How to hide login form after login

Question

I am new to PHP. So I made a loginform for my website and where I'm having trouble hiding the form after the user logs in.. I want it to disappear after the user sucessfully logs in. My code is the following,

<?php
    include "connect.php";
    $_SESSION['backurl'] = basename($_SERVER['PHP_SELF']);
?>

<div class = "loginform">  
            <form name = "login" action = "login.php" method = "post" accept-charset = "utf-8"> 
                <?php
                     echo $_SESSION['username'];
                    //IF LOGADO TIRAR FORM. 
                ?>
                <ul>  
                    <li><label for = "usermail" class = "letralogin" >Email</label>  
                    <input type = "email" name = "usermail" placeholder = "yourname@email.com" required></li> 
                    <p>
                    <li><label for = "password" class = "letralogin">Password</label>  
                    <input type = "password" name = "password" placeholder = "password" required></li> 
                    <p>                 
                    <input type = "submit" name = "login" value = "Login"></li>
                </ul>                   
            </form>
            </div>

            <div class = "divreg">
                <input type = "button" onclick = "location.href = 'registo.php';" value = "Registo" class = "buttreg"/>
            </div>

This is my code on login.php,

<?php
    include "connect.php";
    if(isset($_POST['login']))
    {
        $username = $_POST['usermail'];
        $password = sha1($_POST['password']);
        $sql = "select * from utilizador where email = '$username' and password = '$password'";
        $result = mysqli_query($conn, $sql);
        if (mysqli_num_rows($result) > 0)
        {
            echo 'OK';
            $_SESSION['username'] = $username;
            header('Location: ' . $_SESSION['backurl']);
        }
        else 
        {
            echo 'wrong password';
            header('Location: ' . $_SESSION['backurl']);
        }
    }
    else
    {
        header('Location: inicio.php');
    }
?>

Answer 1

You can check session in login file at top:

include "connect.php";

session_start();

    $_SESSION['backurl'] = basename($_SERVER['PHP_SELF']);

if(isset($_SESSION['username']) && !empty($_SESSION['username']) )   {
       header('Location: ' . $_SESSION['backurl']);
}

If you have both separate files than you need to use session_start function in both files.

Answer 2

Assuming the username session variable is only set if the user is logged in, this would be what you want.

if (!isset($_SESSION['username'])) {
?>
HTML FORM CODE GOES HERE
<?php
}
?>

What this does is check if you have a username set, and if you don't it will display the HTML for the login form if you place it between the PHP tags. Additionally you could put a bit of JavaScript in there that hides your loginform div, which would also remove the login form from the page.

Answer 3

You should check that your session is empty or not. Like this:

session_start();
if(!empty($_SESSION['username']) {
       ?>
       <!--your login form-->
       <?php
} else {
       ?>
       main page.
       <?php
}

this is for the situation that you want when the user is not logged in no page be shown for him except Login part. Or if you want just hide login form after logging in, It will be like this:

session_start();
if(empty($_SESSION['username']) {
       ?>
       <!--your login form-->
       <?php
}
?>
<!--main part details. -->

Answer 4

Foreword:

You're presently outputting before header with the echos above your headers, and that alone will kill your code.

Either you echo OR header; you can't have both, not the way you are using them now.

• More on this here: How to fix "Headers already sent" error in PHP

Here is a basic method and as I mentioned in comments, assign a variable to your form code, and encapsulated in quotes.

You can base yourself on the following skeleton/basic model and then take it from there.

<?php 
error_reporting(E_ALL);
ini_set('display_errors', 1);

session_start();

$_SESSION['user'] = "John";
?>

<!DOCTYPE html>
    <head><title></title></head>
    <body>

<?php 


$form = '
            <form name = "login" action = "login.php" method = "post" accept-charset = "utf-8">

                <ul>  
                    <li><label for = "usermail" class = "letralogin" >Email</label>  
                    <input type = "email" name = "usermail" placeholder = "yourname@email.com" required></li> 
                    <p>
                    <li><label for = "password" class = "letralogin">Password</label>  
                    <input type = "password" name = "password" placeholder = "password" required></li> 
                    <p>                 
                    <input type = "submit" name = "login" value = "Login"></li>
                </ul>                   
            </form>

';


if (isset($_SESSION['user']) && $_SESSION['user'] == 'John') {

    echo "Welcome " . $_SESSION['user'];

    }

    else{ 

    echo $form;

    }

?>

    </body>
 </html>