» PHPCron - Cronjobs ohne Crontab

<?php
// (c) 2015 http://Gutt.IT/
/* PHPCron V1.1 */
define('WEBMASTER_EMAIL', 'john.doe@example.org');
function isSecure() {
	return ((isset($_SERVER['HTTPS']) && !empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') || $_SERVER['SERVER_PORT'] == 443) ? 's' : '';
}
function _get($var, $else=null, $force=false) {
	if (!$force) {
		return isset($_GET[$var]) ? $_GET[$var] : $else;
	}
	else {
		$force = array_flip($force);
		return isset($_GET[$var]) && isset($force[$_GET[$var]]) ? $_GET[$var] : $else;
	}
}
function display_tracking_image() {
	header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
	// image data
	$im = imagecreate(1, 1);
	$blk = imagecolorallocate($im, 0, 0, 0);
	imagecolortransparent($im, $blk);
	// image output
	header("Content-type: image/gif");
	imagegif($im);
	// free memory
	imagedestroy($im);
}
function cron_request($sec) {
	$sec = intval($sec);
	$cron_filename = 'cache/' . $sec . '_crnsec_lock';
	if (file_exists($cron_filename) || !mkdir($cron_filename)) {
		return;
	}
	// add one minute if necessary
	$date = new DateTime();
	$cron_date = new DateTime();
	$cron_date->setTime($cron_date->format('H'), $cron_date->format('i'), $sec);
	$diff = $date->diff($cron_date);
	if ($diff->invert && $diff->s > 0) {
		$cron_date->setTime($cron_date->format('H'), $cron_date->format('i') + 1, $sec);
	}
	$diff = $date->diff($cron_date);
	// we use sleep() as time_sleep_until() starts one second to early (https://bugs.php.net/bug.php?id=69044)
	sleep($diff->s);
	// str > regex
	$request_uri = $_SERVER['REQUEST_URI'];
	if (strpos($request_uri, 'cron_second=') === false) {
		$request_uri .= (strpos($request_uri, '?') === false ? '?' : '&') . 'cron_second=' . $sec;
	}
	else {
		$request_uri = str_replace(array('&cron_second=', '?cron_second='), 'cron_second=', $request_uri);
		$request_uri = str_replace(array('cron_second=0', 'cron_second=15', 'cron_second=30', 'cron_second=45'), '', $request_uri);
		$request_uri .= (strpos($request_uri, '?') === false ? '?' : '&') . 'cron_second=' . $sec;
	}
	// note: filter_input returns the unchanged SERVER var (http://php.net/manual/de/function.filter-input.php#99124)
	// note: filter_var is unsecure (http://www.d-mueller.de/blog/why-url-validation-with-filter_var-might-not-be-a-good-idea/)
	$url = 'http' . isSecure() . '://' . filter_input(INPUT_SERVER, 'HTTP_HOST', FILTER_SANITIZE_URL) . htmlspecialchars($request_uri, ENT_QUOTES, 'UTF-8');
	$context = stream_context_create(array(
		'http' => array(
			'timeout' => 1.0
		)
	));
	// note: return "failed to open stream: HTTP request failed!" because timeout < time_sleep_until
	if ($fp = @fopen($url, 'r', false, $context)) {
		fclose($fp);
	}
	rmdir($cron_filename);
}
function mycron($title) {
	mail(WEBMASTER_EMAIL, "this cron runs $title " . date('c'), htmlspecialchars($_SERVER['REQUEST_URI'], ENT_QUOTES, 'UTF-8'));
}
if (!ini_get('allow_url_fopen')) {
	mail(WEBMASTER_EMAIL, 'allow_url_fopen', 'fopen not possible on this host!');
	exit;
}
if (!file_exists('cache/')) {
	if (!mkdir('cache')) {
		mail(WEBMASTER_EMAIL, 'cache', 'cache folder does not exist and it was not possible to create it!');
	}
	exit;
}
$allowed_crons = array(0, 15, 30, 45);
$cron_second = intval(_get('cron_second', 0, $allowed_crons));
$cron_filename = 'cache/' . $cron_second . '_crnsec_lock';
if (isset($_GET['cron_second'])) {
	if ($cron_second === 0 && !(date('i') % 15)) {
		mycron('every 15 minutes');
	}
	if ($cron_second === 0 && !(date('i') % 60)) {
		mycron('every hour');
	}
}
// cron monitoring
foreach ($allowed_crons as $cron_second) {
	$cron_filename = 'cache/' . $cron_second . '_crnsec_lock';
	// start missing cron requests
	if (!file_exists($cron_filename)) {
		cron_request($cron_second);
	}
	// restart interrupted cron requests
	else if (filemtime($cron_filename) + 90 < time()) {
		rmdir($cron_filename);
		cron_request($cron_second);
	}
}
if (!headers_sent()) {
	display_tracking_image();
}
?>

• das Script muss manuell gestartet werden (außer man bindet es irgendwo ein)
• es werden in der Regel mehr http Requests auf dem Server verursacht als Cronjobs notwendig sind

<img src="cronjob.php" width="1" height="1" alt="" />

Mach mit!