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

Answer 1

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 2

I know this is old, but I ran into an issue where I was running a function after checking if there was a session. It would throw an error everytime I tried loading the page after logging out, still worked just logged an error page. Make sure you use exit(); if you are running into the same problem.

     function sessionexists(){
        if(!empty($_SESSION)){
     return true;
         }else{
     return false;
         }
      }


        if (!sessionexists()){
           redirect("https://www.yoursite.com/");
           exit();
           }else{call_user_func('check_the_page');
         } 

Answer 3

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 4

if(isset($_SESSION))
{}
else
{}

Answer 5

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 6

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).