How do I use a $_SESSION['variable'] from one session in another? - php

Question

I'm making a web app where the user logs in and is able to access the profile and take a quiz. I've got most of it working the only problem is, is that it seems to 'forget' which user is signed in. By this I mean I can't access any of the variables from when the user logs in session.
For example, I have a $_SESSION['username'] = $username; which returns unidentified variable when I try to use the variable $username in a different session or page. Also, I haven't terminated my login session.
Right now I'm trying to store the results of my quiz to a database along with the user's username but it only stores the score and not the username.
Below is my code.
authenticate.php file (This contains the variables regarding usernames)
<?php
session_start();
// Change this to your connection info.
$DB_HOST = 'localhost';
$DB_USER = 'root';
$DB_PASS = '';
$DB_NAME = 'phplogin';
// Try and connect using the info above.
$con = mysqli_connect($DB_HOST, $DB_USER, $DB_PASS, $DB_NAME);
if ( mysqli_connect_errno() ) {
// If there is an error with the connection, stop the script and display the error.
die ('Failed to connect to MySQL: ' . mysqli_connect_error());
}
// Now we check if the data was submitted, isset will check if the data exists.
if ( !isset($_POST['username'], $_POST['password']) ) {
// Could not get the data that should have been sent.
die ('Username and/or password does not exist!');
}
// Prepare our SQL
if ($stmt = $con->prepare('SELECT username, password FROM users WHERE username = ?')) {
// Bind parameters (s = string, i = int, b = blob, etc), hash the password using the PHP password_hash function.
$stmt->bind_param('s', $_POST['username']);
$stmt->execute();
$stmt->store_result();
// Store the result so we can check if the st_account exists in the database.
if ($stmt->num_rows > 0) {
$stmt->bind_result($username, $password);
$stmt->fetch();
// st_account exists, now we verify the password.
if (password_verify($_POST['password'], $password)) {
// Verification success! User has loggedin!
$_SESSION['loggedin'] = TRUE;
$_SESSION['name'] = $_POST['username'];
$_SESSION['username'] = $username;
include_once 'homepage.php';
// echo 'Welcome ' . $_SESSION['name'] . '!';
} else {
echo 'Incorrect username and/or password!';
}
} else {
echo 'Incorrect username and/or password!';
}
$stmt->close();
} else {
echo 'Could not prepare statement!';
}
?>
final.php file
<php include "process.php"?>
lines 24 - 44
<main>
<div class="container">
<h2>You are Done!</h2>
<p>Congrats! You have completed the test</p>
<p>Final score: <?php echo $_SESSION['score']; ?></p>
<?php echo $score; ?>
Take Test Again
<?php
$DB_HOST = 'localhost';
$DB_USER = 'root';
$DB_PASS = '';
$DB_NAME = 'phplogin';
$con = mysqli_connect($DB_HOST, $DB_USER, $DB_PASS, $DB_NAME);
$query = "INSERT INTO `results`(`username`,`score`) VALUES ($username, $score)";
mysqli_query($con, $query);
?>
<?php session_destroy(); ?>
</div>
I don't know if it's necessary to include process.php but I thought it might be helpful to show where the $score variable comes from.
process.php file (this isn't the whole file.)
<?php include 'database.php'; ?>
<?php session_start(); ?>
<?php
//Check to see if score is set_error_handler
if (!isset($_SESSION['score'])){
$_SESSION['score'] = 0;
}
$score = $_SESSION['score'];
}
?>
Sorry if I've made a really simple stupid error, don't hate me, I'm still pretty bad at coding.

Answer 1

Put your session_start(); at the very top of your code, for example, at the very top of your final.php file rather than in your process.php file.
E.g.;
<?php
session_start();
include 'database.php';
?>

Answer 2

A simple solution that you can try
session_start();
We have to add this on the top of php file, or else php throw exceptions like 'headers already sent' or 'can’t start the session' etc.