Detect If PHP Session Exists

Detect if PHP session exists

If $_SESSION (or $HTTP_SESSION_VARS for PHP 4.0.6 or less) is used, use isset() to check a variable is registered in $_SESSION.

isset($_SESSION['varname'])

How can you check if a PHP session exists?

In PHP versions prior to 5.4, you can just the session_id() function:

$has_session = session_id() !== '';

In PHP version 5.4+, you can use session_status():

$has_session = session_status() == PHP_SESSION_ACTIVE;

Check if session exists in php

Use isset function

function ifsessionExists(){
// check if session exists?
  if(isset($_SESSION)){
    return true;
  }else{
    return false;
  }
 }

You can also use empty function

 function ifsessionExists(){
// check if session exists?
  if(!empty($_SESSION)){
    return true;
  }else{
    return false;
  }
 }

Check if PHP session has already started

Recommended way for versions of PHP >= 5.4.0 , PHP 7, PHP 8

if (session_status() === PHP_SESSION_NONE) {
    session_start();
}

Reference: http://www.php.net/manual/en/function.session-status.php

For versions of PHP < 5.4.0

if(session_id() == '') {
    session_start();
}

Determine if $_SESSION superglobal exists in PHP

if (isset($_SESSION['errors']))
{
    //Do stuff
}

Check to see if PHP session exists not working

You need to add

<?php session_start(); ?>

on each page in the very beginning..

So, the code should be like this

<?php 
  session_start();
  if (!isset($_SESSION["name"]))
   {
      //header("location: delete1.php");
      die('<meta http-equiv="refresh" content="0;URL=\'delete1.php\'" />');
   }
   else{
   }
?> 

How do check if a PHP session is empty?

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.

Check if session exists php and print an 'echo'

In your second php file you want to access $_SESSION. You need to add

session_start(); 

at the begin of your file.

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