How can PHP developers continue a session with a specific user id and where should this id be input?

To continue a session with a specific user id in PHP, you can store the user id in a session variable when the user logs in. This id should be input when starting or resuming the session to ensure that the session is maintained for that specific user. 

<?php
session_start();

// Set the user id in a session variable when the user logs in
$_SESSION['user_id'] = $user_id;

// Input the user id when starting or resuming the session
if(isset($_SESSION['user_id'])) {
    // Continue session for the specific user
} else {
    // Redirect or handle the case where user id is not set
}
?>

Keywords

PHP session management user id session_start() input validation

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