Locking/unlocking a website, e.g. for a landing page that is currently in a beta phase.

coming-soon.html

<h1>Coming Soon</h1>

index.php

<?php

// start the session to be able to read the unlock key
session_start();

// get the unlock key - as fallback the variable contains an empty string
$session_unlock_key = $_SESSION['unlock_key'] ?? '';

// check if the session unlock key is correct
// if not show the landing page
if ($session_unlock_key !== '__YOUR_SESSION_UNLOCK_KEY__') {
  require __DIR__ . '/coming-soon.html';
  exit;
}

// ...

lock.php

<?php

// start the session to be able to remove the unlock key
session_start();

// clear all session variables
session_unset();
// remove all session data
session_destroy();

// redirect to the home directory, this will be in our case the index.php file
header('Location: /');

unlock.php

<?php

// start the session to be able to set the unlock key
session_start();

// set the unlock key
$_SESSION['unlock_key'] = '__YOUR_SESSION_UNLOCK_KEY__';

// redirect to the home directory, this will be in our case the index.php file
header('Location: /');