Question

I have a cronjob system with PHP. I have a file named cron.php and wanna to check if it is not loaded, load it. it is very important to me that this file run only one time and I need the way how define it is already running. I can’t use any system functions like exec,system,… do you have any solutions?

NOTE: I run my script trough CURL and include_one and require_once don’t work for this case.

Answer 1

You could use flock() to lock the php file itself, like this:

<?php

class Lock{
    private $fp;
    function __construct(){
        $this->fp=fopen(__FILE__,'r');
        if (!flock($this->fp,LOCK_EX|LOCK_NB)) {
            die('already running !'.PHP_EOL);
        }       
    }
    function __destruct(){
        flock($this->fp,LOCK_UN);
        fclose($this->fp);  
    }
}

$lock=new Lock();


// simulate some processing
sleep(60);


echo "END";
?>