be cached.
 750         $output .= html_writer::script(js_writer::function_call(
 751                 'M.util.add_video_player', array($id, addslashes_js($url->out(false)),
 752                 $width, $height, $autosize)));
 753         return $output;
 754     }
 755
 756     public function get_supported_extensions() {
 757         return array('flv', 'f4v');
 758     }
 759
 760     public function get_rank() {
 761         return 70;
 762     }
 763 }
 764
 765
 766 /**
 767  * Embeds Windows Media Player using object tag.
 768  *
 769  * @copyright 2011 The Open University
 770  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 771  */
 772 class core_media_player_wmp extends core_media_player {
 773     public function embed($urls, $name, $width, $height, $options) {
 774         // Get URL (we just use first, probably there is only one).
 775         $firsturl = reset($urls);
 776         $url = $firsturl->out(false);
 777
 778         // Work out width.
 779         if (!$width || !$height) {
 780             // Object tag has default size.
 781             $mpsize = '';
 782             $size = 'width="' . CORE_MEDIA_VIDEO_WIDTH .
 783                     '" height="' . (CORE_MEDIA_VIDEO_HEIGHT+64) . '"';
 784             $autosize = 'true';
 785         } else {
 786             $size = 'width="' . $width . '" height="' . ($height + 15) . '"';
 787             $mpsize = 'width="' . $width . '" height="' . ($height + 64) . '"';
 788             $autosize = 'false';
 789         }
 790
 791         // MIME type for object tag.
 792         $mimetype = core_media::get_mimetype($firsturl);
 793
 794         $fallback = core_media_player::PLACEHOLDER;
 795
 796         // Embed code.
 797         return <<<OET
 798 <span class="mediaplugin mediaplugin_wmp">
 799     <object classid="CLSID:6BF52A52-394A-11d3-B153-00C04F79FAA6" $mpsize
 800             standby="Loading Microsoft(R) Windows(R) Media Player components..."
 801             type="application/x-oleobject">
 802         <param name="Filename" value="$url" />
 803         <param name="src" value="$url" />
 804         <param name="url" value="$url" />
 805         <param name="ShowControls" value="true" />
 806         <param name="AutoRewind" value="true" />
 807         <param name="AutoStart" value="false" />
 808         <param name="Autosize" value="$autosize" />
 809         <param name="EnableContextMenu" value="true" />
 810         <param name="TransparentAtStart" value="false" />
 811         <param name="AnimationAtStart" value="false" />
 812         <param name="ShowGotoBar" value="false" />
 813         <param name="EnableFullScreenControls" value="true" />
 814         <param name="uimode" value="full" />
 815         <!--[if !IE]><!-->
 816         <object data="$url" type="$mimetype" $size>
 817             <param name="src" value="$url" />
 818             <param name="controller" value="true" />
 819             <param name="autoplay" value="false" />
 820             <param name="autostart" value="false" />
 821             <param name="resize" value="scale" />
 822         <!--<![endif]-->
 823             $fallback
 824         <!--[if !IE]><!-->
 825         </object>
 826         <!--<![endif]-->
 827     </object>
 828 </span>
 829 OET;
 830     }
 831
 832     public function get_supported_extensions() {
 833         return array('wmv', 'avi');
 834     }
 835
 836     public function get_rank() {
 837         return 60;
 838     }
 839 }
 840
 841
 842 /**
 843  * Media player using object tag and QuickTime player.
 844  *
 845  * @copyright 2011 The Open University
 846  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 847  */
 848 class core_media_player_qt extends core_media_player {
 849     public function embed($urls, $name, $width, $height, $options) {
 850         // Show first URL.
 851         $firsturl = reset($urls);
 852         $url = $firsturl->out(true);
 853
 854         // Work out size.
 855         if (!$width || !$height) {
 856             $size = 'width="' . CORE_MEDIA_VIDEO_WIDTH .
 857                     '" height="' . (CORE_MEDIA_VIDEO_HEIGHT + 15) . '"';
 858         } else {
 859             $size = 'width="' . $width . '" height="' . ($height + 15) . '"';
 860         }
 861
 862         // MIME type for object tag.
 863         $mimetype = core_media::get_mimetype($firsturl);
 864
 865         $fallback = core_media_player::PLACEHOLDER;
 866
 867         // Embed code.
 868         return <<<OET
 869 <span class="mediaplugin mediaplugin_qt">
 870     <object classid="clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B"
 871             codebase="http://www.apple.com/qtactivex/qtplugin.cab" $size>
 872         <param name="pluginspage" value="http://www.apple.com/quicktime/download/" />
 873         <param name="src" value="$url" />
 874         <param name="controller" value="true" />
 875         <param name="loop" value="false" />
 876         <param name="autoplay" value="false" />
 877         <param name="autostart" value="false" />
 878         <param name="scale" value="aspect" />
 879         <!--[if !IE]><!-->
 880         <object data="$url" type="$mimetype" $size>
 881             <param name="src" value="$url" />
 882             <param name="pluginurl" value="http://www.apple.com/quicktime/download/" />
 883             <param name="controller" value="true" />
 884             <param name="loop" value="false" />
 885             <param name="autoplay" value="false" />
 886             <param name="autostart" value="false" />
 887             <param name="scale" value="aspect" />
 888         <!--<![endif]-->
 889             $fallback
 890         <!--[if !IE]><!-->
 891         </object>
 892         <!--<![endif]-->
 893     </object>
 894 </span>
 895 OET;
 896     }
 897
 898     public function get_supported_extensions() {
 899         return array('mpg', 'mpeg', 'mov', 'mp4', 'm4v', 'm4a');
 900     }
 901
 902     public function get_rank() {
 903         return 10;
 904     }
 905 }
 906
 907
 908 /**
 909  * Media player using object tag and RealPlayer.
 910  *
 911  * Hopefully nobody is using this obsolete format any more!
 912  *
 913  * @copyright 2011 The Open University
 914  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 915  */
 916 class core_media_player_rm extends core_media_player {
 917     public function embed($urls, $name, $width, $height, $options) {
 918         // Show first URL.
 919         $firsturl = reset($urls);
 920         $url = $firsturl->out(true);
 921
 922         // Get name to use as title.
 923         $info = s($this->get_name($name, $urls));
 924
 925         // The previous version of this code has the following comment, which
 926         // I don't understand, but trust it is correct:
 927         // Note: the size is hardcoded intentionally because this does not work anyway!
 928         $width = CORE_MEDIA_VIDEO_WIDTH;
 929         $height = CORE_MEDIA_VIDEO_HEIGHT;
 930
 931         $fallback = core_media_player::PLACEHOLDER;
 932         return <<<OET
 933 <span class="mediaplugin mediaplugin_real">
 934     <object title="$info" classid="clsid:CFCDAA03-8BE4-11cf-B84B-0020AFBBCCFA"
 935             data="$url" width="$width" height="$height"">
 936         <param name="src" value="$url" />
 937         <param name="controls" value="All" />
 938         <!--[if !IE]><!-->
 939         <object title="$info" type="audio/x-pn-realaudio-plugin"
 940                 data="$url" width="$width" height="$height">
 941             <param name="src" value="$url" />
 942             <param name="controls" value="All" />
 943         <!--<![endif]-->
 944             $fallback
 945         <!--[if !IE]><!-->
 946         </object>
 947         <!--<![endif]-->
 948   </object>
 949 </span>
 950 OET;
 951     }
 952
 953     public function get_supported_extensions() {
 954         return array('ra', 'ram', 'rm', 'rv');
 955     }
 956
 957     public function get_rank() {
 958         return 40;
 959     }
 960 }
 961
 962
 963 /**
 964  * Media player for Flash SWF files.
 965  *
 966  * This player contains additional security restriction: it will only be used
 967  * if you add option core_media_player_swf::ALLOW = true.
 968  *
 969  * Code should only set this option if it has verified that the data was
 970  * embedded by a trusted user (e.g. in trust text).
 971  *
 972  * @copyright 2011 The Open University
 973  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 974  */
 975 class core_media_player_swf extends core_media_player {
 976     public function embed($urls, $name, $width, $height, $options) {
 977         self::pick_video_size($width, $height);
 978
 979         $firsturl = reset($urls);
 980         $url = $firsturl->out(true);
 981
 982         $fallback = core_media_player::PLACEHOLDER;
 983         $output = <<<OET
 984 <span class="mediaplugin mediaplugin_swf">
 985   <object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="$width" height="$height">
 986     <param name="movie" value="$url" />
 987     <param name="autoplay" value="true" />
 988     <param name="loop" value="false" />
 989     <param name="controller" value="true" />
 990     <param name="scale" value="aspect" />
 991     <param name="base" value="." />
 992     <param name="allowscriptaccess" value="never" />
 993     <param name="allowfullscreen" value="true" />
 994 <!--[if !IE]><!-->
 995     <object type="application/x-shockwave-flash" data="$url" width="$width" height="$height">
 996       <param name="controller" value="true" />
 997       <param name="autoplay" value="true" />
 998       <param name="loop" value="false" />
 999       <param name="scale" value="aspect" />
1000       <param name="base" value="." />
1001       <param name="allowscriptaccess" value="never" />
1002       <param name="allowfullscreen" value="true" />
1003 <!--<![endif]-->
1004 $fallback
1005 <!--[if !IE]><!-->
1006     </object>
1007 <!--<![endif]-->
1008   </object>
1009 </span>
1010 OET;
1011
1012         return $output;
1013     }
1014
1015     public function get_supported_extensions() {
1016         return array('swf');
1017     }
1018
1019     public function list_supported_urls(array $urls, array $options = array()) {
1020         // Not supported unless the creator is trusted.
1021         if (empty($options[core_media::OPTION_TRUSTED])) {
1022             return array();
1023         }
1024         return parent::list_supported_urls($urls, $options);
1025     }
1026
1027     public function get_rank() {
1028         return 30;
1029     }
1030 }
1031
1032
1033 /**
1034  * Player that creates HTML5 <video> tag.
1035  *
1036  * @copyright 2011 The Open University
1037  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1038  */
1039 class core_media_player_html5video extends core_media_player {
1040     public function embed($urls, $name, $width, $height, $options) {
1041         // Special handling to make videos play on Android devices pre 2.3.
1042         // Note: I tested and 2.3.3 (in emulator) works without, is 533.1 webkit.
1043         $oldandroid = core_useragent::is_webkit_android() &&
1044                 !core_useragent::check_webkit_android_version('533.1');
1045
1046         // Build array of source tags.
1047         $sources = array();
1048         foreach ($urls as $url) {
1049             $mimetype = core_media::get_mimetype($url);
1050             $source = html_writer::tag('source', '', array('src' => $url, 'type' => $mimetype));
1051             if ($mimetype === 'video/mp4') {
1052                 if ($oldandroid) {
1053                     // Old Android fails if you specify the type param.
1054                     $source = html_writer::tag('source', '', array('src' => $url));
1055                 }
1056
1057                 // Better add m4v as first source, it might be a bit more
1058                 // compatible with problematic browsers.
1059                 array_unshift($sources, $source);
1060             } else {
1061                 $sources[] = $source;
1062             }
1063         }
1064
1065         $sources = implode("\n", $sources);
1066         $title = s($this->get_name($name, $urls));
1067
1068         if (!$width) {
1069             // No width specified, use system default.
1070             $width = CORE_MEDIA_VIDEO_WIDTH;
1071         }
1072
1073         if (!$height) {
1074             // Let browser choose height automatically.
1075             $size = "width=\"$width\"";
1076         } else {
1077             $size = "width=\"$width\" height=\"$height\"";
1078         }
1079
1080         $sillyscript = '';
1081         $idtag = '';
1082         if ($oldandroid) {
1083             // Old Android does not support 'controls' option.
1084             $id = 'core_media_html5v_' . md5(time() . '_' . rand());
1085             $idtag = 'id="' . $id . '"';
1086             $sillyscript = <<<OET
1087 <script type="text/javascript">
1088 document.getElementById('$id').addEventListener('click', function() {
1089     this.play();
1090 }, false);
1091 </script>
1092 OET;
1093         }
1094
1095         $fallback = core_media_player::PLACEHOLDER;
1096         return <<<OET
1097 <span class="mediaplugin mediaplugin_html5video">
1098 <video $idtag controls="true" $size preload="metadata" title="$title">
1099     $sources
1100     $fallback
1101 </video>
1102 $sillyscript
1103 </span>
1104 OET;
1105     }
1106
1107     public function get_supported_extensions() {
1108         return array('m4v', 'webm', 'ogv', 'mp4');
1109     }
1110
1111     public function list_supported_urls(array $urls, array $options = array()) {
1112         $extensions = $this->get_supported_extensions();
1113         $result = array();
1114         foreach ($urls as $url) {
1115             $ext = core_media::get_extension($url);
1116             if (in_array($ext, $extensions)) {
1117                 // Unfortunately html5 video does not handle fallback properly.
1118                 // https://www.w3.org/Bugs/Public/show_bug.cgi?id=10975
1119                 // That means we need to do browser detect and not use html5 on
1120                 // browsers which do not support the given type, otherwise users
1121                 // will not even see the fallback link.
1122                 // Based on http://en.wikipedia.org/wiki/HTML5_video#Table - this
1123                 // is a simplified version, does not take into account old browser
1124                 // versions or manual plugins.
1125                 if ($ext === 'ogv' || $ext === 'webm') {
1126                     // Formats .ogv and .webm are not supported in IE, Edge or Safari.
1127                     if (core_useragent::is_ie() || core_useragent::is_edge() || core_useragent::is_safari()) {
1128                         continue;
1129                     }
1130                 } else {
1131                     // Formats .m4v and .mp4 are not supported in Opera, or in Firefox before 27.
1132                     // https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats
1133                     // has the details.
1134                     if (core_useragent::is_opera() || (core_useragent::is_firefox() &&
1135                             !core_useragent::check_firefox_version(27))) {
1136                         continue;
1137                     }
1138                 }
1139
1140                 $result[] = $url;
1141             }
1142         }
1143         return $result;
1144     }
1145
1146     public function get_rank() {
1147         return 50;
1148     }
1149 }
1150
1151
1152 /**
1153  * Player that creates HTML5 <audio> tag.
1154  *
1155  * @copyright 2011 The Open University
1156  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1157  */
1158 class core_media_player_html5audio extends core_media_player {
1159     public function embed($urls, $name, $width, $height, $options) {
1160
1161         // Build array of source tags.
1162         $sources = array();
1163         foreach ($urls as $url) {
1164             $mimetype = core_media::get_mimetype($url);
1165             $sources[] = html_writer::tag('source', '', array('src' => $url, 'type' => $mimetype));
1166         }
1167
1168         $sources = implode("\n", $sources);
1169         $title = s($this->get_name($name, $urls));
1170
1171         // Default to not specify size (so it can be changed in css).
1172         $size = '';
1173         if ($width) {
1174             $size = 'width="' . $width . '"';
1175         }
1176
1177         $fallback = core_media_player::PLACEHOLDER;
1178
1179         return <<<OET
1180 <audio controls="true" $size class="mediaplugin mediaplugin_html5audio" preload="none" title="$title">
1181 $sources
1182 $fallback
1183 </audio>
1184 OET;
1185     }
1186
1187     public function get_supported_extensions() {
1188         return array('ogg', 'oga', 'aac', 'm4a', 'mp3');
1189     }
1190
1191     public function list_supported_urls(array $urls, array $options = array()) {
1192         $extensions = $this->get_supported_extensions();
1193         $result = array();
1194         foreach ($urls as $url) {
1195             $ext = core_media::get_extension($url);
1196             if (in_array($ext, $extensions)) {
1197                 if ($ext === 'ogg' || $ext === 'oga') {
1198                     // Formats .ogg and .oga are not supported in IE, Edge, or Safari.
1199                     if (core_useragent::is_ie() || core_useragent::is_edge() || core_useragent::is_safari()) {
1200                         continue;
1201                     }
1202                 } else {
1203                     // Formats .aac, .mp3, and .m4a are not supported in Opera.
1204                     if (core_useragent::is_opera()) {
1205                         continue;
1206                     }
1207                     // Formats .mp3 and .m4a were not reliably supported in Firefox before 27.
1208                     // https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats
1209                     // has the details. .aac is still not supported.
1210                     if (core_useragent::is_firefox() && ($ext === 'aac' ||
1211                             !core_useragent::check_firefox_version(27))) {
1212                         continue;
1213                     }
1214                 }
1215                 // Old Android versions (pre 2.3.3) 'support' audio tag but no codecs.
1216                 if (core_useragent::is_webkit_android() &&
1217                         !core_useragent::is_webkit_android('533.1')) {
1218                     continue;
1219                 }
1220
1221                 $result[] = $url;
1222             }
1223         }
1224         return $result;
1225     }
1226
1227     public function get_rank() {
1228         return 20;
1229     }
1230 }
1231
1232
1233 /**
1234  * Special media player class that just puts a link.
1235  *
1236  * Always enabled, used as the last fallback.
1237  *
1238  * @copyright 2011 The Open University
1239  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1240  */
1241 class core_media_player_link extends core_media_player {
1242     public function embed($urls, $name, $width, $height, $options) {
1243         // If link is turned off, return empty.
1244         if (!empty($options[core_media::OPTION_NO_LINK])) {
1245             return '';
1246         }
1247
1248         // Build up link content.
1249         $output = '';
1250         foreach ($urls as $url) {
1251             $title = core_media::get_filename($url);
1252             $printlink = html_writer::link($url, $title, array('class' => 'mediafallbacklink'));
1253             if ($output) {
1254                 // Where there are multiple available formats, there are fallback links
1255                 // for all formats, separated by /.
1256                 $output .= ' / ';
1257             }
1258             $output .= $printlink;
1259         }
1260         return $output;
1261     }
1262
1263     public function list_supported_urls(array $urls, array $options = array()) {
1264         // Supports all URLs.
1265         return $urls;
1266     }
1267
1268     public function is_enabled() {
1269         // Cannot be disabled.
1270         return true;
1271     }
1272
1273     public function get_rank() {
1274         return 0;
1275     }
1276 }