Current people online counter

Ramsey_Nasser

i was wondering how you could make a counter that shows how many people are currently on the site. i was thinking of having a one-cell MySQL database for the number, incrementing whenever someone comes in and decrementing when he leaves. thats all pretty easy, but i wasnt sure how to trigger the decrement. i thought of using JavaScript's onUnload event, but i was never too good at JS...

Any ideas?

planetsim

No no and no.. Dont go for that approach..

This is what i did.. and it kinda is exactly the same as this tutorial http://www.spoono.com/tutorials/php/users_online/ ..

Now from that tutorial.. You need specific things..

What i used the one i made for was with a forum that is still in progress so i used sessions,cookies to work it out..

So we gonna need to get a timestamp..

so i use time();

So we will varify the time.. Cos the way you are doing it will never decrease but increase even if theres noone on the site

$time=time();
$timeout=$time-300;//300 is seconds so its 5mins..

//then well insert the new person into the database..
well get there IP so we can varify later how many people are online.. (This is good if you dont have sessions or cookies..)

mysql_query("INSERT INTO users_online(id,time,ip) VALUES('NULL','$time','$REMOTE_ADDR')");

//that just inserts to the db.. now to get the users_online

$result=mysql_query("SELECT DISTINCT ip FROM users_online");
$num=mysql_num_rows($result);
//display results

//from there we wont to delete users past the $timeout.. so we do this

mysql_query("DELETE FROM users_online WHERE time < $timeout");
//that deletes rows that are more than 5mins old..

Now i just wrote that in 10mins i think.. So its not a really hard script.. But you came from the wrong direction.. So thats maybe why you didnt know what to do..

trooper

There is one fundamental potential problem with th code above (happens to us all 😃 ).

If someone is on the site for more than 5 mins then you would lose them in your "how many users online" check.

Ramsey_Nasser

trooper has a point...

i was thinking of having JavaScript open a page in a new window that would decrement the variable in the database then close. somthing like:

<?php

mysql_connect(localhost,user,password);
mysql_query("use database");
mysql_query("update counter set current = current-1");

?>

<html>
<body onLoad="slef.close">

some text here maybe

</body>
</html>

would that work?

planetsim

Thats the whole point.. If they go offline then off course you'd lose them..

But all you need to do is change the timeout.. function instead of 5mins make it 0 or whatever you want...

I dont think Javascript can count how many people are online.. Cos its client side.. Meaning that if there were 2people online.. They'd only count 1.. But i could be wrong.. The thing is how are you suppose to count that user with Javascript..

Ramsey_Nasser

planetsim, the problem with ur aproach is if they stay online more than 5min (or whatever the timeout is), then u lose them. people can stay on for more than whatever u set the timeout to.

i wasnt thinking of using JavaScript to actually count the people(like u said, its client side, so it wouldnt work), i wanted to use it to trigger a PHP script that would handle the counter.

planetsim

If you put that on everypage you wouldnt lose anyone
yes rows will be deleted but if people are there and they keep moving more rows will be inserted with there IP.. There IP in this case is the Primary Key.. (Dont set it as the primary key though) We can select.. There IP from Distinct meaning if theres 2 Ip's the same thats 1... So 1 Person Online

Does that help

Ramsey_Nasser

lets say, for example, that some one goes on the site and decides to stay on the first page without moving for more than the timeout. he wouldnt be counted any more as a person currently online.

another problem is if some one goes on, then goes off the site immidiatly. he will continue to be counted until the timeout is reached.

planetsim

I hate to tell you this.. What do you think VBulletin Forums use.. This is a VB forum...

Thats the Approach.. If you know of away with Javascript use it..
But if a person is on page more than 5mins.. they'll be counted as soon as they move on.. Most people wont stay on a page more than 5-10mins

Ramsey_Nasser

so thats the only way? hmmm..... thx for the help

planetsim

Well yes.. Unless you can figure a way to find this out with PHP then parse the Javascript results + 1 in the database..

But its a pretty bad way of doing it.. There would be lines of code.. Lots of errors everywhere.. I cant imagine it really getting far..

Thats why i use it.. You could also integrate cookies to help out.. Like maybe change the timeout.. And set it in the cookie.. But it will work similar.. You will still need the database to count all the rows get the distinct ip then return the results