Are there any specific security considerations to keep in mind when implementing user online status functionality in PHP?

When implementing user online status functionality in PHP, it is important to consider security measures to prevent unauthorized access to user status information. One way to enhance security is by implementing proper authentication and authorization checks to ensure that only authenticated users can access the online status of other users. Additionally, it is crucial to sanitize user input to prevent SQL injection attacks and validate user permissions before displaying any sensitive information.

// Check if user is authenticated before displaying online status
if(isset($_SESSION['user_id'])){
    // Retrieve user's online status from database
    $user_id = $_GET['user_id'];
    
    // Perform authentication and authorization checks
    if($_SESSION['user_id'] == $user_id){
        // Display user's online status
        $online_status = getUserOnlineStatus($user_id);
        echo "User is $online_status";
    } else {
        echo "Unauthorized access";
    }
} else {
    echo "Please log in to view online status";
}