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 its empty or it is not set? I'm actualy doing this:

if (($_SESSION['something'] == '') || (!isset($_SESSION['something'])) {
    echo 'the session is either empty or doesn\'t exist';
}

Does !isset just checks if a $_SESSION[''] exist and doesn't check if, is there are values in the array or not

1
41
5/4/2013 11:48:27 AM

Accepted Answer

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.

88
12/31/2017 7:25:31 AM

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'] == '')

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