Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Base class for media players

 *

 * @package   core_media

 * @copyright 2016 Marina Glancy

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

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

/**

 * Base class for media players.

 *

 * Media players return embed HTML for a particular way of playing back audio

 * or video (or another file type).

 *

 * @package   core_media

 * @copyright 2016 Marina Glancy

 * @author    2011 The Open University

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

abstract class core_media_player {

    /**

     * Placeholder text used to indicate where the fallback content is placed

     * within a result.

     */

    const PLACEHOLDER = '<!--FALLBACK-->';

    /**

     * Placeholder text used to indicate where the link fallback is placed.

     * No other players will apply to it but it will be converted to the link in the

     * end (unless prevented by OPTION_NO_LINK).

     */

    const LINKPLACEHOLDER = '<!--LINKFALLBACK-->';

    /**

     * Generates code required to embed the player.

     *

     * The returned code contains a placeholder comment '<!--FALLBACK-->'

     * (constant core_media_player::PLACEHOLDER) which indicates the location

     * where fallback content should be placed in the event that this type of

     * player is not supported by user browser.

     *

     * The $urls parameter includes one or more alternative media formats that

     * are supported by this player. It does not include formats that aren't

     * supported (see list_supported_urls).

     *

     * The $options array contains key-value pairs. See OPTION_xx constants

     * for documentation of standard option(s).

     *

     * @param array $urls URLs of media files

     * @param string $name Display name; '' to use default

     * @param int $width Optional width; 0 to use default

     * @param int $height Optional height; 0 to use default

     * @param array $options Options array

     * @return string HTML code for embed

     */

    abstract public function embed($urls, $name, $width, $height, $options);

    /**

     * Gets the list of file extensions supported by this media player.

     *

     * Note: This is only required for the default implementations of

     * list_supported_urls(), get_embeddable_markers() and supports().

     * If you override these functions to determine

     * supported URLs in some way other than by extension, then this function

     * is not necessary.

     *

     * @return array Array of strings (extension not including dot e.g. '.mp3')

     */

    public function get_supported_extensions() {

        return array();

    }

    /**

     * Lists keywords that must be included in a url that can be embedded with

     * this player. Any such keywords should be added to the array.

     *

     * For example if this player supports FLV and F4V files then it should add

     * '.flv' and '.f4v' to the array. (The check is not case-sensitive.)

     *

     * Default handling calls the get_supported_extensions function, so players

     * only need to override this if they don't implement get_supported_extensions.

     *

     * This is used to improve performance when matching links in the media filter.

     *

     * @return array Array of keywords to add to the embeddable markers list

     */

    public function get_embeddable_markers() {

        return $this->get_supported_extensions();

    }

    /**

     * Returns human-readable string of supported file/link types for the "Manage media players" page

     * @param array $usedextensions extensions that should NOT be highlighted

     * @return string

     */

    public function supports($usedextensions = []) {

        $out = [];

        if ($extensions = $this->get_supported_extensions()) {

            $video = $audio = $other = [];

            foreach ($extensions as $key => $extension) {

                $displayextension = $extension;

                if (!in_array($extension, $usedextensions)) {

                    $displayextension = '<strong>'.$extension.'</strong>';

                }

                if (file_extension_in_typegroup('file.'.$extension, 'audio')) {

                    $audio[] = $displayextension;

                } else if (file_extension_in_typegroup('file.'.$extension, 'video')) {

                    $video[] = $displayextension;

                } else {

                    $other[] = $displayextension;

                }

            }

            if ($video) {

                $out[] = get_string('videoextensions', 'core_media', join(', ', $video));

            }

            if ($audio) {

                $out[] = get_string('audioextensions', 'core_media', join(', ', $audio));

            }

            if ($other) {

                $out[] = get_string('extensions', 'core_media', join(', ', $other));

            }

        }

        return join('<br>', $out);

    }

    /**

     * Gets the ranking of this player. This is an integer used to decide which

     * player to use (after applying other considerations such as which ones

     * the user has disabled).

     *

     * This function returns the default rank that can be adjusted by the administrator

     * on the Manage media players page.

     *

     * @return int Rank (higher is better)

     */

    abstract public function get_rank();

    /**

     * @deprecated since Moodle 3.2

     */

    public function is_enabled() {

        throw new coding_exception('core_media_player::is_enabled() can not be used anymore.');

    }

    /**

     * Given a list of URLs, returns a reduced array containing only those URLs

     * which are supported by this player. (Empty if none.)

     * @param array $urls Array of moodle_url

     * @param array $options Options (same as will be passed to embed)

     * @return array Array of supported moodle_url

     */

    public function list_supported_urls(array $urls, array $options = array()) {

        $extensions = $this->get_supported_extensions();

        $result = array();

        foreach ($urls as $url) {

            $ext = core_media_manager::instance()->get_extension($url);

            if (in_array('.' . $ext, $extensions) || in_array($ext, $extensions)) {

                $result[] = $url;

            }

        }

        return $result;

    }

    /**

     * Obtains suitable name for media. Uses specified name if there is one,

     * otherwise makes one up.

     * @param string $name User-specified name ('' if none)

     * @param array $urls Array of moodle_url used to make up name

     * @return string Name

     */

    protected function get_name($name, $urls) {

        // If there is a specified name, use that.

        if ($name) {

            return $name;

        }

        // Get filename of first URL.

        $url = reset($urls);

        $name = core_media_manager::instance()->get_filename($url);

        // If there is more than one url, strip the extension as we could be

        // referring to a different one or several at once.

        if (count($urls) > 1) {

            $name = preg_replace('~\.[^.]*$~', '', $name);

        }

        return $name;

    }

    /**

     * @deprecated since Moodle 3.2

     */

    public static function compare_by_rank() {

        throw new coding_exception('core_media_player::compare_by_rank() can not be used anymore.');

    }

    /**

     * Utility function that sets width and height to defaults if not specified

     * as a parameter to the function (will be specified either if, (a) the calling

     * code passed it, or (b) the URL included it).

     * @param int $width Width passed to function (updated with final value)

     * @param int $height Height passed to function (updated with final value)

     */

    protected static function pick_video_size(&$width, &$height) {

        global $CFG;

        if (!$width) {

            $width = $CFG->media_default_width;

            $height = $CFG->media_default_height;

        }

    }

    /**

     * Setup page requirements.

     *

     * The typical javascript requirements MUST not take action on the content

     * directly. They are meant to load the required libraries and listen

     * to events in order to know when to take action. The role of this method

     * is not to provide a way for plugins to look for content to embed on the

     * page. The {@link self::embed()} method is meant to be used for that.

     *

     * @param moodle_page $page The page we are going to add requirements to.

     * @since Moodle 3.2

     */

    public function setup($page) {

        // Override is need be.

    }

}