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"></iframe>
 498 </span>
 499 OET;
 500
 501         return $output;
 502     }
 503
 504     protected function get_regex() {
 505         // Initial part of link.
 506         $start = '~^https?://vimeo\.com/';
 507         // Middle bit: either watch?v= or v/.
 508         $middle = '([0-9]+)';
 509         return $start . $middle . core_media_player_external::END_LINK_REGEX_PART;
 510     }
 511
 512     public function get_rank() {
 513         return 1010;
 514     }
 515
 516     public function get_embeddable_markers() {
 517         return array('vimeo.com/');
 518     }
 519 }
 520
 521 /**
 522  * Player that creates YouTube embedding.
 523  *
 524  * @copyright 2011 The Open University
 525  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 526  */
 527 class core_media_player_youtube extends core_media_player_external {
 528     protected function embed_external(moodle_url $url, $name, $width, $height, $options) {
 529         $videoid = end($this->matches);
 530
 531         $info = trim($name);
 532         if (empty($info) or strpos($info, 'http') === 0) {
 533             $info = get_string('siteyoutube', 'core_media');
 534         }
 535         $info = s($info);
 536
 537         self::pick_video_size($width, $height);
 538
 539         return <<<OET
 540 <span class="mediaplugin mediaplugin_youtube">
 541 <iframe title="$info" width="$width" height="$height"
 542   src="https://www.youtube.com/embed/$videoid?rel=0&wmode=transparent" frameborder="0" allowfullscreen="1"></iframe>
 543 </span>
 544 OET;
 545
 546     }
 547
 548     protected function get_regex() {
 549         // Regex for standard youtube link
 550          $link = '(youtube(-nocookie)?\.com/(?:watch\?v=|v/))';
 551         // Regex for shortened youtube link
 552         $shortlink = '((youtu|y2u)\.be/)';
 553
 554         // Initial part of link.
 555          $start = '~^https?://(www\.)?(' . $link . '|' . $shortlink . ')';
 556         // Middle bit: Video key value
 557         $middle = '([a-z0-9\-_]+)';
 558         return $start . $middle . core_media_player_external::END_LINK_REGEX_PART;
 559     }
 560
 561     public function get_rank() {
 562         // I decided to make the link-embedding ones (that don't handle file
 563         // formats) have ranking in the 1000 range.
 564         return 1001;
 565     }
 566
 567     public function get_embeddable_markers() {
 568         return array('youtube.com', 'youtube-nocookie.com', 'youtu.be', 'y2u.be');
 569     }
 570 }
 571
 572
 573 /**
 574  * Player that creates YouTube playlist embedding.
 575  *
 576  * @copyright 2011 The Open University
 577  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 578  */
 579 class core_media_player_youtube_playlist extends core_media_player_external {
 580     public function is_enabled() {
 581         global $CFG;
 582         // Use the youtube on/off flag.
 583         return $CFG->core_media_enable_youtube;
 584     }
 585
 586     protected function embed_external(moodle_url $url, $name, $width, $height, $options) {
 587         $site = $this->matches[1];
 588         $playlist = $this->matches[3];
 589
 590         $info = trim($name);
 591         if (empty($info) or strpos($info, 'http') === 0) {
 592             $info = get_string('siteyoutube', 'core_media');
 593         }
 594         $info = s($info);
 595
 596         self::pick_video_size($width, $height);
 597
 598         return <<<OET
 599 <span class="mediaplugin mediaplugin_youtube">
 600 <iframe width="$width" height="$height" src="https://$site/embed/videoseries?list=$playlist" frameborder="0" allowfullscreen="1"></iframe>
 601 </span>
 602 OET;
 603     }
 604
 605     protected function get_regex() {
 606         // Initial part of link.
 607         $start = '~^https?://(www\.youtube(-nocookie)?\.com)/';
 608         // Middle bit: either view_play_list?p= or p/ (doesn't work on youtube) or playlist?list=.
 609         $middle = '(?:view_play_list\?p=|p/|playlist\?list=)([a-z0-9\-_]+)';
 610         return $start . $middle . core_media_player_external::END_LINK_REGEX_PART;
 611     }
 612
 613     public function get_rank() {
 614         // I decided to make the link-embedding ones (that don't handle file
 615         // formats) have ranking in the 1000 range.
 616         return 1000;
 617     }
 618
 619     public function get_embeddable_markers() {
 620         return array('youtube');
 621     }
 622 }
 623
 624
 625 /**
 626  * MP3 player inserted using JavaScript.
 627  *
 628  * @copyright 2011 The Open University
 629  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 630  */
 631 class core_media_player_mp3 extends core_media_player {
 632     public function embed($urls, $name, $width, $height, $options) {
 633         // Use first url (there can actually be only one unless some idiot
 634         // enters two mp3 files as alternatives).
 635         $url = reset($urls);
 636
 637         // Unique id even across different http requests made at the same time
 638         // (for AJAX, iframes).
 639         $id = 'core_media_mp3_' . md5(time() . '_' . rand());
 640
 641         // When Flash or JavaScript are not available only the fallback is displayed,
 642         // using span not div because players are inline elements.
 643         $spanparams = array('id' => $id, 'class' => 'mediaplugin mediaplugin_mp3');
 644         if ($width) {
 645             $spanparams['style'] = 'width: ' . $width . 'px';
 646         }
 647         $output = html_writer::tag('span', core_media_player::PLACEHOLDER, $spanparams);
 648         // We can not use standard JS init because this may be cached
 649         // note: use 'small' size unless embedding in block mode.
 650         $output .= html_writer::script(js_writer::function_call(
 651                 'M.util.add_audio_player', array($id, $url->out(false),
 652                 empty($options[core_media::OPTION_BLOCK]))));
 653
 654         return $output;
 655     }
 656
 657     public function get_supported_extensions() {
 658         return array('mp3');
 659     }
 660
 661     public function get_rank() {
 662         return 80;
 663     }
 664 }
 665
 666
 667 /**
 668  * Flash video player inserted using JavaScript.
 669  *
 670  * @copyright 2011 The Open University
 671  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 672  */
 673 class core_media_player_flv extends core_media_player {
 674     public function embed($urls, $name, $width, $height, $options) {
 675         // Use first url (there can actually be only one unless some idiot
 676         // enters two mp3 files as alternatives).
 677         $url = reset($urls);
 678
 679         // Unique id even across different http requests made at the same time
 680         // (for AJAX, iframes).
 681         $id = 'core_media_flv_' . md5(time() . '_' . rand());
 682
 683         // Compute width and height.
 684         $autosize = false;
 685         if (!$width && !$height) {
 686             $width = CORE_MEDIA_VIDEO_WIDTH;
 687             $height = CORE_MEDIA_VIDEO_HEIGHT;
 688             $autosize = true;
 689         }
 690
 691         // Fallback span (will normally contain link).
 692         $output = html_writer::tag('span', core_media_player::PLACEHOLDER,
 693                 array('id'=>$id, 'class'=>'mediaplugin mediaplugin_flv'));
 694         // We can not use standard JS init because this may be cached.
 695         $output .= html_writer::script(js_writer::function_call(
 696                 'M.util.add_video_player', array($id, addslashes_js($url->out(false)),
 697                 $width, $height, $autosize)));
 698         return $output;
 699     }
 700
 701     public function get_supported_extensions() {
 702         return array('flv', 'f4v');
 703     }
 704
 705     public function get_rank() {
 706         return 70;
 707     }
 708 }
 709
 710
 711 /**
 712  * Embeds Windows Media Player using object tag.
 713  *
 714  * @copyright 2011 The Open University
 715  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 716  */
 717 class core_media_player_wmp extends core_media_player {
 718     public function embed($urls, $name, $width, $height, $options) {
 719         // Get URL (we just use first, probably there is only one).
 720         $firsturl = reset($urls);
 721         $url = $firsturl->out(false);
 722
 723         // Work out width.
 724         if (!$width || !$height) {
 725             // Object tag has default size.
 726             $mpsize = '';
 727             $size = 'width="' . CORE_MEDIA_VIDEO_WIDTH .
 728                     '" height="' . (CORE_MEDIA_VIDEO_HEIGHT+64) . '"';
 729             $autosize = 'true';
 730         } else {
 731             $size = 'width="' . $width . '" height="' . ($height + 15) . '"';
 732             $mpsize = 'width="' . $width . '" height="' . ($height + 64) . '"';
 733             $autosize = 'false';
 734         }
 735
 736         // MIME type for object tag.
 737         $mimetype = core_media::get_mimetype($firsturl);
 738
 739         $fallback = core_media_player::PLACEHOLDER;
 740
 741         // Embed code.
 742         return <<<OET
 743 <span class="mediaplugin mediaplugin_wmp">
 744     <object classid="CLSID:6BF52A52-394A-11d3-B153-00C04F79FAA6" $mpsize
 745             standby="Loading Microsoft(R) Windows(R) Media Player components..."
 746             type="application/x-oleobject">
 747         <param name="Filename" value="$url" />
 748         <param name="src" value="$url" />
 749         <param name="url" value="$url" />
 750         <param name="ShowControls" value="true" />
 751         <param name="AutoRewind" value="true" />
 752         <param name="AutoStart" value="false" />
 753         <param name="Autosize" value="$autosize" />
 754         <param name="EnableContextMenu" value="true" />
 755         <param name="TransparentAtStart" value="false" />
 756         <param name="AnimationAtStart" value="false" />
 757         <param name="ShowGotoBar" value="false" />
 758         <param name="EnableFullScreenControls" value="true" />
 759         <param name="uimode" value="full" />
 760         <!--[if !IE]>-->
 761         <object data="$url" type="$mimetype" $size>
 762             <param name="src" value="$url" />
 763             <param name="controller" value="true" />
 764             <param name="autoplay" value="false" />
 765             <param name="autostart" value="false" />
 766             <param name="resize" value="scale" />
 767         <!--<![endif]-->
 768             $fallback
 769         <!--[if !IE]>-->
 770         </object>
 771         <!--<![endif]-->
 772     </object>
 773 </span>
 774 OET;
 775     }
 776
 777     public function get_supported_extensions() {
 778         return array('wmv', 'avi');
 779     }
 780
 781     public function get_rank() {
 782         return 60;
 783     }
 784 }
 785
 786
 787 /**
 788  * Media player using object tag and QuickTime player.
 789  *
 790  * @copyright 2011 The Open University
 791  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 792  */
 793 class core_media_player_qt extends core_media_player {
 794     public function embed($urls, $name, $width, $height, $options) {
 795         // Show first URL.
 796         $firsturl = reset($urls);
 797         $url = $firsturl->out(true);
 798
 799         // Work out size.
 800         if (!$width || !$height) {
 801             $size = 'width="' . CORE_MEDIA_VIDEO_WIDTH .
 802                     '" height="' . (CORE_MEDIA_VIDEO_HEIGHT + 15) . '"';
 803         } else {
 804             $size = 'width="' . $width . '" height="' . ($height + 15) . '"';
 805         }
 806
 807         // MIME type for object tag.
 808         $mimetype = core_media::get_mimetype($firsturl);
 809
 810         $fallback = core_media_player::PLACEHOLDER;
 811
 812         // Embed code.
 813         return <<<OET
 814 <span class="mediaplugin mediaplugin_qt">
 815     <object classid="clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B"
 816             codebase="http://www.apple.com/qtactivex/qtplugin.cab" $size>
 817         <param name="pluginspage" value="http://www.apple.com/quicktime/download/" />
 818         <param name="src" value="$url" />
 819         <param name="controller" value="true" />
 820         <param name="loop" value="false" />
 821         <param name="autoplay" value="false" />
 822         <param name="autostart" value="false" />
 823         <param name="scale" value="aspect" />
 824         <!--[if !IE]>-->
 825         <object data="$url" type="$mimetype" $size>
 826             <param name="src" value="$url" />
 827             <param name="pluginurl" value="http://www.apple.com/quicktime/download/" />
 828             <param name="controller" value="true" />
 829             <param name="loop" value="false" />
 830             <param name="autoplay" value="false" />
 831             <param name="autostart" value="false" />
 832             <param name="scale" value="aspect" />
 833         <!--<![endif]-->
 834             $fallback
 835         <!--[if !IE]>-->
 836         </object>
 837         <!--<![endif]-->
 838     </object>
 839 </span>
 840 OET;
 841     }
 842
 843     public function get_supported_extensions() {
 844         return array('mpg', 'mpeg', 'mov', 'mp4', 'm4v', 'm4a');
 845     }
 846
 847     public function get_rank() {
 848         return 50;
 849     }
 850 }
 851
 852
 853 /**
 854  * Media player using object tag and RealPlayer.
 855  *
 856  * Hopefully nobody is using this obsolete format any more!
 857  *
 858  * @copyright 2011 The Open University
 859  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 860  */
 861 class core_media_player_rm extends core_media_player {
 862     public function embed($urls, $name, $width, $height, $options) {
 863         // Show first URL.
 864         $firsturl = reset($urls);
 865         $url = $firsturl->out(true);
 866
 867         // Get name to use as title.
 868         $info = s($this->get_name($name, $urls));
 869
 870         // The previous version of this code has the following comment, which
 871         // I don't understand, but trust it is correct:
 872         // Note: the size is hardcoded intentionally because this does not work anyway!
 873         $width = CORE_MEDIA_VIDEO_WIDTH;
 874         $height = CORE_MEDIA_VIDEO_HEIGHT;
 875
 876         $fallback = core_media_player::PLACEHOLDER;
 877         return <<<OET
 878 <span class="mediaplugin mediaplugin_real">
 879     <object title="$info" classid="clsid:CFCDAA03-8BE4-11cf-B84B-0020AFBBCCFA"
 880             data="$url" width="$width" height="$height"">
 881         <param name="src" value="$url" />
 882         <param name="controls" value="All" />
 883         <!--[if !IE]>-->
 884         <object title="$info" type="audio/x-pn-realaudio-plugin"
 885                 data="$url" width="$width" height="$height">
 886             <param name="src" value="$url" />
 887             <param name="controls" value="All" />
 888         <!--<![endif]-->
 889             $fallback
 890         <!--[if !IE]>-->
 891         </object>
 892         <!--<![endif]-->
 893   </object>
 894 </span>
 895 OET;
 896     }
 897
 898     public function get_supported_extensions() {
 899         return array('ra', 'ram', 'rm', 'rv');
 900     }
 901
 902     public function get_rank() {
 903         return 40;
 904     }
 905 }
 906
 907
 908 /**
 909  * Media player for Flash SWF files.
 910  *
 911  * This player contains additional security restriction: it will only be used
 912  * if you add option core_media_player_swf::ALLOW = true.
 913  *
 914  * Code should only set this option if it has verified that the data was
 915  * embedded by a trusted user (e.g. in trust text).
 916  *
 917  * @copyright 2011 The Open University
 918  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 919  */
 920 class core_media_player_swf extends core_media_player {
 921     public function embed($urls, $name, $width, $height, $options) {
 922         self::pick_video_size($width, $height);
 923
 924         $firsturl = reset($urls);
 925         $url = $firsturl->out(true);
 926
 927         $fallback = core_media_player::PLACEHOLDER;
 928         $output = <<<OET
 929 <span class="mediaplugin mediaplugin_swf">
 930   <object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="$width" height="$height">
 931     <param name="movie" value="$url" />
 932     <param name="autoplay" value="true" />
 933     <param name="loop" value="false" />
 934     <param name="controller" value="true" />
 935     <param name="scale" value="aspect" />
 936     <param name="base" value="." />
 937     <param name="allowscriptaccess" value="never" />
 938 <!--[if !IE]>-->
 939     <object type="application/x-shockwave-flash" data="$url" width="$width" height="$height">
 940       <param name="controller" value="true" />
 941       <param name="autoplay" value="true" />
 942       <param name="loop" value="false" />
 943       <param name="scale" value="aspect" />
 944       <param name="base" value="." />
 945       <param name="allowscriptaccess" value="never" />
 946 <!--<![endif]-->
 947 $fallback
 948 <!--[if !IE]>-->
 949     </object>
 950 <!--<![endif]-->
 951   </object>
 952 </span>
 953 OET;
 954
 955         return $output;
 956     }
 957
 958     public function get_supported_extensions() {
 959         return array('swf');
 960     }
 961
 962     public function list_supported_urls(array $urls, array $options = array()) {
 963         // Not supported unless the creator is trusted.
 964         if (empty($options[core_media::OPTION_TRUSTED])) {
 965             return array();
 966         }
 967         return parent::list_supported_urls($urls, $options);
 968     }
 969
 970     public function get_rank() {
 971         return 30;
 972     }
 973 }
 974
 975
 976 /**
 977  * Player that creates HTML5 <video> tag.
 978  *
 979  * @copyright 2011 The Open University
 980  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 981  */
 982 class core_media_player_html5video extends core_media_player {
 983     public function embed($urls, $name, $width, $height, $options) {
 984         // Special handling to make videos play on Android devices pre 2.3.
 985         // Note: I tested and 2.3.3 (in emulator) works without, is 533.1 webkit.
 986         $oldandroid = core_useragent::is_webkit_android() &&
 987                 !core_useragent::check_webkit_android_version('533.1');
 988
 989         // Build array of source tags.
 990         $sources = array();
 991         foreach ($urls as $url) {
 992             $mimetype = core_media::get_mimetype($url);
 993             $source = html_writer::tag('source', '', array('src' => $url, 'type' => $mimetype));
 994             if ($mimetype === 'video/mp4') {
 995                 if ($oldandroid) {
 996                     // Old Android fails if you specify the type param.
 997                     $source = html_writer::tag('source', '', array('src' => $url));
 998                 }
 999
1000                 // Better add m4v as first source, it might be a bit more
1001                 // compatible with problematic browsers.
1002                 array_unshift($sources, $source);
1003             } else {
1004                 $sources[] = $source;
1005             }
1006         }
1007
1008         $sources = implode("\n", $sources);
1009         $title = s($this->get_name($name, $urls));
1010
1011         if (!$width) {
1012             // No width specified, use system default.
1013             $width = CORE_MEDIA_VIDEO_WIDTH;
1014         }
1015
1016         if (!$height) {
1017             // Let browser choose height automatically.
1018             $size = "width=\"$width\"";
1019         } else {
1020             $size = "width=\"$width\" height=\"$height\"";
1021         }
1022
1023         $sillyscript = '';
1024         $idtag = '';
1025         if ($oldandroid) {
1026             // Old Android does not support 'controls' option.
1027             $id = 'core_media_html5v_' . md5(time() . '_' . rand());
1028             $idtag = 'id="' . $id . '"';
1029             $sillyscript = <<<OET
1030 <script type="text/javascript">
1031 document.getElementById('$id').addEventListener('click', function() {
1032     this.play();
1033 }, false);
1034 </script>
1035 OET;
1036         }
1037
1038         $fallback = core_media_player::PLACEHOLDER;
1039         return <<<OET
1040 <span class="mediaplugin mediaplugin_html5video">
1041 <video $idtag controls="true" $size preload="metadata" title="$title">
1042     $sources
1043     $fallback
1044 </video>
1045 $sillyscript
1046 </span>
1047 OET;
1048     }
1049
1050     public function get_supported_extensions() {
1051         return array('m4v', 'webm', 'ogv', 'mp4');
1052     }
1053
1054     public function list_supported_urls(array $urls, array $options = array()) {
1055         $extensions = $this->get_supported_extensions();
1056         $result = array();
1057         foreach ($urls as $url) {
1058             $ext = core_media::get_extension($url);
1059             if (in_array($ext, $extensions)) {
1060                 // Unfortunately html5 video does not handle fallback properly.
1061                 // https://www.w3.org/Bugs/Public/show_bug.cgi?id=10975
1062                 // That means we need to do browser detect and not use html5 on
1063                 // browsers which do not support the given type, otherwise users
1064                 // will not even see the fallback link.
1065                 // Based on http://en.wikipedia.org/wiki/HTML5_video#Table - this
1066                 // is a simplified version, does not take into account old browser
1067                 // versions or manual plugins.
1068                 if ($ext === 'ogv' || $ext === 'webm') {
1069                     // Formats .ogv and .webm are not supported in IE or Safari.
1070                     if (core_useragent::is_ie() || core_useragent::is_safari()) {
1071                         continue;
1072                     }
1073                 } else {
1074                     // Formats .m4v and .mp4 are not supported in Opera, or in Firefox before 27.
1075                     // https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats
1076                     // has the details.
1077                     if (core_useragent::is_opera() || (core_useragent::is_firefox() &&
1078                             !core_useragent::check_firefox_version(27))) {
1079                         continue;
1080                     }
1081                 }
1082
1083                 $result[] = $url;
1084             }
1085         }
1086         return $result;
1087     }
1088
1089     public function get_rank() {
1090         return 20;
1091     }
1092 }
1093
1094
1095 /**
1096  * Player that creates HTML5 <audio> tag.
1097  *
1098  * @copyright 2011 The Open University
1099  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1100  */
1101 class core_media_player_html5audio extends core_media_player {
1102     public function embed($urls, $name, $width, $height, $options) {
1103
1104         // Build array of source tags.
1105         $sources = array();
1106         foreach ($urls as $url) {
1107             $mimetype = core_media::get_mimetype($url);
1108             $sources[] = html_writer::tag('source', '', array('src' => $url, 'type' => $mimetype));
1109         }
1110
1111         $sources = implode("\n", $sources);
1112         $title = s($this->get_name($name, $urls));
1113
1114         // Default to not specify size (so it can be changed in css).
1115         $size = '';
1116         if ($width) {
1117             $size = 'width="' . $width . '"';
1118         }
1119
1120         $fallback = core_media_player::PLACEHOLDER;
1121
1122         return <<<OET
1123 <audio controls="true" $size class="mediaplugin mediaplugin_html5audio" preload="no" title="$title">
1124 $sources
1125 $fallback
1126 </audio>
1127 OET;
1128     }
1129
1130     public function get_supported_extensions() {
1131         return array('ogg', 'oga', 'aac', 'm4a', 'mp3');
1132     }
1133
1134     public function list_supported_urls(array $urls, array $options = array()) {
1135         $extensions = $this->get_supported_extensions();
1136         $result = array();
1137         foreach ($urls as $url) {
1138             $ext = core_media::get_extension($url);
1139             if (in_array($ext, $extensions)) {
1140                 if ($ext === 'ogg' || $ext === 'oga') {
1141                     // Formats .ogg and .oga are not supported in IE or Safari.
1142                     if (core_useragent::is_ie() || core_useragent::is_safari()) {
1143                         continue;
1144                     }
1145                 } else {
1146                     // Formats .aac, .mp3, and .m4a are not supported in Opera.
1147                     if (core_useragent::is_opera()) {
1148                         continue;
1149                     }
1150                     // Formats .mp3 and .m4a were not reliably supported in Firefox before 27.
1151                     // https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats
1152                     // has the details. .aac is still not supported.
1153                     if (core_useragent::is_firefox() && ($ext === 'aac' ||
1154                             !core_useragent::check_firefox_version(27))) {
1155                         continue;
1156                     }
1157                 }
1158                 // Old Android versions (pre 2.3.3) 'support' audio tag but no codecs.
1159                 if (core_useragent::is_webkit_android() &&
1160                         !core_useragent::is_webkit_android('533.1')) {
1161                     continue;
1162                 }
1163
1164                 $result[] = $url;
1165             }
1166         }
1167         return $result;
1168     }
1169
1170     public function get_rank() {
1171         return 10;
1172     }
1173 }
1174
1175
1176 /**
1177  * Special media player class that just puts a link.
1178  *
1179  * Always enabled, used as the last fallback.
1180  *
1181  * @copyright 2011 The Open University
1182  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1183  */
1184 class core_media_player_link extends core_media_player {
1185     public function embed($urls, $name, $width, $height, $options) {
1186         // If link is turned off, return empty.
1187         if (!empty($options[core_media::OPTION_NO_LINK])) {
1188             return '';
1189         }
1190
1191         // Build up link content.
1192         $output = '';
1193         foreach ($urls as $url) {
1194             $title = core_media::get_filename($url);
1195             $printlink = html_writer::link($url, $title, array('class' => 'mediafallbacklink'));
1196             if ($output) {
1197                 // Where there are multiple available formats, there are fallback links
1198                 // for all formats, separated by /.
1199                 $output .= ' / ';
1200             }
1201             $output .= $printlink;
1202         }
1203         return $output;
1204     }
1205
1206     public function list_supported_urls(array $urls, array $options = array()) {
1207         // Supports all URLs.
1208         return $urls;
1209     }
1210
1211     public function is_enabled() {
1212         // Cannot be disabled.
1213         return true;
1214     }
1215
1216     public function get_rank() {
1217         return 0;
1218     }
1219 }