Proyectos de Subversion Moodle

// 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/>.

/**

 * Poll the server to keep the session alive.

 *

 * @module     core/network

 * @copyright  2019 Damyon Wiese

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

 */

define(['jquery', 'core/ajax', 'core/config', 'core/notification', 'core/str'],

        function($, Ajax, Config, Notification, Str) {

    var started = false;

    var warningDisplayed = false;

    var keepAliveFrequency = 0;

    var requestTimeout = 0;

    var keepAliveMessage = false;

    var sessionTimeout = false;

    // 1/10 of session timeout, max of 10 minutes.

    var checkFrequency = Math.min((Config.sessiontimeout / 10), 600) * 1000;

    // Check if sessiontimeoutwarning is set or double the checkFrequency.

    var warningLimit = (Config.sessiontimeoutwarning > 0) ? (Config.sessiontimeoutwarning * 1000) : (checkFrequency * 2);

    // First wait is minimum of remaining time or half of the session timeout.

    var firstWait = (Config.sessiontimeoutwarning > 0) ?

        Math.min((Config.sessiontimeout - Config.sessiontimeoutwarning) * 1000, checkFrequency * 5) : checkFrequency * 5;

    /**

     * The session time has expired - we can't extend it now.

     * @param {Modal} modal

     */

    var timeoutSessionExpired = function(modal) {

        sessionTimeout = true;

        warningDisplayed = false;

        closeModal(modal);

        displaySessionExpired();

    };

    /**

     * Close modal - this relies on modal object passed from Notification.confirm.

     *

     * @param {Modal} modal

     */

    var closeModal = function(modal) {

        modal.destroy();

    };

    /**

     * The session time has expired - we can't extend it now.

     * @return {Promise}

     */

    var displaySessionExpired = function() {

        // Check again if its already extended before displaying session expired popup in case multiple tabs are open.

        var request = {

            methodname: 'core_session_time_remaining',

            args: { }

        };

        return Ajax.call([request], true, true, true)[0].then(function(args) {

            if (args.timeremaining * 1000 > warningLimit) {

                return false;

            } else {

                return Str.get_strings([

                    {key: 'sessionexpired', component: 'error'},

                    {key: 'sessionerroruser', component: 'error'},

                    {key: 'loginagain', component: 'moodle'},

                    {key: 'cancel', component: 'moodle'}

                ]).then(function(strings) {

                    Notification.confirm(

                        strings[0], // Title.

                        strings[1], // Message.

                        strings[2], // Login Again.

                        strings[3], // Cancel.

                        function() {

                            location.reload();

                            return true;

                        }

                    );

                    return true;

                }).catch(Notification.exception);

            }

        });

    };

    /**

     * Ping the server to keep the session alive.

     *

     * @return {Promise}

     */

    var touchSession = function() {

        var request = {

            methodname: 'core_session_touch',

            args: { }

        };

        if (sessionTimeout) {

            // We timed out before we extended the session.

            return displaySessionExpired();

        } else {

            return Ajax.call([request], true, true, false, requestTimeout)[0].then(function() {

                if (keepAliveFrequency > 0) {

                    setTimeout(touchSession, keepAliveFrequency);

                }

                return true;

            }).catch(function() {

                Notification.alert('', keepAliveMessage);

            });

        }

    };

    /**

     * Ask the server how much time is remaining in this session and

     * show confirm/cancel notifications if the session is about to run out.

     *

     * @return {Promise}

     */

    var checkSession = function() {

        var request = {

            methodname: 'core_session_time_remaining',

            args: { }

        };

        sessionTimeout = false;

        return Ajax.call([request], true, true, true)[0].then(function(args) {

            if (args.userid <= 0) {

                return false;

            }

            if (args.timeremaining <= 0) {

                return displaySessionExpired();

            } else if (args.timeremaining * 1000 <= warningLimit && !warningDisplayed) {

                warningDisplayed = true;

                Str.get_strings([

                    {key: 'norecentactivity', component: 'moodle'},

                    {key: 'sessiontimeoutsoon', component: 'moodle'},

                    {key: 'extendsession', component: 'moodle'},

                    {key: 'cancel', component: 'moodle'}

                ]).then(function(strings) {

                     return Notification.confirm(

                        strings[0], // Title.

                        strings[1], // Message.

                        strings[2], // Extend session.

                        strings[3], // Cancel.

                        function() {

                            touchSession();

                            warningDisplayed = false;

                            // First wait is minimum of remaining time or half of the session timeout.

                            setTimeout(checkSession, firstWait);

                            return true;

                        },

                        function() {

                            // User has cancelled notification.

                            setTimeout(checkSession, checkFrequency);

                        }

                    );

                }).then(modal => {

                    // If we don't extend the session before the timeout - warn.

                    setTimeout(timeoutSessionExpired, args.timeremaining * 1000, modal);

                    return;

                }).catch(Notification.exception);

            } else {

                setTimeout(checkSession, checkFrequency);

            }

            return true;

        });

        // We do not catch the fails from the above ajax call because they will fail when

        // we are not logged in - we don't need to take any action then.

    };

    /**

     * Start calling a function to check if the session is still alive.

     */

    var start = function() {

        if (keepAliveFrequency > 0) {

            setTimeout(touchSession, keepAliveFrequency);

        } else {

            // First wait is minimum of remaining time or half of the session timeout.

            setTimeout(checkSession, firstWait);

        }

    };

    /**

     * Are we in an iframe and the parent page is from the same Moodle site?

     *

     * @return {boolean} true if we are in an iframe in a page from this Moodle site.

     */

    const isMoodleIframe = function() {

        if (window.parent === window) {

            // Not in an iframe.

            return false;

        }

        // We are in an iframe. Is the parent from the same Moodle site?

        let parentUrl;

        try {

            parentUrl = window.parent.location.href;

        } catch (e) {

            // If we cannot access the URL of the parent page, it must be another site.

            return false;

        }

        return parentUrl.startsWith(M.cfg.wwwroot);

    };

    /**

     * Don't allow more than one of these polling loops in a single page.

     */

    var init = function() {

        // We only allow one concurrent instance of this checker.

        if (started) {

            return;

        }

        started = true;

        if (isMoodleIframe()) {

            window.console.log('Not starting Moodle session timeout warning in this iframe.');

            return;

        }

        window.console.log('Starting Moodle session timeout warning.');

        start();

    };

    /**

     * Start polling with more specific values for the frequency, timeout and message.

     *

     * @param {number} freq How ofter to poll the server.

     * @param {number} timeout The time to wait for each request to the server.

     * @param {string} identifier The string identifier for the message to show if session is going to time out.

     * @param {string} component The string component for the message to show if session is going to time out.

     */

    var keepalive = async function(freq, timeout, identifier, component) {

        // We only allow one concurrent instance of this checker.

        if (started) {

            window.console.warn('Ignoring session keep-alive. The core/network module was already initialised.');

            return;

        }

        started = true;

        if (isMoodleIframe()) {

            window.console.warn('Ignoring session keep-alive in this iframe inside another Moodle page.');

            return;

        }

        window.console.log('Starting Moodle session keep-alive.');

        keepAliveFrequency = freq * 1000;

        keepAliveMessage = await Str.get_string(identifier, component);

        requestTimeout = timeout * 1000;

        start();

    };

    return {

        keepalive: keepalive,

        init: init

    };

});