Redirect to log in page if session does not exist in PHP -

so have page can accessed if user logged in. if not, redirected home page (if user visits page directly). want do, redirect user login page, , if login successful, redirected page.

basically , in simplified way, concepts are:

first, start session inside pages using sessions:

session_start(); 

then, check in pages:

if(!isset($_session['is-user-logged'])){     header("location: login.php");     exit; } 

in login in page:

if($_post){     // .. process form here , check if user submitted valid credentials.      $_session['is-user-logged'] = 1;     header("location: home.php");     exit; } 

on logout page:

session_destroy(); header("location: login.php"); exit;