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  Classes of Barbushin Sergey  >  Script Alone  >  example.php  >  Download  
File: example.php
Role: Example script
Content type: text/plain
Description: Example
Class: Script Alone
Manage the execution of PHP daemon scripts
Author: By
Last change:
Date: 5 years ago
Size: 3,470 bytes
 

Contents

Class file image Download
<?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');