CODEWITHSUNDEEP
phpmysqldatabase-design
trerums
trerums

Reputation: 397

How to implement "is user online" feature like in FB?

I can't design mysql tables for "is user online" feature. Googled but can't find concrete solutions. Any help would be appreciated. Thank you.

Upvotes: 1

Views: 1440

Answers (3)

Mattis
Mattis

Reputation: 5096

You can build on something like this:

Create a tblOnline table with the following fields

id int not null auto_increment primary key
colSession text
colStamp int

When someone login you create a session variable for them:

session_start();
$_SESSION['online'] = md5(uniqid(rand(), true)); // Create a unique string

Store the unique session in tblOnline:

$stamp = time();
mysql_query('INSERT INTO tblOnline (colSession,colStamp) VALUES ('.$_SESSION['online'].','.$stamp.')');

When they do something (like, the page reloads) update the colStamp with the current timestamp:

$now = time();
mysql_query('UPDATE tblOnline SET colStamp = '.$now.' WHERE colSession = '.$_SESSION['online'].'');

To get all the online users do something like:

$timecheck = time()-(60*5); // 5 minutes back
$rs = mysql_query('SELECT * FROM tblOnline WHERE Stamp > '.$timecheck.'');
$num = mysql_num_rows($rs);
echo "There are: ".$num." users online right now!";

Clean up old session data from the database from time to time (matching on colStamp of course):

$timeclean = time()-(60*60); // One hour back
mysql_query('DELETE FROM tblOnline WHERE Stamp < '.$timeclean.'');

Upvotes: 1

Rufinus
Rufinus

Reputation: 30741

  1. Store the Session in the DB, store the user_id as extra field in the session table.

  2. query session table for open sessions

But be aware that sessions are not a 100% representation of users which are really on the site. (session timeouts).

Upvotes: 3

daniel.herken
daniel.herken

Reputation: 1105

One possibility would be to save the last action of every user in your database (as timestamp) and say "every user who performed some action in the last 2 minutes is online".

If you updated this with ajax for example, you will be able to track who closed the page and who not.

Upvotes: 4

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