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/>.

namespace mod_h5pactivity\xapi;

use mod_h5pactivity\local\attempt;

use mod_h5pactivity\local\manager;

use mod_h5pactivity\event\statement_received;

use core_xapi\local\statement;

use core_xapi\handler as handler_base;

use core\event\base as event_base;

use core_xapi\local\state;

use moodle_exception;

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

global $CFG;

require_once($CFG->dirroot.'/mod/h5pactivity/lib.php');

/**

 * Class xapi_handler for H5P statements and states.

 *

 * @package    mod_h5pactivity

 * @since      Moodle 3.9

 * @copyright  2020 Ferran Recio <ferran@moodle.com>

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

 */

class handler extends handler_base {

    /**

     * Convert a statement object into a Moodle xAPI Event.

     *

     * If a statement is accepted by the xAPI webservice the component must provide

     * an event to handle that statement, otherwise the statement will be rejected.

     *

     * @param statement $statement

     * @return core\event\base|null a Moodle event to trigger

     */

    public function statement_to_event(statement $statement): ?event_base {

        // Only process statements with results.

        $xapiresult = $statement->get_result();

        if (empty($xapiresult)) {

            return null;

        }

        // Statements can contain any verb, for security reasons each

        // plugin needs to filter it's own specific verbs. For now the only verbs the H5P

        // plugin keeps track on are "answered" and "completed" because they are realted to grading.

        // In the future this list can be increased to track more user interactions.

        $validvalues = [

                'http://adlnet.gov/expapi/verbs/answered',

                'http://adlnet.gov/expapi/verbs/completed',

            ];

        $xapiverbid = $statement->get_verb_id();

        if (!in_array($xapiverbid, $validvalues)) {

            return null;

        }

        // Validate object.

        $xapiobject = $statement->get_activity_id();

        // H5P add some extra params to ID to define subcontents.

        $parts = explode('?', $xapiobject, 2);

        $contextid = array_shift($parts);

        $subcontent = str_replace('subContentId=', '', array_shift($parts) ?? '');

        if (empty($contextid) || !is_numeric($contextid)) {

            return null;

        }

        $context = \context::instance_by_id($contextid);

        if (!$context instanceof \context_module) {

            return null;

        }

        // As the activity does not accept group statement, the code can assume that the

        // statement user is valid (otherwise the xAPI library will reject the statement).

        $user = $statement->get_user();

        if (!has_capability('mod/h5pactivity:view', $context, $user)) {

            return null;

        }

        $cm = get_coursemodule_from_id('h5pactivity', $context->instanceid, 0, false);

        if (!$cm) {

            return null;

        }

        $manager = manager::create_from_coursemodule($cm);

        if (!($manager->is_tracking_enabled() && $manager->can_submit($user))) {

            return null;

        }

        // For now, attempts are only processed on a single batch starting with the final "completed"

        // and "answered" statements (this could change in the future). This initial statement have no

        // subcontent defined as they are the main finishing statement. For this reason, this statement

        // indicates a new attempt creation. This way, simpler H5P activies like multichoice can generate

        // an attempt each time the user answers while complex like question-set could group all questions

        // in a single attempt (using subcontents).

        if (empty($subcontent)) {

            $attempt = attempt::new_attempt($user, $cm);

        } else {

            $attempt = attempt::last_attempt($user, $cm);

        }

        if (!$attempt) {

            return null;

        }

        $result = $attempt->save_statement($statement, $subcontent);

        if (!$result) {

            return null;

        }

        // Update activity if necessary.

        if ($attempt->get_scoreupdated()) {

            $grader = $manager->get_grader();

            $grader->update_grades($user->id);

        }

        // Convert into a Moodle event.

        $minstatement = $statement->minify();

        $params = [

            'other' => $minstatement,

            'context' => $context,

            'objectid' => $cm->instance,

            'userid' => $user->id,

        ];

        return statement_received::create($params);

    }

    /**

     * Validate a xAPI state.

     *

     * Check if the state is valid for this handler.

     *

     * This method is used also for the state get requests so the validation

     * cannot rely on having state data.

     *

     * @param state $state

     * @return bool if the state is valid or not

     */

    protected function validate_state(state $state): bool {

        $xapiobject = $state->get_activity_id();

        // H5P add some extra params to ID to define subcontents.

        $parts = explode('?', $xapiobject, 2);

        $contextid = array_shift($parts);

        if (empty($contextid) || !is_numeric($contextid)) {

            return false;

        }

        try {

            $context = \context::instance_by_id($contextid);

            if (!$context instanceof \context_module) {

                return false;

            }

        } catch (moodle_exception $exception) {

            return false;

        }

        $cm = get_coursemodule_from_id('h5pactivity', $context->instanceid, 0, false);

        if (!$cm) {

            return false;

        }

        // If tracking is not enabled or the user can't submit, the state won't be considered valid.

        $manager = manager::create_from_coursemodule($cm);

        $user = $state->get_user();

        if (!($manager->is_tracking_enabled() && $manager->can_submit($user))) {

            return false;

        }

        return true;

    }

}