How do check if a php session is empty?

Question

Is this bad practice?

if($_SESSION['something'] == '') {

    echo 'the session is empty';

}

Is there a way to check if a its empty or b it is not set? e.g something better than...

if(     $_SESSION['something'] == ''  ||    !isset($_SESSION['something'])   )  {

    echo 'the session is either empty or doesn't exist

}

OR does !isset just see if a $_SESSION exist and doesn't matter if there are values in the array?

Thanks for helping a newbie

Answer 1

you are looking for PHP’s empty() function

Answer 2

You could use the count() function to see how many entries there are in the $_SESSION array. This is not good practice. You should instead set the id of the user (or something similar) to check wheter the session was initialised or not.

if( !isset($_SESSION['uid']) )
    die( "Login required." );

(Assuming you want to check if someone is logged in)

Answer 3

I would use isset and empty:

session_start();
if(isset($_SESSION['blah']) && !empty($_SESSION['blah'])) {
   echo 'Set and not empty, and no undefined index error!');
}

array_key_exists is a nice alternative to using isset to check for keys:

session_start();
if(array_key_exists('blah',$_SESSION) && !empty($_SESSION['blah'])) {
    echo 'Set and not empty, and no undefined index error!');
}

Make sure you're calling session_start before reading from or writing to the session array.

Answer 4

Use isset, empty or array_key_exists (especially for array keys) before accessing a variable whose existence you are not sure of. So change the order in your second example:

if (!isset($_SESSION['something']) || $_SESSION['something'] == '')

Answer 5

If you want to check whether sessions are available, you probably want to use the session_id() function:

session_id() returns the session id for the current session or the empty string ("") if there is no current session (no current session id exists).