too long

Question

i want to start a new session using a cookie, once the previous session has been destroyed.

if a cookie is set, but not a session, can i automatically, create a new session using only the cookie?

currently, i am implementing a remember me button. and part of my loggin code is

if($rememberme=="on"){
            $user_id=mysql_result($query_run,0,'id');
            setcookie("user_id",$user_id,time()+7200);
            $_SESSION['user_id']=$_COOKIE['user_id'];
            header('Location:front_page.php');
        }else if($rememberme==""){
            echo'ok';
            $user_id=mysql_result($query_run,0,'id');
            echo $user_id;
            $_SESSION['user_id']=$user_id;
            header('Location:front_page.php');

i need to do this because if a cookie is set, but not a session, it is causing various errors on my site. because i am using the $_SESSION['userid'] variable in various places. and if the session is not set, many of my functions are not working

edit: i tried the following and it did not work.

i want to start a new session using a cookie, once the previous session has been destroyed. any other suggestions?

set_session_from_cookie();

function set_session_from_cookie(){
if(isset($_COOKIE['user_id'])){
    $_SESSION['user_id']=$_COOKIE['user_id'];
}
}

Answer 1

I suggest you to use a different way for the "remember me" functionality.

You can check if the "remember me" checkbox is checked then generate a UNIQUE and secret key and put the key inside a cookie and in some user row in database.

Now, somewhere at top of pages, check for the cookie then if needed, set session.

Example

if(isset($_COOKIE["c_key"]) && !isset($_SESSION["userId"])) 
{ 
     /*
      * Here check for users matching $_COOKIE["c_key"] in database and get the userId
      */
     $_SESSION["userId"] = $user_data["userId"]; 
}

And keep using session everywhere.