Check if SESSION exists after login

Hello,

I have a login page that redirects to my second page after login. The session is created in the login page. In my second page I need to check if there is a valid session, without creating a new one. Is it possible to check it, without adding session_start() in my second page, so that no new session is created?

Here is the code of my login page:

<?php

session_start(); // Creates a session

$_SESSION["username"] = $username;
header("Location: secondpage.php");
?>


Here is the code of my second page:


<?php

session_start(); // How can I remove this line, so that it doesn't create a new session?

if (isset($_SESSION)) {print "session exists";} // Checks if session exists
else {print "session does not exist";}
?>

The function session_start() does not create a "new" session every time it is called; it will check the HTTP request header for existing session data and make it available to your script if it's there. It's required for sessions to work properly.

Hi,

why does session_start(); create a new cookie named PHPSESSID, when I execute the following code?


<?php
session_start();
?>

By default PHP sessions uses cookies and if the session does not exist then session_start() creates a cookie like you are seeing. If the session already exists session_start() uses that cookie.

Thanks,

can I disable that session_start() creates a cookie if it is not on the login page?

My goal is to only give a session cookie to the persons who log in, and those who don't log in shouldn't get one only because I want to check if they have one.

Not really, since the only way you can check $_SESSION is by starting session. But, you can destroy the session if there are no login credentials found. The best way to destroy a session is discussed in the PHP manual here:

http://us2.php.net/manual/en/function.session-destroy.php

Changing:

if (isset($_SESSION))


to

if (isset($_SESSION["username"])) {
// code
}else{

//

}

Should do the trick.

You'll still need session_start() up top which will create a cookie.