Tracking changes in text file with PHP

Question

I have a PHP script that has to reload a page on the client (server push) when something specific happens on the server. So I have to listen for changes. My idea is to have a text file that contains the number of page loads for the current page. So I would like to monitor the file and as soon as it is modified, to use server push in order to update the content on the client. The question is how to track the file for changes in PHP?

Answer 1

You could do something like:

<?php
while(true){
    $file = stat('/file');
    if($file['mtime'] == time()){
        //... Do Something Here ..//
    }
    sleep(1);
}

This will continuously look for a change in the modified time of a file every second. If you don't constrain it you could kill your disk IO and may need to adjust your ulimit.