In what scenarios would using HTML5 Server-Sent Events be a suitable solution for PHP applications?

HTML5 Server-Sent Events can be a suitable solution for PHP applications when real-time updates or notifications need to be sent from the server to the client without the client needing to constantly poll the server for updates. This can be useful for applications such as chat rooms, live updates, or notifications.

<?php
header('Content-Type: text/event-stream');
header('Cache-Control: no-cache');

// Simulate real-time updates every 5 seconds
while (true) {
    $data = // Fetch data from database or other source

    echo "data: " . json_encode($data) . "\n\n";
    flush();
    sleep(5);
}
?>