How many users online

[Jaan]

Hey!

Now I'll show you how to see how many users are browsing your website. There are many ways to display it but I'm trying to keep it simple and clean.

First of all we have to create a two tables to your database.

[highlight="sql"]
CREATE TABLE `uonline` (
`session` varchar(100) NOT NULL,
`time` int(5) NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
[/highlight]

It will create two tables. One is session and other is time. They are going to store our information.

Now it's time for PHP. Let's create our main variables

<?php
session_start();
$ses = session_id();
$time = time();
$timech=$time-300;

session_start(); - This wills start a session
$ses = session_id(); - This will get our session's ID
$time = time(); - This will get the time
$timech=$time-300; - This will set our time to 5min

Now we have to connect to the database:

// Declare SQL login info
$host = "localhost";
$username = "";
$password = "";
$dbname = "";

// Now we are going to connect to our database
mysql_connect("$host", "$username", "$password")or die("<font style='color:red'><b>Can not connect:</b> ".mysql_error()."</font>");
mysql_select_db("$db_name")or die("<font style='color:red'><b>Can not select the database:</b> ".mysql_error()."</font>"); 

$host = "localhost"; - Your SQL's host name, usually it's "localhost"
$username = ""; - Your MySQL username
$password = ""; - Your MySQL password
$dbname = ""; - Your database's name

Now we have to look for existing sessions and get the number of sessions.

$result = mysql_query("SELECT * FROM uonline WHERE session='$ses'");
$num = mysql_num_rows($result); 

$result = mysql_query("SELECT * FROM uonline WHERE session='$ses'"); - This will select all info from session column where it's value is "$ses"
$num = mysql_num_rows($result); - It will tell us how many active records are in session column

if($num == "0"){
$result1 = mysql_query("INSERT INTO uonline (session, time)VALUES('$ses', '$time')");
}else{
$result2 = mysql_query("UPDATE uonline SET time='$time' WHERE session = '$ses'");
} 

if($num=="0"){ - If there's no records in session column then we must insert some records
$result1 = mysql_query("INSERT INTO uonline (session, time)VALUES('$ses', '$time')"); - Inserts session's ID and time to database
}else{ - But if there was more records than 0, let's update their records
$result2 = mysql_query("UPDATE uonline SET time='$time' WHERE session = '$ses'"); - Updates existing records
} - Ends If statement

Now let's find our info again from the columns:

$result3 = mysql_query("SELECT * FROM uonline"); 

$result3 = mysql_query("SELECT * FROM uonline"); - This will get all info from uonline table

It's time for showing how many users are looking your site:

$usersonline = mysql_num_rows($result3);
echo "There are: <b>".$usersonline."</b> users online"; 

$usersonline = mysql_num_rows($result3); - It will get the number of records in columns
echo "There are: <b>".$usersonline."</b> users online"; - This will show how many users are on your site

When the users have left, you must delete their records from database.

mysql_query("DELETE FROM uonline WHERE time<$timech");
?> 

mysql_query("DELETE FROM uonline WHERE time<$timech"); - Deletes records from database when 5min has been thru.

And here's the full code:

<?php
session_start();
$ses = session_id();
$time = time();
$timech=$time-300; 

$host = "localhost";
$username = "";
$password = "";
$dbname = "";

mysql_connect("$host", "$username", "$password")or die("<font style='color:red'><b>Can not connect:</b> ".mysql_error()."</font>");
mysql_select_db("$db_name")or die("<font style='color:red'><b>Can not select the database:</b> ".mysql_error()."</font>");  

$result = mysql_query("SELECT * FROM uonline WHERE session='$ses'");
$num = mysql_num_rows($result); 

if($num == "0"){
$result1 = mysql_query("INSERT INTO uonline (session, time)VALUES('$ses', '$time')");
}else{
$result2 = mysql_query("UPDATE uonline SET time='$time' WHERE session = '$ses'");
} 

$result3 = mysql_query("SELECT * FROM uonline"); 

$usersonline = mysql_num_rows($result3);
echo "There are: <b>".$usersonline."</b> users online";  

mysql_query("DELETE FROM uonline WHERE time<$timech");
?>

[Xav]

Thanks for the advice. If you can't be bothered to write the code, there are lots of ready-made scripts available on the internet.

[Jaan]

yes there are.. BUT when you're making your own..then it's feel much better..

[Xav]

Good point. Now you think about it - what's the point of having a programming forum if no-one bothers to program? I'll never forget that first moment of joy when my very first application worked. It was just a button that popped up with a message, then exited, but hey - everyone's gotta start somewhere.

[Jaan]

lol yes..
well.. i usually make all codes that i need myself.. because.. in my script.. i know where everything is.. but in already finished script i don't know.. where's this or that.. well.. when i want to customize it a little.. and when you make your own programs.. then you will learn very much..

[Xav]

Very true, very true.

[phpforfun]

is it possible to add the usernames to the database, when they exit out of the browser, it will remove them from the list? this way we could make a chat of some sort

[Xav]

Oh, just get one off the internet. You can always customise it later!

[John]

is it possible to add the usernames to the database, when they exit out of the browser, it will remove them from the list? this way we could make a chat of some sort

Yes, the method Jaan described above can be modified in several ways to meet your needs - especially since it relies on a database to store the sessions. However, if you simply want to count the amount of registered sessions, reading/writing/updating a database many times can be costly - another faster (20 times faster) method would be to just read the amount of session files that are in the servers session directory (amount of session files = amount of registered sessions). This method is more efficient for counting the amount of users, however if you want to "track" users, then using a database is a must.

[seyz4all]

this can be helpful