I have the following piece of code from my webpage that checks for Internet connectivity.
When Internet is available, it should reload the page after 10 seconds. Otherwise, it waits indefinitely for connectivity.
function checkJSNetConnection(){
var xhr = new XMLHttpRequest();
var file = "https://dl.dropboxusercontent.com/s/9d7ri25ku7xlj9u/WALL-E%20%281%29.jpg?dl=0";
var r = Math.round(Math.random() * 10000);
xhr.open('HEAD', file + "?subins=" + r, false);
try {
xhr.send();
if (xhr.status >= 200 && xhr.status < 304) {
return true;
} else {
return false;
}
} catch (e) {
return false;
}
}
function timedRefresh(timeoutPeriod) {
if(checkJSNetConnection()==false){
alert("Internet Connection does not Exist");
} else {
setTimeout("location.reload(true);",timeoutPeriod);
}
}
The function is called from:
<body onload="JavaScript:timedRefresh(10000);">
The problem is that, although it successfully reloads the page when Internet is available, it doesn't show an alert message for no connectivity, showing instead "unable to load page".
Think about it, if there is an internet connection, it sets the page to reload after 10 seconds right?
so, lets assume it passed the internet connectivity test, and 10 seconds countdown started. now suddenly connection is lost, the countdown reaches zero and refreshes the page (tries to get a new copy of it from the website) but since there is no internet connectivity, it just fails and says that the page is not available.
a possible solution: (there are more, this is one)
dont set a time out, if internet is available, reload right away and start a new timeout on the connectivity check:
change "timed refresh" to "timed check" logic:
<body onload="JavaScript:setTimeout(timedCheck,10000);">
and the script:
function timedCheck(timeoutPeriod) {
if(checkJSNetConnection()==false){
alert("Internet Connection doesnot Exist");
}else{
location.reload(true);
}
}
this way, when the page first loads, it will start a countdown of 10 seconds at the end of which a test will be made. if there is a connection available, it will reload immediately and a new countdown will start. if there is no connection, it will show the alert.
I have a script that uses PHP SESSION. I manage PHP sessions using a class. Within this class I have a method that returns how many seconds remaining before the session expires.
Also, Evey time the user refresh the page or open a new page (new request to the server) the idle time counter starts over $_SESSION['MA_IDLE_TIMEOUT'] = time()+900;
What I am looking to do is display a dialog message 2 minutes before the PHP session expire and check if the user is still on the page or not. If the use clicks "Keep working" then the jQuery script will send PHP AJAX request to renew the session $_SESSION['MA_IDLE_TIMEOUT'] = time()+900;. If the user did not click anything or clicked on "Log out" then the session ends and the user is redirected to the login page.
I did find a nice plugin that will somewhat does the Job jquery-idle-timeout
The issue with this plugin is that it checks if the user is idle using JavaScript (if the keyboard/mouse) are being used. Here is the senario where this script does not help me: lets say my PHP sessions has a limit on 15 minutes/ 900 seconds. A user is reading a super long article on the same page. He/she will be scrolling, they are not really idle "from JavaScript perspective" but from a PHP perspective the use is idle. Then after 20 minutes the user refresh the page, then the user will be logged out since he/she have not sent a new request to the PHP server for over the 900 seconds limit.
How can I solve this problem? is there a better plugin to does the trick? if there something I missed in this plugin that will solve my problem?
Thanks
If the user is not making requests, and is not moving the mouse or keyboard or touching the device, etc., then from the app's point of view the user is "idle" even if their eyeballs are not.
If the user is scrolling you can use javascript to listen for scroll events (via onscroll, for example), but this will not be 100% reliable because (1) depends on javascript, and (2) doesn't work if you are viewing a short article or using a tall/large format monitor (like the ones you can rotate 90 degrees, for example).
Perhaps you could handle this differently: use cookies, single sign-on or similar techniques to pre-authenticate or automatically authenticate requests so that the user's session can safely die and be restarted without the user having to manually login.
The other way you could handle this is to maintain a "ping" process that routinely pings the server (via setInterval(), for example) to keep the session alive, and uses a separate timeout (maybe something like the "Authentication timeout" that ASP.NET uses) to keep track of when the "idle" user should be logged out. Then user actions such as scrolling, requesting pages, focusing in fields, moving mouse, etc., can do a "ping reset" that resets the idle counter to 0.
Example / Concept - leaving as exercise for reader to perfect it:
var idleTime = 0; // how long user is idle
var idleTimeout = 1000 * 60 * 20; // logout if user is idle for 20 mins
var pingFrequency = 1000 * 60; // ping every 60 seconds
var warningTime = 1000 * 60 * 2; // warning at 2 mins left
var warningVisible = false; // whether user has been warned
setInterval(SendPing, pingFrequency);
setInterval(IdleCounter, 1000); // fire every second
function IdleCounter() {
idleTime += 1000; // update idleTime (possible logic flaws here; untested example)
if (console) console.log("Idle time incremented. Now = " + idleTime.toString());
}
function SendPing() {
if (idleTime < idleTimeout) {
// keep pinging
var pingUrl = "tools/keepSessionAlive.php?idleTime=" + idleTime;
$.ajax({
url: pingUrl,
success: function () {
if (console) console.log("Ping response received");
},
error: function () {
if (console) console.log("Ping response error");
}
});
// if 2 mins left, could show a warning with "Keep me on" button
if ((idleTime <= (idleTimeout - (idleTimeout - warningTime))) && !warningVisible) {
ShowTimeoutWarning();
}
} else {
// user idle too long, kick 'em out!
if (console) console.log("Idle timeout reached, logging user out..");
alert("You will be logged off now dude");
window.location.href = "logoff.aspx"; // redirect to "bye" page that kills session
}
}
function ShowTimeoutWarning() {
// use jQuery UI dialog or something fun for the warning
// when user clicks OK set warningVisible = false, and idleTime = 0
if (console) console.log("User was warned of impending logoff");
}
function ResetIdleTime() {
// user did something; reset idle counter
idleTime = 0;
if (console) console.log("Idle time reset to 0");
}
$(document) // various events that can reset idle time
.on("mousemove", ResetIdleTime)
.on("click", ResetIdleTime)
.on("keydown", ResetIdleTime)
.children("body")
.on("scroll", ResetIdleTime);
I use a time cookie to log out an inactive user like this:
`$time = time();
// 5 minutes since last request
if(!empty($_COOKIE['_time'] && $time - $_COOKIE['_time'] >= 300)
{
// log user out
}
setcookie('_time', $time, '/');`
Hope this helps.
Here is my code:
setTimeout(expireAndRedirect(), 200000)
It should call the function expireAndRedirect after 200 seconds.
It works only if it's on the same page on which the above function has been written. But I want it to work on application label.
Is there any way in JavaScript to run a thread after 200 seconds irrespective of on which page you are?
Use html5 local storage to save state between pages and check it on every page load. For example:
Setup:
localStorage.expireAndRedirectAfter = Date.now() + 200000;
setTimeout(function() {
expireAndRedirect();
localStorage.expireAndRedirectAfter = null;
}, 200000);
Check state on each page loading:
if (localStorage.expireAndRedirectAfter) {
if (localStorage.expireAndRedirectAfter > Date.now()) {
expireAndRedirect();
} else {
setTimeout(function() {
expireAndRedirect();
localStorage.expireAndRedirectAfter = null;
}, localStorage.expireAndRedirectAfter - Date.now());
}
}
This solution will work only if all your pages on same domain.
during login set a cookie with current datetime..
next in javascript on every page load check the difference in time and set the expiration accordingly..
I have used a javascript function to ping server again and again.
function server_ping(url, time_limit){
if(time_limit == undefined) time_limit = 3000;
$.get(url);
setTimeout(function(){server_ping(url);}, time_limit);
}
Although I have applied some work around, but this solution looks more like a hack.
var ping_timeout;
// clearing ping time out
if (ping_timeout != undefined){
clearTimeout(ping_timeout);
}
function server_ping(url, time_limit){
if(time_limit == undefined) time_limit = 3000;
$.get(url);
ping_timeout = setTimeout(function(){server_ping(url);}, time_limit);
}
Also I have pagination on my page, so when I am clicking next page, there are two requests now in the interval of 3 seconds. Also in my network console of chrome I noticed that page is not loading fully.
Is there some problem in browser, or I am missing something.
Also I have coded my application in rails and using gem will paginate for pagination.
Thanks
In my chat application i am having the logout button and it works fine.
Now I need to logout the application when I closed the browser window also..How can I achieve this...
Thanks in advance...
There is no exact way to do this with the clientside. There is no event that is fired when the page is exited. It should be done with the Session End event on the server.
You can try to use onbeforeunload or unload, but race conditions will prevent that from happening. AND they do not fire for browsers crashing, lost internet connection, etc.
I dealt with this issue recently in my angularJS app - The main issue was that I don't want to log you out if you refresh, but I do want to if you close the tab.. Ajax requests with onbeforeunload/onunload aren't guaranteed to wait for response, so here is my solution:
I set a sessionStorage cookie on login that is just a bool - set to true when I get login response
sessionStorage.setItem('activeSession', 'true');
Obviously, on logout, we set this flag to false
Either when controller initializes or using window.onload (in my app.js file) - I check for this activeSession bool.. if it is false, I have this small if statement - where if conditions are met I call my logout method ONLOAD instead of onunload
var activeSession = sessionStorage.activeSession;
if (sessionStorage.loggedOutOnAuth) {
console.log('Logged out due to expiry already')
}
else if (!activeSession) {
sessionStorage.loggedOutOnAuth = true;
_logout()
}
Basically, the "loggedOutAuth" bool let's me know that I just expired you on page load due to the absence of an activeSession in sessionStorage so you don't get stuck in a loop
This was a great solution for me since I didn't want to implement a heartbeat/websocket
Add your logout code to the on onunload event.
window.onunload = function () {
//logout code here...
}
In JQuery you can use the .unload() function. Remember that you don't have much time so you may send the Ajax request but the result may not reach the client.
Another trick is to open a small new window and handle the logout there.
window.open("logout url","log out","height=10,width=10,location=no,menubar=no,status=no,titlebar=no,toolbar=no",true);
If you want to disable closing the window (or at least warn the user), you can use this code:
window.onbeforeunload = function(event) {
//if you return anything but null, it will warn the user.
//optionally you can return a string which most browsers show to the user as the warning message.
return true;
}
Another trick is to keep pinging the client every few seconds. If no reply comes back, assume the user has closed the window, browser has crashed or there is a network issue that ended the chat session anyway. On the client side, if you don't receive this ping package, you can assume that network connection or server has a problem and you can show the logout warning (and optionally let the user login again).
Some websites are using the following script to detect whether window is closed or not.
if(window.screenTop > 10000)
alert("Window is closed");
else
alert("Window stillOpen");
You need to add the correct action instead of alert()
also take a look HERE - I think this is somthing you need to detect the window closing
I got the Solution by,
window.onunload = function () {
//logout code here...
}
Thanks for all who supported me...
Another approach is some sort of "keepalive": the browser page "pings" the server with a small ajax request every minute or so. If the server doesn't get the regular pings, the session is closed and can no longer be used.
As an optimization, the pings can be skipped if we have made another request to the server in the interim.
Advantages:
still works with multiple windows open
no problem with F5 / refresh
can provides some usage statistics to the server
Disadvantages:
when the window is closed, there is a delay before the user is logged out
uses a little network bandwidth
additional load on the server
users might have concerns about the page constantly "phoning home"
more difficult to implement
I've never actually done this in a web app, and not sure if I would; just putting it out there as an alternative. It seems like a good option for a chat app, where the server does need to know if you are still there.
Rather than polling / pinging, another possibility is to keep a "long running request" open while the page is open. A chat app needs some such socket to receive new messages and notifications. If the page is closed, the socket is closed too, and the server can notice that it has been closed. It then waits a brief time for the client to establish a new socket, and if it doesn't we assume the page is closed and delete the session. This would require some slightly unusual software on the server.
I was with this problem here and I come with a different solution:
checkSessionTime();
$interval(checkSessionTime, 2000);
function checkSessionTime() {
var now = (new Date()).getTime();
if (!$localStorage.lastPing) {
$localStorage.lastPing = now;
}
if ($localStorage.lastPing < now - 5000) {
$localStorage.lastPing = undefined;
AuthService.logout();
} else {
$localStorage.lastPing = now;
}
}
I like this solution cause it doesnt add overhead pinging the server nor rely on the window unload event. This code was put inside the $app.run.
I am using angular with a JWT auth, this way to me to log out just mean to get rid of the auth token. However, if you need to finish up the session server-side you can just build the Auth service to do one ping when finishing the session instead of keep pinging to maitain session alive.
This solutionsolves my case cause my intetion is just to prevent unwanted users to access someones account when they closed the tab and went away from the PC.
After lots of search I wrote the below customized code in javascript and server side code for session kill in c#.
The below code is extended in case of same website is open in multiple tabs so the session is alive till one tab of website is open
//Define global varible
var isCloseWindow = false;
//Jquery page load function to register the events
$(function () {
//function for onbeforeuload
window.onbeforeunload = ConfirmLeave;
//function for onload
window.onload = ConfirmEnter;
//mouseover for div which spans the whole browser client area
$("div").on('mouseover', (function () {
//for postback from the page make isCloseWindow global varible to false
isCloseWindow = false;
}));
//mouseout event
$("div").on('mouseout', (function () {
//for event raised from tabclose,browserclose etc. the page make isCloseWindow global varible to false
isCloseWindow = true;
}));
});
//Key board events to track the browser tab or browser closed by ctrl+w or alt+f4 key combination
$(document).keydown(function (e) {
if (e.key.toUpperCase() == "CONTROL") {
debugger;
isCloseWindow = true;
}
else if (e.key.toUpperCase() == "ALT") {
debugger;
isCloseWindow = true;
}
else {
debugger;
isCloseWindow = false;
}
});
function ConfirmEnter(event) {
if (localStorage.getItem("IsPostBack") == null || localStorage.getItem("IsPostBack") == "N") {
if (localStorage.getItem("tabCounter") == null || Number(localStorage.getItem("tabCounter")) == 0) {
//cookie is not present
localStorage.setItem('tabCounter', 1);
} else {
localStorage.setItem('tabCounter', Number(localStorage.getItem('tabCounter')) + 1);
}
}
localStorage.setItem("IsPostBack", "N");
}
function ConfirmLeave(event) {
if (event.target.activeElement.innerText == "LOGOUT") {
localStorage.setItem('tabCounter', 0);
localStorage.setItem("IsPostBack", "N");
} else {
localStorage.setItem("IsPostBack", "Y");
}
if ((Number(localStorage.getItem('tabCounter')) == 1 && isCloseWindow == true)) {
localStorage.setItem('tabCounter', 0);
localStorage.setItem("IsPostBack", "N");
**Call Web Method Kill_Session using jquery ajax call**
} else if (Number(localStorage.getItem('tabCounter')) > 1 && isCloseWindow == true) {
localStorage.setItem('tabCounter', Number(localStorage.getItem('tabCounter')) - 1);
}
}
//C# server side WebMethod
[WebMethod]
public static void Kill_Session()
{
HttpContext.Current.Session.Abandon();
}
For this issue I tried 2 solutions: window.onbeforeunload event and sessionStorage
Since window.onbeforeunload is not only for closing the browser but also redirect, tab refresh, new tab, it was not a robust solution. Also there are cases which the event does not happen: closing the browser through the command line, shutting down the computer
I switched to using sessionStorage. When the user logs in I set a sessionStorage variable to 'true'; when the application is loaded I would check to see if this variable is there, otherwise I would force the user to log in. However I need to share the sessionStorage variable across tabs so that a user is not forced to log in when they open a new tab in the same browser instance, I was able to do this by leveraging the storage event; a great example of this can be found here
tabOrBrowserStillAliveInterval;
constructor() {
// system should logout if the browser or last opened tab was closed (in 15sec after closing)
if (this.wasBrowserOrTabClosedAfterSignin()) {
this.logOut();
}
// every 15sec update browserOrTabActiveTimestamp property with new timestamp
this.setBrowserOrTabActiveTimestamp(new Date());
this.tabOrBrowserStillAliveInterval = setInterval(() => {
this.setBrowserOrTabActiveTimestamp(new Date());
}, 15000);
}
signin() {
// ...
this.setBrowserOrTabActiveTimestamp(new Date());
}
setBrowserOrTabActiveTimestamp(timeStamp: Date) {
localStorage.setItem(
'browserOrTabActiveSessionTimestamp',
`${timeStamp.getTime()}`
);
}
wasBrowserOrTabClosedAfterSignin(): boolean {
const value = localStorage.getItem('browserOrTabActiveSessionTimestamp');
const lastTrackedTimeStampWhenAppWasAlive = value
? new Date(Number(value))
: null;
const currentTimestamp = new Date();
const differenceInSec = moment(currentTimestamp).diff(
moment(lastTrackedTimeStampWhenAppWasAlive),
'seconds'
);
// if difference between current timestamp and last tracked timestamp when app was alive
// is more than 15sec (if user close browser or all opened *your app* tabs more than 15sec ago)
return !!lastTrackedTimeStampWhenAppWasAlive && differenceInSec > 15;
}
How it works:
If the user closes the browser or closes all opened your app tabs then after a 15sec timeout - logout will be triggered.
it works with multiple windows open
no additional load on the server
no problem with F5 / refresh
Browser limitations are the reason why we need 15sec timeout before logout. Since browsers cannot distinguish such cases: browser close, close of a tab, and tab refresh. All these actions are considered by the browser as the same action. So 15sec timeout is like a workaround to catch only the browser close or close of all the opened your app tabs (and skip refresh/F5).
I posted this originally here but I will repost here for continuity.
There have been updates to the browser to better tack the user when leaving the app. The event 'visibilitychange' lets you tack when a page is being hidden from another tab or being closed. You can track the document visibility state. The property document.visibilityState will return the current state. You will need to track the sign in and out but its closer to the goal.
This is supported by more newer browser but safari (as we know) never conforms to standards. You can use 'pageshow' and 'pagehide' to work in safari.
You can even use new API's like sendBeacon to send a one way request to the server when the tab is being closed and shouldn't expect a response.
I build a quick port of a class I use to track this. I had to remove some calls in the framework so it might be buggy however this should get you started.
export class UserLoginStatus
{
/**
* This will add the events and sign the user in.
*/
constructor()
{
this.addEvents();
this.signIn();
}
/**
* This will check if the browser is safari.
*
* #returns {bool}
*/
isSafari()
{
if(navigator && /Safari/.test(navigator.userAgent) && /Chrome/.test(navigator.userAgent))
{
return (/Google Inc/.test(navigator.vendor) === false);
}
return false;
}
/**
* This will setup the events array by browser.
*
* #returns {array}
*/
setupEvents()
{
let events = [
['visibilitychange', document, () =>
{
if (document.visibilityState === 'visible')
{
this.signIn();
return;
}
this.signOut();
}]
];
// we need to setup events for safari
if(this.isSafari())
{
events.push(['pageshow', window, (e) =>
{
if(e.persisted === false)
{
this.signIn();
}
}]);
events.push(['pagehide', window, (e) =>
{
if(e.persisted === false)
{
this.signOut();
}
}]);
}
return events;
}
/**
* This will add the events.
*/
addEvents()
{
let events = this.setupEvents();
if(!events || events.length < 1)
{
return;
}
for(var i = 0, length = events.length; i < length; i++)
{
var event = events[i];
if(!event)
{
continue;
}
event[1].addEventListener(event[0], event[3]);
}
}
/**
*
* #param {string} url
* #param {string} params
*/
async fetch(url, params)
{
await fetch(url,
{
method: 'POST',
body: JSON.stringify(params)
});
}
/**
* This will sign in the user.
*/
signIn()
{
// user is the app
const url = '/auth/login';
let params = 'userId=' + data.userId;
this.fetch(url, params);
}
/**
* This will sign out the user.
*/
signOut()
{
// user is leaving the app
const url = '/auth/logout';
let params = 'userId=' + data.userId;
if(!('sendBeacon' in window.navigator))
{
// normal ajax request here
this.fetch(url, params);
return;
}
// use a beacon for a more modern request the does not return a response
navigator.sendBeacon(url, new URLSearchParams(params));
}
}