<?php
$dsn = "mysql:host=localhost;dbname=mg";
$username = "root";
$password = "";
$options = array(
PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
);

try{
$conn = new PDO($dsn,$username,$password,$options);
} catch (PDOException $e){
echo "Error!".$e->getMessage();
}

?>

<?php
session_start();
if(isset($_SESSION['user'])){
header("location: general message.php");
}
require "connection.php";

if(isset($_POST['login'])){
$user = $_POST['username'];
$pass = md5($_POST['password']);
$messeg = "";

if(empty($user) || empty($pass)) {
    $messeg = "Username/Password con't be empty";
} else {
    $sql = "SELECT username, password FROM users WHERE username=? AND
  password=? ";
    $query = $conn->prepare($sql);
    $query->execute(array($user,$pass));

    if($query->rowCount() >= 1) {
        $_SESSION['user'] = $user;
        $_SESSION['time_start_login'] = time();
        header("location: general message.php");
    } else {
        $messeg = "Username/Password is wrong";
    }
}
}

?>

//The lives of session is one hour 60*60=3600

<?php
session_start();

if(isset($_SESSION['user'])){
if((time() - $_SESSION['time_start_login']) > 3600){
    header("location: logout.php");
} else {
    $_SESSION['time_start_login'] = time();
}
} else {
header("location: logout.php");
}
 ?>

<?php
session_start();
session_destroy();
header("location: index.php");
?>

// 60*60=3600 one hour

<meta http-equiv="Refresh" content="3600" >

<?php
require ('site life.php');
?>

try{
$conn = new PDO($dsn,$username,$password,$options);
} catch (PDOException $e){
echo "Error!".$e->getMessage();
}

if($query->rowCount() >= 1) {