sync.php

<?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/>.

/**
 * This script processes ajax sync (saving) requests during the quiz.
 *
 * @package   quizaccess_wifiresilience
 * @copyright 2017 ETH Zurich (amr.hourani@let.ethz.ch)
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

define('AJAX_SCRIPT', true);

require_once(__DIR__ . '/../../../../config.php');
require_once($CFG->dirroot . '/mod/quiz/locallib.php');

// Remember the current time as the time any responses were submitted.
// (so as to make sure students don't get penalized for slow processing on this page).
$timenow = time();

// Get submitted parameters.
$attemptid = required_param('attempt',  PARAM_INT);
$thispage  = optional_param('thispage', 0, PARAM_INT);
$timeup  = optional_param('timeup', 0, PARAM_INT);
$finishattempt = optional_param('finishattempt', false, PARAM_BOOL);
$finalsubmissiontime = optional_param('final_submission_time', 0, PARAM_INT);
$cmid = optional_param('cmid', null, PARAM_INT);
$wifisaveattemptdata = optional_param('wifisaveattemptdata', 0, PARAM_INT);

$transaction = $DB->start_delegated_transaction();
//$attemptobj = quiz_attempt::create($attemptid);
$attemptobj = quiz_create_attempt_handling_errors($attemptid, $cmid);


// Check login.
if (!isloggedin() || !confirm_sesskey()) {
    echo json_encode(array('result' => 'lostsession'));
    die;
}
require_login($attemptobj->get_course(), false, $attemptobj->get_cm());
require_sesskey();

// Check that this attempt belongs to this user.
if ($attemptobj->get_userid() != $USER->id) {
    throw new moodle_exception('notyourattempt');
}

// Check capabilities.
if (!$attemptobj->is_preview_user()) {
    $attemptobj->require_capability('mod/quiz:attempt');
}

$options = $attemptobj->get_display_options(false);

// If the attempt is already closed, send them to the review page.
if ($attemptobj->is_finished()) {
  $result = array('result' => 'OK', 'reviewurl' => $attemptobj->review_url()->out(false));
  echo json_encode($result);
  exit;
}
/*** tobias */
// Check if its latest active session.
$ativesessobj = ['sesskey' => sesskey(), 'userid' => $USER->id, 'attemptid' => $attemptid];
$latestactivesession = $DB->get_record('quizaccess_wifiresilience_sess', $ativesessobj);
if(!$latestactivesession){
  $result = array('result' => 'blockattempt');
  echo json_encode($result);
  require_logout();
  die;
}
/*** end tobias */

// Fix potenial out of sequence issues.
foreach ($attemptobj->get_slots() as $slot) {
  $qa = $attemptobj->get_question_attempt($slot);
  $_POST[$qa->get_control_field_name('sequencecheck')] = (string)$qa->get_sequence_check_count();
  //unset($_POST[$qa->get_control_field_name('sequencecheck')]);
}

//exit;

$duedate = $attemptobj->get_due_date();

if ($finishattempt) {
    // Submit and finish. If tried to submit on time but delays happen etc.
    // Give them exceptional 30 mins in case of connection issues.
    if ($duedate && $timenow > $duedate && ($timenow - $duedate) <= 1800) {
        $timenow = $duedate;
    }
    $attemptobj->process_finish($timenow, true);
    $result = array('result' => 'OK', 'reviewurl' => $attemptobj->review_url()->out(false));

    // Delete latest active session.
    $ativesessobj = ['id' => $latestactivesession->id];
    $DB->delete_records('quizaccess_wifiresilience_sess', $ativesessobj);

} else {
    // Process the responses.
    if($wifisaveattemptdata == 1) {
        $attemptobj->process_attempt($timenow, $finishattempt, $timeup, $thispage);
    } else {
        $attemptobj->process_auto_save($timenow);
    }   

    // Update current page number.
    if ($thispage >= 0 && $attemptobj->get_currentpage() != $thispage) {
        $DB->set_field('quiz_attempts', 'currentpage', $thispage, array('id' => $attemptid));
    }

    // Get the question states, and put them in a response.
    $result = array('result' => 'OK', 'questionstates' => array(), 'questionstatestrs' => array(), 
                    'timerstartvalue' => array(), 'sequencecheck' => array(), 'questionflagged' => array());
    foreach ($attemptobj->get_slots() as $slot) {
        $result['questionstates'][$slot] = $attemptobj->get_question_state_class(
                $slot, $options->correctness);
        $result['questionstatestrs'][$slot] = $attemptobj->get_question_status(
                $slot, $options->correctness);
        $result['questionflagged'][$slot] = $attemptobj->is_question_flagged($slot);   
        // get sequencecheck history.
        $qa = $attemptobj->get_question_attempt($slot);
        $result['sequencecheck'][$slot] = $qa->get_sequence_check_count();       
    }

}

$transaction->allow_commit();


$endtime = $attemptobj->get_quizobj()->get_access_manager(time())->get_end_time($attemptobj->get_attempt());


if ($endtime === false) {
    $endtime = 0;
}

$timeleft = $attemptobj->get_time_left_display(time());

if ($timeleft !== false) {
    $ispreview = $attemptobj->is_preview();
    $timerstartvalue = $timeleft;
    if (!$ispreview) {
        /*
        Make sure the timer starts just above zero. If $timeleft was <= 0, then
        this will just have the effect of causing the quiz to be submitted immediately.
        */
        $timerstartvalue = max($timerstartvalue, 1);
    }
} else {
    $timerstartvalue = 0;
}
$result['timerstartvalue'] = $timerstartvalue;
$result['timelimit'] = $endtime;
echo json_encode($result);