plateforme-tfjm2/server_files/controllers/deconnexion.php

<?php

unset($_SESSION["user_id"]);
session_destroy();

require_once "server_files/views/header.php";
?>

<div class="alert alert-success">
    Déconnexion réussie !
</div>

<?php
require_once "server_files/views/footer.php";