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// 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/>.function NewHttpReq() {var httpReq = false;if (typeof XMLHttpRequest != 'undefined') {httpReq = new XMLHttpRequest();} else {try {httpReq = new ActiveXObject("Msxml2.XMLHTTP.4.0");} catch (e) {try {httpReq = new ActiveXObject("Msxml2.XMLHTTP");} catch (ee) {try {httpReq = new ActiveXObject("Microsoft.XMLHTTP");} catch (eee) {httpReq = false;}}}}return httpReq;}/**** @param {XMLHttpRequest} httpReq* @param {string} url* @param {string} param* @param {boolean} allowBeaconAPI Should the BeaconAPI be used if required? Defaults to true* If True, and we can use the Beacon API and are should use the beacon API then we will.* If False, we will not use the Beacon API, even if we expect a synchronous XHR request to fail.* @returns {string|boolean|*}* @constructor*/function DoRequest(httpReq, url, param, allowBeaconAPI) {// Default allowBeaconAPI to true. This argument was added to the function late.if (typeof allowBeaconAPI === 'undefined') {allowBeaconAPI = true;}/*** Returns true if we are able to use the Beacon API in this browser.* @returns boolean*/var canUseBeaconAPI = function() {return (allowBeaconAPI && navigator && navigator.sendBeacon && FormData);};/*** Returns true if we should use the Beacon API.* We don't use the Beacon API unless we have to as it stiffles our ability to return data on the request.* @returns {boolean}*/var useBeaconAPI = function() {if (typeof window.mod_scorm_useBeaconAPI === 'undefined' || window.mod_scorm_useBeaconAPI === false) {// Last ditch effort, the SCORM package may have introduced its own listeners before our listeners.// This is OLD API, window.event is not reliable and is not recommended API.// https://developer.mozilla.org/en-US/docs/Web/API/Window/eventif (window.event && ['beforeunload', 'unload', 'pagehide'].indexOf(window.event.type)) {window.mod_scorm_useBeaconAPI = true;}}return (window.mod_scorm_useBeaconAPI && canUseBeaconAPI());};/*** Uses the Beacon API to communicate this request to the server.* This function always returns a successful result, because we don't get the actual result, the page doesn't wait for it.* @param {string} url* @param {string} param* @returns {string}*/var useSendBeacon = function(url, param) {// Ok, old API alert, the param is a URI encoded string. We need to split it and convert it to a supported format.// I've chosen FormData and FormData.append as they are compatible with our supported browsers:// - https://developer.mozilla.org/en-US/docs/Web/API/FormData/FormData// - https://developer.mozilla.org/en-US/docs/Web/API/FormData/appendvar vars = param.split('&'),i = 0,pair,key,value,formData = new FormData();for (i = 0; i < vars.length; i++) {pair = vars[i].split('=');key = decodeURIComponent(pair[0]);value = decodeURIComponent(pair[1]);formData.append(key, value);}// We'll also inform it that we are unloading, potentially useful in the future.formData.append('unloading', '1');// We're going to add a token to the URL that will identify this request as going to the beacon API.// In the future this would allow our server side scripts to respond differently when the beacon API// is being used, as the response will be discarded.if (url.indexOf('?') === -1) {// First paramurl += '?api=beacon';} else {url += '&api=beacon';}// The results is true or false, we don't get the response from the server. Make it look like it was a success.var outcome = navigator.sendBeacon(url, formData);if (!outcome) {if (console && console.log) {console.log('mod_scorm: Failed to queue navigator.sendBeacon request');}return "false\n101";}// This is what a success looks like when it comes back from the server.return "true\n0";};// If we are unloading, and we can use sendBeacon then do that, Chrome does not permit synchronous XHR requests on unload.if (useBeaconAPI()) {return useSendBeacon(url, param);}// httpReq.open (Method("get","post"), URL(string), Asyncronous(true,false))//popupwin(url+"\n"+param);httpReq.open("POST", url,false);httpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');try {httpReq.send(param);} catch (e) {if (console && console.log) {// This may be frivolous as during a shutdown the console log will most likely be lost. But it may help someone.var message = 'XHR request from mod_scorm::DoRequest failed';if (canUseBeaconAPI()) {message += '; attempting to use Beacon API.';}console.log(message);}// The HTTP request failed. We don't know why, but as a last ditch effort, in case we are unloading and haven't detected it// we will attempt to send the request one more time using the Beacon API. This will result in a successful result regardless// of the actual outcome.if (canUseBeaconAPI()) {return useSendBeacon(url, param);}return false;}if (httpReq.status == 200) {//popupwin(url+"\n"+param+"\n"+httpReq.responseText);return httpReq.responseText;} else {return httpReq.status;}}function popupwin(content) {var op = window.open();op.document.open('text/plain');op.document.write(content);op.document.close();}/*** Global variable to track whether we should use the Beacon API instead of synchronous XHR.* This gets set to true in situations where we expect synchronoush XHR requests to fail.*/window.mod_scorm_useBeaconAPI = false;/*** We wire up a small marker for the unload events triggered when the user is navigating away or closing the tab.* This is done because Chrome does not allow synchronous XHR requests on the following unload events:* - beforeunload* - unload* - pagehide* - visibilitychange*/function mod_scorm_monitorForBeaconRequirement(target) {if (typeof target.mod_scorm_monitoring_for_beacon_requirement !== 'undefined') {// We're already observing unload events on this target.console.log('mod_scorm: unload event handlers already attached');return;}target.mod_scorm_monitoring_for_beacon_requirement = true;// The navigator.sendBeacon API is available in all browsers EXCEPT Internet Explorer (IE)// Internet explorer should never get past this check.if (!navigator || !navigator.sendBeacon) {// We can't use the BeaconAPI. There is no point in proceeding to observe unload events.// This is done after adding the flag to target, and establishing the window variable.return;}/*** Turns on the use of the Beacon API.*/var toggleOn = function() {window.mod_scorm_useBeaconAPI = true;};/*** Turns off the use of the Beacon API.*/var toggleOff = function() {window.mod_scorm_useBeaconAPI = false;};/*** Observes an event.* Required because this patch will be backported.* @param {string} on* @param {CallableFunction} callback*/var observe = function(on, callback) {if (!target.addEventListener) {console.log('Unable to attach page dismissal event listeners');return null;}return target.addEventListener(on, callback);};// Listen to the three events known to represent an unload operation.observe('beforeunload', toggleOn);observe('unload', toggleOn);observe('pagehide', toggleOn);// Listen to the event fired when navigating to a page and ensure we toggle useBeaconAPI off.// This shouldn't be needed (page should be uncached) but just in case!observe('pageshow', toggleOff);// Finally listen to the visibility change event, and respond to it.// This unfortunately is not ideal, but is required as a SCORM package may also be listening to this and// trying to save content when the user hides the page. As this can occur as part of the page dismissal lifecycle// we also need to ensure we use the Beacon API here.observe('visibilitychange', function() {// Visible means synchronous XHR permitted, use XHR.// Hidden means synchronous XHR not permitted, use Beacon API.if (document.visibilityState === 'visible' || document.visibilityState === 'prerender') {toggleOff();} else if (document.visibilityState === 'hidden') {toggleOn();}});}// Begin monitoring on the main window immediately.mod_scorm_monitorForBeaconRequirement(window);