iflogin.php

<?php
session_start();
require('config.php');
// check if logged in
function iflogin(){
    // connect to database
    $con = new PDO('mysql:host='.DB_HOST.';dbname='.DB_DB.';charset=utf8_general_ci', DB_USERNAME, DB_PASSWORD, array(PDO::ATTR_EMULATE_PREPARES => false, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
    $con->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);

    // delete old users
    $query = $con->prepare('DELETE * FROM `active_users` WHERE `expires`<=`:time`');
    $query->bindValue(':time', time());
    $query->execute();

    // find current user in active users
    $sql = $con->prepare('SELECT * FROM `active_users` WHERE `session_id` = `:sessid`');
    $sql->bindValue(':sessid', session_id());
    $res = $sql->fetch();

    if($res->rowCount()){
        // is logged in
        return true;
    }else{
        //is not logged it (or timed out)
        header('location: ' . HOST);
        return false;
    }
}
// extend user log in session, so he can use it longer (the default timeout from current time)
function extendSession(){
    // connect to database
    $con = new PDO('mysql:host='.DB_HOST.';dbname='.DB_DB.';charset=utf8_general_ci', DB_USERNAME, DB_PASSWORD, array(PDO::ATTR_EMULATE_PREPARES => false, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
    $con->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);

    // calculate new timeout
    $newexp = time() + (60 * SESSION_LENGTH);

    // insert new timeout: prepare
    $myquery = $con->prepare('UPDATE `active_users` SET `expires`=`:expires` WHERE `session_id`=`:id`');
    // bind values
    $myquery->bindValue(':expires',$newexp);
    $myquery->bindValue(':id', session_id());
    // execute
    $myquery->execute();
}
?>