I have an online game. I wish to show how many user are online. The problem is to know when a user is offline.
Is there a way to perform a check on sessions cookie to acknowledge whether the session with the broswer was closed?
I was thinking about simply set a timeout on the server which launch a script that count how many session cookie are present, but how do I check if the session cookie is about somebody who's logged and not just a visitor?
How did you handle this?
1) I don't want to rely on a script fired with the logout button, since nobody ever logout... people simply close the browser.
2) About timestamps and registering activity? Since in my game users interact with an svg (not moving through pages), they generate a huge amount of clicks. Making a query for each click for each of them refreshing a record would be very expensive.
When the user interacts with the site, set their last activity time.
If it is longer than 30 mins or so, you can assume they are offline.
You can also explicitly set someone to offline when they click logout.
However, your case is a little different. You could use a heartbeat style script.
Whilst they are on the page, use setInterval() to extend the expiry date, up to a maximum range (in case the user leaves their browser window open for hours on end).
Since your code gets executed when the page is loaded you cannot make a check if the user closed his browser or not.
So the common approach would be to use timestamps and update this stamp if the user does something on your site and if the timestamp is older than say 5 minutes you just assume he is offline
Related
I am keeping a list of active users of my web site.
When user logs in I add them to the list.
Then I periodically (on timer) call a PHP script which delays PHP session expiration time on the server each time by 10 mins.
When users logs out I remove them from the active users list.
As timer is stopped and an expiration is not delayed anymore, a PHP session expires after 10 mins.
So far so good.
When user closes a browser without logging out, their session still expires after 10 mins as a time stamp is not updated anymore.
But this user still remains in my active users list !!
How can I remove this user?
I am keeping this list in order to prevent users from entering from 2 computers simultaneously, that is a client requirement.
EDIT:
I am sure that this can be done as bank sites, ticket sites etc. somehow cope with this problem.
The simple answer is you can't. Not with PHP alone anyway. If you are happy to force javascript usage, you could write a script which would 'poll' the server from the user's browser on very regular intervals to let it know the user was still active.. you would then also reduce the interval set for your PHP script to keep things updated with more accuracy.
You could try updating the "active users" list on a more frequent basis, but it would generally make more sense to clear a user's session data upon each login. Therefore, if a second login occurs from another computer, the first one is terminated upon the next page load.
I have a problem with logged in users closing their browsers.
My code can't run due to the browser closing and so their logonstatus cant update to 'N' in the database. Also due to the session being destroyed they cant go back to the main pages as I have this code if (!isset($_SESSION['logged in'])) { etc to prevent people from viewing any pages without logging in.
When a user logs on their logonstatus changes to 'Y' and I record the time they logged in.
I record their lastactivity time on each page load.
I redirect users to the login page and change their logonstatus if they have been idle for 20 min on a page.
I also have a cron job due to the browser close issue which runs every 5 minutes and checks if the users last activity has been longer than 20 min and if so their logonstatus becomes 'N'
I think users having to wait 20+ min to re-login due to browser close is too long and so I would like to make it possible to login in again straight away.
I have read about the unload functions of javascript but apparently it is unreliable.
Is there any other way I could go about this?
Closing the browser is always a client side action. So you will need javascript to send the action to the server for PHP to do something.
You can use onbeforeunload to send something to the server, but it is indeed unreliable. A more reliable method is to make the session time a lot shorter (eg: 2min) and then have an ajax call every 30seconds to the server to keep the session alive (make sure its a page with a very small impact on server/connection). If the request fails 4 times, the session is destroyed. Now your cronjob can run every 2mins and a user only has to wait that long.
Another approach is to store a cookie on the users computer with a GUID and save it in the database with the "Logged ='Y'". Now when somebody tries to log in to an account which is already logged in, check if its the same user (cookie) and if so, allow it.
This still makes it possible for one user to log in twice, just harder and not by mistake.
You need to change the duration of your session cookies so that they last as long as the browser window remains open; do this with session_set_cookie_params, setting the lifetime to 0. Don't forget to make sure that your cron script and PHP's session gc max lifetime don't delete sessions before 20 minutes have passed.
Since you keep a record of their last access time and check it on each request, you can continue to log out people after 20 minutes of inactivity (just destroy their session and redirect to the login page).
I'm running a php login script on my server. Whenever a user logs in the username is stored in $_SESSION['username'] and there exists a field in one of my DB tables called nonline used to store the number of users logged in.
When a user logs in, the value of nonline increases by one. And whenever a user logs out it decreases by one. Pretty neat so far. :P
The problem starts when, most of the users, like me, do not click logout, or visit the logout page as such. They log in, and just close their browser/tab when done. Doing so doesn't decrease the nonline value. So the value remains as such, even when the user is no more browsing my website.
Is there any way I can determine the number of users actually looking at my website at any given time so that its value changes even when a user closes his browser instead of clicking logout? I'm not using cookies for login.
Normally this will be done with a table which tracks last action, or last page load. The number n_online (you may want to add the _, noline starts with no, which is a little odd at first glance) will be the number who have made some form of action in the last n seconds - the number of people who actively logged out.
Unfortunately, there is not. Any solution that does what you want would involve the browser firing an HTTP request of some kind when the tab/window is closed, and this isn't going to happen.
The best you can do is have the users' sessions time out after a relatively short time (e.g. 15 minutes) and perform aggressive cleanup of expired sessions on every script that wants to know the actual number of active users. Be aware that this will be bad for performance.
If 15 minutes is still too long for you and you cannot decrease the session lifetime (because it would annoy your users if they were logged out after 10 seconds of inactivity), you can have your pages "ping" the server using AJAX to keep the session alive. This will allow you to have almost real-time results, but it will probably kill your performance, it will not work for users with JavaScript disabled, and is prone to malfunction if a user experiences transient connectivity problems.
heres a issue i have. When a user logs in on the website, it sets a value to indicate they are offline. If they logout through the website, the value is set to indicate the user is offline.
But if the user just closes the website without pressing logout, it still indicates they are online.
How can i make it so it makes them offline once they have closed the website.
my website is using php, html, css and mysql.
The most common approach is to save a timestamp with the user's last activity instead of just an "online" flag. Update the timestamp on every activity and calculate offline users by checking for users which have been inactive for more than, say, five minutes.
For performance reasons you may want to save the timestamp into the users current session as well and only update your activity timestamp in the database when it is about to expire.
Since closing a browser (or a browser tab) doesn't fire any events to your server, basically you can't react to this. In such a case I'd prefer a heartbeat mechanism.
Another way is to "assume" the client has logged out if he hasn't fired any event since lets say 20mins or so.
A similar issue has been discussed here: Check if user is offline
You can check for user are "answering" by Ajax for example. Or you can set status offline by inactivity timeout.
perhaps there is some javascript event when browser closes, on which you could using ajax send notification to the server.
A better approach i would guess is to have client's javascript to periodically notify server that user is still there. Once notification is not received - he must be offline.
I would like to store the login, logout and duration time in database.
The login time is created when the user is authenticated(successfully logged in)
The logout time is created when the user clicks the logout button
The duration is logout - login time. (logout minus login)
But the problem is, what if the user didnt click the logout button. Here are the situations:
Internet loss
Close the browser/tab. (I need this must use javascript, but i donnu how to do it, any idea?)
EDIT:
I forgot to add something to the question, the program is a full flash program, there is no navigation to other page. Only 1 page
It's important to remember that all session/log-in functions in PHP are usually cookie based. So, changing the lifetime of the session cookie should solve your problem:
http://us3.php.net/manual/en/function.session-set-cookie-params.php
Also, you can set the PHP sessions so they only use cookies:
http://us2.php.net/manual/en/session.configuration.php#ini.session.use-only-cookies
Again, you can catch the browser window / tab close but ... why? For instance I may have your site open in multiple tabs. If I close one of those tabs should I automatically be logged out of your website? That's a very bad design. Instead, set the session lifetime so it expires if the browser is closed and not just a tab. (Note also that window.unload will logout when any window on your site that closes - including a pop-up or an iframe. Do you really want that?)
http://us2.php.net/manual/en/session.configuration.php#ini.session.cookie-lifetime
If you want to store session state in a database try any one of these guides. Or, roll your own with session_set_save_handler
You can't rely on receiving an event for the user logging out, if they simply close their browser, or disappear from the internet.
In this case you'll have to have a session timeout of some kind, and record the logout when your app realises their session is too old.
If this is a real requirement, then I'd say you need a "cron" job monitoring the sessions for timeout. When a session has timed out, if the were logged on, it then records a "logout" event for that user.
Note that you can't use (for example) ASPNET's Session_End event, because that won't be reliably called either (for example if the server process restarts).
Another option is to add the logout time next time that user logs on - when they log on, you check for old sessions and assume that any which weren't closed lasted for a fixed amount of time since the last page hit.
That's really all you can do.
Regarding the closing of browser/tab, you can bind the unload event (window.onunload, jQuery's $(window).unload(fn), or any other) to notify your server. A more general purpose solution would be to periodically ping your server (say, every 5 min), but it might be annoying to the user, so do so judiciously.