<?php
/**
*
* @desc This is example of using class ScriptAlone.
*
* Example task: you have a live queue of emails(for example in DB) that must
* be sent as soon as possible.
*
* 1. You need to have some PHP-script that will check if there are any emails
* in queue, and if yes so send them.
* 2. This PHP-script must be runned all time, and check queue every second.
* 3. Only one instance of this PHP-script can be runned, to be shure that one
* email was not sent twice.
* 4. PHP-script can be interrupted in any moment by some error, so in this
* case it must be restarted as soon as possible.
* 5. PHP-script can have a bug on some iteration, mean: it will be lunched
* but not sending emails, so in this case it must be restarted as soon
* as possible.
* 6. PHP-script should be restarted every 5-10 hours to prevent memory leaks
* and do it in safe way (when all current tasks are complete)
* 7. Ability to stop script in any moment.
*
* What you do:
* 1. Use ScriptAlone in way like in this PHP-script.
* 2. Configure CRON(http://wikipedia.org/wiki/Cron) that will lunch this
* PHP-script every 5 minutes.
*
* What you have:
* 1. Script will be runned all time, and checked emails every second.
* 2. There will be only one instance of runned script.
* 3. Script will be restarted if there will be any errors or iteration time
* limit expire.
* 3. Script will be restarted in safe way every 5 hours.
* 4. You can any time check if script is runned by checking existing file
* with $stateFilepath path (./examples.php.works)
* 5. You can any time stop runned script by creating file with path
* $stateFilepath.'.stop' (./examples.php.works.stop).
* 6. All script restarts takes maximum 5 minutes (because of CRON try to run
* next script instance every 5 minute).
*
* @see http://code.google.com/p/dabase
* @author Barbushin Sergey http://www.linkedin.com/in/barbushin
*
*/
// example function that sends emails from queue
function sendEmailsFromQueue($limit) {
// ... send some emails from queue
return mt_rand(0, 3); // return count of sent emails
}
function _debug($message) {
echo $message.'<br />';
flush();
}
define('PAUSE_SECONDS_ON_EMPTY_QUEUE', 1);
define('EMAILS_GET_FROM_QUEUE', 5);
define('MAX_SECONDS_TO_SEND_ONE_EMAIL', 3);
$withoutNotifyLifetime = EMAILS_GET_FROM_QUEUE * MAX_SECONDS_TO_SEND_ONE_EMAIL + PAUSE_SECONDS_ON_EMPTY_QUEUE;
$stateFilepath = __FILE__.'.works';
$scriptLifetime = 60*60*5;
// if FALSE so you should check $scriptAlone->isReadyToStop() every time
// if TRUE so checking of $scriptAlone->isReadyToStop() will be doing automaticly in every calling of $scriptAlone->notifyItWorks()
// and if $scriptAlone->isReadyToStop() == true, so $scriptAlone->notifyItWorks() will throw exception of class ScriptAlone_Stopped
$stopOnReadyToStop = false;
require_once('ScriptAlone.php');
$scriptAlone = new ScriptAlone($stateFilepath, $withoutNotifyLifetime, $scriptLifetime, $stopOnReadyToStop);
_debug('script is runned, you can see it by created file'.$stateFilepath);
while (!$scriptAlone->isReadyToStop()) {
_debug('sendEmailsFromQueue');
if (!sendEmailsFromQueue(EMAILS_GET_FROM_QUEUE)) {
_debug('sleep');
sleep(PAUSE_SECONDS_ON_EMPTY_QUEUE);
}
_debug('notifyItWorks');
$scriptAlone->notifyItWorks();
}
_debug('done');
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