PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

522 Chapter 23 Using Session Control in PHP
{
// if they are in the database register the user id
$_SESSION[‘valid_user’] = $userid;
}
$db_conn->close();
}
Because you now know who the user is, you don’t need to show her the login form
again. Instead, you can tell her you know who she is and give her the option to log out:
if (isset($_SESSION[‘valid_user’]))
{
echo ‘You are logged in as: ‘.$_SESSION[‘valid_user’].’ ’;
echo ‘Log out’;
}
If you tried to log her in and failed for some reason, you’ll have a userid but not a
$_SESSION[‘valid_user’] variable, so you can give her an error message:
if (isset($userid))
{
// if they’ve tried and failed to log in
echo ‘Could not log you in.’;
}
That’s it for the main script. Now, let’s look at the Members page.The code for this
script is shown in Listing 23.5.
Listing 23.5 members_only.php—The Code for the Members’ Section of the Website
Checks for Valid Users