PHP $_SESSION 变量未显示值

Question

I'm making a text in the header of the page which holds the name of the user that is logged in. It worked for some time but when i went to do other things, this just stopped. It's like $_SESSION['ime'] is holding an empty value; I'm pretty sure i didn't touch anything related to that.

Here is some code: My main php file:

session_start();

// initializing variables
$username = "";
$email    = "";
$errors = array(); 

// connect to the database
$db = mysqli_connect('localhost', 'root', '', 'audiprojekat');

// REGISTER USER
if (isset($_POST['reg_user'])) {
  $vrsta = "KO";
  $ime = mysqli_real_escape_string($db, $_POST['ime']);
  $prezime = mysqli_real_escape_string($db, $_POST['prezime']);
  $username = mysqli_real_escape_string($db, $_POST['username']);
  $email = mysqli_real_escape_string($db, $_POST['email']);
  $password = mysqli_real_escape_string($db, $_POST['password']);



  // first check the database to make sure 
  // a user does not already exist with the same username and/or email
  $user_check_query = "SELECT * FROM registrovani WHERE username='$username' OR email='$email' LIMIT 1";
  $result = mysqli_query($db, $user_check_query);
  $user = mysqli_fetch_assoc($result);

  if ($user) { // if user exists
    if ($user['username'] === $username) {
      array_push($errors, "Username already exists");
    }

    if ($user['email'] === $email) {
      array_push($errors, "email already exists");
    }
  }

  // Finally, register user if there are no errors in the form
  if (count($errors) == 0) {
    $password = md5($password);//encrypt the password before saving in the database

    $query = "INSERT INTO registrovani (ime, prezime, username, email, password, vrsta) 
              VALUES('$ime','$prezime','$username', '$email', '$password', '$vrsta')";
    mysqli_query($db, $query);
    $_SESSION['username'] = $username;
    $_SESSION['ime'] = $ime;
    $_SESSION['success'] = "You are now logged in";
    header('location: user.php');
  }
}

if (isset($_POST['login_user'])) {
  $username = mysqli_real_escape_string($db, $_POST['username']);
  $password = mysqli_real_escape_string($db, $_POST['password']);

  if (empty($username)) {
    array_push($errors, "Username is required");
  }
  if (empty($password)) {
    array_push($errors, "Password is required");
  }

  if (count($errors) == 0) {
    $password = md5($password);
    $query = "SELECT * FROM registrovani WHERE username='$username' AND password='$password'";
    $results = mysqli_query($db, $query);
    if (mysqli_num_rows($results) == 1) {
      $_SESSION['username'] = $username;
      $_SESSION['ime'] = $ime;
      $_SESSION['email'] = $email;
      $_SESSION['success'] = "You are now logged in";
      header('location: user.php');
    }else {
        array_push($errors, "Wrong username/password combination");
    }
  }
}

?>

this is the html page:

<?php include('server.php'); ?>
<p id="user_cont" style="color: white;  margin-left: 80%; margin-top: 0; margin-bottom: 0; width: 20%; background-color: black; padding: .5%; font-family: 'Rajdhani', sans-serif; font-size: 140%; border-left: thick red solid;">
                <?php
                    if(isset($_SESSION['username'])){
                        echo $_SESSION['ime'];
                        echo " <a href='logout.php' style='color: red; text-decoration: none;'>Odjavite se</a>";
                    }
                    else echo " <a href='login.php' style='color: white; text-decoration: none;'>Prijavite se</a>";

                ?>

            </p>

$_SESSION['username'] and $_SESSION['password'] is okay but $_SESSION['ime'], $_SESSION['prezime'], $_SESSION['email'] are empty.

I checked mySQL database and everything is written correctly.

Answer 1

Your program had 2 steps, 1. reg_user, 2. login_user

I think you are saying some parameters are empty after logged in to your page. However, you did not read your data from Select query.

Sample code to read from query and store SESSION data:

$row = $results->fetch_assoc();
$_SESSION['ime'] = $row['ime'];
$_SESSION['email'] = $row['email'];
$_SESSION['prezime'] = $row['prezime'];

Reference: https://www.w3schools.com/php/func_mysqli_fetch_assoc.asp

At last, please read more about SQL injection either PDO or MYSQLI.