Question

I am using the following code:

$fp = fopen("lock.txt", "w");
if (flock($fp, LOCK_EX|LOCK_NB)) { // do an exclusive lock
    //Do something here.
}else{
   echo "Could not lock file!";
}

This code runs fine when I run my script from my browser (it locks and I can only run it once) but when running it via cron job, the lock.txt file isn’t even created. I am a little stumped as I presume the Cron runs as the same user that runs the browser version so it obviously has permissions.

Anyone else had something like this?

EDIT: Ok the file is created now I have done specific paths to the directory. However, the file is overwritten everytime the cron starts an isn’t actually locking the file.

Answer 1

This is the correct way to do that.

<?php
$tempDir = sys_get_temp_dir() . "/";
$fp = fopen("$tempDirlock.txt", "r+");

if (flock($fp, LOCK_EX | LOCK_NB)) { // do an exclusive lock
    // do the work

    flock($fp, LOCK_UN); // release the lock
} else {
    echo "Couldn't get the lock!";
}

fclose($fp);
?>