Question

Upon successful login, I’m saving the session variable.

When the user goes to different pages in the app, the session is gone even though I didn’t explicitly destroy the session. How do i fix this?

Here is a page where the session appears to disappear.

<?php
include 'core/init.php';
include 'core/sendmessage.php';
$user_info = $_SESSION['user_id'];
$getUser = mysql_query("SELECT * FROM users WHERE user_id = ".$uid);

$user_info = array();

while($currentRow = mysql_fetch_array($getUser)){
    $user_info['firstname'] = $currentRow['first_name'];
    $user_info['lastname'] = $currentRow['last_name'];
    $user_info['username'] = $currentRow['username'];
}
?>

Within core/init.php I have the session start method.

<?php
session_start();
require 'database/connect.php';
require 'functions/users.php';
require 'functions/general.php';

if (logged_in() === true) { 
$user_data = user_data($_SESSION['user_id'],'first_name','last_name','username');
}

$errors = array();
?>

Answer 1

session_start() creates a session or resumes the current one based on a session identifier passed via a GET or POST request, or
passed via a cookie. (Visit PHP: session_start)

Add session_start() on the beginning of each page (after your <?php tag).

In your case:

<?php
if(!isset($_SESSION)) session_start(); //--> ADD this line

include 'core/init.php';
include 'core/sendmessage.php';
$user_info = $_SESSION['user_id'];

...